Actually, the electron is not "spinning". When we talk about spin it's an analogy.
The terminology comes from two types of angular momentum in classical physics. One is "orbital" angular momentum, which comes about when an object is moving relative to some other point, like the earth going around the sun. The other kind is "spin" angular momentum, which is the rotation of an object about its centre of mass (like the earth spinning on its axis). The total angular momentum is the sum of these two different kinds.
The whole reason we can talk about the Earth "spinning" is that it has a structure -- it's made of other, smaller things, and the smaller things move around the axis. As far as we know, that isn't true for the electron -- it seems to be a true point particle so far. And yet, it has intrinsic angular momentum, which can be detected experimentally!
In the case of the earth, its spin angular momentum is really just the sum of all the orbital angular momenta of all the little bits of dirt that make it up, orbiting around the axis. Maybe that's true for the electron, and the fact that it has spin is a clue that it's made up of other particles?
Turns out the answer is no. A well known result of quantum mechanics is that any orbital angular momentum (i.e. the usual kind) can only occur in integer multiples of some lowest angular momentum (kind of like how electric charge can only come in multiples of the charge on the electron). If the electron's spin were due to other particles that made up the electron, then its magnitude would be some integer multiple of that unit of angular momentum. Turns out that it's exactly half that lowest value! So it's a different kind of angular momentum altogether, and the electron doesn't really "spin".
Around the time of the last slashdot article about Dvorak, I decided it was worth it to switch. Got my keyboard remapped on boot and took the plunge. It took about a week before I got up to a decent typing speed, and about 2 weeks before it stopped being frustrating to type Dvorak.
One thing I noticed was that even at the very beginning, when typing was maddeningly slow, it just... felt right. When my finger would hit a key, it just felt like that was where the key should be. Hard to explain, really, until you try it.
Of course I also found that QWERTY (man that's weird to type!) is a bit harder to get back into. I bet I'd have trouble typing it because the switch is still so new to me. But people seem to agree that after you start typing QWERTY for a few minutes it comes back to you. Frankly, after getting used to Dvorak, I've never saw the point of using QWERTY for even that long.:)
On your own computer, the best bet is to buy a vinyl CafePress sticker from DVZine. I printed out my own, and it looked awful and the glue melted. The CafePress stickers are a lot better.
I really don't know how well you'll be able to type QWERTY, but like I said I bet if you need to use it it'll come back after 10 minutes or so. That, or you could use a USB keyboard or something.
Methane was detected on the surface of Mars, which could be a sign of living bacteria. It is possible that they could be brought to Earth by probes, resulting in a deadly human plague.
Translation
We should all worry about farting Martian bacteria wiping out the human race as punishment for meddling in the affairs of other planets.
Absolutely.:) Let's see if I can type this by the end of the lecture!
First, figure out the "year number". This part -- and the month number -- take some practice. Here's the first few to get you started:
1900 - 0
1904 - 5
1908 - 3
1912 - 1
1916 - 6
1920 - 4
1924 - 2
1928 - 0
And it repeats thusly. Note that the "year number" starts at 0 for the beginning of the century, and is decreased by two (modulo seven) every leap year.
In case you're interested in the other 75% of the time, simply add one to the year number for every year you add. Thus, 1901 becomes 1, 1902 becomes 2, etc.
The "month" number requires memorization of another table, which cannot be recalculated as quickly as the year number:
Jan - 0
Feb - 3
Mar - 3
Apr - 6
May - 1
Jun - 4
Jul - 6
Aug - 2
Sep - 5
Oct - 0
Nov - 3
Dec - 5
Add the month number to the year number. If your year is a leap year and your month is January or February, subtract 1.
Next, add the day number. The day number is the day.:P
Now, add or subtract sevens as necessary until you end up with a number between 0 and 6:
0 - Sunday
1 - Monday
2 - Tuesday
3 - Wednesday
4 - Thursday
5 - Friday
6 - Saturday
The result will be the day of the week.
If your desired date does not begin with a "19", you have to add a century number as well. I believe 2000 is a leap year, since every 100 years is not but every 400 years is. Thus, the century number of 2000 is 6 (or, equivalently, -1). 1800 is 5, 1700 is 3, etc. (I am not certain of these.)
