The 120+ mile range of the gen 2 EV1 (and 4 hour charge time) is admittedly not good for road trips, but it's perfectly good for most commutes.
poor acceleration
You have obviously never driven an EV1. VROOOOOOM!
costlier maintenance
Electric cars are much simpler than ICE cars, so aside from the inevitable glitches of v1.0 of anything, there are far fewer points of failure in an EV. The EV1 doesn't even have a transmission. Admittedly, batteries are expensive and have a finite lifetime, but the same is true for many car parts that EVs lack. It isn't obvious to me that the total maintenance cost should be higher.
weaker car
If by weaker you mean less safe, the EV1 has good stats there. If you mean less power, all I can say is try one and see (but hurry up, before GM crushes them all). VROOOOOM!
If there were a market there, or even one that could be easily developed, the major car manufacturers would have pounced on it (esp. those that are desperate for growth).
Unfortunately, that's not true. First, there is a market. Despite putting essentially no effort (some might say negative effort) into promoting the EV1, GM has always had a long waiting list for the car. They simply never produced enough to meet demand. Now, despite having drivers who like the cars well enough to extend the leases and assume all maintenance costs, or buy them outright, they are taking the cars back and crushing them.
Second, from the perspective of short-term profitablity, it may make sense for car makers to avoid selling EVs even though there is a market for them, since, by selling EVs, they are competing against their own (profitable) product line. On the assumption that someone who does not buy an EV will by an IC car, the most profitable thing to do is not sell EVs until forced to do so by regulation or competition. This does not even require an active conspiracy, just a small enough number of car makers, each doing what maximizes short-term profits.
The American car makers have been doing the very minimum to conform to California law, and give every appearance of sabotaging their own efforts, to create the false impression that there is no demand. The Japanese manufacturers, rather than whining, are selling the cars. Does this remind anyone of the 1980s?
What we have instead is a handful of companies that have made pretty damn impressive efforts...but they are all ultimate failures because there are not enough buyers.
At the risk of sounding like a conspiracy theorist: that's what they want you to think.
We will probably never know what the actual demand for the EV1 was, since GM is not about to tell us how long the waiting lists were, but reports from would-be buyers suggests that the demand was high, and
one survey suggests that as many of 33% of California car buyers are interested in buying EVs.
Take the Amnish, for example. This is a good example of an also-ran of history, a culture that couldn't even exist if it weren't for the protections offered it by much more powerful cultures with dramatically different attitudes and ideals. If an independent Amnish nation had existed at the beginning of the 20th century, is there any doubt in your mind that it would have been completely trampled over the tumultuous century that followed?
Oh, I've never for a moment disagreed with your assertion that attitude toward change is important. GGS just seemed like a less than obvious reference for it, given that other works have placed much more emphasis on culture and Diamond seemed to downplay it. But it has been years since I read GGS, and I will gladly stand corrected if Diamond placed more emphasis on culture than I remembered.
Anyway, good book, eh?
A great book by a great writer. I will never look at an almond (or an acorn) the same way.
Um, I believe the main message of Guns, Germs and Steel is in fact the opposite...
Incorrect. What you describe is indeed a major point of GGS, however there is an entire section on sociological attitudes and technological adaptation. I encourage you to continue your reading where you left off. There's a whole section where the author discusses invention and its relative unimportance next to the cultural readiness to adopt new technology.
I have in fact read GGS from cover to cover, though it was something like five years ago, so I admit my recollection of it may have grown a bit fuzzy. However, a brief scan confirms my statement that what I described was the major point (not just a major point) of the book.
I do, in fact, recall Diamond's discussion of cultural factors, but IIRC, it was mainly to downplay them as inadequate for explaining regional differences in technology development. Within any large region (e.g., a continent), some groups will readily adopt a new technology or resource, and, if others do not, will eventually crush their neighbors. He was not so much arguing that some cultures are resistent to change as arguing that, even if there are such cultures, it makes no difference in the big picture. He also argues empirically that when new resources, such as crops or technology are made available, they are in fact rapidly adopted, contradicting the notion that resistance to change is a significant factor.
An important aspect about some modern cultures (American, Japanese) is the alacrity with which they adopt (and adapt to) new things. Cultures of this type actually tend to dominate the world. Cultures of the opposite type tend to be the also-rans of history, often trodden under heel of the first.
