The Science Thread

from der wiki.

Accusations of industry influence

One notable critic was Ralph Nader who said, "ACSH is a consumer front organization for its business backers. It has seized the language and style of the existing consumer organizations, but its real purpose, you might say, is to glove the hand that feeds it."

Originally Posted by Ripper
Can you give some examples?

I'm on holidays in Japan for another three weeks so don't have details with me. One I had personal experience with was papers for the leading general computing journals, CACM for example, classing 3-5 students tests of a new UI as acceptable but rigorous multi-company industry blind testing with over 100 people as ’biased’.

Another, the leading information systems journals don't accept most research around technology adoption unless it uses an old, superseded model called TAM. Why? Citations are King and if a new model is used their previous citations counts will reduce.

Originally Posted by Hurls
Another, the leading information systems journals don't accept most research around technology adoption unless it uses an old, superseded model called TAM. Why? Citations are King and if a new model is used their previous citations counts will reduce.

What? That sounds really horrible. At some point journal articles will have no citations and you will be expected to accept data at the articles words.

Originally Posted by Hurls
I'm on holidays in Japan for another three weeks so don't have details with me. One I had personal experience with was papers for the leading general computing journals, CACM for example, classing 3-5 students tests of a new UI as acceptable but rigorous multi-company industry blind testing with over 100 people as ’biased’.

Another, the leading information systems journals don't accept most research around technology adoption unless it uses an old, superseded model called TAM. Why? Citations are King and if a new model is used their previous citations counts will reduce.

So, when you say they're ideologically driven, you mean in terms of their own practices, rather than undue political influence?

Yes, nice description @Ripper

I'd still call it ideologically driven or is that idiotologically driven

An undiscovered ninth planet in our solar system…?
https://www.theguardian.com/science/…beyond-neptune

Apparently it's one hypothesis for the unusual orbit of a newly found asteroid. If I'm remembering my Brian Cox correctly, this was once also a (now disproved) hypothesis for Mercury's elliptical orbit. Very interesting stuff though.

Originally Posted by Pongo
An undiscovered ninth planet in our solar system…?
https://www.theguardian.com/science/…beyond-neptune

Apparently it's one hypothesis for the unusual orbit of a newly found asteroid. If I'm remembering my Brian Cox correctly, this was once also a (now disproved) hypothesis for Mercury's elliptical orbit. Very interesting stuff though.

Yes, this is an idea that's been taken seriously for a while now. Some scientists are now actively looking for it.

Originally Posted by Ripper
Yes, this is an idea that's been taken seriously for a while now. Some scientists are now actively looking for it.

Quite interesting. I suppose that that far out in the Kuiper belt there could be more, we've probably found only a minority of the things out there.

pibbur who observes that this is not the imaginary and non existing planet Nibiru which is supposed to have caused cataclysms on earth several times this century.

They already have a presumed orbit for it.

Too bad we don't have any sensors measuring this solar system's belts. Voyager is already too far away, and its data would be difficult to get these days.

The two different types of water isolated.

http://www.bbc.com/news/science-environment-44305663

Saltwater and non-salt water ?

And now probably pibbur jumps in, swaying : "But we scientists know about that for a decade now".

No, actually two different fundamental types of H2O. Depending on the spin of hydrogen protons, you get small but measurable differences - the different water molecules can react differently with other substances.

Wouldn't that be true for *any* kind of matter ?

Originally Posted by Alrik Fassbauer
Wouldn't that be true for *any* kind of matter ?

Yes, molecules that differ in their atomic arrangements are called isomers, and there's loads of them. They've just not been able to isolate the types of H2O before. This is probably because, whereas most elements have multiple protons and various ways to be configured differently, hydrogen has only one proton. So, if the only difference is the spin of single protons, the difference is very subtle.

Edit: Well, I don't know if Pibbur will "jump in", but probably he is not too surprised by this - isomers are significant in medicine.

tl;dr: sugars are examples of isomers in our bodys. IOOsomers are handled differntl
Here comes pibbur.

No,I didn't know about the two water isomers. But I know a bit or two about biologically important isomers.

Let's consider sugar. (The following is a simplified explanation, leaving out a lot of details.)

There are large sugar molecules like starch and cellulose. These are long chains of simpler building block called monosaccarides. The most important monosaccaride is glucose, which has the general formula C6H12O6, 6 carbon atoms, 12 hydrogens and 6 oxygen atoms. Glucose is an example of a hexose (from hexa, 6), a sugar with 6 carbon atoms. There are however other hexoses , the most important of these are fructose and galactose. These have the same general formula, but hey differ from each other in how the atoms are arranged.



It's easy to see the difference between fructose and the other two, since fructose has a 5-ring, the other to are 6-ring structures. The difference between glucosis and galactosis is more subtle, but if we look at the leftmost carbon atom we see that the OH-group is directed upwards for galactose and downwards for glucose, just a small small variation but as we shall see, biochemically very important. These 3 molecules are isomers, more specifically structural isomers.

The reason why these differences matter is how enzymes work. Enzymes are very specific when it comes to the substances they can work on (and what they can do with them). Breaking down glucose in our cells is a chain reaction with around 20 separate steps, all controlled by it's own enzyme. The enzyme glucokinase takes care of the first step in this process. This enzyme can only handle glucose, not fructose or galactose which therefore are handled differently, but both fructose and galactose can be transformed to glucose.

We see another type of isomerism if we look closer at the glucose molecule. Turns out there are two forms of glucose, D-glucose and L-Glucose. These are mirror images of each other, and like other mirror images, you can't get one form from the nother just by rotating it. The D-form and L-form are stereoisomers. Only the D-form occurs naturally, because - surprise, surprise - our enzymes can only handle the D-form. The L-form has to be made in a lab.



There are other types of monosakkarides. A pentose is a sugar molecule with 5 carbon atoms (penta=5). One of the important pentoses is deoxyribose, which together with phosphoric acid construct the backbone of our DNA molecules (DNA stands for deoxyribo-nucleic acid). Pentoses and hexoses are not isomers since the numbers of atoms differ.

pibbur who observes that some of his typos can be considered isomers, since all the required letters (and no others) are there, it's just the sequence that differ. Not all of them, though. *sighs* And this is a very long rant.

PS. Alrik: I see that some of my responses to several of your posts, have been a bit patronizing and arrogant. I'm sorry for that. That was not my intention. Friends again?DS.

This type of isomer involved in hydrogen (and water) seems to be a different type of beast. The stucture is the same, and the neutron weight is the same, so it's not an isotope. It seems to be differentiated only by the quantum spin of the hydrogen proton pair - do you know of any other isomers of this type?

No, first time I heard about it.

I wonder if this could affect, or be used in MR imaging, since magnetic resonance is based on the spin of hydogen nuclei. This short article discusses the matter: https://www.chemistryworld.com/news/…000906.article, The conclusion is that it may affect magnetic resonance, but not in MR imaging, at least not directly. We'll see.

pibbur

Now, it would be interesting to see if we have both forms inside of us as well …

No, the L-form doesn't occur naturally. Now higher organisms (our food sources) can handle it and we can't make it ourselves.

Some bacteria metabolise it, one example is the plant pathogen Burkholderia caryophylli.

BTW, it does taste as sweet as D-glucose. Thus it could be a perfect sweetener, but manufacturing cost is very high, so it's not commercially feasible.

pibbur who …