Wikipedia:Reference desk/Archives/Science/2014 January 8

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January 8

HbA1c

Why is the "HbA1c" designation given to Glycated hemoglobin, i.e. why isn't it called something else? I understand that "Hb" stands for hemoglobin, but I can't figure out what the significance of "A1c" is. Since I know that HbA1b, HbA1d, HbA2c, HbB1c, etc., are all redlinks, I assume that it's not something sequential, and I know it's not a typo for HbAlc. Nyttend (talk) 01:51, 8 January 2014 (UTC)

We did this a month or two ago, I think. Turns out it's not Hb A1c but rather HbA 1c — that is, subtype 1c of hemoglobin A. I think there are probably subtypes 1a and 1b as well, but maybe just no one's gotten around to writing about them. But anyway if you search the archives it should show up. --Trovatore (talk) 01:59, 8 January 2014 (UTC)

Here you go: Wikipedia:Reference_desk/Archives/Science/2013 September 5#What is the meaning of A1C?. Look down for Nunh-huh's response; it looks like the most informative. --Trovatore (talk)

HbA = adult hemoglobin HbF is fetal hemoglobin HbA1a1 with fructose 1,6 diphosphate HbA1a2 with glucose 6 phosphate. Graeme Bartlett (talk) 02:12, 8 January 2014 (UTC)

Timber bridges

Cable-stayed Pomeroy-Mason Bridge in the USA

Why is it that timber is not used in bridges which require high loading capacities other than as decking? I am presuming it is because timber does not take axial load as well as rebar does but in the case of decking it is acceptable as it is likely to have more bending moments than axial loads, and timber takes bending moments better than concrete or rebar. Clover345 (talk) 15:57, 8 January 2014 (UTC)

Please define "high". Covered bridges went out of favor (from a structural perspective, not from an æsthetic or historic-preservation perspective) because they were more expensive than iron or steel in most places, and you also have the issue of timber being harder to produce in sizes that are good for long bridges. Imagine how hard it would be to get all the right timbers for something as large as the George Rogers Clark Memorial Bridge, for example. Nyttend (talk) 16:16, 8 January 2014 (UTC)

Also maintenance can be an issue. Steel just needs rust protection, and regular painting can prevent that. Wood, on the other hand, is vulnerable to dry rot, termites, burrowing beetles, woodpeckers, water damage, fire, etc. So, there's a lot more maintenance needed to keep wooden bridges in good working order. StuRat (talk) 18:09, 8 January 2014 (UTC)

As a terminological note, bridges aren't made of rebar, they are made of structural steel (Ok, maybe some people bridge their backyard creeks with rebar, but I suspect you're thinking about much larger bridges). The name "rebar" is generally reserved for unfinished, small diameter steel rods that are used in reinforced concrete. The structural steel article has a nice section comparing the pros and cons of steel compared to reinforced concrete.

As for your main question, there isn't much about timber bridges at bridge, but it does point out that most early bridges were not timber-only, but also used large amounts of masonry for structural load bearing. Timber bridge mentions that they are regaining in popularity in some areas, and has some good refs and external links, indicating they are currently used for high loads (i.e. automobile traffic), albeit for relatively short spans. The article and refs claim a ~50 yr life span, and comparable or reduced costs of construction and maintenance compared to other materials. Finally, timber is a renewable resource with (generally) lesser environmental impact than steel or reinforced concrete, and some governments might find that favorable. SemanticMantis (talk) 19:03, 8 January 2014 (UTC)

Steel and concrete don't seem like things we will run out of any time soon, being made from basic ingredients like iron, carbon, sand, lime, etc., which are abundant on the Earth. They also aren't particularly harmful to the environment, as the steel will rust away and the concrete break back up into rocks, in a few decades. StuRat (talk) 21:29, 8 January 2014 (UTC)

Off-topic rebuttal to Stu's speculation - SemanticMantis (talk) 22:16, 8 January 2014 (UTC)

