Resetting the Timeline of Mammal Evolution

A new study, published December 22, 2021 in the journal Nature, has provided the most detailed timeline of mammal evolution to date.

From:  Queen Mary University of London

The research describes a new and fast computational approach to obtain precisely dated evolutionary trees, known as 'timetrees'. The authors used the novel method to analyse a mammal genomic dataset and answer a long-standing question around whether modern placental mammal groups originated before or after the Cretaceous-Palaeogene (K-Pg) mass extinction, which wiped out over 70 per cent of all species, including all dinosaurs.

The findings confirm the ancestors of modern placental mammal groups postdate the K-Pg extinction that occurred 66 million years ago, settling a controversy around the origins of modern mammals. Placental mammals are the most diverse group of living mammals, and include groups such as primates, rodents, cetaceans, carnivorans, chiropterans (bats) as well as humans.

The research team was led by Dr Mario dos Reis (Queen Mary University of London) and Professor Phil Donoghue (University of Bristol), and included scientists from Queen Mary, University of Bristol, UCL, Imperial College London, and the University of Cambridge.

Dr Sandra Álvarez-Carretero, lead author of the paper from UCL (then at Queen Mary), says: "By integrating complete genomes in the analysis and the necessary fossil information, we were able to reduce uncertainties and obtain a precise evolutionary timeline. Did modern mammal groups co-exist with the dinosaurs, or did they originate after the mass extinction? We now have a definite answer."

"The timeline of mammal evolution is perhaps one of the most contentious topics in evolutionary biology. Early studies provided origination estimates for modern placental groups deep in the Cretaceous, in the dinosaur era. The past two decades had seen studies moving back and forth between post- and pre-K-Pg diversification scenarios. Our precise timeline settles the issue." adds Prof Donoghue, co-senior author of the paper.

With worldwide sequencing projects now producing hundreds to thousands of genome sequences, and with imminent plans to sequence more than a million species, evolutionary biologists will soon have a wealth of information at their hands. However, current methods to analyse the vast genomic datasets available and create evolutionary timelines are inefficient and computationally expensive.

"Inferring evolutionary timelines is a fundamental goal of biology. However, state-of-the-art methods rely on using computers to simulate evolutionary timelines and assess the most plausible ones. In our case, this was difficult due to the gigantic dataset analysed, involving genetic data from almost 5,000 mammal species and 72 complete genomes," Dr dos Reis says.

In this study, the researchers developed a new, fast Bayesian approach to analyse large numbers of genome sequences, whilst also accounting for uncertainties within the data. "We solved the computational hurdles by dividing the analysis in sub-steps: first simulating timelines using the 72 genomes and then using the results to guide the simulations on the remaining species. Using genomes reduces uncertainty because it allows rejection of unplausible timelines from the simulations," says Dr dos Reis.

"Our data processing pipeline sourced as much genomic data for as many mammal species as possible. This was challenging because genetic databases contain inaccuracies and we had to develop a strategy to identify poor quality samples or mislabelled data that had to be removed," adds Dr Asif Tamuri, co-lead author of the paper from UCL, who was responsible for assembling the mammal genomic dataset.

Using their novel approach, the team were able to reduce computation time for this complex analysis from decades to months. "If we had tried to analyse this large mammal dataset in a supercomputer without using the Bayesian method we have developed, we would have had to wait decades to infer the mammal timetree. Just imagine how long this analysis could take if we were to use our own PCs," says Dr Álvarez-Carretero. "In addition, we managed to reduce computation time by a factor of 100. This new approach not only allows the analysis of genomic datasets, but also, by being more efficient, substantially reduces the CO2 emissions released due to computing," Dr Álvarez-Carretero continues.

The method developed in the study could be used to tackle other contentious evolutionary timelines that require analysis of large datasets. By integrating the novel Bayesian approach with the forthcoming genomes from the Darwin Tree of Life and Earth BioGenome projects, the idea of estimating a reliable evolutionary timescale for the Tree of Life now seems within reach.

The research was funded by the Biotechnology and Biological Sciences Research Council.

              https://www.sciencedaily.com/releases/2021/12/211222153053.htm

Footnote from the Blog Editor

Birds are dinosaurs that survived the great extinction of 66 million years ago and so was an Argentine dinosaur that survived for a time.  See this link: Found: the dinosaur that survived mass extinction (theconversation.com) 

  

Largest Group of Rogue Planets Yet Uncovered

Over 70 Found Located in Milky Way Galaxy

From:  European Southern Observatory

December 22, 2021 -- Rogue planets are elusive cosmic objects that have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Not many were known until now, but a team of astronomers, using data from several European Southern Observatory (ESO) telescopes and other facilities, have just discovered at least 70 new rogue planets in our galaxy. This is the largest group of rogue planets ever discovered, an important step towards understanding the origins and features of these mysterious galactic nomads.

"We did not know how many to expect and are excited to have found so many," says Núria Miret-Roig, an astronomer at the Laboratoire d'Astrophysique de Bordeaux, France and the University of Vienna, Austria, and the first author of the new study published today in Nature Astronomy.

Rogue planets, lurking far away from any star illuminating them, would normally be impossible to image. However, Miret-Roig and her team took advantage of the fact that, in the few million years after their formation, these planets are still hot enough to glow, making them directly detectable by sensitive cameras on large telescopes. They found at least 70 new rogue planets with masses comparable to Jupiter's in a star-forming region close to our Sun, in the Upper Scorpius and Ophiuchus constellations [1].

To spot so many rogue planets, the team used data spanning about 20 years from a number of telescopes on the ground and in space. "We measured the tiny motions, the colours and luminosities of tens of millions of sources in a large area of the sky," explains Miret-Roig. "These measurements allowed us to securely identify the faintest objects in this region, the rogue planets."

The team used observations from ESO's Very Large Telescope (VLT), the Visible and Infrared Survey Telescope for Astronomy (VISTA), the VLT Survey Telescope (VST) and the MPG/ESO 2.2-metre telescope located in Chile, along with other facilities. "The vast majority of our data come from ESO observatories, which were absolutely critical for this study. Their wide field of view and unique sensitivity were keys to our success," explains Hervé Bouy, an astronomer at the Laboratoire d'Astrophysique de Bordeaux, France, and project leader of the new research. "We used tens of thousands of wide-field images from ESO facilities, corresponding to hundreds of hours of observations, and literally tens of terabytes of data."

The team also used data from the European Space Agency's Gaia satellite, marking a huge success for the collaboration of ground- and space-based telescopes in the exploration and understanding of our Universe.

The study suggests there could be many more of these elusive, starless planets that we have yet to discover. "There could be several billions of these free-floating giant planets roaming freely in the Milky Way without a host star," Bouy explains.

