It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
IMAGE: SHARKS FOR SALE IN A SRI LANKAN FISH MARKET view more
CREDIT: CLAIRE COLLINS
Thousands of sharks have been illegally caught in a Marine Protected Area (MPA) in the Indian Ocean, new research shows.
The MPA was created in 2010 around the Chagos Archipelago, also known as the British Indian Ocean Territory (BIOT), banning all fishing there.
The new study examined information on illegal fishing in the MPA - a vast (640,000 km²/250,000 mi2) area containing pristine and remote reefs.
Enforcement data suggests more than 14,000 sharks were caught in the MPA from 2010-20, but discussions with fishers in the region suggest the true number was "considerably higher".
The study was carried out by the University of Exeter and ZSL (Zoological Society of London), Oceanswell and MRAG Ltd.
"Enforcement of MPA rules in a large, remote area such as this is extremely difficult," said lead author Claire Collins, of the University of Exeter.
"Our findings highlight the threat of illegal fishing to sharks in the BIOT MPA, which is home to critically endangered species such as the oceanic whitetip and scalloped hammerhead.
"Fishers often target reef areas, where many of the sharks are juveniles, and taking sharks at this life stage could be especially damaging to species numbers.
"However, it's important to note that - despite evidence of shark fishing - the MPA still provides a vital refuge in the Indian Ocean, and shark numbers there are still much higher than most other places.
"Many shark species in this region are under intense pressure from fishing.
"Following the recent news that the Maldives was considering lifting its shark-fishing ban, the importance of large areas within the Indian Ocean where shark fishing is banned was brought to everyone's attention.
"This study emphasises the need to ensure that sharks within these important areas are fully protected."
As part of the study, Oceanswell researchers carried out interviews and ran focus groups with fishers in two Sri Lankan communities previously associated with illegal fishing in the BIOT MPA.
Fishers told the researchers that vessels often fished in the MPA without being detected, providing "clear evidence that total extraction was considerably higher" than the estimate of 14,340 based on detected vessels, the study says.
"It is crucial to work with fishing communities to understand where, when and why people fish illegally - and how we can improve deterrence," said final author Tom B Letessier.
"For example, we found fishers had very different ideas of the fines they could face, and some felt there were very unlikely to be caught - so improving awareness of the sanctions, in addition to increasing the probability of being caught, could be beneficial."
Efforts are under way to improve enforcement in the MPA, including by increased use of satellite tracking of vessels and ensuring enforcement is responsive to the threat of illegal fishing.
This study highlights the value of interacting with fishers themselves to obtain information about the pressures they are facing and what motivates their behaviours.
Of the 188 vessels investigated by the BIOT MPA patrol boat from 2010-20, 126 were suspected of illegal fishing - and 97% of these targeted sharks.
More than three quarters of suspected vessels were from Sri Lanka, but a growing minority came from India - and these tended to be larger and could therefore take many more sharks.
"The threats to a large MPA like this one are constantly changing, so management of the MPA has to adapt too," Collins said.
The study was funded by grant ID is BPMS 2017-12 from the Bertarelli foundation, as part of the Bertarelli Programme of Marine Science.
The paper, published in the journal Frontiers in Marine Science, is entitled: "Understanding persistent non-compliance in a remote, large-scale marine protected area."
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Research results challenge a decades-old mechanism of how we hear sounds
IMAGE: PIERRE HAKIZIMANA, PRINCIPAL RESEARCH ENGINEER AT LINKÖPING UNIVERSITY view more
CREDIT: SANNA HEDIN
Researchers at Linköping University, Sweden, have made several discoveries on the functioning mechanisms of the inner hair cells of the ear, which convert sounds into nerve signals that are processed in the brain. The results, presented in the scientific journal Nature Communications, challenge the current picture of the anatomical organisation and workings of the hearing organ, which has prevailed for decades. A deeper understanding of how the hair cells are stimulated by sound is important for such matters as the optimisation of hearing aids and cochlear implants for people with hearing loss.