:::I never said we were running out of steel. But it is not considered a renewable resource. That is not really up for debate. Also, you could have done a little googling about concrete, or even looked at our own environmental impact of concrete, which says "The cement industry is one of the primary producers of carbon dioxide, a major greenhouse gas." Additionally, the article outlines other detrimental environmental effects due to altered runoff patterns which can increase flooding, as well as urban heat island effects. I also did not say that concrete was commonly considered a pollutant. The key idea is that it takes massive amounts of energy to make steel and concrete, which generally adds to our global CO_2 emissions. In contrast, growing trees for timber removes CO_2 from the atmosphere, and can in some cases timber production can be considered a carbon sink, which is a technique for climate change mitigation. See also life cycle analysis. My point is, your statement that concrete isn't particularly harmful to the environment is just wrong, from several perspectives. Now I've gotten far off topic, so I'll quit :) In the future, please read my words and links carefully before you try to contradict them, or at least bring something besides your own assertions to the table. SemanticMantis (talk) 22:09, 8 January 2014 (UTC) And while timber can be grown in a sustainable manner, it often isn't, with clear-cutting, cutting of old growth forest, and deforestation being the result. Even growing it in a sustainable manner requires adding access roads, which also gives access to hunters (whether legal or poachers), endangering wild animal populations. And the fact that timber bridges aren't likely to last as long means that the extra replacement bridges need to be figured into the environmental cost. StuRat (talk) 14:00, 9 January 2014 (UTC) If CO2 is a "major greenhouse gas" like you say, and its levels are at an all-time high as they are, then why is it that we're freezing our butts off in the coldest winter since 1944??? 2601:9:3200:467:6109:95AD:B0F7:600D (talk) 02:15, 9 January 2014 (UTC) If you'd like to ask questions about climate change, feel free to open a new thread on the science desk. You can start by reading our articles on climate change, greenhouse gas and carbon dioxide. Also, at a basic level, you are confused about what is weather and what is climate. SemanticMantis (talk) 03:38, 9 January 2014 (UTC)

[ec with StuRat] Also please note that concrete and steel can be used to build bridge types that aren't timber-suitable. Timber can work well for a truss bridge, but a cable-stayed bridge (see picture) and a suspension bridge really need other materials. Nyttend (talk) 21:34, 8 January 2014 (UTC)

To reduce costs during construction, the railway viaducts in Cornwall (England) were initially wood and there is quite a comprehensive article on them at Cornwall Railway viaducts Widneymanor (talk) 21:37, 8 January 2014 (UTC)

Didn't you mean the railroad trestles in the 19th-century American Midwest? 2601:9:3200:467:6109:95AD:B0F7:600D (talk) 02:17, 9 January 2014 (UTC)

• Look here [1]. lots of examples. --VanBuren (talk) 14:53, 9 January 2014 (UTC)

Repetitive driving but not Highway hypnosis

I was reading the Highway hypnosis article thinking it would be describing a common phenomenon I am familiar with but it didn't. I googled the term and could not find any references to what I, and I'm sure many others have experienced. I'n not sure what to call it... "Stop and Go hypnosis"? I only ever experienced it when I was in high school (I'm quite a bit older now). It was always during rush hour and very little attention was really involved, just follow the car in front of me until I get to my destination (it was a pretty simple route). Most mornings I would at some point become aware that I had arrived at my destination without any memory of the drive there. It seems like I would "zone out" and "Viola!" I was at school. It was a very repetitive boring task and only happened in the morning when I was tired. This seems quite unlike what is described in the Highway hypnosis article as I would still have had to obey traffic lights and the flow of traffic without ever so much as a fender bender or even a close call. It seems the task had become so repetitive that my mind "decided" there was nothing novel about it and hence no new memories to form. I'd be interested to hear form others who have experienced this or if anyone has run across a name for the phenomenon I am describing for which perhaps there is no Wikipedia article for, or perhaps the information is in an article I cannot find.  — TimL • talk 21:16, 8 January 2014 (UTC)

Yes, I've experienced that. And a twist is where you must take most of a common route, but then take a turn near the end to arrive at a different destination. I find it quite difficult to make that turn, as my brain "goes on autopilot" and I arrive at the more usual destination. I suspect a different part of the brain is guiding my driving in that mode, where rather than reasoning out turns and such, it's simply going off memory. StuRat (talk) 21:23, 8 January 2014 (UTC)

Ah yes, that too I have experienced (a common route with with a different turn for a different destination), I have at times in the past found myself driving to one destination when I meant to drive to nother if they involve a same comon route.  — TimL • talk 21:34, 8 January 2014 (UTC)

My uncle used to have a job that required him to drive to two different locations depending on which day it was. He had a note card on his dashboard that had an arrow on each side pointing in opposite directions. To remind him of which direction he should turn out of his driveway each morning, he would flip the card over the previous night. Dismas|^(talk) 21:52, 8 January 2014 (UTC)