By studying the newly found rogue planets, astronomers may find clues to how these mysterious objects form. Some scientists believe rogue planets can form from the collapse of a gas cloud that is too small to lead to the formation of a star, or that they could have been kicked out from their parent system. But which mechanism is more likely remains unknown.

Further advances in technology will be key to unlocking the mystery of these nomadic planets. The team hopes to continue to study them in greater detail with ESO's forthcoming Extremely Large Telescope (ELT), currently under construction in the Chilean Atacama Desert and due to start observations later this decade. "These objects are extremely faint and little can be done to study them with current facilities," says Bouy. "The ELT will be absolutely crucial to gathering more information about most of the rogue planets we have found."

Note

[1] The exact number of rogue planets found by the team is hard to pin down because the observations don't allow the researchers to measure the masses of the probed objects. Objects with masses higher than about 13 times the mass of Jupiter are most likely not planets, so they cannot be included in the count. However, since the team didn't have values for the mass, they had to rely on studying the planets' brightness to provide an upper limit to the number of rogue planets observed. The brightness is, in turn, related to the age of the planets themselves, as the older the planet, the longer it has been cooling down and reducing in brightness. If the studied region is old, then the brightest objects in the sample are likely above 13 Jupiter masses, and below if the region is on the younger side. Given the uncertainty in the age of the study region, this method gives a rogue planet count of between 70 and 170.

          https://www.sciencedaily.com/releases/2021/12/211222153104.htm

 

Possible End to Annual Flu Shots

New target for universal influenza vaccine

From:  Scripps Research Institute

December 23, 2021 -- A new antibody discovered in the blood of some people vaccinated against or infected with influenza can recognize a broad variety of flu viruses.

Scientists at Scripps Research, University of Chicago and Icahn School of Medicine at Mount Sinai have identified a new Achilles' heel of influenza virus, making progress in the quest for a universal flu vaccine. Antibodies against a long-ignored section of the virus, which the team dubbed the anchor, have the potential to recognize a broad variety of flu strains, even as the virus mutates from year to year, they reported Dec. 23, 2021 in the journal Nature.

"It's always very exciting to discover a new site of vulnerability on a virus because it paves the way for rational vaccine design," says co-senior author Andrew Ward, PhD, professor of Integrative Structural and Computational Biology at Scripps Research. "It also demonstrates that despite all the years and effort of influenza vaccine research there are still new things to discover."

"By identifying sites of vulnerability to antibodies that are shared by large numbers of variant influenza strains we can design vaccines that are less affected by viral mutations," says study co-senior author Patrick Wilson, MD, who was previously at the University of Chicago and recently recruited to Weill Cornell Medicine as a professor of pediatrics and a scientist in the institution's Gale and Ira Drukier Institute for Children's Health. "The anchor antibodies we describe bind to such a site. The antibodies themselves can also be developed as drugs with broad therapeutic applications."

In a typical year, influenza affects more than 20 million people in the United States and leads to more than 20,000 deaths. Vaccines against influenza typically coax the immune system to generate antibodies that recognize the head of hemagglutinin (HA), a protein that extends outward from the surface of the flu virus. The head is the most accessible regions of HA, making it a good target for the immune system; unfortunately, it is also one of the most variable. From year to year, the head of HA often mutates, necessitating new vaccines.

Researchers have designed experimental influenza vaccines to be more universal, spurring the body to create antibodies against the less-variable stalk region of HA, which extends like a stem between the influenza virion and the HA head. Some of these universal flu vaccines are currently in early clinical trials.

In the new study, a collaborative team of scientists characterized 358 different antibodies present in the blood of people who had either been given a seasonal influenza vaccine, were in a phase I trial for an experimental, universal influenza vaccine, or had been naturally infected with influenza.

Many of the antibodies present in the blood of participants were antibodies already known to recognize either the HA head or stalk. But a collection of new antibodies stood out; the antibodies bound to the very bottom of the stalk, near where each HA molecule is attached to the membrane of the flu virion.

The co-first authors of the manuscript -- Julianna Han, a staff scientist in the Ward lab, and Jenna Guthmiller, a postdoctoral fellow at the University of Chicago -- named this section of HA the anchor, and began studying it further. In all, the scientists identified 50 different antibodies to the HA anchor, from a total of 21 individuals. The antibodies, they discovered, recognized a variety of H1 influenza viruses, which account for many seasonal flu strains. Some of the antibodies were also able to recognize pandemic H2 and H5 strains of influenza in lab tests. And in mice, the antibodies successfully protected against infection by three different H1 influenza viruses.

"In order to increase our protection to these highly mutating viruses, we need to have as many tools as we can," says Han. "This discovery adds one more highly potent target to our repertoire." Importantly, these antibodies appear to be fairly common in people, and belong to a class of antibodies that any person's body can produce -- an important consideration in designing a vaccine to spur their development.

"The human immune system already has the ability to make antibodies to this epitope, so it's just a matter of applying modern protein engineering methods to make a vaccine that can induce those antibodies in sufficient numbers," adds Guthmiller.

The researchers say that future, improved iterations of a universal vaccine could more purposefully aim to generate anchor antibodies. Until now, scientists designing universal vaccines hadn't paid attention to whether the anchor region of the stem was included as a target. Ideally, a universal influenza vaccine will lead to antibodies against multiple sections of the virus -- such as both the HA anchor and the stalk -- to increase protection to evolving viruses.

The researchers are planning future studies on how to design a vaccine that most directly targets the HA anchor of different influenza strains.

In addition to Han and Ward, authors of the study, "Broadly neutralizing antibodies target a hemagglutinin anchor epitope," include Sara Richey and Alba Torrents de la Pena of Scripps; Jenna Guthmiller, Henry Utset, Lei Li, Linda Yu-Ling Lan, Carole Henry, Christopher Stamper, Olivia Stovicek, Haley Dugan, Nai-Ying Zheng, Micah Tepora, Dalia Bitar, Siriruk Changrob, Min Huang and Patrick Wilson of University of Chicago; Meagan McMahon, George O'Dell, Alec Freyn, Fatima Amanat, Victoria Rosado, Shirin Strohmeier, Adolfo Garcia-Sastre, Raffael Nachbagauer, Peter Palese and Florian Krammer of Icahn School of Medicine at Mount Sinai; Monica Fernandez-Quintero and Klaus Liedl of University of Innsbruck, Lauren Gentles and Jesse Bloom of Fred Hutchinson Cancer Research Center; and Lynda Coughlan of University of Maryland School of Medicine

              https://www.sciencedaily.com/releases/2021/12/211223113049.htm

 

South African Archbishop Desmond Tutu Died

Desmond Mpilo Tutu OMSG CH GCStJ (7 October 1931– 26 December 2021) was a South African Anglican bishop and theologian, known for his work as an anti-apartheid and human rights activist.  He was Bishop of Johannesburg from 1985 to 1986 and then Archbishop of Cape Town from 1986 to 1996, in both cases being the first black African to hold the position. Theologically, he sought to fuse ideas from black theology with African theology.

