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Human bodies are sacks of fluids supported by skeletons. The entire human organism has evolved over billions of years on Earth in harmony with the planet’s specific gravity. But when astronauts spend too much time on the ISS in a microgravity environment, the organism responds, the fluids shift, and problems can occur.

One of those problems is with vision, and scientists are working to understand how it happens and what they can do about it.

We’re talking about Spaceflight-Associated Neuro-Ocular Syndrome (SANS). NASA says that 70% of astronauts who spend time on the International Space Station (ISS) experience at least mild SANS. Sometimes, the effect is minor and often temporary. Other times, it’s more severe and can cause long-term vision problems, including partial loss of vision.

Researchers have been dealing with microgravity and its effects on vision for a while. “Spaceflight Associated Neuro-ocular Syndrome (SANS), previously known as Visual Impairment Intracranial Pressure (VIIP), is a major risk associated with long-duration spaceflight,” wrote the authors of a 2020 paper. “During prolonged missions, optic disk edema, posterior globe flattening, decreased near vision, and hyperopic shifts are hallmarks of SANS. This risk stems from the lack of gravity, which causes a headward shift of blood and other body fluids.”

Now, a group of physicians are working with Polaris Dawn to understand the problem.

Polaris Dawn is a private spaceflight initiative operated by SpaceX. It will send four private astronauts on a highly elliptical Earth orbit that will take them 1,400 kilometres (870 mi) away from Earth. This is the furthest any human being has been from Earth since the Apollo missions.

Matt Lyon, MD, from the Medical College of Georgia (MCG) at Augusta University, is leading a team that is working with Polaris Dawn to study SANS.

“The changes start happening on day one,” said Lyon, who also is the J. Harold Harrison M.D. Distinguished Chair in Telehealth. “We are not entirely sure what causes these issues with vision, but we suspect it has to do with a shift in cerebrospinal fluid in the optic nerve sheath. On Earth, gravity pushes that fluid down and it drains out, but in space, it floats up and presses against the optic nerve and retina.”

Lyon and his colleagues are focusing on the optic nerve sheath. The optic nerve is a conduit that carries visual information from the eyes to the brain. Inside the sheath, the nerve is protected by cerebrospinal fluid. The cerebrospinal fluid (CSF) carries toxins away from the eye.

A simple schematic of the optic nerve and the sheath with cerebrospinal fluid. Image Credit: Netteland et al. 2023.

Here on Earth, MCG patented the use of ultrasound to image the optic nerve and its sheath and rapidly visualize damage associated with pressure and fluid changes in the sheath. Now, Lyon and his team are putting a portable ultrasound machine in the hands of the four Polaris Dawn astronauts and training them on how to use it.

But first they’re screening the four astronauts to try to determine which people are more susceptible to SANS. They think that people who suffered concussions or mild traumatic brain injuries (TBIs) in the past are likely more susceptible to SANS.

“We discovered that when the cerebral spinal pressure goes up with mild traumatic brain injuries (TBIs), there is resulting damage to the sheath that is likely lifelong,” he explained. “We think that when astronauts who have experienced concussions or mild TBIs go into space and experience the low-gravity fluid shifts, the sheath dilates from the increase in volume. It is like a tire — a normal tire remains its normal shape as it is filled with air, and the shape doesn’t change. When it’s damaged, like bulges on the side of a tire, the fluid fills the bulges up and the sheath expands. This can cause pressure on the nerve and retina. A damaged sheath is less of a problem on Earth, but in space, the excess fluid has nowhere to go.”

It’s critical that the private Polaris Dawn astronauts image the changes to their optical nerves and sheaths in real-time. Real-time data will help researchers understand if vision changes due to SANS are caused by the sheer volume of fluid, the increased pressure from the fluid, or interactions between the two.

The video below shows how ultrasound is used to scan the eye, including the optical nerve (0:40).

Go to the 0:40 second mark to see the eye being scanned.

“If it’s just volume, we suspect the cerebrospinal fluid goes up, fills this floppy bag and gets stuck. It’s almost like not flushing your toilets. You’re creating this toxic environment, because the cerebral spinal fluid (CSF) is what carries toxins away from your eyes and nerves, and instead the toxins sit against the optic nerve, killing it,” Lyon said. “But it could be that combined with the increased pressure that comes with increased CSF, which would be like getting intermittent hypertension in your eye.”

The solution to SANS could be a Lower Body Negative Pressure (LBNP) device. These are large, bulky devices that counteract the headward shift of fluids in microgravity by creating ground reaction forces (GRFs). They’re typically airtight chambers that astronauts spend time in. Unfortunately, LBNPs require astronauts to be static while using them. NASA tested them during the International Microgravity Laboratory on Space Shuttle Mission STS-65.

This image showed payload commander Richard Hieb wearing and testing the LBNP on Shuttle mission STS 65 in 1994. By creating lower pressure in the bottom of the body, blood and fluids are prevented from accumulating in the upper body in microgravity. Image Credit: NASA.

Researchers at the University of California’s Department of Orthopaedic Surgery and Department of Bioengineering are developing a mobile version of an LBNP.

