Wednesday, July 05, 2023

Black Americans may face relatively accelerated biological aging because they tend to experience lower socioeconomic status, more neighborhood deprivation and higher air pollution than White Americans



Peer-Reviewed Publication

PLOS

Contributions of neighborhood social environment and air pollution exposure to Black-White disparities in epigenetic aging 

IMAGE: BLACK AMERICANS MAY FACE RELATIVELY ACCELERATED BIOLOGICAL AGING BECAUSE THEY TEND TO EXPERIENCE LOWER SOCIOECONOMIC STATUS, MORE NEIGHBORHOOD DEPRIVATION AND HIGHER AIR POLLUTION THAN WHITE AMERICANS. view more 

CREDIT: CRAIG ADDERLEY, PEXELS, CC0 (HTTPS://CREATIVECOMMONS.ORG/PUBLICDOMAIN/ZERO/1.0/)



Article URL:  https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0287112

Article Title: Contributions of neighborhood social environment and air pollution exposure to Black-White disparities in epigenetic aging

Author Countries: USA

Funding: This work was supported by National Institute on Aging: R01-AG066152 (CM), R01- AG070885 (RB), P30-AG072979 (CM). Additional support includes Pennsylvania Department of Health (2019NF4100087335; CM), and Penn Institute on Aging (CM). National Institute on Aging: https://www.nia.nih.gov Pennsylvania Department of Health: https://www.health.pa.gov/Pages/default.aspx Penn Institute on Aging: https://www.med.upenn.edu/aging/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Research led by UW undergrad shows ultrafine air pollution reflects Seattle’s redlining history

Peer-Reviewed Publication

UNIVERSITY OF WASHINGTON




Despite their invisibly small size, ultrafine particles have become a massive concern for air pollution experts. These tiny pollutants — typically spread through wildfire smoke, vehicle exhaust, industrial emissions and airplane fumes — can bypass some of the body’s built-in defenses, carrying toxins to every organ or burrowing deep in the lungs.  

New research from the University of Washington found that those effects aren’t felt equitably in Seattle. The most comprehensive study yet of long-term ultrafine particle exposure found that concentrations of this tiny pollutant reflect the city’s decades-old racial and economic divides.  

The study, published July 5 in Environmental Health Perspectives, also found that racial and socioeconomic disparities in ultrafine particle exposure are larger than those observed in more commonly studied pollutants, like fine particles (PM 2.5) and nitrogen dioxide (NO2). 

The study used mobile monitoring — a car loaded with air pollution sensors driving around the city for the better part of a year — to examine long-term average levels of four pollutants: soot (or black carbon), fine particles (PM 2.5), nitrogen dioxide (NO2) and ultrafine particles. Researchers found the highest concentrations of all four pollutants on census blocks with median household incomes under $20,000 and those with proportionately larger Black populations.  

Disparities in concentrations of ultrafine particles — which are less than 0.1 micron in diameter, or 700 times thinner than the width of a single human hair — were especially stark. Blocks with median incomes under $20,000 had long-term UFP concentrations 40% higher than average. Blocks where median incomes are over $110,000, meanwhile, saw UFP concentrations 16% lower than average.  

“We found greater disparities with this pollutant of emerging interest, a pollutant that hasn’t been well-characterized. That’s very interesting,” said senior author Lianne Sheppard, a UW professor in the Department of Environmental and Occupational Health Sciences. “Our work has shown the highest ultrafine particle concentrations are north of the airport and below common aircraft landing paths, downtown, and south of downtown where there are port and other industrial activities.” 

The study also found that modern-day air pollution disparities mirror Seattle’s history of redlining, the racist practice that denied racial minorities and low-income residents access to bank loans, homeownership and other wealth-building opportunities in more “desirable” areas. The practice shaped American cities throughout the early 20th century, building a foundation of segregation and environmental racism. 

Today, neighborhoods once classified as “hazardous” are still exposed to higher concentrations of pollution than those once labeled “desirable,” the study found. This was true for all sizes of particles. The spatial disparities were largest, however, in Seattle neighborhoods that received no label because they were once considered industrial areas. 

In those previously industrial areas, ultrafine particle concentrations were 49% above average.  

