Wikipedia:Reference desk archive/Science/2006 June 12

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[edit] Headset adapter question

I'm interested in using an Altec 502i headset (designed for a computer, link here [1]) with my telephones. The product description on amazon says that I would need an "adapter", but it doesn't say what kind of adapter. What kind of adapter would I need? A link to an amazon.com item would be perfect. Thanks! -- Creidieki 01:32, 12 June 2006 (UTC)

It depends mostly on your telephones. Some mobile phones have 2.5mm jacks, which look just like the standard 3.5mm audio jacks, but obviously are a bit smaller. This would be all you need.

[edit] Seizures and blood pressure

tyring to find info on seizures related to sudden blood pressure increse or decrease [unsigned]

  • If we had more information, it might be at hypertensive encephalopathy or malignant hypertension, but I looked and there's not much there on seizures. They might be useful as search terms in Google, though. That's for seizures due to high blood pressure; for low blood pressure you might try ischemic encephalopathy. - Nunh-huh 12:48, 13 June 2006 (UTC)
Hypertensive encephalopathy is a redlink, as is ischemic encephalopathy. It appears we only have encephalopathy, which doesn't really answer the question. The sudden fall in blood pressure that accompanies a vasovagal syncope, is often accompanied by seizures. This is a normal reaction that can be triggered by anxiety. I've seen people who are afraid of the sight of blood, doing this when coming to have a blood sample taken, before venipuncture. It does not indicate any underlying brain pathology. --vibo56 talk 13:55, 17 June 2006 (UTC)

[edit] moon

wats the scientific reason behind the increasing n decreasing shades of moon???

Lunar cycle -- Миборовский 04:05, 12 June 2006 (UTC)and is a very interestin planet by jake

[edit] Insect question

Many insects like moths are attracted to light. This could present a major problem if moths develop to the point that they drive automobiles, as two moths driving in opposing directions would be drawn towards each other's headlights resulting in a head-on collision. What steps have been made to prevent this potential tragity? Mayor Westfall 04:16, 12 June 2006 (UTC)

Members of arthropoda were actually a highly-evolved, starfaring civilization that was unfortunately wiped out by a doomsday device they created when a hapless mechanic got too enamored by the blinking lights on it and pressed the start button. Unfortunately, the stop button was not illuminated. -- Миборовский 04:23, 12 June 2006 (UTC)
There is no problem. The moths will be attracted to the light, but the cars won't be, so the moths will leap out the window to their deaths, and the cars will float harmlessly into the ultra-rubber road barriers.  freshofftheufoΓΛĿЌ  05:47, 12 June 2006 (UTC)
Did you read our article on moth? They would only circle each other.--Shantavira 07:37, 12 June 2006 (UTC)
Wouldn't they crash into each other while trying to circle one another--that is if they are going in opposite directions, they're paths would curve into one another. Or would they...Now I have a math question that is bugging me because of this stupid question.
You may be confusing moths with black holes.  freshofftheufoΓΛĿЌ  04:50, 13 June 2006 (UTC)

Say you have two moths flying toward each other carrying a light source. They are attracted to light 10 meters away, and their paralell paths are seperated by 5 m, would they crash into each other? I suspect this would depend on their initial velocities....Sounds like this would make a good text book calculus question. Anyone have an answer? XM 12:21, 12 June 2006 (UTC)

Have you ever seen a moth fly? That's not calculus, that's turbulence. Black Carrot 21:40, 12 June 2006 (UTC)

[edit] Web

Can there be non www websites (those that dont start with www.)--are there any? And can there be anything for the suffix part of the address--instead of/ .com .org .net .edu .uk etc.... Mayor Westfall 04:43, 12 June 2006 (UTC)

To answer the first question: yes. You're on one. wikipedia doesn't require a www, and usually uses a language code. There is no restriction about this part of the URL. One website uses xxx instead of www, the physics arxiv. As for the second question, see top level domain for a list of what the final parts can be. -lethe talk + 04:55, 12 June 2006 (UTC)
For the first part (the www and things that replace it), see subdomain (and you can have sub-subdomains and such). Within the domain name, things go from largest on the right to smallest on the left. --AySz88\^-^ 06:21, 12 June 2006 (UTC)
There was a crazy Math teacher in my college whose website was wwww. ... .br people always wondered what that could mean. Everyone knew he was a Nazi (really) so people usually associated that, like White World Wide Web and stuff like that. VdSV9•♫ 11:48, 13 June 2006 (UTC)

[edit] Birds' sexual organs

When two birds mate/have sex/whatever, what part of the bird's anatomy is stimulated in order for it to have an orgasm? As far as I know, most birds have no obvious external sexual organs (I know that a few species of birds do have a penis but for the sake of argument, I'm talking about the majority that don't). As anyone that's ever owned a male budgerigar can tell you, birds (or at least budgies) do have orgasms and will dry-hump just about anything in order to get themselves off - I'm not 100% sure about hen birds but I presume they get something out of it too, otherwise there'd be no incentive to mate. Basically, what part of the bird's anatomy is analogous to the penis or clitoris? —The preceding unsigned comment was added by 81.77.227.52 (talk • contribs) 22:09, June 11, 2006 (UTC)

  • Our article on birds probably mentions cloacas. There's enough animals that don't get any pleasure out of sex. In those cases they're simply acting on their instinct to survive and produce offspring. - Mgm|(talk) 08:58, 12 June 2006 (UTC)

[edit] learning how to fix mobile phones

Hello All,Good Day.