In order to hear sounds, we must convert sound waves, which are compressions and decompressions of air, into electrical nerve signals that are transmitted to the brain. This conversion takes place in the part of the inner ear known as the cochlea, due to its shape, which is reminiscent of a snail shell. The cochlear duct houses the hearing organ, with many hair cells that are divided into outer and inner hair cells. The outer hair cells amplify sound vibrations, which enables us to hear faint sounds and perceive the various frequencies in human speech better. The inner hair cells convert the sound vibrations into nerve signals. In the current study, the researchers have investigated how the conversion takes place. It is, namely, still unclear how the inner hair cells are stimulated by sound vibrations in order to produce nerve signals.
It has long been known that the outer hair cells are connected to a membrane that rests on top of them. The outer hair cells have hair-like protrusions known as stereocilia that are bent and activated when sound causes the membrane and the hearing organ to vibrate. However, the current view is that the stereocilia of the inner hair cells are not in contact with this membrane, which is known as the tectorial membrane, and that they are stimulated by sounds by a completely different mechanism. It is this model that the new study challenges.
The relationship between the hair cells and the tectorial membrane has been studied in detail by electron microscopy since the 1950s. But it is extremely difficult to investigate how this gelatinous membrane functions, since it shrinks as soon as it is removed from the ear. This makes it extremely difficult to preserve the relationship between the inner hair cells and the tectorial membrane. In addition, this membrane is transparent, and has therefore been essentially invisible. Until now. The LiU researchers noticed that the tectorial membrane reflected green light. This discovery made it possible to visualise the tectorial membrane by microscope.
"We cannot see any gap between the tectorial membrane and the hair cells. In contrast, the stereocilia on both outer and inner hair cells are completely embedded in the tectorial membrane. Our results are incompatible with the generally accepted idea that only the outer hair cells are in contact with the tectorial membrane", says Pierre Hakizimana, principal research engineer at the Department of Biomedical and Clinical Sciences at Linköping University, and principal author of the article.
Pierre Hakizimana and his colleagues have studied the inner ear of guinea pigs, which is very similar to that of humans. When the researchers investigated the relationship between the membrane and the hair cells in more detail, they made a further discovery.
"We found calcium ducts with an appearance that we've never seen before. These calcium ducts span the tectorial membrane and connect to the stereocilia of both the inner and the outer hair cells", says Pierre Hakizimana.
The research group, led by Professor Anders Fridberger, has previously discovered that the tectorial membrane functions as a reservoir for calcium ions, which are needed for the hair cells to convert the sound-evoked vibrations into nerve signals. The researchers followed the motion of the calcium ions in the ducts, and their results suggest that the calcium ions flow through the ducts to the hair cells. This may explain how the hair cells obtain the large amounts of calcium ions needed for their function. The study has also shown that the stereocilia on the inner and outer hair cells are bent by the tectorial membrane in similar ways. The next step of the research will be to understand in more detail how the calcium ions are transported, and identify the protein or proteins that make up the newly discovered calcium ducts.
"Our results allow us to describe a mechanism for how hearing functions, that is incompatible with the model that has been accepted for more than fifty years. The classic illustrations in the textbooks showing the hearing organ and how it functions must be updated. The mathematical models used in research to study hearing should also be updated to include these new findings", says Pierre Hakizimana.
New information about how our hearing functions may in the long term be important for the development of cochlear implants. These are hearing aids that are inserted into the cochlea and which use electrical stimulation to make it possible for children and adults with hearing loss to perceive sounds.
"Cochlear implants are an amazing solution for treating hearing loss, but they can be improved. A deeper understanding of how the inner hair cells are stimulated by sounds is important to optimise how cochlear implants stimulate the auditory nerve", says Pierre Hakizimana.
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The study has received financial support from the Tysta Skolan Foundation, the Swedish Research Council, and the National Institutes of Health in the US.
The article: "Inner hair cell stereocilia are embedded in the tectorial membrane", Pierre Hakizimana and Anders Fridberger, (2021), Nature Communications, published online on May 10, 2021, doi: 10.1038/s41467-021-22870-1 https://www.nature.com/articles/s41467-021-22870-1
How planets form controls elements essential for life
Rice scientists attribute Earth's nitrogen to rapid growth of moon- to Mars-sized bodies
IMAGE: NITROGEN-BEARING, EARTH-LIKE PLANETS CAN BE FORMED IF THEIR FEEDSTOCK MATERIAL GROWS QUICKLY TO AROUND MOON- AND MARS-SIZED PLANETARY EMBRYOS BEFORE SEPARATING INTO CORE-MANTLE-CRUST-ATMOSPHERE, ACCORDING TO RICE UNIVERSITY SCIENTISTS. IF METAL-SILICATE... view more
CREDIT: ILLUSTRATION BY AMRITA P. VYAS/RICE UNIVERSITY
HOUSTON - (May 10, 2021) - The prospects for life on a given planet depend not only on where it forms but also how, according to Rice University scientists.
