Artist’s illustration of a pulsar. Credit: Carl Knox, OzGrav-Swinburne University

Occasionally pulsars—rapidly-spinning remnants of stars that flash like a lighthouse—show extreme variations in brightness. Astrophysicists predict that these short bursts of brightness occur because dense regions of interstellar plasma (the hot gas between stars) scatter the radio waves emitted by the pulsar. However, we still don’t know where the energy sources required to form and sustain these dense plasma regions come from. To better understand these interstellar formations, more detailed observations of their small-scale structure are required. A promising avenue for this is in the scintillation, or “twinkling,” of pulsars.

When a pulsar’s radio waves are scattered by the interstellar plasma, the separate waves interfere and create an interference pattern on the Earth. As the Earth, pulsar, and plasma move relative to each other, this pattern is observed as brightness variations in time and in frequency: the dynamic spectrum. This is scintillation, or “twinkling.” The scattering and twinkling occurs in small regions of the plasma thanks to the point-like nature of pulsar signals. Following specialized signal processing of the dynamic spectrum, we can observe vivid parabolic features known as scintillation arcs that are related to the image of the pulsar’s scattered radiation on the sky.


One particular pulsar, called J1603-7202, underwent extreme scattering in 2006. This makes it an exciting target for examining these dense plasma regions. However, the pulsar’s trajectory still hasn’t been determined as it orbits another compact star called a white dwarf in a face-on orbit, and astronomers don’t have alternative methods to measure it in this situation. Fortunately, scintillation arcs serve a double purpose: their curvatures are related to the pulsar’s velocity, as well as the distance to the pulsar and the plasma. How the pulsar’s velocity changes as it orbits depends on the orbit’s orientation in space. Therefore, in the case of pulsar J1603-7202, we calculated the changes in the curvature of the arcs over time to determine the orientation.

The measurements we obtained for the orbit of pulsar J1603-7202 are a significant improvement compared to previous analyses. This demonstrates the viability of scintillation in supplementing alternative methods. We measured the distance to the plasma and showed that it was about three-quarters of the distance to the pulsar, from Earth. This does not seem to coincide with the positions of any known stars or interstellar gas clouds. Pulsar scintillation studies often explore structures such as this, which are otherwise invisible. The question, therefore, remains open: what is the source of the plasma that scatters the pulsar’s radiation?

Finally, using our orbit measurement, we are able to estimate the mass of J1603-7202’s orbital companion. It was calculated to be about half the mass of the Sun. When considered alongside the highly circular orbit of J160-7202, this implies the companion is likely a stellar remnant composed of carbon and oxygen — a rarer find around a pulsar than the more common helium-based remnants.


As we now possess a near-complete model of the orbit, it’s currently possible to transform scintillation observations of J1603-7202 into on-sky scattered images and map the interstellar plasma at Solar System scales. Creating images of the physical structures that cause extreme scattering of radio waves may give us a better understanding of how such dense regions form and of the role the interstellar plasma plays in the evolution of galaxies.

Written by PhD student Kris Walker (ICRAR-UWA) and Dr. Daniel Reardon (OzGrav-Swinburne University).

Reference: “Orbital Dynamics and Extreme Scattering Event Properties from Long-term Scintillation Observations of PSR J1603−7202” by Kris Walker, Daniel J. Reardon, Eric Thrane and Rory Smith, 28 June 2022, The Astrophysical Journal.
DOI: 10.3847/1538-4357/ac69c6

The most common kind of heart disease in the US is coronary artery disease (CAD), which can result in a heart attack.

Discriminatory housing policies from the past may still have an impact on heart disease risk factors and outcomes today.

More than 60 years after they were outlawed, the historical discriminatory housing practices known as “redlining” are still connected to heart disease and related risk factors in the affected districts, according to a study recently published in the Journal of the American College of Cardiology. Health disparities have been related to a number of socioeconomic, environmental, and social variables. This research adds to the increasing body of evidence demonstrating the long-term cardiovascular impacts disparities may have on vulnerable groups.

The phrase “redlining” is used to refer to a variety of discriminatory housing practices. Its roots are in a government program from the 1930s when the Home Owners’ Loan Corporation produced maps of over 200 American towns with ratings based on racial/ethnic mix, housing conditions, and local surroundings.


