From http://newscenter.berkeley.edu/2013/06/04/roman-concrete/
While Roman concrete is durable, Monteiro said it is unlikely to replace modern concrete because it is not ideal for construction where faster hardening is needed.
But the researchers are now finding ways to apply their discoveries about Roman concrete to the development of more earth-friendly and durable modern concrete. They are investigating whether volcanic ash would be a good, large-volume substitute in countries without easy access to fly ash, an industrial waste product from the burning of coal that is commonly used to produce modern, green concrete.
“There is not enough fly ash in this world to replace half of the Portland cement being used,” said Monteiro. “Many countries don’t have fly ash, so the idea is to find alternative, local materials that will work, including the kind of volcanic ash that Romans used. Using these alternatives could replace 40 percent of the world’s demand for Portland cement.”
The discovery of how genes actually influence human behaviour, and how human behaviour influences genes, is about to recast the debate entirely. No longer is it nature versus nurture, but nature via nurture. Genes are designed to take their cues from nurture
Replace human for bee or for organism and I think the quote still stands.
It is not that the behaviour of an organism is for the most part determined by it genes, or either that is is determined by it nurture.
Nurture will give direction, Nature will limit the abilities.
How much you'll train a dog, it will never be able to play chess. How much you'll train a toddler, it will never be able to have capabilities to follow a scent trail like a bloodhound.
And what about reproducibility?. It would be rather hard too say "Oh yeah, I confirmed that experiment in my laboratory". If something would be wrong wired and thereby giving some false positives, how do you test for those? They must have some redundant checking mechanism somewhere...
This would imply that for a certain software product the US version would cost less than a localized version. A quick look tweakers price watch seems to confirm this. If you look at this page you see that the US Int. version for Microsoft Office PowerPoint 2007 costs 113,18 euro whereas the dutch version costs 240,30 euro. I know, statistically "one" means "none" and I'm not sure what the "US Int." means. Are there any other examples where the non localized version is cheaper than the localized version for the same software product?
Well... some biologist do have a problem with the Bdelloid rotifers.
John Maynard Smith, not a small thinker among biologist, called these creatures "An Evolutionary Scandal".
It is true that bacteria produce asexuall, but they still exchange genetic material using conjugation.
For instance, existing Windows 3.1 public terminals used a program called Deepfreeze that rebooted the system at the end of each session, something that had to be re-engineered for Linux
Could someone enlighten me why this program "Deepfreeze" was needed in the first place. And why this behaviour should be replicated in linux?
probably not... viruses are often host specific. They have to attach to specific receptors to enter the cell. So as long as the bacteria in our digestive tract do not share the surface proteins with Listeria, the bacteriophage will only tarcet Listeria.
Since the kernel is the interface to the hardware, it would be more precise to say that they both have the same motor and wheels etc, but are laid out with a different dashboard, steering wheels, gears (?), turbo and all other things that are between the driver and the hardware of the car (whatever that might be)
I often write notes in my books with a pencile, but it can be very cumbersome to erase those notes (especially on low quality paperbacks).
It would be nice if you could scribble something and the reader would save it to a separate file, so the reader would only have to overlay the notes over the pdf. One could even exchange notes etc. to produce annotated books.
Ada is named after Ada Byron (Lady Lovelace)... But it definitely did not attract a lot of eager yound males Maybe they should have named it Britney or something
I do not think that hardware will be the best the best discriminator for choosing the best distro. I think (but I could be wrong) that your experience with linux would be a better indicator for the kind of distro you want. If you have little experience with linux I would go for mandrake (or something other very userfriendly distro). If you want to squeeze all the performance from your hardware go for linux-from-scratch (and as a bonus learn an awfull lot in the process).
I would say that most distro should perform about the same without tweaking.
Probably the most perceived performance difference will be in the window mananger you will install. (eg BlackBox(light) -> WindowMaker (some what heavier) -> KDE (heavy))
Re:freezing water
on
How Ice Melts
·
· Score: 5, Informative
It is called the Mpemba Effect.
More on this phenomenon (history en possible explanations) here
(S + C + W + N) / B<br> Ooohh that is way to simple... *Real* formulas have at least one sinus function, pi should be involved somewhere and to give it that real scientific look, sigma and unknown variables
So i gave you function a bit of pepper:
e-1 x -- S + sin(C) + w N \ ______________________ / -- pi * B
Which is better, a clock that is right only once a year, or a clock that is right twice every day?
'The latter,' you reply, '"unquestionably.' Very good, now attend.
I have two clocks: one doesn't go at all, and the other loses a minute a day: which would you prefer? 'The losing one,' you answer, 'without a doubt.' Now observe: the one which loses a minute a day has to lose twelve hours, or seven hundred and twenty minutes before it is right again, consequently it is only right once in two years, whereas the other is evidently right as often as the time it points to comes round, which happens twice a day.