“These results are important because air pollution exposure has been shown to lead to detrimental health effects, and these health effects disproportionately impact racialized and low-income communities,” said Kaya Bramble, the study’s lead author, who graduated from the UW in 2022 with a degree in industrial and systems engineering. “Notably, air pollution is just one factor, and there are plenty of other examples of how systemic racism is detrimental to people’s health and well-being.” 

Bramble said the results didn’t surprise her. She was raised in Tacoma, in a neighborhood near Interstate 5, where the constant crush of cars and diesel trucks spewed pollution into the air. And as a student journalist at the UW, she researched the relationship between redlining, green spaces, heat and air pollution.  

“In the case of air pollution exposures, these policies affect the health of real people. I think at a time where the teaching of systemic racism is a controversial topic in this country, being ignorant is not going to reduce the number of children who suffer from asthma due to air pollution,” Bramble said. “Instead, I hope we can have conversations about how past policies affect us today, to drive efforts toward a healthier, sustainable society.” 

Bramble proposed and carried out this study for the Supporting Undergraduate Research Experiences in Environmental Health grant program, which provides National Institute of Environmental Health Sciences funding and mentorship to undergraduates from underrepresented backgrounds to pursue research. She joined the program in June 2020 under Sheppard’s mentorship.  

Other UW authors are Magali Blanco, Annie Doubleday and Amanda Gassett of the Department of Environmental and Occupational Health Sciences, Anjum Hajat of the Department of Epidemiology and Julian Marshall of the Department of Civil and Environmental Engineering.  

For more information, contact Sheppard at sheppard@uw.edu

Large sub-surface granite formation signals ancient volcanic activity on Moon's dark side

Microwave frequency data from lunar orbiter reveals deposit of cooled magma beneath a volcano that likely erupted 3.5 billion years ago


Peer-Reviewed Publication

SOUTHERN METHODIST UNIVERSITY

Compton-Belkovich 

IMAGE: A TEAM OF SCIENTISTS USED MICROWAVE FREQUENCY DATA TO MEASURE HEAT BELOW THE SURFACE OF A SUSPECTED VOLCANIC FEATURE ON THE MOON KNOWN AS COMPTON-BELKOVICH. view more 

CREDIT: NATURE



DALLAS (SMU) – A large formation of granite discovered below the lunar surface likely was formed from the cooling of molten lava that fed a volcano or volcanoes that erupted early in the Moon’s history – as long as 3.5 billion years ago.

A team of scientists led by Matthew Siegler, an SMU research professor and research scientist with the Planetary Science Institute, has published a study in Nature that used microwave frequency data to measure heat below the surface of a suspected volcanic feature on the Moon known as Compton-Belkovich. The team used the data to determine that the heat being generated below the surface is coming from a concentration of radioactive elements that can only exist on the Moon as granite.

Granites are the igneous rock remnants of the plumbing systems below extinct volcanos. The granite formation left when lava cools without erupting is known as a batholith.

“Any big body of granite that we find on Earth used to feed a big bunch of volcanoes, much like a large system is feeding the Cascade volcanoes in the Pacific Northwest today,” Siegler said. “Batholiths are much bigger than the volcanoes they feed on the surface. For example, the Sierra Nevada mountains are a batholith, left from a volcanic chain in the western United States that existed long ago.”

The lunar batholith is located in a region of the Moon previously identified as a volcanic complex, but researchers are surprised at its size, with an estimated diameter of 50 kilometers.

Granite is somewhat common on Earth, and its formation is generally driven by water and plate tectonics, which aid in creating large melt bodies below the Earth’s surface. However, granites are extremely rare on the Moon, which lacks these processes.

Finding this granite body helps explain how the early lunar crust formed.

“If you don’t have water it takes extreme situations to make granite,” Siegler said. “So, here’s this system with no water, and no plate tectonics – but you have granite.

Was there water on the moon – at least in this one spot?  Or was it just especially hot?”

Research team members included Jianquing Fang, from the Planetary Science Institute; Katelyn Lehman-Franco, Rita Economos and Mackenzie White from SMU; Jeffrey Andrews-Hanna from Southwest Research Institute; Michael St. Clair and Chase Million from Million Concepts; James Head III from Brown University and Timothy Glotch from Stony Brook University.

The work was funded through NASA’s Lunar Data Analysis Program and work related to the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer.