I am hoping to learn the skill of fixing mobile phones. Which is both for hardware and software. I have access to buying all the necessary machines for doing this job, but I have no idea, how do I go about starting it, and how mobile phones work, and how to check, which part of the phone is not working, thus thereafter be able to fix it.

I did few searches on wiki, but nothing concrete showed up to guide me, so any help on how can I find such topics on wikipedia or any help on directing me to where I can find such specific help, will be highly appreciated.

Best regards,

Ken.

  • I'm sorry to say this, but if you have no ideas about the inner workings of a mobile phone, starting such a business on your own is probably a bad move. Try learning with a existing company first. (Also mobile phones differ in design between brands). HowStuffWorks.com should have a nice article on the subject of how phones work. - Mgm|(talk) 08:55, 12 June 2006 (UTC)

This would not be a good medium-term business. Phones are gravitating towards the 'unfixable', like a memory chip or processor. Either phones become a single chip you put in your ear, or they keep the same format and become computers. --Zeizmic 11:43, 12 June 2006 (UTC)

    • Your right there is little fixing possible at the PCB level with a board that fine but there are still many other things that can go wrong with a phone like gunk in the keypad and on contacts between various parts that can be fixed with simple dismantling cleaning and reassemblly, i have a feeling that this is a large part of what phone repair shops spend thier time doing. As for single chip in your ear unless voice recognition improves hugely i can't see people accepting it. Plugwash 11:55, 12 June 2006 (UTC)

[edit] Civilization of birds

Suppose that humans became totally extinct, leaving the planet intact (i.e. no nuclear war, asteroid strike or anything like that) and that birds eventually evolved, over several million years, to fill the niche left behind. Which species of bird do you think would be the one to step up and assume the role of 'masters of the planet'? Parrots? Crows (these seem to be the most intelligent birds)? Anyone have any theories? --81.77.227.52 06:33, 12 June 2006 (UTC)

I don't think it would be a matter of intelligence as much as of being omnivorous. As far as I know, crows eat pretty much anything and so do seagulls. –Mysid(t) 07:10, 12 June 2006 (UTC)
Seagulls are tough and adaptable but the parrot species have a complex social structure and have already evolved the opposable 'thumb' (toe, in this case). Surely the ability to manipulate objects with more than a beak alone would be an advantage? --81.77.227.52 07:15, 12 June 2006 (UTC)
Depends what you mean by "niche". The first bird to move into an empty house is always the pigeon, but they wouldn't be able to drive the buses. I would have thought mammals would be more likely to take over most of the opportunities. Some countries already have more sheep, cattle, or pigs than humans, so presumably the land would be left to them.--Shantavira 07:50, 12 June 2006 (UTC)
Cattle and other domestic animals have, however, been overbred to produce as much milk or meat as possible, so that they are unable to move or react as fast as required "in the wild". Many of them would be unable to survive without humans. –Mysid(t) 07:59, 12 June 2006 (UTC)
Who said that humans are the masters of the planet now? Us humans? Why aren't ants the masters? or beetles? or bacteria? ;-) —Bkell (talk) 08:48, 12 June 2006 (UTC)
Because bacteria have not formed cooperations that produce anti-humanic drugs, and ants & beatles don't spray chemicals on human cities to remove them from their habitat. XM 13:11, 12 June 2006 (UTC)
If you want to be anal about it, ants do spray chemicals to remove just about anything edible from the environment. They are just more ecofriendly than humans. Humans kill the ants and let them rot. Ants make a chemical trail to a food source (could be a human) and rip it apart into little bite-size chunks. However, I do not like this question. Why should birds take over? Why should it be a land animal? Why not the dolphins? A proper question would be: If humans were gone, would there be an animal that would spread across the entire world, pushing out other animals and plants? --Kainaw (talk) 13:30, 12 June 2006 (UTC)
I think it wouldn't be any kind of bird. It would be some kind of mollusc or insect, or crocodile. Dolphins would still be the most intelliegnt species (if they'd still be here) but of course they won't be the 'masters' but just continue to play joyfully as ever. – b_jonas 09:06, 12 June 2006 (UTC)

Seems like chimps would step it up, as they are closest to us XM 13:13, 12 June 2006 (UTC)

To replace humans something would need the ability to use tools, and need hands and opposable digits, so monkeys seem the only likely successor, possibly through evolution, leading to another humanoid race. Philc TECI 19:37, 12 June 2006 (UTC)
But one that would look as different from chimps as we do (more or less, most likely). However, whoever "rules the world" after us might not be a "civilization," as the header implies. Dinosaurs, for example, were the top predators for a long time, but had limited mental capacity. I can imagine the descendents of eagles, say, coming "on top" without building a civilization. zafiroblue05 | Talk 00:57, 13 June 2006 (UTC)
leaving aside the impossibility of assuming that any species of sub-species will achieve evolutionary success in the environment of the unknowable future I'd go with the 2 birds that can already be considered as tool users. That is the Raven which has been known to drop pebbles into water to raise the water level so it can drink; and the Indian Black kite which picks up burning branches & drops them somewhere a fire can start inorder to scare out prey. AllanHainey 11:29, 13 June 2006 (UTC)
Nah, you're all wrong. It'd be the rats. Skittle 12:58, 13 June 2006 (UTC)
Whenever it comes to defining a creature that rules the world, why is aquatic life always completely ignored, despite water covering 70% of the surface of the earth. Philc TECI 15:25, 13 June 2006 (UTC)
I think the reason is based on moving under water. Even the smartest water creatures must have a fin to move around. If they don't have fins, they'll grow them, like whales (or, to be precise, they'll evolve to have them). The necessity for fins more or less precludes the development of anything like opposable thumbs, so they'll never really develop an extensive use of tools, and therefore will never have civilizations. zafiroblue05 | Talk 21:39, 13 June 2006 (UTC)
...or discover fire for that matter. They also smell of fish. ;P --Kurt Shaped Box 21:59, 13 June 2006 (UTC)
Yeh but dinosaurs didn't exactly lay down the foundations of modern civilisation, and they're still considered to have ruled the world, if you ask me the aquatic life at the time of the dinosaurs ruled much more of the world than the dinosaurs. Philc TECI 23:19, 14 June 2006 (UTC)

