The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.
Can someone explain this in simpler terms? Am I right in assuming that if Lorentz symmetry is broken, things can/do have an absolute velocity, position, orientation etc.? What is "dynamical" symmetry breaking? 93.139.41.72 (talk) 02:23, 10 September 2017 (UTC)[reply]
It means that if there existed some background static and spatially homogeneous vector or tensor field, it would be possible to measure absolute velocity and orientation relative to it. Such a field can appear as a result of some interaction within an initially Lorentz invariant theory - dynamically. So, Lorentz violation is fictional because the theory remains Lorentz invariant. For instance, if you are inside a large volume and there is a constant and homogeneous magnetic field inside it created by currents at the large distance from the observer, one may (without any information about what happens at large distances) conduct some experiments and conclude that there is indeed a preferable direction. Ruslik_Zero18:34, 10 September 2017 (UTC)[reply]
If the tech level/population/GDP/Milankovitch factors/Sun/biosphere etc. stopped evolving in 1749 how long would it take for CO2 to rise 1ppm?
Would the anthropogenic fire/cow flatulence etc. carbon just go in the carbon sinks and the CO2 ppm in the atmosphere would never rise? Would this cause any ocean pH changes measurable with 2017 instruments? (our 2017, they're still using horses and buggies in this timeline's 2017 remember) Sagittarian Milky Way (talk) 03:08, 10 September 2017 (UTC)[reply]
Too many variables, I think. Civilizations at that tech level tended to grow in population until the available land was all under cultivation. Examples include Italy, Greece, India, China, and England. If we project forward from 1749, humanity would have cleared the forests everywhere by now (except possibly for parts of Africa which are protected by diseases). The effect on CO2 levels is hard to analyze. Also that tech level still allow for coal mining, which would be economically attractive as the forests disappeared. This was already happening in England by then.-Arch dude (talk) 04:52, 10 September 2017 (UTC)[reply]
The Black Death in Eurasia followed by the huge mass deaths in South and then North America from smallpox and other diseases are thought to have been one of the major contributors to the beginning of the Little Ice Age because they caused CO2 to drop due to reforestation. The reforestation would be pretty rapid but the effect on temperature would be much slower, there would be a drop in CO2 and then it would rise to near its former level as in 1400 over a couple of hundred years. So yes I believe in 1749 you'd be looking at CO2 rising again so I guess they should only have taken about twenty years to rise 1ppm at that time. I'd say 1749 was about the beginning of the modern world so yes you are cutting out a lot of stuff never mind other factors that contributed to the Little Ice Age. One would really need a climate scientist to model it to get something reasonable but there are a lot of unknowns. Dmcq (talk) 11:48, 10 September 2017 (UTC)[reply]
Not an answer to your question, but memorably Svante Arrhenius estimated around the year 1900 that it would take about 3000 years to increase CO2 concentrations by 50%. Of course, we found many new uses of fossil fuels since 1900. Dragons flight (talk) 19:27, 10 September 2017 (UTC)[reply]
He probably did not think of all the important forcings (probably we don't even know all, depending on how you define "important" and at what time frames you are looking), but yes, he did include water vapour feedback and ice/albedo feedback (of course limited by the computational resources of the day), and his result is essentially still squarely near the middle of modern estimates. --Stephan Schulz (talk) 07:31, 12 September 2017 (UTC)[reply]
Not really, he was off be a factor of 2 from the present-day preferred value. That's close, and quite good for his time, but it is probably a stretch to say he is in the middle. Dragons flight (talk) 08:31, 12 September 2017 (UTC)[reply]
Yes, you are right - I misremembered his result as 3° when it was 5-6°C, which is still not implausible, but at the upper limit of current estimates. Sorry. --Stephan Schulz (talk) 08:47, 12 September 2017 (UTC)[reply]
According to File:Measles vaccination coverage world.svg (data from 2010), Austria's vaccination rate was lower than that of countries like Chad, Iraq, and the Democratic Republic of the Congo. Why is their rate so low?
According to the german wiki:
In Österreich werden zwei Teilimpfungen gegen Masern-Mumps-Röteln ab dem vollendeten 9. Lebensmonat mit einem Mindestabstand von vier Wochen empfohlen. Bei Schuleintritt bzw. mit vollendetem 12. Lebensjahr soll der Impfstatus (Impfpass) kontrolliert werden. Fehlende Impfungen können in jedem Lebensalter kostenlos nachgeholt werden.[73] Eine Erhebung des Gesundheitsministeriums aus 2016 ergab, dass über 95 Prozent der 6-jährigen Kinder zumindest einmal gegen Masern geimpft sind. Bei den 2- bis 5-jährigen Kindern beträgt die Durchimpfungsrate jedoch nur 92 Prozent, zudem sind etwa 10 Prozent davon nur einfach anstatt zweimal geimpft.[74]☂[75]
Of the 6 year olds, 95% have received the vaccine at least once, according to 2016 data. Of the 2 to 5 year olds, 92% have received the vaccine at least once, 82% twice. It doesn't seem as dramatic as the map suggests. Maybe confusion over the exact meaning of vaccination (once or twice) or the age at which vaccination rate is measured. PiusImpavidus (talk) 09:45, 10 September 2017 (UTC)[reply]
[1] from 2015 using data from the WHO from an unknown period suggests Austria is "At a 75 percent immunization rate, Austria comes in just above Afghanistan, but below even Yemen and Sierra Leone." [2] suggests a big issue for Austria is the number of unvaccinated older adults. Those who never caught the disease and were never vaccinated. Although it also mentions the general challenges vaccinating adults who were never vaccinated, which does highlight a point. Even if your vaccination rates are now fairly high (albeit 95% actually doesn't sound that high to me even if it's significantly higher than the other figures) for children, if it was low for whatever reason for a while it's only going to slowly increase unless you're able to vaccinate unvaccinated adults. Otherwise you have to wait for them to die off or have such a high population growth that they are only a tiny percentage of your population. Nil Einne (talk) 18:17, 11 September 2017 (UTC)Clarified: 08:48, 12 September 2017 (UTC)[reply]
From [3] it sounds like measles is a small problem for them - 75 cases in 8.6 million people a year, in hotspots. The vaccine came out in the 1960s but there was not much retroactive vaccination of children who had already grown up and not caught it. Wnt (talk) 22:56, 12 September 2017 (UTC)[reply]
Chicken pox
According to [4], approximately 1% of individuals vaccinated with chicken pox will develop symptoms similar to that of an ordinary low-grade infection, and it's possible for them to develop shingles late in life. Have any cases of shingles been observed in those who were vaccinated without developing symptoms of a chicken pox infection? I'm not clear whether it's possible just in those who develop symptoms or in all those who are vaccinated.
