Saturday, June 29, 2013

some praxis of assumption

If the title sounds strange to you, you probably want to skip this one. Please tolerate.

Why do I even post it at all? Someone sent an email to me this week asking why I always hold back SO MUCH.  Being under pressure, I replied briefly:
First, you are right that I usually do not tell the whole story on anything.
That pains me, and it is contrary to my instincts... and yet, like a
dog who frequently gets his nose hit by a newspaper, I still regularly
get hit in the nose by folks who object to
how much I do try to reveal, small as it is as a fraction of what is there.
Of course, from the NSF side, there are also restrictions on what I say
under the Privacy Act, which is pretty sancrosanct around here.

We live in a world where people have so many, many hot buttons.
Where more than half the challenge in developing any new idea is the
planning for the "antibodies" that come into effect as soon as one
gets so far as 1% in to the story (as in the movie Inception).

But, as the guy said, I am getting to an age and a situation where there is not as much to lose
in an obscure post, where I am not shoving things down anyone's throat.


But first, an annoying background. (It reminds me of a girl I knew long ago,
when I was a boy -- a girl  whom I might possibly have married -- who complained about
how her grandfather would have endless background stories within stories. But that grandfather
was one of the most important wealthy forces behind the scenes in those days, and not
all a stupid or frivolous person, quite the opposite... So I apologize for doing the same, but...)

A month or two ago, in the bar of a waterfront hotel in Singapore, I met up with good old Eshua of the House of David and Emmanuel ( a scholar loyal to the eastern Orthodox Church). A lot of the discussion involved some ancient texts in Aramaic and in Greek (predating the gross revisionism
of folks like Constantine) which they enjoyed talking about, as some folks enjoy talking about movies they saw when they were young. At one point, I said to Emmanuel something like,
"Oh, for myself, I'm really not into his believing stuff. I see what I see, and I learn what I learn
from what I see and from logic, but I don't believe stuff I can't justify from experience."
He wondered whether he should be shocked and offended (while Eshua just smiled)... until I said just a little bit about what I have seen and experienced.  But I have already posted a bit about those earlier things... so no need to reiterate the basics. Not here. If you think that such things are crazy, you'd be better off looking at earlier posts, not this one.

And by the way, if you are excited by what you think you could do to get your way by use of such things, you would also be better off going to earlier posts. This is what some folks call a "Heisenberg thing;" it can come back to bite the observer, if you play with it in the wrong way without a deep integration of what you really do want to do and so on.  I remember an old Taoist teacher
(with a great citation index and patent revenue) who told me long ago, in the Cosmos Club in DC:
"Of course, we know how to induce enlightenment in a very short time, maybe a day. But the lengthy training and discipline is necessary to reduce the chances that  the person just dies the next day."


Ok, so what is "praxis of assumption" already? Praxis is basically just a fancy work for practice,
for practical experience and how to do stuff. There is a whole lot of praxis here, and I don't intend to
discuss it all here and now. Just a few basic ideas and points.

But what is "assumption"? Well, it's a technical term, from the Western esoteric tradition. Again,
I give some citations to that in earlier posts, and even in (which I haven't updated in years; apologies; partly a function of glitches in cyberspace, and glitches in schedule).

There are many "paths up the mountain," but for some folks there is a progression from playing with
local physical energy ("a kind of qi"), to the Great Quest for Out of Body Experience (OOBE),
to assumption, to something vaguely called cosmic consciousness or transcending time or enlightenment or nirvana or whatnot.  And many associated things.

When I started playing with the OOBE stuff, a long long time ago, I did speak to some folks who had been teaching or playing with such stuff, from a variety of cultures, mainly folks who also had PhDs or MDs and a respected base, who also had learned how much one has to hold back in today's world.
(Bit of a problem, that.) One of the key guidelines -- don't let yourself get fixated on what you expect. If you do, you will never get there. Your preconceptions of what it is supposed to be like are a major block to it happening. And also -- for different people, different angles work for creating the kind of relaxation and correlation that it takes. If your preconceptions are TOO strong, you will even fall into hallucinations, and that can get really bad; constant testing is essential.