Desmond Mpilo Tutu was born of mixed Xhosa and Motswana heritage to a poor family in Klerksdorp, South Africa.  Entering adulthood, he trained as a teacher and married Nomalizo Leah Shenxane in 1955, with whom he had four children, including Mpho Tutu van Furth.  In 1960, he was ordained as an Anglican priest and in 1962, he moved to the United Kingdom to study theology at King's College London.  In 1966 he returned to Africa, teaching at the Federal Theological Seminary in South Africa, and then the University of Botswana, Lesotho and Swaziland. In 1972, he became the Theological Education Fund's director for Africa, a position based in London but necessitating regular tours of the African continent. Back in southern Africa in 1975, he served first as dean of St Mary's Cathedral in Johannesburg and then as Bishop of Lesotho.

From 1978 to 1985 he was general-secretary of the South African Council of Churches.  He emerged as one of the most prominent opponents of South Africa's apartheid system of racial segregation and white minority rule.  Although warning the National Party government that anger at apartheid would lead to racial violence, as an activist he stressed non-violent protest and foreign economic pressure to bring about universal suffrage.

In 1985, Tutu became Bishop of Johannesburg and in 1986 the Archbishop of Cape Town, the most senior position in southern Africa's Anglican hierarchy. In this position, he emphasised a consensus-building model of leadership and oversaw the introduction of female priests.  Also in 1986, he became president of the All Africa Conference of Churches, resulting in further tours of the continent.  After President F. W. de Klerk released the anti-apartheid activist Nelson Mandela from prison in 1990 and the pair led negotiations to end apartheid and introduce multi-racial democracy, Tutu assisted as a mediator between rival black factions. After the 1994 general election resulted in a coalition government headed by Mandela, the latter selected Tutu to chair the Truth and Reconciliation Commission to investigate past human rights abuses committed by both pro and anti-apartheid groups. Following apartheid's fall, Tutu campaigned for gay rights and spoke out on a wide range of subjects, among them his support of Palestinians in the Israeli–Palestinian conflict (alongside his simultaneous belief in Israel's right to exist), his opposition to the Iraq War, and his criticism of South African presidents Thabo Mbeki and Jacob Zuma.  In 2010, he retired from public life.

As Tutu rose to prominence in the 1970s, white conservatives who supported apartheid despised him, while many white liberals regarded him as too radical; many black radicals accused him of being too moderate and focused on cultivating white goodwill, while Marxist–Leninists criticised his anti-communist stance. He was popular among South Africa's black majority and was internationally praised for his work involving anti-apartheid activism, resulting in him receiving a range of awards including the Nobel Peace Prize.  He also compiled several books of his speeches and sermons.

                                https://en.wikipedia.org/wiki/Desmond_Tutu 

Clues to Treatment of Schizophrenia and Bipolar Disorder

Scientists investigating the DNA outside our genes - the 'dark genome' - have discovered recently evolved regions that code for proteins associated with schizophrenia and bipolar disorder.

From:  Cambridge University

December 23, 2021 -- They say these new proteins can be used as biological indicators to distinguish between the two conditions, and to identify patients more prone to psychosis or suicide.

Schizophrenia and bipolar disorder are debilitating mental disorders that are hard to diagnose and treat. Despite being amongst the most heritable mental health disorders, very few clues to their cause have been found in the sections of our DNA known as genes.

The scientists think that hotspots in the 'dark genome' associated with the disorders may have evolved because they have beneficial functions in human development, but their disruption by environmental factors leads to susceptibility to, or development of, schizophrenia or bipolar disorder.

The results are published today in the journal Molecular Psychiatry.

"By scanning through the entire genome we've found regions, not classed as genes in the traditional sense, which create proteins that appear to be associated with schizophrenia and bipolar disorder," said Dr Sudhakaran Prabakaran, who was based in the University of Cambridge's Department of Genetics when he conducted the research, and is senior author of the report.

He added: "This opens up huge potential for new druggable targets. It's really exciting because nobody has ever looked beyond the genes for clues to understanding and treating these conditions before."

The researchers think that these genomic components of schizophrenia and bipolar disorder are specific to humans -- the newly discovered regions are not found in the genomes of other vertebrates. It is likely that the regions evolved quickly in humans as our cognitive abilities developed, but they are easily disrupted -- resulting in the two conditions.

"The traditional definition of a gene is too conservative, and it has diverted scientists away from exploring the function of the rest of the genome," said Chaitanya Erady, a researcher in the University of Cambridge's Department of Genetics and first author of the study.

She added: "When we look outside the regions of DNA classed as genes, we see that the entire human genome has the ability to make proteins, not just the genes. We've found new proteins that are involved in biological processes and are dysfunctional in disorders like schizophrenia and bipolar disorder."

The majority of currently available drugs are designed to target proteins coded by genes. The new finding helps to explain why schizophrenia and bipolar disorder are heritable conditions, and could provide new targets for future treatments.

Schizophrenia is a severe, long-term mental health condition that may result in hallucinations, delusions, and disordered thinking and behaviour, while bipolar disorder causes extreme mood swings ranging from mania to depression. The symptoms sometimes make the two disorders difficult to tell apart.

Prabakaran left his University position earlier this year to create the company NonExomics, in order to commercialise this and other discoveries. Cambridge Enterprise, the commercialisation arm of the University of Cambridge, has assisted NonExomics by licensing the intellectual property. Prabakaran has raised seed funding to develop new therapeutics that will target the proteins implicated in schizophrenia and bipolar disorder, and other diseases.

His team has now discovered 248,000 regions of DNA outside of the regions conventionally defined as genes, which code for new proteins that are disrupted in disease.

           https://www.sciencedaily.com/releases/2021/12/211223225442.htm

  

‘Pop-up’ Electronic Sensors Could Detect When Individual Heart Cells Misbehave

UC San Diego engineers developed a powerful new tool that directly measures the movement and speed of electrical signals inside heart cells, using tiny 'pop-up' sensors that poke into cells without damaging them. It could be used to gain more detailed insights into heart disorders and diseases.

From:  University of California, San Diego

December 23, 2021 -- The device directly measures the movement and speed of electrical signals traveling within a single heart cell -- a first -- as well as between multiple heart cells. It is also the first to measure these signals inside the cells of 3D tissues.

The device, published Dec. 23 in the journal Nature Nanotechnology, could enable scientists to gain more detailed insights into heart disorders and diseases such as arrhythmia (abnormal heart rhythm), heart attack and cardiac fibrosis (stiffening or thickening of heart tissue).

