A new study demonstrates the physics that elephants use to feed themselves the massive quantities of leaves, fruit and roots needed to sustain their multi-ton bodies.
A human can pick up multiple objects at once by squeezing them together with both hands and arms. An African elephant also picks up many items at once but with only one appendage—its soft, heavy trunk. How the elephant solves this challenge could provide inspiration for future robotics.
A wild African elephant eats rapidly, consuming 190 grams of food a minute, to provide adequate fuel for its vast bulk. “Elephants are in a rush when they are eating,” said David L. Hu, associate professor in the School of Mechanical Engineering and the School of Biology at the Georgia Institute of Technology. The elephant diet consists of large volumes of plant materials such as leaves, fruit and roots. To eat these, elephants sweep loose items into a pile and crush them into a manageable solid that can be picked up by the trunk.
“They don’t just use the trunk’s strong muscles to squeeze the plants together,” said Hu. “The elephants also use the weight of the trunk, and they do that by forming a joint in the trunk. The trunk below the joint becomes a stiff pillar that applies weight to the pile of plant materials.”
About 30 percent of the applied force is derived from the pillar’s weight alone, and about 70 percent from exerting muscular effort, according to a new study published in the Journal of the Royal Society Interface by Hu and colleagues at Georgia Tech, the Rochester Institute of Technology and Zoo Atlanta.
The African elephant can raise or lower the trunk joint’s height by up to 11 centimeters to increase or reduce the applied force. “When elephants need more force, the joint is higher up on the trunk,” Hu said. Elephant trunks weigh about 150 kilograms and have 40,000 muscles. “The huge number of muscles in the trunk allows the elephant great freedom for where it puts this joint.”
Hu and his colleagues studied a 34-year-old female African elephant (Loxodonta africana) over several weeks in the summer of 2017. All experiments were supervised by the staff at Zoo Atlanta. Food was arranged by hand into a pile in the center of a force plate to measure how much force the animal generated.
The elephant’s trunk is similar to other boneless organs in nature such as the octopus’s arm and the human tongue. But unlike an octopus’s arm, an elephant’s trunk is heavy enough to provide significant force on an object without muscular pressure. This is the first study to show that an animal can use the weight of its own appendage to help apply force and the first with a live elephant to understand forces that it can apply to materials.
Using mathematical models, the researchers found that the greater the number of objects to be squeezed and picked up, the greater the force that must be applied.
“Picking up two objects requires very little force to press them together, while picking up 40,000 objects requires a lot of force,” Hu said. This principle was tested experimentally with the live elephant by presenting multiple food items varying in number from four to 40,000 in number. The experiments showed that the elephant could vary forces applied with its trunk by a factor of four depending on the number of food items to be picked up.
This research could have applications in robotics, where heavier machines would appear to have few advantages over smaller ones. But, in the future, heavy robotic manipulators could be designed with several adjustable joints that use the device’s own weight to provide adjustable pressure and save energy. There are currently no commercial robots designed to apply their own weight to objects, Hu noted.
“You could have future robots with several joints, which could apply various weight pressures below joints to help compress objects together for lifting them efficiently,” said Hu. “This would allow you to use the weight of the joints themselves to provide force instead of relying on batteries and extra motors to apply these forces, and that would mean using less energy. For instance, you could have a heavy robot with four joints, and by bending the top joint, the weight below it could apply a load. If you wanted to provide less weight pressure, you could instead bend the second-from-the-top joint. This study shows that there are some advantages for robots in being big and heavy.”
African elephants like the ones in this study have two muscular extensions at the tip of their trunk resembling a pair of fingers that also could be studied as models for future robotics. It’s not well known that elephants have such projections, and this understanding could inform work that is already underway. “The elephant’s technique with these extensions might be used to develop soft robotic grippers that can pick up delicate items such as fruit without damaging them,” Hu noted.
This work was supported by the U.S. Army Research Laboratory and the U.S. Army Research Office Mechanical Sciences Division, Complex Dynamics and Systems Program, under contract W911NF-12-R-0011.