“Our new mobile gravity suit is relatively small, untethered, and flexible in order to improve mobility in space. We hypothesized that this novel mobile gravity suit generates greater ground reaction forces than a standard LBNP chamber,” wrote the authors of the 2020 paper.

This image shows a mobile LBNP suit under development. Image Credit: Ashari and Hargens, 2020.

Mobile Lower Body Negative Pressure suits are still under development, and scientists need more data. Polaris Dawn can help provide the needed data.

The ultrasound images of the optical nerve are part of a broader research effort that will be conducted during Polaris Dawn. The Medical College of Georgia is one of 23 institutions that the mission is working with. The data that Polaris Dawn returns should help lead to a solution for SANS.

The post How Can Astronauts Avoid Vision Loss from Spaceflight? appeared first on Universe Today.

Promising new vaccines are designed to be given to patients at risk of developing Alzheimer's disease. If they perform well in clinical trials, they have the potential to one day rid society of dementia

Scientists have observed new details of how plasma interacts with magnetic fields, potentially providing insight into the formation of enormous plasma jets that stretch between the stars.

Scientists have observed new details of how plasma interacts with magnetic fields, potentially providing insight into the formation of enormous plasma jets that stretch between the stars.

Astronomers have achieved the highest resolution ever obtained from the surface of Earth. They managed this feat by detecting light from distant galaxies at a frequency of around 345 GHz, equivalent to a wavelength of 0.87 mm. They estimate that in future they will be able to make black hole images that are 50% more detailed than was possible before, bringing the region immediately outside the boundary of nearby supermassive black holes into sharper focus. They will also be able to image more black holes than they have done so far. The new detections are part of a pilot experiment.

A new variant of mpox is surging in Central Africa, raising concerns about how quickly it could spread further afield

Micro- and nanoplastics are in our food, water and the air we breathe. They are showing up in our bodies, too. Now, researchers have developed a low-cost, portable tool to accurately measure plastic released from everyday sources like disposable cups and water bottles.

Electron microscope (EM) has revolutionized our ability to visualize the intricate details inside cells. The advancement to 3D electron microscopy, known as volume EM (vEM), has further expanded this three-dimensional, nanoscale imaging capacity. However, trade-offs between imaging speed, quality, and sample size still limit the achievable imaging area and volume. Concurrently, artificial intelligence (AI) is emerging as a pivotal force across various scientific domains, driving breakthroughs and serving as a vital tool in the scientific process.

A pioneering study titled 'Causal effect of video gaming on mental well-being in Japan 2020-2022,' published in Nature Human Behaviour, has conducted the most comprehensive investigation to date on the causal relationship between video gaming and mental well-being. This research, the first to demonstrate this relationship using real-life data, challenges commonly held views about the effects of gaming.

Lunar igneous activities including intrusive and extrusive magmatism, and their products contain significant information about the lunar interior and its thermal state. Their distribution is asymmetrical on the nearside and farside, reflecting the global lunar dichotomy. In addition to previously returned lunar samples all from nearside (Apollo, Luna, and Chang'e-5), samples from the South Pole-Aitken (SPA) basin on the farside have long been thought to hold the key to rebalancing the asymmetrical understandings of the Moon and disclosing the lunar dichotomy conundrum.

The James Webb Space Telescope has spotted six likely rogue worlds -- objects with planet-like masses but untethered from any star's gravity -- including the lightest ever identified with a dusty disk around it. The elusive objects offer new evidence that the same cosmic processes that give birth to stars may also play a common role in making objects only slightly bigger than Jupiter.

Researchers have developed an artificial intelligence which can differentiate cancer cells from normal cells, as well as detect the very early stages of viral infection inside cells. The findings pave the way for improved diagnostic techniques and new monitoring strategies for disease. The AI can detect rearrangements inside cells as small as 20nm, or 5,000 times smaller than the width of a human hair. These alterations are too small and subtle for human observers to find with traditional methods alone.

While meant to simulate wood bats, regulation USA Baseball metal bats are more forgiving than wood for young players who might not connect with the ball on a bat's optimal 'sweet spot.' After testing wood bats and two types of metal bats with youth players, researchers found that the exit speed of a hit ball was as much as 5% faster with metal bats over wood. Analyzing the data, they found that the performance of the USA Baseball metal bats at the sweet spot was similar to wood. It was when the hits were on less optimal areas that there was a bigger difference: there was more of a penalty with wood bats when the hitters were not on the sweet spot than with the metal bats.

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A proposed artificial intelligence tool to support clinician decision-making about hospital patients at risk for sepsis has an unusual feature: accounting for its lack of certainty and suggesting what demographic data, vital signs and lab test results it needs to improve its predictive performance.

Neuroscientists have sought to better understand brain function but lacked the capability to observe neuronal activity deep within the brain. Scientists have applied rational molecular engineering to develop photoacoustic probes that can be used deep within brain tissue to label and visualize neurons. This imaging approach expands significantly on what neuroscientists have been able to see with conventional light microscopy, offering the potential to report on deep neuron activity and better understand brain function.

