Search found 130 matches

by DavidSh
Tue Sep 18, 2018 3:18 pm UTC
Forum: News & Articles
Topic: The Thread To Remind Me We're Living In The Future
Replies: 1829
Views: 304068

Re: The Thread To Remind Me We're Living In The Future

Do animals have the same antigens as humans though? It appears that apes and old world monkeys have the ABO system of antigens. See http://www.pnas.org/content/109/45/18493 . Important functional parts of the antigens are the same across species, but I can't tell from the paper how much difference ...
by DavidSh
Fri Sep 14, 2018 10:23 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2046: "Trum-"
Replies: 38
Views: 2727

Re: 2046: "Trum-"

I think the Johnson presidents (Andrew and Lyndon) make a better claim for being unrelated than the Roosevelt presidents.
by DavidSh
Fri Aug 31, 2018 10:24 pm UTC
Forum: Mathematics
Topic: random k-sat
Replies: 1
Views: 892

Re: random k-sat

Have you done Monte-Carlo experiments to indicate whether either of your desired results is likely to be true? Also, if you allow for k=1, you can more easily analyze that case. For k=1, the results on the Birthday Problem suggest that if you have on the order of sqrt(n) terms, the chance of having ...
by DavidSh
Wed Aug 29, 2018 2:27 pm UTC
Forum: Mathematics
Topic: "Generalized" polygons?
Replies: 10
Views: 693

Re: "Generalized" polygons?

It's probably better to parse it as "generalized (pentagonal number)" rather than "(generalized pentagon)al number". They seem to be created by taking the formula for pentagonal numbers, and plugging in negative numbers for the length of a side.
by DavidSh
Tue Aug 28, 2018 3:50 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2038: "Hazard Symbol"
Replies: 39
Views: 3228

Re: 2038: "Hazard Symbol"

Soupspoon wrote:There deserves to be a few more portmanteau signs based upon the various ones in the range. And beyond.

I see there is an official warning sign for Guard Dog, but none for Sharks, Alligators, or Octopodes. How do you appropriately placard the moat?
by DavidSh
Mon Aug 27, 2018 5:48 pm UTC
Forum: Mathematics
Topic: multiplication xor
Replies: 2
Views: 498

Re: multiplication xor

There does not exist a, b in {0,1} such that for all s, t in {0,1}, ( (s*t) xor 1) = (s xor a)*(t xor b).
by DavidSh
Fri Aug 24, 2018 9:15 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2037: "Supreme Court Bracket
Replies: 15
Views: 2212

Re: 2037: "Supreme Court Bracket

On the other hand, Dred Scott vs Sanford was a US Supreme Court case, and more well-known than many listed in the bracket. Though I can guess why it wasn't included.
by DavidSh
Fri Aug 24, 2018 2:49 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2037: "Supreme Court Bracket
Replies: 15
Views: 2212

Re: 2037: "Supreme Court Bracket"

⋅ Did the "Virginia is for Lovers" slogan come out after Loving vs. Virginia ? ⋅ Connecticut gets everything west of Narraganset Bay, Massachusetts gets everything in the Bay and east of it, and New York gets Block Island. ⋅ Following the tennis is space prec...
by DavidSh
Mon Aug 20, 2018 10:13 pm UTC
Forum: News & Articles
Topic: In other news... (humorous news items)
Replies: 14874
Views: 2323120

Re: In other news... (humorous news items)

At the end of the article: The escape came less than a week after about 100 goats went on the lam in Idaho, munching their way through a suburban Boise, Idaho, neighborhood in an incident dubbed “Goat-a-Palooza 2018.” The animals were later wrangled onto a truck by the firm We Rent Goats, which app...
by DavidSh
Wed Aug 01, 2018 5:53 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2870
Views: 644092

Re: Miscellaneous Science Questions

Eebster the Great wrote:... because you can't throw a football nearly that far in a vacuum anyway.

That depends on another parameter, the acceleration of gravity. On a suitably sized asteroid, you might be able to throw a football that far. If your suit is sufficiently flexible.
by DavidSh
Tue Jul 31, 2018 2:07 pm UTC
Forum: News & Articles
Topic: The Darker Side of the News
Replies: 4124
Views: 549111

Re: The Darker Side of the News

Mutex wrote:And presumably Russia is only asking for their citizens to be extradited from the US.