[edit] dna

What's the difference between - INVERTED REPEAT & PALINDROMIC SEQUENCE ? —Preceding unsigned comment added by 59.93.201.69 (talk • contribs)

An inverted repeat is called a palindrome when no nucleotides intervene between the repeats. –Mysid(t) 07:09, 12 June 2006 (UTC)
For example,
GTACCAG-GCAAATC-GACCATG
is an (or has an) inverted repeat, while
GTACCAGGACCATG
is a palindrome (that is also an inverted repeat). zafiroblue05 | Talk 01:04, 13 June 2006 (UTC)

[edit] difference b/w velocity and acceleration?

what is the difference b/w velocity and acceleration?...please illustrate me with simple example. thanks —Preceding unsigned comment added by 80.247.152.121 (talk • contribs)

Velocity describes how fast an object moves (its speed) – acceleration describes the rate of change of its velocity. –Mysid(t) 07:05, 12 June 2006 (UTC)

actually i m having problem understanding the term "rate of change of velocity"...can u kindly explain it please???

It is how fast the speed changes. Let's say you're driving a sports car at 80 mph, and just for the fun of it accelerate to 90 mph. Let's also assume that it took, for example, 5 seconds to do that. Now your velocity has changed 10 mph in 5 seconds—this is the rate of change of your velocity. If the acceleration of same amount takes longer, the rate of change is smaller. The acceleration can be calculated by dividing the change of velocity by the time it takes; a = 10 mph / 5 s ≈ 2.93 ft/s². –Mysid(t) 08:10, 12 June 2006 (UTC)
You're driving along the road at a steady 60 kph (or 16.66 meters/second). Then you speed up for 20 seconds until you reach 70 kph, then maintain that speed. In those 20 seconds, your velocity (= speed) increased from 60 to 70, an increase of 10 kph. 10 kph over a period of 20 seconds works out to be an acceleration of 13.9 centimeters per second per second. JackofOz 08:15, 12 June 2006 (UTC)
As another example, if you're driving at a constant 100 km/h, then your velocity is 100 km/h, but your acceleration is zero, because your velocity isn't changing. If you decide to speed up, then as you speed up your acceleration will be positive and your velocity will increase; if you decide to slow down, then as you slow down your acceleration will be negative and your velocity will decrease. (As you slow down, your velocity will remain positive, as long as you're still moving forward, even though your acceleration is negative.) —Bkell (talk) 08:44, 12 June 2006 (UTC)
A change in direction is also a change in velocity, hence travelling at a constant speed in a cricle also has acceleration. Philc TECI 19:35, 12 June 2006 (UTC)
As a further example, you're driving along in your car at 200 km/h (55.5 meters per second), and you hit a brick wall, coming to a stop in ten milliseconds. Your acceleration is (55.5 m/s) / (0.01 s) = 5,550 meters per second per second, or about 555 times the force of gravity. Ouch. --Serie 22:06, 12 June 2006 (UTC)
Which neatly illustrates the fundamental difference. Velocity is a measure of one effect of a force, whereas acceleration is a measure of force itself. JackofOz 23:51, 12 June 2006 (UTC)

[edit] Body Volume

Can you please supply me with the average VOLUME of the human body? This can be answered in cubic inches or cubic centimeters, preferably the former. Many Thanks Dr. Robbie Brown.

Ask A Scientist discussed the same – it can be found out by dividing the average human mass by 0.001 kg/cm³. According to human weight, an average US male weighs about 80 kg, so the average volume of an US male would be 80,000 cm³. –Mysid(t) 07:36, 12 June 2006 (UTC)
  • You could find out your own volume for yourself (although it's a bit messy). Fill a paddling pool to the rim with water and carefully step in and subnmerge yourself entirely. When you're done, step out and measure the amount of water still in the pool. The amount of water that spilled over when you went under is your volume. I don't recommend using your bath tub for this. After you get that amount of liters or gallons, cubic centimeters or inches are only a calculation away. - Mgm|(talk) 08:51, 12 June 2006 (UTC)
Eureka! --Ginkgo100 talk · contribs 19:10, 12 June 2006 (UTC)
Just weigh yourself. For a first approximation, your density is about the same as water: about one gram per cubic centimetre. (You can shift that by five percent or so depending on whether or not your lungs are full of air, and whether you count that as part of your volume.) Note, for your convenience, that Google can do unit conversions for you—follow the link for an example: 1 cm^3 in cubic inches. TenOfAllTrades(talk) 16:44, 12 June 2006 (UTC)
The calculs are plain. Man floats a little (nose, chin and toes), so his density is not very different from water's, this is what Ask a Scientist's constant says. 1 kg of water defines a volume of 1 liter or 1 dm3. So man's volume is its weight in dm3, 1000 x his weight in cm3. For in^3, try Gogle and search, eg, "80000 cubic cm in cubic inches" which gives 4882. --DLL 16:44, 12 June 2006 (UTC)
A better approximation would be 1 kg body weight = 0.9L = 900ml. Non-average fat and muscle percentages change this. For a 70kg person, then 63L --Seejyb 22:44, 12 June 2006 (UTC)

[edit] additives

which kind of organic nitrates are added to diesel?


