The most famous mass extinction came from space, but the biggest might have been because of carbon dioxide. Cataclysms, whether the asteroid that ended the dinosaurs’ reign or the volcanism that may have caused the Great Dying, drove the first five mass extinctions in Earth’s history, in which 75 percent of more of the planet’s life died out. The sixth mass extinction may now be beginning—and the apocalypse this time is us. During the last several centuries we have burned through eons worth of fossilized sunshine, changing the climate for our fellow species. We use more than half of the planet’s unfrozen land for cities, logging or food, eliminating the habitats of our fellow animals and plants. Before we even achieved civilization, we had already helped hunt the biggest, fiercest animals—woolly mammoths, giant kangaroos and giant sloths—to extinction. Biologists and paleoecologists estimate that humans have driven roughly 1,000 species extinct in our 200,000 years on the planet. Since 1500 we have killed off at least 322 types of animals, including the passenger pigeon, the Tasmanian tiger and, most recently, the baiji, a freshwater dolphin in China. Another 20,000 or more species are now threatened with extinction according to the International Union for the Conservation of Nature, which keeps a list of all the known endangered plants and animals on the planet. The population of any given animal among the five million or so species on the planet is, on average, 28 percent smaller, thanks to humans. And as many as one third of all animals are either threatened or endangered, a new study in Science finds.
Humans will have a chance to prove their adaptability as the Earth undergoes unprecedented challenges in the Anthropocene, an era named after our impact on the biosphere. To learn what it takes to survive far into the future, astrobiologist David Grinspoon interviewed Kim Stanley Robinson, a writer regarded as one of the most important science fiction and political novelists alive today. Robinson’s recent book, 2312, permits humans to survive near-extinction and populate the solar system over the course of 300 years. We decided to kick off the conversation with a 2312 excerpt from the chapter, “Earth, The Planet of Sadness:” “Clean tech came too late to save Earth from the catastrophes of the early Anthropocene. It was one of the ironies of their time that they could radically change the surfaces of the other planets, but not Earth. The methods they employed in space were almost all too crude and violent. Only with the utmost caution could they tinker with anything on Earth, because everything there was so tightly balanced and interwoven.”
New study reveals rat’s remorse — another way other animals are like humans
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What’s the difference between you and a rat? The list is unsurprisingly long but now, we can cross a universal human experience — feelings of regret — off of it. A new study shows for the first time that rats regret bad decisions and learn from them. In addition to existentialist suggestions of a rat’s regret — and what that takes away from, or adds to, being “human” — the study is highly relevant to basic brain research. Researchers demonstrated that we can tap into complex internal states of rodents if we hone in on the right behavior and the right neurons. There is a significant literature on what brain regions are representative of certain states, like reward predictions and value calculations, but the study, powered by a novel behavioral test, is able to put together such discrete behavioral correlates into a “rat” definition of regret. Finding better animal models of human behavior constitute a long-standing challenge in neuroscience: It has been difficult to authentically recapitulate mental states in animal models of neuropsychiatric disorders: For example, an attempt to model depression in rodents can often go no further than relatively coarse approximations of the core symptoms like guilt or sadness, which often translates to behaviors like social avoidance or anhedonia in rodents. The inability to efficiently approach the questions of mental abnormalities is a major problem. Depression is currently ranked as the leading cause of disability globally, and it’s estimated that by 2020, depression will lead 1.5 million people to end their lives by suicide.
Terrence Sejnowski, Professor and Laboratory Head of the Computational Neurobiology Laboratory (credit: Salk Institute for Biological Studies) In a study
In a study published July 28 in the Proceedings of the National Academy of Sciences, Salk Institute for Biological Sciences researchers have found that brain cells called astrocytes — not neurons — can control the brain’s gamma waves.
They also found that astrocytes — a type of glial cell traditionally thought to provide more of a support role in the brain — and the gamma oscillations they help shape are critical for some forms of memory, such as object recognition.
(When you’re expecting something or when something captures your interest, unique high-frequency electrical rhythms called gamma waves sweep through your brain. Gamma waves have been associated with higher-level brain function, and disturbances in the patterns have been tied to schizophrenia, Alzheimer’s disease, autism, epilepsy and other disorders.)
Evidence linking gamma waves with attention and memory, influenced by astrocytes
“This is what could be called a smoking gun,” says co-author Terrence Sejnowski, head of the Computational Neurobiology Laboratory at the Salk Institute for Biological Sciences, a Howard Hughes Medical Institute investigator. “There are hundreds of papers linking gamma oscillations with attention and memory, but they are all correlational. This is the first time we have been able to do a causal experiment, where we selectively block gamma oscillations and show that it has a highly specific impact on how the brain interacts with the world.”
A collaboration among the labs of Salk professors Sejnowski, Inder Verma, and Stephen Heinemann found that activity in the form of calcium signaling in astrocytes immediately preceded gamma oscillations in the brains of mice. This suggested that astrocytes, which use many of the same chemical signals as neurons, could be influencing these oscillations.
