Wikipedia:Reference desk/Archives/Science/2018 March 31

= March 31 =

Painkillers
Why hasn't science invented a non narcotic super tylenol for severe pain? It seems weird that we are still having to use drugs like morphine for severe pain that we used thousands of years ago and have nothing better to use that is non narcotic.--User777123 (talk) 05:52, 31 March 2018 (UTC)
 * The article says that Morphine was first isolated in the early 1800s. ←Baseball Bugs What's up, Doc? carrots→ 10:37, 31 March 2018 (UTC)
 * True, but that doesn't directly answer the question. 86.169.57.223 (talk) 11:12, 31 March 2018 (UTC)
 * Crude opium has been used for millennia; morphine is one of its constituents. It wasn't isolated until then. I suppose if you want to be extremely pedantic you can insist that people used opium, not pure morphine, but most people will understand what the poster was conveying. --47.146.60.177 (talk) 01:30, 1 April 2018 (UTC)
 * Drugs like Fentanyl still activate the μ-opioid receptors so are you counting that as a narcotic? See ATC code N02 and Category:Analgesics. Ziconotide treats serious pain also. Graeme Bartlett (talk) 12:27, 31 March 2018 (UTC)


 * It's a very challenging problem from a scientific point of view. It is very easy to treat pain if you allow numbness and paralysis. To treat pain without creating those undesirable effects requires finding drugs that affect the parts of the nervous system involved in pain differently from the parts involved in other functions. That isn't easy. Looie496 (talk) 13:59, 31 March 2018 (UTC)
 * In theory, pain can be blocked by any of
 * blocking the nociceptors (pain receptors). However, they also detect other things.
 * blocking the nerves. Doing so without causing paralysis is tricky.
 * blocking the brain for processing the pain. Doing so without doing so without damping the entire brain is hard. However, drugs like ketamine, which is a dissociative and also blocks the formation of memories, are useful.
 * LongHairedFop (talk) 19:49, 31 March 2018 (UTC)
 * In general, the answer to, "Why don't we have a drug that does X" is, "Because no one has developed one". As to why that is, our understanding of the body, especially the brain, is far from complete. It's relevant that you mentioned APAP, because we're still not sure how exactly that works. From an evolutionary biology perspective, pain is an incredibly ancient stimulus that is extremely selected for, because it helps an organism avoid or respond to things that are harmful: witness people with congenital insensitivity to pain, who are prone to serious self-injury. Given the importance of pain, it's not surprising it's hard to shut it off. Opium's analgesic properties were presumably discovered accidentally by ancient humans consuming the plant. The reason the opium poppy produces opioids is to stop animals from eating it. So funnily enough, our most potent painkillers originated from plants trying to poison us. --47.146.60.177 (talk) 09:11, 2 April 2018 (UTC)

Measurements of energy
US electric companies typically bill residential customers by kilowatt-hours. Why is this figure normal, rather than horsepower-hours (which are non-metric, as the US tends to be) or some multiple of joules? I just don't understand why one would express such a figure in a combination of units when a unit of this sort exists; it's like measuring pressure in "newton-squaremetres" instead of using pascals. No information at kilowatt hour, which only mentions joules in a comment on conversion. Nyttend (talk) 14:09, 31 March 2018 (UTC)
 * Why not bill in kilowatt hours? It has been the established unit for over a century. It is the unit most familiar to the customer - at least some of them have a workable understanding of load in watts or kilowatts, and the idea of multiplying that by the time of use. See the history of electricity meter, although that article's largely inaccurate.
 * The first billing was for "rated circuits", where a customer agreed the number of circuits (mostly lighting) and paid a flat rate per lamp. This is still used today for streetlighting! However the flexibility of electrical devices meant that once the portable appliance was invented, the load became unpredictable and so real metering was needed. Again, this began on the idea of assuming a rating and using a simple clock device to count the time of use (these lasted quite a while for some lighting applications, especially for local councils and the like). DC meters went through a phase of using electrolytic meters which measured current integrated over time, as they were the only practical integrators. These were calibrated and billed in ampere-hours, assuming a constant voltage, but of course the costs were driven by the energy (their product with the voltage) and multi-voltage supplies would be metered and billed at different rates for each.
 * AC changed things. Electrolytic meters were out and the voltage started to be sufficiently unpredictable that ampere-hours just weren't acceptable. There was at least one UK court case on the basis of medieval laws against selling "short measure" when the customer realised that their appliance (a bread oven, AFAIR) didn't work properly if the voltage was low. It was now necessary to have a proper watt-hour meter, measuring the product of current and voltage, and integrating this over time. Note that reactance and power factor was not an issue as yet (1880) as there were simply so few reactive motor loads in use as yet. Electric trams were still DC and generally generating their own power. Aron developed his differential clock mechanism (and watt-hours as a billing measurement) around 1883 and it went into commercial use from 1888. Spurred by this new development, the Hungarians (always near the front on AC development) produced the induction motor watt-hour meter which became the vastly predominant type until the last few years.
 * Now we have "smart" meters, which bill at varying rates in half hour slots through the day, are self-reading by radio and allow (commercial supplies at least) to be billed by algorithms so complicated in terms of correction factors for the presumed cost of supply that no-one understands them. Their billing systems are also now phenomenally inaccurate, such that large consumers have their own bill-checking departments to check their charges, and can (literally) save millions over a year by doing so. Andy Dingley (talk) 16:11, 31 March 2018 (UTC)
 * Electric power consumed by devices in the US is universally reported on the device in watts or kilowatts. Thus it makes sense for energy usage to be standardized to power times time used.  Horsepower is used in the US for mechanical power, not electric power.-- Jayron 32 16:14, 31 March 2018 (UTC)
 * Power isn't consumed here, energy is. [sic] So why base it on what's most apparently a measurement of power? It's a reasonable question. Why aren't we billed in Joules, or (as we are for gas) Therms, units directly of energy? Andy Dingley (talk) 19:08, 31 March 2018 (UTC)
 * You are billed for the power a device needs to operate times the time the device is on. That's how the unit was standardized.  If you do the dimensional analysis; it's a unit of energy as well, but for a customer, to estimate and check one's bill, you multiple the power rating of the device and multiply it by the time it is in use.  -- Jayron 32 12:30, 2 April 2018 (UTC)
 * 1 kW hr is 3.6MJ. However, as Hermann said, most folks can understand that a 1 kilowatt electric fire, left on for 1 hour, will use 1 kW hr of electricity. Or, a 100 W bulb left on for 10 hours will also use 1 kW hr. I doubt most folks will have an intrinsic understanding of 1 Joule (1 Watt-second). LongHairedFop (talk) 19:42, 31 March 2018 (UTC)
 * Hotel electric power - the confusing name for the electricity used by the passengers of a large ship or a train - is commonly measured in horsepower, because power is commonly provided by the same powerplant that also delivers mechanical propulsion; even if there is separate powerplant, it is still convenient to compare relative power in identical units.
 * For example, the CalTrain uses a MP54AC on many of its services: its tractive engine power output is decreased by 800 hp when under a nominal HEP load. That's a lot of power for running the air conditioning and lights!  As you can see in the brochure, it is also possible to convert and report the electric power in watts.  And, unlike residential electric utility service, the benchmark measured quantity is power, not total energy.  At the end of the day, the total energy is easy to measure: when the vehicle is refueled, you know exactly how to price the integral of power with respect to time!   Nimur (talk) 06:48, 1 April 2018 (UTC)