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March 2

Geography of glioblastoma multiforme.

I am wondering if this information exists somewhere. Thanks.--AboutFace 22 (talk) 03:34, 2 March 2014 (UTC)[reply]

"Coffin corner" flight ops

Is it true that as an aircraft approaches its service ceiling, its V(x) increases? And as for V(y), does it decrease as the plane climbs toward its service ceiling, or does it stay the same? (Just to clarify, my question is in terms of indicated airspeed, not true airspeed.) 24.5.122.13 (talk) 04:48, 2 March 2014 (UTC)[reply]

Well, air gets thinner up higher, which will allow planes to move horizontally faster (V(x)), but provides less lift at a given speed, limiting the climb rate (V(y)). Of course, V(y) could also describe the descent rate, and the flight speed is dependent on many other factors, as well, such as engine speed, flap and aileron configurations, etc. StuRat (talk) 17:44, 2 March 2014 (UTC)[reply]

No, V(y) cannot describe the descent rate, because it represents the best rate-of-climb speed, and V(x) describes the best angle-of-climb speed -- see V speeds for the definitions of V(x) and V(y). 24.5.122.13 (talk) 01:03, 3 March 2014 (UTC)[reply]

OK, I wasn't using the aeronautical sense, I was using them in a general engineering sense, where V(x) means the horizontal component of velocity and V(y) means the vertical component. StuRat (talk) 19:42, 4 March 2014 (UTC)[reply]

Have you tried Flight envelope article yet? 71.20.250.51 (talk) 03:31, 3 March 2014 (UTC)[reply]

Sure I did, but it does NOT address how V(x) or V(y) change with altitude. 24.5.122.13 (talk) 05:13, 3 March 2014 (UTC)[reply]

I haven't had any luck either, but conjecture suggests the answer is "yes" to your original query; however, we need to find facts from reliable source(s). If found, "somebody" (hint, hint) should clarify this in the appropriate article(s). ~E:71.20.250.51 (talk) 07:34, 3 March 2014 (UTC)[reply]

I'm pretty sure that my original conjecture was correct as far as V(x) is concerned (I can tell as much from power curve data), but I'm not quite sure what happens to V(y). 24.5.122.13 (talk) 07:47, 3 March 2014 (UTC)[reply]

I suspect the V_(y) question largely depends on aircraft type. For example, a commercial heavy still requires lift vector from wings as it approaches ceiling, but in general, for fighters that is less important; in effect, they rely on the thrust vector. At altitude, the wings are essentially control surfaces; the 100-series fighters had a reputation of dropping like a brick if power was lost. — Preceding conjecture added by 71.20.250.51 (talk) modified:18:02, 3 March 2014 (UTC)[reply]

A better metric might be angle of attack. Vx<Vy at the service ceiling as you must have at least 100fpm climb at the servvice. at max altitude, Vx=Vy. There is no climb left. Vx increase with altitude (flattens out to not stall), Vy decreases with altitude (excess power reduces as aircraft gains altitude). --DHeyward (talk) 09:50, 4 March 2014 (UTC)[reply]

Like I suspected. Thanks! 24.5.122.13 (talk) 07:08, 5 March 2014 (UTC)[reply]

Immune system and infectious disease

It has been known that some people's immune systems can clear infectious diseases before they cause symptoms or while it is only causing mild symptoms. This tends to be for infectious diseases transmitted through the air, surfaces or food but what about for those which are transmitted sexually? Can the same happen for these? Clover345 (talk) 11:14, 2 March 2014 (UTC)[reply]

Here is a list of asymptomatic STDs, which may go some way to answering your question.

Different diseases have different thresholds for exposure to create a self-sustaining infection. Many of our individual articles on diseases make mention of these. I don't know if there's a consensus about why. But some diseases require a rather large number of antigen exposure, while others require very little. This isn't the same, but it's similar to the OP question. Shadowjams (talk) 18:28, 2 March 2014 (UTC)[reply]

Hi

Please see Talk:Resistant_starch#As_functional_fiber. Good day. Ben-Natan (talk) 12:26, 2 March 2014 (UTC)[reply]

The relevance of that to this reference desk is......? The Rambling Man (talk) 16:41, 2 March 2014 (UTC)[reply]

Sound of freezing rain

My house has been getting freezing rain at a rate that's taken my car (parked; I'm not typing while driving :-) from clean to thoroughly covered in half an hour. I knew that it had arrived when I first heard the "clicking" sound typical of freezing rain — but why? Why does freezing rain produce this sound? No answer in glaze ice, ice storm, or freezing rain. Nyttend (talk) 13:45, 2 March 2014 (UTC)[reply]

If it's making a clicking sound, I'd say it was already partially frozen when it hit (sleet). Freezing rain normally means it's all liquid when it strikes, but then freezes when it lands on objects below freezing temperature. Of course, during one storm you often get both, as well as many other forms of precipitation. StuRat (talk) 17:31, 2 March 2014 (UTC)[reply]

Related note

According to ice storm, Most ice storms are in the northeastern US, but damaging storms have occurred farther south. Is this really true? I can't imagine why it would be a primarily American thing, i.e. why "most" of them would be in a tiny part of the world. Should it perhaps read most American ice storms are in the northeastern US...? Nyttend (talk) 13:45, 2 March 2014 (UTC)[reply]

What is this thing you call the world? Is it near Amarillo? μηδείς (talk) 16:33, 2 March 2014 (UTC)[reply]

It's most likely an indication that most of our articles are US-centric, something we're all used to but can't seem to fix. The Rambling Man (talk) 16:35, 2 March 2014 (UTC)[reply]