Um, I believe the main message of Guns, Germs and Steel is in fact the opposite: The reason some regions fell behind the curve in technological development is not because they were more resistant to change but because they lacked some necessary precondition, which can ultimately be traced back to factors such as geography and the availability of domesticable plants and animals.
Wonder why it's not eating stars yet, the density there should be high enough for some
motion..
For the same reason that the earth hasn't fallen into the sun yet. From a distance, a black hole is just another gravitational body. Any object orbiting that body is safe, provided it stays well away from the event horizon.
And let's not forget the infrastructure that we all depend on to drive from A to B. Most people seem to think that all those costs are paid for by gas taxes, but that's not true; in the US, at the local level, virtually all road construction and maintenance is paid for by local taxes, such as sales or property tax. Then there's the highway patrol and other services required to keep the freeways running.
While this isn't a subsidy on gas per se, it is a subsidy on driving, which for most vehicles on the road amounts to the same thing. Driving in the US is heavily subsidized, and always has been.
You can't get around
the fact that every battery technology known so far is going to take a loooong time to charge. I could live with having to
stop every 1-1.5 hrs to refuel my car if I knew it was helping the environment (current range limit on EVs). But when it
takes 6-8 hours to recharge, it's an absolute no-go.
Um... how fast do you drive exactly? My GM EV-1 (gen 2) reliably goes 120 miles or more on a charge, and usually takes less than 5 hours to recharge from nearly empty batteries (I don't know what the max recharge time is). Granted, this is not a car to take on road trips, but it's a great commuter car. Plug it in at home, maybe plug it in at work, and smile as you pass gas stations on the way home.
I agree with many of your comments about battery technology, though, especially wrt cold weather.
When I was finishing up grad school, I had to deal with RSI. I tried physical therapy, funky keyboards, dvorak, and, yes, dictation software. I wrote much of my dissertation using dragon dictate, and did some programming with it as well. I had voice macros for common symbols, keywords and emacs commands.
Did it work? Yeah, sort of. For entering normal text, dictation software has gotten to the point that it is definitely usable -- by someone who absolutely can't get by without it (95% accuracy seems really good until you realize it's getting one in 20 words wrong. and your spellchecker won't be any help). But editing programs is harder -- you spend a lot of time making changes to existing text, which is hard to do by voice. After leaving grad school, I gave NaturallySpeaking(TM) a try. I found it better in some ways, worse in others. I think it is far worse for programming than dragon dictate. at least the version i used was (maybe it's been improved), because you could only dictate into a dedicated window, and there was no support for voice macros (IIRC).
So where am I now? Pain-free most of the time. I have flare-ups from time to time and fully accept that this is a lifetime condition. I still use dvorak; it *feels* better, but that's about all I can say.
Since leaving grad school, I spend less time in front of a keyboard, by virtue of spending more time in meetings.:-( That, plus (somewhat) better habits has made a world of difference. I think of RSI as a physical symptom of a psychological condition: compulsiveness. A normal, healthy person does not keep doing something that causes pain. I think the key to dealing with RSI (note: not recovering from -- it's too late for that) is to listen to your body and stop doing things that cause pain. Dictation software might work as a stopgap, but if you don't make a fundamental change in your habits, you'll just end up with a strained voice in addition to your strained wrists.
The designers of C# have admitted the usefulness of genericity, but also confessed that
C# is not going to support genericity on first release. More interestingly, they are
unhappy with C++'s approach to genericity, which is based entirely on templates. It
would be interesting to see what approach C# would take towards the concept, seeing as
templates are pretty much synonymous with genericity at the moment.
As others have pointed out, parametric polymorphism / generic classes are supported elegantly in other languages, such as ML and its variants, without resorting to the hack of templates. But I've only found one post, by an AC, score zero, buried deep in one of the threads (alas, no moderator points) that mentions Generic Java (GJ). GJ provides an elegant solution to adding generics to Java, and may find its way into future Java specs. It essentially works by having the compiler do type checking based on the generic types, but then translate to standard Java by "deleting" the generic parameters and inserting type casts where appropriate. The compiler guarantees that none of those type casts will ever raise an exception. The result is that where C++ templates result in code bloat by producing a copy of the generic class for every concrete instance, the GJ approach yields a single class, but type errors are still caught at compile time as they should be. The rewriting approach also ensures compatability with the JVM, since it compiles down to pure Java (with the addition of a little glue code). The catch is that there is no run-time information about the parameters of generic classes, so explicit runtime type checks (instanceof, etc.) can't be used for parameterized types. There was a nice article about GJ in the Feb 2000 Dr. Dobbs's
I've used GJ quite a bit, and I'm quite happy with it. Furthermore, there's reason to hope that code written in GJ (the syntax of which is similar to C++ templates) will be compatable with future versions of Java, since Sun is looking into adding genericity to Java, and looking at GJ in particular.
