Science desk
< February 15	<< Jan \| February \| Mar >>	February 17 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

February 16[edit]

Genus species[edit]

Perhaps kinda RD/L, but: is there a term for a critter for whom the genus name is also the species name? Bufo bufo, for example, or iguana iguana, or gorilla gorilla? --jpgordon^{::==( o )} 00:16, 16 February 2015 (UTC)[reply]

Not 100% of the time, but these are usually the Type species. Some type species do not have identical species names to genus names, but AFAIK, the converse is more ocften true: if the names match, then it is usually the type species. --Jayron 32 00:35, 16 February 2015 (UTC)[reply]

See tautonym. (Not a term for a kind of critter, though, but one for that kind of Linnean binomial.) Deor (talk) 01:00, 16 February 2015 (UTC)[reply]

This was discussed here about 2 years ago, and we came up with a very long list. search the archives for "tautonym" and my Greek signature (I started the thread). μηδείς (talk) 01:29, 16 February 2015 (UTC)[reply]

Here's the thread: https://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Science/2012_September_24#Black_rat_taxonomy μηδείς (talk) 04:12, 16 February 2015 (UTC)[reply]

Such as Octopus octopus. Also, the great white shark is Carcharodon carcharias. Is the species name a variant on the genus name? ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:02, 16 February 2015 (UTC)[reply]

In the case of the great white, its name means sharp-toothed maneater. The karkhar root is found in each word. μηδείς (talk) 05:18, 16 February 2015 (UTC)[reply]

So the root karchar means both 'sharp' and 'maneater'? —Tamfang (talk) 09:14, 16 February 2015 (UTC)[reply]

According to EO, karkhar- means "sharp", adj form karkharos, and by combination with odon- "tooth" we get Carcharodon, "sharp toothed". Carcharias is a word derived from the same root meaning maneating. An imperfect analogy would be if we called them something like "Sharptoothed sharpies".

The word seems limited to Greek, and OR implies it either a direct borrowing from outside greek, and imitative root, or a pre-Greek ghar-ghar > karkhar. Ghar- is not a known PIE root, although, interestingly, it would likely have become "gar" in English (a sharp-toothed predatory fish more common to the Germans than the Shark).

Yet the normal derivation for the garfish is from *ghaiso- "spear".(Calvert Watkins), so this connection is my speculation. μηδείς (talk) 18:02, 16 February 2015 (UTC)[reply]

horseshoe crabs and their medical products[edit]

I read about the horseshoe crabs and their medical products. I'm looking for a generic name or commercial name of their products or antibiotics. Thanks. 149.78.227.128 (talk) 02:11, 16 February 2015 (UTC)[reply]

You can try limulus amebocyte lysate or "LAL test". Dragons flight (talk) 18:14, 16 February 2015 (UTC)[reply]

cesium-137 Question[edit]

Hello Wikipedia

I wonder why only the foreign accidents are discussed in the cesium 137 when we have accidents here in USA. Santa Susana located in California was a big accident.

http://www.latimes.com/business/hiltzik/la-fi-hiltzik-20140613-column.html#page=1

http://www.latimes.com/business/hiltzik/la-fi-hiltzik-20140613-column.html#page=1 — Preceding unsigned comment added by 2602:306:BC27:E060:58E6:FE3D:6167:F8E6 (talk) 03:21, 16 February 2015 (UTC)[reply]

Because you (yes YOU are to blame) didn't update the articles. Wikipedia only exists because people who care add information to it. If you find information you care about is not in Wikipedia, you literally have no one else to blame except yourself that it isn't in Wikipedia. So, we're all eagerly awaiting your additions to Wikipedia. What are you waiting for. Get on it. --Jayron 32 03:34, 16 February 2015 (UTC)[reply]

When someone uses terms such as "foreign" and "here in the US/USA" in a post it is certain proof that they are a victim of the delusion that this website is "usa.wikipedia.org". There is no "here" or "foreign" on WP. Roger (Dodger67) (talk) 06:34, 17 February 2015 (UTC)[reply]

Please assume good faith. If I say "here in Canada" I am not under the delusion that WP is about Canada. --70.49.169.244 (talk) 14:45, 17 February 2015 (UTC)[reply]

Species ID[edit]

Can some one please identify this species. It was taken in Hyderabad, India. Nikhil (talk) 03:43, 16 February 2015 (UTC)[reply]

Euphorbia milii, the Crown-of-Thorns, (pictured left). See page on commons, and the gallery of forms at the species's article. There are hundreds of species of Euphorbias, and a dozen varieties of this species. μηδείς (talk) 04:13, 16 February 2015 (UTC)[reply]
- Thank you so much for your prompt response! Nikhil (talk) 04:48, 16 February 2015 (UTC)[reply]