So you've contradicted yourself once.
'Ah, but,' you say, 'what's the use of its being right twice a day, if I can't tell when the time comes?' Why, suppose the clock points to eight o'clock, don't you see that the clock is right at eight o'clock? Consequently, when eight o'clock comes round your clock is right.
'Yes, I see that,' you reply.
Very good, then you've contradicted yourself twice: now get out of the difficulty as best you can, and don't contradict yourself again if you can help it.
You might go on to ask, 'How am I to know when eight o'clock does come? My clock will not tell me.' Be patient: you know that when eight o'clock comes your clock is right, very good; then your rule is this: keep your eye fixed on your clock, and the very moment it is right it will be eight o'clock. 'But--,' you say. There, that'll do; the more you argue the farther you get from the point, so it will be as well to stop.
Lewis Carroll: ca. 1850 In: The Rectory Umbrella, M.S. First published 1898.
source
Single organisms aren't of ultimate importance to evolution.
There is no importance in evolution. It is simple algortihm.
It just happens.
Futhermore species do not replicate. Organisms do.
To be even more precise genes do. Therefore the level of selection is the gene (or organism if you prefer... doesn't matter).
That's why we give up half of our DNA when we mate. The group surviving trumps any single organism within the group surviving.
Here you touch a very senstive topic for biologist.
Like young boys, biologist get nervous if you start talking about sex. Why? The reason is simple:
Biologist do not really understand sex.
Giving up half your genes! It must be compensated by something really big!
Some hypothesis do exist. But the do not really involve group selection.
Some candidates are:
The Lottery Principle (don't bet on 1 horse)
Muller's Ratchet (deleterious mutations)
Fisher-Muller Hypothesis (? forgot)
Tangled Bank (Be prepared)
Red Queen (arms race with pathogenes)
The DNA Repair Hypothesis (be fresh)
Until now the best candidate is The Red Queen.
If you are interested in the origin of sex...
Google is good info as well....
In biology death is not really seen as a "function" of life.
It is indeed an effect of limited environmental resources. But not in the way you just described it.
Evolution is not about species but about individuals (or better put about replication and survival of information by means of selection).
Suppose in a population two kind of types exists. One type tries repairs itself whenever anything breaksdown. This will cost (a lot of) resources.
Another species has a different strategy. It puts some of its resources in offspring and some in maintenance.
Which type would increase in the population?
If we would bend this analogy to daily life it would be something like this:
You have a limited amount of income. You need a car for transportation.
What would you do?
1) Always repair your car (whatever dent or scratch) or 2) only invest in crucial maintenance and replace it after x years with a new car, when maintenance gets too expensive?
As you might have guessed, organisms go for option 2, it costs less.
The ones that would go for option 1 would have to compete all the time with type 2 and the offspring of the types of 2. Type 2 will win.
A side effect is that reproductive organs are not repaired all the time. Therefore selection stops for an individual after its reproductive age. The rest is evolutionary free lunch (for better or worse).
If a gene would exist that would give an organism a reproductive advantage in the beginning of its life, but would give a stong detrimental effect after its reproductive age (death, for example), it would be still favoured by natural selection.
Therefore death is a simple outcome of a cost/benefit analysis. Immortality is simple too expensive.
Probably RNA came first.. It is less stable than DNA but is has shown to be able of enzymatic activity. RNA is still used as a katalytic agent in cells (rRNA for example). It therefore possess two very import biologic attributes: it can hold information and it can influence its environment by means of katalysis.
So it could be the ultimate first replicator.
It was a very popular hypothesis (don't know if it still is) that life started with RNA (google for "RNA world" or something)
It think it is moslty due to the nature of the language.
If a project gets complex, and you don't have a compiler to check your code before it runs, refactoring gets really difficult. You can still do some sort of unit testing. But the combination of unit testing and strong type language is much more powerfull.
If refactoring gets difficult and adjustments have to be implimented due to requirement changes, bugs will start to appear. And they will only rear their heads once the code is executed.
A class might still pass the unit test but without interface checking of a compiler you are never certain that other code using that class will not fail.
I could be doing something wrong but often when I have to change code in php I use grep to check whether other code is using that function etc.