The graded locations were color-coded as A (“best” or green), B (“still desirable” or blue), C (“definitely declining” or yellow), and D (“hazardous” or red) depending on the potential lending risk. The areas with a D-rating were referred to as “redlined” areas. Despite the fact that these housing practices were prohibited in the 1960s, throughout the course of the last century, their consequences and other forms of discrimination have persisted to shape social and environmental structures, worsening health inequities.

“We already know historic redlining has been linked with modern-day health inequities in major urban areas, including asthma, certain types of cancer, preterm birth, mental health, and other chronic diseases,” said Sadeer Al-Kindi, MD, a cardiologist at University Hospitals Harrington Heart & Vascular Institute and Assistant Professor of Medicine at Case Western Reserve University in Cleveland and a senior author on the study. “While ours is the first study to examine the national relationship between redlined neighborhoods and cardiovascular diseases, it’s logical that many of the socioeconomic, environmental, and social impacts of redlining on other areas of residents’ health outcomes would also be seen in heart disease.”

A previous study demonstrated that Black adults living in historically redlined areas had a lower cardiovascular health score than Black adults living in A-graded neighborhoods. The current study supports this finding and extends the demonstrated health inequality nationally, showing that redlining not only affects coronary artery disease, stroke, and chronic kidney disease but also is associated with an increased risk of comorbidities and a lack of access to appropriate medical care.


The researchers used original Home Owners’ Loan Corporation (HOLC) graded data and calculated the percentage of intersection between each graded neighborhood boundary and the 2020 U.S. Census tract boundaries. They excluded any census tracts with less than 20% total area of intersection. The researchers used the graded intersections to generate a scale using their corresponding HOLC numeric scores (1-4 corresponding to A-D) and created a score that was transformed back into one of four categories: A (1), B (2), C (3) and D (4). The study defined redlined neighborhoods as D-graded census tracts and non-redlined neighborhoods as A- through C-graded census tracts.

The CDC PLACES database, which reports the prevalence estimates of census tract level health indicators, as well as census-tract level exposure of particulate matter and Diesel particulate matter from the Environmental Protection Agency’s 2021 environmental justice tool, were used to calculate potential environmental confounders. Other outcome variables and assessments used included: markers of health care access, cardiometabolic risk factors, and cardiometabolic outcomes. The researchers then linked HOLC-graded census tracts with the prevalence of cardiometabolic indicators and calculated the average of each indicator across census tracts in each HOLC grade.

More than 11,000 HOLC-graded census tracts were included, comprising over 38.5 million inhabitants. The A-graded areas covered 7.1%, B-graded areas covered 19.4%, C-graded areas covered 42% and D-graded areas covered 31.5% of census tracts. The percentage of Black and Hispanic residents increased across HOLC grades (A-D, respectively). Across HOLC grades A through D, the researchers found statistically significant increases in the prevalence of coronary artery disease, stroke, and chronic kidney disease.

“We found neighborhoods with so-called better HOLC grades had higher cholesterol screening and routine health visits when compared to neighborhoods with worse HOLC grades. And the prevalence of adults 18 to 64 years old without health insurance nearly doubled from A through D-graded areas,” said Issam Motairek, MD, lead author of the study and a clinical research associate at University Hospitals Harrington Heart & Vascular Institute in Cleveland. “In each stepwise increase across the HOLC grading spectrum, from A to D, we also observed an overall increase in rates of diabetes, obesity, hypertension, and smoking.”


According to the researchers, the association between redlining and the prevalence of cardiometabolic conditions further illustrates that historic redlining practices may impact contemporary cardiovascular outcomes by traditional and non-traditional risk factors. Residents of redlined neighborhoods, particularly minorities, are known to have lower access to public transportation, health care insurance, and healthy food choices, which increases their risk for missed prevention and adverse health outcomes.

Disparities in environmental exposures and in socioeconomic attributes may help explain the poor health outcomes in redlined neighborhoods, which are often situated next to major sources of pollution and make residents more likely to experience the detrimental health effects of disproportionately higher exposure to air pollution, less green space and other environmental toxins. Residents of redlined neighborhoods also experience financial strain, dismantled communities, and racial discrimination which may lead to increased stress and associated adverse health events.