there's a really good LaTeX front end called Scientific Workplace, though it's for windoze and it's not free.
there's a really good LaTeX front end called LyX, that runs under Linux, and is free (beer and speech). There's also a version written for KDE, called klyx, which i haven't used.
Well, in the latest literature it has been found that most asteroids above 200m don't rotate faster than a certain amount. The reason appears to be that anything larger than 200m is really just a giant pile of rubble. Rotation above this limit would cause the pile to fall apart.
Yes, that is one of several arguments given for (large) asteroids being rubble piles. The SciAm article also discusses simulation results that predict that large asteroids involved in collisions will tend to turn into rubble piles (fragments fall back together due to gravitational attraction), whereas smaller asteroids will fly apart due to weaker gravitational pull. Observed shapes and densities also tend to support this conjecture but, again, we really need a closer look to know for sure.
Gist of the matter, it would be very hard to shift the direction of an asteroid, let alone one that is only a giant ball of boulders.
Exactly right. Imagine kicking a bean bag chair. Doesn't go anywhere, does it? A rubble-pile asteroid would behave in the same way, absorbing much of the energy of your kick. That doesn't mean moving it is impossible, but it's much harder, and certainly something we should know about well in advance of any attempt to stop a killer asteroid.
Actually, we have a lot to learn about the asteroids. Since they are both small and far away, telescopes can't tell us all that much, and even their basic composition is not well understood.
Why should we care? Well, for one thing, they can tell us a lot about the origins of the solar system. The sun and all the planets are believed to have acreted from a vast cloud of gas and dust. The asteroids could not coalesce into a planet due to the gravitational effects of Jupiter, thus were halted at the planetesimal stage. They can give us insight into the early process of planet formation.
Also, one day one of these suckers could crash into our planet. If we want to have any hope of preventing that, we will need to understand something about their composition. For example, are they solid bodies or are they composed of small rocks held together by gravitational attraction? makes a big difference if we want to try to deflect one heading our way. There is an excellent article in the May issue of Scientific American (no link, since it doesn't seem to be in the online version) that makes a compelling argument for the rubble pile theory.
I'm assuming the operation would halt if and when the second machine generates a problem that the first machine could not solve, thereby proving that it is not conscious (according to Penrose.) If the operation does not halt, then the machine is conscious (according to Penrose.)
That's actually quite a leap, even from the limb that Penrose is out on. First of all, don't conflate the halting problem with the ability to determine whether a specific program halts. To prove that a machine solves the halting problem, you need to prove that it can determine whether any program you feed it will halt.
Furthermore, Penrose argues that human minds are capable of deciding undecidable problems (which TMs are not) and therefore that human minds are not TMs. He does not claim that a machine that could decide undecidable problems would necessarily be conscious. Even if you produced such an impossible machine, there would still be no way of proving that it was conscious, only that it is capable of something TMs are not.
Penrose claims to posess mathematical insights that go beyond computability. I seriously doubt that is the case, but one thing I can state for certain is that I do not. I consider myself a decent programmer but, having been faced with the problem of understanding someone else's spaghetti code (which is quite benign compared to what exists in the space of all possible programs), I am confident that I cannot solve the halting problem in the general case. Having dabbled in mathematics, I am equally certain that I cannot determine whether arbitrary mathematical statements are true or false. Thus, by your statement of Penrose's thesis, I am not conscious. I claim that I am conscious, but by your argument I am not. Now prove I am not.
PS: Yes, I know you are taking a devil's advocate position.
There seems to be process wherein a "genius" in one field of study is automatically elevated to the status of expert in all other fields (cf. Einstein on politics and religion, Pauling on nutrition). I think Penrose's books on AI serve as an excellent warning to those who would avail themselves of this promotion. I have read his books and even attended one of his lectures, and I have great respect for his work in mathematics, but I must say that the theories put forth in ENM and SotM are unsound.
