Become a fan of Slashdot on Facebook

 



Forgot your password?
typodupeerror
×

Comment Donating blood after a disaster (Score 2) 1718

"Posts directing people where and how to give blood have been removed."

While straight-up removal of such posts may not be the best approach, the intent behind such removals is likely honorable.

Donated blood needs to be screened for infectious diseases and otherwise processed before it can be used; it generally takes at least a couple of days before blood from a donor's arm can get to a patient's bedside. The blood that helps the victims of the Orlando massacre isn't the stuff that the Red Cross collects today and tomorrow; it's the blood that was donated last week or the week before. And blood has a limited shelf life--creating a big oversupply now doesn't help unless there's an enormous disaster in the next few weeks.

Donating blood now might make the donor feel good about themselves, but it's not actually a particularly constructive thing to do. If you want to help, put a reminder in your calendar to donate blood in two or three weeks, after this glut has made its way through the system. Or donate blood when the Red Cross (or whichever agency handles blood products in your jurisdiction) indicates a shortage. Better yet, get in the habit of donating blood regularly--help maintain a stable blood supply over the long term.

Comment Re:SJW bullshit (Score 1) 231

I guess no men wrote anything decent this year?

I'm sure that George Miller, Brendan McCarthy, and Nick Lathouris (winners, Ray Bradbury Award for Outstanding Dramatic Presentation) would be surprised to hear you say that.

No they wouldn't be surprised at all. They wrote a movie featuring strong women that was very popular with feminists. They know this is why they got to be the tokens this year.

So you're shifting the goalposts, then? It has to be men writing about men only. Got it.

(And I'm not sure why, even with your special pleading, you think you can ignore the inconvenient fact that men were amply represented among the nominees.)

Comment Re:SJW bullshit (Score 1) 231

I guess no men wrote anything decent this year?

I'm sure that George Miller, Brendan McCarthy, and Nick Lathouris (winners, Ray Bradbury Award for Outstanding Dramatic Presentation) would be surprised to hear you say that.

Or, for that matter, Charles Gannon, Ken Liu, Lawrence Schoen (Best Novel nominees); Eugene Fischer, Usman Malik (Novella nominees); Michael Bishop, Henry Lien (Novelette); David Levine, Sam Miller, Martin Shoemaker (Short Story)....

But since you can't read more than four lines into a Slashdot blurb, I suppose it isn't surprising that you don't know much about good writing.

Comment Re:Arousing (Score 1) 162

It's important to note that by 'arousal', the researchers do not mean sexual arousal.

Though it should be noted that "arousing" only indicates a generally heightened state of awareness or attention.

Indeed, I was about to offer the same note. I presume that the quote from the article (and the paper's title) were deliberately offered without context in order to sound more titillating than they really are.

"Arousal" in this context can also represent nervousness, discomfort, fear,, and reluctance. The sensor is measuring skin conductance (galvanic skin response), which just indicates that there is increased blood flow and/or perspiration.

Comment Re: Article title (Score 4, Informative) 135

Soap doesn't kill germs. All it does is makes oily substances more likely to be pulled along by water than they were before.

Soap certainly kills some germs. There are lots of bacteria and viruses which are vulnerable to the SDS (sodium dodecyl sulfate), a detergent widely used in hand soaps, shampoos, and a bunch of other sudsy consumer products. The detergent disrupts the cell membranes of many bacteria, and it denatures (unfolds) important proteins in many strains of viruses and bacteria.

Sure, the improvements to mechanical cleaning and suspension of oily matter are important, too. And there are certainly some things (spores and other more robust pathogens) which are resistant to SDS and other detergents, particularly at short exposure times. But "soap doesn't kill every germ" is a long way from "soap doesn't kill germs".

Comment Re:Not coming to a sky near -me- (Score 1) 26

I'm totally with you on the lack of naked-eye night-sky access and I definitely don't want to minimize the loss it represents to city-dwelling humanity. I live in a large city way down at the bottom of the Bortle scale, in the center of one of those whited-out you-can't-see-a-thing patches on the light pollution maps. From time to time I'm lucky enough to get away to a little cabin in the woods with impeccable dark skies, but the rest of the time I have to make do with viewing from the parking lot next to my apartment building.

That said - and the article mentions this, but it's worth reiterating - a surprising amount of the sky becomes accessible again for those of us with even basic digital SLRs (and even some of the more fully-featured point-and-shoots). Last January, the nominally-naked-eye comet Lovejoy (C/2014 Q2) was in the sky near the Pleiades. No hope of seeing it with my own eyes, but it was an easy target for just about any lens in my camera bag. It's trivial to capture stars down below ninth magnitude There's a little bit of - a different sort of - magic to being able to pull so much of the night sky out of the muck.

