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mismatchpair

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DNA Computing 8 years ago

You're welcome to do that yourself, if you're so inclined. I doubt they would take your argument seriously though since you're not making any sensible comparisons.

DNA Computing 8 years ago

Currently, DNA may not be a general purpose computing element as the examples you have given, but again this is beside the point you're trying to make, namely, the comparison between the energy efficiency of computation and the energy needed to create the elements which perform the computation. They are not comparable in any sensible way.

DNA Computing 8 years ago

You only have to make DNA once. If you actually wanted to make a sensible comparison, then the question you should be asking is, "How much energy does it take to manufacture a silicon based computing element (such as transistors or CPUs) as opposed to an analogous DNA computing element?" But again, this has no relevance to the computational energy efficiency of the element.

DNA Computing 8 years ago

I think you're confusing the energy efficiency of computation and the energy needed to create the elements which perform the computation. The initial comment refers to the former whereas you're asking about the latter. Your question, "How much energy does it take to chemically synthesize the dNTPs required to do the equivalent of moving a bit..." is not an appropriate analogy because synthesizing dNTPs (energy needed to create computing elements) is not analogous to "moving a bit" (energy needed to perform a computation). It's like comparing how much energy is needed to manufacture a hard disk and how much energy is needed to read/write to and from the hard disk. It's a meaningless comparison.

DNA Computing 8 years ago

Good question. The second law of thermodynamics dictates a theoretical maximum of 3.4 x 10^20 (irreversible) operations per joule (at 300 K or room temperature). I think there is an exemplary work which answers your question. In 1994, Len Adleman (the A in RSA) wrote a Science paper[0] where he used DNA to solve a directed Hamiltonian path problem. In that work, he calculated that in principle 1 joule is sufficient for ~2 x 10^19 operations using DNA. This number is remarkable in that it is extremely close to the theoretical maximum. Existing supercomputers (at the time the paper was written) execute at most 10^9 operations per joule. He goes on to say that "the energy consumed during other parts of the molecular computation, such as oligonucleotide synthesis and PCR, should also be small in comparison to that consumed by current supercomputers".

[0] L. Adleman, "Molecular Computation of Solutions to Combinatorial Problems", Science 266, 1022 (1994)

DNA Computing 8 years ago

This was the first paper to experimentally demonstrate the use double-crossover (DX) DNA tiles to implement a 1D cellular automata, namely Sierpinski patterns. Hence, a new type of crystal, called algorithmic crystals were born. Here the error rate was between 1% to 10%. In a subsequent work in collaboration with Erik Winfree, we're trying to reduce the error rate of these types of DNA computation models.

DNA Computing 8 years ago

I work in the field (DNA nanotechnology) and a question I often get asked is, "When are DNA computers going to replace silicon based computers?" The answer is that that's highly unlikely to happen. They both have their strengths and drawbacks and their own domains. For instance, DNA computing will probably never match the computation speed of silicon based computing since in order for DNA to compute,chemical reactions such as DNA hybridization or dissociation with their complementary counterparts must occur (which is very slow compared to manipulating electron flow). Also, the error rate using DNA is pretty high, e.g., for DNA computing using double-crossover tiles (which is mathematically equivalent to Turing-universal Wang tiles) implementing an XOR logic cellular automata, the best error rate is currently roughly on the order of ~0.1%. Two of the greatest strengths of DNA computation are its energy efficiency and massive parallelism. A microtube containing just 100 ul of DNA solution can have roughly 10^17 or 10^18 strands of DNA working in parallel. Lastly, it may be easier to get computing DNA nanomachines to work /in vivo/ or inside cells as opposed to silicon based nanomachines.

Before Suneung, there were equally, if not more, grueling college entrance exams. I think the point the commentor is trying to make is that this type of education has been the fuel for Korea's social and economic rise.

Below is problem 33 of this year's English exam. For the English section of the exam, there are a total of 45 questions; 17 listening comprehension (around 25 minutes) and 28 reading comprehension questions (around 45 minutes). Imagine yourself (if you're non-Korean) trying to comprehend something like this in a completely foreign language.