As an example, today's year number is 5, the month number is 3, and the day number is 24. After compensating for the century by subtracting 1, we obtain 31. This reduces to 3 (by subtracting 28), which corresponds to Wednesday. Since it is Wednesday, and since I am in a large empty room, I further deduce that the lecture has ended.
When I was a kid, my dad lent me a book of Shakuntala Devi's book, "Figuring". She was famous some years ago (in the 50s, I believe) for her own computational ability, multiplying two 13-digit numbers in her head in 28 seconds.
The book itself was an interesting read, and at the time I just ate it up. It has a lot of tricks regarding number theory, mathematical riddles, calendar tricks, and calculation of pi, for example. It teaches how to figure the day of the week for any Gregorian date of any time in a few seconds, a trick which I still remember and use today!
As for the Pi, it contained a few poems and sayings whose letter counts signified the individual digits. I started trying to memorize pi, with my sights set firmly on the world record (as I am not without my own mathematical and mnemonic prowess). However, around grade 9, I decided to abandon my quest in order to get a life. I had memorized 1350 digits at that point.
One such quote held little significance for me at the time, but has since become hilarious. "How I want a drink, alcoholic of course, after the heavy chapters involving quantum mechanics!" Needless to say, my quantum prof found it quite funny.:)
"Not that CBS hasn't been without its problems" should probably read "Not that CBS has been without its problems". Unless, of course, you mean to imply that CBS is the paragon of journalism.;)
Actually, he did attack the church. Instead of keeping his theory within the realm of the scientific, he insisted on telling the church leaders how the relevant passages of Scripture were to be interpreted. The religious do not like being told by the scientific how to read religious texts, just as the scientific detest when the religious tell them how to interpret data. And there is nothing wrong with this.
Things were looking up for Galileo when Pope Urban, a friend of his, ascended to the pontificate. Urban did not subscribe to the new theory, but he was open to considering it, and had dialogue with Galileo concerning the arguments for and against. Inexplicably, Galileo inserted Urban's arguments into the mouth of his character "Simplicio", thereby mocking a friend and potential powerful ally. Needless to say, this did little to help his case.
And his case needed helping indeed. For Galileo was unable to counter the strongest of Aristotle's geocentric arguments: if the earth were in motion, we should observe parallax shifts of the seemingly fixed stars. Either the earth must be stationary, or the stars themselves must be fantastically distant from us, beyond imagination. The equipment necessary to detect these shifts (which we now know to be valid) required a resolution far beyond the means of that day.
Our modern image of the Galileo trial has a beleagured scientist presenting incontrovertible proof to a blinded, tradition-bound institution which will have none of it. In actuality, a brilliant but headstrong man asserted as fact a theory which ran directly counter to the prevailing belief of the day, which he could not prove, and the church did not rush to embrace this new paradigm.
Now, the benefit of retrospect shows us that, although he could not prove his theory, Galileo was indeed mostly right about it. However, the church has also benefited much from hindsight, and has openly acknowledged that it acted wrongly in Galileo's case. They have even issued two stamps in his honour!
None of this is to say or show that the Church was right to condemn Galileo. I merely mean to point out that this famous story is not nearly so one-sided as present historical thought supposes.
They teach those after high school? I only recall insertion sort and a bevy of O(n lg n) sorts.
Actually, I remember one study we did in a first year algorithms class where a bunch of sorts were ranked using averaged actual system times. Bubble sort came in second-last... with the worst sort being a modified Bubble Sort that aimed to improve performance:)
Considering the sheer amount of crap out there -- and, further considering the fact that rehashed mainstream tripe gets top billing -- the odds of me finding what I want there are basically nil.
We're now that much closer to making Space Quest I a reality. Anyone remember that robot at the beginning of the game, when the ship's falling apart? I bet they had that game in mind when they were designing this robot.
Slashdot Mirror
Anybody who has used Linux or any other OS would be aware of the very powerful and feature rich text editor Vi.
