SYSTEMIC RACISM

Racial/ethnic minorities comprise small portion of patients referred with AL amyloidosis

Need for more awareness of disease and access to treatments to reach marginalized communities

BOSTON UNIVERSITY SCHOOL OF MEDICINE

Research News

 

(Boston)--Despite being theoretically at an increased risk for AL amyloidosis, underrepresented minorities make up only a small percentage of patients seen at specialized treatment centers for this disease.

AL amyloidosis is caused when a person's antibody-producing white blood cells (i.e. plasma cells) do not function properly and generate abnormal protein fibers made of components of antibodies called light chains, which then deposit in various organs of the body. This severe illness is closely related to, and occasionally overlaps with, multiple myeloma--a cancer of plasma cells. Multiple myeloma is known to be most common hematologic cancer among Black Americans with an incidence rate that is more than two times higher than that observed among White Americans.

To better understand how AL amyloidosis may affect various groups of patients differently, researchers from Boston University School of Medicine (BUSM) examined disease characteristics, treatments, and outcomes according to the self-reported race/ethnicity of patients referred to the Amyloidosis Center from 1990-2020. Among over 2,400 patients with AL amyloidosis seen during this 30-year period, only 14 percent were underrepresented minorities--considerably lower than in the general population. "Systematic underdetection among minorities, along with access barriers to referral centers, may be at the root of this discrepancy," says lead author Andrew Staron, MD, a hematology/oncology fellow at Boston Medical Center.

Despite similarities in disease manifestation, the researchers observed younger age and more severe illness among racial/ethnic minorities. Proportionately, fewer minority patients underwent aggressive treatment with stem cell transplantation as compared to non-Hispanic White patients. The researchers learned that this treatment difference was largely explained by lower educational level and more advanced heart disease among minorities, rather than race/ethnicity itself.

"These findings indicate that, in order to mitigate disparities, earlier disease detection and efforts to reduce economic and/or language barriers are key. After controlling for disease severity and treatment, race/ethnicity did not independently impact survival," explained corresponding senior author Vaishali Sanchorawala, MD, professor of medicine and director of the Amyloidosis Center at BUSM and Boston Medical Center.

According to the researchers, diagnosing AL amyloidosis can be perplexing and requires awareness by healthcare providers to pursue tissue biopsy. Its manifestations such as structural heart changes, nephrosis (kidney disease), and neuropathy (disease of the peripheral nerves) can mimic common disorders like hypertension and diabetes mellitus. "Because these conditions are more prevalent among certain racial/ethnic minority groups, there is an even greater need for awareness of AL amyloidosis in marginalized communities so that the diagnosis is not missed or delayed," adds Sanchorawala.

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These findings appear in Blood Cancer Journal.

PRIVATIZED HEALTH CARE

Under-insured transgender Americans turn to riskier sources for gender-affirming hormones

Insurance coverage and use of hormones among transgender respondents to a national survey

AMERICAN ACADEMY OF FAMILY PHYSICIANS

Research News

 

Under-Insured Transgender Americans Turn to Riskier, Non-Licensed Sources for Gender-Affirming Hormones

Transgender people who lack access to insurance coverage for gender-affirming hormone therapy are more likely to use hormones from sources other than a licensed prescriber, compared to those with insurance coverage. Analysis of the most recent United States Transgender Survey shows that about 9 percent of transgender adults - which comes to about 170,000 transgender adults in the U.S. today - access hormones from non-licensed sources like friends or online. The study found an association between the use of non-prescribed hormones and lack of health insurance or denial of insurance coverage for gender-affirming medical care. Survey respondents also identified insurance coverage as a prevailing barrier; it was ranked as a top issue affecting transgender people in the United States, ranked second only to direct violence.

The authors note that hormones accessed from an unlicensed source may pose health and safety risks, as medications may be unmonitored for content, quality, formulation and dosing. Additionally, use of non-prescription hormones likely entails decreased monitoring of hormone levels and less opportunity for mitigating risks or other forms of harm reduction and preventive care.

Insurance Coverage and Use of Hormones Among Transgender Respondents to a National Survey
Daphna Stroumsa, MD, MPH, et al
University of Michigan, Ann Arbor, Michigan
https://www.annfammed.org/content/18/6/528

CAPTION

When wildfires break out on hot, windy days, they pose a serious threat to people and the environment. This week on Reactions, learn how firefighters are using fertilizer to keep dangerous blazes at bay: https://youtu.be/fNGq8hEuNb8.

CREDIT

The American Chemical Society

Study: crop diversification can improve environmental outcomes without sacrificing yields

IOWA STATE UNIVERSITY

Research News

 

IMAGE: RED CLOVER IS GROWN IN ROTATION WITH CORN AND SOYBEAN. THE CLOVER COMPETES WITH WEEDS GROWING IN OAT STUBBLE AND ADDS NITROGEN FOR THE SUCCEEDING CORN CROP. SUCH CROP DIVERSIFICATION... view more 

CREDIT: PAULA R. WESTERMAN

AMES, Iowa - A new study shows diversifying agricultural systems beyond a narrow selection of crops leads to a range of ecosystem improvements while also maintaining or improving yields. But a professor of agronomy at Iowa State University who co-authored the study said some marketing and agricultural policy considerations will have to change for farmers to adopt diversification practices more widely.