Varicella vaccine gives some information. I'm pretty sure it's possible, because the varicella vaccine is a live vaccine. You're being deliberately infected, just with a weakened strain of the virus, and varicella, once acquired, hangs around for life in your cells (as do all of its family, the herpesviruses), and its reactivation is what causes shingles. If anything, I'd think people who have a reaction should be less likely to develop shingles, because it means their immune systems were more strongly activated by the vaccine. --47.138.161.183 (talk) 05:52, 10 September 2017 (UTC)[reply]
Going to have to disagree a 'little bit' with Ruslik_Zero . The immune system is complex. Chickenpox like measles is reasonably contagious but the primary immune system (for want of a better phase) in some individuals prevents the virus from even getting hold and invoking an infection where the virus can turn the hosts body cells in to virus factories. In those individuals the virus can't lay dormant, for it to develop latter into singles. Please Note: The jury is still out. Yet, it appears that if an individual does not contract chickenpox naturally nor show a reaction to the inoculation then they do not go on to develop shingles. Another observation is that regardless of whether chickenpox infection was acquired naturally or by immunization – it doesn’t provide life long protection in those without natural resistance. So, the reason why singles is now becoming so much more common in older people is being put down to the fact that they are no longer having their immune system boosted naturally by coming into contact with children that have a full blown chickenpox infections who are shredding off billions of viruses. Thus requiring old inocululyees to require booster shot latter in life. It appears that if as a child, the individual showed no reaction then there is no proven epidemiological reason that a MD should insist on a booster – other than for financial reasons. Aspro (talk) 14:32, 11 September 2017 (UTC)[reply]
I am not sure where these ideas come from? I am not aware of any such publications. You have probably failed to read the paper that I linked to above. There is no such thing as natural immunity to HHV3. Any individual that comes into contact with the virus will be infected and the virus will establish its presence in the dorsal root ganglia. In many individual this primary infection can be overt (in the form of chickenpox) but in some it is silent. However any infected individual can later develop herpes zoster. If you had read that paper, you would have found that even among immunized 1/3 of cases of herpes zoster is due to the wild virus, not one from the vaccine. So, silent infections happen all the time. As to children serving as natural boosters to older persons, this no any agreement here. Infected individuals can self-boost their immunity and this self-boosting may be more important than any boosting from an external source. Ruslik_Zero18:45, 11 September 2017 (UTC)[reply]
Can see where your coming from. At school, we are taught that for an individual to have 'immunity' they need antibodies (acquired either by previous infections or through the placenta or via inoculations) to fight off a future infection. This is a gross over simplification of the immune system. For many decades now it has been known that interferon and interleukin I I and other immune responses can make an individual a non-viable host to some viruses. Interferon is species specific and if an individual has an interferon type to make that individual a non-viable host for said virus- then that virus can not invade the cells and take them over in order to replicate. Because the virus can't survive, replicate and cause an infection, the B-cells are not called upon to produce antibodies. Likewise, the afore said HHV3 virus can not survive in the dorsal root ganglia to later cause shingles. Thus, such an individual with an antibody titer of zero for chickenpox can be exposed multiple times to chickenpox and not get infected (nor pass it on). This sort of in-depth of understanding doesn’t have to be taught to doctors for the obvious reasons that they never have to treat these individual for those viral diseases for which they are naturally and genetically immune too. To underline 'non-viable' host with an extreme example. [Killer mousepox virus raises bioterror fears. Your antibody titer should be zero for this virus too. Yet, if you have understood the above, you will fear not (fingers-crossed). Aspro (talk) 13:29, 12 September 2017 (UTC)[reply]
You again failed to cite any source claiming that there are humans who are not susceptible to HHV3 infection. It is true that mice are not susceptible to HHV3 because viruses are often species specific but different humans belong to the same species. And your understanding of the human immune system is incomplete - B-cells and antibodies is just one its many branches. Ruslik_Zero08:52, 13 September 2017 (UTC)[reply]
This has had me searching for not science papers, because they only focus on a tiny bits and don't give an overall picture – which wont help you – unless you're prepared to do an awful lot of reading. Found this though: The Defending Army It is a pretty old book now, yet has 9 respected consultant editors (who papers appear on goggle scholar). It covers all of what I have been saying and is aimed towards giving the layperson an understanding of the wonders of our immune system -so is easy to follow. It also ends with few chapters on how the state of mind has been found to effect the immune system. Skipped through a few pages and it goes into details that your general physician wont have be taught about even today. Wish I had come across a book like this, forty years ago. So thanks for asking and getting me to search for sources of simple explanations.Aspro (talk) 16:00, 13 September 2017 (UTC)[reply]
Irma in Florida
I am wondering about the hurricanes. There is an article in Wikipedia that tries to explain it all.[5]. It seems the following it clear. The earth rotation linear velocities differences at different latitudes create cyclones. Had the earth been a cylinder no cyclones could have happened, right? Heat coming from the ocean is needed too. It is an enormous angular momentum after all. How come Irma hit Cuba, touched it a bit and turned North to Florida? Why? Where is the force that did it? Logically it would have to continue to the East coast of Mexico.
In the Atlantic the hurricanes travel West, in the Pacific they seem to travel East and in the Indian subcontinent they definitely travel East. Why?
Answering just the last question: see Great Red Spot. It has been seen since 1830, and is believed to be the same spot that was first observed over 350 years ago, but the record of observations is not continuous. It might be only about 190 years old, or it might be thousands of years old. --69.159.60.147 (talk) 21:23, 10 September 2017 (UTC)[reply]
Hurricane Irma's recurvature is largely due to forces exerted on the system by other areas of atmospheric pressure, particularly a high-pressure "ridge" over the North Atlantic known as the Bermuda High. See this Washington Post article for a summary.
Atlantic, Indian, and Pacific (and South Atlantic) tropical cyclones all predominantly travel westbound, not eastbound, though recurvature is not uncommon in all basins as systems move away from the equatorial trade winds, as per our article.
Jupiter's Great Red Spot is dated via continuous observation for ~190 years, and via inference from observations of a similar phenomenon (commonly assumed to be the same formation) dating back to 1665, as per our article. — Lomn21:24, 10 September 2017 (UTC)[reply]
How are the wires oriented in contactless card? It seems to me that no matter how I hold it, the reader manages to connect to it. Are the antenna and the RFID in the card coils? Are they multiple wires, oriented in multiple direction, to guarantee that one will get induced?--B8-tome (talk) 07:52, 11 September 2017 (UTC)[reply]
Doesn't much matter. The design and position of the antenna in the reader is such that it'll get it somehow. Provided that there is some field which the card's antenna intercepts, then it'll read. If you carefully align the card to be vertical (relative to the reader antenna) then you can stop it, but this is a very narrow null position - you need to be watching a signal strength meter to feel for it and even then you're unlikely to hold it in place accurately enough.
These cards (ISO/IEC 14443) are at quite a low frequency - 13.56MHz So they work by loop antennae, as a dipole antenna would be too big to carry. As the "card" needs to be flat enough to fit in a wallet, they're almost all a loop antenna around the edge of the card, to make it as big as they can.
It's possible to read these from huge distances away, if you have a big enough loop on the reader and ignore the official power limits - fraudsters are already doing this. If they have access to a venue for installation, or can do it surreptitiously, then any doorway or closed-loop archway you can walk through is potentially a place for a reader.
You can buy RF shields. Some of them work. You can of course test them with a standard reader in many honest shops. But tinfoil and optimism won't do it. Andy Dingley (talk) 12:52, 11 September 2017 (UTC)[reply]
A Faraday cage is a shield purely against an electrostatic field, rather than electromagnetic radiation. Particularly for frequencies this low, and with loop antennae (the size of which, relative to the wavelength, will influence the shape of this field) a Faraday cage makes a poor radio shield. Now of course you can say, "It's all just electromagnetism, so it's all the same" - which would be half right. Hopefully WP has a better article on RF shielding, because a Faraday cage is starting on the problem from the wrong end.
As to sources, then unfortunately I can't post the NFC and 14443 studies I have, as they're commercially confidential (and very expensive). The published books I have are all a bit old, so not covering this technology in specific detail. But it's core postgrad EE stuff and in all the usual books. 1980s sources (and in the UK is was the TEMPEST hoo-hah that set it off) start to look at issues of 1-100MHz shielding against close proximity devices.
