IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later in the hour, we’ll explore the future of batteries, a key to realizing the vision of a decarbonized reliable grid. But first, weird weather is on everybody’s mind, right? Unbelievable flooding in Germany, mudslides in Japan. Here, heat like we’ve never seen it before.

And if you think about it, it’s not just people feeling the heat. The wildlife are being affected, too, in ways that you might not expect. Amy Nordrum has been following the heat. She’s here with that story and other science headlines this week. Amy is an editor at MIT’s Technology Review. Welcome back, Amy.

AMY NORDRUM: Hi, Ira. Thank you.

IRA FLATOW: You’re welcome. OK, let’s talk about this. So the consequences of heat on wildlife.

AMY NORDRUM: Yes, California’s Department of Fish and Wildlife said this week, that they’re expecting almost all of the juvenile Chinook salmon in the Sacramento River in California to die this year because of the extreme heat that they’ve been dealing with.

IRA FLATOW: All the salmon to die, wow.

AMY NORDRUM: All the salmon, that’s right. And this is a key time for salmon in that river. The adult salmon have come back to the river from the ocean, and they’ve laid their eggs earlier this year. And now those eggs are incubating for a while in the river before turning into fry. But if the water temperatures get too warm, these eggs won’t hatch.

And the recent heat waves are causing those water temperatures to rise above the levels that they can survive. And the whole problem is being made worse by drought, which is affecting the whole state right now, and especially the area around the river– just less water overall and making that water easier to be heated down at the bottom, where the eggs are.

IRA FLATOW: Of course, this extreme heat has us all thinking about climate change and the link between the two. And I understand there is a new study out about the urban contribution to greenhouse gas emissions. Tell us about that.

AMY NORDRUM: We hear and talk a lot about federal policy and national commitments to reduce emissions. And those are important, of course. But cities can also have a big impact because most people who are alive today in the world are living in cities. So there’s a new study out this week that gave us some interesting data on this. They looked at more than 160 cities worldwide and found that just 25 are responsible for more than half of all greenhouse gas emissions produced by all the cities that they looked at.

And almost all of those 25 cities were in China. But they also looked at cities on a per capita basis, so how many emissions per person the cities emitted. And by that measure, some of the world’s most polluting cities are right here in the US, places like Los Angeles, Washington, DC, Chicago, and New York City.

IRA FLATOW: Wow, that is an interesting story. Let’s talk about other environmental news. There was a new list of chemicals to keep an eye on. And it includes something new.

AMY NORDRUM: Right, yes, the EPA announced on Monday that it was adding a family of synthetic chemicals, known by the acronym PFAS, to a list of wastewater contaminants that it was considering regulating. So these chemicals are used in all kinds of things to make them resistant to heat or water, stuff like fabrics and paint and cleaning products. There’s thousands of different kinds.

And they’ve been nicknamed forever chemicals because they don’t break down in the environment, and they can build up and accumulate in the body over time. But they aren’t regulated currently in drinking water. There’s no limit to how many of these chemicals can be in your water. So that’s what the EPA indicated it was interested in doing by adding them to this draft list.

IRA FLATOW: And we find these chemicals in flame retardants, nonstick coatings, and as you say, they’re forever.

AMY NORDRUM: That’s right, yeah. I mean, there was a study published last year that estimated as many as 80 million people in the US might have PFAS in their drinking water. And the nonprofit Environmental Working Group also found it in rainwater and in almost all of the tap water that they tested across the country. So this draft is now open for public comment. And it may still be a few years before the list is finalized and any regulations are in place. So it’s kind of a first step in a long process. So this is a step in that direction.

IRA FLATOW: Let’s turn to the ubiquitous COVID news. The pandemic, it appears, has evolved into two societies, and I mean those who are vaxxed and those who are not.

AMY NORDRUM: That’s right, especially as the Delta variant takes hold. I mean, it’s now responsible, as health officials predicted, for more than half of new COVID-19 cases diagnosed here in the US. And people who are fully vaccinated are well protected against this variant.

But those who are unvaccinated or those who are only partially vaccinated and just got one dose of the Moderna or the Pfizer vaccines, they’re at greater risk because this variant is more transmissible than the original one. So we’re seeing increases in the number of cases, hospitalizations, and deaths in places that have low vaccination rates. And virtually everyone who’s hospitalized or dying of COVID-19 now in the US is unvaccinated.

IRA FLATOW: And we do have cases of people who have been vaccinated and are hospitalized, but they are not in the high danger category.

AMY NORDRUM: Right, yes. They’re not as likely to die or have severe illness as those who were unvaccinated who are stricken with the Delta variant.

IRA FLATOW: And it seems weird– I guess I’m using that word pejoratively– to see that Tennessee has moved the dial backwards on its efforts to encourage kids to get vaccinated, and not just for COVID, but for all vaccines.

AMY NORDRUM: Yes, the state health department decided to, really, stop all of its outreach it was doing to teens to get them vaccinated, as you say, for COVID-19, but also for other things, like HPV. And the top vaccine official in the state said this week that she was fired for trying to reach out to teens and encourage them to get the COVID-19 vaccine. Now they were putting out public service ads to teens specifically and holding some of their vaccine events at schools. And it’s no longer going to be doing any of that after being criticized by some Republican lawmakers.

IRA FLATOW: Yeah, this seems like a purely political move.

AMY NORDRUM: Yes, absolutely. Yeah, certainly not in the interest of public health, it would seem.

IRA FLATOW: Let’s talk about some hopeful COVID news. There’s research into a kind of multi-antibody against all coronaviruses.

