Wikipedia:Reference desk/Archives/Science/2011 November 8

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November 8

Neurons v computer chips

Hi, The binary funtion has two states, on and off. How many states does the neuron have particularly the human one?

If you don't understand the question, the computer runs on wires which can be on or off, two states. The neuron works on chemicals and has more than simply on or off? ~ R.T.G 11:35, 8 November 2011 (UTC)

Neuron#All-or-none principle implies that there are only two states, firing or not, although the frequency may vary. (However I am not a medical person - I just had a quick look at the article.) Mitch Ames (talk) 12:08, 8 November 2011 (UTC)

But a neuron can't remain in a "firing" state, unlike a binary electrical signal, which can stay in either the "0" state or the "1" state indefinitely. A neuron also acts asynchronously, which is different from the synchronous circuitry within a clock-driven CPU. So the information content of a neuron's firings is roughly comparable to the information content of the timing of the leading edges of pulses in an asynchronous binary electrical signal. Red Act (talk) 14:48, 8 November 2011 (UTC)

Artificial neural networks, by the way, don't in general model a "neural" signal with an asynchronous one-binary-digit signal as mentioned above, but rather usually as a continuous-valued (actually multiple binary digit) signal, that's conceptually updated in discrete steps, synchronously with the other "neurons" (although the "neurons" are actually updated sequentially, unless perhaps if the ANN is being run on a highly parallel CPU). The idea is that the continuous-valued signal is analogous to the frequency with which a biological neuron fires. Red Act (talk) 15:27, 8 November 2011 (UTC)

Neurons are not binary. The internal state of a neuron can be extremely complicated. The mechanism by which neurons send signals to each other is simpler, though: most neurons signal using action potentials, and to a first approximation all action potentials have the same size and shape -- the only thing that distinguishes them is the time at which they occur. Thus the signals coming from a neuron can be thought of as a train of identical pulses, each of which can occur at an arbitrary time. (This is the common situation, but some types of neurons work differently.) Looie496 (talk) 16:01, 8 November 2011 (UTC)

You may be interested in quantum computing, which uses qubits instead of traditional 0s and 1s. ~AH1 ^(discuss!) 03:18, 9 November 2011 (UTC)

Or why not go to old circuits instead of future ones. In the past (before common computers) analog and digital circuits were often mixed together. The result was "digital" logic that used continuous analog voltage values. So, a "bit" could be anything from -5 to +5 volts. If you wanted an analog value, you just read it. If you needed a binary value, you use a transistor to fire off a positive value when the bit contained a value above a predetermined level. I know that is being very vague, but it is a lot more complicated than such a trivial example. -- kainaw™ 03:27, 9 November 2011 (UTC)

Binary can be on or off, 1 or 0 nothing else. Neuron can be on off and some other stuff, whatever that is. ~ R.T.G 18:08, 10 November 2011 (UTC)

A neuron can only be "on" or "off". A simple model is that a neuron has a bunch of inputs, and when the total input exceeds a certain level, the neuron flicks on then off again. The intensity of a signal is expressed in how often the neuron sends out a pulse. You can imagine that since all of the inputs follow the same rules, a greater number of inputs sending pulses with a higher frequency means that there are more likely to be beats (when multiple inputs pulse at the same time.) A beat is likely to exceed the activation potential, resulting in the neuron sending out a pulse. So, as the total input pulse frequency increases, so does the output, and the relationship between the two depends on the activation potential of the neuron. In this way, analog data is represented in the frequency of a digital pulse. As far as I know, the more the activation potential is crossed, the lower it becomes. This is what people are referring to when they talk about "pathways in the brain strengthening" etc. Teshmanesh (talk) 12:51, 11 November 2011 (UTC)

Oxidation & Reduction

3 Cu + 8 HNO3 → 3 Cu(NO3)2 + 2 NO + 4 H2O

(3 Cu + 8 H+ + 2NO3 → 3 Cu2+ + 2 NO + 4 H2O)

In the reaction above, how many moles of HNO3 would be needed to oxidize 3 moles of Cu? If it had asked "how many moles of "NO3-"?", I am certain that the answer would be 2 moles. But if it asks "how many moles of "HNO3"?" would the answer be 8 or 2?Johnnyboi7 (talk) 14:43, 8 November 2011 (UTC)

