Prediction of really dynamic events - the long term weather, economics, etc - is really hard.

What you can do, scientifically, is analyze how different factors affect each other over time. You can predict that conditions are ripe for a type of event (inflation, unemployment spike, a market bubble, recession, etc). You can predict the course of an economic shift based on inputs (bailouts, government investment, policy changes, money supply changes, consumer confidence and employment, etc).

Being able to say "The bond market? It's going to collapse on Tuesday," is really hard.

Chastising economists because the economy is too complicated for us to do mid to long term projections accurately yet is unreasonable. They understand at micro, intermediate, macro, and international levels. They can show interactions and trends and make useful predictions. But they can't model the whole thing on an ongoing basis.

The Wikipedia article is intentionally not useful for designing anything.

However, we do have an online textbook (at roughly upper-division engineering/physics college student difficulty level) on the subject:
    http://www.nuclearweaponarchive.org/Nwfaq/Nfaq0.html

In terms of what's been published online -

* There's a book with precise dimensional drawings and measurements on the Little Boy type Uranium gun type bomb. Not online, but purchasable at Amazon. It's not "a blueprint" but any competent draftsman / mechanical engineer could produce blueprints to build from, given the book.

* The dimensions and materials of all the layers of the Fat Man / Mark 1 type nuclear weapons are published in numerous sources. The precise shape of the lens in the outer layer has not been, though a rough back-of-the-envelope version of the equation for the lens shape is published. A precise and buildable lens shape would require someone with a fair talent in explosives engineering and shockwave engineering, especially someone aware of what the published equation left out, but the Fat Man design is fundamentally so brick-solid-simple that one could get the lens fairly imprecise and still have a functional weapon.

Some effort has gone into not actively publishing newer weapon design details in public. But that's not nearly the same as "they're not out". A number of more modern weapons are understood to at least close to the level Fat Man and Little Boy are. There are accurate internal component photos declassified for some weapons and parts. There are detailed hands-on descriptions of some parts, by people who worked on them. Check out the Wikipedia article on the B61 bomb, for example; the fission and fusion components were shown in a declassified film (but not the explosives to compress the fission parts).

Not for nuclear weapon design information. That's "Restricted Data", see DOE classification rules. Accessed with a DOD TS-CNWDI (Top Secret - Critical Nuclear Wepon Design Information) or DOE Q-clearance plus appropriate Sigma compartment clearances for the specifics you're looking at.

No, it's not.

Differential backups are taking a single filesystem, seeing what changed (either at the file level (whole changed/updated/new files) or block level (changed blocks within files).

Block level deduplication is noticing that the storage appliance on which you back up 100 desktops and 10 servers has 50 copies of the same version of each data block in each Microsoft OS file from XP, 25 from Win 7, and 35 from Fedora, and only storing 1 copy of each of those blocks rather than 100 separate ones. It's returning those blocks to the usable storage pool and remapping without having to "compress" anything, not having to rewrite the backup data images, etc. It's just saying "This is block 3 of the binary for Internet Explorer 8, and I already have a copy of that", for each and every common block out there.

You still have to upload the blocks, and the system still needs to scan them to notice the duplication, but it's a lot more than "oh, compression".

Thirded. Data Domain (now part of EMC) really started the commercial use of this...

The basic architecture should be cheap to fabricate in bulk. It's lines of wires, a layer running in one direction, a thin film of the memristive material, then a layer of wires on top running at right angles. Every intersection point is a bit.

DRAMs involve all sorts of careful operations to create a trench or stack, fill it with a capacitor, run the lines in and out, etc. Much more complicated on a per-bit basis. Many more things can go wrong. Memristors are pretty much the simplest to implement circuit element I've seen come along in a long long time.

The key questions are performance. How many write cycles can the fabbed chips survive before bits start going bad / getting stuck? Typical MLC fash is 10-100 thousand, very good SLC flash 100k to 1m cycles. This is not enough that you can ignore the write lifetime issues, and today's SSDs will wear out if written very actively over long periods of time.