Data for the study was obtained from public data released from two Chinese lunar orbiters, Chang’E-1 in 2010 and Chang’E-2 in 2012, carrying four-channel microwave radiometer instruments. The original Chang’E‐1 and Chang’E-2 MRM data can be downloaded from: http://moon.bao.ac.cn/index_en.jsp.

Siegler will be presenting the team’s research at the upcoming Goldschmidt Conference, scheduled for July 9-14 in Lyon, France.

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New glass cuts carbon footprint by nearly half and is 10x more damage resistant

Business Announcement

PENN STATE

LionGlass 

IMAGE: A SAMPLE OF LIONGLASS, A NEW TYPE OF GLASS ENGINEERED BY RESEARCHERS AT PENN STATE THAT REQUIRES SIGNIFICANTLY LESS ENERGY TO PRODUCE AND IS MUCH MORE DAMAGE RESISTANT THAN STANDARD SODA LIME SILICATE GLASS. view more 

CREDIT: ADRIENNE BERARD/PENN STATE.




UNIVERSITY PARK, Pa. — Worldwide, glass manufacturing produces at least 86 million tons of carbon dioxide every year. A new type of glass promises to cut this carbon footprint in half. The invention, called LionGlass and engineered by researchers at Penn State, requires significantly less energy to produce and is much more damage resistant than standard soda lime silicate glass. The research team recently filed a patent application as a first step toward bringing the product to market.

“Our goal is to make glass manufacturing sustainable for the long term,” said John Mauro, Dorothy Pate Enright Professor of Materials Science and Engineering at Penn State and lead researcher on the project. “LionGlass eliminates the use of carbon-containing batch materials and significantly lowers the melting temperature of glass.”

Soda lime silicate glass, the common glass used in everyday items from windows to glass tableware, is made by melting three primary materials: quartz sand, soda ash and limestone. Soda ash is sodium carbonate and limestone is calcium carbonate, both of which release carbon dioxide (CO2), a heat-trapping greenhouse gas, as they are melted.  

“During the glass melting process, the carbonates decompose into oxides and produce carbon dioxide, which gets released into the atmosphere,” Mauro said.

But the bulk of the CO2 emissions come from the energy required to heat furnaces to the high temperatures needed for melting glass. With LionGlass, the melting temperatures are lowered by about 300 to 400 degrees Celsius, Mauro explained, which leads to a roughly 30% reduction in energy consumption compared to conventional soda lime glass.

Not only is LionGlass easier on the environment, it’s also much stronger than conventional glass. The researchers said they were surprised to find that the new glass, named after Penn State’s Nittany Lion mascot, possesses significantly higher crack resistance compared to conventional glass.

Some of the team’s glass compositions had such a strong crack resistance that the glass would not crack, even under a one kilogram-force load from a Vickers diamond indenter. LionGlass is at least 10 times as crack-resistant compared to standard soda lime glass, which forms cracks under a load of about 0.1 kilograms force. The researchers explained that the limits of LionGlass have not yet been found, because they reached the maximum load allowed by the indentation equipment.

“We kept increasing the weight on LionGlass until we reached the maximum load the equipment will allow,” said Nick Clark, a postdoctoral fellow in Mauro’s lab. “It simply wouldn’t crack.”

Mauro explained that crack resistance one of the most important qualities to test for in glass, because it is how the material eventually fails. Over time, glass develops microcracks along the surface, which become weak points. When a piece of glass breaks, it’s due to weaknesses caused by existing microcracks. Glass that is resistant to forming microcracks in the first place is especially valuable, he added.

“Damage resistance is a particularly important property for glass,” Mauro said. “Think about all the ways we rely on the strength of glass, in the automotive industry and electronics industry, architecture, and communication technology like fiber optic cables. Even in health care, vaccines are stored in strong, chemically resistant glass packaging.”

Mauro is hoping that the improved strength of LionGlass means the products created from it can be lighter weight. Since LionGlass is 10 times more damage resistant than current glass, it could be significantly thinner.

“We should be able to reduce the thickness and still get the same level of damage resistance,” Mauro said. “If we have a lighter-weight product, that is even better for the environment, because we use less raw materials and need less energy to produce it. Even downstream, for transportation, that reduces the energy required to transport the glass, so it's a winning situation for everyone.”