Planets like Earth that orbit within a solar system's Goldilocks zone, with conditions supporting liquid water and a rich atmosphere, are more likely to harbor life. As it turns out, how that planet came together also determines whether it captured and retained certain volatile elements and compounds, including nitrogen, carbon and water, that give rise to life.
In a study published in Nature Geoscience, Rice graduate student and lead author Damanveer Grewal and Professor Rajdeep Dasgupta show the competition between the time it takes for material to accrete into a protoplanet and the time the protoplanet takes to separate into its distinct layers -- a metallic core, a shell of silicate mantle and an atmospheric envelope in a process called planetary differentiation -- is critical in determining what volatile elements the rocky planet retains.
Using nitrogen as proxy for volatiles, the researchers showed most of the nitrogen escapes into the atmosphere of protoplanets during differentiation. This nitrogen is subsequently lost to space as the protoplanet either cools down or collides with other protoplanets or cosmic bodies during the next stage of its growth.
This process depletes nitrogen in the atmosphere and mantle of rocky planets, but if the metallic core retains enough, it could still be a significant source of nitrogen during the formation of Earth-like planets.
Dasgupta's high-pressure lab at Rice captured protoplanetary differentiation in action to show the affinity of nitrogen toward metallic cores.
"We simulated high pressure-temperature conditions by subjecting a mixture of nitrogen-bearing metal and silicate powders to nearly 30,000 times the atmospheric pressure and heating them beyond their melting points," Grewal said. "Small metallic blobs embedded in the silicate glasses of the recovered samples were the respective analogs of protoplanetary cores and mantles."
Using this experimental data, the researchers modeled the thermodynamic relationships to show how nitrogen distributes between the atmosphere, molten silicate and core.
"We realized that fractionation of nitrogen between all these reservoirs is very sensitive to the size of the body," Grewal said. "Using this idea, we could calculate how nitrogen would have separated between different reservoirs of protoplanetary bodies through time to finally build a habitable planet like Earth."
Their theory suggests that feedstock materials for Earth grew quickly to around moon- and Mars-sized planetary embryos before they completed the process of differentiating into the familiar metal-silicate-gas vapor arrangement.
In general, they estimate the embryos formed within 1-2 million years of the beginning of the solar system, far sooner than the time it took for them to completely differentiate. If the rate of differentiation was faster than the rate of accretion for these embryos, the rocky planets forming from them could not have accreted enough nitrogen, and likely other volatiles, critical to developing conditions that support life.
"Our calculations show that forming an Earth-size planet via planetary embryos that grew extremely quickly before undergoing metal-silicate differentiation sets a unique pathway to satisfy Earth's nitrogen budget," said Dasgupta, the principal investigator of CLEVER Planets, a NASA-funded collaborative project exploring how life-essential elements might have come together on rocky planets in our solar system or on distant, rocky exoplanets.
"This work shows there's much greater affinity of nitrogen toward core-forming metallic liquid than previously thought," he said.
The study follows earlier works, one showing how the impact by a moon-forming body could have given Earth much of its volatile content, and another suggesting that the planet gained more of its nitrogen from local sources in the solar system than once believed.
In the latter study, Grewal said, "We showed that protoplanets growing in both inner and outer regions of the solar system accreted nitrogen, and Earth sourced its nitrogen by accreting protoplanets from both of these regions. However, it was unknown as to how the nitrogen budget of Earth was established."
"We are making a big claim that will go beyond just the topic of the origin of volatile elements and nitrogen, and will impact a cross-section of the scientific community interested in planet formation and growth," Dasgupta said.
CAPTION
Rice University geochemists analyzed experimental samples of coexisting metals and silicates to learn how they would chemically interact when placed under pressures and temperatures similar to those experienced by differentiating protoplanets. Using nitrogen as a proxy, they theorize that how a planet comes together has implications for whether it captures and retains volatile elements essential to life.
