Germany Looking for Nuclear Graveyard to last One Million Years.

[Angra Mainyu]

First energy need not be produced. Billions of people are 'living' without benefit of it.

But it is produced, and it will be produced, and a question is why would you oppose nuclear energy but not other forms of energy that cause far more suffering and deaths.

At any rate, nuclear energy will continue to be produced, more nuclear reactors will continue to be made, and so on. Anti-nuclear religionists might stop them by spreading their religion in democratic countries. But non-democratic countries are not limited in the same manner. The question is not whether nuclear reactors will be made. The question is who will make them. It would be sad if authoritarian regimes win on this - though I reckon they very probably will win.

Man simply can't avoid fearing it more than he can appreciate benefiting from it.

This is not true. Many of us support nuclear power. We are humans too.
Now, it may be that most people will always be irrationally opposed to nuclear power. But for that matter, it may well be that most people will always irrationally have religious beliefs. That is their fault, though, and it's not wrong to point this out, even if it's unsuccessful in persuading most. And who knows, some people at least might be persuaded, or they might be inoculated against some religions at least.

That said, why do you think most people will adopt this particular religion, namely the anti-nuclear one?
Sure, it might happen. But maybe 1000 years into the future, people will go by other religions instead. Why are you so sure they'll go for this one always?

 

[fromderinside]

Humans aren't rational nor are humans governed by objective observation. Most humans are followers. If you need more there is much more.

 Brainstem!  Fight-or-flight response

Look. I've been arguing long and hard that we are one species they we shouldn't try to divide things by color, ethnicity, belief, or territory. Yet that's what we do consistently. I'm not going to blow my brains out about that any more than you're going to quit arguing observational evidence about energy production. It's what we do. Think of us as situational Men of La Mancha. We may even be remembered but our wills won't be imposed.

As for the religion you speak of it comes out of fear.

 

[bilby]

Nuclear fission is by far the least worst option. No matter how many tales you can find of actual or potential accidents in the nuclear power industry, they are dwarfed by the number of fatalities and potential fatalities in other generation technologies. Even wind and solar lead to more deaths per unit of power generation than nuclear. In the real world. Where those untrustworthy humans fuck shit up and fight for profits with worker's and third party's lives.

You are simply applying a double standard - nuclear power must be perfect, and cannot be; But you don't demand perfection from the alternatives - and if you did, you would see that they are even worse.

First energy need not be produced. Billions of people are 'living' without benefit of it.

Billions of people are dying needlessly due to its lack.

I don't give a rat's shit if it is the only solution. Man simply can't avoid fearing it more than he can appreciate benefiting from it. It's not about objective criteria at all. It's about human nature, which as an evolved being, I can assure you, is suicidal. As for double standards ask yourself why you insist on an objective answer when you clearly know humans are not objectively oriented.

Ask yourself this simple question. Why did philosophy not build upon objective observation and material manipulation when it is obvious humans were using both to great benefit thousands of years prior to Philosophy's founding fathers laying out rational argument. It's obvious. Objective argument was not what powered humans intellectual pursuits. That was Business and Engineering stuff that spoke for itself, was routine, was unworthy of systematizing at the time.

Things are no different now even though we have the scientific method front and center to some. The method is known to a miniscule minority of humans and it is of almost no value when making portentous decisions about society. How do people feel is operative. What can be objectively demonstrated is not so much.

As example: How does one explain liberal medicine deniers, One doesn't. Their fear of unknowns and their ability to insert bogus 'reasons' exceed their ability to make objective judgements. It's been obvious to me that I am not being objective when I throw up argument off point, out of fear from experiences, make special pleadings. I do this from fear and I know that fear is operative when considering political decisions.

So you are saying that I am right, but that your pessimism should be allowed to dissuade me from trying to convince anyone else that I am right?

In that case, I can only reiterate - Fuck off. You are not helping.

 

[fromderinside]

Not at all. I'm saying my pessimism is symptomatic of human consciousness of such as nuclear power. That if one permits others to wail without taking political action one is doomed to fail. I'm a very political animal. I'm not going to rage against the know nothings who cry fearfully. Rather I'm gong to work for political solutions to energy management.