As to making a shielded wallet, then forget tinfoil. Use copper tape instead, or else rigid metal sheet (the stuff stripped out of a scrap laptop is better than anything from a kitchen). But really, a carry-around shield ought to be made from properly made stainless mesh, woven as an RF shield (and not as an oil filter!). Expensive in middling quantities, but you only need a small piece and it's a pig to sew, so buy a good ready-made shield. If you do make a tinfoil shield, test it when new, then progressively as it ages from carrying around. Andy Dingley (talk) 15:08, 11 September 2017 (UTC)[reply]
Thanks. "But it's core postgrad EE stuff", sure, but I don't think I should need a MSc or PhD in EE to see why aluminum foil doesn't provide good RF shielding. The RF shielding article says "Copper is used for radio frequency (RF) shielding because it absorbs radio and magnetic waves.", but gives no further explanation. This is technically true of many metals, correct? It seems implied that copper is better than many alternatives, and that's fine, I don't mean to get in to the atomic structure of metals etc. However, I see plenty of reports online of e.g. cellphones wrapped in aluminum foil not ringing, cards wrapped in aluminum foil not reading at shops, etc. I grant that I have not done these tests personally, but in aggregate the do seem convincing, especially because what I know about Faraday cages. Now, the static vs/dynamic field is a good point, but it seems from first principles that time-varying fields will still be notably distorted when passing in/out of a Faraday cage. For practical protection of a credit card, it is not necessary to completely conceal a reflected ping, only to obscure the signal enough to prevent if from carrying all the same payment info (nb, I know this may require a fair amount of distortion, I'm sure the error detection/correction deployed in these technologies is quite advanced.
Perhaps what you're saying is more along the lines of "Casual application of aluminum foil is not a sufficiently general and robust method of RF shielding. Though it does have some effect on some signals/frequencies, I would not recommend it for serious (govt, engineering, security) applications."? SemanticMantis (talk) 15:46, 11 September 2017 (UTC) (PS: To be clear on the deleted cmoment, I know the phrase "tinfoil hat", and I was responding to you on matters of science, not Hofhof's joke comment, as per WP:THREAD. Also a good example of how jokes on the reference desk can impede communication and scientific discussion, even in small print.)[reply]
Cellphones and WiFi work at frequencies of a gigahertz or two. I'm old enough to believe that nothing cheap and plastic can possibly work at such frequencies and (like broadband over telephone wires) it must simply be demons instead. You can shield those with a thin layer of a conductive metal foil - even then though, it's not a Faraday cage in the simple electrostatic sense.
Card systems though are using a low frequency (13.56MHz), so their shielding needs to work differently. There is less difficulty in shielding tiny holes in an enclosure (WiFi goes through mouseholes), but it's much more difficult to find a bulk shielding material to make the "walls" of such an enclosure. Given the ability to make an antenna bigger than the "wallet" and unrestricted power, I cannot imagine any shield that you could fit in a pocket and that would still be guaranteed to shield it. It is a hard problem to make such a shield for such a frequency, against a large loop antenna.
Aluminium tinfoil is a problem though. Copper has better conductivity and aluminium has a surface oxide that stops it easily forming a single conductive wrapper. Also it's mechanically weak to fatigue and an aluminium foil carried in the pocket will simply fall apart quite quickly. If you want one, use stainless mesh, woven from a grade of stainless with adequate conductivity (hence no oil filters).
If you compare anti-theft electronic article surveillance, the 8.2MHz radio tag versions of this are possible to shield (shoplifters put them inside tinfoil bags, and the shop antennae are restricted in their interrogator power, a limit that card fraudsters don't follow). As a result, other systems are often favoured for high value stock, using magnetic systems rather than the 8.2MHz radio tags. Andy Dingley (talk) 16:16, 11 September 2017 (UTC)[reply]
DIY supercritical steam rocket
Would the following steam rocket design work? We take a thermos flask and fill it partially with hot oil (at about 600 C). We then put in boiling water in the flask using a plastic sheet so that the water initially does not make contact with the hot oil. We then close the thermos flask, turn it upside down at which point the water at 100 C will mix with the hot oil. The lid of the flask must be made such that it will break off at some high pressure that is well below the pressure at which the thermos flask would explode. Is there a simple DIY-way to construct a lid such that it will give way at the right pressure? Count Iblis (talk) 17:32, 11 September 2017 (UTC)[reply]
That's not a supercritical rocket. Instead it's a subcritical steam rocket, hoping to power itself by conduction from a mixture with heated oil.
There are several problems:
It's subcritical. Rather than being a supercritical rocket, where a slow process (heat transfer) is replaced by a fast one (vapourisation and expansion), it's stuck waiting for slow conduction from the mixed oil.
It relies on synchronising two things, mixing and releasing. This is why hypergolic rockets are easier [sic], they turn the two steps of propellant injection and ignition into just one, injection. Similarly a supercritical steam rocket needs to have its blowout disc blow open at some point, but it's less critical as to precisely when.
It assumes that the "plastic sheet" is also a thermal barrier.
It relies on the oil mixing with the water, such that heat conduction will be from small droplets with a great surface area. How does the oil get mixed or dispersed so quickly?
The reaction mass will be a mix of steam and liquid oil droplets, so probably not ideal for getting the most specific impulse from the heat energy.
Oh, and you don't need a Dewar or Thermos, maybe just a little bit of insulation. You have to heat this up, so you probably do that from outside anyway. Mostly you need a super-strong vessel, as the stronger it is, the higher the pressure you can use it at. This is why ex-WWII aircraft oxygen bottles (before the liquid oxygen systems, or the untestable composite pressure bottles) were used. If you're losing heat you can just add more, but a strength limit is a strength limit and Dewars are never very strong.Andy Dingley (talk) 18:04, 11 September 2017 (UTC)[reply]
The oil would all float above the water, so there wouldn't be much contact area. This would slow the heating of the water. But, it would work, to some degree. You could just use a thin material as the cap, or get a "pressure relief valve" if you need to control the temp better. Also, using a pressure cooker instead of a thermos might make sense, as modern ones have built-in pressure-relief valves. I'm skeptical that you could get it to launch, but you might get it to spin, provided the valve release if off-center, using an apparatus like Hero's engine. And beware that the hot oil spewing from the valve would pose an extreme burn hazard. StuRat (talk) 17:53, 11 September 2017 (UTC)[reply]
This maybe alright as a thought experiment but don't attempt to do it. Live steam is very dangerous and more (lethally) so, if you have to ask these sort of questions in the first place. Although, I do like the idea of mixing oil and water together – that would make a fireman’s day and the local funeral parlor very happy ! Hay, why stop at oil? Add some red fuming nitric acid the mix to archive criticality and maybe you'll be lucky enough to conflagrate your neighbor's home as well. Aspro (talk) 18:26, 11 September 2017 (UTC)[reply]
There is no "right pressure" that won't turn your rocket into a pipe bomb. You cannot hold the pressure of steam in a thermos, so any lid, no matter how weak, will work as well as any other lid. just put a square of heavy plastic like a zip lock freezer bag over the mouth and hold it in place with several rubber bands.
So you would either have to up the temperature of the oil by a factor of 2.5 or use 2.5 times more oil than water.