Full disclosure: I am an AI researcher, and I suspect that human-level intelligence is achievable on a Turing-equivalent computer, though I don't expect that to be an easy feat and I am willing to entertain the possibility that I'm wrong.
Among my colleagues (CS PhDs, and not just AI researchers), I don't know a single person who takes Penrose's arguments seriously. There are good arguments that can be raised against AI, but Penrose's are not among them. IMO, all Penrose has succeeded in doing is tarnishing his own reputation.
That said, I don't think anyone has a handle on consciousness (including Dennett, despite having written a book with the bold title "Consciousness Explained"). The inherently subjective nature of consciousness seems to defy scientific investigation. (Say I built a machine that was conscious. How would I know I had succeeded?)
Subsidized? You mean by the gas tax, and personal property tax on cars, and title and tag fees on cars, and (in some places) road tolls, and ticket revnues?
Actually, gas taxes, etc, do not pay all the direct costs of roads you drive on. At the state and national level, they cover most of the direct costs, but adding and maintaining local roads is largely paid for from general taxes.
And that's only looking at direct costs. If you factor in indirect costs, such as traffic cops (I'm not even going to get into environmental costs), then yes, driving is heavily subsidized.
Julian Dibbell wrote an interesting book, My tiny life: crime and passion in a virtual world, in which he talks about gener-bending, cybersex and other such stuff in MUDs -- particularly, LambdaMoo. Most of what's discussed won't be that surprising to/. readers, but I enjoyed reading it.
Back when I was seriously addicted to Nethack, Valkyries were my all-time favorite character class. They're tough, they're neutral, they start out with pretty good stuff, and best of all, they always get Mjolnir first when sacrificing at an alter. And with 25 strength (gauntlets of power), if a Valk throws Mjolnir it will return to her hand, making it an awsome projectile weapon that's also good for hand-to-hand combat.
Game AI developers are struggling to build characters that can survive in tough environments. They're getting better at it. Work in the game AI field is getting to be better than academic AI; the gamers have a real problem and a real market.
As someone who has done some work in game development and more work in "academic AI," (I currently work at NASA, applying AI to space missions), I disagree with this statement. The goal of game developers is to write fun games, with a focus on playability. Developing intelligent adversaries has some value, but a truly intelligent adversary would be no fun to play against because it would always win -- it has the advantage of speed and infinite patience, so it needs to be a little weaker in terms of strategy. Add to this the fact that most computer players cheat (e.g. have access to information a human player doesn't) and the fact that many games consist of a single human against a buttload of AIs, and it becomes clear that the AIs can be as dumb as bricks and still make for a great game. I'm not saying that a lot of clever work doesn't go into designing the AIs, just that it's not the perfect problem domain that one would think. Also, from the game developers I've talked to, I don't get the sense that there's much cutting edge AI research going on, though I'm sure there's some I'm not aware of.
- It will give the defense forces even more justification for their exhorbitant research budget
Umm.. depiction in Hollywood movies not withstanding, NASA is not part of the military.
We have fucked up one planet already. I think we should leave the others alone until we've learned how to be better managers of the environment.
I understand your point, but I don't really agree with it. We should certainly minimize our impact on Mars early on, for the sake of science. It would be nice to know if Mars does now or ever has hosted life, and that will be difficult once it's crawling with Earth life. And if we do find life, we should think long and hard about what to do about it.
However, if Mars is just a lifeless rock, then I think most things we do to it would be an improvement. There's no fragile ecosystem to mess up.
FYI, a variant of Mars Direct is actually being used in NASA's Mars Reference Mission, the plan-in-progress for human exploration of Mars (sorry, no pointer). This is not in any sense a funded program or a final plan, more of an investigation of how it should be done if and when it gets funded.
If the Pilgrims (and the Puritans of the Mass Bay Colony) had brought all the food they needed, nearly half of the population would not have died the first winter. Something to think about, if the colonization of America is to be compared with that of Mars;-)
Yeah, I've always considered Zubrin's pilgrim analogy to be a bit wacky. I'm glad he knows more about space flight than he knows about history. The pilgrims were totally incompetent. By many accounts, they had access to farms and stored food left by native Americans who died from European diseases, and they had access to the knowledge about growing local crops from those who were still alive, and still they almost perished. Because they knew nothing about farming.