A cyberterrorism charge in Pakistan connected to riots in the UK illustrates how authorities are reaching across borders to tackle disinformation, but bringing overseas suspects to justice won't always be possible

https://traffic.libsyn.com/secure/sciencesalon/mss461_Helen_Pluckrose_2024_08_27.mp3 Download MP3

The stated goals of diversity, equity, and inclusion programs are often reasonable, if not noble—to create a more welcoming and inclusive environment for all. Yet, as more and more people are discovering, DEI as commonly practiced isn’t a natural extension of past civil rights movements or an ethical framework for opposing discrimination on the grounds of race, sex, etc. Rather, it is inextricably connected with an illiberal and authoritarian ideology—Critical Social Justice—that demands adherence to its tenets and punishes any dissent from its dogma.

Even the mildest questions about Critical Social Justice claims—that all white people are racists, that all underrepresented minorities are oppressed, that sex and gender differences have no biological basis, that censorship is a necessary good—are regularly met by DEI trainers and HR officers with pat commands: “Educate yourself,” “Do the work,” “Listen and learn.” At work, raises, promotions, and future employment often depend on our nodding approval of such claims. At school, grades, nominations, and awards are often contingent upon our active agreement with these beliefs. In our daily lives, Critical Social Justice ideology poses a genuine threat not only to our fundamental rights but also to the future of our democratic systems, but if we suggest this, we risk being canceled or shunned by community members. When facing a choice between silent submission and risky if ethical opposition, what is a person to do?

While a growing number of groups concerned about the nature of Critical Social Justice have begun to attack it from the top down through legal, financial, and political means, The Counterweight Handbook takes a decidedly different and novel approach. It works from the bottom up and is written to empower individuals who wish to combat Critical Social Justice in their personal and professional lives. Based on the author’s years of experience studying, exposing, and fighting Critical Social Justice ideology and advising individuals and organizations struggling with it, The Counterweight Handbook is designed to help people address Critical Social Justice problems in the most ethical and effective way possible. It not only offers principled responses to the main claims of Critical Social Justice but also teaches individuals what to do when they are asked to affirm beliefs they do not hold, undergo training in an ideology they cannot support, or submit to antiscientific testing and retraining of their “unconscious” minds. In short, it is for all of us who believe in freedom of speech and conscience, who wish to push back against the hostile work and educational environments Critical Social Justice has created, and who want to stand up for our individual liberties and universal rights.

Helen Pluckrose is a liberal political and cultural writer and was one of the founders of Counterweight. A participant in the Grievance Studies Affair probe that highlighted problems in Critical Social Justice scholarship, she is the coauthor of Cynical Theories and Social (In)justice. She lives in England and can be found on X @HPluckrose

Shermer and Pluckrose discuss:

• the problem to be solved?
• origin of the problem: post-modernism and Critical Social Justice ideology
• Diversity, Equity and Inclusion (DEI)
• what it means to “Educate yourself,” “Do the work,” “Listen and learn.”
• top-down (Chris Rufo, Ron DeSantis) vs. bottom-up counter measures
• gender pronoun declarations
• race reckoning
• White supremacy accusations and White guilt
• antiracism
• gender ideology
• Blackness
• Critical Race Theory (CRT)
• decolonize
• discourse
• dismantle
• fragility
• intersectionality
• normativity
• positionality
• privilege
• problematic
• woke.

If you enjoy the podcast, please show your support by making a $5 or $10 monthly donation.

A nasty sort of bias called Malmquist bias affects almost every astronomical survey, and the only solution is to…keep doing surveys.

Back in the 1970’s and 80’s astronomers first began to identify a structure known as the Great Attractor, which is defined by the common motion of all the galaxies in our nearby vicinity of the cosmos.

But for over a decade, however, many astronomers weren’t exactly convinced that the Great Attractor existed. Their skepticism was well justified because of a common observational effect in astronomy known as Malmquist bias. Named after the Swedish astronomer Gunnar Malmquist, who first elucidated a discussion of this effect in 1922, this bias is a specialized version of a much more common statistical effect known as selection bias.

Most astronomical surveys are limited in brightness. There is a certain floor representing the dimmest possible object that a given telescope with a given exposure will be able to see. But objects in the universe can be dim for two separate reasons: because they are well and truly dim intrinsically, or simply because they are far away. So a typical survey of astronomical objects, like galaxies, will preferentially select for closer and/or brighter ones. In the case of galaxies, the farther out we look from the Milky Way, there more likely we’ll only catch the brightest galaxies at that distance, and miss all of their dimmer siblings.

This bias could potentially distort our understanding of the wider universe, especially if we’re trying to use the velocities of galaxies to map out their bulk motion. In those first surveys in the 1970’s and 80’s, many astronomers argued that we were only seeing the movements of the brightest galaxies, giving the illusion of a general flow towards the Great Attractor, and a more complete census of the local universe would average everything out.

The solution? Even more surveys, with more depth and more completeness, which eventually revealed the reality of the Great Attractor.

The post The Hardest Bias in Astronomy appeared first on Universe Today.