Once a week.
Subscribe to our weekly newsletter.
Your genetics influence how resilient you are to the cold
What makes some people more likely to shiver than others?
Some people just aren't bothered by the cold, no matter how low the temperature dips. And the reason for this may be in a person's genes.
Our new research shows that a common genetic variant in the skeletal muscle gene, ACTN3, makes people more resilient to cold temperatures.
Around one in five people lack a muscle protein called alpha-actinin-3 due to a single genetic change in the ACTN3 gene. The absence of alpha-actinin-3 became more common as some modern humans migrated out of Africa and into the colder climates of Europe and Asia. The reasons for this increase have remained unknown until now.
Our recent study, conducted alongside researchers from Lithuania, Sweden and Australia, suggests that if you're alpha-actinin-3 deficient, then your body can maintain a higher core temperature and you shiver less when exposed to cold, compared with those who have alpha-actinin-3.
We looked at 42 men aged 18 to 40 years from Kaunas in southern Lithuania and exposed them to cold water (14℃) for a maximum of 120 minutes, or until their core body temperature reached 35.5℃. We broke their exposure up into 20-minute periods in the cold with ten-minute breaks at room temperature. We then separated participants into two groups based on their ACTN3 genotype (whether or not they had the alpha-actinin-3 protein).
While only 30% of participants with the alpha-actinin-3 protein reached the full 120 minutes of cold exposure, 69% of those that were alpha-actinin-3 deficient completed the full cold-water exposure time. We also assessed the amount of shivering during cold exposure periods, which told us that those without alpha-actinin-3 shiver less than those who have alpha-actinin-3.
Our study suggests that genetic changes caused by the loss of alpha-actinin-3 in our skeletal muscle affect how well we can tolerate cold temperatures, with those that are alpha-actinin-3 deficient better able to maintain their body temperature and conserve their energy by shivering less during cold exposure. However, future research will need to investigate whether similar results would be seen in women.
Skeletal muscles are made up of two types of muscle fibres: fast and slow. Alpha-actinin-3 is predominantly found in fast muscle fibres. These fibres are responsible for the rapid and forceful contractions used during sprinting, but typically fatigue quickly and are prone to injury. Slow muscle fibres on the other hand generate less force but are resistant to fatigue. These are primarily the muscle you'd use during endurance events, like marathon running.
Our previous work has shown that ACTN3 variants play an important role in our muscle's ability to generate strength. We showed that the loss of alpha-actinin-3 is detrimental to sprint performance in athletes and the general population, but may benefit muscle endurance.
This is because the loss of alpha-actinin-3 causes the muscle to behave more like a slower muscle fibre. This means that alpha-actinin-3 deficient muscles are weaker but recover more quickly from fatigue. But while this is detrimental to sprint performance, it may be beneficial during more endurance events. This improvement in endurance muscle capacity could also influence our response to cold.
While alpha-actinin-3 deficiency does not cause muscle disease, it does influence how our muscle functions. Our study shows that ACTN3 is more than just the "gene for speed", but that its loss improves our muscle's ability to generate heat and reduces the need to shiver when exposed to cold. This improvement in muscle function would conserve energy and ultimately increase survival in cold temperatures, which we think is a key reason why we see an increase in alpha-actinin-3 deficient people today, as this would have helped modern humans better tolerate cooler climates as they migrated out of Africa.
The goal of our research is to improve our understanding of how our genetics influence how our muscle works. This will allow us to develop better treatments for those who suffer from muscle diseases, like Duchenne muscular dystrophy, as well as more common conditions, such as obesity and type 2 diabetes. A better understanding of how variants in alpha-actinin-3 influences these conditions will give us better ways to treat and prevent these conditions in the future.
Victoria Wyckelsma, Postdoctoral Research Fellow, Muscle Physiology, Karolinska Institutet and Peter John Houweling, Senior Research Officer, Neuromuscular Research, Murdoch Children's Research Institute
- How humans evolved to live in the cold - Big Think ›
- Being fit boosts your tolerance for cold weather ›
- Spending the summer swimming? Get a full-body dryer - Big Think ›
A new paper reveals that the Voyager 1 spacecraft detected a constant hum coming from outside our Solar System.