Study limitations include self-reported health outcomes in the CDC PLACES database, which may be mischaracterized. The study was also unable to measure confounders such as behavioral and genetic factors. The definition of redlining census tract boundaries has also not been standardized across studies.

Reference: “Historical Neighborhood Redlining and Contemporary Cardiometabolic Risk” by Issam Motairek, Eun Kyung Lee, Scott Janus, Michael Farkouh, Darcy Freedman, Jackson Wright, Khurram Nasir, Sanjay Rajagopalan and Sadeer Al-Kindi, 4 July 2022, Journal of the American College of Cardiology.
DOI: 10.1016/j.jacc.2022.05.010

You may have heard of MCT oil, a relatively new supplement that takes the form of a colorless oil. MCT oil isn’t just a passing health trend, but a proven benefit to brain and gut health. MCT stands for medium-chain triglycerides, which are one of the easiest types of fat to digest and break down for fuel. Besides fueling the body and brain, there are several other benefits of MCTs to know about, as well as potential side effects.

What Are Medium-Chain Triglycerides?

When you think of triglycerides, you probably think of high cholesterol and heart disease. But triglycerides are a type of fat — in fact, they’re the most abundant type of fat found in your body. There are short-, medium-, and long-chain triglycerides, and your body uses all of them for fuel.

Medium-Chain Triglycerides (MCTs) are a tasteless oil isolated and extracted from coconuts and palm kernels. There are four types of MCTs, known as C6, C8, C10, and C12. These represent the various fatty acids containing a medium-length carbon chain of 6 to 12 atoms. You can take MCT oil daily, but you may experience side effects when you start taking it.

Benefits of Medium-Chain Triglycerides

Research suggests that MCTs can improve mental clarity, help with weight management, lower cholesterol levels, and protect brain health.

Boosts Mental Clarity

MCTs penetrate the blood-brain barrier, which controls the molecules let into the brain. Since they don’t need to be broken down, MCTs provide an instant source of energy for your brain that is healthier than glucose. In fact, MCTs don’t have the same “brain fog” effect that often follows eating sugary foods. If you’re trying to avoid simple carbohydrates, MCTs can keep your brain and body running while preventing sugar cravings.

Protects Brain Health

The brain’s ability to derive energy from glucose declines with age, leading to neurodegeneration and cognitive decline. MCT oil can protect your memory and cognitive function as you age. It provides all the energy brain cells require, and research suggests it can improve cognitive performance at any age.^[1]

Reduces Your Heart Disease Risk and Promotes Fat Burning

Like many healthy fats, MCTs are good for your heart. They’re shown to have powerful anti-inflammatory properties and improve fat metabolism.^[2]

Research shows supplementing with MCT oil daily can melt 1.1 pounds every three weeks.^[3] MCTs increase fat oxidation, which means you burn more calories at the same time. MCTs also induce thermogenesis, which causes you to expend more energy to release body heat.

MCT Oil Side Effects and Dosage

MCTs can cause side effects, including flatulence, diarrhea, stomach pain, and bloating. If you haven’t taken MCT oil before, start with no more with a teaspoon in a day. Build up to no more than three or four teaspoons per day. If you experience any gastrointestinal problems like cramping or nausea, reduce your dose.

How Do You Take MCT Oil?

It’s easy to add MCT oil to your routine by putting it in your morning coffee, smoothie, cereal, yogurt, or oatmeal. You can even take it by itself. MCT oil is tasteless but has an oily consistency.

MCT Oil Summary

You can find MCT oil at health food shops. The only ingredient listed for an MCT oil product should be 100% medium-chain triglycerides. Some MCT supplements list the types of MCTs in the ingredients, such as C8 or C12. According to research, C6, C8, and C10 offer the most benefits.^[4] Keep in mind that MCT oil is a source of calories and not a magic pill for weight loss. You still need to exercise and burn more calories than you expend to lose weight.