The answer would be 8. Since it takes 8 H+ ions to complete the process, you would need all 8 of "HNO3", even though you only need 2 of the NO3-. Look at it this way: Lets say nuts and bolts are packaged together in pairs, one nut and one bolt per package. Lets say you need 8 bolts and only 2 nuts to complete a project. You still need to open 8 packages, even if you only need 2 of the nuts. How you phrase the question matters. If you say "How many nuts do I need to complete 3 projects" then you need 6 nuts. If you say "How many packages do I need to open to complete the project", you need to open 24 packages, because even though you only need 6 nuts, you still have to open 24 boxes to get all 24 of the bolts. Same story here: If the question asks "How much HNO3 is needed to make 3 moles of Cu2+" then you need 8 moles of HNO3. If the question asks "How much NO3- do I need to make 3 moles of Cu2+", then you need 2 moles of NO3-. --Jayron32 18:50, 8 November 2011 (UTC)

3(Cu → Cu²⁺ + 2e^-)

2(NHO₃ + 3H⁺ + 3e^- → NO + 2H₂O)

3Cu + 2NHO₃ + 6H⁺ → 3Cu²⁺ + 2NO + 4H₂O

Here, two acid molecules are oxidising and six are acidifying, thus eight are neccesary to complete the reaction. Plasmic Physics (talk) 21:05, 8 November 2011 (UTC)

When writing redox half equations, it is good practice to never treat hydrogen as a spectator ion, this avoids the kind of problems that you just encountered. From the combined redox equation I gave, you can tell that two moles of nitric acid is required to oxidise three moles of copper, and six are used to acidifiy the reaction, and provide the correct counter ions to produce copper(2+) nitrate. Plasmic Physics (talk) 10:36, 10 November 2011 (UTC)

Signal Format Specification of Very Early Television Sets

From History_of_television#Television_sets,

"The first commercially made electronic television sets with cathode ray tubes were manufactured by Telefunken in Germany in 1934, followed by other makers in France (1936), Britain (1936), and America (1938). The cheapest of the pre-World War II factory-made American sets, a 1938 image-only model with a 3-inch (8 cm) screen, cost US$125, the equivalent of US$1,863 in 2007. The most expensive model with a 12-inch (30 cm) screen was $445 ($6,633)."

What was the signal format of the 1938 image-only models sold in America in 1938? Presumably, if they were going for US$125 in 1938, which the article says is $1,863 in 2007 dollars, somebody must have been making broadcast content that consumers wanted to see in that format. Is a link to that format specification to be had here in 2011? The format specification is all I want. 20.137.18.53 (talk) 14:54, 8 November 2011 (UTC)

We have an article on television systems before 1940 that details the many various standards that existed in the early era, and it appears that RCA's 441-line television system was the chief predecessor to NTSC. — Lomn 15:12, 8 November 2011 (UTC)

In case anyone wants to use the references: Grandiose (me, talk, contribs) 16:49, 8 November 2011 (UTC)

Properties of brass

what are the properties of brss?

Have you read our article on brass? — Lomn 15:57, 8 November 2011 (UTC) note: added title

Is the universe hologram-like?

How credible is the idea championed by Brain Greene? [1] Thanks. 65.88.88.75 (talk) 16:17, 8 November 2011 (UTC)

It's a real possibility that cannot be discounted off hand. So, yes it is credible. We don't know yet whether it's true or not. Dauto (talk) 16:32, 8 November 2011 (UTC)

By the way, I think the holographic principle was first proposed by Gerard 't Hooft and Leonard Susskind. Dauto (talk) 16:37, 8 November 2011 (UTC)

But, the holographic principle is just a special case of Green's theorem, which is some 2 or 3 centuries old. Green's theorem (or, more generally, Stokes' theorem) states that, for certain properties, it is mathematically equivalent to express as a volumetric vector field or as a surface potential. With sufficient extension, Green's theorem applies to arbitrary dimensional spaces and fields. For example, Gauss's law states that if we know the electric field at every point on a surface, we know the net charge inside the volume. By extension, if we can parameterize several vector-fields on a surface, we can compute the equivalent volumetric contents for anything that is physically related to those vector fields.