I also question comparing "living off the land" in an ecosystem replete with food and breathable air, on a planet we evolved on, to living in a near-airless icebox that certainly has no life more complex than a microbe. Nonetheless, I think Zubrin makes some very good points, and I'm glad we have him as a cheerleader for Mars colonization.
Slashdot Mirror
Second, from the perspective of short-term profitablity, it may make sense for car makers to avoid selling EVs even though there is a market for them, since, by selling EVs, they are competing against their own (profitable) product line. On the assumption that someone who does not buy an EV will by an IC car, the most profitable thing to do is not sell EVs until forced to do so by regulation or competition. This does not even require an active conspiracy, just a small enough number of car makers, each doing what maximizes short-term profits. The American car makers have been doing the very minimum to conform to California law, and give every appearance of sabotaging their own efforts, to create the false impression that there is no demand. The Japanese manufacturers, rather than whining, are selling the cars. Does this remind anyone of the 1980s?
At the risk of sounding like a conspiracy theorist: that's what they want you to think. We will probably never know what the actual demand for the EV1 was, since GM is not about to tell us how long the waiting lists were, but reports from would-be buyers suggests that the demand was high, and one survey suggests that as many of 33% of California car buyers are interested in buying EVs.Oh, I've never for a moment disagreed with your assertion that attitude toward change is important. GGS just seemed like a less than obvious reference for it, given that other works have placed much more emphasis on culture and Diamond seemed to downplay it. But it has been years since I read GGS, and I will gladly stand corrected if Diamond placed more emphasis on culture than I remembered.
A great book by a great writer. I will never look at an almond (or an acorn) the same way.
I have in fact read GGS from cover to cover, though it was something like five years ago, so I admit my recollection of it may have grown a bit fuzzy. However, a brief scan confirms my statement that what I described was the major point (not just a major point) of the book.
I do, in fact, recall Diamond's discussion of cultural factors, but IIRC, it was mainly to downplay them as inadequate for explaining regional differences in technology development. Within any large region (e.g., a continent), some groups will readily adopt a new technology or resource, and, if others do not, will eventually crush their neighbors. He was not so much arguing that some cultures are resistent to change as arguing that, even if there are such cultures, it makes no difference in the big picture. He also argues empirically that when new resources, such as crops or technology are made available, they are in fact rapidly adopted, contradicting the notion that resistance to change is a significant factor.
"i'm . . . mouseman!"
IIRC, many plant species have a large genome, not because of inherent complexity but because of past chromosome doubling.
+1 informative, anyone?
And let's not forget the infrastructure that we all depend on to drive from A to B. Most people seem to think that all those costs are paid for by gas taxes, but that's not true; in the US, at the local level, virtually all road construction and maintenance is paid for by local taxes, such as sales or property tax. Then there's the highway patrol and other services required to keep the freeways running. While this isn't a subsidy on gas per se, it is a subsidy on driving, which for most vehicles on the road amounts to the same thing. Driving in the US is heavily subsidized, and always has been.
I agree with many of your comments about battery technology, though, especially wrt cold weather.
Did it work? Yeah, sort of. For entering normal text, dictation software has gotten to the point that it is definitely usable -- by someone who absolutely can't get by without it (95% accuracy seems really good until you realize it's getting one in 20 words wrong. and your spellchecker won't be any help). But editing programs is harder -- you spend a lot of time making changes to existing text, which is hard to do by voice. After leaving grad school, I gave NaturallySpeaking(TM) a try. I found it better in some ways, worse in others. I think it is far worse for programming than dragon dictate. at least the version i used was (maybe it's been improved), because you could only dictate into a dedicated window, and there was no support for voice macros (IIRC).
So where am I now? Pain-free most of the time. I have flare-ups from time to time and fully accept that this is a lifetime condition. I still use dvorak; it *feels* better, but that's about all I can say. Since leaving grad school, I spend less time in front of a keyboard, by virtue of spending more time in meetings. :-( That, plus (somewhat) better habits has made a world of difference. I think of RSI as a physical symptom of a psychological condition: compulsiveness. A normal, healthy person does not keep doing something that causes pain. I think the key to dealing with RSI (note: not recovering from -- it's too late for that) is to listen to your body and stop doing things that cause pain. Dictation software might work as a stopgap, but if you don't make a fundamental change in your habits, you'll just end up with a strained voice in addition to your strained wrists.
good luck!