"Studying how an electrical signal propagates between different cells is important to understand the mechanism of cell function and disease," said first author Yue Gu, who recently received his Ph.D. in materials science and engineering at UC San Diego. "Irregularities in this signal can be a sign of arrhythmia, for example. If the signal cannot propagate correctly from one part of the heart to another, then some part of the heart cannot receive the signal so it cannot contract."

"With this device, we can zoom in to the cellular level and get a very high resolution picture of what's going on in the heart; we can see which cells are malfunctioning, which parts are not synchronized with the others, and pinpoint where the signal is weak," said senior author Sheng Xu, a professor of nanoengineering at the UC San Diego Jacobs School of Engineering. "This information could be used to help inform clinicians and enable them to make better diagnoses."

The device consists of a 3D array of microscopic field effect transistors, or FETs, that are shaped like sharp pointed tips. These tiny FETs pierce through cell membranes without damaging them and are sensitive enough to detect electrical signals -- even very weak ones -- directly inside the cells. To evade being seen as a foreign substance and remain inside the cells for long periods of time, the FETs are coated in a phospholipid bilayer. The FETs can monitor signals from multiple cells at the same time. They can even monitor signals at two different sites inside the same cell.

"That's what makes this device unique," said Gu. "It can have two FET sensors penetrate inside one cell -- with minimal invasiveness -- and allow us to see which way a signal propagates and how fast it goes. This detailed information about signal transportation within a single cell has so far been unknown."

To build the device, the team first fabricated the FETs as 2D shapes, and then bonded select spots of these shapes onto a pre-stretched elastomer sheet. The researchers then loosened the elastomer sheet, causing the device to buckle and the FETs to fold into a 3D structure so that they can penetrate inside cells.

"It's like a pop-up book," said Gu. "It starts out as a 2D structure, and with compressive force it pops up at some portions and becomes a 3D structure."

The team tested the device on heart muscle cell cultures and on cardiac tissues that were engineered in the lab. The experiments involved placing either the cell culture or tissue on top of the device and then monitoring the electrical signals that the FET sensors picked up. By seeing which sensors detected a signal first and then measuring the times it took for other sensors to detect the signal, the team could determine which way the signal traveled and its speed. The researchers were able to do this for signals traveling between neighboring cells, and for the first time, for signals traveling within a single heart muscle cell.

What makes this even more exciting, said Xu, is that this is the first time that scientists have been able to measure intracellular signals in 3D tissue constructs. "So far, only extracellular signals, meaning signals that are outside of the cell membrane, have been measured in these types of tissues. Now, we can actually pick up signals inside the cells that are embedded in the 3D tissue or organoid," he said.

The team's experiments led to an interesting observation: signals inside individual heart cells travel almost five times faster than signals between multiple heart cells. Studying these kinds of details could reveal insights on heart abnormalities at the cellular level, said Gu. "Say you're measuring the signal speed in one cell, and the signal speed between two cells. If there's a very big difference between these two speeds -- that is, if the intercellular speed is much, much smaller than the intracellular speed -- then it's likely that something is wrong at the junction between the cells, possibly due to fibrosis," he explained.

Biologists could also use this device to study signal transportation between different organelles in a cell, added Gu. A device like this could also be used for testing new drugs and seeing how they affect heart cells and tissues.

The device would also be useful for studying electrical activity inside neurons. This is a direction that the team is looking to explore next. Down the line, the researchers plan to use their device to record electrical activity in real biological tissue in vivo. Xu envisions an implantable device that can be placed on the surface of a beating heart or on the surface of the cortex. But the device is still far from that stage. To get there, the researchers have more work to do including fine-tuning the layout of the FET sensors, optimizing the FET array size and materials, and integrating AI-assisted signal processing algorithms into the device.

Paper: "Three-dimensional transistor arrays for intra- and inter-cellular recording." Co-authors include Chunfeng Wang, Namheon Kim, Jingxin Zhang, Tsui Min Wang, Jennifer Stowe, Jing Mu, Muyang Lin, Weixin Li, Chonghe Wang, Hua Gong, Yimu Chen, Yusheng Lei, Hongjie Hu, Yang Li, Lin Zhang, Zhenlong Huang, Pooja Banik, Liangfang Zhang and Andrew D. McCulloch, UC San Diego; Rohollah Nasiri, Samad Ahadian and Ali Khademhosseini, Terasaki Institute for Biomedical Innovation; Jinfeng Li and Peter J. Burke, UC Irvine; Leo Huan-Hsuan Hsu, Xiaochuan Dai and Xiaocheng Jiang, Tufts University; Zheyuan Liu, Massachusetts Institute of Technology; and Xingcai Zhang, Harvard University.

This work was supported by the National Institutes of Health (1 R35 GM138250 01).

https://www.sciencedaily.com/releases/2021/12/211223113054.htm

 

James Webb Space Telescope Launched

Telescope launches to see first galaxies and distant worlds

From:  NASA

December 25, 2021 -- NASA’s James Webb Space Telescope launched at 7:20 a.m. EST Saturday on an Ariane 5 rocket from Europe’s Spaceport in French Guiana, South America.

A joint effort with ESA (European Space Agency) and the Canadian Space Agency, the Webb observatory is NASA’s revolutionary flagship mission to seek the light from the first galaxies in the early universe and to explore our own solar system, as well as planets orbiting other stars, called exoplanets. 

“The James Webb Space Telescope represents the ambition that NASA and our partners maintain to propel us forward into the future,” said NASA Administrator Bill Nelson. “The promise of Webb is not what we know we will discover; it’s what we don’t yet understand or can’t yet fathom about our universe. I can’t wait to see what it uncovers!”

Ground teams began receiving telemetry data from Webb about five minutes after launch. The Arianespace Ariane 5 rocket performed as expected, separating from the observatory 27 minutes into the flight. The observatory was released at an altitude of approximately 870 miles (1,400 kilometers). Approximately 30 minutes after launch, Webb unfolded its solar array, and mission managers confirmed that the solar array was providing power to the observatory. After solar array deployment, mission operators will establish a communications link with the observatory via the Malindi ground station in Kenya, and ground control at the Space Telescope Science Institute in Baltimore will send the first commands to the spacecraft.

Engineers and ground controllers will conduct the first of three mid-course correction burns about 12 hours and 30 minutes after launch, firing Webb’s thrusters to maneuver the spacecraft on an optimal trajectory toward its destination in orbit about 1 million miles from Earth.

“I want to congratulate the team on this incredible achievement – Webb’s launch marks a significant moment not only for NASA, but for thousands of people worldwide who dedicated their time and talent to this mission over the years,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “Webb’s scientific promise is now closer than it ever has been. We are poised on the edge of a truly exciting time of discovery, of things we’ve never before seen or imagined.”

