Category Archives: Science

Killer Kittens Can Be Placated With Meat and Playtime, New Study Finds

It would be wise not to anger him.

Cats kill billions of animals yearly, but feeding them a meaty diet and providing lots of playtime can redirect them to less violent pursuits, a new study finds.

The mother of one cat in the study had seen her furry friend wreak havoc:

“We’ve had birds in the bedroom, rats in the paper bin, rabbits in the utility room, and several vermin that have died of fright,” says her owner, Lisa George from Cornwall, U.K.

But redirecting their prey drive to play, plus keeping them sated with meat, greatly reduced the body count:

the high-meat diet and playtime approaches had the most sweeping impacts, slashing all types of animals on the doorstep by 36% and 25%, respectively.

See the full study out today in Current Biology here.

A surprisingly large number of species have a prey drive. Our gerbil stalked, attacked and ate caterpillars, leaving only the legs. He also ripped the head off a cockroach and wisely left the remains for my wife to clean up rather than eating them.

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Photo: “killer kitty” by Ayeshah Ijaz is licensed under CC BY-NC-ND 2.0

Did You Know Dragonflies Can Do Backflips?

I came across this interesting new study today showing dragonflies can do backflips, even unconscious!

They found that conscious dragonflies, when dropped from the upside-down position, somersaulted backwards to regain the rightside-up position. Dragonflies that were unconscious also completed the somersault, but more slowly.

Check out the video below!

I happened to be watching a wonderful David Attenborough documentary on insects, including dragonflies, last night with my wife, so this interesting tidbit caught my eye! Nature continues to amaze me, day after day.

See the full study here.

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Photo: “White-faced meadowhawk dragonfly” by Tibor Nagy is licensed under CC BY-NC-ND 2.0         

What I Learned From James Watson, Co-Discoverer of the Structure of DNA

We wish to suggest a structure for the salt deoxyribose nucleic acid (DNA). This structure has novel features which are of considerable biological interest.

So begins the famous Nature paper by James Watson and Francis Crick, who discovered the structure of DNA in 1953. Their discovery revolutionized biology and won them both the Nobel Prize.

I just finished reading Watson’s book The Double Helix, and as a layman I found the inside view of the process of scientific discovery intriguing. What struck me most was the importance of collaboration.

We are used to thinking of scientists as lone geniuses hunched over a lab bench until they exclaim “Eureka!” But Watson’s book makes clear how important the many scientists surrounding him at the University of Cambridge were to his discovery. He repeatedly checks his findings with others more experienced than he in a particular area, like structural chemistry. And without the long conversations with Crick, the discovery would never have happened in the first place.

Being in the right environment was so important to Watson that he left the University of Copenhagen, against the terms of his fellowship, when he realized he needed the expertise of the Cambridge circle to make a real breakthrough. He did what was necessary and asked for permission later. What would’ve happened had he sat around waiting for permission?

The casual sexism with which Watson treats Rosalind Franklin, the expert in X-ray photography that wound up playing a major part in the discovery of the double helix, was striking to me reading the book in 2021. Watson tends to characterize her opinions and insights as obstinancy or rudeness. He doesn’t view his male colleagues the same way.

If cooperation is so critical to science, I can’t help but wonder what Watson could’ve achieved with a more collaborative attitude toward Franklin. Would the breakthrough have come even sooner? Would they have been able to make even more discoveries together if Watson had been more open to her expertise?

I loved getting a view of what is in a scientist’s mind as they make a major breakthrough. Watson was by no means certain he was right at first, but he worked methodically to prove what he suspected. That even such a genius has doubt in his ideas can cheer the rest of us!

The great chemist Linus Pauling had suggested a different structure of DNA, which turned out to be incorrect. But when he saw the elegance of Watson and Crick’s double helix, he was in awe and thrilled, rather than upset at being proven wrong.

I find that attitude to be one of the great things about science. There is both collaboration and competition, but in the end, everyone is working toward one goal: understanding.

In all, I found Watson’s book interesting and instructive. Since it was written in 1968, I’m not sure how many people are still reading it, but it’s worth a look. Check it out!

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What If Homelessness Is Caused by Brain Injuries?