CREDIT
Tommy LaVergne/Rice University
Rice undergraduate intern Taylor Hough and research intern Alexandra Farnell, then a student at St. John's School in Houston and now an undergraduate at Dartmouth College, are co-authors of the study.
NASA grants, including one via the FINESST program, and a Lodieska Stockbridge Vaughn Fellowship at Rice supported the research.
https://news-network.rice.edu/news/files/2021/04/0405_NITRO-5-WEB.jpg Nitrogen-bearing, Earth-like planets can be formed if their feedstock material grows quickly to around moon- and Mars-sized planetary embryos before separating into core-mantle-crust-atmosphere, according to Rice University scientists. If metal-silicate differentiation is faster than the growth of planetary embryo-sized bodies, then solid reservoirs fail to retain much nitrogen and planets growing from such feedstock become extremely nitrogen-poor. (Credit: Illustration by Amrita P. Vyas/Rice University)
CAPTION
Rice University graduate student Damanveer Grewal, left, and geochemist Rajdeep Dasgupta discuss their experiments in the lab, where they compress complex mixtures of elements to simulate conditions deep in protoplanets and planets. In a new study, they determined that how a planet comes together has implications for whether it captures and retains the volatile elements, including nitrogen, carbon and water, essential to life.
CREDIT
Tommy LaVergne/Rice University
https://news-network.rice.edu/news/files/2021/03/0329_NITROGEN-1-WEB.jpg Rice University geochemists analyzed experimental samples of coexisting metals and silicates to learn how they would chemically interact when placed under pressures and temperatures similar to those experienced by differentiating protoplanets. Using nitrogen as a proxy, they theorize that how a planet comes together has implications for whether it captures and retains volatile elements essential to life. (Credit: Tommy LaVergne/Rice University)
https://news-network.rice.edu/news/files/2021/04/0405_NITRO-4-WEB.jpg Rice University graduate student Damanveer Grewal, left, and geochemist Rajdeep Dasgupta discuss their experiments in the lab, where they compress complex mixtures of elements to simulate conditions deep in protoplanets and planets. In a new study, they determined that how a planet comes together has implications for whether it captures and retains the volatile elements, including nitrogen, carbon and water, essential to life. (Credit: Tommy LaVergne/Rice University)
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,978 undergraduates and 3,192 graduate students, Rice's undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 1 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance.
In soil, high microbial fluctuation leads to more carbon emissions
Modeling shows fluctuating soil microbial populations impact how much carbon is released from soil
IMAGE: SAN DIEGO STATE UNIVERSITY ECOLOGISTS FOUND THAT SEASONAL FLUCTUATIONS IN TEMPERATURE LEAD TO A CORRESPONDING FLUCTUATION IN SOIL MICROBIAL POPULATIONS, AND INCREASED CARBON EMISSIONS. view more
CREDIT: SDSU
As humans, the weather where we live influences our energy consumption. In climates where weather shifts from hot summers to very cold winters, humans consume more energy since the body has to work harder to maintain temperature.
In much the same way, weather influences microbes such as bacteria and fungi in the soil. Seasonal fluctuations in soil temperature and moisture impact microbial activities that in turn impact soil carbon emissions and nutrient cycles.
Microbes consume carbon as the source of energy. As microbes increase in quantity and activities, they consume more carbon which results in more carbon emissions and vice versa.
In a modeling study published in Global Change Biology on May 10, San Diego State University ecologists found that this microbial seasonality has a significant impact on global carbon emissions and acts as a fundamental mechanism that regulates terrestrial-climate interactions and below ground soil biogeochemistry.
"When microbial colonies in the soil are in a productive phase, increasing in numbers and size, they will need more carbon to fuel their growth," said Xiaofeng Xu, global change ecologist and lead author. "When we manipulated the quantities and activities of soil microbes in simulations and observed the reciprocal changes in soil carbon, we found that when seasonal variation was removed, microbial respiratory rates went down."
By keeping the microbial population at a constant average level, carbon emissions can be reduced.
Stewards of the land could look at reducing fluctuation in soil microbial population by reducing tillage and other management practices in order to reduce soil carbon emissions, the researchers said. It can also help agricultural scientists and growers to sustain soil fertility
Using a microbial modeling framework -- CLM-Microbe (Community Land Model) -- developed in the Ecological Modeling and Integration Lab at SDSU where he studies how climate change impacts the terrestrial carbon cycle -- Xu and colleagues deployed the model on an SDSU supercomputer to reach this conclusion.
