twawaaay

I think you have very different idea of what "change in laws of physics" means.

I am using "Switching Power Supply Design" from Pressman, Billings and Morey and "Switmode Power Supply Handbook" from Billings and Morey.

Both are excellent resources and look at design from a bit different point of view.

I think the biggest problems with swithing designs are not what you have listed, although both noise and failure modes are a huge problem and main cause of concern (and cost) when certifying your designs.

The biggest problem is that they are just so damn complex and they have so damn complex characteristics over time and operating parameters. You might think you understand how a switching PSU works but that's just an illusion. There are people who spent their entire life specialising in switching PSU design and are still learning. At best we can understand how they behave within certain parameters and then try to make sure to shut it down safely when we leave those parameters.

Yeah. I use a lot of linear regulators. And they have even more advantages. For example, they are simple. They do exactly what you think they do. They don't leak. They don't create noise. They convert voltage right away and you don't need to wait for it to stabilise. And they have simple failure modes. You just throw in one part and it magically converts voltages. What simpler thing you would really want?

In most realistic designs you put multiple power supply rails in your designs because you need a lot of parts that don't need a lot of power but have different voltage requirements or might need voltage offset. In those cases linear regulators are perfect solution.

More than that, those power supply rails usually have standard voltages and there exist standard linear regulators that output those voltages to make everything even easier.

My strategy is to use linear regulators default and only use anything more complex on those voltage rails where I need to step the voltage up or where the inefficiencies would affect my design's performance significantly enough for me to care.

Oh, and use voltage dividers if you want to convert signal levels (unless it is fast signal and you care about signal integrity).

What you say doesn't make much sense.

AFAIK there exists no popular belief that physics was different in early universe. The physics was the same, the only thing that was different was physical conditions. Meaning everything was densely packed together.

If you, even for a moment, assume that laws were different in early universe then you essentially lost any possibility to predict anything.

Contrary to some opinions here, I think this is very good advice.

I am always giving as much notice as I can. And also try to finish my projects and accommodate my employer/client as much as I can at the end of the project.

Regardless how unprofessionally they may act, I resolve to always act professionally myself.

I think it is more about the attitude rather than simple cost/benefit calculation.

But even if you are just looking at cost/benefit, after two decades of doing this I am finally seeing people noticing and coming back to me. I have my past bosses bringing new work to me, I have my colleagues spreading information about me by word of mouth. I have CEOs of unknown companies reach out to me because they learned about me from somebody who worked with me in the past.

Maybe you will not get noticed when you are junior level but when you get a bit more exposed position it starts becoming more and more important.

> The key point though is that their mechanism cannot work in vacuum. It absolutely requires that the light travels significantly slower than the gravitational radiation

I am not a physicist, but I understand we are talking about Universe so early after Big Bang that it wasn't yet transparent to light. There simply wasn't vacuum yet if by vacuum you mean electromagnetic waves being able to travel long distances.

No. That's far beyond our capabilities. Somebody calculated that LHC would have to be over 1000 light years in diameter to do this (and then still we would have to wait for thousands of years for particles to get accelerated).

> We have been hearing this for a decade,

But that's not true. What we have been seeing was attempts that looked marginally useful. Helpdesk chats that were only able to handle simplest problems and would respond with something stupid more often than not. Things that did not really look threatening to actual people doing their jobs well.

What I saw recently, on the other hand, is something that can actually perform useful, novel work and that can actually replace some marginally productive people. And this is very important difference.

I am not a huge fan of AI but I cannot deny this is probably biggest game changer since smartphones came out.

I find it a bit strange (although entirely predictable) that some people would try to forget about whole matter and hide from it as if it did not exist. The reality is that the IT world is going to go through some fundamental shifts in near future and very likely a lot of people will either lose jobs or do completely different work or do it with a completely different set of tools and skills.

We are now all trying to figure out what's in store for us and prepare for it, or be left out.

I find articles on HN actually pretty useful. And unlike some other hysterias, the whole preoccupation with AI to be healthy and useful.

One thing is sure, I would not want to be a UI dev in Mongolia...

I specifically, for this reason, not to mistake my (not even opinions but just thoughts) with this disclaimer:

> Given this I wonder if it is possible at least for some people with diabetes...