Memristors (and Phase-Change RAM, and some of the other options out there for new non-volatile RAM) offer potentially very long life. But it's not clear if the produced chips will be 1m and up, 10m, 100m, or what.

At some point the device's overall lifetime is shorter than the wearout rate and you stop caring about wear leveling, etc. You just detect bit errors and map around them, and a few bit errors happen over device lifecycles. The wear leveling now used is a big deal on SSDs and a major factor in their performance (or not).

Also very important is how fast the chips are. Should be fast - you fire a short AC pulse down one word line, read the bits out the bit lines. Either the resistor resists or it doesn't. Word line enable transistor delays and read amp sensing delays of less than 10x transistor cycle time at a given fab size/process are likely, which is pretty good. Potentially this is faster than DRAM, more like SRAM, but not all fab / design approaches would get there (and not all potential fab processes).

Secondarily, how fast is a write cycle. SRAM writes very very quickly. DRAM reasonably quickly. Memristor? Should be fast, but there are current and material breakdown concerns.

Fundamentally, we need to see the chips. When we see chip spec sheets, it tells us how useful these are.

It could range from "replaces FLASH at certain densities or write life requirements" to "replaces all FLASH completely" to "replaces a lot of DRAM" to "becomes the only memory in use between CPU caches and hard disks". Potentially, it could be cheap enough to even replace hard disks.

We've had computers in recent memory (1980s, early 1990s) which were operating without all the data cache tiers we now have to deal with in computer architecture. Large chunks of computer architecture now is nearly all about efficiently managing the tiered data storage - CPU registers to CPU cache, CPU cache to main memory, main memory to disk. There are factors of 10 speed difference or more between each tier (more from DRAM to disk). Fast reliable nonvolatile RAM could flatten that all out a lot. FLASH isn't good enough due to write lifecycle limits. Memristors, if the performance comes in near the top of the possible range, could. Will they? I'm not working for HP or Hyundai, I don't know what they've got. I'm preparing for designing some systems which could flatten things, who knows if we'll actually get there with this tech. It could be a game changer, or it could be just another technology on the block.

The sad part is, datacenter power people are now on the "avoid stranded power" trip trying to increase power efficiency (UPSes and PDUs running at 80% are much more efficient than those running at 50%). They don't seem to understand or be willing to provision to support one leg actually failing completely.

They're handling the "one server out of tens has a power supply failure on one leg" failure, but not the "the whole rack flips to only using B power due to X"...

For backed up to tape storage? Storage replicated to another, remote datacenter? Snapshotted at regular intervals?

SAN storage? NAS? Direct attach? On arrays with 10 drives, 100 drives, or 1000 drives?

Fast SAS or FC drives? SATA arrays? 5400 RPM? 7200? 10k? 15k?

If you're paying $360/GB/yr for low end storage that sucks. For very high end, with replication and snapshots and the fastest drives and so forth, that's pretty high, but not an order of magnitude high.

Standard interfaces are great. DIMMs are standard interfaces, usually only 1 device hop from the CPU, as opposed to drives which are often 8 or more, and several orders of magnitude of slowness away. Close enables fast in computer architecture.

Regarding the moving drives/dead system question... What's the hard part?
You just move the "drive DIMM"...

The hot new solid state non-volatile memory technologies are phase-change memory (PRAM), memristors, ferroelectric RAM, resistive RAM.

Some of these technologies are much more area-efficient than Flash, and will stack in pseudo-3D chips reasonably well (memristors in particular should stack in full 3-D arrays very efficiently...).

The general observation that disks have the lead right now is true, but the other technologies close a lot of the gap, and the growth curves look very similar after that. Who knows if it ever gets cheap enough to completely replace disks in our lifetimes, but there is hope of seeing that.