The remaining computer users, however, are left in the dark I'm afraid.
I'll just hop into a slow-time warp, and bam!
Actually, the electron is not "spinning". When we talk about spin it's an analogy.
The terminology comes from two types of angular momentum in classical physics. One is "orbital" angular momentum, which comes about when an object is moving relative to some other point, like the earth going around the sun. The other kind is "spin" angular momentum, which is the rotation of an object about its centre of mass (like the earth spinning on its axis). The total angular momentum is the sum of these two different kinds.
The whole reason we can talk about the Earth "spinning" is that it has a structure -- it's made of other, smaller things, and the smaller things move around the axis. As far as we know, that isn't true for the electron -- it seems to be a true point particle so far. And yet, it has intrinsic angular momentum, which can be detected experimentally!
In the case of the earth, its spin angular momentum is really just the sum of all the orbital angular momenta of all the little bits of dirt that make it up, orbiting around the axis. Maybe that's true for the electron, and the fact that it has spin is a clue that it's made up of other particles?
Turns out the answer is no. A well known result of quantum mechanics is that any orbital angular momentum (i.e. the usual kind) can only occur in integer multiples of some lowest angular momentum (kind of like how electric charge can only come in multiples of the charge on the electron). If the electron's spin were due to other particles that made up the electron, then its magnitude would be some integer multiple of that unit of angular momentum. Turns out that it's exactly half that lowest value! So it's a different kind of angular momentum altogether, and the electron doesn't really "spin".
For a sec, I thought they were insulting the astronauts, calling them a bunch of tools who couldn't find their way back to Earth.
One thing I noticed was that even at the very beginning, when typing was maddeningly slow, it just... felt right. When my finger would hit a key, it just felt like that was where the key should be. Hard to explain, really, until you try it.
Of course I also found that QWERTY (man that's weird to type!) is a bit harder to get back into. I bet I'd have trouble typing it because the switch is still so new to me. But people seem to agree that after you start typing QWERTY for a few minutes it comes back to you. Frankly, after getting used to Dvorak, I've never saw the point of using QWERTY for even that long. :)
On your own computer, the best bet is to buy a vinyl CafePress sticker from DVZine. I printed out my own, and it looked awful and the glue melted. The CafePress stickers are a lot better.
I really don't know how well you'll be able to type QWERTY, but like I said I bet if you need to use it it'll come back after 10 minutes or so. That, or you could use a USB keyboard or something.
"Tell me something I don't know! Get out of the way!"
Translation
We should all worry about farting Martian bacteria wiping out the human race as punishment for meddling in the affairs of other planets.
Y'know, when you put it that way...
"Renew! Renew! Renew!"
Sharks get laser beams.
I bet the winner looks pretty funny when the election's over!
First, figure out the "year number". This part -- and the month number -- take some practice. Here's the first few to get you started:
1900 - 0
1904 - 5
1908 - 3
1912 - 1
1916 - 6
1920 - 4
1924 - 2
1928 - 0
And it repeats thusly. Note that the "year number" starts at 0 for the beginning of the century, and is decreased by two (modulo seven) every leap year.
In case you're interested in the other 75% of the time, simply add one to the year number for every year you add. Thus, 1901 becomes 1, 1902 becomes 2, etc.
The "month" number requires memorization of another table, which cannot be recalculated as quickly as the year number:
Jan - 0
Feb - 3
Mar - 3
Apr - 6
May - 1
Jun - 4
Jul - 6
Aug - 2
Sep - 5
Oct - 0
Nov - 3
Dec - 5
Add the month number to the year number. If your year is a leap year and your month is January or February, subtract 1.
Next, add the day number. The day number is the day. :P
Now, add or subtract sevens as necessary until you end up with a number between 0 and 6:
0 - Sunday
1 - Monday
2 - Tuesday
3 - Wednesday
4 - Thursday
5 - Friday
6 - Saturday
The result will be the day of the week.
If your desired date does not begin with a "19", you have to add a century number as well. I believe 2000 is a leap year, since every 100 years is not but every 400 years is. Thus, the century number of 2000 is 6 (or, equivalently, -1). 1800 is 5, 1700 is 3, etc. (I am not certain of these.)