At present, we do not know a physical law that relates "everything interesting" to "some vector field," so even if the principle is theoretically valid, we aren't able to use it to effectively describe the arbitrary contents of a gaussian pillbox. (We do have several such laws, though: we can relate charge to electric field; we can relate mass to gravitational potential; we can relate mass flux to many properties, and so on). Nimur (talk) 17:07, 8 November 2011 (UTC)

That's not what the holographic principle is about. The holographic principle comes about because the maximum amount of information that can fit within a given region of space is proportional to the surface area of the region - not it's volume. So if you put two identical volumes side by side, the maximum information they can hold doesn't double. How does one explain that? Dauto (talk) 17:14, 8 November 2011 (UTC)

The way I read holographic principle, it "states that the description of a volume of space can be thought of as encoded on a boundary to the region." I don't pretend to know every possible mathematical consequence of that statement. However, as I mentioned above, we don't know if we can construct a valid description of any arbitrary volume and encode it on to the surface of that volume. At present, we only know how to do that for certain special cases, like the very simple case of stationary electric charge. I wouldn't be surprised if we run in to some logical conundrums if we try to extend this mathematical tool ad infinitum to try and describe every physical property: for example, consider magnetic fields. Their closed path integrals are pathological forgive the pun - they depend on the path you choose. Physical consequence? We can't even construct a coherent description of a "volume" of magnetic "charge" within the mathematical framework we use. (No magnetic monopole). We cannot use a surface-integral, nor a path-integral, to deduce a complete description of a magnetic field. It is a physical impossibility.

When our math and our physical observations clash, one or the other must be modified. So, if your assertion is correct, and placing two volumes side by side doesn't double some property, I see two ways to resolve this: (1) either the property is doubled, and you are mistaken; or (2) you are correct, the property does not double, but we can not conclude any physical conservation law for that property. Nimur (talk) 17:25, 8 November 2011 (UTC)

Or, put more succinctly: for all the handwaveyness of Brian Greene's pop-science books, he is essentially making one simple mathematical assertion: the Grand Unified Theory is specified by a curl-less field. That is a testable hypothesis, but it is not a fact. Nimur (talk) 17:36, 8 November 2011 (UTC)

You're looking at it the wrong way. Green's theorem is NOT one instance of the holographic principle because it says nothing about the maximum information content. Electrostatics isn't even a quantized theory so there is no limit to information content within Green's theorem. The maximum information content is infinite here, but that's irrelevant because as I pointed out it's not a quantized theory. The hlographic principle comes up when one tries to put Quantum mechanics and General relativity together and finds the surprising fact that the maximum information content of a region is proportional to the regions surface area. Dauto (talk) 17:59, 8 November 2011 (UTC)

Would this refute conventional scientific materialism, or simply suggest that our universe is a parallel universe to something inside the multiverse? ~AH1 ^(discuss!) 03:16, 9 November 2011 (UTC)

Neither. It possibly shows that the universe has one less dimension than what it seems to have. Dauto (talk) 19:26, 9 November 2011 (UTC)

That suggests a Planiverse of some sort. However my interpretation of the article was that observations suggest that events in this universe either take place in more dimensions than we can access, or that the cause of the images arises from a different universe, that which we cannot observe using our observational methods. ~AH1 ^(discuss!) 00:22, 10 November 2011 (UTC)

crazy cure for both AIDS and blood cancer

I've a doubt.In AIDS patients the white blood cells eventually died and causing low immunity.In leukemia patients white blood cells generate excessively.What if a guy has both diseases.The excessive white blood cells due to cancer is destructed of AIDS and an equilibrium forms.guy will be saved..please reply ?--nijil (talk) 17:19, 8 November 2011 (UTC)

Certainly not. You're taking a too simplistic view of those disease/cancer; see the articles leukemia and AIDS for a range of points. Grandiose (me, talk, contribs) 18:24, 8 November 2011 (UTC)

Your question is built on two ideas that don't connect well. In leukemia, the cancer cells don't function well (in part because they are immature), so they don't help fight infection; also, leukemia is generally a cancer of granulocytes and monocytes, which don't play the principal role in fighting viral infections. In lymphoma (a cancer of lymphocytes, the cells that fight viral infections and that are also the cells that HIV infects) the cancer cells are a clone - they have (at most) one specificity. If they functioned at all, it is vanishingly unlikely that they would be specific for an epitope of HIV, and even if they had such a specificity, the virus would almost certainly mutate to avoid them - as demonstrated when some clever people tried something like this to treat HIV - with disastrous results: PMID 7585062. -- Scray (talk) 19:28, 8 November 2011 (UTC)