Your next problem is that the water will not stay in the thermos long enough to turn into steam. The first 1% of the water tuning into steam will blow the rest out of the opening (or blow up your pipe bomb if you use a really strong lid). --Guy Macon (talk) 18:43, 11 September 2017 (UTC)[reply]
It strikes me the main thing missing from this model is a nozzle, e.g. the de Laval nozzle mentioned in the steam rocket article. The science of rockets is a science of nozzles. In theory, hot oil could be used as a reservoir of heat, though producing the heat with a chemical reaction would seem like a lighter option. My assumption is you want to pump your water (even with a simple air pressure mechanism) into a small space ('engine') heated with hot oil or other means, then have it turn to steam near where it exits the nozzle and gives you decent thrust. The hot oil possibly ought to have some way to dribble out too so it can be replaced by fresh hot oil from a reservoir. Maybe you could have it with fuel injectors, only a nozzle replaces the piston? I'm not a rocket scientist, but come on guys, at least try. ;) Wnt (talk) 22:50, 11 September 2017 (UTC)[reply]
P.S. Should the temptation to light that oil get the better of you, there's some discussion about diesel rockets (or alternatives) here. The RP-1 article says OTRAG actually launched a diesel rocket, and of course kerosene is used ... honestly, I don't know what oil you had in mind anyway. Wnt (talk) 23:01, 11 September 2017 (UTC)[reply]
Funny noone stumbled over the plastic sheet at 600 C yet! The best "plastic" industry can offer today can endure up to 600°F aka ~315°C for short periods of time. Additionally and generally please always keep a save distance to anything "supercritical" and dont even think about messing with it unless you have a professional licence for exactly that. You shure dont want to wake up in hospital, blind and feeling your marmorized face from 3rd degree skin burns. --Kharon (talk) 05:34, 12 September 2017 (UTC)[reply]
Hmmm, I've totally neglected the latent heat of water that Guy details above. External heat source will work better, and then we're back to the steam rocket as described on its wiki page. Count Iblis (talk) 19:46, 12 September 2017 (UTC)[reply]
I see you haven't received a response to this so far. I suspect the question as posed isn't answerable because (a) human beings are extremely variable – an identical blow might be a mere annoyance to one person and fatal to another – and (b) tiny variations in how hard, where, at what angle etc., might make large differences to the outcome on the same person, as might that person's exact state of well being at the time. Crime fiction stories sometimes used to feature strong-arm men who could calibrate their blows with, e.g., a blackjack or cosh so precisely as to render the victim unconscious for a pre-specified number of hours: this was, of course pure fantasy. {The poster formerly known as 87.81.230.195} 90.200.137.12 (talk) 08:29, 13 September 2017 (UTC)[reply]
OK, let me add more details: assume that the person in question has a good chin, is in perfect health, and is pumped full of adrenaline (i.e. extremely pissed off, as is usually the case in an actual street fight), and that the blow is a well-placed (but not necessarily perfect) karate strike to one of his weak points (neck, chin, side of head, bridge or tip of nose, solar plexus, floating ribs, or crotch), delivered with a force which is just sufficient to break the stack of 4 boards described previously. (On second thought, let's make this even harder and assume that the person is not only pissed off, but is also high on crack and meth at the same time.) Is this likely to knock the person out, or at least disable him? 2601:646:8E01:7E0B:3DB7:8D6E:A762:14CC (talk) 11:22, 13 September 2017 (UTC)[reply]
Any blow to the head, neck, or even any other part of the body is potentially lethal. There is no safe impact range for a blow intended to "knock the person out, or at least disable him". Akld guy (talk) 23:47, 13 September 2017 (UTC)[reply]
So, does anyone know the answer to the question: Can an attacker such as that described above (healthy, with a good chin, pissed off, and high on both crack and meth) continue fighting after receiving a blow described above (a well-placed but not necessarily perfect karate strike to one of his weak points described above, with a force just sufficient to break a stack of 4 boards described above)? 73.202.74.122 (talk) 20:04, 14 September 2017 (UTC)[reply]
Humidity
When I left for work the humidity in my house was 32%. The house was closed up the entire time and no one was there. When I got home humidity was up to 58%. Why did it go up so much with the windows closed and no one inside? CTF83!07:12, 12 September 2017 (UTC)[reply]
Did you take a shower before you went to work? The steam from the shower, and wet surfaces in the bathroom, might have equilibrated out to the measuring instrument's location later.
Another possibility is that the house isn't closed up as much as you think (is there any ventilation or air conditioning etc.?) and the outside humidity went up, or hot air from the outside was brought in and repeatedly cooled off by A/C with moisture accumulating inside etc.
Even something like leaving the lid off a toilet tank has some effect on humidity (or at least, I've done that deliberately in winter believing it alleviated some of the worst of the dryness). Wnt (talk) 23:42, 12 September 2017 (UTC)[reply]
5) A poorly insulated house may have moisture condense out on the walls and windows at night, then evaporate as they warm up during the day.
6) Dripping faucets.
7) Wet dishes.
Also, the humidity may have stayed the same, on average, in your house, with it just evening out while you were gone. For example, if the bathroom or kitchen was humid when you left, that humidity would have spread to the rest of the house, making the reading higher outside those areas. StuRat (talk) 05:01, 13 September 2017 (UTC)[reply]
Request for help identifying this tree
Hello,
This is a small tree found in Kerala, a sub-tropical region in South India. It is about five meters tall and has rather catching foliage which causes it to stand apart from the rest of the trees in the neighbourhood. The fruit looks like an unripe guava but much smaller than a guava fruit. Yellowed ripe fruits were seen on the ground but instead of rotten fruits dried, hard, wood coloured ones were scattered under the tree.
https://ibb.co/fDZTtahttps://ibb.co/bZ3hKFhttps://ibb.co/moOtRvhttps://ibb.co/fGupzFhttps://ibb.co/j4uNKF
Can somebody help find out its name and classification? — Preceding unsigned comment added by 117.253.184.183 (talk) 07:23, 12 September 2017 (UTC)[reply]
I'm having some trouble finding leaves or other parts of the tree in focus. Ideally it would be nice to convert the structure of leaves and other parts of the plant to botanical terms. For example, our article on leaf venation gives me the impression that these leaves might be actinodromous, though looking at a better resource like [6] makes me wonder if that is so. But ... with a leaf in hand, and ideally a magnifying glass, you can say so much more than we can say from these photos. Once you have some botanical terms, you might be able to web search relevant trees. Another possibility is to take your guava guess and go through Myrtaceae (the guava family) in search of likely candidates -- though that is a lot to go through with no guarantee of success. Wnt (talk) 23:55, 12 September 2017 (UTC)[reply]
Re [7]. This morning at the bus stop I saw a woman with a device roughly the size of a cigar, looking rather like one of those cylindrical cigarette lighters. It wasn't just a cigarette in a holder (there was no glow or wisps of smoke coming from it) and it wasn't an e - cigarette. She held it to her lips and sucked on it and exhaled smoke after. Has anyone seen this before? Can it legally be used indoors? 81.139.183.197 (talk) 09:48, 12 September 2017 (UTC)[reply]
Which country was this in? I'm in the UK, we can't move for the things. Every high street now has one or more shops selling them. Some are the size of bagpipes. There are plenty that are cigar sized, so that the liquid tank and the battery can be large enough to last longer. Usually there's a smaller mouthpiece at one end, resembling an old cigarette holder. The early sort of skeumorphic cigarettes have fallen from favour, at least amongst those with serious habits.
No, you generally can't use them indoors any more. They're still legally vague, but most premises have now made their non-smoking signs specific to prohibit them. Andy Dingley (talk) 10:06, 12 September 2017 (UTC)[reply]
Not yet, although they're appearing for private cars, on the back of child safety justifications. In 2007 we imposed a massive indoor smoking ban on almost all premises (shops, pubs, restaurants, office) almost overnight, and with little opposition. As a result, the population of some towns went outdoors for the first time in years. Andy Dingley (talk) 10:15, 12 September 2017 (UTC)[reply]
And even outdoors, the property owner may impose a ban (e.g. railway stations, hospital grounds). Prisons and mental hospitals were exempt, but that has changed. However, mental hospital wards used to have open verandas on which smoking was allowed on a one - hour - on one - hour - off basis, which may still be the case. Of course, anyone who is not on a section is free to leave the ward and indeed the hospital at any time. 81.139.183.197 (talk) 10:27, 12 September 2017 (UTC)[reply]
Many e-cigarettes are not shaped like cigarettes, and some have similar shape and size to a cigar. What you saw was most likely a vaporizer, and no matter what the size or shape, still generally falls under the name of "electronic cigarette". SemanticMantis (talk) 14:56, 12 September 2017 (UTC)[reply]
It was almost certainly a vaporizer or an e-cigarette. If it wasn't an e-cig it may have been a "vape pen" or a vaporizer which are generally used for cannabis or cannabis extracts. Compare to the "Pax" brand vaporizer for consuming cannabis or cannabis extracts. Other vaporizers are designed specifically to vaporize cannabis extracts variously known as BHO, oil, and many other names. 204.28.125.102 (talk) 22:48, 14 September 2017 (UTC)[reply]
I am not sure what your question is, because the choice of words is crucial where you put pressure or "weight". If you are asking about whether it will change fuel consumption, the question is mostly about the drag coefficient of car+carrier with bike vs. car+extended carrier with bike (solid friction between the wheels and the road should be the same, assuming for simplicity that the trajectory of the carrier is the same in both cases - which will be wrong in mountain roads with a lot of turns etc. but I guess the question is mostly for highway).