Maybe the first key point is that OOBE is not inherently a BINARY phenomenon. People get excited by the fantasy of flipping a switch, and instantly turning in to some kind of superman.  It can be gradual or quick (faster with experience and desire), but it's always a continuum. And it always builds on what one actually feels, requiring a probing of what one actually feels instead of what one imagines or what one hopes to feel. (Funny how this contrasts with psychokinetic visualization,
but that's not for today.) There is a DEGREE of projection of consciousness and attention, and paths for extending that. Also, the issue of maintaining a high level of consciousness and memory when projecting is important; I think back to stories by Ingo Swann, who never could quite get his numbers straight.


Oops, but what is "assumption" already? Next up after OOBE, and far more interesting and entertaining, really.

You could think of it as "uberempathy," something Eshua could really appreciate. Not just mirror neurons, the brain's way of generating empathy, but something much stronger. So much stronger
that in some way it's like "becoming" another person, assuming so much of their self....

For me... I think back to the 1970's, when I taught classes at the University of Maryland,
and, among other things, was following the exercises ("experiments") which came down via H. Spencer Lewis.  So one day, with great discipline and motivation, I tried the basic "here you are,
you are now prepared and ready, here's how you can do OOBE." (I had actually had a bit of that long before, by other means, but wanted a bit more control and discipline and integration.) So I did, upstairs in my study. I decided I would project to my own living room, downstairs, a reasonably safe place to begin.

But when I got to the key stage.. it seemed very odd indeed. There were other people in the room.
I didn't feel like a disembodied spirit at all... and in fact... I quickly withdrew in shock.

And then I remembered something from the day before. The day before, I had asked my graduate
seminar course on global survival problems (like sustianability) to meet in my living room.
At one point in the discussion, one intelligent and intense older student, sitting on my big
orange couch up against the inner wall of the room, suddenly and uncharacteristically looked
totally freaked out. We tried to get some explanation, but he was very reluctant to say anything,
and the moment passed. What I saw was exactly what he would have seen...

In sum, I believe it was assumption, not OOBE. People are more attractive to me than empty floors and sidewalks. And for a lot of normal stuff, a time shift of plus or minus two weeks was pretty much the routine thing to expect. But of course, it took many, many assumption events with evidence
to build up a picture....

In fact, until about a year ago,  for maybe about twenty years (maybe thirty), I would take care to get more than six hours of sleep (the amount needed to discharge my normal brain requirements),
to stay 8 or 9 hours -- and then, punctuated by period of ordinary consciousness, I would have astral projection and assumption "dreams" which at times were quite useful, and verifiable.
Though of course it is not always pleasant to see directly how other people see yourself...

(Lately, I am more into that cosmic consciousness kind of thing, another story.)


So... some bits of the praxis...

Assumption, like OOBE, is not such a binary thing as one might imagine. For folks who
build intelligent systems... well, no, this is much more a neural network world than a binary computer world.

Normally, there is a discrete aspect, in that there is one other person. But the DEGREE of assumption
is also variable.

At times, it can be very similar to OOBE, really, loosely orbiting around another person.

Most often, it would occur when someone WANTED someone else to come by and help somehow.

Literary associations -- Philip Dick, Three Stigmata of Palmer Eldritch; Bruner, PLayers at the Game of People.  Nowhere near precise, but it sure sounds like someone else had some gross experience with this.

Another memory: a discussion time at the Rosicrucian Lodge of DC.  One woman recounts how
she was driving, her car got out of control, she knew it was beyond her skill to save the situation,
and she called to the cosmic to come and help, help especially to drive right. They guy she was talking to smiled, said he was in meditation at that moment, heard the call, came, and yes, there
was another mind moving her hands, controlling the wheel.  They correlated memories, etc.,
etc. I still remember that guy, a paragon of his community.

BUT... it is not binary. For example, I suspect he felt and moved her arms, but did not
transfer any sensations whatsoever form other parts of her body. The degree varies.
And of course, people's calls for help also vary.


So I must close this, without saying more, e.g. about the underlying machinery of all this.

Just... last night I had a qualitatively new experience with assumption deeper than before,
really oscillating between an assumption "dream" (what is the operational definition of "dream"?)
and cosmic consciousness kinds of stuff.. about ITAR regulation of space technology.
I tracked with someone else's thinking SO closely it took energy for me to see that
it was not truly my own thinking or memory... but he and I (working together)
remembered something he had written in a prior year on this subject, in technical detail,
with the kind of memory exploration and detail and analysis... probing HIS memory...
never quite did that before.  And in that area, we all do need help.