33. Heritage is concerned with the ways in which very selective material artefacts, mythologies, memories and traditions become resources for the present. The contents, interpretations and representations of the resource are selected according to the demands of the present; an imagined past provides resources for a heritage that is to be passed onto an imagined future. It follows too that the meanings and functions of memory and tradition are defined in the present. Further, heritage is more concerned with meanings than material artefacts. It is the former that give value, either cultural or financial, to the latter and explain why they have been selected from the near infinity of the past. In turn, they may later be discarded as the demands of present societies change, or even, as is presently occurring in the former Eastern Europe, when pasts have to be reinvented to reflect new presents. Thus heritage is __________________. [3 points]

① about preserving universal cultural values

② a mirror reflecting the artefacts of the past

③ neither concerned with the present nor the future

④ as much about forgetting as remembering the past

⑤ a collection of memories and traditions of a society

Yes, you're right. The self-assembly of the nanorobot is done using the same technique as in the video you linked. In fact, the speaker in the video, Paul Rothemund, is the person who first engineered this self-assembly technique called DNA origami. In his cover article in Nature (2006), where it was first published, you can get a sense of how intricate the folding technique is just by looking at the cover picture of the smiley face he made using DNA (http://www.nature.com/nature/journal/v440/n7082/index.html, the diameter of the smiley face shown here is roughly 100 nm wide).

No, there is no way to control it externally, nor does it have a mechanism for active movement. The DNA nanorobots move passively along with the blood flow and latches onto the tumors through their apatmer binding sites.

Yes, you're right. There was a high level of commitment by the overwhelming majority of the population (~80% of the population was in favor of impeachment vs ~12% against), but the reason people kept showing up weekend after weekend for the demonstrations was due to a lack of faith in all three branches of government, i.e. it was to keep public pressure on the legislative, judicial, and to a lesser extent the executive branches. The day the most people showed up (2.32 million, Dec. 3rd, 2016) was the week before the parliament passed the impeachment bill. People really wanted to express their determination and anger as even some opposition party members were balking at the idea of impeaching the president (we have 300 members of parliament, 200 votes were needed for the bill to pass, and 234 voted in favor).

Do you know if anything will be done or can be done to prevent that from happening again?

My understanding is that in a democratic system, there is always the risk of putting someone like Park (or a more dramatic example is Hitler) in power. A sign of a well-functioning democracy is whether appropriate social mechanisms exist so that people can freely exercise the power to take back and undo what they think is a mistake. I think history shows the only thing that works to prevent these kinds of mistakes is an informed public, educating the masses, and taking an active role (however small) in social and political matters.

How crooked is the system on Korea compared with the US?

During the past 10 years in Korea (which was under a conservative government), transparency indices dropped dramatically across the board, e.g. social, financial, political, freedom of press. Transparency International (http://www.transparency.org/) puts out a report every year on government corruption, and in 2016 Korea placed 52nd out of 176 countries (out of the 35 OECD countries Korea placed 29th). For comparison, the US placed 18th and the UK 10th out of 176 countries (Denmark and New Zealand tied for the top spot for being the least corrupt).

The charges ex-president Park faced in the impeachment trial (held in the constitutional court) are different than what she will now be facing in a criminal court. The constitutional court confirmed charges of extortion, abuse of power, and leaking government secrets, which were the basis for upholding the impeachment. Now, having been forced from power and no longer enjoying immunity, the criminal court will decide whether she's criminally guilty of these charges as well as bribery charges from Samsung, Hyundai, SK, Lotte, etc. which carries a minimum of 10 years to a maximum sentence of life in prison.

Hi, I'm a native of Seoul and have attended most of the anti-Park government candlelight rallies held every Saturday for the past 20 weeks in Seoul. A total of over 15 million people have attended these nationwide protests during this time with a single day record of 2.32 million people in attendance on Dec. 3rd, 2016. All of these civil protests have been peaceful without any incidents of violence, vandalism, looting, or even littering. Just ordinary people wanting a corrupt government to be outed, the court system to do its due diligence, and chaebols (Samsung, SK, Lotte, etc.) to be persecuted for cronyism with the government. You get a real feeling of solidarity just being among the people. Take a look at this exhilarating video - https://www.youtube.com/watch?v=3fC9lhyzjDI - people doing a candlelight wave in one of the protests held in downtown Seoul. I'll be online all day today, so feel free to ask me questions about any of this or the current political situation in Korea.