Cyclic nitrates are usually used as a diesel fuel additive.They reduce the autogenous ignition temperature of diesel fuel more than aliphatic nitrates; bicyclic nitrates are more effective than monocyclic nitrates, ex- cyclohexyl nitrate . Also, the organic nitrates proved to be the most suitable as components of starting fuels for diesel engines. (Ref: Springerlink)

[edit] pop and pop3

i've encounterd within my mobile a computer term pop3 server wat is this??? and what is pop??....also there are two other terms WAP and secure WAP Network...please inform me about these!...thanks

Try the articles Post Office Protocol and Wireless Application Protocol. —Zero Gravitas 07:51, 12 June 2006 (UTC)
(after edit conflict) Briefly, POP stands for Post Office Protocol, a communications protocol used in email services, and 3 is its current version. A POP3 server is an email server where your emails arrive and where you can download them to your mobile phone. WAP stands for Wireless Application Protocol, and it can be used e.g. to access Internet from the mobile phone. –Mysid(t) 07:54, 12 June 2006 (UTC)

[edit] mobile phone as modem!

i've a smartphone "i-mate sp3i"...and i want it to serve as modem for my PC. i tried to search for it on i-mate's official website but couldn't find any material...

actually i use gprs on my phone n browse websites but i want to browse these websites on my pc through mobile.i ensure you that my mobile has this option to act as modem for my PC..but i m unable to find that option..please help me????

[edit] IP address configuration

Hi, I need to configure my laptop as the DHCP client in the office but assign a static IP at home, for the broadband connection. As of now, I do this change manually every day. Is there a utility which will allow me to reconfigure these settings on the fly ? -- Wikicheng 09:04, 12 June 2006 (UTC) '

  • Additional information please; What operating system are you using? -Benbread 10:57, 12 June 2006 (UTC)

It is Windows 2000 professional. -- Wikicheng 12:04, 12 June 2006 (UTC)

The manual way to change it would be to look into the properties of the network interface, then look at the properties of "TCP/IP settings" and changing it there. But there must be an API for easily changing these settings. I know it. -- Daverocks (talk) 13:50, 12 June 2006 (UTC)
I haven't tried it myself, but a bit of googling (the first hit for windows dhcp static bat if you must know) finds this. Create .bat files with those one-liner commands, make shortcuts for both to the desktop and Bob's your uncle (knock on wood). (notmyfaultifyoufryyourcomputer.) Weregerbil 19:22, 12 June 2006 (UTC)

PERFECT !!! It works!. Just what I was looking for. Thanks a lot. -- Wikicheng 04:06, 13 June 2006 (UTC)

[edit] Several Science Experiment Questions

For a home science assignment I am doing an experiment on the effects of age on cognitive ability and memory. How I am doing this is getting some cards with 10 numbers, 10 letters and 10 mathematical questions on it. I get the subject to remember the numbers and letters for a set amount of time and after 5, 10 etc minutes I ask them to recall. I then record their success rate. I then ask them to complete the mathematical problems which I time. These two values I compare to other people from different ages etc.

In this type of experiment, what is the control? would it be the average of all scores?

Any improvements I could make to it?

Also, the assignment calls for a "background" section to be written as well as the Aim, Method, Results, Conclusion etc. In a formal experiment, what is the "background"?