So maybe developing space technology can be a very enlightening exercise..
as some folks in India have been telling me...

But: last night's experience is an example where I need to think like a "proper Bayesian" --
attributing probabilities to more than one possibility, and adapting as new information comes in.
In my first person thinking.

I hurried to finish up because Luda offered me a chance to join her in a Saturday morning trip to Costco... We get to talk on the way, and when we got there I went to get a hot dog while she started on her list.  (Hey, $1.50 for  a big hot dog, plus a soda with refills.) When I got to our usual rendezvoous point, and I was waiting... without distractions... I decided I should relax and try to probe the memory from last night of working on ITAR... I had sensed that a certain key paragraph
was especially important, and I wanted to get whatever benefit I could from that memory. So
I started probing it, rght then and there in Costco...
And... my perspective changed. As I looked more closely, it was a draft on paragraph XV(a11)
of the Munitions List of ITAR. And... it seemed as if the feeling was right last night, when I
was vacillating, that it WAS my memory, not some nusual third party so much like me..
Last night, I looked at the evidence... because the memory was of having worked this
a couple of years before, I deduced that it couldn't be me... but I forgot the occasional time
slip, which can be greater when one is operating on another level. So this was a typical future thing.
Not assumption at all.

Oh, well. Of course, I don't remember whether we sorted out ITAR enough to save us all.
Maybe, maybe not. At that level, it would make sense to expect multiple parallel outcomes anyway..
but who knows?

Enough for one day.. other things to attend to...

Best of luck,


Tuesday, June 25, 2013

time and buidling the superbrain

It was neat a few months ago to read that google has put in a little money into a project
intended to build a true "quantum learning machine." There was a time a few years ago,
when none of the work on quantum computing envisioned building a true general purpose learning machine to exploit quantum principles. I started the field out with a few key investments (e.g. to Elizabeth Behrman, who worked to build a new community). I wonder whether my chapters in the
new books on memristors helped? (Note the endorsements on LinkedIn from Intel and HP.)

But... that's just background, to let you know this is not just vaporware.

Recently, on this blog, I gave you a link to a paper I gave at Yale, on what we need to do in order to build artificial brains as powerful as that of a mouse. "Start from vector intelligence, and then add three new ingredients.' That paper would be enough to keep us all busy for 100 years.

But... even though I fund other folks mainly for vector intelligence and the first of the three extra ingredients...

For myself, I like to look ahead sometimes.

So can we move ahead, and add three more ingredients, to get to a level of artificial intelligence so far beyond the human brain that I hesitate to name it. "The artificial God?" Oops -- that reminds me of the science fiction by C.S. Lewis... oops indeed. Better be careful with that one.

What are the three ingredients? As I see them, they are, in order of levels we see:
(1) Mirror neurons AND their perfection, from mouse to chimp to human to what we humans like to imagine we are (sane by nature if that's posisble);
(2) full exploitation of quantum effects;
(3)  full exploitation of "multimodularity" AS I would define that term, involving symmetry effects
more completely exploited than in the limited circuitry of the human brain, and some kind of collective intelligence.

OK, so if we just add (2) we actually aim at something more like a mute demigod.
'Way beyond what google has been funding; interesting enough, even if it's just one ingredient.
Should we call it the Odysseus project?  (The closest I can think of to a demigod known for intelligence.) Or the Janus project? (Looking forward and backward in time is the physical key to making it work.)

So how do we do that?

Unlike the quest for the mouse, this one requires some basic new directions in how we design and build circuits (electrical circuits, or optical circuits, or electro-optic -- or anything they use in quantum computing). I have been looking into that this past week.

A key starting point is my paper on "Bell's Theorem.." in the International Journal for Theoretical Physics, 2008 or 2009.  Such a straightforward paper, but different from conventional ways of thinking, and thereby requiring that people look closely at what they are reading.

One new direction I propose in that paper is a way to explain "Holt" style Bell's Theorem experiments, which disagreed BOTH with "local, causal hidden variable theory" AND WITH all the versions of quantum field theory in common use today. That one task could be a well-spent career in itself. One could argue that I was an idiot to do anything else myself after I saw this path... but
I do have a day job, and responsibility for so many other things.