References:

1. “The effects of medium chain triglyceride (MCT) supplementation using a C₈:C₁₀ ratio of 30:70 on cognitive performance in healthy young adults” by Jake S. Ashton, James W. Roberts, Caroline J. Wakefield, Richard M. Page, Don P.M. MacLaren, Simon Marwood and James J. Malone, 18 November 2020, Physiology & Behavior.
   DOI: 10.1016/j.physbeh.2020.113252
2. “Medium Chain Triglyceride (MCT) Oil Affects the Immunophenotype via Reprogramming of Mitochondrial Respiration in Murine Macrophages” by Seungmin Yu, Gwang-woong Go and Wooki Kim, 5 November 2019, Foods.
   DOI: 10.3390/foods8110553
3. “Effects of Medium-Chain Triglycerides on Weight Loss and Body Composition: A Meta-Analysis of Randomized Controlled Trials” by Karen Mumme, PGDipSc and Welma Stonehouse, PhD, 1 February 2015, Journal of the Academy of Nutrition and Dietetics.
   DOI: 10.1016/j.jand.2014.10.022
4. “Medium-Chain Triglycerides and Health” by Volpe, Stella Lucia Ph.D., RDN, FACSM, ACSM-CEP, 2020, ACSM’s Health & Fitness Journal.
   DOI: 10.1249/FIT.0000000000000537

1992 – 2022

Global mean sea level has risen 101 millimeters (3.98 inches) since 1992, and it continues to do so at 3.9 mm (0.15 inches) per year.

A new satellite was launched by scientists and engineers thirty years ago to examine how the waters rise and decrease over time, a job that was previously only possible from the coast. On August 10, 1992, TOPEX/Poseidon launched into orbit and began a 30-year record of ocean surface height all across the globe. The findings have verified what scientists had previously seen from the shorelines: the seas are rising, and the rate is accelerating.


Researchers have found that global mean sea level—shown in the line plot above and below—has risen 10.1 centimeters (3.98 inches) since 1992. Over the past 140 years, satellites and tide gauges together show that global sea level has risen 21 to 24 centimeters (8 to 9 inches).

Beginning with TOPEX/Poseidon, NASA and partner space agencies have flown a continuous series of satellites that use radar altimeters to monitor ocean surface topography. Essentially, the satellites monitor the vertical shape and height of the ocean. Radar altimeters continually emit pulses of radio waves (microwaves), which are reflected back toward the satellite by the ocean’s surface. The instruments calculate the time it takes for the signal to return, while also tracking the precise location of the satellite in space. From this, scientists can calculate the height of the sea surface directly underneath the satellite.

Since 1992, five missions with similar altimeters have repeated the same orbit every 10 days: TOPEX/Poseidon (1992 to 2006), Jason-1 (2001 to 2013), the Ocean Surface Topography Mission/Jason-2 (2008 to 2019), Jason-3 (2016 to present), and Sentinel-6 Michael Freilich (2020 to present). The missions were built through various partnerships between NASA, France’s Centre National d’Etudes Spatiales (CNES), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the European Space Agency (ESA), and the U.S. National Oceanic and Atmospheric Administration (NOAA).


Combined, the mission teams have assembled a unified, standardized ocean topography record that is equivalent to the work of a half-million tide gauges. The researchers accumulated and corroborated a data record that is now long enough and sensitive enough to detect global and regional sea level changes beyond the seasonal, yearly, and decadal cycles that naturally occur.

“With 30 years of data, we can finally see what a huge impact we have on the Earth’s climate,” said Josh Willis, an oceanographer at the Jet Propulsion Laboratory (JPL) and NASA’s project scientist for Sentinel-6 Michael Freilich. “The rise of sea level caused by human interference with the climate now dwarfs the natural cycles. And it is happening faster and faster every decade.”

The map at the top of this page shows global trends in sea level as observed from 1993 to 2022 by TOPEX/Poseidon, the three Jason missions, and Sentinel-6 Michael Freilich. Note the spatial variations in the rate of sea level rise, with some parts of the ocean rising faster (depicted in red and deep orange) than the global rate. Many of the anomalies reflect long-term shifts in ocean currents and heat distribution.

