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January 6

Gears in gym equipment

The most common weight lifting machines around me just consist of a set of metal plates (can be configured) attached to a cable that go through two pulleys. I know that alternative ways of creating resistance for exercising exist, like pneumatic, elastics, and so on. I suppose these are not as resilient and low on maintenance as a simple block of metal plates with a cable attached. I wonder, couldn't they just make a machine with one weight and a set of gears to add more resistance? I imagine you could also use a level to alter the resistance, but that seem more of clumsy solution. --31.4.128.9 (talk) 08:20, 6 January 2020 (UTC)[reply]

They could, but a possible downside is that people like to know how much weight they are lifting, and the usual arrangement makes that obvious. Alansplodge (talk) 13:59, 6 January 2020 (UTC)[reply]

What's "resistance"? Are you after a large force on a small movement, or a lower force over a long distance? Weights have several advantages: they're simple, reliable and cheap. They also provide a high force, and they provide a constant force. Most spring devices will change force over their travel. It's also easy (with a pin in a stack) to change the force from the same machine, keeping the same overall distance. It's also easy to assemble a weight-based machine, whilst a spring machine might need an assembly jig and carry a risk of finger injury.

For high force devices, most use weights. Some use the operator's own weight - a common design for outdoor park exercise machines is based on lifting the user's own weight, which is usefully self-calibrating for a wide range of users, without needing to adjust anything. These tend to use levers as force adjusters, as the most long-term reliable machine. A few machines use springs or hydraulics, but these are more complicated and have maintenance issues. Elastic (i.e. polymer elastomers) is rarely used (small home-use devices), as it has lifetime issues and a sudden snap is a real problem to design for in a "safe" machine.

For higher forces, a pulley system is more common than gears. It stands up better to wear and exercise equipment is in a very litigious market, where reliability is important. There's sometimes a need to offer a longer movement (some horizontal pulls) and pulleys can do that too - otherwise it's easier to just make more weight go up higher.

For aerobic exercise rather than strength, the load was usually an air fan, a viscous drag or a magnetic eddy current in an aluminium disc. Nowadays though, machines are computer controlled, so active electrical devices (motors) are used, even though they're expensive, complicated and need a power source, just because they're more easily controlled. Andy Dingley (talk) 14:51, 6 January 2020 (UTC)[reply]

A convict in Victorian Britain might find exercise machines crank and treadmill provided for his benefit. DroneB (talk) 16:25, 6 January 2020 (UTC)[reply]

Neither of those were 'exercise' machines. They (deliberately) weren't particularly hard labour, they were mostly boring. Where convicts did actual hard labour (and Dartmoor was one of the few UK prisons where this was the classically hard-working stone-breaking work) they had to be fed better, or else they starved and died. In the typical prisons, the work was tedious but not so energetic, and so the food costs were lower. Andy Dingley (talk) 16:42, 6 January 2020 (UTC)[reply]

Torture and Democracy by Darius Rejali (p. 301) says: 'Nineteenth-century British prisons and reformatories preferred exhaustion exercises. Guards required prisoners to perform shifts on various devices, notably the treadmill (1817) and the crank (1840). As one ascended the wheel, the previous step slid away. It exhausted the strongest of men in fifteen minutes. Turning the crank required turning a handle twenty revolutions a minute, for a total often thousand revolutions in 8.5 hours. “No human being, whether adult or juvenile, could continue to perform such an amount of labour of this kind for several consecutive days, especially on a prison diet, without suffering much and wasting greatly".'