The study, published last week in the academic journal Science Advances, analyzed the results of 5,188 separate studies that included 41,946 comparisons between diversified and simplified agricultural practices. An international team of researchers carried out the study, known as a meta-analysis, and looked for patterns in the mountains of data collected in previous field studies. The results showed that in 63% of the cases examined, diversification enhanced ecosystem services while also maintaining or even improving crop yields. The researchers described this as a "win-win" result.

"The overall conclusion is there's a lot to be gained from diversifying cropping practices," said Matt Liebman, a professor of agronomy at Iowa State and co-author. "Across many different countries in many different climates and soils, with many different crops, the general pattern is that with diversification, you maintain or increase crop yields while gaining environmental benefits."

Agriculture in the Midwest is dominated by just a few crops, mainly corn and soybeans. But the study looked at a range of farming practices aimed at introducing more diversity to cropland. Those diversification practices include crop rotations, planting prairie strips within and along fields, establishing wildlife habitat near fields, reducing tillage and enriching soil with organic matter. Such measures improve water quality, pollination, pest regulation by natural enemies, nutrient turnover and reduced negative climate impacts by sequestering carbon in the soil.

"My colleagues and I wanted to test if diversification is beneficial for both agricultural production and ecosystem services. The current trend is that we simplify major cropping systems worldwide. We grow monocultures on enlarged fields in homogenized landscapes. The results of our study indicate that diversification can reverse the negative impacts that we observe in simplified forms of cropping on the environment and on production itself," said lead author Giovanni Tamburini at the Swedish University of Agricultural Sciences and University of Bari.

Changes in policy needed

Liebman said barriers related to government ag policy, market considerations and the dissemination of data discourage farmers from adopting many of the diversification practices examined in the study. But showing that such practices do not depress yields, and in some cases increase them, might encourage farmers to consider the practices.

Many current policies and market conditions incentivize farmers to focus on a few highly productive and profitable crops. In Iowa, that means corn and soybeans are grown on the majority of cropland. But Liebman said rethinking those considerations, as well as working with farmers to transfer knowledge that allows them to gain confidence with diversification, could lead to wider use of the practices.

The meta-analysis approach allowed the research team to combine data from thousands of other studies that tested how crop diversification affects yields. The researchers used innovative data analytics to find patterns in those results, Liebman said. The approach allowed the research team to gain a new level of insight that isn't possible with individual experiments.

"What our study suggests is that if we want improved water quality and enhanced wildlife habitat and if we want to continue to work on the soil erosion problem, diversification offers a lot of options to us," Liebman said.

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Radioactive elements may be crucial to the habitability of rocky planets

Earth-size planets can have varying amounts of radioactive elements, which generate internal heat that drives a planet's geological activity and magnetism

UNIVERSITY OF CALIFORNIA - SANTA CRUZ

Research News

 

IMAGE: THESE ILLUSTRATIONS SHOW THREE VERSIONS OF A ROCKY PLANET WITH DIFFERENT AMOUNTS OF INTERNAL HEATING FROM RADIOACTIVE ELEMENTS. THE MIDDLE PLANET IS EARTH-LIKE, WITH PLATE TECTONICS AND AN INTERNAL DYNAMO... view more 

CREDIT: ILLUSTRATIONS BY MELISSA WEISS

The amount of long-lived radioactive elements incorporated into a rocky planet as it forms may be a crucial factor in determining its future habitability, according to a new study by an interdisciplinary team of scientists at UC Santa Cruz.

That's because internal heating from the radioactive decay of the heavy elements thorium and uranium drives plate tectonics and may be necessary for the planet to generate a magnetic field. Earth's magnetic field protects the planet from solar winds and cosmic rays.

Convection in Earth's molten metallic core creates an internal dynamo (the "geodynamo") that generates the planet's magnetic field. Earth's supply of radioactive elements provides more than enough internal heating to generate a persistent geodynamo, according to Francis Nimmo, professor of Earth and planetary sciences at UC Santa Cruz and first author of a paper on the new findings, published November 10 in Astrophysical Journal Letters.

"What we realized was that different planets accumulate different amounts of these radioactive elements that ultimately power geological activity and the magnetic field," Nimmo explained. "So we took a model of the Earth and dialed the amount of internal radiogenic heat production up and down to see what happens."

What they found is that if the radiogenic heating is more than the Earth's, the planet can't permanently sustain a dynamo, as Earth has done. That happens because most of the thorium and uranium end up in the mantle, and too much heat in the mantle acts as an insulator, preventing the molten core from losing heat fast enough to generate the convective motions that produce the magnetic field.