I am fully aware that diabetes is a dangerous, life threatening condition and that you can't do the same things that are totally fine for a healthy person.

And while I do not agree with some of the treatments for diabetes, it is just my own opinion and everybody is responsible for their own health and in doubt they should follow their health professional's advice.

Now... given the above disclaimer so that nobody confuses what I am about to write as an actual medial advice... I have just lost 1/3rd of my body weight and feeling absolutely fantastic by doing exactly the opposite to what health professionals are saying. I also observe a lot of people struggling to get any lasting effects by following the popular, official advice. I am angry and feeling powerless to the inertia of the health establishment and forces that do not really want people to get healthy but would rather avoid change that would disrupt their jobs, keep pushing medication that could be easily avoided for most of the people.

I have learned that so many "professionals" do not really understand what they are talking about. And it should not be a surprise, when you go to multiple "professionals" for advice and they give you opposite advice.

Just yesterday I had to visit an ophthalmologist to remove a foreign object from my eye (a piece of eyelash that got stuck for the past week). I had to spend at least 20 minutes to hear his ranting about how improper glasses I wear and how this is going to damage my vision. About a year ago I red (here on HN) that you can actually reduce your shortsightedness by slowly reducing the strength of your glasses which I have been doing successfully for the past year. I went from -3 diopters to -2 diopter glasses. I am currently seeing perfectly with -2.25 diopter glasses and I am using slightly lower strength for most of the day except for driving a car. Some of the stuff he said is that "This has been proven not to work by a study X", and "This is going to my shortsightedness to only deepen" (when exactly opposite has been happening) and that "If there are any result this is only my imagination" and "If I am seeing well at -2.25 it must be because my previous prescription of -3 diopters was wrong".

I am grateful that I am intelligent person that can read and make my own opinions but I am dismayed that people who can't do the same have to rely on those fucking idiots for their health.

It is interesting but my data is useless. I lost over 70 pounds since July last year but I don't have any good record of blood sugar measurements. I did measurements whenever I liked either to confirm I am in ketosis or just to check my blood sugar / ketone levels in response to how I felt or to check how much various meals raised my sugar. But I did not keep any log.

There is couple things I learned. When you are on a strict ketogenic diet your blood sugar pretty much stays the same throughout the day. Even if I eat one huge meal for entire day, my sugar after the meal is pretty much the same as before the meal or within 10mg/dL. My exercise and circadian rhythm affect sugar more than meals.

Given this I wonder if it is possible at least for some people with diabetes to skip carbs completely and live carb-free but also insulin-free life.

Another thing I learned is that as I started my first keto month, your blood sugar starts dropping, then goes back up after about two weeks. Coincidentally, I also felt pretty poorly for those two weeks and my running performance dropped dramatically until my body adapted. The second time I started keto (after two months of break from it) I have seen nothing of the sort. Actually, I feel (but don't have good enough record to be sure) my blood sugar got a bit higher. But I have only been doing regular sugar measurements when I was in keto so I don't have data for sure.

My blood sugar goes below 60 but I am not hypoglycemic and no, the alerts are not useful. And yes, the measurements are correct -- I have more than one way to measure blood sugar level.

Hypoglycemic means your body is dependant on sugar, can't get sugar and has adverse reaction to it.

My body can't get sugar, true, but is not dependant on it (fat adapted) and I have no reaction to it.

As I have not eaten any carbs for about two months any notion of hypoglycemia due to not eating sugar is a bit meaningless.

I know people who get much, much lower blood sugar levels and feel fine. The levels they get would (below 40? below 30?) would be lethal to "normal" person, if sugar addiction can be called normal at all. But they all feel fine and are probably healthier than most.

I put CGM on my arm to learn how my blood sugar levels look when on my diet and then what happens when I switch carbs back on -- I expect my body to "freak out" a little bit and then stabilise within couple of days and that's what I would like to see in a bit clearer detail using my CGM.

As to driving the prices down... nah, I am not making a dent. These devices are too expensive to use regularly even for me (software devs salary). I will just put a couple of them to learn a bit about myself and then stop when I got what I needed.

Can confirm. Just at this moment I have a Dexcom G7 attached to my arm and I don't even have diabetes. Just using it to learn a little bit about my blood glucose patterns.