While the above two responses explain why, in general, HIV infection would not be an appropriate or effective therapy to treat leukemia, it might be worth mentioning bone marrow transplantation as a potential cure for HIV infection. CCR5 is a protein that is naturally expressed on the surface of T cells, and its presence seems to be required for HIV to enter those cells. There is a known mutation, CCR5-Δ32, which confers resistance to HIV infection in people who carry it. People with two copies of the mutant CCR5 gene appear to be immune to (most strains of) HIV; about 1% of northern Europeans have this trait. In principle, one could use radiation and chemotherapy to wipe out a patient's original bone marrow (thus eliminating the supply of T cells that HIV can infect) and replace their marrow with HIV-resistant bone marrow from a donor with two copies of CCR5-Δ32.

Just such an approach was tested in Germany in 2007: Hematopoietic stem cell transplantation#Experimental HIV treatment. An HIV-positive patient with had developed leukemia (who therefore required a bone marrow transplant to cure that condition anyway) was matched to a bone marrow donor who carried the appropriate CCR5 mutations. Remarkably, the patient appears to be fully cured—of both diseases. That said, this solution won't work as a universal cure for AIDS. Finding a matching marrow donor who also carries the appropriate CCR5 mutation is difficult (and may be impossible for the majority of recipients). Bone marrow transplantation is a painful, risky procedure that will kill at least 10% of recipients, and is prone to other unpleasant complications. Consequently, this approach is only likely to be tried with patients who require a bone marrow transplant to cure another condition. TenOfAllTrades(talk) 01:38, 9 November 2011 (UTC)

The Vinca alkaloids are currently being used to treat leukemia. ~AH1 ^(discuss!) 03:12, 9 November 2011 (UTC)

source of elwha river pre dam chinook salmon numbers

What is the source of the estimates of the Elwha River's pre dam Chinook Salmon numbers? 400,000 Chinook is used as a factual number with no source for that number.The Elwha River has a gradient of over 80 feet per mile;which means to me that much of the river was impassable to salmon.Further this estimate is equal to or greater than the known runs of major,very much larger salmon streams. — Preceding unsigned comment added by 75.106.235.161 (talk) 18:19, 8 November 2011 (UTC)

The relevant article is Elwha River. Try Google Scholar. ~AH1 ^(discuss!) 03:10, 9 November 2011 (UTC)

aliens?

what would most likely happen if humans found alien life? Also, what is the slowest speed electricity will travel? Heck froze over (talk) 19:45, 8 November 2011 (UTC)

Depends on what type of alien life, and where we found it. Non-intelligent life (likely microbes) found in our solar system (on Mars, Europa, Enceladus, or other places) would be rigorously studied, its chemical make-up ascertained, its characteristics catalogued in extreme detail. For intelligent life, it would likely be lightyears away, so we'd need to devise a way to communicate with such beings, knowing that it would take years (possibly lifetimes) before we received any reply. --Goodbye Galaxy (talk) 20:07, 8 November 2011 (UTC)

a) Kill it, eat it, or otherwise find some way to profit from it.

b) Static electricity doesn't move at all.-- Obsidi♠n Soul 20:17, 8 November 2011 (UTC)

I think that he's talking about non-zero electrical current - if the electrons are moving from one point in a conductor to another point, how slow can they move to that point. Plasmic Physics (talk) 20:44, 8 November 2011 (UTC)

The electrical charge technically doesn't move much. It is merely passed along (in the usual form of electric "currency" - electrons, which good conductors like metals have in abundance). The apparent speed is the net total movement of the charge as the electrons are bounced along, but the individual electrons move only tiny distances (drift velocity). Like billiards or dominoes, atom 1 gets an extra electron, but atom 2 steals one from atom 1, atom 3 steals another one from atom 2, etc. In alternating currents, the atoms merely grab each other's electrons back and forth even. So the slowest electricity can go is technically the slowest net velocity electrons can achieve with their movements. What would seem like random movement of electrons to us for example may result in a net velocity that can only be apparent if you observe it for billions of years. Hence static electricity is a fair enough answer! :D ...I think... Physics make my nose bleed! The important question here is, would you eat aliens?! I have one for a low low price of $4.99! Order now and you can get a small vial containing 0.1 μg of prime quality moonrock for free!!! Perfect for alchemical experiments, picnics at the beach, love potions, good for your liver, and for curing those exotic diseases doctors don't even have names for! -- Obsidi♠n Soul 23:15, 8 November 2011 (UTC)

If my memory serves me right, physical electrons in a conductor move exceedingly slowly (order of mm/s). But the electric current is transmitted by the electormagnetic field and that moves at the speed of light.