With more radiogenic internal heating, the planet also has much more volcanic activity, which could produce frequent mass extinction events. On the other hand, too little radioactive heat results in no volcanism and a geologically "dead" planet.

"Just by changing this one variable, you sweep through these different scenarios, from geologically dead to Earth-like to extremely volcanic without a dynamo," Nimmo said, adding that these findings warrant more detailed studies.

"Now that we see the important implications of varying the amount of radiogenic heating, the simplified model that we used should be checked by more detailed calculations," he said.

A planetary dynamo has been tied to habitability in several ways, according to Natalie Batalha, a professor of astronomy and astrophysics whose Astrobiology Initiative at UC Santa Cruz sparked the interdisciplinary collaboration that led to this paper.

"It has long been speculated that internal heating drives plate tectonics, which creates carbon cycling and geological activity like volcanism, which produces an atmosphere," Batalha explained. "And the ability to retain an atmosphere is related to the magnetic field, which is also driven by internal heating."

Coauthor Joel Primack, a professor emeritus of physics, explained that stellar winds, which are fast-moving flows of material ejected from stars, can steadily erode a planet's atmosphere if it has no magnetic field.

"The lack of a magnetic field is apparently part of the reason, along with its lower gravity, why Mars has a very thin atmosphere," he said. "It used to have a thicker atmosphere, and for a while it had surface water. Without the protection of a magnetic field, much more radiation gets through and the surface of the planet also becomes less habitable."

Primack noted that the heavy elements crucial to radiogenic heating are created during mergers of neutron stars, which are extremely rare events. The creation of these so-called r-process elements during neutron-star mergers has been a focus of research by coauthor Enrico Ramirez-Ruiz, professor of astronomy and astrophysics.

"We would expect considerable variability in the amounts of these elements incorporated into stars and planets, because it depends on how close the matter that formed them was to where these rare events occurred in the galaxy," Primack said.

Astronomers can use spectroscopy to measure the abundance of different elements in stars, and the compositions of planets are expected to be similar to those of the stars they orbit. The rare earth element europium, which is readily observed in stellar spectra, is created by the same process that makes the two longest-lived radioactive elements, thorium and uranium, so europium can be used as a tracer to study the variability of those elements in our galaxy's stars and planets.

Astronomers have obtained europium measurements for many stars in our galactic neighborhood. Nimmo was able use those measurements to establish a natural range of inputs to his models of radiogenic heating. The sun's composition is in the middle of that range. According to Primack, many stars have half as much europium compared to magnesium as the sun, and many stars have up to two times more than the sun.

The importance and variability of radiogenic heating opens up many new questions for astrobiologists, Batalha said.

"It's a complex story, because both extremes have implications for habitability. You need enough radiogenic heating to sustain plate tectonics but not so much that you shut down the magnetic dynamo," she said. "Ultimately, we're looking for the most likely abodes of life. The abundance of uranium and thorium appear to be key factors, possibly even another dimension for defining a Goldilocks planet."

Using europium measurements of their stars to identify planetary systems with different amounts of radiogenic elements, astronomers can start looking for differences between the planets in those systems, Nimmo said, especially once the James Webb Space Telescope is deployed. "The James Webb Space Telescope will be a powerful tool for the characterization of exoplanet atmospheres," he said.

###

In addition to Nimmo, Primack, and Ramirez-Ruiz, the coauthors of the paper include Sandra Faber, professor emerita of astronomy and astrophysics, and postdoctoral scholar Mohammadtaher Safarzadeh.

Researchers model source of eruption on Jupiter's moon Europa

STANFORD UNIVERSITY

Research News

 

IMAGE: THIS ARTIST'S CONCEPTION OF JUPITER'S ICY MOON EUROPA SHOWS A HYPOTHESIZED CRYOVOLCANIC ERUPTION, IN WHICH BRINY WATER FROM WITHIN THE ICY SHELL BLASTS INTO SPACE. A NEW MODEL OF THIS... view more 

CREDIT: IMAGE CREDIT: JUSTICE BLAINE WAINWRIGHT

On Jupiter's icy moon Europa, powerful eruptions may spew into space, raising questions among hopeful astrobiologists on Earth: What would blast out from miles-high plumes? Could they contain signs of extraterrestrial life? And where in Europa would they originate? A new explanation now points to a source closer to the frozen surface than might be expected.

Rather than originating from deep within Europa's oceans, some eruptions may originate from water pockets embedded in the icy shell itself, according to new evidence from researchers at Stanford University, the University of Arizona, the University of Texas and NASA's Jet Propulsion Laboratory.

Using images collected by the NASA spacecraft Galileo, the researchers developed a model to explain how a combination of freezing and pressurization could lead to a cryovolcanic eruption, or a burst of water. The results, published Nov. 10 in Geophysical Research Letters, have implications for the habitability of Europa's underlying ocean - and may explain eruptions on other icy bodies in the solar system.

Harbingers of life?