Thanks Wayne

You would not really have a "control", I don't think, although if you need one I suppose the average value of each age group would do (although this is certainly not a control in the strict sense). You could mention things like the standard deviation at each age group (which, I would imagine, would vary considerably as you get to the youngest and oldest members of the experiment). Your test sounds fine, but it does sound a little easy. I would imagine that most people can remember 10 letters in a row in 10 minutes. Maybe you could try lowering the time a little, to increase the spread of results? Batmanand | Talk 11:26, 12 June 2006 (UTC)
They're not asking them to look at them for 10 minutes but to recall them after 10 minutes has passed. So increasing the time would make it harder, not lowering the time. Skittle 12:50, 12 June 2006 (UTC)
They get the numbers and letters to remember and they only get to memorize it for 2/3 minutes. Then I test them after 5, 10 minutes and mabye 20 or 30 minutes. Wayne
Most studies on age and memory have to do with transfer of short-term memory to long-term memory. That takes at least 20 minutes until an event is completely removed from short-term memory and in long-term memory. So, you should work on testing both. After 5 or 10 minutes, you are certain that the events (the cards) are in short-term memory and not long-term memory. 20-30 minutes later, it is in long-term memory. Obviously, mistakes they make in short-term memory will continue into long-term memory (unless they make a lucky guess). Your hypothesis can be that older people have a greater loss in transfer from short to long-term than younger people. You can even expand to include children. Are children better or worse than young adults? --Kainaw (talk) 13:23, 12 June 2006 (UTC)
I'm not sure that claim is completely accurate. The popular phrases "short-term memory" and "long-term memory" don't map directly onto the brain. When a subject is given a stimulus (e.g. a number on a card in this case) they will usually rehearse it by mentally repeating it. At this stage it is in working memory (or the phonological loop in Baddeley's terms). As long as the subject continues to rehearse it, for whatever amount of time, it will continue to be in working memory. It is for this reason that memory experiments often include a distractor task (e.g. simple arithmetic) between item presentation and test of memory retrieval. At the same time, the subject will be primed such that the stimulus will be more likely to be remembered given a cue or presentation of part of the stimulus (e.g. if the stimulus is a 9 digit number, given the first 5 digits). This is also a form of "short-term memory". Further, the details of the episode in which the stimulus was presented, as well as the stimulus itself, will be stored in the subject's hippocampus (part of "long-term memory") and will also leave a trace in other medial temporal lobe structures ("intermediate-term memory"). After a period of days, the content of the particular episode will slowly be consolidated into various association cortices (also considered "long-term memory"). The summary of the story is that a large number of different brain regions are all taking in the same stimulus and handling it in different ways, which do not all easily map onto a simple short/long-term distinction. Whew! That's a fair, quick summary... 128.197.81.181 18:28, 12 June 2006 (UTC)
I defentantly like the idea of testing the performance of the short term versus the long term memory of different people. I have changed it so they will be tested after 5/10 minutes and 30/40 minutes, however I will not restest the maths problems as that is not a memory test. I was also thinking of noting if a subject says that he or she says that they "cannot remember" or he or she gives incorrect results as I may be able to draw some (dunno what though) conclusions from this. - Wayne
I belive that the best way to compare the results would be by using a t-test. You can read about the t-test here, and there's a pretty simple on-line calculator here. You don't need a control group, by the way, since you yourself are not manipulating any variable. Rather you are comparing two populations to see if there is a significant difference between them. — Asbestos | Talk (RFC) 14:58, 12 June 2006 (UTC)
To answer the other part of your question: "Background" would be a description of what people generally write about memory, and how it changes with age. How long have people known it to happen? When do they say it should happen? Why does it happen? Quote a biology or physiology book. It would also include the difficulties that the changes you are measuring may be causing people, or the practical importance of the effect.. Background gives the reader a perspective on what you are testing, and why. --Seejyb 22:12, 12 June 2006 (UTC)

[edit] phd or research in Bioinformatics

I complited my M.Sc Bioinformatics from Tamilnadu and would like to do Phd or research in Bioinformatics from Bangalore or from Tamilnadu. I want to know which all universities are providing the Phd or research cources and how to apply for the same. What all qualities and qualification is needed?

Contact the universities in the geographical area where you would like to study and ask about their programs. --Ginkgo100 talk · contribs 19:13, 12 June 2006 (UTC)

[edit] Duchenne's muscular dystrophy

Concerned about the possibility of Duchenne's Muscular Dystrophy (MD) to future children by using the pedigree diagram and all other possibilities.

Scenario:

There is no evidence of MD on the husband's side of the family. The husband, the brother and the parents are normal.

The wife does not suffer from MD, and neither do her parents, but she has a brother who died from MD at the age of 7.

The couple have no children, but are anxious to start a family.

Please could anybody helps me with this.


Screen the mother for the mutation using haplotyping. If the mother is a carrier then there is a 50% chance of boys being affected and girls being carriers. Prenatal screening will allow potential fetuses to be tested for the mutation and aborted accordingly. --Username132 (talk) 14:35, 12 June 2006 (UTC)
See a genetic counselor to discuss the possibility. Rmhermen 14:59, 12 June 2006 (UTC)
Yep. Genetic counselor should be the one to help with all your information and decision-making needs. There are various associations in the UK, the USA (although this site looks more sentimental) and Australia, among others, that you may find helpful. There are associations in Canada and New Zealand and other countries too. They should be able to give you information and/or direct you to a specialist genetic counselor. Good luck with whatever decision you make. Skittle 16:17, 12 June 2006 (UTC)


[edit] Balancing a chemical reaction =

Hello, I need to find the product of this reaction and balance it.

(I used _ to denote a subscript. H_2 = H(subscript)2 )

H_2CrO_4 + AgNO_3 → _____

This is a homework problem, but I would just like a little help, could someone point me in the right direction? I do not have a problem balancing these, but every problem like this in my textbook already has the product written and I cannot find how to actually find the product of these type of reactions if it is not given. Dont I need to know the charge of those compounds? I guess the problem is, I can find the product of reactions composed of individual atoms, or cations/anions that I know the charge of (like Nitrate, Phosphate etc.. which are in my book), but I do not know the charge of the compounds in this reacion. And would AgNO_3 be called Silver Nitrate?

Also, if anyone has any helpful tips about these types of problems, please share.

Any help would be much appreciated!