The central idea there is that every object in an experiment has its own
(call it ETSP).  That's what you need to explain the Holt style experiment, and the many possible variations. (I coukld even imagine going to Waterloo, where Holt now works,
and going into the machine shop to make variations, and track how the model can fit not
only the original but the variations.) In my paper, I showed a simple ETSP model for
the usual, imperfect polarizer, which can handle Bell's Theorem experiments
WITHOUT involving Fock space. The whole experiment is basically just a simple graph of
objects, each with its own ETSP (nontrivial only for the polarizer), which can predict entanglement effects WITHOUT involving Fock space -- simply by doing a time-symmetric
Markov Random Field (MRF) analysis of this graph.

In essence ... we can do the same for much more complicated circuits, "simply"
by developing the ETSP for the lumped circuit components, using some combination of empirical and first principles (ab initio) methods for each component.


FOR EVERY circuity component we have on earth, I claim that a time-symmetric endogenous probability distribution is what really characterizes it. Why? Because every object we have on earth is essentially passive. ALL time-forwards phenomena are caused by BOUNDARY conditions,
which come from beyond the earth. (See the IJTP paper for more discussion of this.)
MRF analysis is what we really need here, for the general case, and for this kind of computer.

Those who are at the forefront of quantum computing should learn about the paper by Blais et al (over 900 hits on google scholar) showing how circuit QED allows a new mechanism to avoid decoherence and disentanglement, well beyond what schoolbuy QED would allow.
(cQED also fits empitrtical reality in areas where schoolboy stuff doesn't.)
But those fetaures of cQEDCare basically a subset of this more general PQED...
what we get in effect using the MRF approach.  And it fits more nagturally with
hardware and architecture for learning systems.

But do we really want to build Odysseus?

the math itself is already interesting enough... and maybe there are other machine shops
in the area...

Saturday, June 15, 2013

no fly zone in Syria?

After Obama's announcement about sarin gas, there is a lot
of speculation -- will there be a no fly zone, or not?

This is a classic case of binary thinking.  Are there really only two options?

From a purely technical point of view, I am a bit intrigued by a third posisbility,
which might or might not make sense: instead of declaring a no fly zone,
why not declare (or just perform) experimental reseatrch? Use it as a testbed for
new technology? Or as an evaluation of "Iranian technology"?

Why not see what kinds of drones trigger the antimissile systems, and
experiment with ways to try to remove them? If they work, then there is a chance to
do a no fly zone, but the experiment would be an interesting exercise in any case.

 But a totally different thought -- if the Russians are sincere in their worries
about Al Qaida, they should "conspire with the US" to tro to divert the next big
push AWAY from Aleppo (a key base for more progressive society and future
economic development, not a Sunni heartland) towards the environs... looking maybe like a siege... but crushing more the core base of Al Qaida in more remote locations.
And who needs Hezbollah?

Whatever... just fuzzy thoughts of a morning... I need to put more energy into things OTHER
than Syria, but can't help noticing a few things floating around...

Best of luck,


Sunday, June 9, 2013

STRESS -- new science of what it does to you and to schools

There is new science here, far beyond what you can find in popular articles on stress. But I'll try to work my way to the science through examples and stories.

Imagine a two-year-old playing with a ball in the living room. The ball rolls behind a couch.
When the kid was young, she might have suddenly thought the ball does not exist. Out of sight, out of mind. After a moment of perplexity, she would have moved on to other things in the room. But by two years of age (or earlier), the kid has learned "object permanence." She can "see" in her mind that the ball is still there, behind the couch, and she will probably crawl around to get it, and keep playing.

BUT -- as she plans to crawl around -- what if she suddenly hears her mother screaming behind her,
and hears other worrisome loud noises. She could turn around to look... and then... when the alarm is
over.. the ball may no longer exist in her mind. She forgot all about it. She is especially likely to forget if the alarm was really scary to her.

So what is really going on here?

"Object permanence" is a kind of memory, but it's not like the long-term memories which we have to work to recall. It's more like "short-term memory," part of our image of the present state of our immediate environment. The long-term memories are stored in a kind of hard-wired form in the brain, embedded in stable chemicals. But the short-term memory is stored in electrical form, as a kind of reverberation of electrical currents in the brain.

This past Wednesday, I heard a talk by Professor A. Arnsted, a neuroscientist at Yale, on her current research into short-term memory and the things which disrupt it, which have far-reaching implications for human life and human development.