Scientists have speculated that the vast ocean hidden beneath Europa's icy crust could contain elements necessary to support life. But short of sending a submersible to the moon to explore, it's difficult to know for sure. That's one reason Europa's plumes have garnered so much interest: If the eruptions are coming from the subsurface ocean, the elements could be more easily detected by a spacecraft like the one planned for NASA's upcoming Europa Clipper mission.

But if the plumes originate in the moon's icy shell, they may be less hospitable to life, because it is more difficult to sustain the chemical energy to power life there. In this case, the chances of detecting habitability from space are diminished.

"Understanding where these water plumes are coming from is very important for knowing whether future Europa explorers could have a chance to actually detect life from space without probing Europa's ocean," said lead author Gregor Steinbrügge, a postdoctoral researcher at Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth).

The researchers focused their analyses on Manannán, an 18-mile-wide crater on Europa that was created by an impact with another celestial object some tens of millions of years ago. Reasoning that such a collision would have generated a tremendous amount of heat, they modeled how melting and subsequent freezing of a water pocket within the icy shell could have caused the water to erupt.

"The comet or asteroid hitting the ice shell was basically a big experiment which we're using to construct hypotheses to test," said co-author Don Blankenship, senior research scientist at the University of Texas Institute for Geophysics (UTIG) and principal investigator of the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) instrument that will fly on Europa Clipper. "The polar and planetary sciences team at UTIG are all currently dedicated to evaluating the ability of this instrument to test those hypotheses."

The model indicates that as Europa's water transformed into ice during the later stages of the impact, pockets of water with increased salinity could be created in the moon's surface. Furthermore, these salty water pockets can migrate sideways through Europa's ice shell by melting adjacent regions of less brackish ice, and consequently become even saltier in the process.

"We developed a way that a water pocket can move laterally - and that's very important," Steinbrügge said. "It can move along thermal gradients, from cold to warm, and not only in the down direction as pulled by gravity."

A salty driver

The model predicts that when a migrating brine pocket reached the center of Manannán crater, it became stuck and began freezing, generating pressure that eventually resulted in a plume, estimated to have been over a mile high. The eruption of this plume left a distinguishing mark: a spider-shaped feature on Europa's surface that was observed by Galileo imaging and incorporated in the researchers' model.

"Even though plumes generated by brine pocket migration would not provide direct insight into Europa's ocean, our findings suggest that Europa's ice shell itself is very dynamic," said co-lead author Joana Voigt, a graduate research assistant at the University of Arizona, Tucson.

The relatively small size of the plume that would form at Manannán indicates that impact craters probably can't explain the source of other, larger plumes on Europa that have been hypothesized based on Hubble and Galileo data, the researchers say. But the process modeled for the Manannán eruption could happen on other icy bodies - even without an impact event.

"Brine pocket migration is not uniquely applicable to Europan craters," Voigt said. "Instead the mechanism might provide explanations on other icy bodies where thermal gradients exist."

The study also provides estimates of how salty Europa's frozen surface and ocean may be, which in turn could affect the transparency of its ice shell to radar waves. The calculations, based on imaging from Galileo from 1995 to 1997, show Europa's ocean may be about one-fifth as salty as Earth's ocean - a factor that will improve the capacity for the Europa Clipper mission's radar sounder to collect data from its interior.

The findings may be discouraging to astrobiologists hoping Europa's erupting plumes might contain clues about the internal ocean's capacity to support life, given the implication that plumes do not have to connect to Europa's ocean. However, the new model offers insights toward untangling Europa's complex surface features, which are subject to hydrological processes, the pull of Jupiter's gravity and hidden tectonic forces within the icy moon.

"This makes the shallow subsurface - the ice shell itself - a much more exciting place to think about," said co-author Dustin Schroeder, an assistant professor of geophysics at Stanford. "It opens up a whole new way of thinking about what's happening with water near the surface."

###

Schroeder is also an assistant professor, by courtesy, of electrical engineering and a center fellow, by courtesy, at the Stanford Woods Institute for the Environment. Co-authors include Krista Soderlund, Natalie Wolfenbarger and Duncan Young from the University of Texas at Austin; Christopher Hamilton from the University of Arizona, Tucson; and Steven Vance from NASA's Jet Propulsion Laboratory.

The research was supported by the G. Unger Vetlesen Foundation. A portion of the work was carried out by the Jet Propulsion Laboratory, Caltech, under a contract with NASA.

Galaxies have gotten hotter as they've gotten older

Study of 10 billion years of microwaves reveals a warming predicted by dark matter theory

JOHNS HOPKINS UNIVERSITY

Research News

 

IMAGE: BRICE MÉNARD OF JOHNS HOPKINS AND YI-KUAN CHIANG OF OHIO STATE UNIVERSITY. view more 

CREDIT: RON SCHEFFLER

Who says you can't get hotter with age?