Why would you presume that? The Atlantic article mentions Bill Browder, who is a British subject.
by DavidSh
Fri Jul 20, 2018 11:32 am UTC
Forum: News & Articles
Topic: Worldwide CO2 shortage
Replies: 44
Views: 4109

Re: European CO2 shortage

The originally referenced article only talks about a shortage in the UK and mainland Europe. Generating CO2 in other continents won't be very helpful.
by DavidSh
Sat Jul 14, 2018 1:44 pm UTC
Forum: Computer Science
Topic: Help me prove (or disprove) the following problem NP-hard
Replies: 7
Views: 3654

Re: Help me prove (or disprove) the following problem NP-hard

The only formulations I can think along the lines of linear programs also require integrality of the variables, making them integer linear programs. Many NP-hard problems can be formulated as integer linear programs. -- much later -- I think this is NP-hard. I can see an on-line abstract for a paper...
by DavidSh
Thu Jul 12, 2018 7:35 pm UTC
Forum: News & Articles
Topic: Worldwide CO2 shortage
Replies: 44
Views: 4109

Re: Worldwide CO2 shortage

In fact, Guinness has been using nitrogen for decades. Apparently it changes the taste, however.
by DavidSh
Sat Jul 07, 2018 4:01 pm UTC
Forum: News & Articles
Topic: Trump presidency
Replies: 7234
Views: 540358

Re: Trump presidency

Those particular bonds? I'm not sure that's even possible. You would need to know every(or at least a lot) of the specific bonds that China owns right now. Given that the market is liquid, that's an extremely difficult task. It'd be akin to declaring every dollar held by a Texan to be worthless. Ho...
by DavidSh
Fri Jun 29, 2018 1:25 pm UTC
Forum: General
Topic: World Cup 2018!
Replies: 19
Views: 1995

Re: World Cup 2018!

Just as well Swaziland didn't make the tournament.
by DavidSh
Fri Jun 29, 2018 1:14 pm UTC
Forum: News & Articles
Topic: Where Aren't They Now (Obituaries)
Replies: 278
Views: 59347

Re: Where Aren't They Now (Obituaries)

by DavidSh
Tue Jun 12, 2018 9:52 pm UTC
Forum: News & Articles
Topic: In other news... (humorous news items)
Replies: 14874
Views: 2323120

Re: In other news... (humorous news items)

I had always though "Upper Macedonia" was appropriate, but it may be too reminiscent of "Upper Slobbovia". "North Macedonia" works at least as well.
by DavidSh
Wed Jun 06, 2018 8:43 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2003: "Presidential Succession"
Replies: 72
Views: 10041

Re: 2003: "Presidential Succession"

I wonder how many, if any, of those 5753 are natural-born citizens of the United States.
by DavidSh
Tue Jun 05, 2018 9:20 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2002: "LeBron James and Stephen Curry"
Replies: 43
Views: 5635

Re: 2002: "LeBron James and Stephen Curry"

If I recall correctly, 15 degrees of arc on the Earth's surface corresponds to 900 nautical miles. Wikipedia currently says the Magnetic North Pole (location where the magnetic field is vertical) is at 86.5°N 172.6°W, and the Geomagnetic North Pole (north pole of best fit of a magnetic dipole to the...
by DavidSh
Mon Jun 04, 2018 3:54 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 2002: "LeBron James and Stephen Curry"
Replies: 43
Views: 5635

Re: 2002: "LeBron James and Stephen Curry"

What? No Erdos numbers in the calculation? I would be mildly surprised if any active NBA player has a finite Erdos number. On the other hand, I would also be mildly surprised if no active NBA player has a finite Kevin Bacon number. -- And, indeed, Blake Griffin (Detroit Pistons), has a Kevin Bacon ...
by DavidSh
Mon May 14, 2018 2:55 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1993: "Fatal Crash Rate"
Replies: 26
Views: 3984

Re: 1993: Fatal Crash Rate

I suppose, while it is yet unknown how possible it will be to modify self-driving cars to serve as unoccupied tools of murder, the number of fatal car-car crashes a car can be involved in is small, so the impact on the fatal crash rate (of such use) would be negligible.
by DavidSh
Fri May 11, 2018 2:16 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1989: "IMHO"
Replies: 111
Views: 14381

Re: 1989: "IMHO"

I think of DH as Designated Hitter. What were they using it for?
by DavidSh
Tue May 08, 2018 1:00 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1990: "Driving Cars"
Replies: 86
Views: 9464

Re: 1990: "Driving Cars"

Clearly a randomized double-blind trial of the value of driving practice/instruction is called for. The control group would have to have some kind of placebo practice/instruction.
by DavidSh
Mon May 07, 2018 6:40 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1990: "Driving Cars"
Replies: 86
Views: 9464

Re: 1990: "Driving Cars"

If you want to get more scared, 1) there is no minimum age to get an aircraft pilot's license. (for personal use. Becoming a commercial pilot is another story) In the US, all of the FAA-generated certificates I can find have minimum ages. For example, §61.83 Eligibility requirements for student pil...
by DavidSh
Mon May 07, 2018 6:10 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1990: "Driving Cars"
Replies: 86
Views: 9464

Re: 1990: "Driving Cars"

I do suspect that if at the time cars were first invented everybody knew how many injuries and fatalities they would cause, they'd never have been allowed. Somehow it all came upon everybody slowly enough that it's considered acceptable risk to drive now, and of course cars have been getting safer ...
by DavidSh
Fri May 04, 2018 11:07 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1989: "IMHO"
Replies: 111
Views: 14381

Re: 1989: "IMHO"

Not sure why the comic is referencing Three Mile Island. After Chernobyl, people pretty much forgot about TMI.
by DavidSh
Mon Apr 30, 2018 3:27 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1986: "River Border"
Replies: 69
Views: 9782

