Hexbyte Glen Cove More trees do not always create a cooler planet, geographer finds thumbnail

Hexbyte Glen Cove More trees do not always create a cooler planet, geographer finds

Hexbyte Glen Cove

Forest conversion from 1986 to 2000. Percentage of forest pixels converted, mapped at a 990 m x 990 m resolution. All cities with a population greater than 250,000 are displayed as black dots. Credit: Clark University Professor Christopher A. Williams

New research by Christopher A. Williams, an environmental scientist and professor in Clark University’s Graduate School of Geography, reveals that deforestation in the U.S. does not always cause planetary warming, as is commonly assumed; instead, in some places, it actually cools the planet. A peer-reviewed study by Williams and his team, “Climate Impacts of U.S. Forest Loss Span Net Warming to Net Cooling,” published today (Feb. 12) in Science Advances. The team’s discovery has important implications for policy and management efforts that are turning to forests to mitigate climate change.

It is well established that forests soak up from the air and store it in wood and soils, slowing the accumulation of greenhouse gases in the atmosphere; however, that is not their only effect on . Forests also tend to be darker than other surfaces, said Professor Williams, causing them to absorb more sunlight and retain heat, a process known as “the albedo effect.”

“We found that in some parts of the country like the Intermountain West, more forest actually leads to a hotter planet when we consider the full climate impacts from both and albedo effects,” said Professor Williams. It is important to consider the albedo effect of forests alongside their well-known carbon storage when aiming to cool the planet, he adds.

The research was funded by two grants from NASA’s Carbon Monitoring System. Williams and his research team—comprising data scientist Huan Gu, Ph.D. from The Climate Corporation and Tong Jiao, Ph.D.—found that for approximately one quarter of the country, forest loss causes a persistent net cooling because the albedo effect outweighs the carbon effect. They also discovered that loss of forests east of the Mississippi River and in Pacific Coast states caused planetary warming, while forest loss in the Intermountain and Rocky Mountain West tended to lead to a net cooling.

According to Professor Williams, scientists have known for some time that expanding forest cover cannot be assumed to cool the planet or to mitigate global warming. However, this has not always been appreciated broadly.

“If we fail to consider both the carbon and the albedo effects, large-scale tree-planting initiatives, such as Canada’s 2Billion Trees Initiative and The Nature Conservancy’s Plant a Billion Trees campaign, could end up placing trees in locations that are counterproductive for cooling the climate system,” said Professor Williams.

“It is all about putting the right trees in the right place,” said Williams, “and studies like ours can help identify where the potential for cooling is greatest.”

Every year, approximately one million acres of forest are being converted to non-forest areas across the lower 48 states of the U.S.; this is largely due to suburban and exurban expansion and development. Professor Williams’ team found that the net climate impact of a full 15 years of forest losses amounts to about 17% of a single year of U.S. fossil fuel emissions.

Clark University Professor Christopher A. Williams. Credit: Photographer Steven King

Williams’ research team used state-of-the-art satellite remote sensing to bring a detailed, observational perspective to examine this problem that had previously been assessed mostly with computer models. The three researchers pinpointed the locations of forest loss and identified what those sites became—urban, agricultural, grassland, shrubland, pasture, or something else. They then quantified how much biomass carbon was released to the atmosphere, and how much additional sunlight was reflected out to space. By comparing these two effects they measured the net impact of deforestation on the climate system.

The new datasets and methods used in Professor Williams’ study show that the tools are available to take the albedo effect into account. The Clark team hopes to generate actionable datasets to share with land managers and policymakers worldwide within the next one or two years, to help ensure that their tree-planting efforts focus on the right places and have the intended effects.



More information:
“Climate impacts of U.S. forest loss span net warming to net cooling” Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.aax8859

Provided by
Clark University

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More trees do not always create a cooler planet, geographer finds (2021, February 12)
retrieved 14 February 2021
from https://phys.org/news/2021-02-trees-cooler-planet-geographer.html

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Hexbyte Glen Cove Study: Humpback whales aren't learning their songs from one another thumbnail

Hexbyte Glen Cove Study: Humpback whales aren’t learning their songs from one another

Hexbyte Glen Cove

Credit: CC0 Public Domain

Humpback and bowhead whales are the only mammals other than humans thought to progressively change the songs they sing through a process of cultural learning.

But maybe the humpbacks are no longer part of that trio. Humpbacks might be singing songs that are not as ‘cultured’ as once assumed.

A new study by a University at Buffalo researcher is directly contradicting the widely accepted cultural transmission hypothesis suggesting that learn their songs from other whales.

“It seems like that is not correct,” says Eduardo Mercado, a professor of psychology in UB’s College of Arts and Sciences. “Our findings indicate that neither cultural transmission nor contributes significantly to how change their songs over time.

“I think the results are provocative and will probably make other whale researchers livid or dismissive, but at least the discussion won’t be boring!”

The study, published Tuesday (Feb. 9) in the Journal of Comparative Psychology, analyzed songs from groups of humpbacks that were not in acoustic contact with each other, yet still produced acoustically comparable songs.