The world’s largest and most complex space science observatory will now begin six months of commissioning in space. At the end of commissioning, Webb will deliver its first images. Webb carries four state-of-the-art science instruments with highly sensitive infrared detectors of unprecedented resolution. Webb will study infrared light from celestial objects with much greater clarity than ever before. The premier mission is the scientific successor to NASA’s iconic Hubble and Spitzer space telescopes, built to complement and further the scientific discoveries of these and other missions.

“The launch of the Webb Space Telescope is a pivotal moment – this is just the beginning for the Webb mission,” said Gregory L. Robinson, Webb’s program director at NASA Headquarters. “Now we will watch Webb’s highly anticipated and critical 29 days on the edge. When the spacecraft unfurls in space, Webb will undergo the most difficult and complex deployment sequence ever attempted in space. Once commissioning is complete, we will see awe-inspiring images that will capture our imagination.”

The telescope’s revolutionary technology will explore every phase of cosmic history – from within our solar system to the most distant observable galaxies in the early universe, to everything in between. Webb will reveal new and unexpected discoveries and help humanity understand the origins of the universe and our place in it.

NASA Headquarters oversees the mission for the agency’s Science Mission Directorate. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages Webb for the agency and oversees work on the mission performed by the Space Telescope Science Institute, Northrop Grumman, and other mission partners. In addition to Goddard, several NASA centers contributed to the project, including the agency’s Johnson Space Center in Houston, Jet Propulsion Laboratory in Southern California, Marshall Space Flight Center in Huntsville, Alabama, Ames Research Center in California’s Silicon Valley, and others.

https://www.nasa.gov/press-release/nasas-webb-telescope-launches-to-see-first-galaxies-distant-worlds

 

A Big Push to Lift People Out of Poverty

MIT field experiment from India finds a one-time economic boost helps the very poor fare better for at least a decade.

By Peter Dizikes at MIT News Office

December 22, 2021 -- A field experiment in India led by MIT antipoverty researchers has produced a striking result: A one-time boost of capital improves the condition of the very poor even a decade later.

The experiment, based on a “Targeting the Ultra-Poor” (TUP) program that aids people living in extreme poverty, generated positive effects on consumption, food security, income, and health, which grew fairly steadily for seven years after the start of the program, and then remained intact after 10 years as well.

The study, based in rural West Bengal, India, centered on people so poor their average daily household consumption was the equivalent of $1.35 in 2018 U.S. dollars. By the end of the experiment, people helped by the TUP program had seen their incomes increase by about 30 percent compared to those not in the program.

These findings suggest that many people are mired in a “poverty trap,” unable to improve their circumstances because of their pronounced lack of resources in the first place. But “big push” programs, like the TUP policy used in the experiment, can change that.  

“The usual idea of a poverty trap is that there is an economic opportunity that the poor cannot take advantage of because they are too poor,” says Abhijit Banerjee, an MIT development economist and co-author of a new paper detailing the study’s results. “A program like this makes it possible for them to take advantage of the opportunity and get richer, which allows them to continue to benefit from it.”

Additionally, the India program generated economic benefits that were, at a very conservative estimate, 4.33 times its costs.

“The social benefits seem to be overwhelmingly larger than the costs,” says Banerjee, the Ford International Professor of Economics at MIT.

The paper, “Long-Term Effects of the Targeting the Ultra-Poor Program,” is published in this month’s issue of the American Economic Review: Insights. The authors are Banerjee; Esther Duflo, the Abdul Latif Jameel Professor of Poverty Alleviation and Development Economics at MIT; and Garima Sharma, a doctoral student in MIT’s Department of Economics.

In addition to being professors in MIT’s Department of Economics, Banerjee and Duflo are two of the three co-founders of MIT’s Abdul Latif Jameel Poverty Action Lab (J-PAL), an organization dedicated to antipoverty field experiments around the world. Banerjee and Duflo, along with Harvard University economist Michael Kremer, also shared the 2019 Nobel Prize in economic sciences.

TUP programs were pioneered by BRAC, a large nongovernmental organization located in Bangladesh. The version of it developed for the MIT experiment started in 2007, covering 120 village hamlets in West Bengal. Ultimately 266 participating households were offered a one-time boost of assets; about 82 percent of those households chose livestock. Additionally, the households received 30-40 weeks of consumption support, some access to savings, and weekly consultations with staff from India-based Bandhan Bank for 18 months. The results of this set of households were compared to those of similar households, which were identified at the start of the study but did not opt to participate in the program.

Overall, the consumption levels of participating households grew from the equivalent of $1.35 per day, in 2018 U.S. dollars, to $3.53 per day. Households not participating in the program also saw their consumption rise, but at a lower level, from $1.35 per day to $2.90 per day.

Similarly, households participating in the TUP program saw their incomes rise by greater levels as well: On a per-month basis, earnings were $170 at 18 months of the program, $313 after three years, $617 after seven years, and $680 after 10 years. For equivalent households not participating in the program, earnings were $144 at 18 months of the program, $271 after three years, $412 after seven years, and $497 after 10 years.

An intriguing and important aspect of the study is what it illuminates about how the very poor were able to increase their earnings. As the paper notes, there is a “complex dynamic response” at play over time. At first, households earn more from their increased livestock holdings, although that relative difference shrinks over time. But households in their study were then able to diversify their sources of self-generated income and gain more wage earnings.

“What our results show is that in a dynamic economy the opportunity is not always the same — and therefore it is not enough to get started and then just hold on and get pulled along,” Banerjee says. “Even the very poor need to respond to the changing opportunities to stay ahead, and the program actually prepares them to do so, to pivot more effectively to new things when the old one starts looking shaky. The source of this might in part be enhanced self-confidence.”

The MIT experiment reinforces that TUP programs can clearly work. With TUP programs being implemented in a wide range of countries, an open question is how well they may continue to work, in a variety of settings. Banerjee suggests getting the details right, in terms of how each program functions, may be the most important issue for these “big push” efforts, going forward. 

“How effectively these programs can be implemented, either by government officials or unpaid volunteers from self-help groups or other associations of the poor, is the most important question for scaling,” Banerjee observes. “These implementers play a key role in the program because, at the initial stages, it is critical to encourage the beneficiaries and convince them that they can do it, and it may be that those soft interventions are less well-implemented in government programs.”

The study received financial support from the India-based Bandhan Bank; the Consultative Group to Assist the Poor (CGAP), a Washington-based NGO; and the Ford Foundation. It received additional support from Biotech International, and the Center for Microfinance.

             https://news.mit.edu/2021/tup-people-poverty-decade-1222

  

Wise Old Elephants Keep the Young Calm

From:  The University of Exeter, performing research in Botswana.