Slashdot Mirror
From http://newscenter.berkeley.edu/2013/06/04/roman-concrete/ While Roman concrete is durable, Monteiro said it is unlikely to replace modern concrete because it is not ideal for construction where faster hardening is needed. But the researchers are now finding ways to apply their discoveries about Roman concrete to the development of more earth-friendly and durable modern concrete. They are investigating whether volcanic ash would be a good, large-volume substitute in countries without easy access to fly ash, an industrial waste product from the burning of coal that is commonly used to produce modern, green concrete. “There is not enough fly ash in this world to replace half of the Portland cement being used,” said Monteiro. “Many countries don’t have fly ash, so the idea is to find alternative, local materials that will work, including the kind of volcanic ash that Romans used. Using these alternatives could replace 40 percent of the world’s demand for Portland cement.”
To quote Matt Ridley:
The discovery of how genes actually influence human behaviour, and how human behaviour influences genes, is about to recast the debate entirely. No longer is it nature versus nurture, but nature via nurture. Genes are designed to take their cues from nurture
Goodbye, nature vs nurture
Replace human for bee or for organism and I think the quote still stands. It is not that the behaviour of an organism is for the most part determined by it genes, or either that is is determined by it nurture.
Nurture will give direction, Nature will limit the abilities.
How much you'll train a dog, it will never be able to play chess. How much you'll train a toddler, it will never be able to have capabilities to follow a scent trail like a bloodhound.
OT: safari does support some emacs key bindings:
see for example http://www.danrodney.com/mac/
It might be easier to reverse this law:
Any photo that has not been manipulated should indicate that 'the photo was not altered in order to modify the appearance of a person.'
Might be a whole lot cheaper.
And what about reproducibility?.
It would be rather hard too say "Oh yeah, I confirmed that experiment in my laboratory". If something would be wrong wired and thereby giving some false positives, how do you test for those? They must have some redundant checking mechanism somewhere...
This would imply that for a certain software product the US version would cost less than a localized version. A quick look tweakers price watch seems to confirm this.
If you look at this page you see that the US Int. version for Microsoft Office PowerPoint 2007 costs 113,18 euro whereas the dutch version costs 240,30 euro.
I know, statistically "one" means "none" and I'm not sure what the "US Int." means. Are there any other examples where the non localized version is cheaper than the localized version for the same software product?
Well... some biologist do have a problem with the Bdelloid rotifers.
John Maynard Smith, not a small thinker among biologist, called these creatures "An Evolutionary Scandal".
It is true that bacteria produce asexuall, but they still exchange genetic material using conjugation.
probably not... viruses are often host specific. They have to attach to specific receptors to enter the cell. So as long as the bacteria in our digestive tract do not share the surface proteins with Listeria, the bacteriophage will only tarcet Listeria.
Since the kernel is the interface to the hardware, it would be more precise to say that they both have the same motor and wheels etc, but are laid out with a different dashboard, steering wheels, gears (?), turbo and all other things that are between the driver and the hardware of the car (whatever that might be)
Can you take notes on it?
I often write notes in my books with a pencile, but it can be very cumbersome to erase those notes (especially on low quality paperbacks).
It would be nice if you could scribble something and the reader would save it to a separate file, so the reader would only have to overlay the notes over the pdf. One could even exchange notes etc. to produce annotated books.
Ada is named after Ada Byron (Lady Lovelace)...
But it definitely did not attract a lot of eager yound males
Maybe they should have named it Britney or something
I do not think that hardware will be the best the best discriminator for choosing the best distro.
I think (but I could be wrong) that your experience with linux would be a better indicator for the kind of distro you want.
If you have little experience with linux I would go for mandrake (or something other very userfriendly distro).
If you want to squeeze all the performance from your hardware go for linux-from-scratch (and as a bonus learn an awfull lot in the process).
I would say that most distro should perform about the same without tweaking.
Probably the most perceived performance difference will be in the window mananger you will install. (eg BlackBox(light) -> WindowMaker (some what heavier) -> KDE (heavy))
It is called the Mpemba Effect.
More on this phenomenon (history en possible explanations) here
(S + C + W + N) / B<br>
Ooohh that is way to simple...
*Real* formulas have at least one sinus function,
pi should be involved somewhere and to give it that real scientific look, sigma and unknown variables
So i gave you function a bit of pepper:
e-1 x
-- S + sin(C) + w N
\ ______________________
/
-- pi * B
Now.. it really works!
I think it is running minute slow:
The Two Clocks
Which is better, a clock that is right only once a year, or a clock that is right twice every day? 'The latter,' you reply, '"unquestionably.' Very good, now attend.
I have two clocks: one doesn't go at all, and the other loses a minute a day: which would you prefer? 'The losing one,' you answer, 'without a doubt.' Now observe: the one which loses a minute a day has to lose twelve hours, or seven hundred and twenty minutes before it is right again, consequently it is only right once in two years, whereas the other is evidently right as often as the time it points to comes round, which happens twice a day.