A back of the envelope calculation: one Ampere current going through a copper wire with 1 mm^2 cross section would send 1.6*10^19 electrons per second through any cross section. If copper has one conductivity electron per atom, 1.6*10^19 electrons are contained in 0.00077 grams of copper, which is 0.087 mm^3, so the average speed of the electrons is 0.087 mm/s. --Itinerant1 (talk) 21:35, 8 November 2011 (UTC)

(think there should have been an EC)The answer to 2 is more complicated then it seemed to me at 1st, i'm not sure I can answer it.. The typical answer is that electricity travels at the speed of light, even if the charge carriers (typically electrons) are not going that fast. But to answer how SLOW it can go,.. A lightning strike for example propagates a LOT slower then the speed of light, about 140,000 mph (light is 670 million mph) but I think that's more to do with Velocity of propagation then with the speed of electricity, that complicates things a bit. Once a lightning bolt actually hits the ground, then the discharge actually happens at the speed of light.. So I'm not sure what the answer is, it seems like strictly electicity travels at the speed of light, but then what is a lightning bolt if not "electricity" travelling at 3000 times slower then light? Vespine (talk) 21:49, 8 November 2011 (UTC)

Electricity does not necessarily travel at the speed of light, but its speed is very high. If I recall correctly, the speed in many common coaxial cables is 2/3 of the speed of light. Lightning is not just a current flowing in a conductor. The lightning has to create a conductor on the way down, by ionizing the air in its path. It's not surprising that this produces a slower propagation speed. --Srleffler (talk) 18:48, 9 November 2011 (UTC)

If we find intelligent aliens, creationists still won't change their views. HiLo48 (talk) 21:52, 8 November 2011 (UTC)

You won't know unless you find some. Plasmic Physics (talk) 22:58, 8 November 2011 (UTC)

Yep, that's what's fun about hypotheticals. We're all allowed to speculate. HiLo48 (talk) 23:10, 8 November 2011 (UTC)

For example, if those highly-intelligent, highly-advanced E.T.'s believed in a supreme being (a god, or whatever), that would probably baffle the Richard Dawkinses of the world. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:25, 9 November 2011 (UTC)

Astrobiology is the current theoretical study of aliens. ~AH1 ^(discuss!) 03:02, 9 November 2011 (UTC)

We are "highly-intelligent, highly-advanced" compared to our ancestors, but there's no shortage of people who believe in god. So I'm not sure your statement is true.

OP, you want an answer based on history? If we find intelligent alien life, we'll kill the males, rape the females, and put whoever's left into concentration camps, Indian reservations, or factory animal farms. Humans will declare, as they've done countless times towards other humans and still do towards animals, that being similar to themselves is a requirement for getting basic rights. The aliens, logically, would not have basic rights and can be freely exploited or tortured. --140.180.16.167 (talk) 03:25, 10 November 2011 (UTC)

Expanding universe and conservation of energy.

A photon travels through extragalactic space. The universe expands, and the photon is redshifted. Where does that energy go? Goodbye Galaxy (talk) 20:00, 8 November 2011 (UTC)

Nowhere. Expanding universe is a prediction of general relativity. In general relativity, energy is not globally conserved. --Itinerant1 (talk) 20:03, 8 November 2011 (UTC)

Similarly, a train in motion has kinetic energy, but if you are inside of the train it seems to you to be at rest. Where does that energy go? Dauto (talk) 20:08, 8 November 2011 (UTC)

So the photon wouldn't redshift locally? Only relatively? Goodbye Galaxy (talk) 20:38, 8 November 2011 (UTC)

If the photon is kept in one place by reflecting it back a forth between to mirrors and the mirrors are kept at constant distance from each other than there will be no red-shift. Dauto (talk) 20:44, 8 November 2011 (UTC)