“The idea that humpback whales are a distinguished part of the animal kingdom because of their ability to culturally learn songs is apparently not true,” says Mercado. “But to me, what the whales are doing is actually more impressive.

“Cultural transmission implies that what’s heard is copied. That means it doesn’t matter what is heard or what is copied. But what we found is very specific and precise, without a trace of arbitrary vocalization. The songs change over time in a fashion that’s even more precise than what humans do when language develops.”

The talented club DJ serves as an appropriate metaphor for changing whale .

“DJs can’t just randomly go from one song to the next,” says Mercado. “They have to think about beat matching, tempo and mood in order to maintain a continuous flow.

“I think that might be true of the whales. When they make changes, they do so in relation to what preceded it. They’re basically beat matching when they change songs—and we found similarities in populations that had no social contact or genetic links.”

Mercado says existing research claims that humpback populations isolated from one another do not change their songs in the same way. Each population is original, taking their songs in original directions.

“These things are not true,” says Mercado. “I compare songs over 40 years and compare populations that have never been in contact with one another, and they’re doing basically the same thing.”

Despite large and sometimes rapid changes, whales often end up singing similar songs, according to Mercado. The cultural transmission hypothesis is attractive in part because it’s hard to imagine what mechanism might instigate the song variation.

But previous research has relied heavily on subjectively defined categories. Songs sounding like a human snore would be placed in a “snore” category. Any subsequent analysis would depend on how well the categories captured the intricacies of the song.

“I didn’t categorize things at all and used purely acoustic measurements,” says Mercado, who specifically chose published records of data to avoid any suggestion of cherry picking the data. “This paper is based on direct measurements of sound features without any categorization or subjective labeling.”

Mercado says the results of the current study question the role of vocal imitation and cultural transmission in whale song, but they do not resolve why the songs are changing.

“These results tell me that whales are sophisticated in ways that researchers and observers hadn’t previously considered,” says Mercado. “What we’re hearing is a level of acoustic sophistication which is beyond the ability of humans.

“That’s something that deserves both appreciation and further study. I’d like to examine why whale song changes and explore the benefit of that change.”



More information:
Eduardo Mercado et al, Similarities in composition and transformations of songs by humpback whales (Megaptera novaeangliae) over time and space., Journal of Comparative Psychology (2021). DOI: 10.1037/com0000268

Citation:
Study: Humpback whales aren’t learning their songs from one another (2021, February 12)
retrieved 14 February 2021

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Hexbyte Glen Cove Dutch get their skates on in Amsterdam before the thaw thumbnail

Hexbyte Glen Cove Dutch get their skates on in Amsterdam before the thaw

Hexbyte Glen Cove

by Mike Corder

Dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)

Dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal Saturday as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018.

People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. One man even slithered across the ice on a skateboard deck without the wheels.

“Fantastic, and especially nowadays it’s a once-every-so-many-years experience, so when you get the chance, do it,” said Marc Burkett as he laced up his skates before taking to the canal.

It was the first time since 2018 that skating was possible on the .

Elsewhere in the country the ice was safer. People flocked to frozen lakes and canals to enjoy the conditions before a thaw forecast to begin in coming days. Parents pulled children in sleds, youngsters played hockey, even dogs took to the ice.

The country’s skating association and called on people to go to ice close to their homes to avoid overcrowding at popular lakes that would prevent social distancing amid the country’s tough coronavirus lockdown.

But many people still sought to drive to their favorite skating location. Car parks at the picturesque Kinderdijk windmills were full by 7:30 a.m., local broadcaster Rijnmond reported.

  • Dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Mike Corder)
  • Dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • Dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • Dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • Dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • Dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • Two men propose a toast as dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • A man puts on his skates as dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • Dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • A man puts on his skates as dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • A man puts on his skates as dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)
  • A man puts on his skates as dozens of skaters took to the frozen surface of Amsterdam’s historic Prinsengracht canal in Amsterdam, Netherlands, Saturday, Feb. 13, 2021, as the deep freeze gripping Europe briefly made it possible to skate on a small section of the canal for the first time since 2018. People skated and walked on a small stretch of ice between two bridges close to the landmark Westerkerk before growing cracks in the ice forced all but the most daring off the ice. in Amsterdam, Netherlands, Saturday, Feb. 13, 2021. (AP Photo/Patrick Post)

“Kinderdijk is full,” the local municipality tweeted.

Arguably the greatest skating event of them all, the roughly 200-kilometer (125 mile) 11 Cities Tour in the northern province of Friesland is a non-starter this year even if the ice is strong enough to hold some 25,000 competitors. Organizers have ruled it out amid the current lockdown.

Christopher Talvitie, who lives in Amsterdam, showed off some sharp skating skills on his hockey , weaving fast in between less experienced skaters.

“I’m from Finland myself so we first learn to walk and then the next thing we learn to skate. Like, it’s in the blood,” he said.

He was among the first on the ice and the last off it.

“It’s a perfect day, it’s a dream come true,” he said.



© 2021 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.