Right now the fearful are winning the struggle in once inclusionist Germany, EU, America and Australia. One needs to throw up firewalls to blunt these people who wring their hands. In the US we are pushing a very popular notion that healthcare systems here are killing americans because people are kept away from it because of financial greed from big pharma and big insurance. We hate big here as much or more than we hate being seen as other than number one. We know medicarefor all is theproperroute. However it is too easy to cast that as big brother against big capitalist which is a losing position.

What we are doing is getting behind permitting those who love their insurance to keep their insurance while getting them to support coverage for the old and poor. Articles are coming out almost weekly about the cleavage between red and blue state longevity. Forget the notion that it's the poor within the red states that are skewing the statistics we point to access to medical care as the reason. It's tough for the conservatives to fault that argumet with their traditional "We made that" rhetoric.

My suggestion for you on nuclear power is to get elites behind the safety of a power sufficient society versus a very dooms day argument of "dying from pollution because of big this and that. Denigrate the safety of carbon based power, perhaps invoke the threat of communism as the evil agent behind coal. We're trying to get the world to make more things without the need of wearing masks and carrying oxygen tanks rather than fearing the risk of nuclear accident. To get their one needs elites to set practices just as Pinker described happened in Britain when knife attacks got out of control in the late 1800s.

Reasonable people elites do not make. Ax grinders and high nose sniffers are the ones you need to recruit, to reverse their current leanings in fact. Don't believe me consult your gut.

 

[Loren Pechtel]

Isotopes of plutonium have a half-life up to 25,000 years, and some elements have half-life into millions of years, So, no, nuclear waste will not become ambient.
And from a practical point of view 10,000 is the same as 1 mil. You can't keep it stored in some facility, you have bury it deep under ground.
Reprocessing/recycling can only reduce amount of waste it does not eliminate it.

Nuclear waste IS a problem.

With proper reprocessing

Plutonium is fuel. It should be going back to the fuel plant, not to the waste pile. Thus the half-life is completely irrelevant.

And the 10,000 is quite relevant as you don't need nearly the engineering to keep it safe for 10,000 years that you need to keep it safe for a million.

Two simple solutions that meet the 10,000 requirement:

1) An old salt mine without nearby bodies of water. (I'm thinking of the disaster where someone drilling in a lake ended up draining the lake into a salt mine underneath.)

2) A muddy location on the abyssal plains away from seismic zones. Make sure your canisters are heavy enough that they'll sink into the mud. Once it's buried transport is very slow, when the container eventually fails the stuff disperses very slowly.

Note, also, that the leakage even from a failure long before the 10,000 years is going to release very little radioactivity.

And while you're at it, note that over the very long run nuclear power reduces radiation exposure. When we mine and burn up the uranium it won't be releasing radon.

 

[Loren Pechtel]

But the longer the half life the less dangerous it is.

Actually it's opposite in practice. Short lived isotopes are less dangerous because you can simply wait until they decay.
Long lived, even very long lived ones are active enough to kill you instantly if you have enough of it.
For example, 1 micro-gram of of some isotope with mass=100 and half-time 100 years will have :
6e23*log(2.)/(100.*365*24*3600)/100./1e6 = 1318773.17458133 decays per second
That's 1.3 million decays per second, typical background radiation count is 1 hertz.
so even with half life 100,000 years 1ugram would still be 1300 times above background.

Math fail!

It's not 1.3M / 1000, it's 1.3M/ 2^¹⁰⁰⁰ which is almost certainly exactly zero as you can't have a fraction of an atom.

Assuming your background number is right (I don't think it is) it will be down to that level in 2000 years.

 

[Loren Pechtel]

But the longer the half life the less dangerous it is.

Actually it's opposite in practice. Short lived isotopes are less dangerous because you can simply wait until they decay.
Long lived, even very long lived ones are active enough to kill you instantly if you have enough of it.
For example, 1 micro-gram of of some isotope with mass=100 and half-time 100 years will have 6e23/(100.*365*24*3600)/100./1e6 = 1902587.51902588 decays per second
That's 2 million decays per second, typical background radiation count is 1 hertz.
so even with half life 100,000 years 1ugram would still be 2000 times above background.

The Bq is so insignificant that it's widely called the 'Buggerall'

A typical adult human has a radioactivity of about 8,000 Bq (or Hz, if you prefer).

And if you're interested in the impact on human health, you need to talk Sv; The raw decay rate is pretty uninformative.