It seemed as if Prof. Arnsted had been hired to try to fill the shoes of Professor Patricia
Goldmann-Rakic of Yale one of the truly great systems neuroscientists, whose work was
really essential to those of us trying to understand how brains really work (and how to build them).
Goldmann Rakic was famous for work on the frontal lobes of the human brain, the part which
are often considered the highest part of the human brain. "Great frontal lobes," said Isaac Newton --
and many after him.  She studied how "working memory" (short-term memory) results from
reverberations in the neutral networks of the frontal lobes.  Many of us in the neural network engineering area have followed up on this idea; "time-lagged recurrent networks" (TLRN) bring the same kind of power to artificial neural networks. This time-lagged "memory" is crucial to
good performance in things like controlling car engines in a way which reduces pollution and increases mileage; it is widely used in key industries, even though many ivory towers have yet to
catch on to what is really going on.

Years ago, I disagreed with the idea that our working memory, our short-term memory or "reconstructed image of reality," lives in the revervebrations in the frontal lobes. I argued that
it exists in ALL the time-lagged reverberatory connections in ALL of the cerebral cortex.
(See some of the books edited by Karl Pribram.) Many agreed. Students of Goldmann-Rakic have come to NSF, explaining that it is the reverberation, not the frontal lobes, which contain the memory.

(What disrupts our memory, and our "seeing" of things we do not see?
How does that affect our schools? I'll get to that...)

But then a story.

In 2005, the International Neural Network Society decided to hold its annual meeting
in Montreal. It invited a top neuroscientist from Montreal to give a big plenary talk on HIS research
on the frontal lobes. After fiddling with his laptop for half an hour, he described a whole series of experiments he did. In essence, he said: "My experiments do not agree with Golmann-Rakic's explanation. Let me give you all the details..." Many people did not understand the details. It took some energy to make real sense of what they mean. So I voiced and published my own interpretation of what he was saying (in the journal Neural  Networks): "The most advanced leading edge parts of the human brain are two specific parts of the frontal lobes -- orbitofrontal and dorsolateral. These
advanced parts of our brain begin to help us cope with the two most fundamental challenges facing our human mental abilities. These challeneges are to answer the two great questions in human life:
(1) where did I leave my car this time in the parking lot; and (2) what was it that I was trying to do anyway?" Of course, (1) is just an example of a more basic principle.

At Yale last Wednesday, I was delighted to hear that Arnsted has done experiments exactly on humans' ability to remember where they left the car in the parking lot. I asked Luda this morning:
"Did she get permission to meet hapless shoppers in Costco, terrify them, and watch how they forget where they left their cars?" Of course not -- but she did get permission to do something in the lab of the same flavor. (And also, experiments on people forgetting what it was they were trying to do.)

As she spoke, she reminded me of a woman I once knew named Kathie,
who spent much of her life trying to understand how strong hormones affect human thought and human behavior.  (I never talked about she affected my own hormones, except to Luda, but that was
certainly part of my own working memory, which did get recorded in my permanent chemical and even spiritual memory.) She talked about more than a dozen key hormones which change how things
work in the frontal lobes. She said that she has focused on three MOST important hormones, which have the biggest effect: (1) adrenalin (more precisely, norepinephrine), which is basically a fear response; (2) dopamine, which is a kind of reward or hope response; (2) acetylcholine (ACTH?),
which increases general awareness.

Basically, in situations of stress or fear, she has traced how adrenalin blocks or shuts down
those reverberations.  So the scared little girl forgets about that  ball behind the couch.
She has published lots of papers describing the details -- but in this talk to the engineering community, she basically told us to look up her papers for details. (I will, but not today.. too many emergencies..).

Since stress shifts the brain to reliance on lower, less capable levels of intelligence,
it reduces the use and development of the frontal lobes (and of higher cortical capabilities in general).

One quick corollary: if schools or parents or society terrify the children, intentionally or not,
it may have huge implications for the development of the capabilities of the frontal lobes,
and of the cortex in general.  Levels of adrenalin are a crucial variable which needs to be accounted for when we think about education.