if you are referring to weight of the car on the ground, the total weight is unchanged if the two carriers weigh the same. The weight on the rear tires increases slightly and the weight on the front tires decreases slightly. Theoretically, this will also very slightly tilt the car up at the front, which could result in more lift at speed, which will reduce the total weight on the tires and increase the drag, but I cannot believe this effect is large enough to notice. -Arch dude (talk) 16:47, 12 September 2017 (UTC)[reply]
If the weight of the bikes is extended some distance behind the car then the effect would be noticeable on the suspension on an uneven road, but most bikes are light compared with the weight of the car, so I agree that the tilt on a smooth road would probably not be noticed. Dbfirs19:47, 12 September 2017 (UTC)[reply]
By "extending the carrier farther outward behind the car", you appear to mean a carrier that is designed to be extended. I think you do not mean constructing an extension and bolting it to the existing carrier. Therefore, taking the first meaning, extending the carrier and moving the bike further out on it does not add any extra weight that the car has to carry. What it does do is increase the pivoting about the rear wheels that already existed. The carrier and the body of the car form a kind of lever that pivots around the rear wheels which act as a fulcrum. Moving the carrier and bike further out rotates the whole setup just a little more and transfers more of the weight off the front wheels onto the rear wheels. Therefore, the air pressure in the front wheels is relieved a little and that in the rear wheels is increased by the same amount. The same happens to the pressures that the wheels exert on the road. Neither the total mass of the car+carrier+bike nor their weight change. In a severe case, the weight on the rear of the car may be enough to lift the front wheels completely off the ground. I have seen this happen on a motorway when a light truck towing a trailer ahead of me travelled over an uneven surface at 100 kilometres per hour (62 mph). The trailer bounced the front wheels of the truck off the road, the driver lost control and both vehicles rolled over. Akld guy (talk) 07:22, 13 September 2017 (UTC)[reply]
I'm not sure that we have such data. While standardized tests have been used for a long, long time (in China some several thousand years), in the U.S., it wasn't until the 1980s that broad spectrum universal standardized testing came into being; earlier standardized tests were limited to specific applications (civil service tests, college admissions tests, etc.) the results of which would be hard to apply across all of a population because the test takers were not a random sampling. So, the data you seek likely does not exist for the U.S., and international broad-spectrum testing (where a random sampling of people from all over the world take the same test to compare results) certainly didn't exist. Honestly, the modern travesty that is the standardized testing industry, and the detrimental effect it has had on American educational quality dates only to A Nation at Risk, a report issued in 1983 whose results are based on sketchy presumptions and bad data, and which has been widely criticized since its release, despite (and also because of) its influence. --Jayron3211:18, 13 September 2017 (UTC)[reply]
I find it interesting that the Ancient Romans were better at war than science and got to rule Greece a few centuries but soon got their asses handed to them while the Greek empire endured 330AD-1453. And that the Greeks only fell when an empire good at STEM got through the capital's wall with a cannon so strong the carriage broke every shot. And that that empire too was nibbled away to almost nothing when Ottoman STEM fell behind. Sagittarian Milky Way (talk) 02:41, 13 September 2017 (UTC)[reply]
Well, it's a bit more complicated than that. Politically, there is no distinction between the Roman Empire and the Byzantine Empire. Culturally, however, the eastern half of the Empire was distinctly Greek and the western half was Latin. The question one should ask is which is more important, the political structure or the cultural one. --Jayron3213:43, 13 September 2017 (UTC)[reply]
I'd note that comparing test scores over time is always tricky anyway, since requirements etc change, unless you really use the same questions in 1950 as in 2018 which is problematic especially in science. If you consider the British system and those inspired by it (e.g. Malaysian, Singaporean), while there is often talk etc of how students did better this year than last, or lots of worries when there's the opposite, when you have even just a little bit of knowledge of how marking, question setting etc is done, as well as issues like Grade inflation, it's easy to see that it's not really clear whether these changes are meaningful and really reflect changes in achievement, knowledge etc.
That's even before you consider that even the nature of the tests themselves tend to change, as well as issues, particularly prominent in places like Malaysia and Singapore of how much the tests scores reflect the person's ability to use and apply knowledge, and how much of it reflects rote memorisation and learning how to take a test; and how useful the later is presuming you aren't intending the student to spend all their lives taking tests, i.e. even if the people are really achieving more than students 10 years ago, how useful are these achievements?
(There is an interesting issue here though, which also gets at Df's point. While places like Korea, Singapore or China don't seem to show great levels of STEM achievement at university level (albeit they do seem to be improving) compared to a place like the US or even the UK and this is often considered a sign that their systems aren't working as well as they should, it does seem that increasingly a big percentage of university students including at graduate level who do well are people who had a lot of their education in such places. This doesn't of course mean that their school systems are the reason for this. Or even if it is, that it's worth other possible costs. Or even if it is, that it's easy to replicae. Notably the fact that people of similar cultural background who gained most or all of their education in the US (or wheever) tend to likewise perform better on average would be a word of caution against any simplistic analysis.) P.S. Since I mentioned China and also PISA below, I should say I'm aware that China in PISA still does not come close to represeningt the whole of China.
However the question then becomes how do you consider the comment "probably not as good as it should be". I would argue that saying that given where we are in the world now as illustrated by our level of development and GDP per capita, we are not actually doing as good as we should be is not American exceptionalism (as your comments taken together would seem to suggest, even though I don't think you intended to) but a fair comment by an American. In other words, my main point with the GDP per capita etc was that based on PISA results at least, I disagree with your criticism of BB's comment, since the based on PISA and what we know about the US, they are not doing as good as theys should be.
While Gini coefficient is relevant, it doesn't IMO support your suggestion that BB's comment requires American exceptionalism. The Gini coefficient may make it less surprising but it doesn't make it significantly more acceptable. Fixing the STEM achivement problem isn't likely to solve the poor Gini coefficient by itself (which is wider sign the US are not doing as good as they should be in the world), but it is probably one factor especially since it's likely to be difficult to solve it without fixing wider problems in educational access.
To be fair, since there is no magic, you might argue that things are where they should be if they are headed in the right direction at the right pace since realisticly there's no quick solution to historical problems but whether with PISA or Gini coefficient, it's difficult to argue this is the case for the US. TIMSS results complicates things somewhat but I don't think we can ignore other assessements.
I appreciate that not everyone agrees that inequality is a major problem that needs to be solved, so I'm not suggesting everyone may agree with this view, but this is a different issue from whether it's American exceptionalism to suggest the US is not doing as good as they should be because self measures show they should be able to do better. (I.E. These people are saying they do not think these measures suggest the US has major problems because they disagree they matter much or at all; they aren't saying relatively the US is doing okay since there's no reason to think we should be able be doing better.) Likewise, some or many of the political solutions to the problems in the US may actually have made things worse because they concentrated on the wrong issues, but this doesn't mean the US is doing as good as they should be except on a level of "well our political systems is screwed up so it's not surprising".