AMY NORDRUM: Right, yes. So scientists took antibodies that COVID-19 patients or people who had a similar virus had produced, and they tested them against all kinds of different coronaviruses. And they found one antibody that could bind to all different variants of COVID-19, as well as even to other coronaviruses, which could potentially be useful in treating patients.

IRA FLATOW: And so that’s basically just basic research. People are going to say, when can I get that vaccine, right? We’re not even close to that yet.

AMY NORDRUM: Right, this was just an initial result that was reported. There’d still be a lot of steps to getting this approved as an actual treatment. There are a few antibody treatments out there already, so this could be another option to help patients who did get COVID-19 and are hospitalized to recover more quickly. This could be another option for them eventually.

IRA FLATOW: You have a story this week about a group of ransomware hackers vanishing. Tell us about that.

AMY NORDRUM: That’s right. Yes, so ransomware, it’s a certain kind of attack where hackers remotely take control of your computer and demand a ransom to return access to you. And Patrick Howell O’Neill reported on this for us this week. There’s a notorious gang of ransomware hackers who are believed to operate out of Russia or with Russia that has been responsible for a number of very large ransomware attacks in even just the last few months.

But on Tuesday, they actually went dark. The websites and servers they had used to run their criminal operation all went offline at around the same time. And security experts really don’t know why, whether it was Russia cracking down or the US officials taking them offline or the group just deciding to give up, possibly go under the radar and reappear later. So we don’t know exactly how long this would last or what was behind it. But in the short term, anyway, security experts were excited to see this happen.

IRA FLATOW: Because President Biden said he told Putin to “cut it out,” I think he said it something like, or else. So we don’t know if Putin actually “cut it out,” meaning that he stopped the hackers or that something else happened.

AMY NORDRUM: Exactly, it’s not yet clear yet what the causes behind this group’s removal or who was responsible. But yes, the US has certainly been putting a lot more pressure on Russia and other countries as well to crack down on the cyber criminal gangs and circles operating within their borders.

IRA FLATOW: A few weeks ago, we talked about the controversial Alzheimer’s drug, aducanumab, which was approved despite pushback from Alzheimer’s experts. And it also had a really serious price tag on it. This week, the FDA pulled back on that approval somewhat. And a few major medical centers said that they wouldn’t plan on prescribing the drug. But you have a story about an Alzheimer’s approach that may be even more helpful and a lot cheaper.

AMY NORDRUM: Absolutely, it’s free, in fact, almost or virtually. Yeah, there’s been a lot of attention over the years on developing new pharmaceuticals for Alzheimer’s and other forms of dementia, of course. But new research published this week in neurology showed the benefits of just keeping your mind active later in life as a way to fight against these diseases.

So the analysis followed almost 2,000 older adults over a period of about seven years. And they tracked how often these people did really simple activities, things like puzzles or reading a book or a magazine or certain kinds of games, like chess or checkers. And they looked at whether there’s an association between doing these activities and when people in the group developed Alzheimer’s.

And those who did them the most often, they found, which was, like, several times a week, developed symptoms, on average, of Alzheimer’s five years later than those who did them the least often, which was just a few times a month. So there seemed to be a strong association here between doing these activities a few times a week and delaying the onset of Alzheimer’s disease.

IRA FLATOW: And that is interesting because we always talk about anecdotal evidence about do puzzles, try doing this with the mind tricks. But this is really concrete evidence, right?

AMY NORDRUM: Right, yeah, it was a very strong robust study. And there’s been evidence over the years that this might be a good thing to do. But this is the first time to really put a time to it, how long does this help you delay these symptoms. And it really does seem to make a big difference.

IRA FLATOW: Finally, I want to ask you about a study where slime mold– slime mold is making decisions. Tell us about that.

AMY NORDRUM: Yes, so as it turns out, organisms that have no brains can still make decisions, according to a new study published this week by researchers at Harvard and Tufts University. The team grew a certain type of slime mold in a Petri dish and arranged glass discs around the outside. And they found that the mold was growing in the same direction the vast majority of times, toward where more of the discs were concentrated.

And they think that certain ion channels in the mold have helped to detect the forces around it in its environment, like the strain created by these discs’ weight, and decided to grow in that direction. So it’s a pretty interesting situation where something without a brain can still make a decision and have a form of cognition.

IRA FLATOW: So what was the slime mold looking for? Did somebody put bait, like in a mouse trap or in a maze? What was the motivation for making that decision?

AMY NORDRUM: Well, that’s one of the interesting things, is there was no food available to it. There was no chemical signal in this experiment. It was just a purely a physical force. So it was the weight and the distribution of these glass discs that it was attracted to. And the scientists I spoke with said that might have been kind of a proxy for what they might be looking for in the wild, like a log that was falling over or a tree or something that has a lot of mass that is distributed over a wide area. That’s their theory, anyway, as to why it moved toward the area where there were more of the discs concentrated.

IRA FLATOW: So it had to make a choice which direction to grow, and it made a choice.

AMY NORDRUM: It did. It made a decision. It was most of the times they tested it, it did the same thing. So it seemed to be a deliberate choice, yeah, and a really interesting case of this organism making a decision in a way that we wouldn’t typically think of decisions being made.

IRA FLATOW: Well, I have to make a decision to end our conversation, although I wish we could go on, Amy. Thank you for taking the time to be with us today.

AMY NORDRUM: Thank you, Ira.

IRA FLATOW: And some people have accused me of being sort of like a slime mold. Amy Nordrum, commissioning editor at MIT’s Technology Review, always great to have her with us.

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