You need to be exposed to at least 100mSv/year to show any detectable health risk. This is not particularly easy to arrange, particularly not via spent nuclear fuel.

If LNT is right the risk is there even below 100mSv/yr, it's just too low to measure. Descending into the noise floor doesn't mean it's gone. By LNT 100Sv of low-level exposure = 1 death no matter how you divide it up. (Acute is another matter--you can kill 10 people with those 100Sv if you apply it all at once and whether LNT is right or not has nothing to do with that.)

Note, also, that if radiation homeostasis is right such radiation is considerably less harmful than the same dose from medical imaging and the like. Every data point we have that shows harm consistent with LNT involves exposure over a small fraction of the total time, but every data point we have for continuous or near-continuous exposure shows a risk below LNT.

 

[Loren Pechtel]

First energy need not be produced. Billions of people are 'living' without benefit of it.

Billions? I think the number is more like dozens. Even if you don't have electricity in your house that doesn't mean you aren't using products produced with electricity. Only those completely cut off from civilization get no benefit from electricity--and the world can't support anything remotely like the current population at that tech level.

 

[barbos]

But the longer the half life the less dangerous it is.

Actually it's opposite in practice. Short lived isotopes are less dangerous because you can simply wait until they decay.
Long lived, even very long lived ones are active enough to kill you instantly if you have enough of it.
For example, 1 micro-gram of of some isotope with mass=100 and half-time 100 years will have :
6e23*log(2.)/(100.*365*24*3600)/100./1e6 = 1318773.17458133 decays per second
That's 1.3 million decays per second, typical background radiation count is 1 hertz.
so even with half life 100,000 years 1ugram would still be 1300 times above background.

Math fail!

It's not 1.3M / 1000, it's 1.3M/ 2^¹⁰⁰⁰ which is almost certainly exactly zero as you can't have a fraction of an atom.
.

Brain fail, you don't understand what I actually calculated. And what you calculated makes no sense whatsoever

 

[barbos]

Isotopes of plutonium have a half-life up to 25,000 years, and some elements have half-life into millions of years, So, no, nuclear waste will not become ambient.
And from a practical point of view 10,000 is the same as 1 mil. You can't keep it stored in some facility, you have bury it deep under ground.
Reprocessing/recycling can only reduce amount of waste it does not eliminate it.

Nuclear waste IS a problem.

With proper reprocessing

Plutonium is fuel. It should be going back to the fuel plant, not to the waste pile. Thus the half-life is completely irrelevant.

And the 10,000 is quite relevant as you don't need nearly the engineering to keep it safe for 10,000 years that you need to keep it safe for a million.

Two simple solutions that meet the 10,000 requirement:

1) An old salt mine without nearby bodies of water. (I'm thinking of the disaster where someone drilling in a lake ended up draining the lake into a salt mine underneath.)

2) A muddy location on the abyssal plains away from seismic zones. Make sure your canisters are heavy enough that they'll sink into the mud. Once it's buried transport is very slow, when the container eventually fails the stuff disperses very slowly.

Note, also, that the leakage even from a failure long before the 10,000 years is going to release very little radioactivity.

And while you're at it, note that over the very long run nuclear power reduces radiation exposure. When we mine and burn up the uranium it won't be releasing radon.

Plutonium is not currently fuel. Current reactors produce unmanageable amount of waste which is currently accumulated in storage.
Plutonium is not the only waste with long half life, anything with above few years is too much for simply storing in these casks because you have to attend to these casks for hundreds of years and this is what they currently doing - storing and hoping that better way will be invented in the future.

 

[Angra Mainyu]

Humans aren't rational nor are humans governed by objective observation. Most humans are followers. If you need more there is much more.

 Brainstem!  Fight-or-flight response

But it's not that I need more. It's that you oppose nuclear power. You were not just saying that most people are followers and/or that they oppose nuclear power. Why do you oppose it?

As for the religion you speak of it comes out of fear.

They need to be epistemically irrational in their assessment in the first place in order to be afraid. Given the information available to them, they should not be afraid. And by the way, historically, it seems very probable majorities of people in some Western countries at least were not anti-nuclear, or afraid of nuclear power.

 

[Angra Mainyu]

So you are saying that I am right, but that your pessimism should be allowed to dissuade me from trying to convince anyone else that I am right?

