HNHacker News
TopNewBestAskShowJobs

dschleef

52 karma · joined March 6, 2012

submissionscomments
dschleef··on Why the weak nuclear force is short range
This article goes to great contortions to avoid talking about electroweak theory or spontaneous symmetry breaking, both of which have decent Wikipedia articles, and are crucial to understanding what's going on here. Spontaneous symmetry breaking of the electroweak interaction and the Higgs mechanism is the reason _why_ the W and Z have mass. The article throws up a "who knows?" at this. When you write down the field equations for a massive boson field, you get an additional m^2 term in the denominator of the propagator, which contributes a e^(-r/m) term to the interaction force at low energy, such as the decay of a neutron or a weak-mediated nuclear decay.

Is there an ELI5 version of this? I think the article tries, and it's always cool to see physics described from a different vantage point.

My ELI5 version would be: fields with a massive gauge boson are "dragged down" in energy by the mass of the boson, so interactions propagate as if they have negative energy. What does a negative energy wave propagation look like? Similar negative energy wave propagations in physics are evanescent waves and electron tunneling, both of which have exponential drop-off terms, so it makes sense to see an exponential factor in massive boson interactions.

dschleef··on Ask HN: Why are non-technical managers paid more than engineers?
> There's often a lifetime of work behind the development of that skill.

This is literally true of every senior job role.

It seems like it's mostly software engineers that don't get this.

dschleef··on MtGox's Bitcoin price drops to $260 (others at $600+)
Or, people are realizing that there might not be enough actual BTC to back all those MtGoxBTC.
dschleef··on Sushinomics: How Bluefin Tuna Became a Million-Dollar Fish
It's hilarious that people believe there was an actual, unstaged market transaction selling a fish for $3k/pound.
dschleef··on Requirements for DRM in HTML are confidential
Compliance rules for Microsoft Playready: http://www.microsoft.com/playready/licensing/compliance/

The encryption part of DRM systems is effectively the same as client-side SSL certificates with a secret SSL certificate. How well it's kept secret is defined in the compliance documents. This secret, plus a secure decoding and output path, are the engineering core of DRM systems.

Studios require "industry standard DRM" for movies and TV shows, with lesser requirements for SD. This effectively means "DRM backed by some entity with lots of money that we can sue if things go wrong". Studios approve each individual device that you serve to, usually with compliance targets at some particular future date for various existing loopholes.

Flash (Adobe Access) is somewhat different, and has an obfuscated method for generating the equivalent of a client cert, thus on laptops it's only rated for SD by most (all?) studios. Apparently studios don't care too much about people copying SD content.

Studios would theoretically approve watermarking DRM systems, but there are two major barriers: having a large (ahem, suable) company offering it, and some way to serve individualized media through a CDN. Neither seem likely. So nobody loses too much sleep about whether studios would actually approve watermarking.

dschleef··on Scientific Breakthrough Lets SnappyCam App Take 20 Full-Res Photos Per Second
This kind of functionality is standard on OMAP4 devices.
dschleef··on Why current social technologies might be keeping us from truly connecting
This link is an artificial construct designed to provide the superficial result of a real article.
dschleef··on Where are the Voyagers?
86400s is one day, not one year.
dschleef··on How clothes should fit
Fat shaming in the first sentence.
dschleef··on There are no 10x developers, but there are 1/10 ones
Is a 10x developer the same as a "10 star" developer?
dschleef··on Texas Instruments Cuts 1,700 Jobs and Winds Down Tablet Chips
Not directly. Davinci is a different business unit than OMAP.
dschleef··on U.S. Arrests Paul Ceglia for Multi-Billion Dollar Scheme to Defraud Facebook
nimius illectus - "the excessive amount that is unread"
dschleef··on Microsoft: Shortage of tech workers in the US becoming 'genuine crisis'
I will care about companies complaining about too few H1B visas when they start paying equivalent H1B visa holders and citizens the same.
dschleef··on Atomic bond types discernible in images
The tip atom would be oxygen, as CO adsorbs to metal surfaces via carbon-metal bonding.
dschleef··on Gen X Hits Another Bump in the Road
The author appears to either not know how old Gen-Xer's are, or is smoking crack. We entered the job market during the 90's boom, so we were much better employed in our early careers compared to today's grads. We've never had jobs that had pensions, and have been told our entire lives to save for retirement, so we won't "lose" our pensions. The housing boom/bust affected all ages. And we're not quite old enough to suffer from recession-induced early retirement. Nor are we currently retiring and moving our savings into fixed-income investments with historically low rates. I'd say Gen-X has done well in the Great Recession, comparatively.

