Hubble Spots a Galaxy Hidden in a Dark Cloud - UNIVERSE

This Hubble image features the spiral galaxy IC 4633. ESA/Hubble & NASA, J. Dalcanton, Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA; Acknowledgement: L. Shatz

The subject of this image taken with the NASA/ESA Hubble Space Telescope is the spiral galaxy IC 4633, located 100 million light-years away from us in the constellation Apus. IC 4633 is a galaxy rich in star-forming activity and also hosts an active galactic nucleus at its core. From our point of view, the galaxy is tilted mostly towards us, giving astronomers a fairly good view of its billions of stars.

However, we can’t fully appreciate the features of this galaxy — at least in visible light — because it’s partially concealed by a stretch of dark dust (lower-right third of the image). This dark nebula is part of the Chamaeleon star-forming region, itself located only around 500 light-years from us, in a nearby part of our Milky Way galaxy. The dark clouds in the Chamaeleon region occupy a large area of the southern sky, covering their namesake constellation but also encroaching on nearby constellations, like Apus. The cloud is well-studied for its treasury of young stars, particularly the cloud Cha I, which both Hubble and the NASA/ESA/CSA James Webb Space Telescope have imaged.

The cloud overlapping IC 4633 lies east of the well-known Cha I, II, and III, and is also known as MW9 and the South Celestial Serpent. Classified as an integrated flux nebula (IFN) — a cloud of gas and dust in the Milky Way galaxy that’s not near to any single star and is only faintly lit by the total light of all the galaxy’s stars — this vast, narrow trail of faint gas that snakes over the southern celestial pole is much more subdued looking than its neighbors. Hubble has no problem making out the South Celestial Serpent, though this image captures only a tiny part of it.

Text credit: European Space Agency (ESA)

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Source: Hubble Spots a Galaxy Hidden in a Dark Cloud (nasa.gov) 

Physical activity reduces stress-related brain activity to lower cardiovascular disease risk

New research indicates that physical activity lowers cardiovascular disease risk in part by reducing stress-related signaling in the brain.

In the study, which was led by investigators at Massachusetts General Hospital (MGH), a founding member of the Mass General Brigham healthcare system, and published in the Journal of the American College of Cardiology, people with stress-related conditions such as depression experienced the most cardiovascular benefits from physical activity.

To assess the mechanisms underlying the psychological and cardiovascular disease benefits of physical activity, Ahmed Tawakol, MD, an investigator and cardiologist in the Cardiovascular Imaging Research Center at Massachusetts General Hospital, and his colleagues analyzed medical records and other information of 50,359 participants from the Mass General Brigham Biobank who completed a physical activity survey.

A subset of 774 participants also underwent brain imaging tests and measurements of stress-related brain activity.

Over a median follow-up of 10 years, 12.9% of participants developed cardiovascular disease. Participants who met physical activity recommendations had a 23% lower risk of developing cardiovascular disease compared with those not meeting these recommendations.

Individuals with higher levels of physical activity also tended to have lower stress-related brain activity. Notably, reductions in stress-associated brain activity were driven by gains in function in the prefrontal cortex, a part of the brain involved in executive function (i.e., decision making, impulse control) and is known to restrain stress centers of the brain. Analyses accounted for other lifestyle variables and risk factors for coronary disease.

Moreover, reductions in stress-related brain signaling partially accounted for physical activity’s cardiovascular benefit.

As an extension of this finding, the researchers found in a cohort of 50,359 participants that the cardiovascular benefit of exercise was substantially greater among participants who would be expected to have higher stress-related brain activity, such as those with pre-existing depression.

“Physical activity was roughly twice as effective in lowering cardiovascular disease risk among those with depression. Effects on the brain’s stress-related activity may explain this novel observation,” says Tawakol, who is the senior author of the study.

“Prospective studies are needed to identify potential mediators and to prove causality. In the meantime, clinicians could convey to patients that physical activity may have important brain effects, which may impart greater cardiovascular benefits among individuals with stress-related syndromes such as depression.”

Source: https://www.massgeneral.org/news/press-release/physical-activity-reduces-stress-cvd-risk

Journal article: https://www.jacc.org/doi/10.1016/j.jacc.2024.02.029

Photo via FreePik  

Source: Physical activity reduces stress-related brain activity to lower cardiovascular disease risk – Scents of Science (myfusimotors.com)