And you reported here rather than fixing it because.... --Jayron32 03:26, 3 March 2014 (UTC)[reply]

BeFeC

Why isn't beryllium-steel alloy in the Alloy steel article? It's the lightest usable metallic material, isn't it? Usable for being in air and stuff. Sagittarian Milky Way (talk) 17:28, 2 March 2014 (UTC)[reply]

Find a source, then be bold and add it yourself. StuRat (talk) 17:37, 2 March 2014 (UTC)[reply]

I've never heard of it. According to [1], beryllium is not very soluble in iron at temperatures < 600 C. I doubt you'd be able to add more than a couple percent without it forming other compounds. Beryllium is light, but it's also expensive (2x as much as Mg and 10x as much as Al) and toxic. Mr.Z-man 20:20, 2 March 2014 (UTC)[reply]

It's been over a decade, I might've misremembered the combination with Al or even Ti or Mg. And the article on the element states that it's unreactive enough to be used pure in rocket nozzles, so maybe /that's/ the lightest metallic material that's been used in air. (Yes, I was aware that you've got a demanding application if you need something this toxic, fire hazardous and expensive to save a little weight) Sagittarian Milky Way (talk) 00:36, 3 March 2014 (UTC)[reply]

Is the ARKYD Kickstarter satellite telescope in orbit now?

If so, whose rocket launched it into orbit? 75.75.42.89 (talk) 19:06, 2 March 2014 (UTC)[reply]

Please, see Planetary Resources. Ruslik_Zero 19:27, 2 March 2014 (UTC)[reply]

I saw a lot about their satellites in that article, but didn't see anything stating who puts them into orbit for them. 75.75.42.89 (talk) 19:38, 2 March 2014 (UTC)[reply]

According to this it's not due to launch until 2015. Richerman (talk) 21:22, 2 March 2014 (UTC)[reply]

So the answer from that source is "Virgin Galactic and Planetary Resources have a previously established relationship, with Planetary planning to launch Arkyd-100 space telescopes into orbit using the to-be-built LauncherOne air launched booster when it becomes available." 75.75.42.89 (talk) 23:13, 2 March 2014 (UTC)[reply]

Which is also the answer given in our article which hasn't been modified since 7 February "In July 2012, Planetary Resources announced an agreement with Virgin Galactic to enable multiple launch opportunities for its series of spacecraft on LauncherOne starting with the Arkyd-100 series of space telescopes." The 2015 date is also given in our article "The near-term attempt to validate and mature the technology is planned to launch in April 2014, before launch and flight test of the Arkyd-100 in 2015.[24]" Our article also covers other details of their current and future plans e.g. "company is contracting with NanoRacks to take the A3 to the International Space Station, where it would be released from the airlock in the Kibo module" Nil Einne (talk) 12:44, 3 March 2014 (UTC)[reply]

Aquifers

Where can I find out exactly which aquifers supply Lebanon, CT? — Preceding unsigned comment added by 99.146.126.108 (talk) 19:37, 2 March 2014 (UTC)[reply]

The only major groundwater supply in Connecticut is known as the "Early Mesozoic basin aquifer", see here, it's the turquoise colored streaks along the east coast of the U.S.; said aquifer seems to lie mostly in the Connecticut River Valley. Lebanon, Connecticut lies outside this area, so there does not appear to be large groundwater supplies in that area. Water supplies from that town are likely from resevoirs, see here for a list of reservoirs in the state of Connecticut. Perhaps find one near Lebanon. --Jayron32 03:25, 3 March 2014 (UTC)[reply]

I am not sure what aquifer or aquifers serve Lebanon, CT< jayron, but the map you have provided is a very general source which shows the three main aquifers in CT, the turqouise one being one of those three. There are plenty of smaller separate aquifers the size of municipalities or so. Any search for "connecticut aquifer map" will show this. For example, see this map. μηδείς (talk) 05:12, 3 March 2014 (UTC)[reply]

Good find! It should be noted that all of that map labeled "crystalline rock" is basically non-Aquifer rock. --Jayron32 13:16, 3 March 2014 (UTC)[reply]

You could check with the town government, who operate a Water Pollution Control Authority. It sounds like drinking water supply is authorized and maintained by a different level of government, presumably by your state or county or regional water authority. For example, the Regional Water Authority (of South Central Connecticutt) looks like its distribution ends west of your county; the South East Water Authority might cover you. If you use municipal supply, to whom do you pay a water bill? If you use well-water, you might have to ask around a little more - which contractors drilled or maintenanced your well? Which county or other government (if any) performs safety or health checks on your well? Nimur (talk) 15:58, 3 March 2014 (UTC)[reply]

Since 9/11, inquiries like this made by people with no legitimate reason are looked into as possible signs of scouting for terrorist goals. People have been investigated for taking pictures of, or on reservoirs. μηδείς (talk) 18:24, 3 March 2014 (UTC)[reply]

I hope you're wrong about this, but in this spy-crazy world... I can't swear to that. Though it beats me why a terrorist would care where the aquifer water ends up, as long as he can contaminate it. By contrast, a keen awareness by townspeople of where their water comes from could be very useful for protecting life and property. Wnt (talk) 20:05, 3 March 2014 (UTC)[reply]

I spent a minute googling for investigations of people at aquifers expecting to get hits on NYC's upstate reservoirs, but got hits mostly on the Quabbin reservoir. I should apologize, since I have been mentioning reservoirs and aquifers in the same breath while they are not the same thing. But there are various aquifer protection areas, trapsing around which might draw suspicion. μηδείς (talk) 18:16, 4 March 2014 (UTC)[reply]