@Itinerant1: Not exactly. From my understanding, it depends on what kind of universe we live in as to whether or not General Relativity allows for universal conservation of energy. That is, under some closed geometries, the universe is considered a finite system, and may allow for conservation of energy to hold universally. If the universe has an open geometry, then conservation of energy may only hold in closed systems within the universe, but not across the entire universe. At least, that's my understanding of what it says at Conservation_of_energy#Relativity and Shape of the Universe. --Jayron32 21:05, 8 November 2011 (UTC)

Actually I think it's easier to define a global conserved energy in an open universe; you can put it on the boundary (at infinity). A closed universe has no boundary. There's some discussion of this in MTW. The difficulty is that total energy is the sum of all the local energies, i.e., the integral of the local energy over all of space; but (1) what's "space"? and (2) how do you add vectors defined at different points on a curved manifold?

Energy conservation is actually very subtle even in special relativity. Energy conservation in Rindler coordinates is different from energy conservation in inertial coordinates, and there was/is a guy who argued semi-plausibly that this disproved the equivalence principle (I don't have time to look up the details right now). -- BenRG (talk) 21:23, 10 November 2011 (UTC)

Why would an expanding universe cause light to redshift? ScienceApe (talk) 20:10, 8 November 2011 (UTC)

Woops, nvm. I realized the answer. ScienceApe (talk) 20:11, 8 November 2011 (UTC)

Perhaps the "energy" goes into either quantum energy or the metric expansion of space, neither of which are non-infinite in an open universe. ~AH1 ^(discuss!) 02:56, 9 November 2011 (UTC)

I don't see why anyone thinks the energy has "gone" anywhere. In its own frame of reference, the photon is not redshifted, it just has its normal energy. When observed from a great distance, the apparent frequency is lower because of intervening expansion, meaning that we observe a reduced energy, but that is just our observation. If we observe from the same place but with a high approach velocity, we don't see any redshift. Where has the "extra energy" come from? (I suppose you could say "from our own kinetic energy of approach", and "into metric expansion" for the static case, as suggested by AstroHurricane above, but isn't it just a quirk of observation?) Dbfirs 09:04, 9 November 2011 (UTC)

Dbfrs - I for one am having trouble following what you said. Can you explain what you mean by "in its own frame of reference" ? And also, what do you mean by "when observed from a great distance" - if this means measuring the frequency of a photon that is at a great distance away from us, how exactly do you make that measurement ? Gandalf61 (talk) 09:46, 9 November 2011 (UTC)

Yes, I got that wrong! I meant "in a local frame of reference". By measuring the frequency, I just meant noting the colour of the light. Dbfirs 16:42, 9 November 2011 (UTC)

So while a blue photon has more energy than a red one, light sources (sources of photons) receding from the observer would appear more red. The important question is redshifted relative to what, as there is no "centre" of the universe for an open model, which is what observations suggest. ~AH1 ^(discuss!) 00:18, 10 November 2011 (UTC)

... but Dauto's mirrors would provide a local frame of reference for comparison. Also, we know from cosmology and spectral analysis of stars what is the frequency of photons emitted at many sources. I agree that a photon in free space doesn't have a natural frame of reference. Dbfirs 07:42, 10 November 2011 (UTC)

Its my understanding that photons do not get red-shifted as they travel though space, which is probably not the correct way to view the red-shift, and thus these particles have never lost any energy (see tired light for theories which involve photons losing energy however). Instead, they have always had the energy which they were emitted with, but are measurably red-shifted only because of the relative speed between their emitters and us which is in proportion to the distance involved because of the expansion. Which means the more distant objects were moving away from us at relatively faster speeds. In short, photon energy is conserved because the red shift we measure is a large-scale relativistic Doppler effect. The expansion itself is increasingly more energetic and not less so, see accelerating universe, thus if we went back in time to an earlier Earth and took measurements, the measured distances, galactic speeds and their red shifts would not be as large. --Modocc (talk) 21:06, 10 November 2011 (UTC)

STEM shortage: education or raw ability?

