Wikipedia:Reference desk/Archives/Miscellaneous/2020 December 26

= December 26 =

Why aren't car engines always x.x99 liters?
Do some countries tax x.999 liters the same as x+1.000? The Bugatti Chiron is 7.993 liters, would it really cost significantly more if it was 7.999 liters or even 8.001 liters? If I could afford the world's most powerful car I would want at least 8.001 liters so I could say it was over 8 liters. Sagittarian Milky Way (talk) 02:46, 26 December 2020 (UTC)
 * Higher tax bands generally start at exact litre, half-litre, or at finest 1/10-litre (10cc) displacement measures. Engines are therefore usually built to just under those measures to remain in a lower tax band. However, actual capacities can vary slightly in manufacture or with the fitting of replacement parts (such as new cylinder heads or piston sleeves), and piston rebores will also increase capacity slightly, so to avoid crossing the tax threshold, the actual deliberate "undershoot" is usually at least 1cc if not more.
 * That said, I suspect that where cars like the Bugatti Chiron are concerned, taxes are not a consideration and other engineering factors are responsible for the capacities designed into them. Perhaps others can elucidate. {The poster formerly known as 87.81.230.195} 2.122.56.237 (talk) 07:46, 26 December 2020 (UTC)
 * Of the 26 engine models listed at, eight (31%) have an engine displacement of X.99+ litres; if these displacements had resulted as optimal data points for a mix of primarily engineering considerations, this would occur with a probability of less than one in a billion. Whatever the reason, clearly the displacement is often a parameter given as input to the designers, and for some reason values just below a whole number of litres are a favourite. --Lambiam 13:04, 26 December 2020 (UTC)
 * Taxations in picky European and Asian countries. Carbons should be taxed instead. Sagittarian Milky Way (talk) 14:40, 26 December 2020 (UTC)
 * A car engine's carbon (and other) emissions change (usually upwards) over its lifetime, and possibly with its state of maintenance: accurate carbon taxing would therefore require the car's emissions to be regularly tested, presumably annually. This is compulsorily done for nearly all road vehicles over 3 years old in Great Britain, 4 in Northern Ireland (except for vehicles registered more than 40 years ago that have not been substantially modified in the last 30). In some other countries, however, the infrastructure and procedures necessary for this might not be very easy to provide. {The poster formerly known as 87.81.230.195} 2.122.56.237 (talk) 19:39, 27 December 2020 (UTC)
 * Most cars of some ages have to pass emissions maxes to be US-legal too, probably not carbon though. If you pass they give you a windshield sticker in the colour of your expiration day so the police know when to fine you. Sagittarian Milky Way (talk) 20:33, 27 December 2020 (UTC)
 * An easy way to tax the carbon without having to measure emissions is to tax the carbon in the fuel. --Lambiam 23:31, 27 December 2020 (UTC)
 * In the UK, engine emissions are taxed through Vehicle Excise Duty (I believe based on the emissions when the engine is new) and there's tax on petrol and diesel fuel, which currently amounts to about 65% of the pump price.  Alansplodge (talk) 12:30, 28 December 2020 (UTC)

Typo in Recent human evolution
One sentence of this article is At at first birth is a highly heritable trait. I don't know what the author meant to write. Can anyone help? 58.186.52.251 (talk) 13:33, 26 December 2020 (UTC)
 * That's from Recent human evolution. The first "At" is a typo for "Age".  Corrected.  Pinging editor User:Nerd271. -- ToE 14:19, 26 December 2020 (UTC)
 * Thank you for proofreading! Yes, that was what I meant to write. Nerd271 (talk) 20:50, 26 December 2020 (UTC)
 * I can certainly confirm that the first time I was born I was 0, as were my mother and father before me. Matt Deres (talk) 15:13, 26 December 2020 (UTC)
 * Assuming you are not joking, birth here is short for childbirth. Nerd271 (talk) 20:50, 26 December 2020 (UTC)
 * Everyone is at age 0 at childbirth, which is about as heritable as it gets. ←Baseball Bugs What's up, Doc? carrots→ 23:16, 26 December 2020 (UTC)
 * Not the mother, whose age at her first childbirth is the topic at hand. Nerd271 (talk) 00:01, 27 December 2020 (UTC)
 * Sigh, it's this kind of smart-arsery that'll only confuse people, especially non-native speakers. The question was obvious, what's the point in taking the piss? Fgf10 (talk) 11:55, 27 December 2020 (UTC)
 * Ah, so the IP was indeed a non-native speaker of the English language, not just a newcomer to Wikipedia. I agree. This sort of "humor" at the expense of non-native speakers and newcomers is unbecoming of people at the Reference Desk of Wikipedia. Nerd271 (talk) 16:34, 27 December 2020 (UTC)
 * To obviate future non-native-English reader confusion, I have amended the sentence to read "Maternal age at first birth is a highly heritable trait." I note, however, that the sentence in question is the last in a paragraph which is clearly discussing the age of mothers at first birth, rather than that of the children, so it was not obvious that there could be any confusion. {The poster formerly known as 87.81.2300.195} 2.122.56.237 (talk) 19:48, 27 December 2020 (UTC)
 * There was nothing wrong with the article (other than typo) or the question here. My remark referred to certain posters here deliberately "misunderstanding" obvious questions for "humorous effect". Fgf10 (talk) 10:08, 28 December 2020 (UTC)
 * To obviate future non-native-English reader confusion, I have amended the sentence to read "Maternal age at first birth is a highly heritable trait." I note, however, that the sentence in question is the last in a paragraph which is clearly discussing the age of mothers at first birth, rather than that of the children, so it was not obvious that there could be any confusion. {The poster formerly known as 87.81.2300.195} 2.122.56.237 (talk) 19:48, 27 December 2020 (UTC)
 * There was nothing wrong with the article (other than typo) or the question here. My remark referred to certain posters here deliberately "misunderstanding" obvious questions for "humorous effect". Fgf10 (talk) 10:08, 28 December 2020 (UTC)