Space rocket engines performance and technology: SSME vs. RD-0120

Question: Between this two LH2/LOX rocket engines the SSME(RS-25 different) of the Space Shuttle rocket and RD-0120 of the Energia rocket, which one has higher performance and better technology to launch space rockets in low earth orbit?
Comment: Beyond fun and games, why?
Comment: it is about which rocket engine has better technology for launching payload to low earth orbit
Comment: I was trying to know if it is kind of formula to calculate the performance of engines by knowing elements such as the thrust in sea level and vacuum, specific impulse in sea level and vacuum, burning time, gross weight of the rocket and elements of other booster stages solids or liquids in each case of the rockets.Kind of formulas for calculation such as for total impulse or for payload momentum for example.So it makes sense now.Anyway i am editing and changing the question to be more easier to answer since conclusions could be given maybe only by projectors of the rocket, engines & blueprints
Comment: Even sea level ISP of rd-0120 is lower, atmosphere is pretty thin, so first stage will benefit more of higher vacuum ISP of RD-0120 when used on real rocket.
Answer: The two big performance considerations for a liquid fueled engine are thrust and specific impulse. On these criteria, the two engines are very comparable.
The SSME has a bit more thrust: 1860kN at sea level, increasing to 2279kN in vacuum, versus RD-0120's 1526kN to 1961kN -- a 22% difference at sea level and 16% in vacuum.
The other major factor is specific impulse, which is a measure of fuel efficiency. The SSME's specific impulse is 366 seconds at sea level, increasing to 452 seconds in vacuum; the RD-0120's goes from 353 seconds to 455 seconds. RD-0120 is spending 3% more fuel per unit of thrust during takeoff.
So, once out of atmosphere, the Russian engine is almost 1% more efficient; in all other cases, the SSME outperforms it.
If you swapped the engines between Energia and the shuttle -- keeping the number of engines the same, so 3 RD-0120 on the shuttle and 4 SSME on the Energia -- the re-engined Energia would be able to lift a little more payload, and the shuttle could only make it to orbit with a reduced payload -- about 15 tons instead of 25.
The shuttle would still be able to take off despite the reduction in thrust, because at liftoff the solid rocket boosters are doing most of the work. It would ascend a little more slowly at the start, which would cost a little more fuel due to gravity losses, but it turns out that the shuttle throttles its engines down substantially over the course of the ascent to reduce aerodynamic loads and peak g-forces, so the RD-0120s would have more than enough power during much of the ascent.
Its slight edge in performance doesn't necessarily make the SSME "better technology". It's one of the most complicated and expensive rocket engines ever flown. RD-0120 gives you more bang for the buck (or maybe "more rumble for the ruble").

Here's a method to roughly estimate the payload hit. Ignore the SRBs for the moment and consider a 68 ton orbiter, 25 ton payload, 30 ton external tank, and 730 tons of propellant: 853 tons total, 123 tons with propellant expended. Apply the rocket equation with the 366 second sea level SSME figure:
$$∆v = 366s \cdot 9.81m/s^2 \cdot \ln \frac{853}{123} = 6953 m/s$$
Now determine the change in payload mass (∆m) needed to get the same result from the RD-0120's specific impulse:
$$6953 m/s = 353s \cdot 9.81m/s^2 \cdot \ln \frac{853+∆m}{123+∆m}$$
$$ 7.447 = \frac{853+∆m}{123+∆m} $$
Rearranging and solving, we get:
$$ ∆m = -9.77 $$
So if the sea level specific impulse held throughout the flight, and the SRBs weren't involved, shaving 9.77 tons off the payload would produce the same ∆v. This is a worst case because we expect the specific impulse of the RD-0120 to "catch up" with and even exceed that of the SSME over the course of the flight, so the actual payload hit should be smaller -- but we'll also lose some ∆v to gravity during the slightly slower ascent, so 10 tons is a reasonable estimate.
You can run similar calculations on the Energia side to work out the additional payload mass it could lift if equipped with SSMEs, but I can't find clear numbers for its dry, wet, and payload masses; probably it's a fairly similar delta.
Comment: I had to vote you up just for "more rumble for the ruble."
Comment: Of course, the SSME was reusable, which might well explain your point "one of the most complicated and expensive rocket engines ever flown"
Comment: Great answer. Further to one of your points it says here https://en.wikipedia.org/wiki/RD-0120 "The RD-0120 achieved nearly identical specific impulse and combustion chamber pressure with reduced complexity and cost, as compared to the SSME, primarily at the expense of lower thrust-to-weight ratio." ......"Some of the Russian design features, such as the simpler and cheaper channel wall nozzles, were evaluated by Rocketdyne for possible upgrades to the SSME. It achieved combustion stability without the acoustic resonance chambers that the SSME required."
Comment: Running the comparison at sealevel ISP is not realistic, as a launching rocket spends less than the first 2 minutes in significant atmosphere, the next 6.5 minutes are in vacuum or very very low pressure air.  Applying the same calc as the answer in vacuum, gives the rd0120 a 2.3 tonne ADVANTAGE, even including the extra 0.6 tonne dry mass due to engine mass difference. Assuming the first 2 minutes is sealevel and rest vacuum, puts the balance at: 0.39% advantage to rs25, mostly because of increased dry mass going to orbit. (this does not account for increased gravity loss due to reduced TWR )


Presheaves on a complete Segal space

Question: Let C be an $(\infty,1)$-category, incarnated as a complete Segal space, hence in particular a bisimplicial set.  Is there a model structure on the slice category of bisimplicial sets over C which presents the $(\infty,1)$-presheaf category of C?  Ideally, such a model structure would be Quillen equivalent to the contravariant model structure over a quasicategory incarnation of C, and to the projective model structure for simplicial presheaves on a simplicial-category incarnation of C.
Answer: Yes.  Let $W$ be a complete Segal space, thought of as a simplicial "space" $(W_q)$.  The fibrant objects of your model category will be the fibrations $f:X\to W$ such that for each simplicial operator $\delta:[q]\to [p]$ with $\delta(q)=p$, the evident map from $X_p$ to the pullback of
$$X_q \xrightarrow{f} W_q \xleftarrow{\delta} W_p$$
is a weak equivalence of spaces.  (Edit: in fact, it suffices to require the evident map to the pullback to be a weak equivalence only for $\delta:[0]\to[p]$ with $\delta(0)=p$.)
I worked out some of this years ago, but never finished it; somebody should do this (or perhaps someone has already?).  Lurie has done pretty much exactly the same thing in the context of quasi-categories, in HTT.
Comment: Thanks!  Two questions.  (1) By "fibrations $f\colon X\to W$", do you mean Reedy fibrations?  Or fibrations in the CSS model structure?  (2) Is the "evident map" necessarily itself a fibration (say, if $f$ is a fibration according to your answer to (1))?
Comment: Also, (3) I presume that this model structure is constructed as a localization of some over-model-structure for simplicial spaces over W?  And (4, I guess) does that imply that the weak equivalences between fibrant objects in this model structure are still just the levelwise equivalences?
Comment: (1) I mean Reedy fibration.  It turns out that if W is a CSS, and f is a Reedy fibration with the above property, then X is also a CSS, and thus f (being a Reedy fibration between CSS's) is also a fibration in the CSS model category.  (2) I believe it is a fibration if $\delta$ is injective, but not generally.  (In the condition describing fibrant objects, it actually suffices to require a weak equivalence only in the case $\delta:[0]\to [p]$.) (3) Yup.  (4) Yup.
Comment: Beautiful!  That's all I could have hoped for.  Someone should really work all of this out and write it up.

Presheaves on a complete Segal space


Why did reanimated Itachi lose eye vision after using Izanami?

Question: As I understand, any physical part of a reanimated person cannot be destroyed. It will be regenerated automatically within a short time. Then, why did Itachi lose his eyesight after using Izanami? He should've got the eye back quickly as he was a reanimated person. Or, he could've damaged his own eye with a kunai, so that he would get a fresh Mangekyo Sharingan.
Answer:
Q. Any physical part of a reanimated person cannot be destroyed.

The eye was not destroyed at all. It just lost its light forever. As stated in the wiki (emphasis mine)

It is a genjutsu which affects the target through physical sensations shared between them and the user. Like its counterpart, in exchange for the temporary ability that it grants the user, the Sharingan with which Izanami is cast is rendered blind and loses its light forever.

Q. It will be regenerated automatically within a short time.

Since the eye was never destroyed, it did not regenerate.

Q. He could've damaged his own eye with a kunai, so that he would get a fresh Mangekyo Sharingan.

The light of the eye was already lost. Even if Itachi were to destroy it with his own kunai, the regenerated eye would still have been the one without its light.
Also, it should be noted that Itachi did not want to stay in the living world anymore, as he had no more attachments with the living (after telling the truth to Sasuke). Therefore, Itachi would never have tried it at all in the first place.
Comment: He'll get the eye back, but it would be without light. Since the eye has already lost its light, the light would not come back. The eye would, however, re-generate, just like all the other body parts.
Comment: Here is a scenario, What if itachi is blasted into pieces by a paper bomb? Will he get Sharingan back along with his other body parts?
Comment: One last question, is losing eye light not physical damage? like nerve disconnection
Comment: Not always. Let me just quote few lines about vision loss from wikipedia. *Vision loss or visual loss is the absence of vision where it existed before, which can happen either acutely (i.e abruptly) or chronically (i.e over a long period of time). It may be caused by media opacities, retinal disease, optic nerve disease, visual pathway disorders, or functional disorders, or it may be in fact an acute discovery of chronic visual loss.* Thus you can becomes blind by either damaging the retina or something and because of using Izanami as well! :P
Answer: The effect of using Izanami is that you lose use of an eye - that is, the user becomes blind.
The eye is there - it has not been lost. Itachi is simply now blind in that eye.


Cisco 1800 series: sys-2-chunkexpanfail: error every time

Question:
My knowledge of Cisco is very basic and I´m having this error constantly. I have to reboot every time, and it does not seem right. How can I solve it at once?? What I know of this device is that it has set up a VPN account and other Internet whenever I get the error Internet connection is cut, but not the VPN.
Comment: Please don't use pictures for text in your question or an answer. Copy the text and paste it into your question.
Comment: Are you able to do a "#show proc mem" command? It appears your router has run out of available memory space or you have hit a bug. I would wager a restart would stop this error temporarily but after a while, you will hit the same problem again.
Comment: Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
Answer: If you are on release 12.4(15)T12 | 12.4(24)T2 then this could be related to a Cisco bug CSCtg26917 with more details on it here
Symptom:

Chunk manager consume almost all memory. We found the issue is related
  to NAT

Conditions:

The memory hold by chunk manager increased quickly while NAT translate
  increased rapidly.

If you are using NAT and are on this version of IOS, it would be adviseable for you to do an upgrade of the firmware.
Answer: Cisco 1800 Series Integrated Services Routers Fixed Configuration Models

The default memory of 32 MB Flash and 128 MB DRAM is sufficient to
support complex configurations and help ensure operation for an
extended period. Memory is expandable to support maximum of 128 MB
Flash and 384 MB DRAM, offering additional investment protection.

Portable Product Sheets – Routing Performance


Why are plasmid genes not already incorporated into bacterial chromosomes if necessary for stressful situations?

Question: If plasmids are important for bacteria to express specific genes under stressful conditions, why are these genes not already incorporated into their chromosome to begin with? What is the evolutionary significance for this?
Answer: Plasmids do have the advantage that they replicate independently of the cells chromosome and that they can be transferred between different bacteria. This spreads the gene encoded by the plasmid to other bacteria, which then can also survive.
Think about antibiotic resistance. Bacteria which have a plasmid which allows protection against the antibiotic will survive. They can transfer this protection to other bacteria which then also become resistant. This can either happen through pili which develop between bacteria or also via the uptake of plasmid DNA from the environment in a process called horizontal gene transfer.
Additionally mutations on the plasmids are not as dangerous on the plasmids than on the chromosomal DNA, where essential genes might be damaged. Plasmids can also get lost, if they are not needed by the bacteria due to a missing selection pressure, which is also much harder for genes encoded on the chromosome.
Comment: Thank you. Would you mind clarifying on how exactly they get "lost"? Do the plasmids still remain inside the bacteria or do they get transferred when unneeded?
Comment: I am not sure, if the exact mechanism is known, but I can look into it.
Comment: How many copies of a plasmid get made can vary, and then how those plasmids segregate into each daughter after mitosis can vary. It is possible for one of the daughters to wind up with no copies of a plasmid. If that is the cell you or evolution picks to replicate, the plasmid is lost in all descendants.


Is OpenBSD's low number of exploits really that relevant?

Question: The number of OpenBSD's known vulnerabilities is tiny, but so it's the number of users. How significant is this scarceness of exploits found?
Comment: You use applications with OpenBSD. How many vulnerabilities do they have? How many features do they have (compared to other OSs)? Maybe you should look at the bigger picture.
Comment: It's not so much the number of users that affects OpenBSD's security as a restricted set of base software and paranoid default configuration.
Comment: People that use highly secure software don't often go blabbing about which software they use...
Answer: Yes, it's relevant, but you have to understand the context.
There are several ways a platform can achieve a low rate of exploitation such as code quality, a hardened configuration, a limited feature set, and obscurity. There's no doubt that OpenBSD benefits from obscurity to some degree - if it were as popular as Linux or Windows, many more people would be scrutinizing it. However, it's had so few exploitable flaws over time that you can't simply write off it's track record as obscurity alone. Other platforms of a similar size usually contain many more exploitable bugs.
OpenBSD has consistently emphasized code quality over features, and has always minimized the number of services listening by default, so there just isn't much attack surface. It's a minimalist OS compared to Linux and Windows, so it's really a different animal.
Answer: OpenBSD has plenty of issues against the base system (see their patches section), past and present.  It is not an obscure OS - it is exceedingly well documented, and very popular with people who build infrastructure. And others. But I suppose the text install program puts people off.
It is my understanding that its standard services (not ports) are particularly hardened against remote exploitation (now with pledge and nowxallowed, before that a number of other measures, not just privsep and chroot).
It doesn't include a ton of weird software into userland by default, and that is one reason there are so few exploits against it.
Also there is the perhaps unique feature of /etc/malloc.conf, which enabled an operator to preempt misbehaving programs.
OpenBSD isn't into 'rapid growth at any cost'. The core kernel developers are not quite as hopping mad as Linus Torvalds, who has himself admitted that things are being submitted to the Linux kernel, that even he does not understand - although he can veto submissions, what good is that if he blindly accepts contributions?
The code base of OpenBSD is not particularly small, but kept terse and readable, and often tedu'ed (trimmed). Anyone can read it and understand enough to make it worthwhile.


OpenGL desktop driver

Question: I have RPi3 with 7" touchscreen display connected, Raspbian Stretch installed.
I would like to use OpenGL desktop driver. I run "raspi-config" > Advanced Options > GL Driver and select the driver. But the problem is that it does not work.
GL (Full KMS) - connected touchscreen does not display anything, only external HDMI display works
GL (Fake KMS) - connected touchscreen works, although the initial output is a little but delayed (e.g. rainbow image is not visible). The output begins shortly before displaying Plymouth splash.
But in both cases, the Xserver does not start at all. It ends up with the error:
(EE) parse_vt_settings: Cannot open /dev/tty0 (Permission denied)
When I modify /etc/X11/xinit/xserverrc to use different terminal, I get error "Cannot open virtual console 1 (Permission denied)"
Is there any solution to make OpenGL driver fully work with touchscreen and Xserver?
Comment: Is Raspbian Stretch fully updated? What power supply are you using? Do you ever see the lightning bolt icon?
Comment: Yes, fully updated. We have the official RPi power supply and don't see any bolt icon. Everything else works correctly...
Answer: The "(EE) parse_vt_settings: Cannot open /dev/tty0 (Permission denied)" problem was solved by adding needs_root_rights=yes into /etc/X11/Xwrapper.config
Now Xserver starts correctly but the load is much slower with GL driver.
This solution does not fix no-touchscreen problem with GL Full KMS driver.

OpenGL desktop driver


Are there any tabletop apps to allow you to play warhammer 40k with friends in other cities?

Question: Pretty much as the title; I've looked at vassal 40k, but it hasn't been updated in a while and is missing units. I'm not necessarily looking for something for WH40k in specific - as long as it allows for moving units, measuring distances, and custom sprites/enough sprites to use "counts as" we should be fine.
Answer: As @Skeith mentioned, Games Workshop LLC is very vicious when it comes to protecting their Intellectual Property license, so it will be very hard to find anything designed for this on purpose.
That being said, Steam recently released a game called Tabletop Simulator, which, with a lot of work, could probably be used as a tool for this (right up until GW catches on and their lawyers destroy the life of whoever is supporting the mod).
Comment: I believe there are a lot of "customize me"-simulators out there. They all have in common, that every action needs several clicks and agreement from other players.
Answer: Gw are famous for taking legal action against anyone and anything that uses its IP without license.
Vassal were the last to try what you are asking and i believe were shut down with a cease and desist.
Sadly anything close to what your seeking would be shut down quickly by GW. This means no one is making any such software.
Comment: GW can't touch Vassal. It's a generic engine for any game. They can make it difficult to host a 40K module, but they can't actually get it pulled down anymore if the hoster does it right. I've posted current information in a separate answer.
Answer: The closest program that I can suggest for doing this is with Tabletop Simulator. It is a program on Steam that is a physics engine with a wide variety of pre-loaded boardgames and tens of tools that allow you to emulate virtually any table-top game imaginable. In fact, the game has it's own Workshop application that has tens of thousands of games, sets and models to choose from, including some from WH40k...
Answer: You could use roll20.net
Whilst geared towards RPG,  it does come with a tabletop with grids or hexes,  you can define the size of each grid,  u can place custom tokens and what not,  but you would need to do a lot of the prep work yourself in terms of uploading images for the units and preparing the map
Answer: I know this sounds simple and slightly low-tech, but setting up a board with proxied models and emailing turns is always a good way to play. I am working on something to simulate games, and am going to try and get it published with Games Workshop, but even if that does work, it won't be as good as actually having the table set up in front of you.
Answer: VASSAL works and there is a 40K module for 7th edition.
https://www.reddit.com/r/Vassal40k/


Reaction due to gravity

Question: There is a reaction to the gravity of the earth on us but the earth does not move due to its huge mass. But what if I combine the weight of all humans and other things on Earth? Is it not enough to move the earth from its position(even a bit)? What if (imagine) the bio population suddenly increases? I think that we are not being taught the complete thing in school$(a\propto\frac{1}{m}$, when $F$ is constant). Is there anything more to gravity than just this?Please explain.
Comment: Essentially a duplicate of  http://physics.stackexchange.com/q/70732/2451, http://physics.stackexchange.com/q/56245/2451 and links therein.
Answer: According to Google the mass of the earth is around $5.972 \times 10^{24}$ kg (presumably that figure includes its 7 billion human inhabitants plus everything else were meant to be sharing with). If we take the average weight for a human as given by WolframAlpha as 62 kg this gives humanity a combined weight of $4.34 \times 10^{11}$ kg - so our share in the distribution of mass in/on the planet is approximately only 1 part in $1.4 \times 10^{13}$!
Now while in theory if we shipped everyone on the planet to one of the poles and then got them all to jump at EXACTLY the same time there would be a minute blip on the position of the earth in relation to where it's normal trajectory would take it, we would all resume the same course once everyone's feet touched ground again.... As to how big this 'blip' would be - I doubt it is worth the time of calculating it (unless somebody else reading this is bored).
As for if the bio-population were to increase this would have no effect since until we start breading people in space the population will always be just a minute fraction of the relatively fixed mass of the planet (the mass of the planet as a relatively closed system [incoming space dust and outgoing atmosphere] isn't effected no matter how many of it's constituent rocks are transformed into other arrangements that just happen to breath).
And finally, as to

I think that we are not being taught the complete thing in school

You are 100% correct! What we get taught in school is always a simplification due to necessity considering that any one branch of enquiry is usually more than enough to keep multiple humans busy for there entire academic career.
Comment: Also note that the earth is a (for most purposes) closed system, so having more people by breeding simply redistributes the weight.
Answer:
Is it not enough to move the earth from its position (even a bit)?

For all practical purposes, nope. Think of it in the following manner:
The (Earth + All the Humans) can be viewed as one system, and in this case, the gravitational force exchanged between any one person (e.g. you), and the Earth, is an internal force of this system. And internal forces can not produce a net motion of the center of mass of a composite system, since they will always cancel in pairs, and therefore, make no difference to center-of-mass. The argument can be generalized to include N other human beings, even with this, the internal forces can not make a net difference to the situation. And of course, if you feed in the numbers, the center of mass of the (Earth + All Humans) system, will more or less be at the center of the Earth, due to its large mass ($6 \times 10^{24}$kg). In comparison, the world population is about 7.2 billion, and if one ascribes an average weight of 80 kg to each, it is still lesser by orders of magnitude. And of course, the 7.2 billion are distributed (inhomogeneously) over the entire world, an not concentrated as a bunch. Thus, for all practical purposes, the center of mass is the center of the Earth.
Comment: Do you mean that as there is no net external unbalanced force in this system?
Comment: @tatan - ... due to the gravitational interaction between the particles making up the system - no. _External_ forces, like the gravitational attraction of the moon, shall produce a net motion of the CM of this Earth+Humans system, but the forces exchanged between the particles making up the system are internal forces, and they can't.

Reaction due to gravity


How to stop Windows firewall from blocking Bonjour hostname resolution

Question: I have Bonjour installed on my Windows 7 PC, and the installer appears to have poked all the necessary holes in the Windows firewall. However, I can't ping windows-pc.local from my Mac. If I completely disable the Windows firewall, I can. How do I configure Windows firewall to allow Bonjour hostname resolution?
Answer: Create a new Inbound Rule that allows traffic over UDP port 5353 in the needed security zones.
Step-by-step:

Open Windows Firewall Advanced Settings

Create a new rule in Inbound Rules

Under Protocols and Rules, choose Protocol Type > UDP and Specific Ports > 5353

Choose the appropriate security zones for your network. For more information on security zones, read the Microsoft documentation: How Windows Firewall with Advanced Security Works
Comment: And how would you do that specifically?
Comment: @patrix I updated the answer with some better documentation.
Comment: Nice indeed____.


How did the first words arise?

Question: As far as I know linguists consider language arbitrary. If so, how does etymology work? We have a word and we trace it back to its origins. Then, we find that it either comes from a different language or originated at a certain time. But then what? We have no idea how the word originated originally or why it came to mean what it does. So do we have any idea how or why any word came to mean what it does, originally? And if not, because language is arbitrary, then words got their meanings by someone just deciding a certain sound would represent a certain meaning and people went along with it?
Comment: I think your question is a bit too wide here. What exactly is it that you want to know? Please consider 1) making it more specific or 2) split it into a series of questions, it's ok.
Comment: I agree with @LouisRhys. Your question addresses a very broad topic. As written in the [FAQ]: "_Your questions should be reasonably scoped. If you can imagine an **entire book** that answers your question, you're asking too much._"
Answer: Language is arbitrary as you say but it is also not created by authority. There's no one person or committee saying: "Let's start a new language, and we'll call all those four legged things we ride 'horse'" (except for the wildly out of the ordinary constructed languages like Esperanto).
There are all sorts of theories about the true, way-back-when, something-out-of-nothing origins of words and syntax, but they're all very speculative and quasi-scientific (no one is there to record the early language speakers). Looking at the behavior of other communicating animals (dolphins/whales, birds) gives ideas, but tends to the "Gosh we think it could have been like this, maybe."
A grunt here, a sigh there, eventually people, out of arbitrary association with other activities, modified and distinguished these sounds, not through any dedicated process or choice, created words associated with meaning. Well, that's a theory with little support other than plausible analogy.
Answer: I think I might understand what you are trying to ask in your question. Basically, you want to know whether there is a point where etymologists have to stop because you can't go further. (?)
Remember that when linguists try to reconstruct forms (proto-Germanic, proto-IE etc.), they say nothing why a cow is "a cow". In most cases, the connection between form and meaning is purely arbitrary. Historical linguists study how words (and other linguistic units) change and why. They don't explain why those words have a particular form.
cf. Jespersen's remark that "the earliest accessible stage remains unexplained and must be taken as it is" (Jespersen, 1924/1992, The philosophy of grammar, p. 81).
Answer: We know exactly how the first words arise, at least in the case of signed languages.  Gestural communication is systematized to create  homesign,  which then may be reorganized and grammaticalized to create conventional language. The process is described in detail in:
Goldin-Meadow, S. (2003) The resilience of language: What gesture creation in deaf children can tell us about how all children learn language. New York: Psychology Press.
Answer: First words can be defined both ontogenetically and phylogenetically, correspondingly, this is the research topic of both language acquisition and language evolution. (the division of labor of the same research topic does not mean the two fields are not closely tied!)
There are several good books to start with:
Michael Tomasello. (2008) Origins of Human Communication. MIT Press.
Morten H. Christiansen, Simon Kirby. (2003) Language Evolution. Oxford University Press.
The books above both, more or less, deal with the arbitrariness of sign. Also there are some relevant papers:
The Origins of Arbitrariness in Language. Michael Gasser. Proceedings of the Annual Conference of the Cognitive Science Society (2004) Volume: 26, Publisher: LAWRENCE ERLBAUM ASSOC PUBL, 10 INDUSTRIAL AVE, MAHWAH, NJ 07430 USA, Pages: 4–7
The arbitrariness of the sign: Learning advantages from the structure of the vocabulary. Monaghan, Padraic; Christiansen, Morten H.; Fitneva, Stanka A. Journal of Experimental Psychology: General, Vol 140(3), Aug 2011, 325-347. doi: 10.1037/a0022924
Answer: It's quite possible we'll never know. Words don't leave fossils, and writing is a very new occurrence in the great scheme of things.
If I recall correctly, the absolute limit assumed for finding shared etymological origin is around 10,000 years. Of course, that number is arbitrary, but it gives you a ball-park idea of how far back we can expect to reliably recognize traces of similarity.

How did the first words arise?


Can Facebook Messenger read screen contents?

Question: The Facebook Messenger offers this nice little feature called 'chat heads'. For that, it requests the permission to overlay everything. However, i read somewhere about the fact, that it can also see what is displayed on the screen. Can you tell me if that is true?
Comment: I think, but I won't post an answer as I'm not sure it call tell what application is running on the screen but not see the screen itself. I.e. it can see that Nova Launcer is running, or Angry Birds and overlay it, but not actually see your game, or your launcher screens etc.
Answer: The "draw over other apps" permission (known to developers as android.permission.SYSTEM_ALERT_WINDOW) only lets the app create a window of type TYPE_SYSTEM_ALERT. This is the same type of window used by the battery warning, amongst other things, and is shown on top of any normal window, whatever you're doing.
Drawing this window on top of the other windows is done by Android itself. An app with this permission still can't read other parts of the screen or read other apps' data. This permission doesn't even let the app see (the names of) what other apps are running, which is controlled by a different permission called, "Retrieve running apps". Facebook Messenger doesn't use that permission, but the main Facebook app does, in order to support Facebook Home.
Even so, this permission is far from harmless. An app might use this permission to display pop-up ads when you're doing something else: ads that you can't dismiss, not even by pressing home. With a bit of cunning, it might even be possible for an app to place a window that conceals an important confirmation dialog, so that while you think you're answering "Yes" to a harmless question, the button belongs to a warning about installing further apps or deleting your data, which the system alert has hidden. This was a common tactic used by Windows malware a few years ago (before UAC arrived in Windows Vista).
Comment: This definitely helped out, and makes me feel a lot better. Sadly i don't have the reputation for an upvote yet, will do that once i have the reputation. Also, thats why you read permissions list before installing an app :)


Minimum age on Stack Overflow

Question: I am a young person and I want to know what is the minimum age for Stack Overflow users, because if I type in my true age I don't want to be deleted or blocked from Stack Overflow due to my age.
Comment: Okay, this isn't a literal duplicate, but the older question solidly provides the answer to this one and gets to the real issue.
Answer: You must be 13 to participate on the Stack Exchange network.
This is outlined in the Terms of Service, under the section titled "Access to the Service," which says:

Subscriber certifies to Stack Exchange that Subscriber is an
  individual (i.e., not a corporate entity) at least 13 years of age. No
  one under the age of 13 may provide any personal information to or on
  Stack Exchange (including, for example, a name, address, telephone
  number or email address).

The age 13 requirement comes from the Children's Online Privacy Protection Act of 1998 (COPPA), a United States federal law that details what a website operator must include in a privacy policy, when and how to seek verifiable consent from a parent or guardian, and what responsibilities an operator has to protect children's privacy and safety online including restrictions on the marketing to those under 13.
While children under 13 can legally give out personal information with their parents' permission, many websites just disallow underage children from using their services due to the amount of work involved.
See Also
Children's Online Privacy Protection Act
Comment: You can participate under the age of 13 so long as you don't provide your own person information.
Comment: @Servy Which means as an anonymous user, which isn't any fun.
Comment: @Undo, Not exclusively.  It has been explicitly stated that if your parent creates an account for you, with their email, you can use that account, regardless of your age, as per my answer.
Comment: @Servy Ahh - weird laws are getting weirder.
Comment: See [this related post](http://meta.stackexchange.com/a/102250/186381) for why this answer is incorrect.
Comment: If you guys think every user here has provided true information, you need to look at more profiles.  I'm sure a fair percentage are anonymous in some way; either providing false names, locations or ages.
Answer: You are not allowed to provide your own personal information if you are under the age of 13 (most notably your email, which is needed to create an account).  If your parent/guardian uses their personal information to set up an account for you, regardless of your age, then you can use the site.
See this related answer for more information
Comment: In all fairness to Adam Davis and his eloquent answer on the other question, he's not a representative of Stack Exchange, and can't really speak for them.  The Terms of Service don't say "get your parent's permission," they say "you must be 13."
Comment: @Asad: that sentence is not violated if you don't provide any personal information. The *previous* sentence where you must certify that you are at least 13 is violated instead.
Comment: Not sure about the downvote...
Comment: @Undo: Really, you just have to know how to read.
Comment: @RobertHarvey [...] to create an account or provide personal information.  Which means, so long as you don't do either of those things then you are not in violation of the ToS.  He is merely indicating that if you follow the instructions he provided you are in compliance with the ToS and US laws.  If the ToS is changed to be stricter, then your answer may become correct.
Comment: Under that interpretation, entire dorms could share a single account, which is almost certainly not the desired outcome, since the TOS clearly states that you must be an *individual.*  The TOS clearly defines the term "Subscriber" as *the person accessing the services.*
Comment: It's quite fun watching programmers talk law, actually :D
Comment: @RobertHarvey Yes, but it is possible for the Subscriber (the one who accesses the services, not necessarily the person who provides personal information and registers the account) to be a single individual under 13 years of age. This clause: *"No one under the age of 13 may provide any personal information to or on Stack Exchange (including, for example, a name, address, telephone number or email address)"* is not violated by the sole user (and not creator) of the account being under 13. I may be entirely wrong, of course, since I have little understanding of legalese.
Comment: @Wooble Yes, that's true.
Comment: @Servy I found a hole in the argument about parents providing info in place of their child's: "Subject to the terms and conditions of this Agreement, Stack Exchange may offer to provide the Services, as described more fully on the Network, and which are selected by Subscriber, **solely for Subscriber's own use, and not for the use or benefit of any third party.**"

Minimum age on Stack Overflow


Upload document dialog box trimmed

Question: For a particular document library in SP 2013 when i try to upload documents, the dialog box to enter the properties is hidden/trimmed. What can be the issue?
Answer: Form fields may be hidden in EditForm.aspx of library. Navigate to EditForm.aspx page and append your item ID
For example https://your site Url/libary name/Forms/EditForm.aspx?ID=Item ID
Edit that page and see if there is any script editor/content editor web part added to hide fields.
Another way is with the help of SharePoint designer. Open a particular library, in that you can see the edit form.aspx and then check any code added to hide.
Answer: It could be the configuration of the columns in the list.  Are you able to provide a screenshot of the columns that you expect to add?  Are they hidden perhaps (do they show as hidden against the relevant content type in the UI, or they may be hidden in code)?

Upload document dialog box trimmed


The interaction between strings and woodwinds in an orchestral setting

Question: I have only worked with relatively small orchestras, and in that time, one of the biggest problems is the combination of strings and woodwinds, especially in contrapuntal writing where the main voice is alternating between instruments. The woodwind section always seems to stand out, even if the strings are in a higher register, which can sometimes be a blessing, but is often a problem. In the exposition of the 1st mvt of my first symphony(pretty small orchestra, have written short orchestral pieces but this is the first that I intend to exceed 10 minutes) the first and 2nd themes are stated together in the mid string section, and those 2 themes are stated with different instrumentation 3 more times, and on the 2nd time the first theme is stated by the oboes and flutes, and the 2nd by the cellos and violas both in their high register. But this is the problem. These themes are supposed to collaborate, with the first theme being the more important theme at the beginning with the second as a supportive role, but the roles switch in the 2nd and 3rd phrase. But in this statement of the first 2 themes, the 1st theme, in all 3 phrases, dominates over the 2nd, with the 2nd playing as a supportive role. What should be done about this specifically, and overall, how do strings and winds interact in an orchestra?
Comment: Rimsky-Korsakov wrote a book about orchestration that is now public domain, so it can be downloaded for free and it will help you with this. One brief thing I can say is that 2 of each woodwind can stand up to more than ten of each strings instruments, due to acoustics.
Comment: If you're working with a chamber orchestra, it might be nice to study pieces written explicitly for small forces rather than a symphony orchestra. I'm thinking Stravinsky's *Histoire du soldat*, and Copland's *Appalachian Spring* [in its original 13-piece orchestration](https://youtu.be/0LAy-wdO0cQ).
Answer: Have you ever studied some orchestration manual? They may give you insights and tools to fix this. Korsakov, Casella, Blatter, Adler, Strauss & Berlioz, Thomas Goss... there's plenty of books on this topic. Orchestration can sometimes be seen as mix of problem-solving skills and colorize by numbers, but itself is an art form.
Said this, let's address your issue. As I can imagine due your given description, you're dealing with problems of balance and proper layering (front ground, middle ground and background). Although I cannot say much without seeing/listening to the score, maybe you can start to solve this thinking in your doublings and layers' textures. The front must have a feature to stand out in front of other layers (obviously), and this is usually a compositional problem, not an orchestration/arranging one.
Check doublings minding each sounding register of each individual instrument, chord voicings, counterpoint and general texture. If it's all ok in a non-orchestrated draft, expand this thinking in layers before everything else.
Each of these books have chapters on dealing with lack of balance and stability, and plenty exercises. Maybe you could profit practicing one or another.


Linux testing - CPU & disk

Question: I am a bit rusty lately. What is the standard way to test CPU and disk I/O these days?
Answer: There are many tools out there that perform stress testing.
For Linux a easy to use one is stress: http://weather.ou.edu/~apw/projects/stress/
Answer: for the disk: bonnie++. not your most trendy benchmarking tool but one that gives useful results [ random and sequential reads/writes, i/o per sec ].
Answer: One test I do is compile the kernel. Maybe prime. Also I'm refering to this list quite a lot lately as I am testing a lot of VM configurations.
http://www.overclockers.com/forums/showthread.php?t=486495
As for "standard", I'm not sure there is one. What I think you might want to do is create a set of tests that are standard for you and apply that to your variations.
Answer: I still continue to use the old^H^H^Hclassic standbys for disk performance testing:  Iozone and iometer.  Iozone is fairly easy to get going, while Iometer can be configured to more closely match your real-life load characteristics (assuming you know what they are, of course).  I believe both are available on multiple platforms, including Linux and Windows.

Linux testing - CPU & disk


Ac unit set on 74

Question: My central air is set at 74. Yesterday and today, the house was up to 80. It has been very hot outside(90). Would this affect my ac unit?
Comment: [Air Conditioner Can't Keep up](http://diy.stackexchange.com/questions/69423/air-conditioner-cant-keep-up#comment95400_69423)
Comment: Is the outdoor unit running?  Touch the pipes that are connected to the unit with your hand.  One (smaller) should be warm, the other (larger) should be cool and possibly wet.  My first guess would be low refrigerant due to a leak.  An HVAC technician will be able to test for low refrigerant.
Comment: Are you asking if extreme heat will make it more difficult to cool your home, or if the heat will damage the AC system itself?
Comment: I know old post - but yes outside temp does affect the unit efficiency and hence ability to cool - if it is 120-130 degrees out the efficiency drops big time. However in your situation your AC unit has an issue that needs to be checked out. No one can give you a magic bullet answer with out details as there are lots of reasons it might not work correctly if it ever did.
Answer: Assuming the question is why can't your AC keep your home cooler, there are several possibilities:

The AC is low on refrigerant, look for a temperature difference of 14-20°F between the return and vents to see if the unit is cooling efficiently. If you're low, you will likely need to call a professional to pressurize the system and check for any leaks.
Dirty air filters. These should be changed at least twice a year depending on the air quality, though many manufacturers will suggest monthly.
Frozen coils. This is a sign of low refrigerant pressure, dirty filters, running the AC when it's too cold out, or having an AC that's over-sized for the home. When this happens, airflow will stop, and you'll need to turnoff the AC to defrost the coils and correct the cause.
Insufficient insulation, especially in the attic or older single pane windows. I would look for problem areas using an IR thermometer. If you add insulation on top of existing insulation, make sure you don't have two vapor barriers (craft paper backing on the fiberglass rolls) and consider installing it perpendicular to the existing insulation to minimize gaps.
Insufficient weather stripping around windows, doors, chimneys, or any other openings. Worst case you can feel these, see light showing through the crack, or notice them with the IR thermometer. But for more thorough testing, you'd have a blower installed in a door to create a vacuum and use a smoke test.

As for whether running the AC when it can't keep up with the demand will damage it, only if it's low on refrigerant since that contains a lubricating oil. When the refrigerant gets too low, the compressor will typically fail to turn on to protect from damaging itself. Otherwise it's just standard wear and tear.
Answer: iLikeDirt is wrong. If your air conditioner cannot cool your house to 74 when the outside temperature is 90, then something is wrong. Either the air conditioner is undersized or it not working properly.  You should check the air filters and air vents but you may need to call in a specialist to check the unit itself. My units have kept my house at 74 with outside temperatures over 100 and even that should not tax a properly designed unit that is operating correctly.
Comment: I think both you and @iLikeDirt are correct. It could be the AC itself, the inefficiencies of the house, or both.
Answer: Your AC unit is fine. YOU on the other hand, might be feeling a bit toasty. Looks like you need more attic insulation and a radiant barrier.

Ac unit set on 74


My ethernet and Wi-Fi are connected but, i can't seem to connect to the internet

Question: In the morning of christmas, i was browsing the internet on a Mac OSX El Capitan version 10.11 laptop. My internet connection stopped working on my laptop. That is, Ethernet and Wi-Fi simultaneously. Initially, i thought i had ISP problems. So i restarted both the laptop and the router. Still nothing in Wi-Fi and Ethernet. Yet, i discovered other people had logged in were using Wi-Fi from the same router. Also, the internet works alright in recovery mode.
Before i continue i'm using a  MacBook Pro mid-2012 version and now i'm using macOS Sierra Version 10.12. I updated hoping that that will fix the problem. It didn't. In addition, i tried using a mobile network tethering to share a connection and that didn't work as well.
Here are some methods i've used to try and fix the problem. I followed exactly  what was done here after reading this sentence on this post Now I've tried the following, in different order and a number of times, to no avail:
After running, ifconconfig en1 on the terminal. This is what i got today.
en1: flags=8823<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX> mtu 1500
    ether 2c:be:08:e6:87:3c
    nd6 options=201<PERFORMNUD,DAD>
    media: autoselect (<unknown type>)
    status: inactive

At the moment, i want to try these methods to fix the problem.

https://www.youtube.com/watch?v=RpAfpPiRSaE&t=2s
Factory reset and reinstall OS. Since the network settings will be lost

I'm thinking of doing the second one.
I hope what i've pointed out will suffice to help me solve the problem. I would really appreciate your help to solve this problem.
Regards,
Ben.
Answer: The problem came back in the same computer. The connection was restored after rerunning the Windscribe app. In addition, this app was available in both instances where my internet connection disappears. It seems that it's activity without closing it correctly caused