CITATION: Jianing Wu, et al., “Elephant trunks form joints to squeeze together small objects,” (Journal of the Royal Society Interface 15, 2018) http://dx.doi.org/10.1098/rsif.2018.0377
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Episode 7 of ScienceMatters' Season 1 stars Jennifer Leavey. Listen to the podcast here and read the transcript here.
Jennifer Leavey is a principal academic professional in the School of Biological Science. She also serves College of Sciences as the coordinator of the Integrated Science Curriculum and director of Georgia Tech Urban Honeybee Project.
The Georgia Tech Urban Honey Bee Project is an interdisciplinary educational initiative to recruit and retain students in STEM careers through the study of how urban habitats affect honey bee health and how technology can be used to study bees.
Leavey is also the faculty director of the Science and Math Research Training (SMaRT) and Scientific Health and Related Professions (SHaRP) Living Learning Communities of the College of Sciences.These communities aim to create lasting connections among College of Sciences majors who are interested in research (SMaRT) or intend to pursue additional education and training health-rleated fields.
In Episode 7 of ScienceMatters, Leavey shares her long-lasting passion for both science and rock music. By day, she’s an academic professional; but when she straps on a guitar , she mutates to Leucine Zipper, leader of the rock band Zinc Fingers.
For a change of pace, ScienceMatters samples the band’s science-inspired songs. Leavey shares how the band uses music and other media to make science concepts fun and accessible.
Take a listen at sciencematters.gatech.edu.
Enter to win a prize by answering the question for Episode 7:
In episode 7, what is the name of the song that Jennifer Leavey says sounds like a love song but is actually about bacteria living together in biofilms?
Submit your entry by 11 AM on Monday, Oct. 8, at sciencematters.gatech.edu. Answer and winner will be announced shortly after the quiz closes.
Jennifer Leavey is the integrated science curriculum coordinator for the College of Sciences. She also directs the Georgia Tech Urban Honey Bee Project, an interdisciplinary initiative designed to recruit and retain STEM students by studying how urban habitats affect honey bee health and how technology can be used to study bees.
“Most of the programs I work on relate to encouraging undergraduates to become more engaged in studying science,” Leavey said. “The Georgia Tech Urban Honey Bee Project sprouted out of the idea that if something is authentic, it doesn’t matter what discipline students are in or what class they’re taking, they’ll become interested in it.”
Learn more about Jennifer Leavey's activities, including leading a science rock band, in the full story by Victor Rogers.
In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biology in the School of Biological Sciences Deanna Beatty will defend her dissertation Effects of Macroalgal Versus Coral Reef Dominance on Coral Survival, Chemical Defense, and Microbiomes.
Thesis Advisor:
Dr. Mark Hay
School of Biological Sciences
Georgia Institute of Technology
Committee members:
Dr. Frank Stewart
School of Biological Sciences
Georgia Institute of Technology
Dr. Julia Kubanek
School of Biological Sciences
Georgia Institute of Technology
Dr. Danielle Dixson
School of Marine Science and Policy
University of Delaware
Dr. Kim Ritchie
School of Science and Mathematics
University of South Carolina Beaufort
SUMMARY
Coral reefs are among the earth’s most biodiverse and productive ecosystems, but are undergoing precipitous decline due to coral bleaching and disease following thermal stress events, which are increasing in frequency and spatial scale. These effects are exacerbated by local stressors such as overfishing and pollution, collectively causing an increasing number of reefs to shift from coral to macroalgal dominance. These stressors can harm or kill corals through diverse mechanisms, including alterations in how corals interact with microorganisms. By employing a variety of field sampling and field experimental approaches, I investigated consequences of local protection from fishing and coral versus macroalgal dominance of the benthos on coral survival, chemical defense, and microbiomes within paired algal dominated fished areas and coral dominated marine protected areas (MPAs) in Fiji. I demonstrate that i) coral larvae from a macroalgal dominated area exhibited higher pre-settlement mortality and reduced settlement compared to those from a coral dominated area, ii) juveniles planted into a coral dominated MPA survived better than those planted into a macroalgal dominated fished area and differential survival depended on whether macroalgae were immediately adjacent to juvenile coral, iii) corals possess chemical defenses toward the thermally-regulated coral bleaching pathogen Vibrio coralliilyticus, but this defense is compromised by elevated temperature, iv) for a bleaching susceptible but ecologically important acroporid coral, anti-pathogen chemical defense is compromised when coral resides within macroalgal dominated reefs and this effect can be influenced by both the current and historic state of the reef. Effects on coral survival and chemical defense for individuals residing within coral versus macroalgal dominated areas largely coincided with nuanced differences in coral microbiomes (e.g., in microbiome variability and specific indicator bacterial taxa) but not with major shifts in microbiome composition. These findings have implications for reef conservation and for understanding how coral-microbe interactions will respond to the pressures of global change.