The quote is from Report of the Commissioners Appointed to Inquire Into the Condition and Treatment of the Prisoners Confined in Birmingham Borough Prison, and the Conduct, Management, and Discipline of the Said Prison (1854) p. vii. Alansplodge (talk) 18:02, 6 January 2020 (UTC)[reply]

"Victorian" goes on a long while after that though, and these were falling from use. I think the crank stayed for a long time, but it was specifically punitive (they still have one in Lincoln Castle). Andy Dingley (talk) 18:13, 6 January 2020 (UTC)[reply]

We have both a section of a treadmill, and a crank, in Ripon Prison and Police Museum. --ColinFine (talk) 19:10, 7 January 2020 (UTC)[reply]

Other sources of resistance are flywheels and generators. The latter have the advantage of offering a "reward" such as powering an electric fan. NonmalignedNations (talk) 06:22, 8 January 2020 (UTC)[reply]

Thought experiment: Star with mass in the Brown dwarf mass range with a lot of fissionable elements

Could a brown dwarf with enough Uranium or Potassium 40 shine above its weight class? Perhaps it could do normal hydrogen fusion, instead of deuterium fusion?144.35.45.50 (talk) 23:29, 6 January 2020 (UTC)[reply]

If it performed hydrogen fusion, it would by (current) definition not be a brown dwarf, but a low-mass red dwarf. The two catagories are not strictly segregated by mass (or any other single criterion), and may overlap in characteristics depending which one(s) one chooses to apply. {The poster formerly known as 87.81.230.195} 90.204.182.54 (talk) 23:55, 6 January 2020 (UTC)[reply]

Right, but beyond the question of classification, could such a star exist?Thanks. Rich (talk) 00:43, 7 January 2020 (UTC)[reply]

A natural nuclear reactor could easily exist if the concentration of uranium was high. Of course this is unlikely in a uniformly mixed gaseous body. Perhaps a star formed from binary neutron star merger hypernova output could be highly radioactive and hot, also containing plutonium and thorium. A lot of potassium would also make the body hot. Graeme Bartlett (talk) 03:06, 7 January 2020 (UTC)[reply]

Do you think it would require a fission chain reaction, rather than just many isolated fissions? The fissions here on earth produce a lot of heat.Rich (talk) 04:40, 7 January 2020 (UTC)[reply]

To explain what I meant, suppose a brown dwarf had a mass of 50 Jupiters, and for some bizarre reason, maybe advanced alien tech, that one of those 50 jupiter masses was entirely Pottasium 40. Then isolated disentegrations should provide much much more than just the heat of 32 Earths, because although jupiter is a mass of around 32 earths, fissionable atoms are a small fraction of theearths mass.Rich (talk) 04:51, 7 January 2020 (UTC)[reply]

This could actually make the star a more massive brown dwarf, possibly over the "typical" mass limit for a brown dwarf. A main sequence star is a ball of stuff in hydrostatic equilibrium; its gravity constantly tries to collapse it more, while the fusion in the core generates heat and tries to expand the star, and these two forces maintain a constant tug-of-war as long as there's sufficient fuel in the core. If there's another source of heat, this expands the star as well, opposing the gravitational collapse and therefore reducing the temperature and pressure in the core, possibly below that necessary for the p–p chain. --47.146.63.87 (talk) 07:47, 7 January 2020 (UTC)[reply]

Interesting!Rich (talk) 20:53, 7 January 2020 (UTC)[reply]

(edit conflict) Weight is not really a thing when talking about stars; scientists talk about them in terms of mass, which doesn't vary based on gravitational effects. If a star has enough mass to start the proton–proton chain, it's a red dwarf by definition, as noted above. A star with high metallicity will be denser than a low-metallicity star of the same mass, because the "metals" are denser and thus pack more mass into a smaller volume. This is an example of human intuition short-circuiting. We intuitively think of weight and mass as the same thing, because we think about things in our everyday existence under the influence of Earth's gravity. But stars are ginormous things that gravitate under their own gravitational fields. The primary thing that determines a star's character is its mass, because its mass is what produces its gravitational field. --47.146.63.87 (talk) 04:59, 7 January 2020 (UTC)[reply]

I don’t think any of the posters, including myself, have in any way confused mass with weight. You’ve misunderstood what’s been said.Rich (talk) 07:07, 7 January 2020 (UTC)[reply]