In that case, I can only reiterate - Fuck off. You are not helping.

His pessimism should not dissuade you, of course, but evidence for the lack of effectiveness of trying to persuade the opponents of nuclear power might be a more significant hurdle, at least if that is one's aim. Then again, maybe you are not trying to persuade them but rather, fence-sitting potential readers, so there is that, and maybe that will work (also, sometimes it's fun to just debunk religions, and it's well-deserved ).

At any rate, thanks for the good and informative posts. I don't need convincing (not a religionist) , but they're interesting.

 

[fromderinside]

Humans aren't rational nor are humans governed by objective observation. Most humans are followers. If you need more there is much more.

 Brainstem!  Fight-or-flight response

But it's not that I need more. It's that you oppose nuclear power. You were not just saying that most people are followers and/or that they oppose nuclear power. Why do you oppose it?

As for the religion you speak of it comes out of fear.

They need to be epistemically irrational in their assessment in the first place in order to be afraid. Given the information available to them, they should not be afraid. And by the way, historically, it seems very probable majorities of people in some Western countries at least were not anti-nuclear, or afraid of nuclear power.

Think of me as a fear parrot. Yes I do have fear of nuclear power. I realize I nearly lost my father as he did his job. So there's that. I also had radium treatment for a pigment abnormality when I was a baby that was successful. Later My thyroid died. Now I'm medicated, fighting depression, with vascular disease, with all sorts of bad behavior and imagined causes to blame. I see the merit of your arguments because I've made many of them over the years.

My attempts have been for you, the advocate, to show you know how to go about overcoming the fearful.. Plenty of clues.

Instead of that you try to execute the messenger.

You need to convincingly provide an argument method for overcoming innate fear of the unknown in those fearful people. You have to sway them to get what you want done. Then I'll pat myself on the but for being one of those who pushed enough for you to actually get something done to your satisfaction.

It's not me you need to convince and it's not me that is determined to convince others of the validity of going nuclear. I've already laid out my approach. And I've supported it with examples of others who have succeeded in overcoming fear of what those who don't know for progress.

A finger pointed in blame is about as useless as pointing a stick at an armored enemy and saying "bang".

 

[bilby]

The Bq is so insignificant that it's widely called the 'Buggerall'

A typical adult human has a radioactivity of about 8,000 Bq (or Hz, if you prefer).

And if you're interested in the impact on human health, you need to talk Sv; The raw decay rate is pretty uninformative.

You need to be exposed to at least 100mSv/year to show any detectable health risk. This is not particularly easy to arrange, particularly not via spent nuclear fuel.

If LNT is right the risk is there even below 100mSv/yr, it's just too low to measure. Descending into the noise floor doesn't mean it's gone. By LNT 100Sv of low-level exposure = 1 death no matter how you divide it up. (Acute is another matter--you can kill 10 people with those 100Sv if you apply it all at once and whether LNT is right or not has nothing to do with that.)

Note, also, that if radiation homeostasis is right such radiation is considerably less harmful than the same dose from medical imaging and the like. Every data point we have that shows harm consistent with LNT involves exposure over a small fraction of the total time, but every data point we have for continuous or near-continuous exposure shows a risk below LNT.

LNT isn't right.

LNT is bloody stupid.

All life on Earth evolved to tolerate at least some background radiation - which implies molecular repair mechanisms.

Indeed, from a molecular biology perspective, radiation damage is pretty much identical to free radical damage - if we can survive all this oxygen, we can certainly survive a fair bit of radiation.

LNT is the concept that as it is deadly to jump off a twenty story building, it's therefore also deadly to walk down the stairs - which is a series of small falls that total the same overall descent. If that strikes you as an absurd concept, then you should immediately be hugely suspicious of LNT when applied to radiation exposure.

 

[fromderinside]

First energy need not be produced. Billions of people are 'living' without benefit of it.

Billions? I think the number is more like dozens. Even if you don't have electricity in your house that doesn't mean you aren't using products produced with electricity. Only those completely cut off from civilization get no benefit from electricity--and the world can't support anything remotely like the current population at that tech level.

Have you ever wondered why Social organizations like Rotary choose to provide mechanically driven water systems, rudimentary wood and peat burning stoves, and basic tools for planting and growing crops in places like Angola, Myanmar, Bangladesh, Honduras, Bolivia, ..... In fact some clubs actually go and dig wells in rural Argentina, provide pedal driven phones in near city locations in many of the less industrialized countries.

