For the increasing number of people who have cataract surgery, the eye’s lenses have ben replaced with plastic, which usually have a fixed focus. (Artificial lenses that can be focused are under development.)
My dad recently had cataract surgery and I just assumed he was getting would be a deformable lens that would give him the ability to focus again. Does anyone know why it is so hard to develop such a lens ? As far as medical breakthroughs it seems like low hanging fruit and most people over the age of 45 could benefit from such a surgery since that is the age at which our lenses begin to harden and can no longer be shaped by our ciliary muscles.
The lens is suspended by a ring of fibres about 1-2μm thick from the ciliar muscle. Getting accommodation to work with a synthetic lens would require a substitute suspension mechanism to attach the lens to the muscle. And it would probably be useful if it could be implanted without temporarily removing the front or the eye including the iris.
Compare that to a small cut to the side of the eye to extract the old lens and inject a new one that is held in place mechanically.
One of the very real dangers is that all of the satellite constellations come one line at the same time, and none of them get to critical mass before they all go bankrupt.
Mass adoption is the key to reasonable per-user costs here.
Amazon, and possibly SpaceX are at an advantage here, since they have other revenue streams, so they might be able to wait out the rest of the field and grab customers from failed networks.
Amazon and SpaceX are nowhere near equivalent. SpaceX is relying on starlink to be a major portion of their revenue by 2025, far outweighing launch. That's all they have.
Amazon has retail and aws, and satellites will be nowhere near a majority.
In addition to those consultants, Cynthia Stine of egrowthpartners.com was recently interviewed in The Week's Jan 25, 2019 "The Last Word" column and her firm helps Amazon Sellers with Marketplace challenges.
Also, Amazon's Selling Partner Summit is taking place next week at Amazon HQ. It is currently sold out but maybe there is a waiting list ? I'll be attending primarily to make internal contacts should I ever encounter a problem with my account but I can't say for certain if that conference will be helpful in that regard. Sorry for this situation and good luck!
This article implies that if you can't change your diet then you could achieve similar results with chewing exercises. The comments below mention mewing, but I suspect greater force would be better. Googling "chew toys for adults" gave interesting results but they are mainly used for anxiety and ADHD. Curious if anyone knows of a chew appliance for children or adults that would address the issues mentioned in the article.
A bit of a tangent, but does anyone know if a "paper PhD" is still and option ? The first and only time I ever heard of it was during a lecture by Nobel laureate Dr. Shuji Nakamura[1].
IIRC, the University of Florida offered PhD's if you published 5 papers which he did in one year.
It’s called a “sandwich thesis” and it’s quite common in some countries, mostly in Europe. Put together a few papers published in peer reviewed journals, write a introduction, and submit it for defense.
It's fairly common at my university. You publish 3 papers surrounding a singular theme or topic and you use that for your PhD. You still need to write an intro and have some boilerplate stuff, but it's not uncommon at all.
Although the number is shrinking, it's still a thing in Japan (so-called "ronpaku"). It is generally said that the thesis by a paper PhD must be better than those regular PhDs who completed courseworks, but it's much more efficient. If your thesis is already complete, you can get a degree in less than a year.
some programs are happy to just have you tack a bunch of papers together into a dissertation. they usually still require you to write the actual document, though, re-explaining the work in each paper.
Perhaps skin samples from different parts of the body would yield different age predictions. The actual study makes no mention which seems like a significant omission if someone were to try to reproduce this experiment.
Unless they’re dense they used the inside of the upper arm to avoid sun damage.
The bigger issue is that Steve Horvath calibrated and has successfully marketed a DNA methylation based “epigenetic clock” accurate to within a couple of years, from blood, with hundreds of not thousands of citations and successful replications since 2013. DNA is more stable than RNA, and blood is easier to come by than fibroblasts (skin punches), so this seems like a nonstarter to me.