That does entirely change the game on system architecture. Disks are slow and far away from the CPU. Solid state memory can be as close or nearly as close as DRAM, and if it doesn't require a lot of handholding on lifecycle management (wear rates etc - Flash is horrible here) then can be used and managed as a simple byte or block array rather than the whole "filesystem" crap we now use. We still may want POSIX like abstractions for parts of storage management, but life is so much easier if the back end store is just a block array we read/write than if it's really a spinning disk, behind a cache, behind a controller, behind a SATA/SAS bus, behind a controller, behind a PCI bus, behind a southbridge, ....

[citation needed]

One of my parents was a government contracts attorney, who did it professionally and taught it part time at local law schools.

Nobody likes the US Government as a customer. It's by far the most annoying customer for any tech company. The contracts will be 2-10x as hard to administer, 2-10x as much overhead as commercial contracts, and you get sued a lot more (usually over the proposals/bidding, but it's still a suit).

But, assuming it is, can you realistically charge someone with manslaughter for deaths caused by a natural disaster?

Sure, under some circumstances, if the disaster was predictable (flood, earthquake, landslide, hurricane) and someone didn't take normal or minimum non-neglegent steps to avoid putting others in danger, or lied about being ready.

Lying about your building being seismically upgraded, for example, and then having it fall down.

The scientists' correct response is "There's a 100% chance of multiple earthquakes in this location over the next 1000 years. We have no way of knowing when or how many at this time. Live in unreinforced masonry buildings at your own risk."

I have an excellent idea of how multistage clinical trials work, and why. I have family members who were strongly affected by well known drugs that failed to be safe in general practice.

The specific technique in question has worked in all the mammals it's been tried in. That doesn't mean you can just skip ahead to doing it in humans on large scale without trials, no. But it was having problems getting approval to get the trials started, in no small part because of the insane federal government stem cell regulations from the previous administration. T his was particularly offensive because it entirely uses the patient's own stem cells (you liposuction some body fat to extract the stem cells from), and had nothing to do with embryonic stem cells.

I wouldn't be complaining if it had been winding its way through approval. The FDA had threatened vets who were doing this and who had openly discussed doing a less rigorous Phase 0 study on themselves as human test subjects. Admittedly that's not nearly as rigorous as a fully rigorous Phase 0, but it will at least give you some bounds on serious side effects.

As an aside on the normal pharmaceutical testing protocol, there are cases where severe or uniformly fatal diseases exist and people will die anyways. It took a long time to get the FDA to approve shorter protocols and widening Phase III trials to allow a chance of saving some dying patients with the study phase drugs; some of the AIDS drugs were the catalytic agent for that change. There are some cases where even a worst case - the drug kills everyone who takes it - would not be necessarily a societal or individual moral disaster compared to the underlying diseases.

You should have enough risk mitigation from Phase 0 and Phase 1 that a wider Phase 2 in many acute or terminal conditions is entirely called for. A number of medical ethicists have commented that liability risks (someone will sue, even if their loved one would have died within a month anyways) and FDA inertia are holding back a number of treatments that fall into these categories.

Just to be clear - The joint repair stem cells aren't relevant to that question - joint injuries and damage are a quality of life not survival disease.

The one place where stem cell treatment seems to have good scientific basis - joint repair, where stem cells are centrifuged out of fat cells and injected into the joint - is stuck in FDA human trials hell in the US.

It works great in a number of animals, and is available for dogs and horses (at least) via vets.

People? Nope. Go fish.

There's no reason for him to go into a high security prison. It costs more for the feds to hold high security prisoners, he's never been accused of violence, he seems to be a low risk to guards or other prisoners. Him being a foreign national doesn't really play into it.

His supporters in England are using the "He could theoretically be sentenced to high-security!" as a scare tactic, along with a number of others. Sure, he could be - they could send him to SuperMax in Colorado. But they won't, because it's expensive and there's nothing he's done that justifies anything more than minimum security.