I've used GJ quite a bit, and I'm quite happy with it. Furthermore, there's reason to hope that code written in GJ (the syntax of which is similar to C++ templates) will be compatable with future versions of Java, since Sun is looking into adding genericity to Java, and looking at GJ in particular.
Why should we care? Well, for one thing, they can tell us a lot about the origins of the solar system. The sun and all the planets are believed to have acreted from a vast cloud of gas and dust. The asteroids could not coalesce into a planet due to the gravitational effects of Jupiter, thus were halted at the planetesimal stage. They can give us insight into the early process of planet formation.
Also, one day one of these suckers could crash into our planet. If we want to have any hope of preventing that, we will need to understand something about their composition. For example, are they solid bodies or are they composed of small rocks held together by gravitational attraction? makes a big difference if we want to try to deflect one heading our way. There is an excellent article in the May issue of Scientific American (no link, since it doesn't seem to be in the online version) that makes a compelling argument for the rubble pile theory.
Furthermore, Penrose argues that human minds are capable of deciding undecidable problems (which TMs are not) and therefore that human minds are not TMs. He does not claim that a machine that could decide undecidable problems would necessarily be conscious. Even if you produced such an impossible machine, there would still be no way of proving that it was conscious, only that it is capable of something TMs are not.
Penrose claims to posess mathematical insights that go beyond computability. I seriously doubt that is the case, but one thing I can state for certain is that I do not. I consider myself a decent programmer but, having been faced with the problem of understanding someone else's spaghetti code (which is quite benign compared to what exists in the space of all possible programs), I am confident that I cannot solve the halting problem in the general case. Having dabbled in mathematics, I am equally certain that I cannot determine whether arbitrary mathematical statements are true or false. Thus, by your statement of Penrose's thesis, I am not conscious. I claim that I am conscious, but by your argument I am not. Now prove I am not.
PS: Yes, I know you are taking a devil's advocate position.
Full disclosure: I am an AI researcher, and I suspect that human-level intelligence is achievable on a Turing-equivalent computer, though I don't expect that to be an easy feat and I am willing to entertain the possibility that I'm wrong.
Among my colleagues (CS PhDs, and not just AI researchers), I don't know a single person who takes Penrose's arguments seriously. There are good arguments that can be raised against AI, but Penrose's are not among them. IMO, all Penrose has succeeded in doing is tarnishing his own reputation.
That said, I don't think anyone has a handle on consciousness (including Dennett, despite having written a book with the bold title "Consciousness Explained"). The inherently subjective nature of consciousness seems to defy scientific investigation. (Say I built a machine that was conscious. How would I know I had succeeded?)
And that's only looking at direct costs. If you factor in indirect costs, such as traffic cops (I'm not even going to get into environmental costs), then yes, driving is heavily subsidized.
Julian Dibbell wrote an interesting book, My tiny life: crime and passion in a virtual world, in which he talks about gener-bending, cybersex and other such stuff in MUDs -- particularly, LambdaMoo. Most of what's discussed won't be that surprising to /. readers, but I enjoyed reading it.
Back when I was seriously addicted to Nethack, Valkyries were my all-time favorite character class. They're tough, they're neutral, they start out with pretty good stuff, and best of all, they always get Mjolnir first when sacrificing at an alter. And with 25 strength (gauntlets of power), if a Valk throws Mjolnir it will return to her hand, making it an awsome projectile weapon that's also good for hand-to-hand combat.
However, if Mars is just a lifeless rock, then I think most things we do to it would be an improvement. There's no fragile ecosystem to mess up.
FYI, a variant of Mars Direct is actually being used in NASA's Mars Reference Mission, the plan-in-progress for human exploration of Mars (sorry, no pointer). This is not in any sense a funded program or a final plan, more of an investigation of how it should be done if and when it gets funded.
I also question comparing "living off the land" in an ecosystem replete with food and breathable air, on a planet we evolved on, to living in a near-airless icebox that certainly has no life more complex than a microbe. Nonetheless, I think Zubrin makes some very good points, and I'm glad we have him as a cheerleader for Mars colonization.