A couple of months ago, a man approached me on the street near my home. He asked for a bit of money, and although I usually never do, for some reason I gave it to him. I later saw him on a regular basis near the neighborhood grocery. I found out his name was John* and he used to work in construction. Several times a week, I’d run into him and stop and chat for a few minutes.

One day, I noticed he had large purple bruises on his forehead. He told me he had tripped over his shoelaces and gone down hard. Especially if someone is exhausted and cold, it’s easy to see how this could happen. He had been to the hospital, but they dismissed him quickly, perhaps because he was homeless.

He had lived in our town for 48 of his 53 years, and only become homeless recently after losing his job, like so many others. It troubled me to think that after a lifetime of contribution, our town had cast him aside so readily.

I was reminded of John yesterday when I heard that over half of homeless people may have brain injuries. Skeptical, I decided to do some digging. I found a metanalysis in The Lancet that confirmed this astounding figure:

The lifetime prevalence of any severity of TBI [traumatic brain injury] in homeless and marginally housed individuals (18 studies, n=9702 individuals) was 53.1%

This is much greater than the general population:

The lifetime prevalence of TBI in homeless and marginally housed individuals is between 2.5-times and 4.0-times higher than estimates in the general population. Moreover, the lifetime prevalence of mo­derate or severe TBI in this population is nearly ten-times higher than estimates in the general population.

It’s difficult to say whether the brain injuries are a cause or effect of homelessness. But, homeless people tended to have their first TBI at a young age. To me, this argues that brain injuries are a cause of homelessness:

Age at first TBI ranged from 15 years to 19.9 years, and we calculated a weighted mean age of first TBI of 15.8 years.

Perhaps the relationship works both ways:

TBI could increase the risk for homelessness, and homelessness could increase the risk for incident TBI.

It’s common for us to blame the homeless for their condition. After all, many are addicted to alcohol and drugs, aren’t they? But that too may be related to head trauma:

several characteristics of homeless and marginally housed populations (eg, residential instability or substance use) were associated with sustaining TBI

Another study from Canada found similar figures, and noted that the first TBI usually happened before they became homeless:

The lifetime prevalence among homeless participants was 53% for any traumatic brain injury and 12% for moderate or severe traumatic brain injury. For 70% of respondents, their first traumatic brain injury occurred before the onset of homelessness.

A British study found that homelessness was not a significant predictive factor for head injuries. However, it didn’t address the question of whether the homeless had a TBI before becoming homeless.

Imagine two people, one with an stable and well-off family and one with a chaotic and impoverished family (or no family at all). They both hit their heads. One gets support and good medical care, but the other may wind up homeless.

I sometimes wonder if that’s what happened to John. Did he get hurt, wind up homeless, and then find himself in a position to get hurt again?

I haven’t seen him lately, despite looking for him over and over. I hope he found a nice place to stay this winter, and I hope to see him again.

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*Not his real name

Photo: “Thomas (Tomaso) is Homeless” by Franco Folini is licensed under CC BY-SA 2.0

Could a New Class of Antibiotics Put an End to the Most Deadly Infections?

When I worked in medical software, multidrug resistant bacteria were always a concern. But new research has created a class of antibiotics that may make even the most drug-resistant infections history:

[They] focused on a metabolic pathway that is essential for most bacteria but absent in humans, making it an ideal target for antibiotic development. This pathway, called methyl-D-erythritol phosphate (MEP) or non-mevalonate pathway, is responsible for biosynthesis of isoprenoids — molecules required for cell survival in most pathogenic bacteria. The lab targeted the IspH enzyme, an essential enzyme in isoprenoid biosynthesis, as a way to block this pathway and kill the microbes. Given the broad presence of IspH in the bacterial world, this approach may target a wide range of bacteria.

I found it fascinating that the scientists used computer modeling to winnow down millions of possible drug candidates to a few compounds most likely to work, then tested them for real. This reminds me of the CAD/CAM software that has revolutionized manufacturing.

These drugs could be used for a wide variety of stubborn infections, per the original paper in Nature:

they kill clinical isolates of several multidrug-resistant bacteria—including those from the genera Acinetobacter, Pseudomonas, Klebsiella, Enterobacter, Vibrio, Shigella, Salmonella, Yersinia, Mycobacterium and Bacillus—yet are relatively non-toxic to mammalian cells.