The OP, who 47 replied to did in fact use "weight class" in the question and "mass range" in the heading. I don't know if the OP is actually confused about the difference between weight and mass, but although the term weight is often used to refer to mass in a colloquial sense, I'd agree with 47 that this is one case where it important to appreciate the difference. Nil Einne (talk) 14:38, 7 January 2020 (UTC)[reply]

This is my bad, im the OP. I forgot i used that idiom/sports cliche. “Punching(or shining or performing) out of one’s weight class often does not, now, refer to weight and boxing anymore, for example if a usually poor student outstudies and outscores the class brain on an exam, or if a slow sprinter gets a fast time on the 400 meters due to high anaerobic endurance, it’s said they are performing out of their weight class.Rich (talk) 20:51, 7 January 2020 (UTC)[reply]

January 7

relation of human-fungi for antibiotics

In biology, we have many types of relations between two organisms and more (i.g. commensalism, symbiosis etc.). My question is what's called the relation / way of people to take or produce antibiotics by fungi? 93.126.116.89 (talk) 00:11, 7 January 2020 (UTC)[reply]

It is called Medicinal fungi and Wikipedia has an article about it. --Jayron 32 12:07, 7 January 2020 (UTC)[reply]

Thank you for your comment, but it isn't my question:). I asked about the relation (I gave a couple of examples for relations in biology: commensalism, symbiosis). 93.126.116.89 (talk) 21:17, 7 January 2020 (UTC)[reply]

Typically the fungus is destroyed in the process of consuming it. You would call it mycophagy. A non-human animal that consumes another organism for medicinal purpose could be said to be engaging in zoopharmacognosy. Someguy1221 (talk) 21:57, 7 January 2020 (UTC)[reply]

Why we can't call it Amensalism? see here for example. 93.126.116.89 (talk) 21:21, 8 January 2020 (UTC)[reply]

If a person or other animal is gaining a health benefit from the interaction, it's not amenalism, which is neutral to one party and detrimental to the other. Someguy1221 (talk) 01:52, 9 January 2020 (UTC)[reply]

January 8

Which of "geometric algebra" or "algebraic geometry" proceeds the other.

Wow! sushi (talk) 05:08, 8 January 2020 (UTC)[reply]

(we don't have so much time...) _ I need to confess , I am multi-personalities.

Wow! sushi (talk) 05:12, 8 January 2020 (UTC)[reply]

Geometric algebra#History 1844

Algebraic geometry#History 16th Century? Graeme Bartlett (talk) 05:50, 8 January 2020 (UTC)[reply]

Insect identification

Hello, What is this insect called? I found it in Mizoram, India. There are shells on the body and the trail illuminates in the dark.

Sandeshkumar M. 11:19, 8 January 2020 (UTC)

Are you sure this is an insect? Check the underside for number of legs. It has the same number of segments as a woodlouse. Graeme Bartlett (talk) 09:50, 8 January 2020 (UTC)[reply]

I don't really know what it is. An insect or something else. I've uploaded another image of the creature.

Sandeshkumar M. 11:28, 8 January 2020 (UTC) (talk)

To help accurate identification include -

Something to show scale: ideally that would be a ruler with millimetre graduations. A picture of the bottom of the organism. A white background for the picture - it helps to give a better idea of the colour of the organism. A picture of the bioluminescence - this would be in an ideal world. A picture of the place you found it - to give an idea of habitat. A general name like Mizoram is useful - it narrows things down. But was it in woodland or human settlement. I appreciate this is a lot of information, but accurate identification is aided by this kind of information. There are places in India where bioluminescence is common. For Mizoram, that seems to be plant based rather than animal so more information about the animal is really needed to identify it correctly.

Having said that: it does look quite like a woodlice (and definitely an isopod). But I only counted eleven obvious segments - there could be 14 which is indicative of a woodlouse - a picture of the rear end from above would help to clarify that. There appear to only be three pairs of legs - woodlouse have seven pairs of legs (they can vary in size, so only seeing three pairs might mean the others are hidden). — Preceding unsigned comment added by Hongnang (talk • contribs) 12:55, 8 January 2020 (UTC)[reply]

Isopod link. NonmalignedNations (talk) 16:42, 8 January 2020 (UTC)[reply]

This might actually be a firefly larva. Graeme Bartlett (talk) 00:06, 9 January 2020 (UTC)[reply]

Yes I also think this is a bioluminescent beatle larva. Just as it is said that there are 11 segments on its back and and the last two segments have white patches which illuminates in dark.

