The SEC will never bring charges against any Big Bank. Not now against Goldman Sachs, or ever.
A quick recap:
The Senate’s Permanent Subcommittee on Investigations found that Goldman Sachs “designed, marketed, and sold CDOs in ways that created conflicts of interest with the firm’s clients and at times led to the bank’s profiting from the same products that caused substantial losses for its clients.”
[Senator Carl] Levin gift-wrapped the whole thing for [Attorney General Eric Holder] He could have had a dozen easy convictions just on the evidence in that report, and if he had been creative, if he had used his vast power to roll up the guilty and flip them into more revelations, then he’d have had enough cases to last the AG’s office the next decade. But the Holders of the world do not want to be creative when the targets are politically influential rich people. Instead, they use their creativity against Roger Clemens, Barry Bonds, immigrant housekeepers, and guys who knock over liquor stores.
So that’s it. Big Banks will never be charged with anything because of two simple facts:
They can afford the best lawyers in the world and no one wants to look stupid against them
Government agencies don’t want to upset well-connected rich people
I received termination papers from my employer on Friday. It made me a little bit sad. Not because I’ll miss the place — I hated my job — but because I had gone in with such high hopes.
For the first month or two, I was the first one in the office every morning, bright-eyed and bushy-tailed. I thought that if I pretended hard enough to love my job, it would become reality. I remember the moment my imaginary world came crashing down.
I had been assigned to conduct physical synthesis trials with my coworker Brian. This is a task that involves running a script and squinting at numbers, maybe rerunning parts of the script if the numbers didn’t look right. Brian was walking me through the protocol, but I kept skipping steps and rushing through the output. This frustrated him.
“What’s your hurry??”
“I want to get this sizing stuff done so that we can move on to the FUN stuff!”
“What fun stuff? When we finish this, we’ll just have more cells to do.”
“And after we finish those, then we get to do something more interesting?”
“Then we do this for the rest of the chip until it tapes out next year.”
“What the HELL? When do we get to the fun stuff?”
“There is no fun stuff. It’s a job.”
A job. He sounded like my mother. Jobs aren’t supposed to be fun. Brian is a Chinese immigrant, just like my mom. They came to this country to work hard at soul-sucking jobs so that they could provide their children with the opportunity to — do what?? Grow up and get unfulfilling careers of their own? Pass this misery on for generations?
If I wanted to sell my soul for a six-figure salary, I would have become a prostitute. At least the hours are flexible.
Cellular computing has been explored on a number of levels. I’ll start with one that is most analogous to CMOS circuits.
DNA as a transistor
DNA is a double-stranded structure, each strand a polymer consisting of a series of nucleobases, or bases. There are four bases: guanine (G), cytosine (C), adenine (A), thymine (T). G binds with C and A binds with T, all via hydrogen bonds, and that’s how the double helix is formed.
Logic functions are performed using different concentrations of single- and double- stranded DNA structures. Signals are measured by their relative quantities.
A single gate takes the form of a double-stranded complex, with a short exposed end, called the toehold. An input signal is a strand of DNA with a sequence corresponding to the toehold of the logic gate. This input then binds to the toehold and displaces the original anti-parallel strand, which becomes the output.
The input signal binds to the toehold on the logic gate. The adjacent strand on the logic gate gets bumped off and becomes the output signal.
This mechanism is called branch displacement. The kinetic energy of a loose DNA strand flopping around is enough to break the hydrogen bonds of the original base pairs.
Often, there are far fewer input signals than logic gates. Something called “fuel” is added to the medium to catalyze the displacement actions.
The “fuel” strand binds to the toehold that the output left behind. It bumps the input signal off through the same branch displacement mechanism. The input is then free to go displace another output signal.
The “fuel” displaces an input signal bound to the original logic gate. The input is then free to go displace another output signal.
Of course, the output strand can turn around and bump the input back off, reversing the reaction. However, the output strand cannot displace the “fuel”, because the “fuel” occupies the same toehold that the output signal uses.
Finally, in order to truly emulate a transistor switch, a threshold complex is introduced. Threshold complexes bind to the input signals and block them from binding to the gate. The input signal concentration must exceed that of the threshold in order to generate an output signal.
The input binds to the threshold complex and becomes trapped.
And that is how a DNA transistor works!
Logic Gates
Signals are encoded using dual-rail logic, where a bit is represented using two wires. A ‘1’ is indicated by the presence of one signal strand, and ‘0’ is the presence of the other. The absence of either signals indicates that data are not yet ready. This is also commonly used in asynchronous circuits, where clock signals aren’t available to indicate when data are valid. Molecular computing is, after all, asynchronous.
With dual-rail logic, an inverter is simply the process of switching the names of the ‘0’ and ‘1’ signals.
For the OR function, two input signals feed into a gate complex with no threshold and no fuel. The output feeds into a rectifier with a low enough threshold that the presence of only one of the input strands can generate an output signal.
For an AND gate, the rectifier threshold is increased so that both input signals must be present to generate sufficient output.
Obviously, these gates generate only the ‘1’ rail of the output. Dual-rail logic requires the ‘0’ rail be generated as well, using an inverted AND function to generate OR.0 and an inverted OR gate to generate AND.0.
OR gate: Rectified output w4,5 generated from a lower threshold. AND gate: Rectified output w4,5 generated from a higher threshold
Tenacity is the ability to fall down 7 times and get up 8. Nana korobi ya oki, as Kathy would say. Acknowledge the mistake and move on. If I were to flop over and accept a dead-end job as my career fate, then that would be giving up.