Re: 1986: River Border

Yes, hello. I do believe that technically a pastry dough must contain shortening, whereas bread dough is made with oil. Pizza is definitely bread. If you fold your slice then it might be a sandwich depending on the hot dog divide. Pizza as I know it, sometimes called "New York pizza", is ...
by DavidSh
Fri Apr 27, 2018 3:59 pm UTC
Forum: Mathematics
Topic: Name of Rounded Triangle
Replies: 8
Views: 2793

Re: Name of Rounded Triangle

Three sets of foci, but six ellipses. Let the rope have length L. Let the poles be A, B, and C, forming a triangle with sides of length d(A,B), d(B,C), d(C,A). Suppose L is only slightly longer than d(A,B)+d(B,C)+d(C,A). The elliptical arc near side AB contains points x such that d(x,A)+d(x,B) = L-(...
by DavidSh
Fri Apr 27, 2018 3:39 pm UTC
Forum: Computer Science
Topic: Formally, What is P and NP?
Replies: 19
Views: 5224

Re: Formally, What is P and NP?

Not quite, no.

The comparison is between what Non-deterministic machines can do in polynomial time and what deterministic machines can do in polynomial time.
by DavidSh
Fri Apr 27, 2018 3:27 pm UTC
Forum: Mathematics
Topic: Name of Rounded Triangle
Replies: 8
Views: 2793

Re: Name of Rounded Triangle

The descriptions of this construction I can find on-line just call it an "Oval", which is a much broader term.
It consists of six elliptical arcs, not three.
by DavidSh
Wed Apr 25, 2018 9:23 pm UTC
Forum: Fictional Science
Topic: Yet another FTL question...
Replies: 35
Views: 6358

Re: Yet another FTL question...

I think the best answer is "nope". Under special relativity, all inertial frames are equivalent. Sure, in your reference frame you measure the clocks in the other reference frame as running slow, but, in the other reference frame they measure the clocks in your reference frame as running s...
by DavidSh
Fri Apr 20, 2018 4:50 pm UTC
Forum: Computer Science
Topic: Formally, What is P and NP?
Replies: 19
Views: 5224

Re: Formally, What is P and NP?

1) Your understanding of NP is incorrect. It is "polynomial-time on a non-deterministic Turing machine", not "non-polynomial". The set of problems in P is a subset of the set of problems in NP. The classic question is, are there any problems in NP that aren't also in P? 2) A typi...
by DavidSh
Mon Apr 16, 2018 9:51 pm UTC
Forum: Mathematics
Topic: Projecting a Polytope
Replies: 5
Views: 1855

Re: Projecting a Polytope

I don't expect this to be easy. After all, if y is of dimension 1 you basically have Linear Programming (finding a maximum or minimum of a linear function over a region defined by linear inequalities), which took quite some time for somebody to find a polynomial-time algorithm for.
by DavidSh
Tue Apr 10, 2018 12:50 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1973: "Star Lore"
Replies: 33
Views: 5941

Re: 1973: "Star Lore"

I had always assumed the theatrical / motion picture "gaffer" as being a dialect form of "grandfather", being used in the sense of "old man". As opposed to the "best boy", his chief assistant. I never actually looked for evidence on this, though.
by DavidSh
Fri Apr 06, 2018 1:48 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1976: "Friendly Questions"
Replies: 35
Views: 5805

Re: 1976: "Friendly Questions"

For a moment I thought scharb was claiming to be over 200 years old.
by DavidSh
Mon Apr 02, 2018 12:44 pm UTC
Forum: Serious Business
Topic: Census Dickery
Replies: 59
Views: 10531

Re: Census Dickery

. The Constitution is actually really clear on that. If it means Citizens, it says Citizens. If it means person, it says Person. All Citizens are Persons, but not all Persons are Citizens. Both are distinct terms with different legal definitions, but the main takeaway is that a person is just some ...
by DavidSh
Sat Mar 31, 2018 1:22 pm UTC
Forum: Hardware
Topic: Thicker Extension Cord = Blown Fuses
Replies: 4
Views: 2666

Re: Thicker Extension Cord = Blown Fuses

What voltage are you using? Power is voltage times current, so if you need to draw 1800 watts at 120 volts, you need 15 amps of current. Adding another 100 watts for the pump pushes you up to nearly 16 amps. If your voltage is below 120 volts, you need more current. If you are working at 220 volts, ...
by DavidSh
Fri Mar 23, 2018 5:13 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1971: "Personal Data"
Replies: 82
Views: 11429

Re: 1971: "Personal Data"

Stargazer71 wrote:So I’m pretty sure that Randall is being sarcastic about the limits of his own knowledge in the second panel ...


I don't think Randall is saying anything at all about his own knowledge in the second panel, even sarcastically,
by DavidSh
Sat Mar 03, 2018 12:09 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1937: "IATA Airport Abbreviations"
Replies: 63
Views: 10365

Re: 1937: "IATA Airport Abbreviations"

Just as well LDY now calls itself the City Of Derry Airport. Londonderry Airport could get confused for London Derry Airport.

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