--207.4.165.39 14:29, 12 June 2006 (UTC)

Where no charge is indicated, the charge is assumed to be zero (neutral). So H2CrO4 (chromic acid) has an overall charge of zero, as does silver nitrate.
The type of reaction here is called a double displacement reaction (also called a 'double replacement' reaction). When you dissolve those compounds in water, they break up into their component ions, and then figure out which anions can be paired off with which cations. You have to look for ions (anions/cations) that you recognize; you've probably got a list of common ones that you'll need to know. Hopefully that will get you started on your homework. TenOfAllTrades(talk) 14:51, 12 June 2006 (UTC)
I think the simplest thing to say is that you need to learn the charges of more ions. For this example, you have 2 H's in the first compound so you can figure out the charge on CrO_4 from that. For the second compound you should learn the NO_3 ion's charge (Ag also has a most common charge that is helpful to learn.) Rmhermen 14:55, 12 June 2006 (UTC)
More to the point, once you remember that HNO3 is neutral, figuring out the charge of the NO3 ion is easy. Of course, it's harder with polyprotic acids, such as H2CO3 or H2SO4 since those may lose a variable number of hydrogens to give ions with different charges. —Ilmari Karonen (talk) 16:03, 12 June 2006 (UTC)
  • But if H2CO3 or H2SO4 lose all their hydrogen ions, the charge of the remainder ions is still simple to figure out. - Mgm|(talk) 08:11, 13 June 2006 (UTC)

[edit] Using a second screen just to show a screensaver

Large "digital frames" that you can hang on your wall to display your digital pictures are much more expensive than regular lcd computer monitors. Is there any way, using windows, that I could attach a second screen to my computer, hang it on the wall, and set it to show my photo-viewing screensaver? Any thoughts or advice? — Asbestos | Talk (RFC) 16:58, 12 June 2006 (UTC)

That's feasible, but may be tricky to achieve. Another idea is to get a LCD TV, and use your digital camera. Most of them come with a form of video output, and support slideshows. This would involve the least amount of wiring and fuss with your PC. Also, LCD TVs are generally cheaper than LCD computer screens.
A second monitor is not difficult. You just need two video-outs. Dual-head cards make it very easy. As for the program, there are photo-viewing programs (doesn't Windows XP come with one built-in?). If you really like the screensaver version, you can run screensavers as programs. You don't have to lockup the computer. The problem you will have is that the mouse will tend to get lost when you accidentally drag to the second monitor. --Kainaw (talk) 17:45, 12 June 2006 (UTC)
Ok. Would there be any way to lock my mouse into my primary monitor when I'm not changing anything in the second monitor? — Asbestos | Talk (RFC) 17:55, 12 June 2006 (UTC)
Not that I know of. It would, of course, depend on the video driver. All of the popular ones that I've used allow the mouse (and windows) to slide back and forth freely between the monitors. --Kainaw (talk) 18:00, 12 June 2006 (UTC)
There exist mouse utilities that allow you to set boundries for the pointer. I could never reason why they would want to do that but it seems it would be useful in a situation like this.  freshofftheufoΓΛĿЌ  02:23, 13 June 2006 (UTC)
I've never used this program but it seems to be a pretty universally respected piece of code: Ultraman has a setting to Lock mouse to active window or primary monitor.  freshofftheufoΓΛĿЌ  02:34, 13 June 2006 (UTC)
Thanks! 65.96.107.116 12:34, 13 June 2006 (UTC)

[edit] training as bodybuilder

what role does taking or knowing about atp plays in my quest as a natural body builder

Are you referring to adenosine triphosphate? --Kainaw (talk) 18:02, 12 June 2006 (UTC)
I've never heard of anyone taking ATP as a supplement, if that's what you're asking. Your body makes more than enough ATP for its own purposes (the article in fact states "1 kilogram of ATP is created, processed and then recycled in the body."). As for knowing about ATP? I can't really see how knowing about ATP will affect your body building much — do you need to know how the CPU works to be able to use a computer? — but learning about ATP will probably play a part in your quest to understand high-school biology. — Asbestos | Talk (RFC) 18:21, 12 June 2006 (UTC)
Yuck. I take back what I said above: it looks like there are a lot of people selling "ATP supplements" over the web, some even claiming that all but the puniest of "weekend warriors" really need their products to prevent strokes and what-not. In my view this is BS and they are selling snake-oil. The only piece of supporting evidence I could find skimming through Google Scholar was an article saying that it may help prevent brain damage after trumatic head injuries in rats. Unless you plan on getting hit in the head a lot, and are a rat, I personally don't see the point. — Asbestos | Talk (RFC) 18:31, 12 June 2006 (UTC)

It might make you more energetic. Yanwen 19:10, 12 June 2006 (UTC)

How? ATP is a cell's "energy currency," but all the ADP/ATP a cell needs is already present. The body is designed to derive its energy ultimately from carbohydrates, fats, and proteins, and it is stored in those forms as well. --Ginkgo100 talk · contribs 19:17, 12 June 2006 (UTC)

[edit] Genetics

Actually I'm brunet with a bit dark skin. If I marry a tall blue-eyed blonde, what is the probability of the nordic type person birth (any gender)? I read it's small because my type is in fact a dominant gene. And how many generations should pass (counting my offspring as first) to achieve the nordic type? Thanks :) --Brand спойт 21:00, 12 June 2006 (UTC)