Most of the answers above have to do with the average level of achievement. If instead one chooses to compare the best of US STEM accomplishments to the best of other countries, then the US often comes out looking somewhat better than if you only consider the average. Achievement, so to speak, is not evenly distributed through the US society. For example, the US is at the top or near the top in things like the number of Nobel prizes, the rankings of universities in STEM fields, International Mathematics or Science Olympiad medals, number of academic papers published per year, value of STEM related businesses, etc. Admittedly, some of that is because the US is a rich country that can import top talent from other countries; however, I do think the US has historically had a culture that favored scientific investment and high-level achievement. That hasn't always trickled down to STEM awareness and achievement in lower education though, where large disparities still exist related to geography and income, etc. Dragons flight (talk) 12:51, 13 September 2017 (UTC)[reply]
See my note about the Gini coefficient for why this dichotomy exists. The difference between the best academic performance in the U.S. and the average academic performance in the U.S. is closely correlated with economics. The richest Americans are also much richer than the average Americans. Those two facts are likely tied together in important ways. The question facing America (which is the closely tied to the same political question which divides our two parties and their philosophy) is whether to measure success by the best or by the most. In the U.S. you get two different answers for both economics and education. --Jayron3213:48, 13 September 2017 (UTC)[reply]
Yes, wealth distribution is very important, particularly for education in the USA, where funding and access to education tends to be locally controlled, and thus segregated by wealth, socio-economic status, race, etc. Most of our states in the USA have world-class schools for rich kids. Few of our states manage to provide good education for the poor. SemanticMantis (talk) 16:07, 13 September 2017 (UTC)[reply]
Sure, it's more than just providing more resources to rich kids, but providing more resources to rich kids is definitely a problem, and it happens all over the county [8], if not your county. Even if your county spends equally per pupil, the linked map shows that a) it is well behind the USA's national average and b) the children in the counties to your left will have more money spent on them. I completely agree that evaluating based solely on student performance is problematic. While it is true that poor students' learning depends less on teaching quality than middle or rich kids, quality of resources and educators still matters. I think there's a case to be made for spending more per-pupil on the poor kids, as equal funding is apparently not leading to equitable outcomes, but I won't be holding my breath (e.g. this [9] famous illustration). SemanticMantis (talk) 18:29, 13 September 2017 (UTC)[reply]
(Congrats on the longest link I've ever seen.) I suspect that a lack of reading in poor homes causes the regression. However, I don't suspect that lack of money causes lack of reading but more the other way around. Households that don't encourage reading and other learning have kids who grow up to be poor and continue to discourage learning. Apparently kids watching Housewives of <insert random city here> isn't the rocket straight to the top we all assumed it would be. StuRat (talk) 18:19, 13 September 2017 (UTC)[reply]
The BBC is running an investigation on why summer born children achieve less than children born at a different time of the year, a disadvantage which continues throughout life [10]. I've not been following (the series is called Whodunnit: The Calendar Conspiracy) but I assume it's to do with the fact that the school year begins on 1 September, which means that summer born children are the youngest in the class. The effect is also explored in Malcolm Gladwell's book Outliers[11] but the parameters are slightly different. The remaining programmes air at 13:45 BST on Radio 4 tomorrow and Friday and you can catch the whole series on iplayer. 92.8.216.51 (talk) 20:17, 13 September 2017 (UTC)[reply]
Tuition fees for US universities are astronomical, it's of the order of a year's income. But students obviously are not getting anything close to a personal tutor, so they are in fact paying for the wages of the top researchers. Count Iblis (talk) 08:41, 14 September 2017 (UTC)[reply]
My first thought for "06W" was "West", i.e. it travelled 6 degrees east-west. Consider these four storms:
1985, 06W
1978, 19W
1981, 26W
1974, 34W
As you go down the list, each one had a net east-west difference that's greater than the one above it. That got shattered, however, with the 1971 storm, 37W, which started and ended near the Philippines. Their starting locations aren't correlated with the numbers either (e.g. 1971 and 1985 both started vaguely near Guam), so the numbers definitely don't mean "degrees west of the antimeridian". Nyttend (talk) 01:37, 12 September 2017 (UTC)[reply]
The first name is assigned by Joint Typhoon Warning Center (JTWC) in Hawaii. The second name was used when it was in "area of responsibility" of the Philippine Atmospheric, Geophysical and Astronomical Services Administration. Perhaps the number was assigned by the Japan Meteorological Agency (JMA)? Rmhermen (talk) 01:39, 12 September 2017 (UTC)[reply]
I believe this is the 6th tropical depression of 1985 in the Western Pacific (I don't know if subtropical depressions count). Atlantic storms are called L (01L, 02L and so on), Invests (potential tropical depressions) are called 90L, 91L through 99L then 90L, 91L and so on and other basins have other letters like E for East Pacific. The "L" is probably for AtLantic. Sagittarian Milky Way (talk) 05:41, 12 September 2017 (UTC)[reply]
How much of out genes is a results of what our mates chose as appropriate or desirable? What traits died out because no one wanted to mate with humans carrying those traits? --B8-tome (talk) 18:58, 13 September 2017 (UTC)[reply]
See sexual selection. But note that only a tiny portion of genes are different between men and women (1 in 46 chromosomes is different, X versus Y, but not entirely different), and presumably only a small portion of those differences are due to sexual selection. If you want a specific trait that died out due in part to sexual selection, perhaps being covered with body hair might qualify. Being hairy meant they were more likely to have parasites like fleas and lice, and having those does tend to be a turn-off, because they can spread to mates. However, the use of animal skins as clothing was also critical in this process, as otherwise hairlessness can cause death from exposure. StuRat (talk) 19:33, 13 September 2017 (UTC)[reply]
This is very misleading. Only a small number of genes are differentially present in men and women, but a greatly larger number of genes are differentially expressed. The Y chromosome only contains a small number of genes, but those genes control the activity of many, many other genes located on other chromosomes. The small size of the Y chromosome really has no impact on the possibility of sexual selection. Looie496 (talk) 23:12, 13 September 2017 (UTC)[reply]
Note that sexual preference is itself subject to natural selection on the very long term. While this phenomenon was discovered in exceptional cases where sexual selection leads to a net disadvantage, sexual preference will have had an effect on evolution for many hundreds of millions of years and must therefore itself have been subject to natural selection. E.g. prey animals can happen to get into a situation where there are far fewer predators than usual for many generations. Sexual selection will then determine the genetic make-up of the offspring to a larger degree than usual. But the predators will be back later so, on the long term, a sexual preference that has a similar outcome whether there are are predators or not, is the one that's going to be selected for. Count Iblis (talk) 01:58, 14 September 2017 (UTC)[reply]
Proximity tends to be a huge factor in choosing a mate. It is rather uncommon for a person to mate with someone that is too far away. Instead, they tend to choose mates within the tiny group of people that they have contact with. 209.149.113.5 (talk) 11:40, 14 September 2017 (UTC)[reply]
The issue isn't that 97% of climate scientists agree. The issue is what they agree on. What they agree on is that there is a warming trend of up to 0.8 degrees in the last 150 years and they agree that there has been an increase in fossil fuels during the last 150 years. They do not all agree that the warming is completely caused by use of fossil fuels. They do not all agree that the trend will continue. They do not all agree that the trend will accelerate. They do not all agree that ending all use of fossil fuels will reverse the trend. However, this does not mean that less than 97% of climate scientists do believe that global warming is going to be an ongoing trend and that it is caused by man. This is the best analysis that I've seen on the topic of consensus. It makes it clear that while the consensus for any specific subject may be lower (or higher) than 97%, it is still well over 90% in general. 209.149.113.5 (talk) 15:09, 14 September 2017 (UTC)[reply]
Also keep in mind what a moving target this is. New scientists are minted every year, scientists die every year, etc. There's really no use in nitpicking exact percentages on something like this. Science isn't a popularity contest. SemanticMantis (talk) 15:52, 14 September 2017 (UTC)[reply]
Also also important: Science is not built on single "gotcha" moments, nor is it built on certitude. It is built on consensus, and it is built on the preponderance of evidence. "I did the calculations, and it's only 96%! HA! It must all be a hoax!" is the sort of bullshit that the creationists and the ID crowd and the climate change deniers engage in. The fact that consensus is clear, evidence is overwhelming, and we're damned sure that climate change is happening and is caused by pollution are not in serious dispute. The disputes are over things like mechanism, degree, small differences in specific theory, and the like. The broad picture is well agreed upon. --Jayron3215:59, 14 September 2017 (UTC)[reply]
Rubbish blog talking about no change in the last 15 years. Even Roy Spencer's graphs show the trend even though he believes that God would not allow such a thing and he refuses to put in anything except horizontal average lines on his graphs. Dmcq (talk) 16:32, 14 September 2017 (UTC)[reply]
The trouble is, certain journalists thrive on the use of imprecise language, weak attribution of claims, and unscrupulous use of statistical fact. These behaviors would be called "weasel words" if an author posted them to Wikipedia. In high-visibility newspapers, authors get paid for using these tactics!