"We know soil microbes drive carbon flux -- the amount of carbon exchanged between land, ocean and atmosphere -- by producing enzymes that impact carbon flux," Xu said. "Soil carbon completes its cycle with the help of these microbes which have a hand in ultimate control of the carbon."
Different soil microbial groups play distinct roles in the carbon cycle.
"The model's ability to simulate bacterial and fungal dynamics improves our understanding of the soil microbial community's impact on the carbon cycle," said Liyuan He, first author and doctoral student at SDSU.
The finding advances soil microbial ecology and shows the ecological significance of microbial seasonality and our understanding of soil carbon storage under changing climate conditions.
The authors modeled and validated carbon fluxes observed at an individual plot scale in nine natural biomes including tropical/subtropical forest, temperate coniferous forest, temperate broadleaf forest, boreal forest, shrubland, grassland, desert, tundra, and wetland.
"This study demonstrates the need to incorporate microbial seasonality in earth system models so we can better predict climate-carbon interactions," said Chun-Ta Lai, co-author and an ecosystem ecologist at SDSU.
Next, the researchers will explore microbial seasonality and its impact on global carbon balance, given the dynamics of land use change around the world.
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The SDSU researchers also collaborated with senior staff scientist Melanie Mayes at Oak Ridge National Laboratory in Tennessee, and meteorologist Shohei Murayama with the National Institute of Advanced Industrial Science and Technology in Japan.
Funding sources for the study included the U.S Department of Energy Biological and Environmental Research Program and the CSU Program for Education & Research in Biotechnology.
Tweet and re-tweet: songbird stuttering allows researchers to pinpoint causes in the brain
Misfiring neurons in specific regions of the bird brain leads to stuttering patterns, and provides a model to explore treatments to restore normal speech
AUDIO: BRIEF SEQUENCE OF A NORMAL ZEBRA FINCH SONG view more
CREDIT: MIMI KAO, TUFTS UNIVERSITY
Speech problems such as stammering or stuttering plague millions of people worldwide, including 3 million Americans. President Biden himself struggled with stuttering as a child and has largely overcome it with speech therapy. The cause of stuttering has long been a mystery, but researchers at Tufts University are beginning to unlock its causes and a strategy to develop potential treatments using a very curious model system - songbirds. In a study published today in Current Biology, the researchers were able to observe that a simple, reversible pharmacological treatment in zebra finches can stimulate rapid firing in a part of the brain that leads to large variations in their song patterns, including the stuttering of short sequences of notes or syllables.
The part of the brain that appears to be linked to birdsong "re-tweeting" of syllables is the lateral magnocellular nucleus of the anterior nidopallium, or LMAN. When the LMAN is stimulated to fire its neurons in short rapid bursts, the birds start to "improvise" by varying the sequence of notes and tweeting a series of repetitions that share many similarities to stuttering in humans, including partial syllable repeats and abnormal pauses mid-sequence, followed by continuation to the next normal syllable after the repetition. Stuttering in syllable transitions can increase from 0.1% before treatment to as much as 13.6%. Typical frequency of stuttering in humans can occur in 4 - 8% of syllables.
The treatment used to induce LMAN to fire its neurons was a simple infusion of a drug, bicuculline methiodide (BMI), that acts on specific neuron receptors and ion channels. The changes in song patterns were observed to accumulate gradually over several days during infusion and can persist for weeks after treatment is stopped. Once the new song patterns are learned in the parts of their brain that control vocal motor activity, LMAN firing is no longer needed to drive them.
"We're excited about the work because it suggests that burst firing may be especially important for driving long-lasting changes in vocal sequences and may be one mechanism that can be targeted to restore normal vocal sequences," said Mimi Kao, assistant professor of biology at Tufts University and corresponding author of the study.
Earlier studies have evoked changes in song patterns not with a drug but by interrupting the auditory feedback by playing back white noise or a different song sequence. Rather than hearing just their own voice, the birds hear something different, and the mismatch causes them to alter the pitch, timing and sequence of syllables in their songs. It's like trying to sing Sinatra's "My Way" while someone is playing heavy metal in the background.
The pharmaceutical disruption of LMAN activity may be causing a similar alteration in auditory feedback to create variations and stuttering in song patterns. In both cases, removal of the disruption allows normal song patterns to return after a few days to weeks. And therein lies the hope for the treatment of speech dysfunction. If sustained aberrant firing patterns in LMAN or other regions of the brain can cause speech dysfunction, correction of those firing patterns could allow the brain to recover normal speech.
"Although the regions of the brain examined in this study have been known to be involved in speech dysfunctions, very little is known about the specific neuronal firing patterns involved," said Sanne Moorman, former postdoctoral fellow at Tufts University, currently at Utrecht University and first author of the study. "This research offers a way to manipulate the firing patterns, so we can learn how they contribute to dysfunctional speech and explore pharmaceutical or other treatments to recover normal function."
The implications of the research could reach further than speech pathology. Vocal performance is often affected in other basal ganglia movement disorders, such as Parkinson's disease and Huntington's disease, and may serve as a marker to quantify the effectiveness of therapeutic interventions in that region of the brain, according to the study authors.
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In the emptiness of space, Voyager I detects plasma 'hum'
ITHACA, N.Y. - Voyager 1 - one of two sibling NASA spacecraft launched 44 years ago and now the most distant human-made object in space - still works and zooms toward infinity.
The craft has long since zipped past the edge of the solar system through the heliopause - the solar system's border with interstellar space - into the interstellar medium. Now, its instruments have detected the constant drone of interstellar gas (plasma waves), according to Cornell University-led research published in Nature Astronomy.
Examining data slowly sent back from more than 14 billion miles away, Stella Koch Ocker, a Cornell doctoral student in astronomy, has uncovered the emission. "It's very faint and monotone, because it is in a narrow frequency bandwidth," Ocker said. "We're detecting the faint, persistent hum of interstellar gas."
This work allows scientists to understand how the interstellar medium interacts with the solar wind, Ocker said, and how the protective bubble of the solar system's heliosphere is shaped and modified by the interstellar environment.
Launched in September 1977, the Voyager 1 spacecraft flew by Jupiter in 1979 and then Saturn in late 1980. Travelling at about 38,000 mph, Voyager 1 crossed the heliopause in August 2012.
After entering interstellar space, the spacecraft's Plasma Wave System detected perturbations in the gas. But, in between those eruptions - caused by our own roiling sun - researchers have uncovered a steady, persistent signature produced by the tenuous near-vacuum of space.
"The interstellar medium is like a quiet or gentle rain," said senior author James Cordes, the George Feldstein Professor of Astronomy. "In the case of a solar outburst, it's like detecting a lightning burst in a thunderstorm and then it's back to a gentle rain."
Ocker believes there is more low-level activity in the interstellar gas than scientists had previously thought, which allows researchers to track the spatial distribution of plasma - that is, when it's not being perturbed by solar flares.
Cornell research scientist Shami Chatterjee explained how continuous tracking of the density of interstellar space is important. "We've never had a chance to evaluate it. Now we know we don't need a fortuitous event related to the sun to measure interstellar plasma," Chatterjee said. "Regardless of what the sun is doing, Voyager is sending back detail. The craft is saying, 'Here's the density I'm swimming through right now. And here it is now. And here it is now. And here it is now.' Voyager is quite distant and will be doing this continuously."
Voyager 1 left Earth carrying a Golden Record created by a committee chaired by the late Cornell professor Carl Sagan, as well as mid-1970s technology. To send a signal to Earth, it took 22 watts, according to NASA's Jet Propulsion Laboratory. The craft has almost 70 kilobytes of computer memory and - at the beginning of the mission - a data rate of 21 kilobits per second.
Due to the 14-billion-mile distance, the communication rate has since slowed to 160-bits-per-second, or about half a 300-baud rate.
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NASA, the Jet Propulsion Laboratory and the National Science Foundation supported the work. Cordes, Chatterjee and Ockler are members of Cornell's Carl Sagan Institute.
Wastewater treatment system recovers electricity, filters water
A dual-function electrode in a microbial fuel cell combines two previously separate functions
Whether wastewater is full of "waste" is a matter of perspective.
"Why is it waste?" asked Zhen (Jason) He, professor in the Department of Energy, Environmental & Chemical Engineering in the McKelvey School of Engineering at Washington University in St. Louis.