Event Details
Nolan English
School of Biological Sciences
Advisor: Dr. Matthew Torres (School of Biological Sciences)
Committee Members:
Dr. Melissa Kemp, School of Biomedical Engineering; Georgia Institute of Technology
Dr. Raquel Lieberman, School of Chemistry and Biochemistry; Georgia Institute of Technology
Dr. Peng Qiu, School of Biomedical Engineering; Georgia Institute of Technology
Dr. Christopher Rozell, School of Electrical and Computer Engineering; Georgia Institute of Technology
Abstract:
Post-translational modifications (PTMs) provide an extensible framework for regulation of protein behavior beyond the diversity represented within the genome alone. While the rate of identification of PTMs has rapidly increased in recent years, our knowledge of PTM functionality remains limited. Fewer than 4% of all eukaryotic PTMs are reported to have biological despite their ubiquity across the proteome. This percentage continues to decrease as the pace of identification of PTMs surpasses the rate that PTMs are experimentally researched. To bridge the gap between identification and interpretation we have developed SAPH-ire, Structural Analysis of PTM Hotspots, a machine learning based tool for prioritizing PTMs for experimental study by functional potential. In this thesis, I aim to expand SAPH-ire’s functionality to predict potential function and improve its performance in ranking PTMs by functional potential. Here I will first discuss some challenges facing computational PTM research from an informatics perspective. I will then discuss the creation of new resources to address these challenges in four objectives. First, the creation of a new data resource that captures experimental data from mass spectrometry experiments designed to focus on PTMs. Second, the renovation of the SAPH-ire machine learning model to improve model performance and predictive recall. Third, the generation of a new model capable of discerning function from functional potential and structural features. Fourth, the development of a visual interface for SAPH-ire and the data resource that enhance one’s ability to understand the model’s results and drives further study.
Post-translational modifications (PTMs) provide an extensible framework for regulation of protein behavior beyond the diversity represented within the genome alone. While the rate of identification of PTMs has rapidly increased in recent years, our knowledge of PTM functionality remains limited. Fewer than 4% of all eukaryotic PTMs are reported to have biological despite their ubiquity across the proteome. This percentage continues to decrease as the pace of identification of PTMs surpasses the rate that PTMs are experimentally researched. To bridge the gap between identification and interpretation we have developed SAPH-ire, Structural Analysis of PTM Hotspots, a machine learning based tool for prioritizing PTMs for experimental study by functional potential. In this thesis, I aim to expand SAPH-ire’s functionality to predict potential function and improve its performance in ranking PTMs by functional potential. Here I will first discuss some challenges facing computational PTM research from an informatics perspective. I will then discuss the creation of new resources to address these challenges in four objectives. First, the creation of a new data resource that captures experimental data from mass spectrometry experiments designed to focus on PTMs. Second, the renovation of the SAPH-ire machine learning model to improve model performance and predictive recall. Third, the generation of a new model capable of discerning function from functional potential and structural features. Fourth, the development of a visual interface for SAPH-ire and the data resource that enhance one’s ability to understand the model’s results and drives further study.