Citation:
Dutch get their skates on in Amsterdam before the thaw (2021, February 13)
retrieved 13 February 2021
from https://phys.org/news/2021-02-dutch-skates-amsterdam.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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Hexbyte Glen Cove Image: Hubble takes portrait of nebula thumbnail

Hexbyte Glen Cove Image: Hubble takes portrait of nebula

Hexbyte Glen Cove

Credit: ESA/Hubble & NASA, L. Stanghellini

This image from the NASA/ESA Hubble Space Telescope features an impressive portrait of M1-63, a beautifully captured example of a bipolar planetary nebula located in the constellation of Scutum (the Shield).

A nebula like this one is formed when the star at its center sheds huge quantities of material from its outer layers, leaving behind a spectacular cloud of gas and dust. 

It is believed that a binary system of at the center of the bipolar is capable of creating hourglass or butterfly-like shapes like the one in this image.

This is because the material from the shedding star is funneled toward its poles, with the help of the companion, creating the distinctive double-lobed structure seen in nebulae such as M1-63.



Citation:
Image: Hubble takes portrait of nebula (2021, February 13)
retrieved 13 February 2021
from https://phys.org/news/2021-02-image-hubble-portrait-nebula.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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Hexbyte Glen Cove InSight is meeting the challenge of winter on dusty Mars thumbnail

Hexbyte Glen Cove InSight is meeting the challenge of winter on dusty Mars

Hexbyte Glen Cove

This illustration shows NASA’s InSight spacecraft with its instruments deployed on the Martian surface. Credit: NASA/JPL-Caltech

As dust collects on the solar panels and winter comes to Elysium Planitia, the team is following a plan to reduce science operations in order to keep the lander safe.

NASA’s InSight lander recently received a mission extension for another two years, giving it time to detect more quakes, , and other phenomena on the surface of Mars. While the mission team plans to continue collecting data well into 2022, the increasing dustiness of the spacecraft’s and the onset of the Martian winter led to a decision to conserve and temporarily limit the operation of its instruments.

InSight was designed to be long-lasting: The stationary lander is equipped with solar panels, each spanning 7 feet (2 meters) across. InSight’s design was informed by that of the solar-powered Spirit and Opportunity rovers, with the expectation that the panels would gradually reduce their as settled on them but would have ample output to last through the two-year prime mission (completed in November 2020).

Additionally, InSight’s team chose a landing site in Elysium Planitia, a windswept plain on the Red Planet’s equator that receives lots of sunlight. It was hoped that passing dust devils might clean off the panels, which happened many times with Spirit and Opportunity, allowing them to last years past their design lifetime.

But despite InSight detecting hundreds of passing dust devils, none has been close enough to clean off those dinner-table-size panels since they unfurled on Mars in November 2018. Today, InSight’s solar arrays are producing just 27% of their dust-free capacity. That power has to be shared between science instruments, a robotic arm, the spacecraft’s radio, and a variety of heaters that keep everything in working order despite subfreezing temperatures. Since the windiest season of the Martian year has just ended, the team isn’t counting on a cleaning event in the coming months.

Mars is currently moving toward what’s called aphelion, the point in its orbit when it’s farthest away from the Sun. That means the already-weak sunlight on the Martian surface is growing even fainter, reducing power when InSight most needs its heaters to stay warm. Mars will start approaching the Sun again in July 2021, after which the team will begin to resume full .

“The amount of power available over the next few months will really be driven by the weather,” said InSight’s project manager, Chuck Scott of NASA’s Jet Propulsion Laboratory in Southern California. “As part of our extended-mission planning, we developed an operations strategy to keep InSight safe through the winter so that we can resume science operations as solar intensity increases.” JPL leads the InSight mission, though the spacecraft and its solar panels were built by Lockheed Martin Space of Denver, Colorado.

Over the coming weeks and months, InSight scientists will be carefully selecting which instruments need to be switched off each day to preserve power for heaters and energy-intensive activities like radio communication. InSight’s weather sensors are likely to remain off much of the time (resulting in infrequent updates to the mission’s weather page), and all the instruments will have to be powered off for some period around aphelion.

Currently, power levels look strong enough to take the lander through the winter. But solar power generation on Mars is always a little uncertain. The Opportunity rover was forced to shut down after a series of dust storms darkened the Martian sky in 2019, and Spirit did not survive the Martian winter in 2010. If InSight were to run out of power due to a sudden dust storm, it is designed to be able to reboot itself when the sunlight returns if its electronics survived the extreme cold.

Later this week, InSight will be commanded to extend its robotic arm over the panels so a camera can take close-up images of the dust coating. Then the team will pulse the motors that unfurled each panel after landing to try to can disturb the dust and see if the wind blows it away. The team considers this to be a long shot but worth the effort.

“The InSight team has put together a strong plan to safely navigate through winter and emerge on the other side ready to complete our extended science mission through 2022,” said Bruce Banerdt of JPL, InSight’s principal investigator. “We’ve got a great vehicle and a top-notch team; I’m looking forward to many more new discoveries from InSight in the future.”



Citation:
InSight is meeting the challenge of winter on dusty Mars (2021, February 13)
retrieved 13 February 2021

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Hexbyte Glen Cove Epidemic possibly caused population collapse in Central Africa 1400-1600 years ago thumbnail

Hexbyte Glen Cove Epidemic possibly caused population collapse in Central Africa 1400-1600 years ago

Hexbyte Glen Cove

In search of evidence for the first settlements of Bantu speakers south of the Congo rainforest: archeological excavations in Mukila (Kwango Province, DR Congo) as part of the BantuFirst-project. Credit: © Dirk Seidensticker 2018

A new study published in the journal Science Advances shows that Bantu-speaking communities in the Congo rainforest underwent a major population collapse from 1600 to 1400 years ago, probably due to a prolonged disease epidemic, and that significant resettlement did not restart until around 1000 years ago. These findings revise the population history of no less than seven present-day African countries (Cameroon, Central African Republic, Democratic Republic of the Congo, Republic of the Congo, Gabon, Equatorial Guinea, and Angola) and challenges the commonly held belief that the settlement of Central Africa by Bantu-speaking communities was a continuous process from about 4000 years ago until the start of the transatlantic slave trade.

Ongoing debates about decolonization, restitution of African cultural heritage and antiracism have also renewed interest in the European colonization of Central Africa, even if it was a relatively short period in the long and eventful history of the region. Modern humans lived in the savannas of Central Africa several tens of thousands of years before they emerged in Europe. Also, in the Congo rainforest did our ancestors overcome many challenges long before the first European expedition traversed it, as shown again in this recently published study.

Unique interdisciplinary research method

As part of a cross-disciplinary research project examining the interconnections between human migration, language spread, climate change and early farming in pre-colonial Central Africa, the current study combines a comprehensive analysis of all available archeological radiocarbon dates as a proxy for human activity and demographic fluctuation with a comprehensive analysis of the diversity and distribution of pottery styles as a proxy for socio-economic development. These well-dated archeological records were further compared in this study with genetic and to gain new insights into the ancient settlement history of Bantu-speaking populations in the Congo rainforest.

According to archeologist Dirk Seidensticker (UGent), one of the two lead authors, the multi-proxy approach developed in this study is unique both in terms of empirical evidence and scientific method, in that it uses 1149 radiocarbon dates linked to 115 pottery styles recovered from 726 sites throughout the Congo rainforest and adjacent areas: “We are the first to integrate these three types of archeological datasets on such a large scale and for such a long period and to demonstrate that throughout Central Africa two periods of more intense human activity (~800 BCE to 400 CE and ~1000 to 1900 CE) are separated by a widespread population collapse between 400 and 600 CE. Doing so, we could clearly delineate the periods commonly known as the Early Iron Age and Late Iron Age, each of them characterized by distinct pottery styles which first underwent a widespread expansion phase followed by a regionalization phase with many more local pottery styles. Pottery being one of the few material items of cultural heritage that has survived the ravages of time, this is an important step forward for the archeology of Central Africa.”

New insights on the controversial Bantu Expansion

The initial spread of Bantu-speaking people from their homeland on the border between Nigeria and Cameroon towards eastern and southern Africa starting some 4000 years ago is unique in the world due to its magnitude, rapid pace, and adaptation to multiple ecozones. This spread had a momentous impact on the continent’s linguistic, demographic, and cultural landscape. The Bantu languages constitute Africa’s largest language family: about one out of three Africans speak one or several Bantu languages.

Historical linguist and Africanist Koen Bostoen (UGent) is excited about how these new insights that urge us to rethink the Bantu Expansion, one of the most controversial issues in African History: “Africa’s colonization by Bantu speech communities is usually seen as a single, long-term and continuous macro-event. We tend to see today’s Bantu speakers as direct descendants from those who originally settled the rainforest some 2700 years ago. Likewise, we think that current-day Bantu languages developed directly from the ancestral languages of those first settlers. However, our results show that this initial wave of Bantu-speaking Early Iron Age communities had largely vanished from the entire Congo rainforest region by 600 CE. The Bantu languages of this area may thus be almost 1000 years younger than previously thought. Scientifically speaking, this introduces new challenges for our use of linguistic data to reconstruct Africa’s history. More generally, our study shows that African societies faced serious catastrophes long before the transatlantic slave trade and European colonization and had the resilience to overcome them. This is hopeful.”

A prolonged epidemic as the cause of population collapse?

Paleobotanist and tropical forest ecologist Wannes Hubau (UGent & RMCA Tervuren), the other lead author, highlights that the drastic population collapse around 400-600 CE coincided with wetter climatic conditions across the region and may therefore have been promoted by a prolonged disease epidemic: “We note the broad coincidence between the sharp demographic decline in the Congo rainforest and the Justinian Plague (541-750 CE), which is regarded as one of the factors leading to the fall of both the Roman Empire and the Aksumite Empire in Ethiopia. It may have killed up to 100 million people in Asia, Europe, and Africa. We have no firm evidence that the population collapse observed in our archeological data is really due to a persistent vector-borne disease. However, the bacteria Yersinia pestis, which caused the Justinian Plague, has a long-standing presence in Central Africa. One particular strain, still found today in DRC, Zambia, Kenya and Uganda, has prevailed in Central Africa for at least 300 years and is the oldest living strain closely related to the lineage that caused the Black Death in 14th century Europe. We therefore consider a prolonged pandemic of plague to be a plausible hypothesis for the observed supra-regional population decline in 5th-6th century Central Africa.”



More information:
D. Seidensticker el al., “Population collapse in Congo rainforest from 400 CE urges reassessment of the Bantu Expansion,” Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.abd8352

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Hexbyte Glen Cove 'See through soil' could help farmers deal with future droughts thumbnail

Hexbyte Glen Cove ‘See through soil’ could help farmers deal with future droughts

Hexbyte Glen Cove

Princeton researchers used borosilicate glass beads as a substitute for soil to study the behavior of hydrogels acting as water reservoirs in farm fields. The researchers used an additive to correct for distortion from the beads allowing them to clearly observe the hydrogel. Photo by Datta et al/Princeton University Credit: Datta et al/Princeton University

In research that may eventually help crops survive drought, scientists at Princeton University have uncovered a key reason that mixing material called hydrogels with soil has sometimes proven disappointing for farmers.

Hydrogel beads, tiny plastic blobs that can absorb a thousand times their weight in water, seem ideally suited to serve as tiny underground reservoirs of water. In theory, as the dries, hydrogels release water to hydrate plants’ roots, thus alleviating droughts, conserving water, and boosting crop yields.

Yet mixing hydrogels into farmers’ fields has had spotty results. Scientists have struggled to explain these uneven performances in large part because soil—being opaque —has thwarted attempts at observing, analyzing, and ultimately improving hydrogel behaviors.

In a new study, the Princeton researchers demonstrated an experimental platform that allows scientists to study the hydrogels’ hidden workings in soils, along with other compressed, confined environments. The platform relies on two ingredients: a transparent granular medium—namely a packing of glass beads—as a soil stand-in, and water doped with a chemical called ammonium thiocyanate. The chemical cleverly changes the way the water bends light, offsetting the distorting effects the round glass beads would ordinarily have. The upshot is that researchers can see straight through to a colored hydrogel glob amidst the faux soil.

“A specialty of my lab is finding the right chemical in the right concentrations to change the optical properties of fluids,” said Sujit Datta, an assistant professor of chemical and biological engineering at Princeton and senior author of the study appearing in the journal Science Advances on Feb. 12. “This capability enables 3-D visualization of fluid flows and other processes that occur within normally inaccessible, opaque media, such as soil and rocks.”

The scientists used the setup to demonstrate that the amount of water stored by hydrogels is controlled by a balance between the force applied as the hydrogel swells with water and the confining force of the surrounding soil. As a result, softer hydrogels absorb large quantities of water when mixed into surface layers of soil, but don’t work as well in deeper layers of soil, where they experience a larger pressure. Instead, hydrogels that have been synthesized to have more internal crosslinks, and as a result are stiffer and can exert a larger force on the soil as they absorb water, would be more effective in deeper layers. Datta said that, guided by these results, engineers will now be able to conduct further experiments to tailor the chemistry of hydrogels for specific crops and soil conditions.

“Our results provide guidelines for designing hydrogels that can optimally absorb water depending on the soil they are meant to be used in, potentially helping to address growing demands for food and water,” said Datta.

The inspiration for the study came from Datta learning about the immense promise of hydrogels in agriculture but also their failure to meet it in some cases. Seeking to develop a platform to investigate hydrogel behavior in soils, Datta and colleagues started with a faux soil of borosilicate glass beads, commonly used for various bioscience investigations and, in everyday life, costume jewelry. The bead sizes ranged from one to three millimeters in diameter, consistent with the grain sizes of loose, unpacked soil.

When researchers added an aqueous solution of ammonium thiocyanate, it cleared the distortion caused by the borosilicate glass beads and allowed for a clear view of the hydrogel. Video by Datta et al/Princeton University Credit: Datta et al/Princeton University

In summer 2018, Datta assigned Margaret O’Connell, then a Princeton undergraduate student working in his lab through Princeton’s ReMatch+ program, to identify additives that would change water’s refractive index to offset the beads’ light distortion, yet still allow a hydrogel to effectively absorb water. O’Connell alit upon an aqueous solution with a bit over half of its weight contributed by ammonium thiocyanate.

Nancy Lu, a graduate student at Princeton, and Jeremy Cho, then a postdoc in Datta’s lab and now an assistant professor at the University of Nevada, Las Vegas, built a preliminary version of the experimental platform. They placed a colored hydrogel sphere, made from a conventional hydrogel material called polyacrylamide, amidst the beads and gathered some initial observations.

Jean-Francois Louf, a postdoctoral researcher in Datta’s lab, then constructed a second, honed version of the platform and performed the experiments whose results were reported in the study. This final platform included a weighted piston to generate pressure on top of the beads, simulating a range of pressures a hydrogel would encounter in soil, depending upon how deep the is implanted.