The right answer is billions of people have no power lines within two hundred miles of where they live. Having access to grain delivered to refugee camps from rich countries is not benefit from it is sad.

What's worse is that perhaps 10 percent of the world population is still illiterate. UNESCO Literacy http://uis.unesco.org/en/topic/literacy

Globally, however, at least 750 million youth and adults still cannot read and write and 250 million children are failing to acquire basic literacy skills. This results in an exclusion of low-literate and low-skilled youth and adults from full participation in their communities and societies.

OK. that's a derail. sorry.

 

[Angra Mainyu]

My attempts have been for you, the advocate, to show you know how to go about overcoming the fearful.. Plenty of clues.

Actually, that is not what you were appear to be doing at all when I replied to you. bilby was advocating nuclear power - with much better arguments that I could give, given his expertise on the matter - and you made the following claim:

How is identifying liberalism with science letting liberal science deniers off the hooK of being science deniers? On nuclear power in the hands of man, particularly man with a profit motive, I'm absolutely denying science has anything to do with whether nuclear power should be used for energy production. It is the greed and power based attitudes of those who gravitate to profit and control that tip my dials toward "DON'T DO IT" even in Germany.

That's where I replied to your post first. Now, if you have now dropped your advocacy against nuclear power, that's good.

Instead of that you try to execute the messenger.

I'm not trying to shoot the messenger. I was challenging your argument against nuclear power, and I'm continuing the conversation.

You need to convincingly provide an argument method for overcoming innate fear of the unknown in those fearful people. You have to sway them to get what you want done. Then I'll pat myself on the but for being one of those who pushed enough for you to actually get something done to your satisfaction.

I'm not trying to convince them. I'm challenging your arguments against nuclear power. If you drop your arguments against nuclear power, that's great. If you do not, I keep challenging them, with reason.

It's not me you need to convince and it's not me that is determined to convince others of the validity of going nuclear.

Well, I don't need to convince you though convincing you would be nice, but at least I attempt to convince readers not to buy into your anti-nuclear arguments (see quote above). If you just drop them, good.

A finger pointed in blame is about as useless as pointing a stick at an armored enemy and saying "bang".

Actually, I think an argument against your argument might reduces the chances that readers would buy into your anti-nuclear argument.

 

[fromderinside]

Actually, I think an argument against your argument might reduces the chances that readers would buy into your anti-nuclear argument.

OK so I use a hammer Angra Mainyu. My anti-nuclear argument is objectively crap. Anyone not seeing that is probably unreachable. My 'personal' touches are even worse. They're like reading the pleadings of an anti-vaccination liberal denier.

Early on I observed Germany has moved from a tribal culture to a universal culture back to a tribal culture. That observation was intended to 'splain the current German fear of nuclear power. It was meant as a signal that political arguments need be made.


My anti-nuclear arguments that followed feel comfortable and meaningful to a fearful one which is why I put them up there for bilby to shoot down politically.

What do I mean by that? How about:

"FDI, doesn't cancer scare you? You know people who have had cancer who have died from cancer. It's in the news everyday. It's something you know about. You have relatives who've had and died from it. Well doctors use radiation isotopes to target and destroy cancer as one of their main weapons to help you fight and beat cancer."

"Besides, FDI you've gotten through life without a brown Gorbachev patch on your face because doctors used radiation to remove it when you were a baby. And here you are admitting you are afraid. Yet you have lived a very successful life without social facial stigma. I'm sure you thank the doctor who gave you your name because of that success every day. Yes FDI you fear radiation but it has made your life wonderful."

"Now, FDI, if nuclear power can do the same by eliminating dangerous carbon compounds from polluting our skies and lands while increasing the supply of useful electricity wouldn't the clean air that results be worth a bit of uncertainty about something that provides so much quality of life benefit."

-Sign Here-

That, Angra Mainyu, is sample of the type of tack I want bilby to try. With his knowledge and persuasive skills I'll bet he can create a humdinger.

Notice I never assaulted the target even once. Political.

 

[Angra Mainyu]

Early on I observed Germany has moved from a tribal culture to a universal culture back to a tribal culture. That observation was intended to 'splain the current German fear of nuclear power. It was meant as a signal that political arguments need be made.