That reminds me of a talk I heard, in one of the annual review meetings of the NSF Science of Learning Centers. People asked: "why is US mathematics education so poor compared to
many other countries?" In one study, they observed typical elementary school teachers, shifting form one subject to another. Sheer mention of the word "mathematics" led to an immediate spike
in the levels of adrenalin in the average teacher's bloodstream. Children being responsive...
it is no wonder that learning has been blocked so much.   It reminds me of the sci fi novel Dune, where hey said "Fear is the mind killer." But what of those Indian kids who seem to do better
in math so often? Two weeks ago, at the International Space Development Conference, a friend
who works with Indian schools explained: "A large fraction of that is kids who grew up
in special schools, where they were always told how great they were, and they didn't get ENOUGH
'fear of god' and humility..." Whatever. They did learn things in those schools.

Dr. Arnsted stressed how high levels of adrenalin or stress do get translated into different TYPES
of lower level responses -- sometimes fight or flight, and sometimes just freezing. She described how
she herself fell into a natural adrenalin freezing behavior, which worked quite well when she found herself close to a bear one time in the wild... But can people LEARN to keep their frontal lobes working in the face of stress and fear? (Is that more a subject for future research? And for adults?)

And what IS stress, and how does it relate to fear?

The neural network folks in the audience were a bit puzzled by this. "We don't have global hormones like adrenalin in our models. How can we make sense of this. Is this something we build computers
to be able to AVOID?"

So I got up to explain, and I add a bit here:

"Some of us in the neural network field moved on many years ago, before the PDP books, to
consider engineering designs which are far closer to the brain than the simple feedforward
networks you guys keep saying we are stuck with. We aren't the ones who are stuck. The ones who are stuck are the ones who keep referring to popularized accounts which oversimplify the math which was developed well before the popularized accounts were written.

"The brain actually uses recurrent or reverberatory connections for at least three different things,
each of which needs to be understood on its own terms. There is the time-lagged memory effect.
There is also what I call 'simultaneous' recurrence, like how we focus and gradually grow an understanding of something tricky, like how to 'see' the chessboard we are staring at. And there is also a kind of lower-level memory function, closed to the hard-wired stuff.

"If someone screams at you and really scares you when you are staring at a chessboard, you
can really lose that inner strategic picture you were developing. After the shock, you may have to start all over again, after your adrenalin levels off enough. And nasty chess players do sometimes try to raise the adrenalin level of their opponents. That's the simultaneous recurrence.

"This connects to the real math design as follows.  When we actually design simultaneous recurrent neural networks (to be able to play a good game of chess for example), we face a perpetual dilemma:
to converge quickly to the wrong answer, or to take the time to get to the right answer? Do we "reward" our neural networks based on the quality of their first guess, or the quality of what they come up with after some time to think? (In fact, this issue of "stress" or "tension" is described exactly like this in chapter 3 of the Handbook of Intelligent Control, which is posted at ) There are lower level circuits in the brain which are more feedforward, to provide fast initial guesses about what to do, and others which give better answers but need time to find them. Professor Arnsted appeared delighted that we could provide some level
of functional engineering understanding here, which did fit with what she sees.

Notice, then, that "fear" and "stress" are not the same thing, even if they often occur together.

Of course, "fear" and "hope" are much easier to understand; they are part of
"adaptive critics 101", which I have given endless tutorials on, some posted on my web page.


For those who get to the more detailed paper on "how to build a mouse brain," which
I mentioned in an earlier blog post.... it should be sobering that good mechanisms for
creating and managing "stress" are important even to "VECTOR INTELLIGENCE,"
a level of brain or intelligence far below that higher level we see in the brain of the mouse,
which in my view is much lower in turn that the highest spiritual capabilities of the human mind.
We are not ABOVE this issue of stress; rather, it is part of the path we must cope with and understand, before we can really rise to a full mastery of higher levels.

Best of luck...

Saturday, June 8, 2013

What would you advise the Saudis to do about energy?

A few weeks ago, I was invited to give a presentation on
world energy futures and strategy issues at the World Futures Forum,
in Azerbaijan -- not Saudia Arabia, but a place with some of the same 
stakes in energy. Aimed at serious but high-level futurists and policy makers,
addressing the big picture, bottom line.

For legal and regulatory reasons, I did not accept the offers of business class ticket
and honorarium to give the talk in person. But ... I did do a 12-minute talk (with 5 slides)
by video... so in case anyone is interested, here is what I said: