Carrock

It might be an idea to ask the parent, who will be better able than the child to decide the financial implications of paying for treatment and how likely the cost of treatment is to be fatal. Or advise them, if they survive their injuries, to move to a country where medical treatment isn't reserved for the rich and people without money are not left to die of exposure.

One option which doesn't seem to have had much attention: Split the the spacecraft into two masses: one for crew habitation and the other 'not wanted on voyage'. Attach the two with a cable long enough to make coriolis force etc not a problem and spin up for 1G in crew quarters. This wouldn't be simple or cheap but it may be more cost effective than other options.

Unsurprisingly, using typical human assumptions, we are more intelligent than any other animal, mainly or entirely because of our advanced language skills. Many harmful memes, mostly about defying instincts honed over millions of years reduce our survival chances; harmful habits among other animals usually die out within a few generations as they have no means of retaining those concepts for thousands of years. Language has created in most humans a partial loss of awareness of 'unconscious' bodily functions and instincts; we are probably less able than many animals to control these in an intelligent way. An example of clever animal/stupid human. Each is caught out in cold weather with inadequate fur/clothing hours from food and shelter. The animal increases its metabolic rate, knowing (in a nonverbal way) that it has enough fat reserves to stay warm until it reaches food and shelter. Without foresight or conscious control, the human's metabolism adjusts to conserve energy to enable the human to survive for days; the possible loss of a few fingers or toes to frostbite is better than starving to death. Various forms of yoga and meditation (specifically not Hatha yoga) can be used to improve awareness; for example to increase voluntary control of metabolic rate. A key part is chanting a repetitive phrase (eg 'om mane padme hum' or 'three one four one five nine') to disable verbal thinking in favour of the sort of thinking most animals do most/all the time. Humans frequently use drugs, whether medical or recreational or performance enhancing when those techniques would work just as well with few if any significant side effects. One common side effect is enhanced endorphin production, which can produce euphoria, vivid dreams, hallucinations and apparently religious experiences. I only got the first two.

You seem to be confusing the 'Shannon limit' with bandwidth efficiency i.e. Transmission Rate/Channel Bandwidth. Or you're being disingenuous about the 'Shannon limit.' Argument by Wiki from your Wiki quote https://en.wikipedia.org/wiki/Broadband] Breaks a 'Shannon limit' unless extreme techniques (far more expensive than just upgrading to fibre optic) are used to reduce noise. From another Wiki https://en.wikipedia.org/wiki/Very-high-bit-rate_digital_subscriber_line Plenty of data about VDSL standards in this Wiki. Is this an example of what you mean by 'getting around the Shannon limit'? To install broadband: Remove the bandwidth limiting filters between broadband modem and exchange to increase line capacity from about 56Kb/s to (say)5056kB/s. A 5056kB/s broadband channel would be nice but doesn't break the 'Shannon limit.' So assign a 56kB/s channel (up to ~ 4kHz) for analogue phone. Assign a 5000kB/s channel for broadband. 'Shannon limit' refers only to one channel ie the 56kB/s channel so the 5000kB/s channel breaks the 'Shannon limit.' So by increasing the number of channels the data rate has increased from 5056kB/s to, er, (56kB/s + 5000kB/s). The concepts that double sideband suppressed carrier is impossible and that the 'Shannon limit' can be overcome by multiplexing are so contrary to current knowledge that they should be confined to speculations until you provide evidence to support them. I notice your OP http://www.scienceforums.net/topic/97477-signal-modulation-how-much-data-can-be-set/#entry937903 has been voted up so presumably at least one person accepts the above concepts as mainstream science.

[latex]\cos (\theta )[/latex] can be negative so why not A? An amplitude modulated carrier with [latex]A=1 + B\sin(\omega_{i}t)[/latex] ie [latex]A>=0[/latex] suitable for a simple diode envelope detector: [latex] y = (1 + B\sin(\omega_{i}t))\sin(\omega_{c}t) [/latex] where [latex]B <=1[/latex] (normalising the carrier amplitude and only using sine wave modulation for clarity.) Multiplying out: [latex] y = (B/2)\cos(\omega_{c}-\omega_{i})t + \sin(\omega_{c}t) - (B/2)\cos(\omega_{c}+\omega_{i})t [/latex] ie [latex]y = [/latex]lower sideband and carrier and upper sideband A balanced modulator can be used to balance out the carrier ie: [latex] y = B\sin(\omega_{i}t)\sin(\omega_{c}t) [/latex] Multiplying out: [latex] y = (B/2)\cos(\omega_{c}-\omega_{i})t - (B/2)\cos(\omega_{c}+\omega_{i})t [/latex] As I mentioned in my previous post, the carrier and/or one of the sidebands need not be transmitted; they merely make tx and rx design easier, while wasting power and bandwidth. My falsifiable understanding is that wired broadband uses only available bandwidth of the wiring between broadband modem and local exchange high bandwidth multiplexer. I used to work on digital repeaters for digitised multiplexed phone calls using time, frequency and space multiplexing before optical fibre came in; bypassing 'Shannon's criterion' would have rendered my work on maximising bandwidth nugatory. I largely agree with the rest. In future please respond to my posts directly rather than editing quotes attributed to me.

In AM you can 'modulate' the carrier below zero. In single sideband suppressed carrier you are basically just frequency shifting the original modulation. This was widely used in long distance analogue phone lines and in commercial and amateur short wave comms. Reference please. Depends what you want. There's generally a sharp threshhold for digital; you go very quickly from 'accurate and reliable' to nothing at all. High redundancy modulation such as SSB and CW generally has a very soft threshhold, very useful in the presence of heavy interference or noise. Morse code is the best for low bandwidth comms when used by experienced humans; not very good for machines.

A few months ago I gave linux a retry - it's now far more user friendly and much faster than windows 7. Works for most things, with a windows (non) emulator like wine if needed and if it doesn't I can reboot to windows 7 or xp and have a leisurely coffee while it's booting. It's important to use a 64-bit version to overcome windows 7 upwards' insistence that any other os is a virus. The only real disadvantage of dual booting is that your computer is still vulnerable to windows boot viruses. Test and installation instructions: e.g. for linux mint: https://forums.linuxmint.com/viewtopic.php?f=46&t=91140

When there is an imbalance between quote and \quote tags the post changes each time it's previewed. Very easy to do with cut and paste of unformatted text. Lokks like that's what happened with http://www.scienceforums.net/topic/96920-clocks-and-rulers/page-8#entry937263

From the first survey I looked at: http://www.livescience.com/963-lags-world-grasp-genetics-acceptance-evolution.html or see a graph at https://www.buzzfeed.com/expresident/acceptance-of-evolution-by-country?utm_term=.xazl9Vekw#.mvNX7vJnY What survey(s) are you looking at?

I was referring to 'we can survive permanently down to just above half the present oxygen concentration at sea-level.' As only trees are destroyed, presumably on a continuing basis, I'd expect everything but trees to increase to replace the trees.

As the falling oxygen will be replaced by increasing carbon dioxide the question is whether global warming or carbonic acid poisoning will get us first!

From http://www.snopes.com/science/well.asp NASA has wisely given up disproving Apollo hoax theories. It's easier but just as pointless as proving each and every biological structure has not been intelligently designed.

If the book exists, its claim is false so I won't be reading it.

When the commander gets killed by friendly fire, all his troop will demonstrate team spirit by agreeing his death was an accident.

In the real world, how long does it take to write/generate the unbounded finite sequence 1,2,3,4,5,[...]? ([...] represents the numbers I didn't have time to write) It's impractical to continue up to even the number of electrons in the observable universe (or some finite number you choose) and you will never reach infinity as each successive number is finite. Much of mathematics is shorthand for something impractical or impossible to work out with basic arithmetic using pencil and paper.. If you think the above math is ok, what is the problem with being unable to write every term in an infinite sequence? [crossposted with Strange]

Some ordinary diodes like the glass protected OA79 produce detectable current if you shine a bright light on them. They don't require light to permit external current to pass through the internal diode and nor do solar cells. If you accept this diagram as accurate you will note note that your diagram is essentially equivalent to two of those in series. If one cell gets no light and its equivalent current generator drops to zero, the current that the other cells would produce can pass through the still forward biased internal diode. The purpose of the added zener diodes in your circuit is to permit current to pass if a solar cell goes partially or completely open circuit and probably to limit the array's maximum off load voltage. If, say, a rooftop solar panel in a location with mains power is reliable enough that spending £3 on diodes would on average increase lifetime enough to produce an extra £1 of electricity, I wouldn't condemn a designer for failing to include those zener diodes.

A few errors in the above: The main reason for a series diode is to prevent the cells being damaged in darkness by reverse voltage. If current is being taken from a partly lit battery, a cell in darkness is still forward biased but the diode (in the model) only passes external input current with no additional photocurrent; it absorbs rather than produces energy. It's possible to bypass a faulty or unlit cell but more than a simple diode is needed.

From https://en.wikipedia.org/wiki/Theory_of_solar_cells This shows clearly that a series dark cell is a forward biased diode if the other cells are producing current. It's common to include a low forward voltage (eg Schottky) diode in series to prevent cells at night eg discharging batteries charged in daytime. If illumination is uneven, or to guard against a cell going inefficient, a Schottky diode could be placed in parallel, conducting only if the cell is dropping rather than raising voltage. The last thing you want in a solar cell is a low forward voltage drop.