I don't know where you "observed" (or rather, claimed) that. Yo did say that " Tribalists are in ascendency" but did not make anything like that specific claim about Germany.
But regardless, if you are not actually arguing against nuclear power, that's good. You could have started with that, and we both would have saved some time.

 

[bilby]

Actually, I think an argument against your argument might reduces the chances that readers would buy into your anti-nuclear argument.

OK so I use a hammer Angra Mainyu. My anti-nuclear argument is objectively crap. Anyone not seeing that is probably unreachable. My 'personal' touches are even worse. They're like reading the pleadings of an anti-vaccination liberal denier.

Early on I observed Germany has moved from a tribal culture to a universal culture back to a tribal culture. That observation was intended to 'splain the current German fear of nuclear power. It was meant as a signal that political arguments need be made.


My anti-nuclear arguments that followed feel comfortable and meaningful to a fearful one which is why I put them up there for bilby to shoot down politically.

What do I mean by that? How about:

"FDI, doesn't cancer scare you? You know people who have had cancer who have died from cancer. It's in the news everyday. It's something you know about. You have relatives who've had and died from it. Well doctors use radiation isotopes to target and destroy cancer as one of their main weapons to help you fight and beat cancer."

"Besides, FDI you've gotten through life without a brown Gorbachev patch on your face because doctors used radiation to remove it when you were a baby. And here you are admitting you are afraid. Yet you have lived a very successful life without social facial stigma. I'm sure you thank the doctor who gave you your name because of that success every day. Yes FDI you fear radiation but it has made your life wonderful."

"Now, FDI, if nuclear power can do the same by eliminating dangerous carbon compounds from polluting our skies and lands while increasing the supply of useful electricity wouldn't the clean air that results be worth a bit of uncertainty about something that provides so much quality of life benefit."

-Sign Here-

That, Angra Mainyu, is sample of the type of tack I want bilby to try. With his knowledge and persuasive skills I'll bet he can create a humdinger.

Notice I never assaulted the target even once. Political.

I am not interested in playing stupid games with you. You are not my sensei, guru, or guide; I am not your student. You are being unacceptably presumptuous, if you are seeking to lead me to a style of argument that you would prefer, and even more so if you imagine that you have a unique insight into what arguments might be effective with my target audience - which you are completely unqualified to identify.

You are not helping.

 

[Bomb#20]

I take it by "evolutionary biology" you mean "people evolved from animals".

I take it from that question that you are entirely ignorant of both the process of evolution and the theory that describes that process. People ARE animals.

Richard Feynman related a story from his childhood. His dad took him on a nature walk in the woods and they saw some birds, and Richard told his dad about a boy in his class who knew all about birds and when he saw one could always say what kind of bird it was. His father told him that when you know the name of a kind of bird, that means you know something about people -- it means you know that people call that bird, say, a "wren". It doesn't mean the boy knew anything about wrens. To learn something about a bird, Feynman's dad said, "Let us look at the bird."

The point is, when you lecture me that "People ARE animals.", you are not saying anything about animals -- in fact you are not saying anything about science at all. You are saying something about scientists -- that scientists call people "animals". That is their choice of terminology. It's a cultural convention among scientists. There's nothing wrong with their convention -- it has a lot to recommend it -- but this mustn't mislead us into supposing it's anything more than a cultural convention. If one person says "people evolved from animals" and another says "people are animals", this implies no more about which of the two better knows the theory and process of evolution than if one person says something about evolution in English and the other in French. There was once a time in Europe when naturalists couldn't get taken seriously if their monographs weren't in French. But that was snobbishness, not science.

Science is about facts, not about labels; and if an education in science teaches a person anything it should be how to tell the difference.

Get over it.

It's quite common for people to use the word "animal" to refer to a paraphyletic category that excludes humans. It's a terminological convention. One can correctly express the same scientific concept using many different terminological conventions. Get over it.

As for the "science denial" of right wingers - maybe it is a necessity, not only to preserve certain superstitions with which they were raised, but also to enable them to accept the unbelievable from their leaders.

What's your point? A plague on both your houses.

Scientists Are Trying to Figure Out Why People Are OK with Trump’s Endless Supply of Lies

Did they get a grant for that? I once read about scientists getting a grant to figure out why people burn their mouths on pizza.