from the world's big
Non-avian dinosaurs were thought terrestrially bound, but newly unearthed fossils suggest they conquered prehistoric waters, too.
Unearthing a mystery in the desert<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzE4MDU1OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNzI1NTExM30.1L90N5rrjAiYqBzRa72_b3hmP8Bq20MdZ3KtdfSgUTg/img.jpg?width=1245&coordinates=0%2C24%2C0%2C262&height=700" id="765d6" class="rm-shortcode" data-rm-shortcode-id="45a87235d3fe79b339ade44f58f9818c" data-rm-shortcode-name="rebelmouse-image" />
Stromer's holotype of his original Spinosaurus specimen.
A digital resurrection<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzE4MDU1OS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTU5NTM2MTExOX0.YuUzxvnm_mHQYTvH2e_Xjq4pKjE_U7R5HEf-xc1TfVc/img.png?width=1245&coordinates=92%2C0%2C93%2C0&height=700" id="c2e6e" class="rm-shortcode" data-rm-shortcode-id="b58ca0abb324db9a0fd7851490615a89" data-rm-shortcode-name="rebelmouse-image" />
An illustration of a Spinosaurus skeleton with its thinner, more traditionally therapod-like tail.
A study of lost tails<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="0530ef75d9bc4d29b2bc7c7802ba98e9"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/fDhofM81RQE?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>But something was missing: a means of propulsion. How did a giant like Spinosaurus catch slick and quick prey while paddling like a duck on two stumpy hind legs? It didn't add up.</p><p>"The big thing we were missing was a propulsive structure because you can't really be an aquatic predator unless you have some way to catch prey in the water and move through the water," <a href="https://www.youtube.com/watch?v=fDhofM81RQE&t=66s" target="_blank">Ibrahim told <em>Nature</em></a>. "That's what we now found."</p><p>Between 2015 and 2019, on a grant from the National Geographic Society, Ibrahim and his team traveled to the Kem Kem region of the Moroccan Sahara to unearth further Spinosaurus fossils. During their dig, they discovered Spinosaurus tail vertebrae that were "characterized by extremely long spines."</p><p>Ibrahim's previous reconstruction of Spinosaurus featured a thin tail borrowed from other therapods. But such a tail would make traveling through the water unwieldy—think paddling a canoe with a walking stick. The new vertebrae revealed a fin-like tail, similar in appearance to a newt's, and could more easily propel the dinosaur through the water.</p><p>To test his hypothesis, Ibrahim's colleagues at Harvard crafted plastic models of the Spinosaurus tail. They attached it to a robot system that mimics swimming and measured its thrust and efficiency. They then compared the Spinosaurus tail's performance against two other therapod tails and extant aquatic animals.</p><p>Spinosaurus's results were consistent with the aquatic animals and superior to the terrestrial therapods. Ibrahim and his team published their results in <a href="https://www.nature.com/articles/s41586-020-2190-3" target="_blank"><em>Nature</em></a>. </p><p>"This discovery is the nail in the coffin for the idea that non-avian dinosaurs never invaded the aquatic realm," <a href="https://www.eurekalert.org/pub_releases/2020-04/ngs-nfr042920.php" target="_blank">Ibrahim said in a release</a>. "This dinosaur was actively pursuing prey in the water column, not just standing in shallow waters waiting for fish to swim by. It probably spent most of its life in the water."</p><p>But as is the case in science, not everyone is yet convinced.</p><p>Donald M. Henderson, the curator of dinosaurs at the Royal Tyrrell Museum, believes Spinosaurus likely lived at the water's edge, scooping up fish as they swam by. As he told <a href="https://www.nytimes.com/2020/04/29/science/spinosaurus-dinosaur-tail-swimming.html" target="_blank">the <em>New York Times</em></a>, he does not believe Spinosaurus would be a powerful swimmer.</p><p>"My first thing is, they haven't actually demonstrated that this tail could produce enough force to propel a six-and-a-half-ton body through the water," Henderson said. He added that the researchers had yet to provide that Spinosaurus had enough muscle power to move such a tail or compensate for the drag of its sail.</p>
Dinosaurs are alive! Here’s how we know, and why it matters<div class="rm-shortcode" data-media_id="nTfwl0kS" data-player_id="FvQKszTI" data-rm-shortcode-id="67c76febbfb51d2231c6bcef00459388"> <div id="botr_nTfwl0kS_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/nTfwl0kS-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/nTfwl0kS-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/nTfwl0kS-FvQKszTI.js"></script> </div> <p>As new fossils are found and new ideas to test emerge, we'll see if Henderson's concerns capsize the aquatic hypothesis or not.</p><p>Even if Spinosaurus is thrown out of the pool, that doesn't mean dinosaurs will forever remain grounded. As <a href="https://www.nytimes.com/2017/12/06/science/duck-dinosaur-swim.html?action=click&module=RelatedLinks&pgtype=Article" target="_blank">reported by the <em>New York Times</em></a>, a dinosaur fossil called <em>Halszkaraptor escuilliei</em> has features that suggest a partial aquatic lifestyle. These include "a neck like a swan, a snout like a goose, and forelimbs like flippers," but the specimen is so unusual that its authenticity remains a matter of debate. </p><p>And what is revealed in these debates will change our understanding of dinosaurs—both those that are gone and those that are still with us.</p>
New research on ankle exoskeletons show promising results.
- New research from Stanford finds that motor-powered ankle exoskeletons conserve 15 percent of energy expenditure when running.
- Spring-powered exoskeletons without motors actually made running harder.
- The researchers hope to develop better spring-powered models moving forward.
Stanford researchers find ankle exoskeleton makes running easier<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="5e8f155585a0bd7d072b36b8b6a96c39"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/NEIHLfPd4gI?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Mindset matters. Running is a birthright and offers great cardiovascular conditioning. Yet there has to be some excitement around it. As McDougall writes, "if you thought [running] was only a means to an end—an investment in becoming faster, skinnier, richer—then why stick with it if you weren't getting enough quo for your quid?"</p><p>You have to <em>love</em> running to dedicate yourself to it. If you're in pain, that's a tall order. </p><p>The researchers tested two modes of running assistance: motor-powered and spring-based exoskeletons. An exoskeleton is an external skeleton that supports an animal's body, such as insects and mollusks. In human terms, they are <a href="https://www.nextbigfuture.com/2018/05/suitx-lowers-cost-of-full-body-medical-mobility-exoskeleton-to-40000.html" target="_blank">expensive devices</a> designed to slow down fatigue. In this study, ankle exoskeletons were tethered to motors as volunteers ran on a treadmill. </p><p>Eleven competitive runners were divided into three groups: an "optimized power" group, the motor-based cohort that boosted the runners' strides; "optimized spring-like," the group wearing the exoskeleton sans motor power; and the control group, "zero torque mode," runners wearing an exoskeleton with none of the features initiated. A final control element was runners wearing a neutral running shoe with no exoskeleton.</p><p><br></p>
Optimized spring-like and Optimized powered assistance resulted in metabolic reductions of 2.1 and 24.7%, respectively, compared with zero-torque mode, while running at 2.7 m s−1. Optimized powered assistance resulted in an improvement in running economy of 14.6% compared with running in normal shoes, whereas Optimized spring-like assistance resulted in an 11.1% increase in the energy cost of running. Error bars indicate SD. *P < 0.05.
Kirby A. Witte, et al.<p>The motors are an important component. Wearing an exoskeleton with the motor switched off actually increased physical demand by 13 percent. With the motors purring, the demand was 15 percent less than when running without an exoskeleton.</p><p>Spring-based exoskeletons did not fare nearly as well, as it increased energy output by 11 percent than running without the gear. Stanford's Steve Collins, lead author of the paper, was surprised by this result, <a href="https://techxplore.com/news/2020-03-ankle-exoskeleton-aids.html" target="_blank">noting</a>,</p><p>"When people run, their legs behave a lot like a spring, so we were very surprised that spring-like assistance was not effective. We all have an intuition about how we run or walk but even leading scientists are still discovering how the human body allows us to move efficiently."</p>
(A) Exoskeleton emulator testbed. A participant runs on a treadmill while wearing bilateral ankle exoskeletons actuated by motors located off-board with mechanical power transmitted through flexible Bowden cables. (B) Ankle exoskeleton. The ankle exoskeleton attaches to the user by a strap above the calf, a rope through the heel of the shoe, and a carbon fiber plate embedded in the toe of the shoe. The inner Bowden cable terminates on a 3D printed titanium heel spur that is instrumented with strain gauges for direct measurement of applied torque. A magnetic encoder measures ankle angle. (C) Participant running on the treadmill with bilateral ankle exoskeletons. Metabolic data are collected through a respiratory system by measuring the oxygen and carbon dioxide content of the participant's expired gasses.
Kirby A. Witte, et al.<p>On the plus side, spring-based exoskeletons are much cheaper than motor-based models. The researchers are hoping to design a more energy-efficient model. Motor-powered models work great when tethered to treadmills but are unrealistic for road and trail runners, so an affordable spring-based version would be a boon for outdoor runners. </p><p>Spring-based exoskeletons mimic the natural spring of running. As with our normal running pattern, it stores energy only to unleash it when pushing off from the toes. With the help of a motor, the foot is able to extend at the ankle at the end of the step. Not quite Iron Man, but as Stanford graduate student <a href="https://techxplore.com/news/2020-03-ankle-exoskeleton-aids.html" target="_blank">Delaney Miller says</a> of these trials, </p><p style="margin-left: 20px;">"Powered assistance took off a lot of the energy burden of the calf muscles. It was very springy and very bouncy compared to normal running. Speaking from experience, that feels really good. When the device is providing that assistance, you feel like you could run forever."</p><p>Collins says this is one of the biggest improvements in energy economy ever made in running. It will likely not affect pro marathoners that much, but for novice runners or those susceptible to injury, it could ease the pain and remove a few seconds from your mile time. </p><p>Yes, humans were born to run. As it turns out, some of us just do it a little better with assistance. If consumer-priced exoskeletons hit the market, the statistics on running enthusiasts might swing in an upward direction. If the result is decreased energy expenditure, which by extension lowers the risk of injury, it's a win for all of us bipeds.</p><p>--<br></p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a> and <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a>. His next book is</em> "Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</p>
Scientists figured out how a certain treatment for skin cancer gives some patients a visual "superpower."
- In the early 2000s, it was reported that some cancer patients being treated with chlorin e6 were experiencing enhanced night vision.
- Using a molecular simulation, researchers discovered that a chlorin e6 injection under infrared light activates vision by changing retinal in the same way that visible light does.
- Researchers hope that this chemical reaction could one day be harnessed to help treat certain types of blindness and sensitivity to light.
In the early 2000s, it was reported that a certain kind of skin cancer treatment called photodynamic therapy, which uses light to destroy malignant cells, had a bizarre side effect: It was giving patients enhanced night time vision.An essential component to this therapy is a photosensitive compound called chlorin e6. Some people being treated with chlorin e6 were upset to discover that they were seeing silhouettes and outlines in the dark. Researchers think they might finally know why this happens.
The chemistry of vision
Rods and cones photoreceptors in a human retina.
Photo Credit: Dr. Robert Fariss, National Eye Institute, NIH / Flickr
"Seeing" happens when a series of receptors in the retina, the cones and rods, collect light. Rods contain a lot of rhodopsin, a photosensitive protein that absorbs visible light thanks to an active compound found in it called retinal. When retinal is exposed to visible light, it splits from rhodopsin. This then allows the light signal to be converted into an electrical signal that the visual cortex of our brains interprets into sight. Of course, there is "less light" at night, which actually means that light radiation is not in a domain visible to humans. It's at higher wavelengths (the infrared level) that retinal is not sensitive to. Hence, why we can't see in the dark like many critters can.
But the vision process can be activated by another interaction of light and chemistry. As it turns out, a chlorin e6 injection under infrared light changes retinal in the same way that visible light does. This is the cause of the unforeseen night vision side effect of the treatment."This explains the increase in night-time visual acuity," chemist Antonio Monari, from the University of Lorraine in France, told CNRS. "However, we did not know precisely how rhodopsin and its active retinal group interacted with chlorin. It is this mechanism that we have now succeeded in elucidating via molecular simulation."
"Molecular simulation" is a method that uses an algorithm that integrates the laws of quantum and Newtonian physics to model the functioning of a biological system over time. The team used this method to mimic the biomechanical movements of individual atoms – that is, their attraction or repulsion to one another – along with the making or breaking of chemical bonds.
"For our simulation we placed a virtual rhodopsin protein inserted in its lipid membrane in contact with several chlorin e6 molecules and water, or several tens of thousands of atoms," Monari explained to CNRS. "Our super-calculators ran for several months and completed millions of calculations before they were able to simulate the entire biochemical reaction triggered by infrared radiation." In nature, this phenomena occurs within fractions of a nanosecond.
The molecular simulation showed that when the chlorin e6 molecule absorbs the infrared radiation, it interacts with the oxygen present in the eye tissue and transforms it into reactive, or singlet, oxygen. In addition to killing cancer cells, "singlet oxygen" can also react with retinal to enable a slightly enhanced eyesight at night, when light waves are at the infrared level.
Now that researchers know why the "supernatural" side effect occurs, they may be able to limit the chance of it happening to patients undergoing photodynamic treatment. Thinking further out, the researchers hope for the possibility that this chemical reaction could be harnessed to help treat certain types of blindness and sensitivity to light.
Ultimately, researchers say that this has been a big flex for the power of molecular simulations, which can give us astonishing scientific insights like this.
"Molecular simulation is already being used to shed light on fundamental mechanisms – for example, why certain DNA lesions are better repaired than others – and enable the selection of potential therapeutic molecules by mimicking their interaction with a chosen target," Monari told CNRS.Don't hold your breath on night vision eyedrops though.
Scientists envision a new type of organism ready to assist humans.
- Computers designed, and scientists have constructed, programmable living robots.
- Study announces potentially self-healing, biodegradable, purpose-build automatons.
- Two "xenobots" are already bumbling their way around dishes of water in a lab.
How the xenobots are made and how they work<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjU3MDE1My9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NDE2OTAzMn0.AJanSX9G94Cndtejras7H7EKZaC-1tPe-vKH5b2riUI/img.jpg?width=980" id="0e351" class="rm-shortcode" data-rm-shortcode-id="44d828be88157339ed2f12c7fe269532" data-rm-shortcode-name="rebelmouse-image" />
Image source: Kriegman, Blackiston, Levin, and Bongard<p>The primary purpose of the research is the development of a workable, scalable pipeline that produces robots selected, or "programmed," for specific capabilities. It works like this:</p><p style="margin-left: 20px;"><em>Computer algorithms set to work iterating 500 to 1,000 virtual 3D structures using models of actual cells — whose behaviors are known — as building blocks. For the xenobots, models of passive and contractive (heart muscle) skin cells from frog embryos were used. Upon identifying designs that function in a desired manner, the scientists then painstakingly construct a real-world version using the actual, living cells.</em></p><p>In the case of the xenobots, the contractive skin muscles contract and expand, like an engine. Through this action, a xenobot can move itself around on a pumping pair of stumpy legs. One xenobot has a hole in its middle that's been formed into a pouch allowing it, theoretically, to carry a tiny payload of some sort. The xenobots can survive for about 10 days.</p>
The pipeline<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="41c4021fc413b0e3b21a1f8279789ce3"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/aQRBCCjaYGE?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Since the research is really about the pipeline, the xenobots are primarily intended as a demonstration of the system's potential. If you're wondering why we might <em>want</em> living robots, you're not alone. According to senior researcher roboticist <a href="https://www.uvm.edu/cems/cs/profiles/josh_bongard" target="_blank">Joshua Bongard</a>, "It's impossible to know what the applications will be for any new technology, so we can really only guess."</p><p>Even so, the researchers propose a few possible applications, including eating up and digesting microplastics in the ocean, and doing the same for toxins in the human body, delivering drugs to patients, and cleaning plaque from human artery walls.</p><p>All of these assume that the system can mature into a means of creating robots capable of performing multiple interlinked tasks such as identifying and then digesting toxins. If this becomes doable, there are some obvious benefits inherent in living-cell robots: They can heal themselves if the become damaged—this has already been demonstrated with the xenobots—and they are made of eminently biodegradable materials.</p>
Ethical and practical issues<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjU3MDE1NS9vcmlnaW4uZ2lmIiwiZXhwaXJlc19hdCI6MTYyMDg3Mzg0NX0.OFHGqFPQYF2T4RlVS_rB0WxNxXJIIERxYEksz2Jj9hs/img.gif?width=980" id="893b9" class="rm-shortcode" data-rm-shortcode-id="6e934d320465a1c295293042ce43be9f" data-rm-shortcode-name="rebelmouse-image" />
Image source: Kriegman, Blackiston, Levin, and Bongard<p>Chief among the ethical concerns regarding living robots is the notion that, as living organisms, the robots may be reasonably entitled to moral status as individuals.</p><p><a href="https://www.upstate.edu/bioethics/faculty-staff/fac_johnson.php" target="_blank">L. Syd M Johnson</a>, bioethicist at SUNY Upstate Medical University tells Big Think: "As with any new technology, how it is used or will be used raises important ethical concerns. As humans, we've shown time and again that we are really not good at predicting the future consequences of technological innovations. But when novel living organisms are created, I have concerns about potential harms to those organisms themselves. Humans have been creating and manipulating animals for millennia with little concern for how it affects the animals themselves. Will these xenobots be more like bacteria, which are alive, but not sentient, so we need not worry about their welfare? Or will they be more like jellyfish or corals, animals about whom we might reasonably wonder what they feel? In principle, xenobots are arguably animals, and could be created using neural cells, and to have a nervous system that would make it easier to "program" them to respond to and navigate the world. Releasing them into the world, and creating them to be potentially capable of feeling are both possibilities that I find worrying."</p><p>On a practical level, it's worth noting that among the possible uses mentioned by the researchers is an illustration of the type of problem the robots <em>couldn't</em> really solve. If they ate microplastics from the sea and then died, what would happen to their plastic-filled corpses? Wouldn't they eventually be eaten by other ocean organisms, merely shifting the plastic to a different rung in the ecological ladder? (Removing toxins from a human body would be less of an issue—the robot could simply be eliminated through the patient's digestive system.)</p>
Big picture<p> These concerns notwithstanding, the researchers remain excited by the possibilities, even beyond making living robots. "The aim is to understand the software of life," says Levin. "If you think about birth defects, cancer, age-related diseases, all of these things could be solved if we knew how to make biological structures, to have ultimate control over growth and form."</p>
A head built for meat-eating.
- A new analysis of fossils from the 1950s reveals an awesome predator.
- Pre-dating the dinosaurs, the erythrosuchids were voracious "hypercarnivores."
- Think terrifying crocodiles on steroids.
All in the ravenous family<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjI3ODAwNS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY0MjU0NTUyOH0.bajH7Dc7cdvFuO3JTCAiDUE_YnJcnbqm4W8dhMtO78A/img.png?width=980" id="33021" class="rm-shortcode" data-rm-shortcode-id="7372dd1e8e6e2748a5e4edf64c4fb34a" data-rm-shortcode-name="rebelmouse-image" />
An intriguingly odd species<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjI3ODAxMy9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYzNTA0NzcwOX0.XrNiSIFGbkHSK5Gu2OOmGNp50A6SPvRAnpbTyWWLQmo/img.png?width=980" id="3255b" class="rm-shortcode" data-rm-shortcode-id="1d3155e6521f8f1f49d638257eed0189" data-rm-shortcode-name="rebelmouse-image" />
Russian expedition carrying first erythrosuchid fossils
Image source: V.G. Ochev, from archive of M.A. Shishkin<p>The first <em> Garjainia</em> fossil was found in Russia in the 1950s, followed by <em> Vjushkovia triplicostata.</em> While previously assumed to be examples of two different species, they were later grouped together as <em>Garjainia prima.</em></p><p>Butler explained to NHM the appeal of erythrosuchids: "These are bizarre animals, but much about their biology remains unstudied. They presumably must have had very powerful neck muscles to support such a massive head, but detailed studies of their muscles have not yet been done." He adds, "There are lots of animals from this period of time that were bizarre and interesting but we don't know much about them at all."</p>