Overall, the results showed the interplay between hydrogels and soils, based on their respective properties. A the team developed to capture this behavior will help in explaining the confounding field results gathered by other researchers, where sometimes crop yields improved, but other times hydrogels showed minimal benefits or even degraded the soil’s natural compaction, increasing the risk of erosion.

Ruben Juanes, a professor of civil and environmental engineering at the Massachusetts Institute of Technology who was not involved in the study, offered comments on its significance. “This work opens up tantalizing opportunities for the use of hydrogels as soil capacitors that modulate water availability and control release to crop roots, in a way that could provide a true technological advance in sustainable agriculture,” said Juanes.

Other applications of hydrogels stand to gain from Datta and his colleagues’ work. Example areas include oil recovery, filtration, and the development new kinds of building materials, such as concrete infused with hydrogels to prevent excessive drying out and cracking. One particularly promising area is biomedicine, with applications ranging from drug delivery to wound healing and artificial tissue engineering.

“Hydrogels are a really cool, versatile material that also happen to be fun to work with,” said Datta. “But while most lab studies focus on them in unconfined settings, many applications involve their use in tight and confined spaces. We’re very excited about this simple because it is allowing us to see what other people couldn’t see before.”



More information:
“Under pressure: Hydrogel swelling in a granular medium” Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.abd2711

Citation:
‘See through soil’ could help farmers deal with future droughts (2021, February 12)
retrieved 12 February 2021
from https://phys.org/news/2021-02-soil-farmers-future-droughts.html

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Hexbyte Glen Cove 'Sex, lasers and male competition:' fruit flies win genetic race with rivals thumbnail

Hexbyte Glen Cove ‘Sex, lasers and male competition:’ fruit flies win genetic race with rivals

Hexbyte Glen Cove

UC researchers studied the sex combs of the fruit fly Drosophilia bipectinata. Credit: Michal Polak/UC

Scientists have accepted natural selection as a driver of evolution for more than 160 years, thanks to Charles Darwin.

But University of Cincinnati biologist Michal Polak says Darwin’s book “The Descent of Man” only tells part of the story. Sometimes when the victor vanquishes his sexual rival, the quest to pass genes to the next generation is just beginning.

According to a new UC study published in the journal Current Biology, male flies with the most impressive sexual ornamentation also have super sperm that can outcompete that of rivals in the post-mating fertilization game.

UC studied Drosophila bipectinata, a tiny red-eyed fruit fly from the South Pacific. The male’s forelegs have a distinctive “sex comb,” dark bristles that female fruit flies find appealing—like the colorful train of a male peacock. Scientists previously found that female flies prefer males with more robust sex combs, which the males use to grasp the female’s abdomen before mating.

UC researchers found a strong link between the most impressive sex combs and that male’s competitive success at passing on his genes even after a female fly has mated with other flies. And this competitive edge persisted even after the male’s sex comb was surgically removed with a high-precision laser in UC experiments.

“This is the first robust demonstration of a genetic link between a traditionally Darwinian trait and success in postcopulatory sexual competition,” Polak said. “That’s the surprising link: precopulatory and postcopulatory fitness.”

In his groundbreaking 1859 book “On the Origin of Species,” Darwin framed the idea of by describing how the “fittest” animals pass on their genes to the next generation. This fitness is manifested in having the largest antlers, the most vibrant colors or the vigor to defend a territory.

But Darwin’s theory was incomplete, Polak said, because it failed to recognize that sexual selection continues during and after mating. Female fruit flies are promiscuous, often choosing multiple mates. Fruit flies are hardly alone in that regard, Polak said.

“Promiscuity is much more common across animal species than once was thought,” Polak said.

UC biologist Michal Polak studies the competitive race to pass on genes that takes place after multiple males mate with a female. Credit: Andrew Higley/UC Creative

Scientists living in prim and proper Victorian England did not give enough consideration to the microscopic race to fertilize that begins after mating among multiple successful suitors.

“You have to consider the social context in which Darwin was living,” Polak said.

What females gain from mating with multiple suitors is not always clear, Polak said. But when they do, postcopulatory sexual selection provides a competitive edge.

“It’s evident even in primates. Female chimpanzees and bonobos are promiscuous, so the males have large testes that produce big volumes of sperm,” Polak said.

“And you have species like gorillas where females are not promiscuous. Silverback males enforce monogamy. And lo and be hold, their testes are much smaller relative to body size compared to chimps.”

And if you’re wondering, the relative size of human testes falls somewhere between gorillas and chimps, Polak said.

Polak, a professor of biology in UC’s College of Arts and Sciences, decided to study this species of fruit fly after encountering it while conducting fieldwork in Queensland, Australia.

“I was watching these flies mate on a fruit and looked under the microscope and saw these beautiful sex combs. I thought it would make a good model system to study,” Polak said.

“Sexual selection picks up on these traits and they become really exaggerated,” he said.

UC researchers found a link between a fruit fly’s sexual ornamentation and its success over rivals in fertilizing eggs. Pictured are UC graduate Kassie Hooker, left, and UC biologists Joshua Benoit and Michal Polak. Credit: Andrew Higley/UC Creative

For their study, UC biologists artificially selected males with the largest and smallest sex combs in 11 successive generations of fruit flies to create high and low genetic lines.