And thanks for all your help. But don't know which species.

Sandeshkumar M. 02:14, 9 January 2020 (UTC)

Human Predation

When a predator is removed from the food chain it is often seen that there is an overpopulation of another species. The most well-known example I can think of at present (which is not the same) is the Cane Toad in Australia, where without a predator, they have bread to enormous population sizes causing widespread destruction. Further to this, if predation on a species takes place the food item tends to populate to make up for the loss and similarly if a food source reduces the number of predators reduces too. To expand on this concept, if my reserve has 10,000 impala and I have 100 lions, (10:10,000)… if the lions eat 2,000 impala, the impala will generally have about 2,000 offspring during the next breading cycle, and the numbers (presuming they are evenly matched, lions to impala and assuming there are no other animals [work with me here people]) In the same manner, if I hunt 9,000 of my impala, my lions will die off until I have only 10 (1,000:10). Nature ensures there is an equilibrium, if all of the additional environmental factors are left in situ and allowed to run their course. What has been removed from the ecological chain to allow for the human race to overpopulate to such a degree as to cause the now seen climatic chaos. How was this element removed? Thanks. Anton 81.131.40.58 (talk) 15:56, 8 January 2020 (UTC)[reply]

Are you looking for a book on basic ecology? Humans fill a niche in the local and the global ecosystems, but your description of simplified replacement of one species by another... well, that is just overly simplified. Start with our Wikipedia article on ecological niche, human evolution, and so on... Nimur (talk) 16:15, 8 January 2020 (UTC)[reply]

Technology has allowed humans to expand from one ecological niche to many others. Chimpanzees, by comparison, only inhabit small portions of Africa. One very simple technology humans use is clothing, allowing us to live in far different climates, such as the arctic. And predation doesn't limit human numbers, since humans are more likely to kill the predators, such as sharks or lions. NonmalignedNations (talk) 16:37, 8 January 2020 (UTC)[reply]

Where’s Greta when you need her?

Linked to the previous question and brought to my attention recently by a much younger person, was that the current environmental crisis should resolve itself. The rationale provided for this argument was that all of the fossil fuels and Co2 gasses being put into the atmosphere are all from earth and have been part of the ecology and part of the overall cycle of minerals etc. within the planetary system. I was not able to counter this point, as my questions clearly show I am not a scientist or scientifically minded. Please would you help me to understand why this theory does not hold water, as I am sure that it doesn’t but can’t explain why. Thanks. Anton 81.131.40.58 (talk) 15:57, 8 January 2020 (UTC)[reply]

Review the Wikipedia article entitled tipping points in the climate system, which is written for a general audience but cites detailed technical sources for the interested reader.

Some complicated systems are self-stabilizing; some are subject to instability. Scientists have reason to believe that some aspects of the Earth's climate may be undergoing an irreversible alteration that deviates from the stable "self-regulating" zone, which is one of the reasons for international concern. If you're interested in why some scientists believe such things, our article is a great introduction to the science, data, and models, that drive their concern. Nimur (talk) 16:08, 8 January 2020 (UTC)[reply]

As for burning fossil fuels, those are burnt far faster than they accumulated, meaning we have millions of years worth of fossil fuel produced gases all in the air at once. This leads to much higher concentrations of greenhouse gases than would naturally occur, and hence more greenhouse effect, and unnaturally higher tempertures. NonmalignedNations (talk) 16:54, 8 January 2020 (UTC)[reply]

Maybe we should all go back to using wood-burning stoves. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:59, 8 January 2020 (UTC)[reply]