Post-translational modifications (PTMs) provide an extensible framework for regulation of protein behavior beyond the diversity represented within the genome alone. While the rate of identification of PTMs has rapidly increased in recent years, our knowledge of PTM functionality remains limited. Fewer than 4% of all eukaryotic PTMs are reported to have biological despite their ubiquity across the proteome. This percentage continues to decrease as the pace of identification of PTMs surpasses the rate that PTMs are experimentally researched. To bridge the gap between identification and interpretation we have developed SAPH-ire, Structural Analysis of PTM Hotspots, a machine learning based tool for prioritizing PTMs for experimental study by functional potential. In this thesis, I aim to expand SAPH-ire’s functionality to predict potential function and improve its performance in ranking PTMs by functional potential. Here I will first discuss some challenges facing computational PTM research from an informatics perspective. I will then discuss the creation of new resources to address these challenges in four objectives. First, the creation of a new data resource that captures experimental data from mass spectrometry experiments designed to focus on PTMs. Second, the renovation of the SAPH-ire machine learning model to improve model performance and predictive recall. Third, the generation of a new model capable of discerning function from functional potential and structural features. Fourth, the development of a visual interface for SAPH-ire and the data resource that enhance one’s ability to understand the model’s results and drives further study.
Event Details
A Frontiers in Science Lecture by Mindy-Millard Stafford, School of Biological Sciences
Recent work from the lab of Mindy Millard-Stafford brings attention to the cognitive effects of dehydration. The findings have garnered immense media attention, from Newsweek and National Public to Men’s Health Magazine. Millard-Stafford discusses her Georgia Tech research leading up to this widely noticed work.
She will discuss: Why is water essential? How much do we need? Is water the most hydrating beverage? Can you drink too much water? And based on one media headline -- Does dehydration make you dumber?
She will reflect on the unexpected media blitz: how it happened and what lessons we might take away from this experience.
Light refreshments will be served after the lecture.
About The Speaker
A member of the Georgia Tech faculty for more than three decades, Mindy Millard-Stafford is a professor in the School of Biological Sciences, where she directs the Exercise Physiology Laboratory.
She is past president of the American College of Sports Medicine and member of the National Academy of Kinesiology.
The goals of her research are to seek nutritional and exercise interventions that can improve human health, well-being, and performance. Her lab is particularly focused on the importance of hydration to delay fatigue and maintain safety during exercise, especially in conditions of heat stress.
About The Frontiers in Science Lecture Series
Lectures in this series are intended to inform, engage, and inspire students, faculty, staff, and the public on developments, breakthroughs, and topics of general interest in the sciences and mathematics. Lecturers tailor their talks for nonexpert audiences.
Event Details
College of Sciences faculty, staff, and students are invited to join Provost Rafael L. Bras and Search Committee Chair Pinar Keskinocak, for a town hall to learn about the dean search process and timeline, and to provide feedback on the characteristics of the ideal candidate.
The international search for the new dean for the College of Sciences will be chaired by Pinar Keskinocak, William W. George Chair, H. Milton Stewart School of Industrial and Systems Engineering; College of Engineering ADVANCE Professor; and Director, Center for Health and Humanitarian Systems. The individual selected by this search committee will also hold the Betsy Middleton and John Clark Sutherland Chair.
Event Details
Episode 2 of ScienceMatters' Season 1 stars Jenny McGuire. The assistant professor in the School of Earth and Atmospheric Sciences and the School of Biological Sciences has a tough commute to her summer research site: An 80-foot drop into Wyoming’s deep, dark Natural Trap Cave. There she collects fossils that she hopes will yield clues about the impact of climate change on animal and human populations.
Follow her journey at sciencematters.gatech.edu.
Enter to win a prize by answering the episode's question:
What small four-legged animals mentioned in Episode 2 help Jenny McGuire collect bones from Natural Trap Cave?
Submit your entry by noon on Friday, Aug. 31, at sciencematters.gatech.edu. Answer and winner will be announced on Monday, Sept. 3.