1992 – 2022

The altimetry data also show that the rate of sea level rise is accelerating. Over the course of the 20th century, global mean sea level rose at about 1.5 millimeters (0.06 inches) per year. By the early 1990s, it was about 2.5 mm (0.1 inches) per year. Over the past decade, the rate has increased to 3.9 mm (0.15 inches) per year.

In the line plot, the highs and lows each year are caused by the exchange of water between the land and sea. “Winter rain and snowfall in the northern hemisphere shifts water from ocean to land, and it takes some time for this to runoff back into the oceans,” Willis noted. “This effect usually causes about 1 centimeter of rise and fall each year, with a bit more or less during El Niño and La Niña years. It’s literally like the heartbeat of the planet.”

While a few millimeters of sea level rise per year may seem small, scientists estimate that every 2.5 centimeters (1 inch) of sea level rise translates into 2.5 meters (8.5 feet) of beachfront lost along the average coast. It also means that high tides and storm surges can rise even higher, bringing more coastal flooding, even on sunny days. In a report issued in February 2022, U.S. scientists concluded that by 2050 sea level along U.S. coastlines could rise between 25 to 30 centimeters (10 to 12 inches) above today’s levels.

“What stands out from the satellite altimetry record is that the rise over 30 years is about ten times bigger than the natural exchange of water between ocean and land in a year,” Willis said. “In other words, the human-caused rise in global sea level is now ten times bigger than the natural cycles.”

NASA Earth Observatory video and image by Joshua Stevens, using TOPEX/Poseidon data courtesy of Josh Willis/JPL-Caltech.

High-Intensity-Interval-Training increases fat burning more than aerobic exercise. In fact, a few sessions of HIIT per week will turn your body into a fat-burning “machine.”

High-Intensity Interval Training Can Help Burn More Fat

“If that stubborn body fat isn’t going away, consider adding High-Intensity-Interval-Training or HIIT to your exercise routine,” says Professor Zeljko Pedisic.

HIIT increases fat burning more than aerobic exercise, finds a study that was recently published in the British Journal of Sports Medicine.

How was the study conducted?

For the study, researchers pooled results from 18 controlled intervention trials on the effects of HIIT on the rate of fat burning during exercise.

The intervention trials included a total of 511 adult participants who were engaged in either supervised HIIT, moderate-intensity aerobic exercise, or a non-exercising control group.

The duration of exercise interventions ranged from 2 to 14 weeks. In almost all of the studies, participants engaged in three HIIT sessions per week.

What are the key findings?

According to the research, a few sessions of HIIT per week will turn your body into a fat-burning “machine.” HIIT will make you start burning more fat not just during the HIIT sessions, but also during other types of physical activity, such as brisk walking, swimming, and playing sports.

Fat metabolism will improve after only four weeks of HIIT, and it will continue to improve over time.

After 12 weeks of HIIT, each minute of physical activity can be expected to burn an additional 0.13 grams of fat. For someone who engages in 150 minutes of physical activity per week, this could lead to around 10 kg (22 pounds) of additional fat burned in a decade.

According to the findings, overweight individuals may expect greater increases in fat burning, compared with “normal”-weight individuals.


While people could also improve their fat metabolism by engaging in aerobic exercise (e.g. jogging), this would require a much higher time commitment, and the improvements would be smaller.

Why is this important?

These findings may help more than two billion overweight people in the world to improve their fat metabolism and reduce weight.

They may also help billions of others to prevent unwanted weight gain over time.

Picture your 10-year older self with additional 22 pounds of body fat: HIIT may help you avoid such a change in the body composition.

“According to the recent Worldwide Survey of Fitness Trends, HIIT is among the most popular types of workouts. If you are not already doing it, maybe you should give it a go,” concludes Professor Pedisic.


Reference: “Effects of high-intensity interval training (HIIT) and sprint interval training (SIT) on fat oxidation during exercise: a systematic review and meta-analysis” by Muhammed M Atakan, Yasemin Guzel, Nipun Shrestha, Sukran N Kosar, Jozo Grgic, Todd A Astorino, Huseyin H Turnagol and Zeljko Pedisic, 20 July 2022, British Journal of Sports Medicine.
DOI: 10.1136/bjsports-2021-105181