But these devices are not really built for non-diabetics. There is a constant barrage of alerts as my blood sugar regularly dips into hypoglycemic levels. I feel fine but the device purposefuly does not have any way to disable the alarm.

I can make good tasting beef broth but I usually don't even bother.

I make a huge, 15L pot of broth. I use various pieces of meat, especially ones that have a lot of collagen. If I think I have too little cartilage I will add achilles tendons which are pretty much pure collagen. I brown everything them either on a pan or in the oven and I simmer it for at least 12h until all meat disintegrates and all collagen and fats dissolve. I then remove and discard meat and bones and small particles by filtering it through fine mesh strainer, I remove (and store) the tallow. And then I reduce everything about four-five times to get the meatiest substance on Earth. Cool it down, it should completely congeal in room temperature. I cut it into cubes, throw it into plastic bags and into the freezer. Then whenever I want to make soup or a sauce or risotto or whatever else, I just take some cubes from the freezer and drop directly into the pan or pot.

I also make and freeze other useful things. For example, I always keep a supply of bolognese sauce which I make 9L at a time and then lasts me for a year.

You are right. Just because food is fatty doesn't mean it is healthy. I did not want to make the comment too long but there is the concern for the quality of fats which is pretty complicated problem. There are some simple rules -- for example you definitely want to stay away from highly processed fats. But further than that things get more complicated.

As an example, we are told that fish is generally one of the healthiest fats around. But what people forget is that this is assuming wild fish and the kind that does not accumulate rare metals. Salmon is pretty health... unless we are talking farmed salmon. Farmed salmon is fed with highly processed, carbohydrate-rich feed which completely changes the fat content of the salmon making it very high omega 6 to 3 ratio. And God knows what else...

Beef tallow -- I have simple solution for this at least for my home use. I buy lots of quality red meat. Whenever I may broth or render fats for any reason, I gather them all and store them for later.

And this is meant to be proof of what exactly?

Somehow doing one thing right is supposed to prevent obesity in every single case?

That all obesity must necessarily be because of people eating multiple meals?

Next level is removing most or all carbs from your diet and restricting your eating window to a short time every day, no more than 4 hours. Which is what I do besides longer fasts.

I now don't even need to eat every day -- I had situations where I skipped entire days of eating because I simply forgot about it.

If you think about it most people have hundreds of thousands of calories on them in form of a huge fat layer covering most of the body which is enough for even lean people to live off for weeks at a time. If you think about it, it is pretty silly to complain one is hungry when there is so much energy stored on us.

I remember this thought struck me when I was reading about first Inuits trading in Canadian outposts. They would sell their furs and buy food. When a curious scientist decided to follow them he discovered they would stop outside the outpost, eat ALL food they just bought in one huge binge and then travel back home for many days or even weeks without eating anything. They were not only good at storing fat, but they were also good at recovering the energy when they needed for however long they needed. This is what means to be fat adapted -- being able to completely separate intake of food from burning stored fat for energy.

People nowadays are like a car that does not have a tank for gas. You have to keep pouring the gasoline into the engine constantly or it will shut down. What you want is a large tank from which you can be constantly supplying energy to your engine but you can fill this tank at your convenience.

Causal link requires an investigation to understand what is the nature of the link.

Is it possible that people who are likely to be more obese are also likely to eat garbage food delivered in low quality plastic packaging? And more healthy people are more likely to cook their food from higher quality ingredients like fresh produce that is not delivered in plastic?

See, the above explanation, I think very reasonable (though requiring a proof), could explain why obese people could have higher PFAS?

Another possible explanation (again, I am just sayin', no proof for it): imagine all food is contaminated with PFAS, but obese people have different chemistry that is worse at removing PFAS from their bodies.

This is why we say "correlation does not imply causation". Yes, highly correlated things are interesting and require further investigation. Even if PFAS is not causing obesity we still might learn something interesting about either PFAS or obesity or something else that is connected to both.

It is called fasting. It has been practiced for entirety of human history in all societies except for last couple of decades.