"It's organic materials," He said, and those can provide energy in a number of ways. Then there's the other valuable resource in wastewater.
Water.
He's lab has developed one system that recovers both, filtering wastewater while creating electricity. Results from bench-scale trials were published May 6 and featured as a front cover article in the journal Environmental Science: Water Research & Technology.
The waste materials in wastewater are full of organic materials which, to bacteria, are food.
"Bacteria love them and can convert them into things we can use," He said. "Biogas is the primary source of energy we can recover from wastewater; the other is bioelectricity."
There already exist ways to capitalize on bacteria to produce energy from wastewater, but such methods often do so at the expense of the water, which could be filtered and otherwise be used -- if not for drinking -- for "grey water" purposes such as irrigation and toilet flushing.
He's lab took the two processes -- filtration and energy production -- and combined them, integrating the filtration system into the anode electrode of a microbial electrochemical system.
The system is set up like a typical microbial fuel cell, a bacterial battery that uses electrochemically active bacteria as a catalyst where a traditional fuel cell would use platinum. In this type of system, the bacteria are attached to the electrode. When wastewater is pumped into the anode, the bacteria "eat" the organic materials and release electrons, creating electricity.
To filter that same water, however, requires a different system.
He's lab combined the systems, developing a permeable anode that acts as a filter.
The anode is a dynamic membrane, made of conductive, carbon cloth. Together, the bacteria and membrane filter out 80% to 90% of organic materials -- that leaves water clean enough to be released into nature or further treated for non-potable water uses.
He used a mixed culture of bacteria, but they had to share one feature -- the bacteria had to be able to survive in a zero-oxygen environment.
"If there was oxygen, bacteria would just dump electrons to the oxygen not the electrode," He said. "If you cannot respire with the electrode, you'll perish."
To find the correct bacteria, He mostly defers to nature.
"It's not 100 percent natural, but we select those that can survive in this condition," He said. "It's more like 'engineered selection,'" the bacteria that did survive and respire with the electrode were selected for the system.
The amount of electricity created is not enough to, say, power a city, but it is in theory enough to help to offset the substantial amount of energy used in a typical U.S. water treatment plant.
"In the U.S., about 3% to 5% of electricity is used for water and wastewater activity," He said. Considering the usage by a local municipal plant, He believes his system can reduce energy consumption significantly.
"Typically, the process consumes about 0.5 KWH of electricity per cubic meter," He said. Based on bench scale experiments, "We can reduce it by half, or more of that."
But the primary goal of He's system isn't electricity production, it's wastewater treatment and nutrient recovery.
"Bacteria can convert those organic materials into things we can use," He said. "We can also recover nutrients like nitrogen or phosphorus for fertilizer. We can use it to feed plants. It's only when we don't use it, then it becomes waste.
"Wastewater is a resource in the wrong location."
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This system helps robots better navigate emergency rooms
IMAGE: THE TEAM TRAINED THE ALGORITHM ON VIDEOS FROM YOUTUBE, MOSTLY COMING FROM DOCUMENTARIES AND REALITY SHOWS, SUCH AS "TRAUMA: LIFE IN THE ER " AND "BOSTON EMS. " THE SET OF... view more CREDIT: UNIVERSITY OF CALIFORNIA SAN DIEGO
Computer scientists at the University of California San Diego have developed a more accurate navigation system that will allow robots to better negotiate busy clinical environments in general and emergency departments more specifically. The researchers have also developed a dataset of open source videos to help train robotic navigation systems in the future.
The team, led by Professor Laurel Riek and Ph.D. student Angelique Taylor, detail their findings in a paper for the International Conference on Robotics and Automation taking place May 30 to June 5 in Xi'an, China.
The project stemmed from conversations with clinicians over several years. The consensus was that robots would best help physicians, nurses and staff in the emergency department by delivering supplies and materials. But this means robots have to know how to avoid situations where clinicians are busy tending to a patient in critical or serious condition.
"To perform these tasks, robots must understand the context of complex hospital environments and the people working around them," said Riek, who holds appointments both in computer science and emergency medicine at UC San Diego.