Our pleasure. μηδείς (talk) 22:31, 16 February 2015 (UTC)[reply]

What determines the direction of movement in a Rotor ship?[edit]

If a cylinder is oriented vertically and spinning clockwise or anti-clockwise, why wouldn't it move the ship backwards?--Fend 83 (talk) 14:37, 16 February 2015 (UTC)[reply]

Firstly, these craft are essentially powered by the wind - like a sailing ship. They merely replace the sail with a spinning cylinder. The cylinder produces a force that's at roughly right angles to the airflow, using the Magnus effect. (See image at right) Spinning the cylinder effectively speeds up the airflow on one side of the cylinder, while slowing it down on the other - and that's what creates the force at right angles to the airflow. If the wind is blowing from the left, and the cylinder is spinning clockwise, then the thrust will be forwards. If the cylinder is spinning counter-clockwise, with the wind coming from the left, then there will be a rearward thrust. But if the wind were coming from the right, the reverse would be the case. So a part of what makes these ships work is the ability to alter the direction of rotation of the cylinders depending on the wind direction. A rotorcraft has to be piloted much like a sailing ship - with a keel to enable it to sail at angles closer to the wind, and a requirement to tack in order to sail directly into the wind.

If there were no wind whatever, then spinning the cylinder would have no effect (other than to cause the entire ship to slowly spin in the opposite direction!)...and it wouldn't matter which way the cylinder were rotated.

SteveBaker (talk) 15:03, 16 February 2015 (UTC)[reply]

What is the advantage of Wi-Fi before GSM?[edit]

Is it right the fact that high-frequency electromagnetic radio waves always had more high kinetic inertia (energy) than the low-frequency electromagnetic radio waves?--85.141.234.70 (talk) 16:15, 16 February 2015 (UTC)[reply]

WiFi is only effective over relatively short distances, and doesn't pass through walls very well. That means that when you use a WiFi transmitter, your signal isn't going to interfere with those of people in adjacent buildings (or at least not by much). This is limiting, because you can't (for example) use your WiFi laptop to talk to your printer at home while you are at work, 10 miles away...but it does mean that a LOT of people can share that frequency band without problems. GSM on the other hand has a much longer range - which makes it useful for mobile phones. The downside is that the use of that frequency has to be heavily regulated and you can't have everyone using it at the same time.

There isn't inherently more energy in one frequency than another - it's just that the legal requirements for using those frequency bands are different, and the distance that a signal will travel depends on both the energy AND the frequency. Low frequency signals can travel very long distances with little power. High frequencies need more power to cover the same distance. High frequency signals are also capable of carrying more information than low frequencies - which is also important in telephony and computing applications.

SteveBaker (talk) 16:38, 16 February 2015 (UTC)[reply]

But there is more energy in high frequencies photons (E=hv where E is energy, h is Planck's constant and the Greek letter ν (nu) is the photon's frequency). Dja1979 (talk) 17:23, 16 February 2015 (UTC)[reply]

True - but what stops you from just sending more photons? There is nothing inherently more energetic about radio signals at one frequency versus another. SteveBaker (talk) 15:01, 17 February 2015 (UTC)[reply]

Very thanks for you SteveBaker, Did I understand correctly that the satellite (sputnik) Wi-Fi did not exist, there's been only satellite (sputnik) GSM?--83.237.241.65 (talk) 17:34, 16 February 2015 (UTC)[reply]

GSM is a specific set of technologies and radio frequencies used for cell phones. Neither GSM nor Wifi existed at the time of Sputnik (1957). GSM was introduced in the 1980s, while modern Wifi dates to the 1990s. GSM reaches much farther than Wifi, but it is not designed to reach space. Sputnik transmitted at 20 and 40 MHz which are considered high frequency (HF) and very high frequency (VHF) radio and would have been detectable by many ham radio operators of that day. GSM and Wifi both operate at higher frequencies than this. Dragons flight (talk) 18:38, 16 February 2015 (UTC)[reply]

Much Thanks! Did Wi-Fi been using GPRS, or only GSM is been using GPRS? So, I thinking that only with GPRS is been full usefully using!--85.141.237.205 (talk) 20:31, 16 February 2015 (UTC)[reply]