Researchers from Johns Hopkins University and other institutions have found that, on average, the temperature of galaxy clusters today is 4 million degrees Fahrenheit. That is 10 times hotter than 10 billion years ago, and four times hotter than the Sun's outermost atmosphere called the corona. The findings are published in the Astrophysical Journal.

"We have measured temperatures throughout the history of the universe," said Brice Ménard, a Johns Hopkins professor of physics and astronomy. "As time has gone on, all those clusters of galaxies are getting hotter and hotter because their gravity pulls more and more gas toward them."

Yi-Kuan Chiang, lead author of the study who was a Johns Hopkins post-doctoral researcher until moving to Ohio State University last year, added: "This drag is so violent that more and more gas is shocked and heated up."

Imagine all those gas atoms being sucked towards galaxies like they were myriads of meteoroids piercing Earth's atmosphere, Ménard said. They accelerate as gravity pulls them toward the Earth's surface and heat up due to friction with the atmosphere before burning into what are seen as shooting stars, he added. This pattern of heating due to gravitational forces can be applied to entire galaxies, clusters of galaxies and beyond into the "large scale structures" of the universe formed by gravity - a theory attributed to James Peebles, the 2019 Nobel laureate in physics.

"Our measurements are a great confirmation of that theory," Ménard said.

To perform this analysis, the team used data collected by the astronomical community over two decades, first from a telescope on the ground that conducted the Sloan Digital Sky Survey and then the Planck mission, a space telescope led by the European Space Agency.

The team used a technique that Ménard developed with Chiang. With it, they estimated the "redshift" of gas concentrations seen in images of microwave light going back in time all the way to 10 billion years ago. "Redshift" describes the way wavelengths of light lengthen due to the expansion of the universe. The farther away something is, the longer its wavelength - and the older its origin.

The method allowed them to measure the gradual increase in the gas temperature as a function of the age of the universe. This trend is also predicted by numerical simulations showing how dark matter and the atoms present in the gas evolve with time. As illustrated in the figure, these visualizations show gas temperatures changing from a cool blue canvas from 10 billion years ago into one speckled with hot red today.

The warming of the universe has nothing to do with climate warming on Earth, Ménard said. It is a consequence of gravitational attraction that had been predicted but which now can be precisely measured with these novel techniques.

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Researchers from the University of Tokyo and the Max Planck Institute for Astrophysics contributed to this work, which was supported in part by NSF grant AST1313302 and NASA grant NNX16AF64G (Y.C., B.M.). Other support has come from the Excellence Cluster ORIGINS, which is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy--EXC-2094-390783311 (E.K.), and JSPS KAKENHI grant Nos. JP15H05896 (R.M., E.K.) and JP20K14515 (R.M.).

Reporters interested in speaking with Ménard can call Doug Donovan at 443-462-2947 or email him at dougdonovan@jhu.edu.

Johns Hopkins University news releases are available online, as is information for reporters. To arrange a video or audio interview with a Johns Hopkins expert, contact a media representative listed above or visit our studio web page. Find more Johns Hopkins stories on the Hub.

The universe is getting hot, hot, hot, a new study suggests

Temperature has increased about 10 times over the last 10 billion years

OHIO STATE UNIVERSITY

Research News

 

COLUMBUS, Ohio -- The universe is getting hotter, a new study has found.

The study, published Oct. 13 in the Astrophysical Journal, probed the thermal history of the universe over the last 10 billion years. It found that the mean temperature of gas across the universe has increased more than 10 times over that time period and reached about 2 million degrees Kelvin today -- approximately 4 million degrees Fahrenheit.

"Our new measurement provides a direct confirmation of the seminal work by Jim Peebles -- the 2019 Nobel Laureate in Physics -- who laid out the theory of how the large-scale structure forms in the universe," said Yi-Kuan Chiang, lead author of the study and a research fellow at The Ohio State University Center for Cosmology and AstroParticle Physics.

The large-scale structure of the universe refers to the global patterns of galaxies and galaxy clusters on scales beyond individual galaxies. It is formed by the gravitational collapse of dark matter and gas.

"As the universe evolves, gravity pulls dark matter and gas in space together into galaxies and clusters of galaxies," Chiang said. "The drag is violent -- so violent that more and more gas is shocked and heated up."

The findings, Chiang said, showed scientists how to clock the progress of cosmic structure formation by "checking the temperature" of the universe.

The researchers used a new method that allowed them to estimate the temperature of gas farther away from Earth -- which means further back in time -- and compare them to gases closer to Earth and near the present time. Now, he said, researchers have confirmed that the universe is getting hotter over time due to the gravitational collapse of cosmic structure, and the heating will likely continue.

To understand how the temperature of the universe has changed over time, researchers used data on light throughout space collected by two missions, Planck and the Sloan Digital Sky Survey. Planck is the European Space Agency mission that operates with heavy involvement from NASA; Sloan collects detailed images and light spectra from the universe.