So you've contradicted yourself once. 'Ah, but,' you say, 'what's the use of its being right twice a day, if I can't tell when the time comes?' Why, suppose the clock points to eight o'clock, don't you see that the clock is right at eight o'clock? Consequently, when eight o'clock comes round your clock is right.
'Yes, I see that,' you reply.Very good, then you've contradicted yourself twice: now get out of the difficulty as best you can, and don't contradict yourself again if you can help it.
You might go on to ask, 'How am I to know when eight o'clock does come? My clock will not tell me.' Be patient: you know that when eight o'clock comes your clock is right, very good; then your rule is this: keep your eye fixed on your clock, and the very moment it is right it will be eight o'clock. 'But--,' you say. There, that'll do; the more you argue the farther you get from the point, so it will be as well to stop.
Lewis Carroll: ca. 1850 In: The Rectory Umbrella, M.S. First published 1898.
source
A few years ago there was a big political upheaval about eugenics in a scandinavian country.
I think it was Sweden... not sure..
It was about forced sterilization that ended somewhere in the 70's.
Europe was shocked (especially the netherlands where I'm from, because normally they see the Swedish country as a role model).
I'm not sure if it is all true (google finds a lot if your query it for "sweden eugenics").
But still it is quite frighting what a governement can do.
Maybe a Swede can comment? My memory is probably not really accurate
There is no importance in evolution. It is simple algortihm.
It just happens.
Futhermore species do not replicate.
Organisms do. To be even more precise genes do. Therefore the level of selection is the gene (or organism if you prefer... doesn't matter).
Here you touch a very senstive topic for biologist.
Like young boys, biologist get nervous if you start talking about sex.
Why? The reason is simple:
Biologist do not really understand sex.
Giving up half your genes! It must be compensated by something really big!
Some hypothesis do exist. But the do not really involve group selection. Some candidates are:
Until now the best candidate is The Red Queen.
If you are interested in the origin of sex...
Google is good info as well....
In biology death is not really seen as a "function" of life.
It is indeed an effect of limited environmental resources. But not in the way you just described it.
Evolution is not about species but about individuals (or better put about replication and survival of information by means of selection).
Suppose in a population two kind of types exists.
One type tries repairs itself whenever anything breaksdown. This will cost (a lot of) resources.
Another species has a different strategy. It puts some of its resources in offspring and some in maintenance.
Which type would increase in the population?
If we would bend this analogy to daily life it would be something like this:
You have a limited amount of income.
You need a car for transportation.
What would you do?
1)
Always repair your car (whatever dent or scratch) or
2) only invest in crucial maintenance and replace it after x years with a new car, when maintenance gets too expensive?
As you might have guessed, organisms go for option 2, it costs less.
The ones that would go for option 1 would have to compete all the time with type 2 and the offspring of the types of 2. Type 2 will win.
A side effect is that reproductive organs are not repaired all the time. Therefore selection stops for an individual after its reproductive age.
The rest is evolutionary free lunch (for better or worse).
If a gene would exist that would give an organism a reproductive advantage in the beginning of its life, but would give a stong detrimental effect after its reproductive age (death, for example), it would be still favoured by natural selection.
Therefore death is a simple outcome of a cost/benefit analysis. Immortality is simple too expensive.
Probably RNA came first..
It is less stable than DNA but is has shown to be able of enzymatic activity.
RNA is still used as a katalytic agent in cells (rRNA for example).
It therefore possess two very import biologic attributes: it can hold information and it can influence its environment by means of katalysis.
So it could be the ultimate first replicator.
It was a very popular hypothesis (don't know if it still is) that life started with RNA (google for "RNA world" or something)
Maybe is somekind of variation of Moore's law.
On April Fools' Day your GMail storage will double and the funniness of Slashdot jokes will be halved.
As far as I know it doesn't...
Here is some more info about paging and swapping under unix
AFAIK a page is an group of memory addresses that are being changed/addressed at the same time.
But I could be mistaken
I often see this quote "Information wants to be free". But I really do not understand why that should be so.
I would assume information "wants" to be duplicated in a darwian sense. But why should it want to be free?
DNA prefers to be nicely protected in the membrane of the nucleus, but I'm probably stretching my own analogy to much here.
It think it is moslty due to the nature of the language.
If a project gets complex, and you don't have a compiler to check your code before it runs, refactoring gets really difficult. You can still do some sort of unit testing. But the combination of unit testing and strong type language is much more powerfull.
If refactoring gets difficult and adjustments have to be implimented due to requirement changes, bugs will start to appear. And they will only rear their heads once the code is executed.
A class might still pass the unit test but without interface checking of a compiler you are never certain that other code using that class will not fail.
I could be doing something wrong but often when I have to change code in php I use grep to check whether other code is using that function etc.