To what extent does the shortage of scientists, technology professionals and engineers in the US result from a lack of access to education, and to what extent is it a shortage of raw ability (including the ability to retrain in adulthood)? What initiatives, if any, are underway to address the latter? NeonMerlin 21:59, 8 November 2011 (UTC)

There is no shortage of scientists in the US. There are tens of thousands of scientists willing to work non-tenure-track jobs for meager pay well into their 30's. They are called post-docs. I'd call that glut rather than shortage. Engineers are a different story. --Itinerant1 (talk) 22:10, 8 November 2011 (UTC)

There is a shortage of Engineers at the salary rate at which Capital would like to purchase their labour. I'd suggest to Engineers and prospective Engineers that maintaining the labour supply of Engineering at the current level works in their interest. Other professions where the labour supply was successfully expanded have been proletarianised. Fifelfoo (talk) 22:12, 8 November 2011 (UTC)

The OP postulates "a lack of access to education" or "a shortage of raw ability" as the two possible explanations for a perceived shortage of professionals. Another explanation is cultural. An old saying is that you can lead a horse to water but cannot make it drink. I'm a high school teacher and I see hundreds of kids every year not achieving to their potential simply because they don't care. Life is comfortable. They cannot be bothered putting in the effort to gain high level qualifications. Obviously that doesn't apply to all students, but to a sadly increasing percentage in western society. <Here endeth the lecture> HiLo48 (talk) 23:00, 8 November 2011 (UTC)

There are elements of class consciousness in the despair of students. When your workplace expectations are conditioned by the double hurdle of a proletarian and a menial work experience, it is difficult to imagine the freedoms at work and in income that engineers currently possess—that which is unimaginable but possible is not worth pursuing, especially when there are imaginable but improbable alternatives like the lottery or celebrity. My experience comparing a working class university with, frankly, bourgeois and managerial intake universities, is that working class students have smaller horizons of expectation, and go for safe professions with low incomes that they've seen directly modelled and repeatedly noted in culture; and, that they're aware from immediate experience are attainable and achievable. Nursing, Teaching, Accounting, Business or Arts to become a menial drone, IT rather than SEng CompEng or CompSci. Fifelfoo (talk) 01:22, 9 November 2011 (UTC)

There was an article on this in the New York Times just the other day. Education seems like an important juncture point — but not because of "lack of access," but because lots of people decide pretty quickly, once they are in college, to do something else. There is a lot that can be said about education other than "lack of access" — it can also be, "lack of preparation" or "unreasonable expectations" or things along those lines. Personally I suspect that the systematic de-skilling of primary and secondary school educators (thanks in no part to the terrible chase for standardized test scores, which leads to idiotic, standardized teaching) is partially responsible for this here. The college age students you are seeing now grew up under the terrible consequences of the No Child Left Behind Act, which has been systematically making public education a far more miserable and pointless affair than it has ever been previously (and it was always a bit pointless and miserable). But this is just conjecture on my part, to be sure. --Mr.98 (talk) 01:23, 9 November 2011 (UTC)

You may also be interested in Pygmalion effect and dyscalculia. ~AH1 ^(discuss!) 02:49, 9 November 2011 (UTC)

The engineering shortage is a smoke screen. But the sallary has to be higher than a commodity sallary and the workplace has to treat its employees right to induce an interest in students. Electron9 (talk) 03:42, 9 November 2011 (UTC)

This isn't true for a vast number of professions inculcated at Universities. Veterinarian incomes have crashed in Australia as the field has been feminised and veterinarians reduced from small capitalists to employees on salary. A similar process is happening with non-consulting doctors. A number of professions, (K-12, Nursing, Accountancy, HR) are at or below the average for employee remuneration, and are well below trade certified or diplomate trade salary incomes. Some merely skilled or unskilled occupations earn in advance of these professions. So it is untrue to say that a profession's salary needs to be above the average to induce an interest in students. Correspondingly, Nurses, Doctors, Social workers, Teachers and a whole host of professions are treated like shit in workplaces without any measure of workers' control and where management prerogative is absolute, and they still provide excellent service and inspire student interest. Fifelfoo (talk) 03:57, 9 November 2011 (UTC)

I want to reinforce the statement that there is no engineering shortage. There are many engineers in the United States who can't get jobs as engineers for many reasons. U.S. companies refuse to hire "old" engineers (by old, I mean more than 30 years old). Then, when they do hire an American engineer, he or she will ask for something ridiculous like $15/hr. The engineers from India and China will do the same job for $8/hr and put in 1.5 hours for every 1 hour paid. Basically, U.S. companies are creating the illusion of an engineering shortage so they can profit from government-sanctioned slave labor. -- kainaw™ 04:07, 9 November 2011 (UTC)