Kassie Hooker from 2012 to 2015 worked in Polak’s lab as an undergraduate biology student, undertaking the arduous task of categorizing generations of male fruit flies based on the size of the sex combs on their legs. By counting the teeth in each comb, she separated the males with the largest and smallest sex combs to create distinct genetic lines.

To show that the male fruit fly’s sex comb doesn’t provide any reproductive benefit in mating, researchers used ultraprecise lasers to trim the sex in the high line males to mimic those found in the low line males. But these postsurgical males continued to fertilize more eggs even when females mated with lower-line males first.

The research was supported by the National Science Foundation.

UC assistant professor Joshua Benoit, a study co-author, analyzed the RNA of the flies and identified seminal fluid genes that may be responsible for giving high-line a fertilization advantage.

“There aren’t many studies more interesting than this one,” Benoit said. “Sex, lasers, and male competition, which could describe most 1980s action movies.”

Darwin proposed the theory of sexual selection to account for the evolution of male weaponry and extravagant ornamental displays, Polak said. But UC’s study found a far more complex and interesting battle among the sexes.

“We established a link between Darwinian traits and the postcopulatory arena, which Darwin didn’t recognize was important in evolution at all,” Polak said.



More information:
Michal Polak et al, Positive genetic covariance between male sexual ornamentation and fertilizing capacity, Current Biology (2021). DOI: 10.1016/j.cub.2021.01.046

Citation:
‘Sex, lasers and male competition:’ fruit flies win genetic race with rivals (2021, February 12)
retrieved 12 February 2021
from https://phys.org/news/2021-02-sex-lasers-male-competition-fruit.html

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part may be reproduced without the written permission. The content is provided for information purposes only.

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Hexbyte Glen Cove Vaporised crusts of Earth-like planets found in dying stars thumbnail

Hexbyte Glen Cove Vaporised crusts of Earth-like planets found in dying stars

Hexbyte Glen Cove

Remnants of planetary crust disintegrating under the tidal forces around a cool white dwarf. Material in the disc becomes vapourised close to the central star and flows onto the white dwarf atmosphere. Credit: University of Warwick/Mark Garlick

Remnants of planets with Earth-like crusts have been discovered in the atmospheres of four nearby white dwarf stars by University of Warwick astronomers, offering a glimpse of the planets that may have once orbited them up to billions of years ago.

These crusts are from the outer layers of rocky similar to Earth and Mars and could give astronomers greater insights into the chemistry of the planets that these dying stars once hosted.

The discovery is reported today in the journal Nature Astronomy and includes one of the oldest planetary systems seen by astronomers so far.

The University of Warwick-led team were analyzing data from the European Space Agency’s Gaia telescope of over 1,000 nearby when they came across an unusual signal from one particular white dwarf. The researchers at the University of Warwick received funding from the European Research Council and the Science and Technology Facilities Council (STFC).

They used spectroscopy to analyze the light from the star at different wavelengths, which allows them to detect when elements in the star’s atmosphere are absorbing light at different colors and determine what elements those are and how much is present. They also inspected the 30,000 white dwarf spectra from the Sloan Digital Sky Survey published over the last 20 years.

The signal matched the wavelength of lithium and the astronomers soon discovered three more white dwarfs with the same signal, one of which was also observed with potassium in its atmosphere. By comparing the amount of lithium and potassium with the other elements they detected—sodium and calcium—they found that the ratio of elements matched the chemical composition of the of rocky planets like Earth and Mars, if those crusts and been vaporized and mixed within the gaseous outer layers of the star for 2 million years.

Lead author Dr. Mark Hollands from the University of Warwick’s Department of Physics said: “In the past, we’ve seen all sorts of things like mantle and core material, but we’ve not had a definitive detection of planetary crust. Lithium and potassium are good indicators of crust material, they are not present in high concentrations in the mantle or core.

“Now we know what chemical signature to look for to detect these elements, we have the opportunity to look at a huge number of white dwarfs and find more of these. Then we can look at the distribution of that signature and see how often we detect these planetary crusts and how that compares to our predictions.”

The outer layers of the white dwarfs contain up to 300,000 gigatonnes of rocky debris, which includes up to 60 gigatonnes of lithium and 3,000 gigatonnes of potassium, equivalent to a 60km sphere of similar density to Earth’s crust. The amount of crust material detected is similar in mass to that of the asteroids we see in our own solar system, leading the astronomers to believe that what they are seeing around all four stars is material broken off from a planet, rather than an entire planet itself.

Previous observations of white dwarfs have found evidence of material from the inner core and mantle of planets, but no definitive evidence of crust material. Crust is a small fraction of a planet’s mass and the elements detected in this study are only detectable when the star is very cool. White dwarfs are in the dying phase of their lifecycle, as they have burnt out their fuel and cool over billions of years. These four white dwarfs are thought to have burnt out their fuel up to 10 billion years ago and could be among the oldest white dwarfs formed in our galaxy.