Mauro notes that the research team is still evaluating the potential of LionGlass. They have filed a patent application for the entire family of glass, which means there are many compositions within the LionGlass family, each with its own distinct properties and potential applications. They are now in the process of exposing various compositions of LionGlass to an array of chemical environments to study how it reacts. The results will help the team develop a better understanding of how LionGlass can be used throughout the world.

“Humans learned how to manufacture glass more than 5,000 years ago and since then it has been critical to bringing modern civilization to where it is today,” Mauro said. “Now, we are at a point in time when we need it to help shape the future, as we face global challenges such as environmental issues, renewable energy, energy efficiency, health care and urban development. Glass can play a vital role in solving these issues, and we are ready to contribute.”

Earth formed from dry, rocky building blocks

Peer-Reviewed Publication

CALIFORNIA INSTITUTE OF TECHNOLOGY




Billions of years ago, in the giant disk of dust, gas, and rocky material that orbited our young sun, larger and larger bodies coalesced to eventually give rise to the planets, moons, and asteroids we see today. Scientists are still trying to understand the processes by which planets, including our home planet, were formed. One way researchers can study how Earth formed is to examine the magmas that flow up from deep within the planet’s interior. The chemical signatures from these samples contain a record of the timing and the nature of the materials that came together to form Earth—analogous to how fossils give us clues about Earth's biological past.

Now, a study from Caltech shows that the early Earth accreted from hot and dry materials, indicating that our planet's water—the crucial component for the evolution of life—must have arrived late in the history of Earth's formation.

The study, involving an international team of researchers, was conducted in the laboratories of Francois Tissot, assistant professor of geochemistry and Heritage Medical Research Institute Investigator; and Yigang Zhang of the University of Chinese Academy of Sciences. A paper describing the research appears in the journal Science Advances. Caltech graduate student Weiyi Liu is the paper's first author.

Though humans do not have a way to journey into the interior of our planet, the rocks deep within the earth can naturally make their way to the surface in the form of lavas. The parental magmas of these lavas can originate from different depths within Earth, such as the upper mantle, which begins around 15 kilometers under the surface and extends for about 680 kilometers; or the lower mantle, which spans from a depth of 680 kilometers all the way to the core–mantle boundary at about 2,900 kilometers below our feet. Like sampling different layers of a cake—the frosting, the filling, the sponge—scientists can study magmas originating from different depths to understand the different "flavors" of Earth’s layers: the chemicals found within and their ratios with respect to one another.

Because the formation of Earth was not instantaneous and instead involved materials accreting over time, samples from the lower mantle and upper mantle give different clues to what was happening over time during Earth's accretion. In the new study, the team found that the early Earth was primarily composed of dry, rocky materials: chemical signatures from deep within the planet showed a lack of so-called volatiles, which are easily evaporated materials like water and iodine. In contrast, samples of the upper mantle revealed a higher proportion of volatiles, three times of those found in the lower mantle. Based on these chemical ratios, Liu created a model that showed Earth formed from hot, dry, rocky materials, and that a major addition of life-essential volatiles, including water, only occurred during the last 15 percent (or less) of Earth's formation.

The study is a crucial contribution to theories of planet formation, a field which has undergone several paradigm shifts in recent decades and is still characterized by vigorous scientific debate. In this context, the new study makes important predictions for the nature of the building blocks of other terrestrial planets—Mercury and Venus—which would be expected to have formed from similarly dry materials. 

"Space exploration to the outer planets is really important because a water world is probably the best place to look for extraterrestrial life," Tissot says. "But the inner solar system shouldn't be forgotten. There hasn't been a mission that's touched Venus’s surface for nearly 40 years, and there has never been a mission to the surface of Mercury. We need to be able to study those worlds to better understand how terrestrial planets such as Earth formed."

The paper is titled "I/Pu reveals Earth mainly accreted from volatile-poor differentiated planetesimals." In addition to Liu and Tissot, co-authors are Zhang of the University of Chinese Academy of Sciences; Guillaume Avice of the Université Paris Cité, Institut de physique du globe de Paris; Zhilin Ye of the Chinese Academy of Sciences; and Qing-Zhu Yin of the University of California, Davis. Funding was provided by the Chinese Academy of Sciences, the National Science Foundation, a Packard Fellowship for Science and Engineering, the Heritage Medical Research Institute, and Caltech.