Fasting is an opportunity for the body to burn stored fats. Insulin is a hormone that tells every cell in the body to take sugars from the bloodstream and effectively prevents burning stored fats. When cells are used to burning sugars all the time, when given access to sugars and fats they will chose sugars preferentially. So as long as they have supply of sugar there is very little fat burning happening.

What's more, when you stop eating for a moment, for whatever reason, your body still does not have ability to burn much fat for energy because the metabolic pathways to do it are too dormant to provide enough energy on a moments notice. You become hungry which is your body telling you it can't get energy and you resolve the only way to fix the issue is by putting more carbohydrate-rich food in your mouth.

Fasting periods are necessary for the body to train those metabolic pathways. For example, by eliminating breakfast and not snacking in the evening you can easily double the time it takes between two meals giving couple of hours each day during which your body has to get energy from the fats. Over time your body relearns to burn fats and when you don't eat for a moment for whatever reason it is able to start burning fats faster and start providing more energy lessening the feeling of hunger and immediate need to put more food in your mouth.

Fasting is the normal state of the human body. We have evolved in conditions where food was relatively scarce and when we finally caught something, we had to eat it here and now and then move on and wait until we are able to catch something else at unknown future time.

This means we have evolved to accept food for a relatively short portion of time, be very good at storing energy as fat and then to use this fat for a long time until we could catch something else.

None? There is nothing actionable here.

We already know PFAS are dangerous for other reasons and the war against them is warming up.

And policy is not/should not be made based on just one study. Sadly, there are too many contradicting studies. Things like this need to be re-checked so that policymakers and societies don't waste time chasing things that don't bring any results.

Even then, we need to understand what is magnitude of this effect, what level of PFAS translate to what increase in obesity risk, etc. Then put it in context of already planned PFAS reductions.

Then if I was policymaker I would also look at what are potential projects we are not working on and where are highest return on investments. Just because there is something you can fix doesn't mean you should fix it. There might be another thing with more ROI where you should be spending your efforts.

That is assuming the conclusions of this study are correct, which I don't believe they are.

Again. Missing big fat disclaimer. "Correlation does not imply causation". It is wrong to jump from "Weight loss relapse associated with exposure to perfluoroalkylate substances" to "Obesogenic PFASs may cause weight gain and thus contribute to the obesity pandemic".

Here, the word "may" is correct but it should really be "we just don't know, it is possible". But "obesogenic" suggest that the link has been proven which it has not.

I am not defending PFAS. But our history is full of missed opportunities and billions of people doing stupid shit for decades because somebody jumped to conclusions to fast. We have still not eradicated notion that fats are all wrong and need to be removed from the diet where it is exactly the opposite -- it is very likely that removal of fats from the diet is responsible for the large part of obesity epidemic. Right after people believing you need to eat multiple meals a day to be healthy.

It is important to keep focus on stuff that we already know is detrimental to our health and these are excessive amounts of carbohydrates (filling the void when fats were removed from the diet), refined sugars and reduced time between meals not allowing people to exercise their lipid transport in reverse.

Do you assume engineers who build these things and point cameras at other satellites are unable to plan to make in-focus images?

The thing to remember is that those directions are used for an awful number of things that have nothing to do with the ship moving. Like when you name places for storing things or various pieces of equipment. Changing those names would create a lot of mayhem.

When I captain a boat it is more important for me to communicate things unequivocally. I need to be able to specify what I want to happen, precisely. The crew does not really need to concern themselves with the direction the boat is moving or what is the bigger plan. They just get orders to do specific tasks. Only I (or whoever is responsible for the boat at the moment) really need to understand the context of those tasks although ideally the crew would also understand why they are doing things so that they can anticipate further orders or signal when I make a mistake.

Why this is important is because the plan may sometimes change and then my job is to put a new set of orders and I can't really start by explaining what the new changed plan is or getting any consent.

I was never in a situation like that, but if I was captaining a boat that can change directions, I would still keep stable naming that does not change when the boat stops or changes directions.

Dunno... most people I meet seem to be put off by my software development ideas. I stick to them because they seem to work very well even if it initially creates a lot of friction between me, the team and the management.