• In the US they like seasoned engineers getting $45 per hour to retire and make way for young engineers making far less. I question degreed engineers in India working for $8 per hour, let alone the 5.33 per hour if they work 1.5 hours for every book hour. Edison (talk) 04:28, 9 November 2011 (UTC)

I've never met an engineer who makes anywhere near $45/hr. $30/hr is around $60k/year. In government, commercial, and university places I've worked, managers will make over $60k/year, but not the engineers. Many engineers get an MBA and become managers - but they are no longer engineers. As for low-paid foreigners, I work with a guy from China who makes less than half what I make and puts in more hours. Why? He is on a work visa. He has a masters degree (and nearly finished his PhD). He actually took a pay cut to come to the U.S. and work. There are many more waiting to follow. When I leave, they will surely replace me with two more Chinese engineers. -- kainaw™ 04:34, 9 November 2011 (UTC)

HI! It's nice to meet you. Edison (talk) 06:05, 9 November 2011 (UTC)

I'm in IT and I've never seen any engineers who made less than $60k/year. (actually, no: I've seen a total of one, he was in his early 20's, and everyone I knew agreed that he was badly underpaid.) People whose wages I do know tend to make 6 figures. Admittedly, this is a relatively expensive place to live and most intelligent engineers, if offered $60k, would tell the recruiter to shove it.--Itinerant1 (talk) 11:17, 9 November 2011 (UTC)

P.S. On the other hand, just this week I saw a blog post that addressed this very subject (the apparent failure of US universities to produce enough STEM graduates) and seemed to conclude that the incentives for getting a STEM degree weren't great, seeing how you would have better prospects if you chose to get a degree in finance or work on your "soft skills", whatever that means. With regard to finance, the attitude was, to quote: "Why bust your hump in engineering, when a degree in finance will land you a 6-figures job on Wall St., and a shot at 7 or 8 figures, for about the same effort?" --Itinerant1 (talk) 11:26, 9 November 2011 (UTC)

A US salary survey shows, for 13 engineering disciplines, average salary + benefits ranging from $69000(biochemical) to $134000(petroleum). When industry cries that there is a "shortage of engineers" I am reminded of th"The Grapes of Wrath" (a historical novel about the Great Depression in the US) where displaced farmers get excited about handbill stating that there are "lots of jobs for fruit pickers" in California. When they get there, they find that there is a surplus of pickers, and the growers just wanted lots of job applicants to drive down the wages. I believe this has always been the desire of employers: to make sure there is a surplus of engineers, so they can keep salaries as low as possible. Even with the high wages, companies get piles of job applications from unemployed engineers. Edison (talk) 16:04, 9 November 2011 (UTC)

Making suet for birds at home...

As winter has arrived where I live, I would like to try making some suet. It seems simple enough. However, I have two questions:

1. Will pork fat do or must I use beef fat? Where I live the former is abundant and the latter hideously expensive.

2. Does it really need to be strained 2+ times through cheesecloth? What is being strained out during this step?

If anyone has any general tips on making suet for backyard birds, I'd also like to hear them. Thank you! The Masked Booby (talk) 22:18, 8 November 2011 (UTC)

I don't know anything about suet, the article seems to say specifically that you need beef fat, but, if you want to use pork fat, you could make Salo instead, and birds like that too. --Itinerant1 (talk) 22:26, 8 November 2011 (UTC)

The difference is that beef abdominal fat, if pure enough, will harden almost to the consistency of wax, and doesn't easily melt. Pork fat is soft and greasy even when it is cold. Nutritionally they are pretty much equivalent, but the texture is very different. Looie496 (talk) 22:46, 8 November 2011 (UTC)

Salo is hard enough that you need to cut it with a knife. As far as I understand, fat only becomes soft if it is rendered and purified. In its raw form, as salo or suet, it is quite firm because it is kept together by cell walls, and you need the temperature above 100 C to break them. But you are correct that purified pork fat is softer and its melting point is at least 10 C lower than the melting point of beef fat. --Itinerant1 (talk) 23:11, 8 November 2011 (UTC)

Maybe you missed it, the suet article actually says in the bird feed section Bird feed is commonly used in the form of cakes of suet, which can be made with other solid fats, such as lard. and the reference given has the instructions of how to make it with lard. Vespine (talk) 01:10, 9 November 2011 (UTC)