Congratulations to Vineeth Aljapur, winner of Episode 1 quiz. Aljapur is a first-year student in the Georgia Tech Bioinformatics Graduate Program.
Episode 3 of ScienceMatters' Season 1 stars M.G. Finn. Listen to the podcast and read the transcript here!
Leishmaniasis is a scary parasitic disease; it can rot flesh. Formerly contained in countries near the equator, it has arrived in North America. School of Chemistry and Biochemistry Professor and Chair M.G. Finn explains why it’s so tough to fight this disease. His collaboration with Brazilian researcher Alexandre Marques has raised hopes for a possible vaccine.
Follow the the researchers' journey at sciencematters.gatech.edu.
Enter to win a prize by answering the episode's question:
What sugar molecule mentioned in Episode 3 is the main reason surgeons can’t transplant organs from animals into humans?
Submit your entry by noon on Friday, Sept. 7, at sciencematters.gatech.edu. Answer and winner will be announced on Monday, Sept. 10.
Results of Episode 2 Quiz
Q: What small four-legged animals mentioned in Episode 2 help Jenny McGuire collect bones from Natural Trap Cave?
A: Wood rats, pack rats, or rats
The winner is Pedro Marquez Zacarias. He was listening to ScienceMatters while doing routine data analysis for his research.
A third-year Ph.D. student in the Georgia Tech Quantitative Biosciences Graduate Program, Marquez Zacarias aims to add to the understanding of how biological complexity evolved, particularly multicellularity.
Marquez Zacarias comes from a small town in rural México, an indigenous community called Urapicho, in the state of Michoacán.
They may look a little like space capsules, but nuclear magnetic resonance spectrometers stay planted on the floor and use potent magnetism to explore opaque constellations of molecules.
Three Atlanta area universities jointly launched a nuclear magnetic resonance collaboration called the Atlanta NMR Consortium to optimize the use of this technology that provides insights into relevant chemical samples containing so many compounds that they can otherwise easily elude adequate characterization. The consortium has been operating since July 2018.
Crab pee
Take, for example, crab urine. It’s packed with hundreds to thousands of varying metabolites, and researchers at the Georgia Institute of Technology wanted to nail down one or two of them that triggered a widespread crab behavior. Without access to NMR they may not have found them at all even after an extensive search.
The spectrometer pulled the right two needles out of the haystack, so the researchers could test them on the crabs and confirm that they were initiating the behavior.
Emory University, Georgia State University and Georgia Tech already have NMR technology, but the Atlanta NMR Consortium will enable them to fully exploit it while cost-effectively staying on top of upgrades.
“NMR continues to grow and develop because of technological advances,” said David Lynn, a chemistry professor at Emory University.
That means buying new machines every so often, and one new NMR spectrometer can run into the millions; annual maintenance for one machine can cost tens of thousands of dollars. Thus, reducing costs and maximizing usage makes good sense.
Medicine, geochemistry
The human body, sea-side estuaries, and rock strata present huge collections of compounds. NMR takes inventory of complex samples from such sources via the nuclei of atoms in the molecules.
A nucleus has a spin, which makes it magnetic, and NMR spectrometry’s own powerful magnetism detects spins and pinpoints nuclei to feel out whole molecules. These can be large or small, from mineral compounds with three or four component atoms to protein polymers with tens of thousands of parts.
Researchers in medicine, biochemistry, ecology, geology, food science – the possible list is exhaustive -- turn to NMR to untangle their particular molecular jungles. The consortium wants to leverage that diversity.
“As we go in different directions, we will benefit from a cohesive community of people who know how to use NMR for a wide range of problems,” said Anant Paravastu, an associate professor in Georgia Tech’s School of Chemical and Biomolecular Engineering.
“The most important goal for us is the sharing of our expertise,” said Markus Germann, a professor of chemistry at Georgia State.
Consortium members will benefit the most from the pooled NMR resources, but non-partners can also book access. Read more about the Atlanta NMR Consortium here on Georgia Tech’s College of Sciences website
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