Horvath’s clock works in arbitrary other tissues; we’ve applied it to pediatric and adult tumors, adjacent normal, and blood samples at diagnosis, remission, and relapse, and it works quite well (unlike the knockoffs that followed). I don’t see the point of a less reliable, less proven clock on less stable molecules (RNA), when I can use a handful of targeted amplicons to run Horvath’s for $30/sample on blood DNA (even dried blood) or other tissues.
"It's time to invest and avidly pursue a new wave of technological solutions to this problem - including those that are risky, unproven, even unlikely to work".
I had a recent crackpot idea that falls into the "unlikely to work" category since my background is not chemistry.
Given that a modern automobile's tailpipe emissions are mostly C02 + H20, those molecules can be converted into ethylene (C2H2) using known efficient electro-catalytic processes. The conversion of ethylene gas to a polyethylene (plastic) is well known and has the added benefit of being exothermic.
The end goal is for my car to output a lump of plastic I can drop into the recycling bin instead of CO2.
But my gut tells me that:
1) There is no way to speed up the reactions to keep up with the 80 liters per second of tailpipe exhaust (~40rps * 2.0 liter engine) without this system being impractically large and/or requiring energy intensive compressors.
2) No one, including me, wants to drive around with a tank of hydrogen and a tank of ethylene gas.
But still, it might be fun to hack on something like this assuming I can do it safely. If anyone has any feedback, or has experience making polyethylene, I would be grateful for feedback even if it is negative. Thanks.
The short answer is that while that reaction works in a beaker, it is too slow, inefficient and fragile. Plus there's also the thermodynamic perpetual motion machine in using the energy from a combustion reaction to reverse that combustion reaction.
Basically you'd need a second car worth of engine to generate the electricity to convert 1/3ish of the co2 from the first engine to ethylene (the rest winds up as methane, ethane, and CO.). Plus storage, maintenance and misc.
There are a few reviews by Hori that are more or less the gold
standard on the chemistry if you want to read more. Unfortunately the literature is full of fud though.
3) The energy content of the hydrogen tank needs to be greater than the energy content of the fuel tank.
And if you were going to add such a huge hydrogen tank to the car, and keep it filled, it would be simpler to use the hydrogen itself as fuel. Many people have indeed proposed hydrogen powered cars. Hydrogen powered cars in turn don't look like they have a very bright future because battery electric vehicles are reaching mass production first, and because batteries are more energetically efficient than storing/transforming energy via hydrogen.
Then forget exercise for now, just take a contemplative walk around the block. Perhaps do it right before breakfast and/or after dinner. It's easy and takes less than 10 minutes. Don't think of it as exercise and do it in any clothes and with any shoes. No excuses, anyone can walk around 1 block and everyone needs 10 private minutes to collect their thoughts.
Before you know it you'll find yourself walking around several blocks, then swinging your arms, then walking faster, then you may even start jogging. You'll feel motivated, you'll keep making progress, and most importantly, you'll actually look forward to your walks.
I followed the advice above and now run almost daily before sunrise. It has really boosted my self-esteem since I had always disliked running yet admired those people who run before sunrise. But if someone had told me to start by purchasing running clothes, finding the right running shoes, choosing a good running route, stretching for 10 minutes... forget it! However, I will make one recommendation. This mask is helpful on mornings when it is below 40F. https://www.amazon.com/gp/product/B0796R1DPG . Please, start tomorrow morning and report back. :)
I got into running, thinking that I wanted to try for a half-marathon. I actually worked up to the distance surprisingly quickly. I was under 30 at the time and it took like 2 months, and before that I wasn't running at all or doing any other exercise regularly. I started having some knee pain (flat feet don't help) and stopped after it became painful to run even a mile or two. About a year later, I fell on a skateboard on the same knee and injured my bursae. I fear that my running days are over, but it was kind of fun in a weird way after you get past ~mile 4. I still go mountain biking occasionally and enjoy long walks (on vacation I'll walk 15+ miles in a day).