This research is in its early stages in mice, but the early results are promising. I can only imagine the many more incredible drugs that may come from using this type of computer modeling for drug discovery.

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Photo: “Salmonella species on X.L.D. agar.” by Nathan Reading is licensed under CC BY-NC-ND 2.0

What Is the Ideal Amount of Exercise?

Above: Me sucking wind after a tough workout.

We often hear what the minimum amount of exercise we need is, but what amount of exercise is actually optimal? At what point have we reaped all the benefits exercise has to offer, and possibly even gone over the edge into damaging overtraining?

With the largest snowstorm in years lashing my apartment today, I thought it was as good a time as any to try to find an answer.

The federal government recommends a minimum of 150 minutes of moderate activity or 75 minutes of vigorous activity per week. This establishes a useful lower bound we definitely shouldn’t dip below, but a highly cited study in JAMA Internal Medicine finds that you can get further longevity benefits by exercising a lot more:

the longevity benefit threshold appears to be approximately 3 to 5 times the recommended physical activity minimum

So, in order to be sure to get the maximum longevity benefit, you need to do five times the minimum recommended level of exercise. 5x the minimum recommended level would be 1 hour 47 minutes of moderate activity daily or 54 minutes of vigorous activity daily.

Furthermore, the study found no danger from exercising even more than what it takes to get the full longevity benefit:

there does not appear to be an elevated mortality risk with LTPA [leisure time physical activity] levels as high as 10 or more times the recommended minimum.

Looking at the differences between moderate and vigorous activity, I also wondered if one is better than the other. There doesn’t seem to be solid data to say that either moderate or vigorous activity is superior from a health perspective:

comprehensive reviews of the literature on physical activity and mortality report that overall volume of physical activity is associated with lower mortality risk but report mixed findings on the relative contributions of moderate- vs vigorous-intensity activities

So am I doing enough? Looking at the pedometer app on my phone, I’ve averaged 2.75 hours per day of walking (moderate intensity exercise) over the past year. I also do about 3-4 hours a week of vigorous exercise (yoga and strength training, mostly), so about 30 min daily.

So, I seem to be comfortably above the level needed to get the maximum longevity benefit. That said, counterintuitively, I sometimes find my mood is a little lower on days I don’t do vigorous activity. (You think you’d be happy for a rest day, but maybe not!) Just because I’m at the maximum amount of exercise to produce longevity benefits doesn’t mean that more exercise might not produce other benefits in terms of mental health, athletic ability, appearance, etc.

Since there appears to be no harm from even very high levels of activity, I may add another vigorous workout (likely yoga or calistenics) to my routine some weeks, depending on my schedule and desires at the time.

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New Research Identifies the Key Causes of Aging

Dr. Jeremy Walston, Professor of Medicine at Johns Hopkins University and co-author of the study

I just read an interesting new study identifying the biggest causes of aging. The authors gathered a panel of leading experts on health and aging and asked them what the biggest risk factors are for failing health as the years go by. Here’s what they found:

Experts identified 13 factors predisposing to or clinically manifesting AACD [accelerated aging and cellular decline]. Among these, chronic diseases, obesity, and unfavorable genetic background were considered as the most important.

Early detection of accelerated aging and cellular decline (AACD): A
consensus statement

None of the risk factors will shock you, but seeing all the key risks laid out in order of importance can really help guide our decision making:

One risk stood out above all:

smoking was consistently viewed as the most prominent risk factor

So if you’re smoking, definitely consider quitting! I recently shared how I put down the cigarettes 6 years ago. Hopefully my experience can help.

These risks mostly boil down to either what you put into your body or what you do with your body. Here’s how I try to mitigate these risks:

  • Sleeping 8-9 hours a night
  • Exercising at least 4 times a week, in addition to walking at least 4 miles every day
  • Eating a lot of fruits and vegetables and avoiding too many processed foods
  • Meditating most days, generally for 10-20 minutes

Although I did, incongruously, read this article while eating some potato chips, so there’s room for improvement! 🙂 Have a great weekend everyone!