EDIT: I reread the article replacing "Gen-X" with "youngin's", and it makes a lot more sense. Also, we were the last generation that could reasonably work their way through college without loans.

dschleef··on Sugar 50x more potent than total calories in explaining diabetes [video]
Meh. I generally assume people have good motives, unless proven otherwise. Lustig is screaming "the sky is falling!" Feinman is responding in a perfectly natural fashion, "If they sky were falling, we would have noticed by now."
dschleef··on Sugar 50x more potent than total calories in explaining diabetes [video]
Lustig's premise (from this and other sources) is essentially: (translated for a techie audience)

1. There is a clean pathway and dirty pathway for converting fructose to glycogen in the liver. The clean pathway is easily overloaded by consuming a lot of fructose at once. ("A lot" being more than 12 oz of soda, roughly.) The key bit is that the bad effects are non-linear.

2. The dirty pathway produces metabolites that cause the body's metabolism to switch to an imbalanced state, which if not corrected, leads to metabolic syndrome and type-II diabetes.

3. The dirty pathway is similar to alcohol consumption, with similar long-term effects. This is why he calls fructose a poison.

4. Dietary fiber slows down absorbtion of fructose, thus giving the liver more time to process fructose using the clean pathway. So an apple (fiber!) causes less of a fructose overload problem than a similar quantity of apple juice.

From this, Lustig hypothesises that metabolic syndrome is primarily caused by overconsumption of fructose, and that a diet that has low or zero fructose and high in fiber will correct metabolic syndrome. This is a testable hypothesis, and should be relatively easy to test, even by individuals.

My added notes:

1. There's lots of talk about "sugar", which is dumb, because "sugar" means different things to different people. Lustig means "fructose", which is present in sugar, HFCS, agave nectar, honey, all sweet fruits, fruit juices, etc.

2. Everyone's body, lifestyle, eating habits, exercise habits, and metabolic syndrome level is different, thus everyone will respond to fructose (and indeed any food) differently. If you care, learn how food works in your body and create a diet that fits your needs. And especially, don't extrapolate from your own experience to all people.

3. Several fad diets of recent years fit rather neatly into Lustig's recommendation, including Atkins, South Beach, mediterranean, raw vegan. If you care, find one that works for you.

dschleef··on Sugar 50x more potent than total calories in explaining diabetes [video]
They are technically both correct, but in different situations. If you drink a glass of orange juice, you get Feinman's case and no problems. If you drink a 72 oz soda, you get Lustig's case. Lustig goes into details about the differences in other videos, and makes the point that the 72-oz soda case is very common in America.
dschleef··on The Crisis in American Walking
5 seconds of Googling indicates that you're making shit up:

http://www-fars.nhtsa.dot.gov/Main/index.aspx

The second half is, of course, completely correct.

(Edit: please read "making shit up" as "your source is inaccurate")

dschleef··on Should We Use Progressive JPEGs for Retina Displays?
A simpler explanation would be that baseline JPEG is decoded in hardware that has a maximum width of 2048 or 4096, and progressive JPEG triggers a software fallback. Easy for Apple to fix, just add a check for widths larger than the hardware can handle.