They combined data from the two missions and evaluated the distances of the hot gases near and far via measuring redshift, a notion that astrophysicists use to estimate the cosmic age at which distant objects are observed. ("Redshift" gets its name from the way wavelengths of light lengthen. The farther away something is in the universe, the longer its wavelength of light. Scientists who study the cosmos call that lengthening the redshift effect.)

The concept of redshift works because the light we see from objects farther away from Earth is older than the light we see from objects closer to Earth -- the light from distant objects has traveled a longer journey to reach us. That fact, together with a method to estimate temperature from light, allowed the researchers to measure the mean temperature of gases in the early universe -- gases that surround objects farther away -- and compare that mean with the mean temperature of gases closer to Earth -- gases today.

Those gases in the universe today, the researchers found, reach temperatures of about 2 million degrees Kelvin -- approximately 4 million degrees Fahrenheit, around objects closer to Earth. That is about 10 times the temperature of the gases around objects farther away and further back in time.

The universe, Chiang said, is warming because of the natural process of galaxy and structure formation. It is unrelated to the warming on Earth. "These phenomena are happening on very different scales," he said. "They are not at all connected."

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This study was completed in collaborations with researchers at the Kavli Institute for the Physics and Mathematics of the Universe, Johns Hopkins University, and the Max Planck Institute for Astrophysics.

CONTACT: Yi-Kuan Chiang, chiang.224@osu.edu

Written by: Laura Arenschield, arenschield.2@osu.edu

SwRI scientist studies tiny craters on Bennu boulders to understand asteroid's age

Scientists inferred Bennu's sojourn in the inner Solar System at 1.75 million years

SOUTHWEST RESEARCH INSTITUTE

Research News

 

IMAGE: SWRI AND THE UNIVERSITY OF ARIZONA STUDIED CENTIMETER- TO METER-SIZED CRATERS ON BOULDERS SCATTERED AROUND THE SURFACE OF THE NEAR-EARTH ASTEROID BENNU. THIS COMPOSITE SHOWS THE CASCADING RIM OF AN... view more 

CREDIT: UNIVERSITY OF ARIZONA/JOHNS HOPKINS APL/YORK UNIVERSITY

SAN ANTONIO -- Nov. 10, 2020 -- Last week NASA snagged a sample from the surface of asteroid Bennu, an Empire State Building-sized body that Southwest Research Institute scientists have helped map with nearly unprecedented precision. Using orbital data from the OSIRIS-REx spacecraft, researchers measured centimeter- to meter-sized craters on the boulders scattered around its rugged surface to shed light on the age of the asteroid.

While the collected sample will yield enormous scientific value when it is returned to Earth in 2023, a key job for scientists during the time in orbit at Bennu was to understand the geology of the entire asteroid to provide important context for the sample. This provides insights into all the processes that might have affected the nature of the sample.

"The amazing data collected by OSIRIS-REx at asteroid Bennu have allowed us to not just find impact craters across its surface, but to actually find and study the craters on the surfaces of boulders," said SwRI's Dr. Kevin Walsh, a coauthor of "Bennu's near-Earth lifetime of 1.75 million years inferred from craters on its boulders," published October 26 in the journal Nature. "The craters that we could observe and measure on the surfaces of boulders allowed us to estimate their strengths, a first-of-its-kind measurement."

Bennu is a dark rubble pile held together by gravity and thought to be an asteroid remnant created following a collision involving a larger main-belt object. Boulders are scattered across its heavily cratered surface, indicating that it has had a rough-and-tumble life since being liberated from its much larger parent asteroid millions or even billions of years ago. Scientists use studies of impact craters to determine the ages of planetary surfaces.

Team members from the University of Arizona developed a mathematical formula that allows researchers to calculate the maximum impact energy a boulder of a given size and strength could endure before being smashed.

Walsh, lead author Dr. Ron Ballouz (a postdoctoral fellow at the University of Arizona), and colleagues brought together an understanding of the number of craters, the strength of the materials impacted, and the numbers of impactors to help constrain the chronology of Bennu's existence in the inner Solar System at 1.75 million years. Since the spacecraft arrived at Bennu in 2018, scientists have been characterizing the asteroid's composition from orbit and comparing it to other asteroids and meteorites. Now NASA has collected an actual sample of its surface that scientists will be able to study.

"We held our breath as the spacecraft touched the asteroid's boulder-strewn surface with a robotic arm for a few seconds to collect a sample of rocks and dust on October 20 -- a first for NASA," Walsh said. "Hitting pay dirt on the first attempt is fantastic. We look forward to learning so much more when the sample arrives back at Earth in 2023."

The manuscript describes a method for measuring the strength of solid objects uses remote observations of craters on surface boulders. Determining the strengths of boulders on asteroid surfaces is a leap forward from measuring the strength of much smaller meteorites, which have the bias of surviving passage through Earth's atmosphere.

"The rocks tell their history through the craters they accumulated over time," said Ballouz. "The boulders serve as witnesses to Bennu's time as a near-Earth asteroid, validating decades of dynamical studies of the lifetime of near-Earth asteroids."

