Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
Get HideMyAss! VPN, PC Mag's Top 10 VPNs of 2016 for 55% off for a Limited Time ×

Comment Re:Radiation (Score 1) 412

Pure water will not accumulate radioactivity. With one exception, there is no reaction with hydrogen or oxygen to make a long term radioactive nucleus. 16O+n->17O (stable). 17O+n->18O (stable). Very rare 18O+n-> 19O, half-life 26s. 16O+p->17F, half-life 65s. Etc.

The only exception is 2H+n -> 3H (tritium, half-life 12.3 years) but the cross section for this is very small, and H2 (deuterium) has very low concentration (0.01%) in ordinary water.

So leave your irradiated pure water for half an hour out of radiation, and it will be fine.

Contaminants in the water could accumulate long term radioactivity. If this is enough to be a problem (I'd bet it isn't), you'd need to purify the water before use.

Comment I hit this limit once in the Unix world (Score 1) 260

I was at a company which developed a large CRM application and I was the person who tarred up software updates to send to sites. A small part of the application was in Java, and the Java programmers were enamoured with class names which emphasized descriptiveness over brevity. We ended up with some files where path+filename exceeded 255 characters, and tar broke. My fix was to tell the programmers to shorten their damn file and directory names. (This was about 15 years ago, and it would have been Gnu tar. )

Comment Re:sequence it (Score 1) 287

My understanding is that this has already been done: smallpox has been sequenced, and if all samples were destroyed and then for some reason we really needed to have smallpox again, we could reconstruct it. It eight years since scientists created a synthetic bacterial genome of 580,000 base pairs. Smallpox is (according to Wikipedia) 186,000 base pairs.

Comment Re:Not all eukaryota have mitochondria (Score 4, Informative) 48

This was my understanding, but TFA says:

For decades, researchers have tried to find eukaryotic cells that don't have mitochondria --- and for a while they thought they'd found some. One example is Giardia, a human gut parasite that causes diarrhea. It was considered to be a kind of living fossil because it had a nucleus but didn't seem to have acquired mitochondria. But additional studies on Giardia and other microbes showed that actually, the mitochondria were there.

"It turned out that all of them actually had some kind of remnant mitochondrion," says Karnkowska, who notes that mitochondria perform key jobs in the cell beyond just generating power.

I figure their knowledge is more compete and up to date than mine.

Comment Re:Looking in the wrong place for emissions cuts (Score 1) 100

Thanks for that analysis. I bow to your superior knowledge.

Humans for safety: "We're talking about miles of track that cross public roadways with children on bikes." The human on board can't do anything useful if a kid crosses in front of their train (it takes hundreds of meters to stop), so this one is a non-issue.

Comment Re:Looking in the wrong place for emissions cuts (Score 4, Interesting) 100

So ideally for a freight rail system we want high throughput, short delivery times, cheap, and running to/from convenient nearby locations.

Breaking this down further, it suggests we want
* Small trains (lowers latency - less time to wait for a train going to your destination. Removes/reduces need for transferring cargo between trains by allowing point-to-point service, so long as the 'point's are train stations.)
* Autonomous (required by 'small trains' and 'cheap')
* Handles congestion well (for high throughput with lots of small trains)
* Fast
* Moderately priced infrastructure.
* High density of train stations around the country
I.e. something like an internet for shipping containers.

Hyperloop gives us 'fast', but fails on infrastructure price, fails at least initially on density of stations, and congestion may be problematic. Starting with the existing rail network and moving to more automation and smaller trains and solving some congestion problems (perhaps the hardest bit) gives everything but 'fast', but for many purposes is 'fast enough'.

It still needs to be competitive compared to autonomous trucks.

TL;DR: I agree.

Comment Re:1050 and 1040 (Score 1) 142

With a bit more research:
Compared to 1080, 1050 has 2/5 as many cores and about 5/8 the clock speed. 1080 has design thermal power of 180W. I don't remember if power is proportional to clock, but if it is, 1050 should have about 1/4 the power draw of a 1080, which puts it at 45W which won't require a power connector and is easy to passively cool, but possibly passive cards won't be available at launch. 1040 would be about 28W (expect fanless to be the norm), and 1060 about 62W (where a power connector might be required, and we might eventually get passive cooling but not real soon.)

If power is a higher power of clock (eg. clock speed squared) then the numbers get even better.

Comment 1050 and 1040 (Score 2) 142

I like my computers very quiet, so my rule of thumb (sometimes violated) is buy the best GPU available which is passively cooled and needs no extra power connector.

I only found one page about the GTX 1050 or GTX 1040. This gives expected release date 2016Q3. However they don't give power consumption (critical for my purposes - I'd be looking for a maximum of about 60W) nor do the numbers they quote give me much idea of how much faster it will be than (say) a GTX 750, which so far as I know is the current best quiet GPU.

Comment SpaceX ownership (Score 1) 119

This mission seems very hard to justify from a commercial view point.

Wikipedia says
"As of May 2012, SpaceX had operated on total funding of approximately $1 billion in its first ten years of operation. Of this, private equity provided about $200M, with Musk investing approximately $100M and other investors having put in about $100M."

So (as of four years ago) Musk only owns about 50% of SpaceX, so it isn't his plaything to do with as he wishes. How is this squared with the other investors?

Slashdot Top Deals

Stinginess with privileges is kindness in disguise. -- Guide to VAX/VMS Security, Sep. 1984

Working...