I could probably do some moderately impressive things with binoculars, too, but I'm a bit concerned about what the neighbors would think.

Incidentally, the suggested camera settings provided in the CBC article (ISO 1600, 30 second exposure) may be a bit aggressive for very bright city skies, and will definitely show at least some star trailing. Don't be afraid to play around. My skies start to get too bright if I go beyond ISO 800, f/3.5, 5 s or equivalent. And a five-second exposure is close to the limit if you want to avoid perceptible star trails at a medium-wide focal length.

Comment Re:Near-parabolic? (Score 3, Funny) 26

What the hell does that mean?

If it's parabolic but really really long, "near-hyperbolic" would be a reasonable description -- that's not out of the ordinary for comets.

Presumably it means that its orbit is closed - elliptical - but is only very loosely gravitationally bound--perhaps even more so that most comets. In other words, its velocity is only just shy of escape velocity, hence near-parabolic. Yes, mathematically speaking, that means that its orbit must also be near-hyperbolic; an infinitesimal increase in velocity converts a parabolic path into a hyperbolic one (and an infinitesimal decrease in velocity converts a parabolic path into a long-period ellipse).

Comment Re:"Supposedly"?! (Score 4, Informative) 151

No it's not. Weight energy and volumic energy are two different things. The article does not say which is which.

It's a good thing that the summary (didn't even have to click through to the article) indicates that it's using volumetric energy density for both:

"Sony is developing a new type of battery chemistry that can boost runtimes by 40 percent compared to lithium-ion batteries of the same volume. Sony's batteries use a sulfur compound instead of lithium compounds for the positive electrodes, reportedly allowing for much great energy density. Sulfur batteries can also supposedly be made 30 percent smaller than traditional lithium-ion cells while maintaining the same run times."

Weight - and therefore energy density per unit mass - isn't mentioned or implied.

The grandparent's observation is spot on--the summary is indeed saying exactly the same thing in two different ways. If you can have the same runtime in 30% less volume, you can always get 40% more runtime with the original-sized package. To within a trivial rounding error, 140% and 70% are reciprocals; they're just saying "40% improvement in volumetric energy density".

Comment Re:They didn't get it perfect. Must be useless (Score 1) 88

Just for clarification from TFA, they did not disqualify over 1,000 candidates. What they found was: 67 Binary Stars and 3 Brown Dwarfs out of the 129 candidates they actually looked at.

That seems like an awfully small sample size to me, but hey I'm not a scientist.

Actually, if that represents a random selection from their initial pool of candidates - that is, if they didn't do any initial pre-sorting to enrich their selection for stars over planets - then that's a reasonable sample size. As long as their sample was random, it's actually the absolute number of stars in their sample that matters. The standard deviation in their estimate of the number of non-planets goes as roughly the square root of the number of non-planets in the sample. We'll say the square root of 67 is about 8, so there's an estimated error of plus-or-minus 8 out of 129--about 6%.

If, before an election, you do a telephone survey of 1000 people, you'll be able to estimate the election's outcome with about the same confidence whether the country has a hundred thousand or a hundred million voters. Essentially the same statistical principle.

If that sounds weird, try it with inanimate objects instead. If I pull 100 jelly beans from a large and well-shaken bag, and 50 happen to be red, then I'm going to be pretty confident that roughly half of all the jelly beans are red--no matter how big the bag is. If I pull a 100 planet candidates from the Kepler survey and 50 turn out to be stars, then I'm going to be pretty confident that roughly half of the planet candidates are stars--no matter how big the list of Kepler candidates is.

Comment Re:Missing information... (Score 2) 393

If 40% of those university graduates are still overqualified by their mid-thirties, they've already been typecast by their experience in the 25-35 range.

That's certainly a problem with the data provided--it bundles together the fresh-out-of-school 25-year-olds with the decade-plus-in-the-workforce 34-year-olds. There's a lack of resolution. It could be that 40% of 25-year-olds and 40% of 34-year-olds are "overqualified". Or it could be that 60% in the 25-29 age group are overqualified, and just 20% of the 30-34 bracket.

Actually, that brings to mind another confounder to the interpretation of these data. As more young people get more years of formal education (3-year college diploma to 4- or 5-year bachelor's degree to 7-year bachelor-plus-master's degree) they enter the workforce later. A 25-year-old with a high school diploma might have been working for 7 years (and is also more likely to be working in a job for which they are not "overqualified" by their lower level of formal educational attainment). A 25-year-old with a master's degree might have graduated this summer and could still be job-hunting.

Slashdot Top Deals

Is your job running? You'd better go catch it!

Working...