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For more information, visit https://www.swri.org/planetary-science.

Scientists have discovered an ancient lake bed deep beneath the Greenland ice

Inaccessible for now, unique site may hold secrets of past

EARTH INSTITUTE AT COLUMBIA UNIVERSITY

Research News

 

IMAGE: THE LARGELY FEATURELESS SURFACE OF THE GREENLAND ICE SHEET, AS SEEN FROM THE WINDOW OF A P3 AIRCRAFT CARRYING GEOPHYSICAL INSTRUMENTS AIMED AT DETECTING GEOLOGIC FEATURES UNDERNEATH. view more 

CREDIT: KIRSTY TINTO/LAMONT-DOHERTY EARTH OBSERVATORY

Scientists have detected what they say are the sediments of a huge ancient lake bed sealed more than a mile under the ice of northwest Greenland--the first-ever discovery of such a sub-glacial feature anywhere in the world. Apparently formed at a time when the area was ice-free but now completely frozen in, the lake bed may be hundreds of thousands or millions of years old, and contain unique fossil and chemical traces of past climates and life. Scientists consider such data vital to understanding what the Greenland ice sheet may do in coming years as climate warms, and thus the site makes a tantalizing target for drilling. A paper describing the discovery is in press at the journal Earth and Planetary Science Letters.

"This could be an important repository of information, in a landscape that right now is totally concealed and inaccessible," said Guy Paxman, a postdoctoral researcher at Columbia University's Lamont-Doherty Earth Observatory and lead author of the report. "We're working to try and understand how the Greenland ice sheet has behaved in the past. It's important if we want to understand how it will behave in future decades." The ice sheet, which has been melting at an accelerating pace in recent years, contains enough water to raise global sea levels by about 24 feet.

The researchers mapped out the lake bed by analyzing data from airborne geophysical instruments that can read signals that penetrate the ice and provide images of the geologic structures below. Most of the data came from aircraft flying at low altitude over the ice sheet as part of NASA's Operation IceBridge.

The team says the basin once hosted a lake covering about 7,100 square kilometers (2,700 square miles), about the size of the U.S. states of Delaware and Rhode Island combined. Sediments in the basin, shaped vaguely like a meat cleaver, appear to range as much as 1.2 kilometers (three quarters of a mile) thick. The geophysical images show a network of at least 18 apparent onetime stream beds carved into the adjoining bedrock in a sloping escarpment to the north that must have fed the lake. The image also show at least one apparent outlet stream to the south. The researchers calculate that the water depth in the onetime lake ranged from about 50 meters to 250 meters (a maximum of about 800 feet).

In recent years, scientists have found existing subglacial lakes in both Greenland and Antarctica, containing liquid water sandwiched in the ice, or between bedrock and ice. This is the first time anyone has spotted a fossil lake bed, apparently formed when there was no ice, and then later covered over and frozen in place. There is no evidence that the Greenland basin contains liquid water today.

Paxman says there is no way to tell how old the lake bed is. Researchers say it is likely that ice has periodically advanced and retreated over much of Greenland for the last 10 million years, and maybe going back as far as 30 million years. A 2016 study led by Lamont-Doherty geochemist Joerg Schaefer has suggested that most of the Greenland ice may have melted for one or more extended periods some time in the last million years or so, but the details of that are sketchy. This particular area could have been repeatedly covered and uncovered, Paxman said, leaving a wide range of possibilities for the lake's history. In any case, Paxman says, the substantial depth of the sediments in the basin suggest that they must have built up during ice-free times over hundreds of thousands or millions of years.

"If we could get at those sediments, they could tell us when the ice was present or absent," he said.

The researchers assembled a detailed picture of the lake basin and its surroundings by analyzing radar, gravity and magnetic data gathered by NASA. Ice-penetrating radar provided a basic topographic map of the earth' s surface underlying the ice. This revealed the outlines of the smooth, low-lying basin, nestled among higher-elevation rocks. Gravity measurements showed that the material in the basin is less dense than the surrounding hard, metamorphic rocks--evidence that it is composed of sediments washed in from the sides. Measurements of magnetism (sediments are less magnetic than solid rock) helped the team map the depths of the sediments.

The researchers say the basin may have formed along a now long-dormant fault line, when the bedrock stretched out and formed a low spot. Alternatively, but less likely, previous glaciations may have carved out the depression, leaving it to fill with water when the ice receded.

What the sediments might contain is a mystery. Material washed out from the edges of the ice sheet have been found to contain the remains of pollen and other materials, suggesting that Greenland may have undergone warm periods during the last million years, allowing plants and maybe even forests to take hold. But the evidence is not conclusive, in part because it is hard to date such loose materials. The newly discovered lake bed, in contrast, could provide an intact archive of fossils and chemical signals dating to a so-far unknown distant past.