Lasering lava to forecast volcanic eruptions

Peer-Reviewed Publication

UNIVERSITY OF QUEENSLAND

Eruption from above 

IMAGE: THE ERUPTION COVERED MORE THAN 12 SQUARE KILOMETRES WITH 159 CUBIC METRES OF LAVA DESTROYING AROUND 1,600 HOMES. view more 

CREDIT: IGME (INSTITUTO GEOLOGICO Y MINERO DE ESPANA)



University of Queensland researchers have optimised a new technique to help forecast how volcanoes will behave, which could save lives and property around the world.

Dr Teresa Ubide from UQ’s School of the Environment and a team of international collaborators have trialled a new application of the tongue-twisting approach: laser ablation inductively coupled plasma quadruple mass spectrometry.

“It’s a mouthful, but this high-resolution technique offers clearer data on what’s chemically occurring within a volcano’s magma, which is fundamental to forecasting eruption patterns and changes,” Dr Ubide said.

She described magma as the ‘computer code’ of volcanoes, providing information on the eruption style and lava flow.  

“The chemical changes that occur within the liquid portion of the magma during a volcanic eruption are quite incredible,” Dr Ubide said.

“The magma is made up of liquid melt, gas and crystals that combine inside the volcano.

“There are often so many meddling crystals that the magma looks like rocky road, and it’s difficult to observe its chemistry.

“To get these crystals out of the way, we blast the cooled melt – which is known as the rock matrix – with a laser like those used for eye surgery.

“Then we analyse the material measuring its chemical make-up.”

Dr Ubide and the team tested the method on samples collected during the spectacular but damaging 2021 eruption on the Canary Island of La Palma, which lasted 85 days.

“The eruption covered more than 12 square kilometres with 159 cubic metres of lava destroying around 1,600 homes and forcing the evacuation of more than 7,000 people – it cost the country the equivalent of around $1.4 billion,” Dr Ubide said.

“To understand how volcanic eruptions may evolve and to provide warnings and advice to people, live monitoring data is critical.

“Earthquakes, ground changes and gas data provide indirect information on what is happening inside an active volcano but the chemistry of the melt is a direct measure of the ‘personality’ of the magma, its behaviour upon eruption and potential impact on populations and infrastructure.

“The information we gathered during this eruption could help inform volcano monitoring and hazard management in the future.”

The team is now trialling a similar technique on volcanic ash, which can be sampled more readily during a volcanic event.

“We are excited to collaborate with volcano observatories to implement the method as a monitoring tool,” Dr Ubide said.

The research is published in Science Advances. 

The main cone of the La Palma Eruption in the Canary Islands in 2021.

CREDIT

JJ Coello-Bravo

Property damage from lava at the La Palma eruption.

CREDIT

R Balcells

Why the day is 24 hours long: Astrophysicists reveal why Earth’s day was a constant 19.5 hours for over a billion years


Result sheds new light on how climate change will affect the length of the day and validity of climate modelling tools

Peer-Reviewed Publication

UNIVERSITY OF TORONTO

Tidal deposit 

IMAGE: MURRAY AND HIS COLLABORATORS RELIED ON GEOLOGIC EVIDENCE IN THEIR STUDY, LIKE THESE SAMPLES FROM A TIDAL ESTUARY THAT REVEAL THE CYCLE OF SPRING AND NEAP TIDES. view more 

CREDIT: G.E. WILLIAMS




A team of astrophysicists at the University of Toronto (U of T) has revealed how the slow and steady lengthening of Earth’s day caused by the tidal pull of the moon was halted for over a billion years. 

They show that from approximately two billion years ago until 600 million years ago, an atmospheric tide driven by the sun countered the effect of the moon, keeping Earth’s rotational rate steady and the length of day at a constant 19.5 hours.  

Without this billion-year pause in the slowing of our planet’s rotation, our current 24-hour day would stretch to over 60 hours. 

The study describing the result, ‘Why the day is 24 hours long; the history of Earth’s atmospheric thermal tide, composition, and mean temperature,’ was published today in the journal Science Advances. Drawing on geological evidence and using atmospheric research tools, the scientists show that the tidal stalemate between the sun and moon resulted from the incidental but enormously consequential link between the atmosphere’s temperature and Earth’s rotational rate.    