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An international team of researchers led by the University of Arizona (UA) has sequenced the complete genome of African rice. The genetic information will enhance scientists’ and agriculturalists’ understanding of the growing patterns of African rice, and help development of new rice varieties that are better able to cope with increasing environmental stressors to help solve global hunger challenges, the researchers say. The research paper was published in Nature Genetics (open access). The 9 billion-people question “Rice feeds half the world, making it the most important food crop,” said Rod A. Wing, director of the Arizona Genomics Institute at the UA . “Rice will play a key role in helping to solve what we call the 9-billion-people question.” The 9 billion-people question refers to predictions that the world’s population will increase to more than 9 billion people — many of whom will live in areas where access to food is extremely scarce — by the year 2050. The question lies in how to grow enough food to feed the world’s population and prevent the host of health, economic and social problems associated with hunger and malnutrition. Now, with the completely sequenced African rice genome, scientists and agriculturalists can search for ways to cross Asian and African species to develop new varieties of rice with the high-yield traits of Asian rice and the hardiness of African rice. “African rice is once more at the forefront of cultivation strategies that aim to confront climate change and food availability challenges,” said Judith Carney, a professor in the Department of Geography and the Institute of the Environment and Sustainability at the University of California, Los Angeles, and author of “Black Rice.” The book describes the historical importance of African rice, which was brought to the United States during the period of transatlantic slavery. Carney is also a co-author on the Nature Genetics paper, and her book served as one of the inspirations behind sequencing the African rice genome.
Broody octopus keeps record-breaking four-year vigil
For four years and five months, she clung to the rock and guarded her eggs. In a feat that surely made good use of all eight arms, an octopus revealed a new secret of deep sea life when ecologists observed her record-breaking behaviour from a robotic submarine. This doubles the longest brooding time ever seen in the animal kingdom, giving embryos time to develop in the cold. The discovery, published in the journal PLOS One, was made in a canyon 1.4km beneath the Pacific, off California. Dr Bruce Robison led the research at the Monterey Bay Aquarium Research Institute (MBARI). He told BBC News his team had stumbled upon the plucky mother in the days before she settled down and glued her eggs to the rock face. She was heading, slowly, for a known brooding site. By looking at characteristic scars in one of her eight armpits, the team identified the same octopus on the next dive, one month later. (via BBC News - Broody octopus keeps record-breaking four-year vigil)
'Quantum Cheshire Cat' becomes reality
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Scientists have for the first time separated a particle from one of its physical properties - creating a “quantum Cheshire Cat”. The phenomenon is named after the curious feline in Alice in Wonderland, who vanishes leaving only its grin. Researchers took a beam of neutrons and separated them from their magnetic moment, like passengers and their baggage at airport security. They describe their feat in Nature Communications. The same separation trick could in principle be performed with any property of any quantum object, say researchers from Vienna University of Technology. Their technique could have a useful application in metrology - helping to filter out disturbances during high-precision measurements of quantum systems.
Schrodinger’s paradox In Lewis Carroll’s classic children’s story, the Cheshire Cat gradually disappears, leaving only its mischievous grin. This prompts Alice to exclaim: “Well! I’ve often seen a cat without a grin, but a grin without a cat! It’s the most curious thing I ever saw in my life!” The idea of a “quantum Cheshire Cat” was first proposed in 2010 by Dr Jeff Tollaksen from Chapman University, a co-author on this latest paper. In the world familiar to us, an object and its properties are always bound together. A rotating ball, for instance, cannot become separated from its spin. (via BBC News - ‘Quantum Cheshire Cat’ becomes reality)
An artificial leaf converts water and light to oxygen, and that’s good news for road-tripping to places beyond Earth.
One of the persistent challenges of manned space exploration is that pesky lack of oxygen throughout much of the universe. Here on Earth, trees and other plant life do us a real solid by taking in our bad breath and changing it back to clean, sweet O2.
So what if we could take those biological oxygen factories into space with us, but without all the land, sun, water, soil, and gravity that forests tend to require? This is the point where NASA and Elon Musk should probably start paying attention.
Royal College of Art graduate Julian Melchiorri has created the first man-made, biologically functional leaf that takes in carbon dioxide, water, and light and releases oxygen. The leaf consists of chloroplasts — the part of a plant cell where photosynthesis happens — suspended in body made of silk protein.
"This material has an amazing property of stabilizing (the chloroplast) organelles," Melchiorri says in the video below. "As an outcome I have the first photosynthetic material that is living and breathing as a leaf does."
In addition to its potential value to space travel, Melchiorri also imagines the technology literally providing a breath of fresh air to indoor and outdoor spaces here on Earth. The facades of buildings and lampshades could be made to exhale fresh air with just a thin coating of the leaf material.
But perhaps best of all, a man-made breathing leaf could be the key to not just space travel but space colonization. No need to figure out how to till that dry, red Martian dirt to get some nice leafy trees to grow; we could just slap them on the inside of the colony’s dome and puff away.
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