The results were published December 22, 2021, and show that groups of male elephants show more aggression when not led by older male elephants.  When young male elephants are in charge and set the standards, aggression against vehicles, other animals, and even humans is more pronounced.  See https://www.exeter.ac.uk/research/news/articles/wiseoldelephantskeeptheyo.html

  

Shark Antibody-like Proteins Neutralize COVID-19 Virus

Small, unique antibody-like proteins known as VNARs -- derived from the immune systems of sharks -- can prevent the virus that causes COVID-19, its variants, and related coronaviruses from infecting human cells, according to a new study.

From: University of Wisconsin, Madison

December 17, 2021 --The new VNARs will not be immediately available as a treatment in people, but they can help prepare for future coronavirus outbreaks. The shark VNARs were able to neutralize WIV1-CoV, a coronavirus that is capable of infecting human cells but currently circulates only in bats, where SARS-CoV-2, the virus that causes COVID-19, likely originated.

Developing treatments for such animal-borne viruses ahead of time can prove useful if those viruses make the jump to people.

"The big issue is there are a number of coronaviruses that are poised for emergence in humans," says Aaron LeBeau, a University of Wisconsin-Madison professor of pathology who helped lead the study. "What we're doing is preparing an arsenal of shark VNAR therapeutics that could be used down the road for future SARS outbreaks. It's a kind of insurance against the future."

LeBeau and his lab in the School of Medicine and Public Health collaborated with researchers at the University of Minnesota and Elasmogen, a biomedical company in Scotland that is developing therapeutic VNARs. The team published its findings in Nature Communications.

The anti-SARS-CoV-2 VNARs were isolated from Elasmogen's large synthetic VNAR libraries. One-tenth the size of human antibodies, the shark VNARs can bind to infectious proteins in unique ways that bolster their ability to halt infection.

"These small antibody-like proteins can get into nooks and crannies that human antibodies cannot access," says LeBeau. "They can form these very unique geometries. This allows them to recognize structures in proteins that our human antibodies cannot."

The researchers tested the shark VNARs against both infectious SARS-CoV-2 and a "pseudotype," a version of the virus that can't replicate in cells. They identified three candidate VNARs from a pool of billions that effectively stopped the virus from infecting human cells. The three shark VNARs were also effective against SARS-CoV-1, which caused the first SARS outbreak in 2003.

One VNAR, named 3B4, attached strongly to a groove on the viral spike protein near where the virus binds to human cells and appears to block this attachment process. This groove is very similar among genetically diverse coronaviruses, which even allows 3B4 to effectively neutralize the MERS virus, a distant cousin of the SARS viruses.

The ability to bind such conserved regions across diverse coronaviruses makes 3B4 an attractive candidate to fight viruses that have yet to infect people.

           https://www.sciencedaily.com/releases/2021/12/211217102915.htm

  

The Iridescent Glow of Certain Bird Feathers

From:  Princeton University

December 21, 2021 -- The iridescent shimmer that makes birds such as peacocks and hummingbirds so striking is rooted in a natural nanostructure so complex that people are only just beginning to replicate it technologically. The secret to how birds produce these brilliant colors lies in a key feature of the feather's nanoscale design, according to a study led by Princeton University researchers and published in the journal eLife.

The researchers found an evolutionary tweak in feather nanostructure that has more than doubled the range of iridescent colors birds can display. This insight could help researchers understand how and when brilliant iridescence first evolved in birds, as well as inspire the engineering of new materials that can capture or manipulate light.

As iridescent birds move, nanoscale structures within their feathers' tiny branch-like filaments -- known as barbules -- interact with light to amplify certain wavelengths depending on the viewing angle. This iridescence is known as structural coloration, wherein crystal-like nanostructures manipulate light.

"If you take a single barbule from an iridescent feather, cross-section it and put it under an electron microscope, you'll see an ordered structure with black dots, or sometimes black rings or platelets, within a gray substrate," said first author Klara Nordén, a Ph.D. student in the lab of senior author Mary Caswell Stoddard, associate professor of ecology and evolutionary biology at Princeton and associated faculty in Princeton's High Meadows Environmental Institute (HMEI). "The black dots are pigment-filled sacs called melanosomes, and the gray surrounding them is feather keratin. I find these nanoscale structures just as beautiful as the colors they produce."

Curiously, the melanosome structures come in variety of shapes. They can be rod-shaped or platelet-shaped, solid or hollow. Hummingbirds, for example, tend to have hollow, platelet-shaped melanosomes, while peacocks have rod-shaped melanosomes. But why birds evolved iridescent nanostructures with so many different types of melanosomes has been a mystery, with scientists unsure if some melanosome types are better than others at producing a broad range of vibrant colors.

To answer this question, the researchers combined evolutionary analysis, optical modeling and plumage measurements -- all of which allowed them to uncover general design principles behind iridescent feather nanostructures.

Nordén and Stoddard worked with co-author Chad Eliason, a postdoctoral fellow at The Field Museum, to first survey the literature and compile a database of all described iridescent feather nanostructures in birds, which included more than 300 species. They then used a family tree of birds to illustrate which groups evolved the different melanosome types.

There are five primary types of melanosomes in iridescent feather nanostructures: thick rods, thin rods, hollow rods, platelets and hollow platelets. Except for thick rods, all of these melanosome types are found in brilliantly colored plumage. Because the ancestral melanosome type is rod-shaped, previous work focused on the two obvious features unique to iridescent structures: platelet shape and hollow interior.

However, when the researchers evaluated the results of their survey, they realized that there was a third melanosome feature that has been overlooked -- thin melanin layers. All four melanosome types in iridescent feathers -- thin rods, hollow rods, platelets and hollow platelets -- create thin melanin layers, much thinner than a structure built with thick rods. This is important because the size of the layers in the structures is key to producing vibrant colors, Nordén said.

"Theory predicts that there is a kind of Goldilocks zone in which the melanin layers are just the right thickness to produce really intense colors in the bird-visible spectrum," she said. "We suspected that thin rods, platelets or hollow forms may be alternative ways to reach that ideal thickness from the much larger ancestral melanosome size -- the thick rods."

The researchers tested their idea on bird specimens at the American Museum of Natural History in New York City by measuring the color of iridescent bird plumage that results from nanostructures with different melanosome types. They also used optical modeling to simulate the colors that would be possible to produce with different types of melanosomes. From these data, they determined which feature -- thin melanin layers, platelet shape or hollowness -- has the greatest influence on the range and intensity of color. Combining the results of the optical modeling and plumage analyses, the researchers determined that thin melanin layers -- no matter the shape of the melanosomes -- nearly doubled the range of colors an iridescent feather could produce.

"This key evolutionary breakthrough -- that melanosomes could be arranged in thin melanin layers -- unlocked new color-producing possibilities for birds," Stoddard said. "The diverse melanosome types are like a flexible nanostructural toolkit, offering different routes to the same end: brilliant iridescent colors produced by thin melanin layers."

This may explain why there exists such a great diversity of melanosome types in iridescent nanostructures. Iridescent nanostructures likely evolved many times in different groups of birds, but, by chance, thin melanin layers evolved from a thick rod in different ways. Some groups evolved thin melanin layers by flattening the melanosomes (producing platelets), others by hollowing out the interior of the melanosome (producing hollow forms), and yet others by shrinking the size of the rod (producing thin rods).

The findings of the study could be used to reconstruct brilliant iridescence in prehistoric animals, Nordén said. Melanosomes can be preserved in fossil feathers for millions of years, which means that paleontologists can infer original feather color -- even iridescence -- in birds and dinosaurs by measuring the size of fossilized melanosomes.

"Based on the thick solid rods that have been described in the plumage of Microraptor, for example, we can say that this feathered theropod likely had iridescent plumage much more like that of a starling than that of a peacock," Nordén said.

The composition of melanosomes and keratin in bird feathers could hold clues for engineering advanced iridescent nanostructures that can efficiently capture or manipulate light, or be used to produce eco-friendly paints that do not require dyes or pigments. Super-black coatings such as Vantablack similarly use nanostructures that absorb and disperse rather than reflect light, similar to the black plumage of species in the birds-of-paradise (Paradisaeidae) family.

Iridescent feathers also could lead to a richer understanding of multifunctional materials, Nordén said. Unlike human-made materials, which are often developed for a single function, natural materials are inherently multipurpose. Melanin not only helps produce iridescence; it also protects birds from dangerous ultraviolet radiation, strengthens feathers and inhibits microbial growth.

"What if the different types of melanosomes initially evolved for some reason unrelated to the iridescent color -- such as for making the feather mechanically stronger, or more resistant to microbial attack," Nordén said. "These are some of the questions we are excited to tackle next."

            https://www.sciencedaily.com/releases/2021/12/211221133545.htm

 

Abundant Life Beneath Antarctic Ice Shelf

Far beneath the ice shelves of the Antarctic, there is more marine life than expected.

From:  British Antarctic Survey

December 20, 2021 -- A recent study in the journal Current Biology was published this week (20 December 2021).  Despite occupying nearly 1.6 million km², ice shelves are amongst the least known environments on Earth. Life has been seen in these perpetual dark, cold and still habitats on camera but has rarely been collected.

Using hot water, a team of researchers from the Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research, Germany, drilled two holes, through nearly 200 metres of the Ekström Ice Shelf near Neumayer Station III in the South Eastern Weddell Sea in 2018. The environment is harsh and extremely cold (minus 2.2 degrees centigrade).

The fragments of life on the seabed collected were extraordinary and completely unexpected. Despite being several kilometres from the open sea, the biodiversity of the specimens they collected was extremely rich. In fact, richer than many open water samples found on the continental shelf where there are light and food sources.

The team discovered an incredible 77 species - including sabre shaped bryozoans (moss animals) such as Melicerita obliqua and serpulid worms such as Paralaeospira sicula , more than previously known about from this entire environment.

Lead author Dr David Barnes, a marine biologist at British Antarctic Survey, says:

"This discovery of so much life living in these extreme conditions is a complete surprise and reminds us how Antarctic marine life is so unique and special. It's amazing that we found evidence of so many animal types, most feed on micro-algae (phytoplankton) yet no plants or algae can live in this environment. So the big question is how do these animals survive and flourish here?" The team concludes there must be enough algae carried under the ice shelf from open water to fuel a strong food web. Microscopy of samples showed that, surprisingly, annual growth of four of the species was comparable with similar animals in open marine Antarctic shelf habitats.

Co-author Dr Gerhard Kuhn (AWI), who coordinated the drilling project, says:

"Another surprise was to find out how long life has existed here. Carbon dating of dead fragments of these seafloor animals varied from current to 5800 years. So, despite living 3-9 km from the nearest open water, an oasis of life may have existed continuously for nearly 6000 years under the ice shelf. Only samples from the sea floor beneath the floating ice shelf will tell us stories from its past history."

Current theories on what life could survive under ice shelves suggest that all life becomes less abundant as you move further away from open water and sunlight. Past studies have found some small mobile scavengers and predators, such as fish, worms, jellyfish or krill, in these habitats. But filter feeding organisms -- which depend on a supply of food from above -- were expected to be amongst the first to disappear further under the ice.

The team also notes that with climate change and the collapse of these ice shelves, time is running out to study and protect these ecosystems.

https://www.sciencedaily.com/releases/2021/12/211220120032.htm

  

Does Your Resting Heart Rate Determine How Long You’re Going to Live?

The mythic metric has long been associated with performance and longevity. Here's what you need to know.

Tanner Garrity wrote an article in Inside Hook on December 17, 2021, about the legendary importance of the resting heart rate (RHR), focusing on athletes and cardiovascular workouts.  The relationship between resting heart rate and longevity is fairly complex.  See this link:

https://www.insidehook.com/article/health-and-fitness/resting-heart-rate-longevity

 

Advent in Western Christian Practice

Advent is a season of the liturgical year observed in most Christian denominations as a time of expectant waiting and preparation for both the celebration of the Nativity of Christ at Christmas and the return of Christ at the Second Coming.  Advent is the beginning of the liturgical year in Western Christianity, and is part of the wider Christmas and holiday season.

The term "Advent" is also used in Eastern Orthodoxy for the 40-day Nativity Fast, which has practices different from those in the West.  

The name was adopted from Latin adventus "coming; arrival", translating Greek parousia. In the  New Testament, this is the term used for the Second Coming of Christ.  Thus, the season of Advent in the Christian calendar anticipates the "coming of Christ" from three different perspectives: the physical nativity in Bethlehem, the reception of Christ in the heart of the believer, and the eschatological Second Coming.

Practices associated with Advent include keeping an Advent calendar, lighting an Advent wreath, praying an Advent daily devotional, erecting a Christmas tree or a Chrismon tree, lighting a Christingle, as well as other ways of preparing for Christmas, such as setting up Christmas decorations, a custom that is sometimes done liturgically through a hanging of the greens ceremony.  The equivalent of Advent in Eastern Christianity is called the Nativity Fast, but it differs in length and observances, and does not begin the liturgical church year as it does in the West. The Eastern Nativity Fast does not use the equivalent parousia in its preparatory services.

https://en.wikipedia.org/wiki/Advent

 

Language Extinction Triggers Loss of Unique Medicinal Knowledge

From:  University of Zurich

June 9. 2021 -- Language is one of our species' most important skills, as it has enabled us to occupy nearly every corner of the planet. Among other things, language allows indigenous societies to use the biodiversity that surrounds them as a "living pharmacy" and to describe the medicinal properties of plants. Linguists estimate that there are nearly 7,400 languages in the world today.

Most of these languages, however, are not recorded in writing, and many languages are not being passed on to the next generation. This has led linguists to estimate that 30 percent of all languages will disappear by the end of the 21st century. For indigenous cultures who mostly transmit knowledge orally, this high risk of language extinction also threatens their knowledge of medicinal plants.

Threatened languages support most of unique knowledge

Researchers from the University of Zurich have now assessed the degree to which indigenous knowledge of medicinal plants is linked to individual languages. Senior researcher Rodrigo Cámara-Leret and Jordi Bascompte, professor of ecology, analyzed 3,597 medicinal species and 12,495 medicinal applications associated with 236 indigenous languages in North America, northwest Amazonia and New Guinea. "We found that more than 75 percent of all medicinal plant services are linguistically-unique and therefore only known to one language," Cámara-Leret points out.

To quantify how much of this linguistically-unique knowledge may vanish as languages or plants go extinct, the researchers turned to the Glottolog catalog of the world's languages and the IUCN Red List of Threatened Species to gain information on the threat to languages and medicinal plant species, respectively. They found that threatened languages support over 86 percent of all unique knowledge in North America and Amazonia, and 31 percent of all unique knowledge in New Guinea. By contrast, less than 5 percent of medicinal plant species were threatened.

International Decade of Indigenous Languages

The findings of this study indicate that each indigenous language provides unique insights into the medicinal applications associated with biodiversity. Unfortunately, the study suggests that language loss will be even more critical to the extinction of medicinal knowledge than biodiversity loss. The study coincides with the United Nations proclaiming the next 10 years as the International Decade of Indigenous Languages to raise global awareness of the critical situation of many indigenous languages. "The next steps, in line with the vision of the UN, will require mobilizing resources for the preservation, revitalization and promotion of these threatened languages," Bascompte says. Additionally, launching large-scale community-based participatory efforts will be crucial to document endangered medicinal knowledge before it vanishes.

https://phys.org/news/2021-06-language-extinction-triggers-loss-unique.html

Surprising Cause of the Little Ice Age

Cold era, lasting from early 15th to mid-19th centuries, triggered by unusually warm conditions

From:  University of Massachusetts, Amherst

December 15, 2021 -- New research from the University of Massachusetts Amherst provides a novel answer to one of the persistent questions in historical climatology, environmental history and the earth sciences: what caused the Little Ice Age? The answer, we now know, is a paradox: warming.

The Little Ice Age was one of the coldest periods of the past 10,000 years, a period of cooling that was particularly pronounced in the North Atlantic region. This cold spell, whose precise timeline scholars debate, but which seems to have set in around 600 years ago, was responsible for crop failures, famines and pandemics throughout Europe, resulting in misery and death for millions. To date, the mechanisms that led to this harsh climate state have remained inconclusive. However, a new paper published recently in Science Advances gives an up-to-date picture of the events that brought about the Little Ice Age. Surprisingly, the cooling appears to have been triggered by an unusually warm episode.

When lead author Francois Lapointe, postdoctoral researcher and lecturer in geosciences at UMass Amherst and Raymond Bradley, distinguished professor in geosciences at UMass Amherst began carefully examining their 3,000-year reconstruction of North Atlantic sea surface temperatures, results of which were published in the Proceedings of the National Academy of Sciences in 2020, they noticed something surprising: a sudden change from very warm conditions in the late 1300s to unprecedented cold conditions in the early 1400s, only 20 years later.

Using many detailed marine records, Lapointe and Bradley discovered that there was an abnormally strong northward transfer of warm water in the late 1300s which peaked around 1380. As a result, the waters south of Greenland and the Nordic Seas became much warmer than usual. “No one has recognized this before,” notes Lapointe.

Normally, there is always a transfer of warm water from the tropics to the arctic. It’s a well-known process called the Atlantic Meridional Overturning Circulation (AMOC), which is like a planetary conveyor belt. Typically, warm water from the tropics flows north along the coast of Northern Europe, and when it reaches higher latitudes and meets colder arctic waters, it loses heat and becomes denser, causing the water to sink at the bottom of the ocean. This deep-water formation then flows south along the coast of North America and continues on to circulate around the world.

But in the late 1300s, AMOC strengthened significantly, which meant that far more warm water than usual was moving north, which in turn cause rapid arctic ice loss. Over the course of a few decades in the late 1300s and 1400s, vast amounts of ice were flushed out into the North Atlantic, which not only cooled the North Atlantic waters, but also diluted their saltiness, ultimately causing AMOC to collapse. It is this collapse that then triggered a substantial cooling.

Fast-forward to our own time: between the 1960s and 1980s, we have also seen a rapid strengthening of AMOC, which has been linked with persistently high pressure in the atmosphere over Greenland. Lapointe and Bradley think the same atmospheric situation occurred just prior to the Little Ice Age—but what could have set off that persistent high-pressure event in the 1380s?

The answer, Lapointe discovered, is to be found in trees. Once the researchers compared their findings to a new record of solar activity revealed by radiocarbon isotopes preserved in tree rings, they discovered that unusually high solar activity was recorded in the late 1300s. Such solar activity tends to lead to high atmospheric pressure over Greenland.

At the same time, fewer volcanic eruptions were happening on earth, which means that there was less ash in the air. A “cleaner” atmosphere meant that the planet was more responsive to changes in solar output. “Hence the effect of high solar activity on the atmospheric circulation in the North-Atlantic was particularly strong,” said Lapointe.

Lapointe and Bradley have been wondering whether such an abrupt cooling event could happen again in our age of global climate change. They note that there is now much less arctic sea ice due to global warming, so an event like that in the early 1400s, involving sea ice transport, is unlikely. “However, we do have to keep an eye on the build-up of freshwater in the Beaufort Sea (north of Alaska) which has increased by 40% in the past two decades. Its export to the subpolar North Atlantic could have a strong impact on oceanic circulation”, said Lapointe. “Also, persistent periods of high pressure over Greenland in summer have been much more frequent over the past decade and are linked with record-breaking ice melt. Climate models do not capture these events reliably and so we may be underestimating future ice loss from the ice sheet, with more freshwater entering the North Atlantic, potentially leading to a weakening or collapse of the AMOC.”  The authors conclude that there is an urgent need to address these uncertainties.

This research was supported by funding from the National Science Foundation.

https://www.umass.edu/news/article/winter-coming-researchers-uncover-surprising-cause-little-ice-age