- Voyager 1, humankind's most distant space probe, detected an unusual "hum" in the data from interstellar space.
- The noise is likely produced by interstellar gas.
- Further investigation may reveal the hum's exact origins.
Voyager 1, humanity's most faraway spacecraft, has detected an unusual "hum" coming from outside our solar system. Fourteen billion miles away from Earth, the Voyager's instruments picked up a droning sound that may be caused by plasma (ionized gas) in the vast emptiness of interstellar space. Launched in 1977, the Voyager 1 space probe — along with its twin Voyager 2 — has been traveling farther and farther into space for over 44 years. It has now breached the edge of our solar system, exiting the heliosphere, the bubble-like region of space influenced by the sun. Now, the spacecraft is moving through the "interstellar medium," where it recorded the peculiar sound.
Stella Koch Ocker, a doctoral student in astronomy at Cornell University, discovered the sound in the data from the Voyager's Plasma Wave System (PWS), which measures electron density. Ocker called the drone coming from plasma shock waves "very faint and monotone," likely due to the narrow bandwidth of its frequency.
While they think the persistent background hum may be coming from interstellar gas, the researchers don't yet know what exactly is causing it. It might be produced by "thermally excited plasma oscillations and quasi-thermal noise."
The new paper from Ocker and her colleagues at Cornell University and the University of Iowa, published in Nature Astronomy, also proposes that this is not the last we'll hear of the strange noise. The scientists write that "the emission's persistence suggests that Voyager 1 may be able to continue tracking the interstellar plasma density in the absence of shock-generated plasma oscillation events."
Voyager Captures Sounds of Interstellar Space www.youtube.com
The researchers think the droning sound may hold clues to how interstellar space and the heliopause, which can be thought of as the solar's system border, may be affecting each other. When it first entered interstellar space, the PWS instrument reported disturbances in the gas caused by the sun. But in between such eruptions is where the researchers spotted the steady signature made by the near-vacuum.
Senior author James Cordes, a professor of astronomy at Cornell, compared the interstellar medium to "a quiet or gentle rain," adding that "in the case of a solar outburst, it's like detecting a lightning burst in a thunderstorm and then it's back to a gentle rain."
More data from Voyager over the next few years may hold crucial information to the origins of the hum. The findings are already remarkable considering the space probe is functioning on technology from the mid-1970s. The craft has about 70 kilobytes of computer memory. It also carries a Golden Record created by a committee chaired by the late Carl Sagan, who taught at Cornell University. The 12-inch gold-plated copper disk record is essentially a time capsule, meant to tell the story of Earthlings to extraterrestrials. It contains sounds and images that showcase the diversity of Earth's life and culture.
As the American population grows, fewer people will die of cancer.
- A new study projects that cancer deaths will decrease in relative and absolute terms by 2040.
- The biggest decrease will be among lung cancer deaths, which are predicted to fall by 50 percent.
- Cancer is like terrorism: we cannot eliminate it entirely, but we can minimize its influence.
As the #2 leading cause of death, cancer takes the lives of about 600,000 Americans each year. In comparison, heart disease (#1) claims more than 650,000 lives, while accidents (#3) take about 175,000 lives. (In 2020 and likely 2021, COVID will claim the #3 spot.)
Headlines are usually full of terrible news about cancer. Seemingly, you can't get away from anything that causes it. RealClearScience made a list of all the things blamed for cancer — antiperspirants, salty soup, eggs, corn, Pringles, bras, burnt toast, and even Facebook made the list.
The reality, however, is much more optimistic. We're slowly but surely winning the war on cancer.
Winning the war on cancer
How can we make such a brazen statement? A new paper published in the journal JAMA Network Open tracks trends in cancer incidence and deaths and makes projections to the year 2040. The authors predict that around 568,000 Americans will have died of cancer in 2020, but they project that number to fall to 410,000 by 2040. That's a drop of nearly 28 percent, despite the U.S. population being projected to grow from roughly 333 million today to 374 million in 2040, an increase of 12 percent. That means cancer deaths will decrease in both relative and absolute terms.