Hair_colour#Genetics, Eye_color#Genetics, and Skin_color#Genetic_determinants should help. Whether your kids display recessive characteristics, like blue eyes, depends on whether you're a carrier for that characteristic or not. Does anyone in your family have blue eyes? The "how many generations" question depends on who your children decide to breed with, and could only be answered with an estimate of probability. Black Carrot 21:33, 12 June 2006 (UTC)
No, nobody is blue-eyed in my family. What if I assume that my children will breed with the same-type partner? --Brand спойт 21:48, 12 June 2006 (UTC)
Assuming the trait is passed on through the simple dominant/recessive-type gene, a Punnett square will help you work out the probabilities from any breeding system you care to describe. I don't know how to work out anything more complicated than that. Black Carrot 22:20, 12 June 2006 (UTC)
Neither eye color nor hair color are single-gene traits, nor is being a "nordic type person". And all of the various genes so far identified as being involved are assorted independently. There's no way to make any reasonable prediction here. If you want to play around with what's understood, search Online Mendelian Inheritance in Man (OMIM) for "hair color" or "eye color". It will give you some appreciation of how much more complicated the transmission of these supposedly simply traits is than most people seem to believe. - Nunh-huh 22:45, 12 June 2006 (UTC)

Black is beautiful. Don't let the Nazis win. :D -- Миборовский 23:13, 12 June 2006 (UTC)

If you have double dominant genes, which is likely if you have absoultely no family history of these traits, all of you children will inherit the dominant traits, and none have the recessive traits. Philc TECI 00:04, 13 June 2006 (UTC)
Wrong. These are not traits transmitted at a single gene locus. It makes no sense to discuss them in terms of dominant vs recessive when the actual specific genetics have not been characterized. - Nunh-huh 00:34, 13 June 2006 (UTC)
Nunh-huh is correct, we simply do not know enough about the genetics of hair, skin and eye colour to accurately predict such things. The genes we do know of can give you some pointers, but unless you sequence your alleles, its very difficult to even speculate about these. Some recessive MC1R alleles predispose to fair skin, red/auburn/strawberry blonde hair and freckles. And SLC24A5 variation appears to corrolate with skin colour. There are also some recessive subclinical alleles of albinism genes (eg. Tyrosinase, Dopachrome Tautomerase and Tyrosinase related protein) that result in very pale skin and white/blonde hair. Oddly enough, the genetics behind Californian blondes (i.e. blonde hair, tanned skin) is currently unknown. It appears that it might have something to do with the structure of eumelanin biopolymers and is possibly dominant over red hair alleles.
So while it is not possible to accurately predict in any scientific way, what we do know would suggest the odds are against you producing "very Nordic" progeny. Since the paler phenotypes are often recessive (due to a loss of function in genes involved in melanogenesis) unless you are carrying recessive "Nordic genes" (which also appears unlikely), its probable your children will get an assortment of darker and lighter skin/hair genes. Exactly what that assortment means in terms of their manifest hair, skin and eye colour, well, thats anyone's guess. But its more likely to be something in between than at either extreme. Rockpocket 01:49, 13 June 2006 (UTC)
Actually, I believe that mixed-race babies tend to have fair hair and colorful eyes. So you can get your little halfbreed Aryan. But just for a few years. -- Миборовский 02:09, 13 June 2006 (UTC)
Charming. Genetic counseling from someone who finds "mixed-race babies", "half-breed", and "Aryan" to be useful categories. And is apparently unashamed! - Nunh-huh 04:44, 13 June 2006 (UTC)
I would have thought the ironic tone in Миборовский's post to be fairly obvious, but I guess not. — Asbestos | Talk (RFC) 15:46, 13 June 2006 (UTC)

Is it just me, or is this particular thread deeply disturbing? --Ginkgo100 talk · contribs 14:32, 13 June 2006 (UTC)

I'd say you're both deeply disturbing. *Cymbal crash* Black Carrot 22:37, 13 June 2006 (UTC)

[edit] The Genesis of Life- Crocodiles

Hello. My name is Natasha and I am really in a bind. I really need help finding information on the genesis of life for crocodiles. It is a school project, and tommorow is the absolute last day to work on it. I did need websites bacause that is what everyone is giving me. If you find anything on Spermatogenesis, Oogenesis, Female Ovulation, Fertiliation, Embryonic Development, Birth, and Genetic Variation, please just copy and paste and send it to me. Thank-you so much.

Troubled grade 9

You need to do your own homework. Nobody here will do it for you. Also, cutting and pasting is not what your teacher is looking for. (And not the point of your education.) The point is for you to learn something about the subject and demonstrate that to the teacher. I'd recommend that you actually read the articles on the topics you listed, and then write the paper based on what you have learned from them. Fortunately, you have a whole 2 days. --Booch 22:47, 12 June 2006 (UTC)
Hmm. Sorry about your bad planning! Our crocodile article doesn't help. Try searching google for "crocodile reproduction". There are some sites that you'll find that will be of use. [2], [3], etc. Similarly, "crocodile mating" and "crocodile fertilization" will all return useful results. - Nunh-huh 22:53, 12 June 2006 (UTC)
Doesn't a human fetus aged less than 2 months look like a crocodile's ? The we evolve and/or regress but they become perfect crocos for Mr and Ms Vuitton. --DLL 19:16, 13 June 2006 (UTC)

[edit] GMA 950

So the school I'm going to is reccomending that I get a Toshiba M400, they have some sort of special deal they're trying to negotiate.

The processors go anywhere from Intel Core Solo 1.6 to Intel Core Duo 2.16, not sure what they'll negotiate.

Memory will definately be 1 GB.

Gfx Card is unfortunately an Intel GMA 950 with 8 MB to 128 MB shared memory.