Co-author Dr. Pier-Emmanuel Tremblay from the University of Warwick said: “In one case, we are looking at planet formation around a star that was formed in the Galactic halo, 11-12.5 billion years ago, hence it must be one of the oldest planetary systems known so far. Another of these systems formed around a short-lived star that was initially more than four times the mass of the Sun, a record-breaking discovery delivering important constraints on how fast planets can form around their host stars.”

Among the oldest of these , one is 70% more massive than average and so its huge mass would normally cause any material in its atmosphere to disappear relatively quickly, leading the astronomers to the conclusion that it must be replenishing the crust material from a surrounding debris disk. Furthermore, the astronomers detected more infrared light than expected for the white dwarf alone, which indicates a disk being heated by its star and then re-radiated at longer wavelengths.

Dr. Hollands adds: “As we understand it, rocky planet formation happens in a similar way in different planetary systems. Initially, they are formed from similar material composition to the star, but over time those materials separate and you end up with different chemical compositions in different parts of the planets. We can see that at some point that these objects have undergone differentiation, where the composition is different to the starting composition of the star.

“It is now well understood that most normal like the Sun harbor planets, but now there’s the opportunity to look at the frequency of different types of material as well.”



More information:
Alkali metals in white dwarf atmospheres as tracers of ancient planetary crusts, Nature Astronomy (2021). DOI: 10.1038/s41550-020-01296-7 , https//dx.doi.org/10.1038/s41550-020-01296-7

Citation:
Vaporised crusts of Earth-like planets found in dying stars (2021, February 11)

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Hexbyte Glen Cove Protected areas see continued deforestation but at a reduced rate, research shows thumbnail

Hexbyte Glen Cove Protected areas see continued deforestation but at a reduced rate, research shows

Hexbyte Glen Cove

Amazon deforestation. Credit: Oregon State University

A survey of more than 18,000 land parcels spanning 2 million square miles across 63 countries shows that a “protected area” designation reduces the rate of deforestation but does not prevent it.

Published today in Nature Ecology and Evolution, the findings are important because most live in forests and because the study suggests that just 6.5% of the Earth’s woodlands are truly protected, well below the 2020 target of 17% set by the United Nations’ Convention on Biological Diversity.

The findings are also timely given President Biden’s recent executive order on , which calls for protecting 30% of the United States’ land and waters, up from the current 12%, and developing “a plan for promoting the protection of the Amazon rainforest and other critical ecosystems that serve as global carbon sinks.”

“Evidence indicates that we’re in the middle of a mass extinction event the likes of which the planet has seen only five times before,” said study leader Christopher Wolf, a postdoctoral researcher in the Oregon State University College of Forestry. “Formally have been proposed as a primary tool for reducing deforestation, and therefore stemming species extinctions and slowing reductions in carbon storage.”

In research believed to be the first comprehensive look at how effective protected areas are at limiting loss, Wolf and collaborators used the World Database on Protected Areas and forest change maps to estimate rates of change within protected areas. The rates were then compared to those of control areas with similar characteristics such as elevation, slope and proximity to densely populated areas.

They found protected areas’ deforestation rate is 41% lower than that of unprotected areas. They also found that earlier estimates suggesting 15.7% of the Earth’s forest were protected from deforestation were much too optimistic.

“It’s clearly not enough just to call a forest area ‘protected’ and assume that it really is,” Wolf said. “When you look at conservation effectiveness, you can’t simply rely on the amount of officially protected land as a metric. Nearly one-third of all protected areas are actually under intense human pressure.”

Protected area deforestation rates were highest in Africa, Europe and South America and lowest in Oceania—Australia, New Zealand, Papua New Guinea and nearby island chains.

Among the 63 nations studied, 34 have at least 17% of their forest area protected—i.e., are in line with the target percentage established by the Convention on Biological Diversity.

New Zealand ranked No. 1 in percentage of area protected when effectiveness was factored in, and China ranked last. South Africa’s protected areas were the most effective, with deforestation rates eight times lower than those of control sites. Sierra Leone, Malaysia and Cambodia were the three nations losing their forest cover the fastest.

“Protected area effectiveness is limited by varying levels of monitoring and enforcement and the money available for them,” Wolf said. “Unfortunately, our research shows that protected areas rarely if ever do more than slow down . And in general, the larger the protected area, the higher the rate of .”

That has important implications for the 17% target set by the Convention on Biological Diversity, says co-author Matt Betts, director of the Forest Biodiversity Research Network in OSU’s Department of Forest Ecosystems and Society.

“If you take into account imperfect protected areas’ effectiveness, it could require a near doubling of this original target,” he said.



More information:
A forest loss report card for the world’s protected areas. Nature Ecology and Evolution (2021). DOI: 10.1038/s41559-021-01389-0 , https//dx.doi.org/10.1038/s41559-021-01389-0

Citation:
Protected areas see continued deforestation but at a reduced rate, research shows (2021, February 11)
retrieved 11 February 2021
from https://phys.org/news/2021-02-areas-deforestation.html

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