Well-written scientific news carries at least the following characteristics:
reference to further information, data, and analysis for interested readers to explore the topic in further depth
If you're reading a science-news website that does not do all of those three things, you're not reading a good science news website.
In this case, the author of this Forbes opinion piece constructs a straw man argument. He poses questions that he does not expect us to answer, probably for the sake of promoting doubt. I would call that disinformation - or at the very least, pretty disingenuous, and poor-quality journalism, even for an op-ed piece. He writes: "What exactly do the climate scientists agree on?" Well, if he read the paper he pretends to be criticizing - Quantifying the consensus on anthropogenic global warming in the scientific literature (2013), the paper is pretty specific. "Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming."
Now, if the critics want to attack the methodology, that's fine - they can bring their legitimate criticisms. But if they simply ask obtuse questions - "What exactly do the climate scientists agree on?" ... then there are very easy answers to their ill-informed questions. The climate scientists agree that "humans are causing global warming." This is the statement that Cook et al. found agreement upon. "How do we know the 97% agree?" "We analyze the evolution of the scientific consensus on anthropogenic global warming (AGW) in the peer-reviewed scientific literature, examining 11 944 climate abstracts from 1991–2011... "[Cook et al] classified each abstract according to the type of research (category) and degree of endorsement."
See? Easy answers exist to refute an ill-conceived critique.
Perhaps instead of reading opinion-pieces on Forbes.com, our readers would consider reading a better science news website, where interesting and difficult questions about climate and policy are brought forward? Here's a front-page story from the website of the U.S. Energy Information Administration - EIA projects 28% increase in world energy use by 2040. What are we going to do about that? Why doesn't our esteemed op-ed writer tackle that question in his next piece?
Well, the first page of the article is fairly easy to debunk. It was the second page I was more interested in. I was curious if these quotes were taken out of context or the article was omitting anything. So far, I've researched the first quote and it appears to be accurate. In fact the guy quoted, Richard Tol, did write an interesting article critiquing Cook's methodology: The claim of a 97% consensus on global warming does not stand up. What the Forbes opinion piece neglects to explain is that Tol was only criticizing Cook's methodology, not the scientific consensus on AGW. A Quest For Knowledge (talk) 19:26, 14 September 2017 (UTC)[reply]
The theory that the world is heating up is probably a result of statistical mis-analysis. The temperature records that have survived from 150 years ago are sparse and are heavily weighted in favour of capital cities, which are usually harbour cities and therefore cool. Since the 1960s a boom in technology has allowed the placing of temperature sensors in remote places where readings were never historically taken. A boom in computer technology since 1990 has allowed the storage of all this recent data. What we are seeing is not a rise in temperature but a more accurate figure for the world's temperature. I have never seen any analysis by scientists of the implications of this statistical bias. Akld guy (talk) 19:44, 14 September 2017 (UTC)[reply]
Akld guy, before you self-congratulate as the sole genius who has figured out the grand conspiracy, you should know the following.
You are making certain specific claims that are:
commonplace claims often repeated by ill-informed people
claims that are easily, and commonly, refuted by actual scientific study
The claim that recent data or methodology is inconsistent with older data and methodology
Both claims are wrong.
Urban heat island effect is very well known, very well characterized, and responsible climate-scientists account for this effect. Here is EPA.gov's website on the heat island effect; and here is the National Climatic Data Center's FAQ on temperature data. Refer to "Q5: Are there still biases in the data we use to calculate global and U.S. temperatures?"
Once again, we can easily refute your criticism. Your criticism is neither valid nor correct; and it's not even original. It's the same tired line that has been repeated by many poorly-educated people for, well, a really long time. Before you were even born, uneducated people were saying that urban heat islands perturbed climate science; they were wrong then, and they are wrong now.
Absent any reliable reference for your claim, you should not repeat your claim on this encyclopedia's science reference desk. You say you "have never seen any analysis by scientists of the implications of this statistical bias." Here are six analyses:
Do you really want more, or would you like to rescind your ill-informed commentary?
For your own sake, spend an hour studying climate science before making strong statements about it. Even better - spend a few thousand hours studying it - because that magnitude of formal study is exactly what climate science professionals get.
Yeah, whatever. Scientists are not statisticians. You do realise don't you that adjusting for bias because of incomplete statistics from long ago is error prone? Extrapolating new figures based on a limited subset is prone to error. In short the comparison is being made on a limited set of figures, expanded out to give a multitude of new figures, versus the latest figures from sensors where readings were never taken. It's just nonsense. Akld guy (talk) 21:42, 14 September 2017 (UTC)[reply]
Scientists can be statisticians, or mathematicians, or whatever.
The author of the first study I linked, Tom Smith, has "degrees in mathematics, meteorology, and oceanography." I'd be willing to bet money that he's got three more degrees than you've got in the geosciences. Multiple universities, organizations, and agencies have validated his credentials; his papers passed peer-review, meaning that panels of experts in climate and statistics checked his work. I also cited many many more authors and publications, so if you don't like the first one, and you don't like the next paper, and you don't like the next author's credentials, and you disagree with the next paper's methodology.... well, the statistics just aren't in your favor, are they? How about 11,000 more research publications, do you still want to nitpick each of the authors' credentials on that stack of research as well?
If you disagree with the majority of experts, you are the fringe scientist crackpot.
This data is vetted by scientists and statisticians. The methodology is correct and sound. You are mistaken, and instead of being argumentative about it, you should take some time to inform yourself.
Imagine a room completely filled with hydrogen and no oxygen. A match is somehow struck in this room. Does it light? Does the room explode with flame? Or is oxygen needed for the reaction? Basically, does hydrogen require oxygen to burn? †dismas†|(talk)19:15, 14 September 2017 (UTC)[reply]
Hydrogen requires oxygen to burn. Flame, in the conventional sense, requires the three parts of the fire triangle: fuel (hydrogen); oxidizer (from the oxygen in the air); and a spark (the heat from friction during the strike of the match).
Interestingly, though, a match probably does not require oxygen from the air - depending on the type of match, it may contain (or may be struck against) an oxidizing chemical, allowing the flame reaction to occur (for a brief time) independent of any oxygen in the air. If the room is totally oxygen-free, that flame will rapidly extinguish.
For the record, we're restricting to discussion of conventional chemical combustion. You need an oxidizer; in a normal room on Earth, that oxidizer is usually oxygen.
Chemical combustion ("flame") can also exist in an atmosphere of chlorine or fluorine; or in appropriate mixtures of perchlorate, and so on. In yet another case of chemistry that is more difficult than the version we learned in high school, sulfur can burn hydrogen under certain conditions; sulfur acts as a weird simultaneous "fuel-and-oxidizer" in that reaction. If you mix hydrogen and sulfur dioxide, sulfur will even un-oxidize from the oxygen and re-oxidize with the hydrogen; under other conditions, the reaction goes the other direction[18]. All of those chemicals will "burn" hydrogen in a chemical reaction. A 100.0% hydrogen atmosphere, however, can not sustain a flame.