One of the main stretches I drive to go anywhere has four lanes, so I just have to remember to put myself in a different lane than the one I normally use for my commute if I'm going somewhere else. If I don't I'll end up at home or at work. Once, driving in from out of town I was on a road that used to be on my route to work and ended up automatically driving to my old apartment. The other thing about this "autopilot" mode that gets me is when something snaps me out of it on a rural route and I realize I don't actually know what road I'm on because I don't remember the last few turns. Katie R (talk) 13:35, 9 January 2014 (UTC)

(edit conflict)It's common enough that I was taught about it in Driver's Education back in the early 90s. And I've heard several people, both in my personal life and on television, talk about the idea of having gone through a stop sign knowing that they stopped but can't remember actually doing it. All because they've done it thousands of times before. I can't recall ever hearing a name for it though. Dismas|^(talk) 21:24, 8 January 2014 (UTC)

This Reader's Digest article talks about it some. And Yale researchers have looked into it. Though I still can't find a name. Dismas|^(talk) 21:30, 8 January 2014 (UTC)

Thanks. Your references seem to suggest it is a pretty common but little studied phenomenon. It's almost as if I was a philosophical zombie on those morning drives! I suspect we all are for short periods of time.  — TimL • talk 21:48, 8 January 2014 (UTC)

For the general phenomenon, see automaticity, which is the term used in psychology. Our article lists highway hypnosis as an example. Even though your example is different, it is, to my understanding, still an example of automaticity. If I had to talk about it in a formal setting, I might call it "automaticity of city driving". If you search google scholar for various combinations of /automaticity driving memory/ you will find some relevant articles. SemanticMantis (talk) 23:59, 8 January 2014 (UTC)

Perhaps Automaticity applies here, but thing is, it's not just that I had "automated" driving to school and thus didn't need to think about what I was doing, it was more like I was driving to school without any awareness at all!  — TimL • talk 00:29, 9 January 2014 (UTC)

• It's a form of amnesia. The highway hypnosis article mentions it, but very briefly. Looie496 (talk) 00:47, 9 January 2014 (UTC)

That makes sense to me, it certainly feels that way. "Common route amnesia"?  — TimL • talk 01:10, 9 January 2014 (UTC)

Check it out, automaticity has been suggested to be moved to procedural memory. There's a subsection there, Procedural_memory#Expertise-induced_amnesia, that I believe describes this phenomenon very well. But this is not my area of expertise. Any thoughts (User:Looie496)? SemanticMantis (talk) 03:30, 9 January 2014 (UTC)

Automaticity does seem to describe this common phenomenon of driving a familiar route and not remembering it. If something unusual happens, such as an accident (hopefully not involving you), that will catch you attention because it's not part of the standard routine. I don't see this quote in the article, but I'm reminded of one of Yogi Berra's statements: "Ain't nobody can think and hit at the same time." An athlete trains himself in the mechanics so he can focus on the dynamics of a given situation rather than on the basics of "how to" do something. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:53, 9 January 2014 (UTC)

Um, well, I don't actually know a whole lot about this. But that subsection looks like Original Synthesis to me, so I wouldn't say it forms a good basis for a move. Looie496 (talk) 04:54, 9 January 2014 (UTC)

The one difference is I had to be "half-asleep". I could always remember that I drove home, if not the drive itself. In the morning it was have if the drive had never happened, a somewhat disturbing phenomenon at first. It was a "How did I get here if I don't remember anything about the drive here?" sort of experience. It was more like an "automation coma" if I had to coin a term!  — TimL • talk 11:19, 9 January 2014 (UTC)

Yes, being sleepy does seem to figure in. Presumably the conscious part of the brain goes to sleep while the automatic part stays awake. I noticed when I took caffeine pills to stay awake for late night drives, this happened. That is, the caffeine kept my eyes opened, but the conscious part of the brain seemed to zone out. StuRat (talk) 13:44, 9 January 2014 (UTC)

It doesn't necessarily have anything to do with sleepiness. It can happen if you are intensely thinking about something unrelated while you are driving. It's just that either your episodic memory system doesn't form a record of events, or else that record is not easily accessible afterward. There isn't a whole lot of literature about this, but if you do a Google Scholar search for the phrase "driving without attention mode" (the name it was given by JS Kerr in a 1991 paper), you can find a few things. Looie496 (talk) 17:21, 9 January 2014 (UTC)