Something like 50% of runners get injured in a given year. It’s insane. Do something that’s easier on your body. If you want cardio, hike or bike. I like weight lifting, personally. If you want to try weight lifting, check out Starting Strength.
> Something like 50% of runners get injured in a given year.
That's because most people use bad technique and would probably benefit from strength training as well. Sitting all day and then expecting your body to run for 30-60 minutes and then sitting again will lead to high risk of injury. I see a lot of people run like they're walking with longer strides, or hunched over, or any number of bad habits. The feet should land under your center of mass, not in front of it, and the turnover should be pretty fast. Short and fast steps instead of long and slow. Don't run too fast, use your core for stability, and keep an upright posture, slightly leaned forward at the ankles.
Look up proper running form, do some drills, and add body weight strength training a couple of times each week if you're thinking of starting running.
that is because most runners use padded shoes, which enable you to run in a totally unnatural way.
>this kind of collision leads to a rapid, high impact transient about 1.5 to as much as 3 times your body weight (depending on your speed) within 50 milliseconds of striking the ground (see graph a below).
>This is equivalent to someone hitting you on the heel with a hammer using 1.5 to as much as 3 times your body weight. These impacts add up, since you strike the ground almost 1000 times per mile!
is really fun to read, it is about a indigenous tribe in mexico which run in sandals cut from old tires, for 24 or 48 hours straight. In there is a reference to another study where they found a correlation between cost of the shoe and the rate of injuries: more expensive shoes with better damping had higher rates of injuries, they weren't expecting this.
Our legs evolved to store the energy in our tendons and release it to propel us forward. A QUARTER of the bones in our body is in our feet! Humans evolved to be the best endurance runners on the planet, being "naked" (without fur) is actually an advantage for running, enabling us to cool down our bodies by sweating. There are still tribes hunting their prey by running after it for prolonged periods till it collapses from overheating. There are races for horses, humans started to compete in. Initially the runners where ridiculed but someday a human won the race.
And most importantly, don’t bereft your brain from useful feedback from your foot! Use thin (unpadded) rubber soles on your shoes. If your feet are getting painful, probably they are saying something useful about your knees as well.
No way. That's not true. I've been running for 10 years now. Never have I been injured. Also my friends did not suffer injuries neither.
If you like lifting, that's fine. But that does not mean running is worse that lifting or that you could even compare them. It just means that you are used to lifting and you are rationalising your choice.
For anyone worried about knee injuries from running, or shin splints I can highly recommend weightlifting, in particular squats, as an auxiliary exercise. I kept on running, getting pains in my knees and resting for two weeks and then just doing it again. After six months (way longer than probably necessary) of progressively lifting higher weights I went back to running and I’m doing my first 50K next week, having done a 35K up and down mountains previously. My first run after the long period weightlifting I just decided to run a half marathon distance to see if I could. The muscle pain the next day was less than I often get from lifting.
I do tennis a few hours a week and my knees have started hurting after a period of summer inactivity. I'm thinking of taking up gym squats again, my knees never felt better than when I was squatting. I could effortlessly climb up stairs like it was nothing with just a few weeks of weightlifting, I need to get back on that (and recommend it to anyone).
Thanks. I love how practical your advice is. Going to do this tomorrow. Maybe it'll even help align my sleep schedule. My wife is up at 6 and I always sleep in to 8.
Additional advice: Bring some headphones and listen to great music or continue your favorite podcasts. Time will fly if you add a soundtrack to your walk.
For the increasing number of people who have cataract surgery, the eye’s lenses have ben replaced with plastic, which usually have a fixed focus. (Artificial lenses that can be focused are under development.)
My dad recently had cataract surgery and I just assumed he was getting would be a deformable lens that would give him the ability to focus again. Does anyone know why it is so hard to develop such a lens ? As far as medical breakthroughs it seems like low hanging fruit and most people over the age of 45 could benefit from such a surgery since that is the age at which our lenses begin to harden and can no longer be shaped by our ciliary muscles.