If you want to start mincing words, we can also redefine the plain english word, "burn", to encompass the totally-different physics and nuclear chemistry called hydrogen fusion. This is actually a commonplace abuse of language among people who study stars, for example: if you read our article on Stellar nucleosynthesis, you see the word "burn" used throughout the article.
Well they were both faster than me, so I'll just say Nimur and Shoy are right (well, Nimur might be right or wrong about specialty matches, I don't know). But while we're all here, anyone know why the the table at Flammability limit#Examples has different values for UFL and UEL for hydrogen? I noticed it while preparing my now-superfluous reply. UEL=58%, UFL=75%. The source has the same thing: [19]. None of the other materials have different values (some have ranges). And the way I use UFL and UEL in real life (admittedly not pure chemistry, and not with hydrogen) they're defined identically. --Floquenbeam (talk) 19:48, 14 September 2017 (UTC)[reply]
At the risk of sounding like a commercial endorsement, these matches burn underwater (and in sand). To scale back my earlier claim, these matches are specialty-items and are not commonplace.
These matches are a real-world example proving that some flames cannot be extinguished. Such materiel embeds the oxidizing chemical into the fuel and once ignited, the fire cannot be extinguished because it self-completes the fire-triangle. Nimur (talk) 19:56, 14 September 2017 (UTC)[reply]
Okay, if you can cool it fast enough, by blowing inert gas over the fuel/oxidizer mix, you can make the reaction unsustainable. Moving the ambient air might prevent it from incandescing, and the flame might go out. Nimur (talk) 22:02, 14 September 2017 (UTC)[reply]
A safety match should strike and burn in a hydrogen filled room. (A weird thing is that the ignition of a humble safety match is chemically the same as Armstrong's mixture, which is perhaps the most infamously hazardous thing a pyrotechnics wannabe can attempt to make. But the match and striker are physically separated. Wnt (talk) 00:55, 15 September 2017 (UTC)[reply]
Cassini
is there any prediction of what happens when she crashes through Saturn? Treasure trove of data coming in 20+ hours but would be nice for the article to compare what is expected.
JPL has a great website on the event: JPL's Saturn Website main page presently has a special - Cassini: The Grand Finale. Here's an interview with several of the program scientists, including a description of what's about to happen in the next few hours as the spacecraft enters Saturn atmosphere. The spacecraft will begin to aerodynamically tumble, eventually enduring aerodynamic stresses beyond its ability to maintain directional control. The spacecraft will no longer be able to point its antenna toward Earth; and will tumble unpredictably before ultimately breaking apart. Here's a more detailed overview: Cassini Spacecraft Makes Its Final Approach to Saturn.
"Within about 30 seconds following loss of signal, the spacecraft will begin to come apart; within a couple of minutes, all remnants of the spacecraft are expected to be completely consumed in the atmosphere of Saturn."
Here's a long-form documentary, (about 15 minutes long), from earlier this summer; it includes some stunning animations representing what NASA's digital artists think the spacecraft break-apart would look like if you could watch it with your own eyes at Saturn.
It's a little hard to understand intuitively, but the material of the spacecraft will be hitting atmospheric gas, as dense as Earth's sea-level atmosphere, while it's still moving at orbital entry speeds - about 70,000 miles per hour (or about twenty miles each second). At those speeds, the heat of aerothermal friction is so high that even space-grade metals - like titanium - or ceramic or composite structures - just can not withstand the heat and stress. Hitting air molecules at that speed can be as destructive as slamming into a solid object.
This link - JPL's Cassini Grand Finale interactive feature - is a fun tour of the last hours of mission operation, full of cool animations and brief descriptions. The feature explains which parts of the spacecraft are expected to break off first, using language that's accessible to an average science enthusiast.
"Cassini’s gold-colored multi-layer insulation blankets will char and break apart, and then the spacecraft's carbon fiber epoxy structures, such as the 11-foot (3-meter) wide high-gain antenna and the 30-foot (11-meter) long magnetometer boom, will weaken and break apart. Components mounted on the outside of the central body of the spacecraft will then break apart, followed by the leading face of the spacecraft itself."
@Nimur: fascinating, and I am an "average science enthusiast," but I thought that the atmosphere is way stronger than ours?
Further, is there a remote possibility (in probability theory there are no absolute certainties (or vice versa) she can survive to send back more data? I realize even at this point IFF it happens she;;ll [almost] certainly never leave Saturn.Lihaas (talk) 20:55, 14 September 2017 (UTC)[reply]
Saturn is an enormous planet. The spacecraft's orbit will take it over the "cloud tops," and as it descends, it will encounter denser atmosphere. The air will get about ten times as thick for each minute the spacecraft falls.
There is no realistic way for this spacecraft to survive the plunge into the planet's atmosphere. It is not structurally designed for reentry; it has no heat shield.
Even if the spacecraft survived, it will begin tumbling as soon as the atmosphere becomes thick enough. Once the spacecraft is tumbling, it cannot point its antenna at Earth, so we can not hear any messages it sends to us. We'll be pointing the most sensitive antennas on our planet - Deep Space Network - using an antenna in California and another in Australia. Even with our most sensitive antennas, we can't detect Cassini's signals after it starts tumbling.
The mission planners know that is going to happen - so they've configured the spacecraft to send as much data as possible before it hits the planet; and to transmit as much as possible on the way in.
No part of the spacecraft will remain intact: it will be evaporated by the intense heat, like a meteor.
Is any other outcome possible?
No.
Several years ago, after I read the Wikipedia article on "almost surely", I had a long and boring conversation with my mathematician friend. We took that article apart piece-by-piece. We did a verbal epsilon-delta proof. We constructed a Lebesgue measure for the probability integral. We took the language apart, constructed a grammar, used axiomatic set theory. We talked about alternative views on the issue, colored by my various backgrounds in physics, in engineering, in philosophy. We talked about using probabilities as inputs to decision problems in game theory. We talked about plain English words, and the very same words used in technical mathematical parlance. We talked about "certainty," and "good-enough-certainty." We came to no new profound understanding.
Quibble regarding "the heat of aerothermal friction" -- my understanding is that friction plays a small part in the heating of a spacecraft (or meteor) on atmospheric entry. The main heating effect is caused by the compression of the air in front of the object. Atmospheric entry says "Direct friction upon the reentry object is not the main cause of shock-layer heating. It is caused mainly from isentropic heating of the air molecules within the compression wave." CodeTalker (talk) 22:17, 14 September 2017 (UTC)[reply]
Good observation; I'm lumping all of the aerodynamic heating effects together. Reentry thermodynamics, as you point out, become very complicated. Nimur (talk) 23:06, 14 September 2017 (UTC) −[reply]
Any chance bacteria can survive? There are water vapor clouds and comfortable temperatures near the bottom of the observable cloud layers. (The gravity is Earthlike also, so any relevant microbes need to be able to hang aloft for long durations) Wnt (talk) 00:57, 15 September 2017 (UTC)[reply]
Extreme(ly foolish) Airbrushing
I want to use a cheap airbrush to spray clothes-washer grade bleach on some clothes dyed using natural colorants. What kind of bleach is a better choice, chlorine-based bleach or peroxide-based bleach?
Chlorine-based bleaches are sold as aqueous solutions. They are very likely easy to spray.
Peroxide-based bleaches are mostly sold as dried powders and must be dissolved in water before use.
I want to "paint" on the clothes using the bleach. I will do it outdoors in the open and wear rubber gloves, eye protective and a breath mask. I just want to know which kind of bleach is relatively friendlier to the airbrush which is made of stainless steel and rubber O-rings. -- Toytoy (talk) 01:34, 15 September 2017 (UTC)[reply]
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