Taylor and colleagues built the navigation system, the Safety Critical Deep Q-Network (SafeDQN), around an algorithm that takes into account how many people are clustered together in a space and how quickly and abruptly these people are moving. This is based on observations of clinicians' behavior in the emergency department. When a patient's condition worsens, a team immediately gathers around them to render aid. Clinicians' movements are quick, alert and precise. The navigation system directs the robots to move around these clustered groups of people, staying out of the way.
"Our system was designed to deal with the worst case scenarios that can happen in the ED," said Taylor, who is part of Riek's Healthcare Robotics lab at the UC San Diego Department of Computer Science and Engineering.
The team trained the algorithm on videos from YouTube, mostly coming from documentaries and reality shows, such as "Trauma: Life in the ER" and "Boston EMS." The set of more than 700 videos is available for other research teams to train other algorithms and robots.
Researchers tested their algorithm in a simulation environment, and compared its performance to other state-of-the-art robotic navigation systems. The SafeDQN system generated the most efficient and safest paths in all cases.
Next steps include testing the system on a physical robot in a realistic environment. Riek and colleagues plan to partner with UC San Diego Health researchers who operate the campus' healthcare training and simulation center.
The algorithms could also be used outside of the emergency department, for example during search and rescue missions.
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Ph.D. student Sachiko Matsumoto and undergraduate student Wesley Xiao also contributed to the paper.
Social Navigation for Mobile Robots in the Emergency Department
Angelique M. Taylor, Sachiko Mastumoto, Wesley Xiao and Laurel Riek, University of California San Diego
IMAGE: GLACIAL LAKE IN THE HIMALAYAN REGION view more
CREDIT: LI HENG
An international team led by researchers from the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences and the University of Geneva has found that flash floods may triple across the Earth's "Third Pole" in response to ongoing climate change.
Their findings were published in Nature Climate Change on May 6.
The Hindu Kush-Himalaya, Tibetan Plateau and surrounding mountain ranges are widely known as the "Third Pole" of the Earth. It contains the largest number of glaciers outside the polar regions.
Due to global warming, the widespread and accelerated melting of glaciers over most of the Third Pole is causing rapid expansion and formation of glacial lakes. When water is suddenly released from these lakes through dam failure or overtopping, glacial lake outburst floods occur, posing a severe threat to downstream communities.
Despite the severe threat these extreme events pose for sustainable mountain development across the Third Pole, scientists are uncertain where and when such events are likely to occur.
In this study, the researchers focused on the threat from new lakes forming in front of rapidly retreating glaciers. They used satellite imagery and topographic modeling to establish the risk associated with about 7,000 glacial lakes now located across the Third Pole.
They found that one in six (1,203) of current glacial lakes pose a high to very high risk to downstream communities, most notably in the eastern and central Himalayan regions of China, India, Nepal, and Bhutan.
The researchers also systematically investigated past outburst flood events and hoped to find some patterns from them. Meanwhile, they used these events to validate their approaches. "We found that these approaches allowed us to accurately classify 96% of glacial lakes known to have produced floods in the past as high or very high risk. We can then apply them to future scenarios," said ZHENG Guoxiong from XIEG, one of the co-first authors of the study.
Under the highest emission scenario (sometimes referred to as the "business-as-usual" scenario), the study shows that much of the Third Pole may approach peak risk for glacial lake flooding by the end of the 21st century--or even by the middle of the century in some regions.
In addition to larger potential flood volumes resulting from the expansion of more than 13,000 lakes in the coming years, over time the lakes will grow closer to steep, unstable mountain slopes that may crash into lakes and provoke small tsunamis.
If global warming continues on its current path, the number of lakes classified as high or very high risk will increase from 1,203 to 2,963, with new risk hotspots emerging in the western Himalaya, Karakorum and parts of Central Asia. These regions have experienced glacial lake outburst floods before, but they have tended to be repetitive and linked to advancing glaciers.
The mountain ranges of the Third Pole span 11 nations, giving rise to potential transboundary natural disasters. The study shows that the number of future potential transboundary glacial flood sources could roughly double to a total of 902 lakes, with 402 of these lakes in the high and very high risk categories.
"Such disasters are sudden and highly destructive. Regular monitoring and assessment as well as early warning systems are important to prevent these floods," said Prof. BAO Anming from XIEG, a corresponding author of the study. "We hope this study will motivate relevant nations and the international community to work together to prevent future flood disasters in the Third Pole".
