Wikipedia:Reference desk/Archives/Science/2022 April 29

= April 29 =

Crocus in snow
Hi. It happens sometimes during spring to see a meadow under snow with Crocus plants sprouting in the middle of the snow, while the snow seems to have melted around the stems of the plants. Does the crocus generate heat, or is it heat from the sun (or from the ground) funneled through the stem? Or something else? See e.g. https://www.gettyimages.de/detail/foto/close-up-of-purple-crocus-flowers-lizenzfreies-bild/1158770267 Thanks 2003:F5:6F0B:F000:8C19:F1C6:40C1:4EBE (talk) 14:40, 29 April 2022 (UTC) Marco PB
 * Some plants do generate their own heat (the plant equivalent of being "warm blooded"). See Thermogenic plant.  No idea if crocuses are or are not.  -- Jayron 32 14:46, 29 April 2022 (UTC)
 * The crocus stem is darker than the snow, perhaps it absorbs more radiation from the sun so is slightly warmer than the highly reflective snow? Martin of Sheffield (talk) 15:17, 29 April 2022 (UTC)
 * That is one of several effects mentioned in this long paper Thermal Ecology of Flowers. It only mentions crocuses once, though, in an inconclusive experiment to do with stopping them closing at night. Card Zero  (talk) 17:39, 29 April 2022 (UTC)
 * "Thermogenic" also seems to be a woo-woo word to do with health supplements, annoyingly, and these include some sort of saffron extract (which is crocuses), so searching gives me a poor signal-to-noise ratio and a lot of "best thermogenics - buy now". Card Zero  (talk) 17:43, 29 April 2022 (UTC)
 * You are probably seeing the snow crocus (Crocus chrysanthus) or its relative, the spring crocus (Crocus vernus), both early bloomers, just like members of the snowdrop genus (Galanthus), called kardelen (snow-piercing) in Turkish, which likewise can emerge from a snow cover. I think the metabolism of the plant generates a negligeable amount of heat, so I suspect that there being a hole in the snow cover, once the snow has been pierced, is already a sufficient condition for the hole to widen in temperatures that are just above 0°C, well before holes appear spontaneously in the intact parts of the cover. --Lambiam 19:35, 29 April 2022 (UTC)

Thanks to all, so the answer will be "maybe", but it is ok 2003:F5:6F0B:F000:BC15:21C9:2807:BF90 (talk) 20:59, 1 May 2022 (UTC) Marco PB

High speed 2 contract values
In the UK’s High speed 2 packages, why is it that the station contracts (Euston and Old Oak Common) are about the same value as the civil packages? What makes the stations so expensive compared to the civils packages. The civils packages cover a wide area and include tunnels, bridges, earthworks etc whilst the stations only cover 1 site and is just an excavation and a building. Clover345 (talk) 16:09, 29 April 2022 (UTC)
 * Looking at This, Euston station looks to be a massive undertaking. It's not just a renovation of the existing Euston railway station, it appears to be rebuilding it from the "ground up", and rather ambitious.  In our prior discussion, we had said that stations did not necessarily need to be complex affairs, but the complete redevelopment of a 60-acre site in central London is a massive undertaking, and the costs you are seeing is likely commensurate with any similarly-sized project in that type of location.  -- Jayron 32 16:36, 29 April 2022 (UTC)
 * Would you say the same about Old Oak Common which has a similar value? ? What’s more interesting is that the terminus in Birmingham is less than half the cost. Clover345 (talk) 16:40, 29 April 2022 (UTC)
 * I'm not familiar with Old Oak Common, but the major difference between the Birmingham terminus and Euston is that the Birmingham station is being built mostly on the empty site of a previous railway terminus, whereas Euston is being rebuilt whilst having to continue all its existing railway and retail operations. Shantavira|feed me 19:02, 29 April 2022 (UTC)


 * Old Oak Common station will be entirely new. Quoting the article Old Oak Common railway station: "When built, it is expected to be one of the largest rail hubs in London, at about 1⁄2 mile (0.80 km) in length and 65 ft (20 m) below surface level." Also: "To overcome the site's limited access along the single-carriageway Old Oak Common Lane, and reduce lorry movements across London, a 1 km (0.62 miles)-long conveyor belt will be assembled to transport the excavated material to Willesden Euro Terminal railhead, to be removed by rail freight and then recycled." Does not sound like a minor construction job. --Lambiam 19:08, 29 April 2022 (UTC)


 * Old Oak Common railway station will be a "super-hub station" with "a total of 14 platforms... 44 escalators and 52 lifts" and it is "estimated that the station will serve 250,000 passengers per day".
 * It will be "the largest railway station ever built in a single stage" in the UK.
 * "Construction will be taking place in populated areas and disruption is anticipated for the duration of the project" Measures to mitigate this include the construction of a conveyor system to reduce heavy vehicle movements in the area. Alansplodge (talk) 19:34, 29 April 2022 (UTC)
 * The people around Euston station are up in arms because there are now going to be fewer platforms.  That means that the spoil from the works, which was going to be removed unobtrusively by rail, will be removed by road instead.   Had this method been used at Old Oak Common, the link says, this would have involved half a million lorry journeys.   So in Euston, a heavily built-up area of central London, the effect is going to be dire. 2A00:23C5:CD94:AF00:3962:351:70CB:E68C (talk) 16:02, 30 April 2022 (UTC)