Where to start... I think test driven development and unit testing is not giving promised value and instead wastes time and makes software more difficult to refactor and I think functional end to end testing to be much more effective and cost effective. I think code reviews are bad because they don't deliver on promised value and individual craftsmanship (peoples ability to deliver on their own) and pair programming are better. I think microservices to be a wrong approach for 99.9% projects and fixed a bunch of projects by rolling the software into monolyths. I believe bugs can only be truly reduced by taking responsibility for writing correct code in the first place and anything afterwards is expensive and not effective (you can only remove bugs that manifest themselves, everything else stays). I don't compile/run my code multiple times a day -- I write it all in one go, sometimes for weeks, then run it. If it works it means I know what I am doing and if it doesn't -- it is the failure of my process. Where most devs just fix the bug and restart the app I will start an investigation into why my process failed and how I need to fix it -- NTSB-style. I believe that nobody understand what Agile is and the way it is applied is damaging to software industry. I don't believe in linear development progress -- I design my apps top down and at the same time program them bottom up until top down and bottom up meet together. I structure my development process around rewriting the software -- I write the first version and then I will refactor/rewrite to remove any unnecessary complexity until I am happy with it. There is no working software for a long time and then suddenly it is complete. And when it is complete there is no more testing stages, bugs to fix -- it is truly complete.

So you see, I am probably too alien a developer to give advice to general population of developers.

And when I do talk about my ideas it usually ends in flame wars or drowns being downvoted to hell because people tend to downvote anything and everything that does not confirm their existing worldviews.

I don't. There simply isn't any tooling or literature to speak of. I have some experience using control engineering in my electronics projects and that's how I came up with the idea to use it for backend systems. I have researched and developed everything myself. I have used "Modern Control Engineering" by Katsuhiko Ogata, but really, mostly I just learned from the Internet.

My initial motivation was to remove configuration. I have found, historically, that giving people options to configure very complex software more often than not results in problems, especially after original developers leave. More often than not these new people will not understand the implications or interactions between various settings and this will just cause problems. So my aim became to remove any options from the software and make sure it can perform autonomously and recover from wide range of, possibly unknown, situations. Which is exactly what control engineering is about if you think about it!

You know how many systems have "performance" configuration? I use a controller that monitors the state of the system and changes these parameters in real time to regulate system to stay within desired state when the environment of the system changes.

As a very simplified example, imagine a backend service that is being called by external customers and does not control how those customers are calling the service. I can add a delay to each response and I can have even something as simple as PID controller regulate the CPU usage by changing the dalay. Larger delay will usually cause the clients to slow down requests (requests being usually a result of previous request completing). This is simple and naive example but this is more or less what I do.

(Of course, in reality, it is much better to just have a backpressure mechanism and whenever possible you should use one rather than try to work around HTTP inadequacy. But you can't always do it, especially if you have a public API.)

I also typically have lots of other controllers. For example something that regulates memory usage by limiting transactions in flight or something that regulates latency as seen by priority clients or database replication rate/delay, or error rates or a bunch of other parameters.

I also routinely take care of babysitting downstream systems like databases or other APIs. I may have a regulator that will automatically start backing off certain types of traffic as a response to increasing error rates or latencies in a downstream system. All this because those downstream systems are usually shit and not designed to deal with overload and it is easier for me to deal with this proactively than do what everybody else does -- keep bugging those people to fix their issues when their evidently don't know how.

Yep. For example, I use control theory to keep my services at just single percents below maximum throughput achievable on the server. Then I use other tricks (like batching processing) to make the application MORE efficient as the traffic increases.

The end effect is I can just back off 1-5% off the maximum throughput and keep the service there running happily.

I would like to use this occasion to point out that all the discussion about unused CPU is at this time completely pointless.

Most services I have seen waste ORDERS of magnitude by being inefficient. Rather than focusing on trying to saturate the CPU and other resources it is almost always better to just make your application more efficient. That last 30% should be a cherry on top.

> At first thought a moon of a moon didn’t seem to be possible as the gravity of the moon’s planet would certainly make an orbit around a moon unstable.

No, that's not true. Moons can have moons with stable orbits. Not every moon can, though.

If you think about it, the Moon already orbits Earth which orbits Sun.

Our Moon could have satellites but the issue is that it is lumpy. It is not uniform in density and this causes huge gravitational anomalies which prevent long term stable orbits. If Moon was uniform it could have stable orbits.

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