The basin "may therefore be an important site for future sub-ice drilling and the recovery of sediment records that may yield valuable insights into the glacial, climatological and environmental history" of the region, the researchers write. With the top of the sediments lying 1.8 kilometers below the current ice surface (1.1 miles), such drilling would be daunting, but not impossible. In the 1990s, researchers penetrated almost 2 miles into the summit of the Greenland ice sheet and recovered several feet of bedrock--at the time, the deepest ice core ever drilled. The feat, which took five years, has not since been repeated in Greenland, but a new project aimed at reaching shallower bedrock in another part of northwest Greenland is being planned for the next few years.

CAPTION

A newly forming lake at the edge of the Greenland ice sheet, exposing sediments released by the ice. Such lake beds are becoming common as the ice recedes.

CAPTION

Using geophysical instruments, scientists have mapped a huge ancient lake basin (outlined here in red) below the Greenland ice, covering about 2,700 square miles). Redder colors signify higher elevations, green ones lower. A stream system incised into the bedrock that once fed the lake is shown in blue.

CREDIT

Adapted from Paxman et al., EPSL, 2020

The study was coauthored Jacqueline Austermann and Kirsty Tinto, both also based at Lamont-Doherty Earth Observatory. The research was supported by the U.S. National Science Foundation.

Scientist contacts:

Guy Paxman gpaxman@ldeo.columbia.edu
Jacqueline Austermann jackya@ldeo.columbia.edu
Kirsty Tinto tinto@ldeo.columbia.edu

More information: Kevin Krajick, Senior editor, science news, The Earth Institute kkrajick@ei.columbia.edu 212-854-9729

Lamont-Doherty Earth Observatory is Columbia University's home for Earth science research. Its scientists develop fundamental knowledge about the origin, evolution and future of the natural world, from the planet's deepest interior to the outer reaches of its atmosphere, on every continent and in every ocean, providing a rational basis for the difficult choices facing humanity. http://www.ldeo.columbia.edu | @LamontEarth

The Earth Institute, Columbia University mobilizes the sciences, education and public policy to achieve a sustainable earth. http://www.earth.columbia.edu.

Jacky dragon moms' time in the sun affects their kids

A study of maternal body condition potentially links environmental temperature to offspring traits

UNIVERSITY OF CHICAGO PRESS JOURNALS

Research News

 

IMAGE: JACKY DRAGON view more 

CREDIT: UNSW SYDNEY. PHOTO: LISA SCHWANZ.

A new study conducted at the University of New South Wales and published in the November/December 2020 issue of Physiological and Biochemical Zoology sheds light on a possible connection between an animal's environmental conditions and the traits of its offspring. The study, Maternal Temperature, Corticosterone, and Body Condition as Mediators of Maternal Effects in Jacky Dragons (Amphibolurus muricatus), focused on how maternal condition and stress hormone (corticosterone) levels in jacky dragons (Amphibolurus muricatus) potentially translate a mom's heat exposure to effects on her offspring.

Ectothermic species, such as lizards, often rely on external heat sources to manage their body temperature. It turns out that maternal temperature can affect offspring traits such as gender and the rate of growth. While those trait changes have been documented, the means by which information passes from parent to offspring are poorly known.

Maternal effects theory, in particular, has helped answer a number of important biological questions related to evolution. However, the mechanisms for how those effects take place has not been nearly as well-developed, leading to unanswered questions concerning proximate physical causes.

"Mechanisms by which thermal information can be passed onto offspring have been underexplored," writes the study's author, Gracie Liu. "Here, we investigated corticosterone as a potential mediator of thermal maternal effects."

The study placed female jacky dragons in two different thermal regimes - one that exposed the subject to 7 hours of thermal basking treatments each day, the other exposing the subject to 11 hours of the same treatment each day - then measured the levels of corticosterone in the subjects' blood and examined any possible relation connected to their offspring.

Corticosterone is a steroid hormone associated with the "stress" response, energy mobilization, and suppression of the immune system. Such hormones often serve as a potential connection between offspring phenotypes and the environment of the mother, since they transfer from mother to offspring and can play a role in physiology, behavior and similar factors.

The results indicated that such "thermal opportunity" does have an effect on mothers and their offspring. Specifically, lizards exposed to the longer 11-hour regime show significantly higher corticosterone levels in their bloodstream than those exposed to the 7-hour regime.

However, it was corticosterone's connection to maternal body condition that led to increased reproductive output - which included both the number of eggs in a subject's given clutch and the overall size of the clutch - as well as an increased size in offspring at hatching. It did not, however, have a corresponding effect on the growth of those offspring or their gender.

More specifically, the basking treatment appeared to be interrelated with maternal corticosterone levels and body condition. That, in turn, had an interactive effect on the resulting clutch, which suggests that the combination of condition, corticosterone and overall maternal temperature could be conveying information about the mother's external environment into her offspring.

"These findings indicate that thermal opportunity alters physiology," Liu writes. "With potential consequences for fitness."

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This study was funded by the Australian Research Council and the UNSW School of BEES.