Wi-Fi was designed for the transmission of packet data in the form of ethernet frames (really I think most would have expected it to be generally IP which had become the dominant ethernet protocol for most purposes by the time). It has no need for GPRS. Similarly LTE or really I think most or all proposals for 4G protocols are designed to provide an all IP entirely packet-switched network. (In other words, even voice calls will always be packet switched if over these networks, e.g. VoLTE.) Nil Einne (talk) 03:20, 17 February 2015 (UTC)[reply]

Thankful, By what was depended on the recoupment of the using (useful useless) of Wi-Fi or GSM? So, I thinking that program logical versions of TCP IP is been made a differences in full useful using (in useful useless) between Wi-Fi and GSM, but did it done the radio distance?--83.237.215.228 (talk) 10:54, 17 February 2015 (UTC)[reply]

In some countries GSM is billed very expensive while the try to etablish a billing system in WiFi by default failed due number and range of cells. WiFi transmits more data per time than GSM. EDGE, 3G (UMTS is here), followed by 4G (LTE) that just covered data volumes of older Wi-Fi, using IEEE 802.11 standards. --Hans Haase (有问题吗) 13:49, 17 February 2015 (UTC)[reply]

I understood so, that from transit of data is been responding the phone servers, but not doing this by the radio cells, is it being right?--85.141.239.56 (talk) 10:06, 18 February 2015 (UTC)[reply]

I’m understood so, that the radio cells did not transit of data without phone servers, is it being right? So, the logical radio cells did not existed (existing)!--83.237.244.20 (talk) 15:23, 18 February 2015 (UTC)[reply]

I’m believe that the phone servers are being manage (operate) the radio cells, but not phones (client devices) are doing that. So, the phone servers are always seen the all phones (client devices) which were being in the net. Is I’m right?--83.237.195.152 (talk) 19:18, 18 February 2015 (UTC)[reply]

So, all this makes me to thinking that cell telephony is being a simple local network.--85.141.234.3 (talk) 02:49, 19 February 2015 (UTC)[reply]

It is being well public known that the structure and architecture of simple local networks is always being determines by the servers.--83.237.209.57 (talk) 04:15, 19 February 2015 (UTC)[reply]

So this ways and that, the phone servers are always keeps counting of all network clients, but not the radio cells doing this, becouse it was being the simpel local network! Could the radio antenna been operate the radio network, I’m did know.--83.237.220.88 (talk) 05:10, 19 February 2015 (UTC)[reply]

Anyhow, all telephony is being a networks of different levels of logical (of different skills level).--83.237.212.29 (talk) 07:11, 19 February 2015 (UTC)[reply]

Drinking water vs. drinking water with sodium electrolytes[edit]

Since drinking "too much water" can cause hyponatremia, would it be safer to drink the same amount of water but with sodium electrolytes added? Will that still be enough to kill a human being, or will the electrolytes stave off death by keeping the body in isotonic equilibrium? How much is "too much" then, if electrolytes had been added? 66.213.29.17 (talk) 18:16, 16 February 2015 (UTC)[reply]

There is no type of water that can be consumed in infinite quantity (obviously), but adding some sodium will increase the amount that can be tolerated. Adding some potassium and a bit of glucose will increase it even more. The optimal result: Gatorade! (Approximately.) Looie496 (talk) 18:38, 16 February 2015 (UTC)[reply]

You still haven't discussed the mechanism that prevents consumption of massive quantities per unit time or what the limit is. So, my question still stands. 66.213.29.17 (talk) 19:08, 16 February 2015 (UTC)[reply]

The mechanism is basically that the body maintains differences in ionic concentration between the interior and exterior of cells -- high potassium inside, high sodium outside. Those concentration gradients are crucial for cellular function. If they break down, the cells in the body die. Our membrane potential article describes the mechanism in more detail. Looie496 (talk) 19:53, 16 February 2015 (UTC)[reply]

What if you drink large quantities of water+sodium+potassium per unit time? Can't ligand-gated and voltage-gated sodium and potassium channels just allow the ions to permeate through the membrane, creating an equilibrium? If it's possible to sustain equilibrium, then can you drink massive quantities? 66.213.29.17 (talk) 22:23, 16 February 2015 (UTC)[reply]

Well, if you managed to avoid any ion problems, the next problem would be the physical space the water takes up. That is, the stomach can only hold so much water, and the body can only process water into urine so quickly. For most people, trying to drink more water than their stomach can handle would result in vomiting. For those who lack a functioning regurgitation response, it might actually be possible to rupture the stomach and kill themselves in that manner. StuRat (talk) 22:31, 16 February 2015 (UTC)[reply]

No, with Gatorade you will lose to many nutrients to barfing! --Stephan Schulz (talk) 18:48, 16 February 2015 (UTC)[reply]