Without analyzing this equation I agree with your conclusion. I hope we agree that the gravitational potential distant from the BH is higher than it is near the BH. From the above ref: 'curvature=energy' is an oversimplification. More precisely, curvature is caused by energy and a lesser amount of energy is associated with the curvature. The negative gravitational P.E. near the BH ensures that there is lower energy density in that curved space than in distant 'flat' space. Agreed. However due to the negative gravitational P.E. near a BH the curved space has a lower energy/density than distant space. If gravitational P.E. is ignored it would have higher energy/density due to curvature. Ignoring gravitational P.E. the energy density increases as you approach a BH. I don't recall disputing this. Including (negative) gravitational P.E. the energy density decreases as you approach a BH. I don't think I'm missing anything. Sorry; I misunderstood. Do we agree about negative gravitational P.E.?

quote #1 quote #2 Robittybob1: I regret saying I was done with this thread. I've found it difficult to work out the conventions used above, especially as my understanding of GR and especially black holes is limited. You seem to have a similar problem. I'll go back to my Apollo example and use a pseudoclassical qualitative (ie mostly accurate) approach using what I think are Mordred's conventions. I'm sure he'll quickly correct me as necessary. In the Apollo capsule special relatvityish reference frame: As the capsule falls towards earth tidal forces (from the nearer part being increasingly attracted to earth more than the more distant part) increase; the increasing stress gives the capsule more energy - analogous to quote #1. If the tidal tidal forces were sufficiently large, the capsule would be torn apart and form an accretion disc. Setting the capsule's gravitational potential energy at all times to 0 (quotes #1 and #2), the earth/moon's gravitational potential energy increases enormously as the capsule falls. [Mordred may be using an event horizon or similar as a reference, with similar effect.] With this approach, the capsule's kinetic energy, transformed to heat in the atmosphere, has been created from nothing as has the increase in gravitational potential energy of everything but the capsule. All this for a special relativityish approach when general relativity would be more helpful - specifically using a distant place as an unchanging reference for gravitational potential energy. A rehash of a conventional energy conservation approach using distant gravitational potential as a zero reference: As the capsule falls its gravitational potential energy reduces [becomes more negative] and is transformed to kinetic energy, a little gravitational radiation, heat etc. The increased (tidal) energy in space around the capsule is far less than the reduction due to lower gravitational potential energy. Dealing with two orbiting BHs is much more complex but a similar approach can be used. We might have to look at that in another thread. It doesn't seem right for there would have to be some mechanism to replenish the energy on the outside if that was the case. Using an energy conservation approach: The energy for gravity waves does not originate from the spacetime geometry outside the event horizon. Nor from within. Set gravitational P.E. at zero at great distance from the BH. As a mass (or another BH) approaches the BH its gravitational P.E. becomes increasingly negative due to the BH's gravity and this P.E. is transformed to kinetic energy, heat, gravitational waves etc. As above, with limited exceptions due to extreme conditions, the locally higher 'tidal' energy aka 'spacetime geometry' is less than the negative P.E. Spacetime geometry does not originate energy for gravity waves. All of the energy produced is from the incoming mass interacting with the BH's gravity and other incoming masses. Black holes and their environs do not create energy.

Surely it has at least zero point momentum.

You don't need the reference to claim that black holes create positive gravitational energy i.e. 'a region of higher gravitational potential' in violation of those conservation laws. As you will not clearly state whether you consider gravitational energy to be positive, at least where black holes are concerned, in violation of conservation laws, I'm done here.

We're entirely agreed; the latter sentence is not contentious. From the reference equation 43 is a mathematical formulation of energy and mass conservation laws; there is no suggestion black holes create energy or a nearby 'positive energy/density region' which would violate conservation laws. As I've mentioned before, there is a convention on this site that it should be possible to follow posts without going offsite. I'm certainly not going to read section 3 to try and guess its relevance.

To save me reading through your entire reference, please quote the claim that accretion discs must exist whether or not matter is falling towards the black hole. You seem to be claiming that black holes create positive gravitational energy and some of this creates gravity waves during mergers. You're ignoring my post #15, particularly the last line. AFAIK no one is missing that fact.

I don't think using the Schwartzchild radius of a BH as a reference for gravitational potential is helpful here. You may not intend this, but you seem to be suggesting that masses cause nearby spacetime ( and matter ) to have greater energy than distant spacetime ( and matter ) while the usual idea is that on average the mass-energy of matter etc is exactly or nearly equal to its negative gravitational mass-energy. An analogy for the local high energy of an accretion disk would be an Apollo capsule flying through the atmosphere at 25000 knots after falling from the moon. Locally, a vast amount of kinetic energy seems to have been created from nothing; the simplest way to avoid this is to say that the capsule's increased kinetic energy is balanced by its decreased gravitational energy. If a BH created a nearby positive energy/density region that energy would be absorbed by the BH causing exponential mass-energy creation.