(12.1" screen = eww, Tablet = cool)

Now here's my question: Will I be essentially screwed as far as all gaming goes? I'm really hoping not, cause I was hoping for a laptop for the next few years that I wouldn't want to throw off a cliff. Also, anyone have this computer? How's it work

Looks like I'm going to be stuck playing the games on my desktop whenever I get a chance to get home. Oh well, less Hard Drive space hogs I suppose. Also, I wanted to get Oblivion but it looks like it'd run on my ATI Radeon 9600 better.

Maybe I should just badger my parents into getting a MBP 2.16 Ghz for me (Looks to me that unless the school gets a spectacular deal, the Toshibas will only be ~$500 less than the MBP, which has specs at about twice the Toshiba, especially graphics card). — Ilyanep (Talk) 22:53, 12 June 2006 (UTC)

It really depends what you mean by "gaming". Back when I played counter-strike, I considered a computer worthless if it couldn't run the game consistantly at 100fps+ without memory skips at 1024x768, or didn't have enough memory to smoothly concede minimizing the game client and loading third party programs.
Though CS is ancient, most current laptops still can't do that, but I'm guessing you won't be that hardcore for framerate. If you're into really pretty current FPSs or other depth-intense 3D games, then you'll probably be disappointed. I'm not sure how much better "sharing memory" methods are nowadays, but your vid card (and, of course, your screen) is really next to worthless as far as 3D gaming goes. On the other hand, RAM is sufficient and (if you get the 2ghz) there's probably loads of good games out there that you could run smoothly, as long as you manage your hard disk carefully to keep the cache file "cashing" smoothly.
Still, this computer is for school so you'd probably be better off using your laptop more productively... lets pretend the inadequacies are intended as a blessing to help you concentrate on your studies : ).  freshofftheufoΓΛĿЌ  02:15, 13 June 2006 (UTC)
Oh pshaw, I've got to live at this place :D.
Thanks for the help. Hopefully if the tablet isn't required we can go with a laptop at the same cost that has an ATI Mobility Radeon X1600. — Ilyanep (Talk) 02:51, 13 June 2006 (UTC)
They have begun issuing these to people I work with. What I don't get is, what's so special about the tablet feature? There is no way you can scribble half as fast or as accurately as you can type. I could see it making field work easier, since its a good way to navigate GUIs while being held in your hands. I don't see a single practical benefit to it for typical desk use, though. If you want to play Oblivion well, plan on spending a LOT for a laptop. And BTW, the reason no laptop can run CS at 100FPS is because no laptop has been made with a screen that refreshes that fast. Maybe because theres no perceivable benefit?
Agreed. But the MBP looks like it can run Oblivion at at least medium if not high settings. I think the Tablets are overpriced for a school setting. — Ilyanep (Talk) 16:55, 13 June 2006 (UTC)
Don't forget to factor in the cost of the windows XP license (wink) in the total cost of that system, since O won't run on OS X as far as i know. Also, put priority on the 256mb vid ram, and 2GB of sys ram, I play O a lot and it ran like crap without those.
Oh well, I'll probably uninstall XP on the computer I'm working on right now and put linux on it [to make it a file server] and then use this copy of XP on that one. Then I can keep Win and OS X backups on here and it'll basically be a free file server. — Ilyanep (Talk) 18:43, 13 June 2006 (UTC)

[edit] Odd Trait

What I was wondering was if talking during a T.V. show, or giving away the story is a recessive trait, because both my father's parents do so, thusly my dad and his sister also talk during shows. My mom doesn't and I don't, so would that make it recessive? schyler 23:56, 12 June 2006 (UTC)

I think that reasoning and manner of thinking and choice, are all factors and none could be attributed to a single gene. It is mostly choice really, unless they have OCD. Philc TECI 00:00, 13 June 2006 (UTC)
That sounds more like evidence of nurture than nature. Black Carrot 02:03, 13 June 2006 (UTC)
Strong anecdotal evidence suggests that the need to control the remote control is inherited together with the Y-chromosome. - Nunh-huh 03:38, 13 June 2006 (UTC)

But even if that particular trait isn't inherited, that is how a recessive trait works, right? schyler 12:44, 13 June 2006 (UTC)

A recessive genetic trait is passed on through a gene sequence on one half of a chromosome. If it is combined with a "dominant" sequence on the other, its instructions are effectively ignored in favor of those of its dominant partner. (I'd appreciate correction if I got the wording wrong.) Point is, that trait isn't recessive any more than a brunette is a tabby. However, were it being caused by an interaction of dominant and recessive genes, yes, that's what it could look like. Black Carrot 17:45, 13 June 2006 (UTC)
Well, not one half of a chromosome, but one half of a chromosome pair, or one of a pair of chromosomes. And most geneticists would use "allele" rather than sequence. It's also not that recessive genes are ignored: they are usually transcribed and produce proteins, but the protein produced by the dominant allele has an effect that negates that of the recessive allele's protein. (For example, women who carry one allele for hemophilia (which is transcribed to produce a defective clotting factor VIII) and one allele for normal factor VIII produce both defective and normal proteins, and the normal protein is present in sufficient quantity that they do not usually experience clotting difficulties.) - Nunh-huh 22:17, 13 June 2006 (UTC)
A situation known as haplo-sufficiency (though that article could do with some work). When the normal protein cannot make up for the deficit in function from the other allele, it is known as a haploinsufficiency. Rockpocket 02:22, 15 June 2006 (UTC)