Actually the optimal result is more like Pedialyte, which is used for treatment of severe diarrhea, especially in children. Looie496 (talk) 19:01, 16 February 2015 (UTC)[reply]

BTW, you would normally get the electrolytes you need, to go along with your water, by eating food that contains them. It's only drinking lots of water without eating (or without eating much) that is likely to cause an electrolyte imbalance. In fact, the typical Western diet is so heavy in salt, that you aren't likely to suffer from any lack of sodium from drinking water. However, exercising in hot weather is a typical case where you drink lots of water (to replace the lost sweat), without eating, so do need to worry about the loss of electrolytes. StuRat (talk) 18:58, 16 February 2015 (UTC)[reply]

I've never had any problems with Gatorade. If Stephan does, he should consider talking to his doctor about it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:44, 16 February 2015 (UTC)[reply]

Four gallons of water will kill an adult drunk at one sitting. Adding electrolytes helps, but not much, since the body already compensates. The problem is that the water cannot be passed quickly enough. The idea of Pedialyte (a wonderful thing) is to replace the lost water as it is lost, not to prevent one from drinking it to the point of causing water toxicity. μηδείς (talk) 22:30, 16 February 2015 (UTC)[reply]

Medeis, what do you mean? "...kill an adult if drunk at one sitting...", or does water intoxication occur more easily in those already impaired by alcohol intoxication? Nyttend (talk) 04:37, 17 February 2015 (UTC)[reply]

Drunk is the adjectival past participle of drink. "Drunken" is a restrcted adjective meaning having drunk a toxicating amount of alcohol, which is not relevant here--at least in my dialect. E.g. the "drunken sailor" versus the amount of water that had been drunk. μηδείς (talk)

Okay. The only difficulty was the noun use of "drunk", e.g. "there's a drunk, lying in the gutter". Nyttend (talk) 04:52, 17 February 2015 (UTC)[reply]

Well, the point is to replace the lost water and electrolytes. StuRat (talk) 23:11, 16 February 2015 (UTC)[reply]

If one were able to maintain tonicity through constant imbibition, there's be no need for IV's and saline with glucose. I am tempted to say we should offer a reward to see who can drink the most hillbilly gatorade without dying, but that seems disethical, and a google search on the topic is not helpful. μηδείς (talk) 01:43, 17 February 2015 (UTC)[reply]

Well, most of us don't need IV's most of the time. That's only for when we can't drink normally, or when they are administering other meds. StuRat (talk) 03:05, 17 February 2015 (UTC)[reply]

Or when you've lost a lot of blood but not enough to warrant blood transfusion or have gotten dehydrated to the point where it's deemed a necessity. At least in Israeli hospitals. (Voice of experience, sadly) Sir William Matthew Flinders Petrie | ^{Say Shalom!} 28 Shevat 5775 05:15, 17 February 2015 (UTC)[reply]

Wouldn't those fall under the category of "when we can't drink normally" ? StuRat (talk) 16:39, 18 February 2015 (UTC)[reply]

How could a human stomach hold four gallons of water? Can it stretch that much? And keeping in mind the weight also, which would be like 32 pounds. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:57, 17 February 2015 (UTC)[reply]

You're not thinking this through. If it remained in the stomach, it wouldn't be a problem would it?! Water doesn't stay in the stomach for long - it heads through the intestines, where it's rapidly absorbed into the blood...and THAT's where the problem occurs. So stomach capacity doesn't enter into it. The only route for water to emerge as urine is via the blood, and through the kidneys - and that's where the problem occurs. SteveBaker (talk) 14:56, 17 February 2015 (UTC)[reply]

This is beyond easy. Just google "dies after drinking four gallons" which includes results with gatorade. μηδείς (talk)

That case was 2 gallons of water plus 2 gallons of gatorade - so it doesn't answer the question of whether gatorade alone would have helped...for that, you need my next response.

Gatorade and Pedialyte are not sufficiently balanced to prevent problems. Our article has a reference that proves the exact point [1] :

"Both before and during the game, Wilbanks drank Gatorade and Pedialyte, beverages with sodium concentrations that are higher than in water but lower than what is naturally found in the body".

...the problem being that there isn't sufficient electrolytes even in those supposedly balanced drinks to prevent problems. In this case, the kid's brain swelled up and caused his tragic death. My bet is that if you had a solution with sufficient salts and sugars in it to prevent the problem, it would be hard to keep it down without vomiting it back up again....but that's just a guess. SteveBaker (talk) 14:50, 17 February 2015 (UTC)[reply]