What accounts for this unexpected good news? The lion's share is the number of deaths attributable to lung cancer, which is projected to decrease by more than 50 percent, from 130,000 to 63,000. This drop is largely due to the decreasing use of tobacco products. Other deaths predicted to decline include those from colorectal, breast, prostate, and ovarian cancers, among others, such as leukemia and non-Hodgkin lymphoma (NHL).
The authors credit screening and biomedical advances for saving many of these lives. For instance, lead author Dr. Lola Rahib wrote in an email to Big Think that "colonoscopies remove precancerous polyps." She also noted that targeted therapies and immunotherapies have helped reduce the number of deaths from leukemia and NHL.
We'll never cure cancer
Now the bad news: We'll never cure cancer. There are at least three reasons for this. The first is obvious: We all die. The lifetime prevalence of death is 100 percent. The truth is that we are running out of things to die from. After a long enough period of time, something gives out — often your cardiovascular system or nervous system. Or you develop you cancer.
The second reason is that we are multicellular organisms and, hence, we are susceptible to cancer. (Contrary to popular myth, sharks get cancer, too.) The cells of multicellular organisms face an existential dilemma: they can either get old and stop dividing (a process called senescence) or become immortal but cancerous. For this reason, the problem of cancer may not have a solution.
Finally, there isn't really such a thing as a disease called "cancer." What we call cancer is actually a collection of several different diseases, some of which are preventable (like cervical cancer with the HPV vaccine) or curable (like prostate cancer). Unfortunately, some cancers probably never will be curable, not least because cancers can mutate and develop resistance to the drugs we use to treat them.
But the overall optimism still stands: We are slowly and incrementally winning the war on cancer. Like terrorism, it's not a foe that we can completely vanquish, but it is one whose influence we can minimize in our lives.
China has reached a new record for nuclear fusion at 120 million degrees Celsius.
This article was originally published on our sister site, Freethink.
China wants to build a mini-star on Earth and house it in a reactor. Many teams across the globe have this same bold goal --- which would create unlimited clean energy via nuclear fusion.
But according to Chinese state media, New Atlas reports, the team at the Experimental Advanced Superconducting Tokamak (EAST) has set a new world record: temperatures of 120 million degrees Celsius for 101 seconds.
Yeah, that's hot. So what? Nuclear fusion reactions require an insane amount of heat and pressure --- a temperature environment similar to the sun, which is approximately 150 million degrees C.
If scientists can essentially build a sun on Earth, they can create endless energy by mimicking how the sun does it.
If scientists can essentially build a sun on Earth, they can create endless energy by mimicking how the sun does it. In nuclear fusion, the extreme heat and pressure create a plasma. Then, within that plasma, two or more hydrogen nuclei crash together, merge into a heavier atom, and release a ton of energy in the process.
Nuclear fusion milestones: The team at EAST built a giant metal torus (similar in shape to a giant donut) with a series of magnetic coils. The coils hold hot plasma where the reactions occur. They've reached many milestones along the way.
According to New Atlas, in 2016, the scientists at EAST could heat hydrogen plasma to roughly 50 million degrees C for 102 seconds. Two years later, they reached 100 million degrees for 10 seconds.
The temperatures are impressive, but the short reaction times, and lack of pressure are another obstacle. Fusion is simple for the sun, because stars are massive and gravity provides even pressure all over the surface. The pressure squeezes hydrogen gas in the sun's core so immensely that several nuclei combine to form one atom, releasing energy.
But on Earth, we have to supply all of the pressure to keep the reaction going, and it has to be perfectly even. It's hard to do this for any length of time, and it uses a ton of energy. So the reactions usually fizzle out in minutes or seconds.
Still, the latest record of 120 million degrees and 101 seconds is one more step toward sustaining longer and hotter reactions.
Why does this matter? No one denies that humankind needs a clean, unlimited source of energy.
We all recognize that oil and gas are limited resources. But even wind and solar power --- renewable energies --- are fundamentally limited. They are dependent upon a breezy day or a cloudless sky, which we can't always count on.
Nuclear fusion is clean, safe, and environmentally sustainable --- its fuel is a nearly limitless resource since it is simply hydrogen (which can be easily made from water).
With each new milestone, we are creeping closer and closer to a breakthrough for unlimited, clean energy.