Thanks. I found the article Driving Without Attention Mode by May and Gale which appears to describe exactly the phenomenon I have experienced.  — TimL • talk 01:49, 10 January 2014 (UTC)

It is not just driving, it happens when you walk to work every morning as well. I cannot remember walking all the way to this building today, but I know I must have, since I am here. --Lgriot (talk) 09:26, 9 January 2014 (UTC)

• I have always called this phenomenon of not consciously driving, driving on the reptilian brain. You can also witness its effects in other people. I normally try to drive at a constant speed slightly above the speed limit, and to avoid having a driver directly ahead of me. This means I am often either passing or being passed.

But you will notice on occasion someone will pull up behind you and just hover there, even in a relatively open road, where they could pass or at least switch lanes. You'll notice that if you gradually speed up or slow down they will stay with you. You can even gradually slow down to 10 or miles below the speed limit. As long as the road is mostly empty, and they don't notice others passing, they will stay in place behind you for quite a bit. It is like they have joined your herd, and placed you in the role of lead stallion, so that they can turn their minds off and parasitize on yours.

After this has gone on for some while, you can break the spell by turning on your emergency blinkers. This has the brief effect of making it look like you have slammed on your breaks, although you haven't. They will also often then hit their brakes. Almost always they will then accelerate and pass you, often with a nasty, "you woke me up!", look. μηδείς (talk) 19:24, 9 January 2014 (UTC)

• This is completely off-topic (sorry) but another phenomenon I have experienced is microsleep while driving. I often drove across the state of Florida (while in college on the other coast) while extremely fatigued and would find myself "coming into awareness" whenever my car started to drift out of the lane. I was certainly imperiling my life and the life of others, but I know I am not the only one!  — TimL • talk 01:59, 10 January 2014 (UTC)

This was discussed recently at [2]. (Incidentally, I started to feel drowsy on another trip and tried a related approach, namely, trying to recall details about the layout of a campus from undergraduate days, which seemed to work just as well as the job interview question approach or listening to political news. It strikes me that what the first two might have in common is that they call on long term memory, while the third seems prone to yield future arguments that become worth storing in memory. When I try to recall dreams it seems like there's a sort of incompatibility between memory and sleep, so I'm thinking there could be some idea there. But "automatic" memory, like singing a familiar song at the top of my lungs trying to stay awake, doesn't interfere with drowsiness much at all. Wnt (talk) 07:12, 10 January 2014 (UTC)

Text to 90999

The Red Cross says to do this to help people.

I looked at text messaging and I'm not sure this type of text messaging is described there.— Vchimpanzee · talk · contributions · 21:43, 8 January 2014 (UTC)

It is described at Mobile donating. I'll take a look at text messaging article to see if there is any reference to the mobile donating article. I googled "text messaging donations" to find the Wikipedia article.  — TimL • talk 21:53, 8 January 2014 (UTC)

I found what I needed at short code. Thanks.— Vchimpanzee · talk · contributions · 22:01, 8 January 2014 (UTC)

Just to note that up to 50% of the "donation" goes to the mobile service providers. It's better to donate via the organization's website.--Shantavira|^{feed me} 09:37, 9 January 2014 (UTC)

All of these "Text XYZ to ###" messages are best ignored. They are unhelpful at best and complete scams at worst. If you really want to donate, either spend a lot (say >$100 via conventional means), or if you cannot afford that, don't donate and save for the next time. Paying for text messages to donate miniscule amounts is a waste. Somewhat off-topic, sorry, but in the long run it will get millions to the right places, rather than mobile network providers.217.255.149.135 (talk) 10:13, 9 January 2014 (UTC)

Not true. The only amount that goes to the carriers is whatever extra fee they charge for the text, if any. From www.mobilegiving.org, "100% of each donation is remitted directly from the wireless operators to the Mobile Giving Foundation, which in turns gives 100% to the recipient charity". mgive.org which the Red Cross uses has the same stipulation [3]  — TimL • talk 11:12, 9 January 2014 (UTC)

I'm pleased to see there are exceptions. I see that you have removed well referenced information from the mobile donating article. This is the referenced page, and although it was written a few years ago, the general situation is very unlikely to have changed; it would have been highly publicized if it had.--Shantavira|^{feed me} 08:28, 10 January 2014 (UTC)