As an example, today's year number is 5, the month number is 3, and the day number is 24. After compensating for the century by subtracting 1, we obtain 31. This reduces to 3 (by subtracting 28), which corresponds to Wednesday. Since it is Wednesday, and since I am in a large empty room, I further deduce that the lecture has ended.
The book itself was an interesting read, and at the time I just ate it up. It has a lot of tricks regarding number theory, mathematical riddles, calendar tricks, and calculation of pi, for example. It teaches how to figure the day of the week for any Gregorian date of any time in a few seconds, a trick which I still remember and use today!
As for the Pi, it contained a few poems and sayings whose letter counts signified the individual digits. I started trying to memorize pi, with my sights set firmly on the world record (as I am not without my own mathematical and mnemonic prowess). However, around grade 9, I decided to abandon my quest in order to get a life. I had memorized 1350 digits at that point.
One such quote held little significance for me at the time, but has since become hilarious. "How I want a drink, alcoholic of course, after the heavy chapters involving quantum mechanics!" Needless to say, my quantum prof found it quite funny. :)
That could have disastrous consequences!
"Not that CBS hasn't been without its problems" should probably read "Not that CBS has been without its problems". Unless, of course, you mean to imply that CBS is the paragon of journalism. ;)
Actually, he did attack the church. Instead of keeping his theory within the realm of the scientific, he insisted on telling the church leaders how the relevant passages of Scripture were to be interpreted. The religious do not like being told by the scientific how to read religious texts, just as the scientific detest when the religious tell them how to interpret data. And there is nothing wrong with this.
Things were looking up for Galileo when Pope Urban, a friend of his, ascended to the pontificate. Urban did not subscribe to the new theory, but he was open to considering it, and had dialogue with Galileo concerning the arguments for and against. Inexplicably, Galileo inserted Urban's arguments into the mouth of his character "Simplicio", thereby mocking a friend and potential powerful ally. Needless to say, this did little to help his case.
And his case needed helping indeed. For Galileo was unable to counter the strongest of Aristotle's geocentric arguments: if the earth were in motion, we should observe parallax shifts of the seemingly fixed stars. Either the earth must be stationary, or the stars themselves must be fantastically distant from us, beyond imagination. The equipment necessary to detect these shifts (which we now know to be valid) required a resolution far beyond the means of that day.
Our modern image of the Galileo trial has a beleagured scientist presenting incontrovertible proof to a blinded, tradition-bound institution which will have none of it. In actuality, a brilliant but headstrong man asserted as fact a theory which ran directly counter to the prevailing belief of the day, which he could not prove, and the church did not rush to embrace this new paradigm.
Now, the benefit of retrospect shows us that, although he could not prove his theory, Galileo was indeed mostly right about it. However, the church has also benefited much from hindsight, and has openly acknowledged that it acted wrongly in Galileo's case. They have even issued two stamps in his honour!
None of this is to say or show that the Church was right to condemn Galileo. I merely mean to point out that this famous story is not nearly so one-sided as present historical thought supposes.
Olds for nerds. Stuff that mattered.
... he'll come on at the start of every movie, and tell the kids to quit downloading his code!
About the football games though, that's interesting. I honestly didn't know if they could tie or not.
...unless... can they tie in football?
... is a network in my, *ahem*, "Personal Area".
What, did it have a beginning?
They teach those after high school? I only recall insertion sort and a bevy of O(n lg n) sorts.
Actually, I remember one study we did in a first year algorithms class where a bunch of sorts were ranked using averaged actual system times. Bubble sort came in second-last... with the worst sort being a modified Bubble Sort that aimed to improve performance :)
Considering the sheer amount of crap out there -- and, further considering the fact that rehashed mainstream tripe gets top billing -- the odds of me finding what I want there are basically nil.
Honestly. I know she's an 8th grader, but it's really not that hard.
We're now that much closer to making Space Quest I a reality. Anyone remember that robot at the beginning of the game, when the ship's falling apart? I bet they had that game in mind when they were designing this robot.