The paper’s authors include Norman Murray, a theoretical astrophysicist with U of T's Canadian Institute for Theoretical Astrophysics (CITA); graduate student Hanbo Wu, CITA and Department of Physics, U of T; Kristen Menou, David A. Dunlap Department of Astronomy & Astrophysics and Department of Physical & Environmental Sciences, University of Toronto Scarborough; Jeremy Laconte, Laboratoire d’astrophysique de Bordeaux and and a former CITA postdoctoral fellow; and Christopher Lee, Department of Physics, U of T. 

When the moon first formed some 4.5 billion years ago, the day was less than 10 hours long. But since then, the moon’s gravitational pull on the Earth has been slowing our planet’s rotation, resulting in an increasingly longer day. Today, it continues to lengthen at a rate of some 1.7 milliseconds every century.  

The moon slows the planet’s rotation by pulling on Earth’s oceans, creating tidal bulges on opposite sides of the planet that we experience as high and low tides. The gravitational pull of the moon on those bulges, plus the friction between the tides and the ocean floor, acts like a brake on our spinning planet. 

“Sunlight also produces an atmospheric tide with the same type of bulges,” says Murray. “The sun's gravity pulls on these atmospheric bulges, producing a torque on the Earth. But instead of slowing down Earth’s rotation like the moon, it speeds it up.” 

For most of Earth’s geological history, the lunar tides have overpowered the solar tides by about a factor of ten; hence, the Earth’s slowing rotational speed and lengthening days.  

But some two billion years ago, the atmospheric bulges were larger because the atmosphere was warmer and because its natural resonance — the frequency at which waves move through it — matched the length of day.  

The atmosphere, like a bell, resonates at a frequency determined by various factors, including temperature. In other words, waves — like those generated by the enormous eruption of the volcano Krakatoa in Indonesia in 1883 — travel through it at a velocity determined by its temperature. The same principle explains why a bell always produces the same note if its temperature is constant. 

Throughout most of Earth’s history that atmospheric resonance has been out of sync with the planet’s rotational rate. Today, each of the two atmospheric “high tides” take 22.8 hours to travel around the world; because that resonance and Earth’s 24-hour rotational period are out of sync, the atmospheric tide is relatively small.  

But during the billion-year period under study, the atmosphere was warmer and resonated with a period of about 10 hours. Also, at the advent of that epoch, Earth’s rotation, slowed by the moon, reached 20 hours. 

When the atmospheric resonance and length of day became even factors — ten and 20 — the atmospheric tide was reinforced, the bulges became larger and the sun’s tidal pull became strong enough to counter the lunar tide.  

“It’s like pushing a child on a swing,” says Murray. “If your push and the period of the swing are out of sync, it’s not going to go very high. But, if they’re in sync and you’re pushing just as the swing stops at one end of its travel, the push will add to the momentum of the swing and it will go further and higher. That’s what happened with the atmospheric resonance and tide.” 

Along with geological evidence, Murray and his colleagues achieved their result using global atmospheric circulation models (GCMs) to predict the atmosphere’s temperature during this period. The GCMs are the same models used by climatologists to study global warming. According to Murray, the fact they worked so well in the team’s research is a timely lesson. 

“I've talked to people who are climate change skeptics who don't believe in the global circulation models that are telling us we’re in a climate crisis,” says Murray. “And I tell them: We used these global circulation models in our research, and they got it right. They work.” 

Despite its remoteness in geological history, the result adds additional perspective to the climate crisis. Because the atmospheric resonance changes with temperature, Murray points out that our current warming atmosphere could have consequences in this tidal imbalance.  

“As we increase Earth's temperature with global warming, we’re also making the resonant frequency move higher — we’re moving our atmosphere farther away from resonance. As a result, there's less torque from the sun and therefore, the length the day is going to get longer, sooner than it would otherwise.” 

-30-

A power spectrum of the Earth's atmosphere. The x-axis is wavelength, e.g. 5 is a wavelength of one fifth of the circumference of the Earth for a wave traveling west to east, and -5 means the same, but for waves traveling east to west. The y-axis is frequency, in cycles per day, e.g. 2 means two cycles per day, or 12 hours. The thin horizontal brown lines show the Solar forcing at one, two, three, etc. cycles per day (24 hours, 12 hours, 8 hours period, and so forth).

CREDIT

Sakazaki & Hamilton