Actually, pellet stoves, which burn compressed wood pellets, are looked at as a renewable heat source that is much closer to "carbon neutral." But in response to the OP, NN has the obvious and correct answer that's easier to explain than tipping points and the complications of these systems. Yes, all of this CO2 was once in the atmosphere, but not all at the same time. Even if we were to assume that all of the coal we have burned (or will burn) is from just the Pennsylvanian subperiod (a lot of the coal is from that time, but not all of it), and we take the period of industrial output to be from 1760 (the start of the Industrial Revolution, and this is generous since our output has accelerated over this time period a lot), that means we have been outputing CO2 that took nature about 24 million years to sequester in the space of 260 years. In otherwords, we are releasing CO2 into the atmosphere about 90,000 times faster than nature took it out of the atmosphere. Again, these are really rough numbers and I could be off by an order of magnitude or so, but you get the general idea. That's also just for coal, it doesn't account for oil at all. --OuroborosCobra (talk) 19:07, 8 January 2020 (UTC)[reply]

There is an obvious response to this if you understand the history of the Earth. Earth was once a ball of molten rock, so if it becomes that again, there's no problem; it'll all sort itself out. Earth was once hit by an asteroid 10 miles in diameter, so if that happens again, there's no problem; it'll all sort itself out. Earth is a big ball of rock. It's not going anywhere. The problem is we're disrupting our biosphere, which we rely on for things like food. Also, heat plus humidity means in some places it can get too hot during the day for humans to survive outdoors. Earth will "sort itself out" just fine; it's just that this might involve lots of humans dying. Or in the words of the late great George Carlin: "The planet is fine. The people are fucked!" --47.146.63.87 (talk) 22:05, 8 January 2020 (UTC)[reply]

Nature always wins. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:08, 9 January 2020 (UTC)[reply]

Help me identify raptor

The raptor above was photographed by me today, from the window of my office on the 26th floor of an office building in downtown, Brooklyn, NY. By no means is this his or her first visit; this raptor swings by approximately weekly recently, and he has been coming to my ledge at various times for a few years. I was wondering if someone with some expertise can definitively identify the species (hopefully my picture is clear enough for that). I think it's a peregrine falcon but I am far from certain in my lay identification. Thanks--Andy-Em-Ess (talk) 18:47, 8 January 2020 (UTC)[reply]

It appears to be a Peregrine falcon. When in doubt, I consult the Peterson Field Guides appropriate to my region. Those books have comparison pictures and point to the exact most distinctive markings that help disambiguate and distinguish one bird from another. Nimur (talk) 20:49, 8 January 2020 (UTC)[reply]

This report looks at Peregrines in New York. Given where you saw the bird, and the Peregrine's love of high vantage points for hunting, that identification seems almost certain. Mikenorton (talk) 09:27, 9 January 2020 (UTC)[reply]

Does it have a name? May I Suggest Mr Chubby-cheeks? Thanks. Anton 81.131.40.58 (talk) 15:39, 9 January 2020 (UTC)[reply]

January 9

@@ Line 124: / Line 124: @@
 :It appears to be a [[Peregrine falcon]].  When in doubt, I consult the [[Peterson Field Guides]] appropriate to my region.  Those books have comparison pictures and point to the exact most distinctive markings that help disambiguate and distinguish one bird from another.  [[User:Nimur|Nimur]] ([[User talk:Nimur|talk]]) 20:49, 8 January 2020 (UTC)
 :[https://www.amny.com/news/peregrine-falcon-nyc-1-36858953/ This report] looks at Peregrines in New York. Given where you saw the bird, and the Peregrine's love of high vantage points for hunting, that identification seems almost certain. [[User:Mikenorton|Mikenorton]] ([[User talk:Mikenorton|talk]]) 09:27, 9 January 2020 (UTC)
+Does it have a name?  May I Suggest Mr Chubby-cheeks?  Thanks.  Anton [[Special:Contributions/81.131.40.58|81.131.40.58]] ([[User talk:81.131.40.58|talk]]) 15:39, 9 January 2020 (UTC)
 = January 9 =