Entering USA with overstay in the past

Question: Maybe someone can help. I want to enter USA for 4 days. I am Canadian now. But in the past I was in the USA illegally for a period of time as another country citizen (not canadian) and my last name is different now because of marriage. Voluntarily left the country. It was 11 years ago. May I be denied the entry at the airport or what to expect ? Thanks
Comment: You can be refused entry. That said any ban you had for overstay is long over, the maximum was 10 years. But changing your name doesn't change anything. You can try and enter, you will likely not have a problem. I **recommend** you come by road so you don't have to fill any forms. If you come by air you have to fill out forms. Whatever method you choose **do not lie**. If caught that could lead to a permanent ban.
Comment: @HonoraryWorldCitizen Neither the landing card nor the kiosks ask about previous overstays. I would _not_ do this by road, but at a US preclearance airport. CBP can't be nearly as aggressive at preclearance as they can at border checkpoints. Not to say they won't, but the host country does constrain them to some extent.
Comment: Thanks. What possible questions they may ask at the entry point ? And I voluntarily left USA 11 years ago.
Comment: Of course, in case of issues at pre-clearance, OP may have to forfeit the flight (and all arrangements after that), so better pick a cheap one.
Answer: The overstay and the ban you got for it, or would have gotten if you had tried to enter again, is for you, not for the passport you have or even the name you used.
But after 11 years the actual ban is likely to be over and it should not give you problems on entering the USA.
Having had to overstay in the past may make entry into the USA harder, as there is always suspicion that you may do it again.
Living in Canada with the Canadian nationality may make a difference, as it makes it less likely that you will overstay again. If you have proof of ties to your current home, tuck them in your hand luggage or keep them handy near you if you travel by car, do not get them out before being asked for them.
There are several opinions on what is the best way to enter the USA. If you live close to an airport with preclearance you can go there and take the risk that you will not be allowed to board the flight. Using the kiosks usually means that you will not be asked questions and people with Canadian citizenship are almost always let through with few questions if any.
If you live near a land border crossing you can drive up and use that option to get into the USA.
Off course, if you are not approved for entering the USA you will have to cancel the trip and may not get anything refunded for what you have already paid. So it might be best for the first time to have a cheap plane ticket and to have your hotels in the USA booked such that you can cancel them for free, or have alike arrangements which will not cost you if you do not show up.
If you are not willing to risk either one, you can apply for a 'visa replacing' entry clearance. Your best bet for that is to go to the site of the USA embassy or consulate for your part of Canada.

Entering USA with overstay in the past


Name of the ancient law that forbade naming/publicising the name of a criminal?

Question: I think it was a Roman law, and it said that when a horrific crime was committed, the criminal could not be named, and anyone who disobeyed would suffer capital punishment. I can't remember the name, although I think it may have started with an 'H'/
Comment: The Hebew shunning law is called Herem, but it was less severe than the law described by OP.
Comment: Perhaps you are thinking of a version of Ostracism? Somehow, loosing one's name sounds more semitic (Egyptian or Hebrew) than Roman legal practice. Perhaps there was a religious connection that required annihilating somehow the offender, both in the flesh and as a person?
Answer: I believe you are thinking of Herostratus, the name of the man for whom the law was created (according to the History, he set fire to the temple of Artemis in Ephesus just in order to be famous and recorded in the History1)
More generally, that law (and other similar like those of romans, egyptians and the like) are usually called damnatio memoriae; usually they were applied against previous rulers or powerful officials who had fallen of grace, and included destroying their statues, erasing any written (or sculpted) apparition of their name.
Note: Ostracism was the name of exile. The name came because, being a severe punishment, it was usually decreed by all voting members of the polis which used ceramic pieces (ostrakas) to vote.
1: As you can see, he succeeded and the law failed.


Why is it when Goku turned Super Saiyan God Super Saiyan against Frost, it was regular yellow not blue?

Question: In the tournament between Universe 6 and Universe 7, Goku fights Frost, Frieza's good doppelganger. Goku powers up to Super Saiyan God Super Saiyan, but it is the traditional yellow instead of blue. Why is that?
Comment: The aura, the hair? Could you be more specific? Some pictures would help as well.
Answer: He turned regular Super Saiyan because he's too sympathetic. He thought Frost was a 100% good guy, making Goku think Frost deserved to win. So he purposely fought at his base Super Saiyan form. I think he thought Frost was the exact same power as Frieza and would require minimal effort. Also because the writers are leaving out a great deal of details.
Goku and Vegeta are saving their true form for the final battles.
But after Goku lost it was discovered by Jacco that Frost was cheating and exposed who he really is. Which is a bad guy. A "War Profiteer."
So Vegeta asks Piccolo to forfeit so he can fight Frost rather than Frost being disqualified. It then showed Frost's hidden weapon being removed in next episode preview. And Vegeta is a base Super Saiyan as well.
Goku wasn't Super Saiyan God 2. He was just Super Saiyan.
It all comes down to plot holes.


What is the biological basis for the perception of time?

Question: How is the "time axis" of memories encoded in the brain? I guess the time of the event could be "stored" with each event, but how is this translated into neurons etc.?
Answer: I'm no expert on the topic, but was about to find the following;
In mammals, the hippocampus region of the brain is one of only 2 regions with the capacity for lifelong neurogenesis (the creation of new neurons). This happens continuously with the creation of new memories and experiences (neurons are even created just to mark time passing - even if no memories are stored alongside - so that a perception of 10mins and 10secs is possible, even if nothing memorable happens). As new clusters of neurons are generated, they gradually differentiate and mature to become fully functional, and in this way time and memory are interlinked, and experiences are clustered together [1].
In a human study where individuals were asked to recall whether news events occurred within 1 week of each other (some related, some not), same-week and separation judgements were more far more accurate for related events. Unrelated events were essentially guesses, whereas deductions could be made about related events. [2]. This lends weight to the above argument that memories are clustered in the brain with temporal information embedded within.
The hippocampus is also involved in imaging the future. (Inconsistent) findings suggest that activation of the hippocampus allows mammals to conceive a scenario constructed from previous memories and experiences, and to store these for later use [3].
Refs

Aimone, J. B., Wiles, J., & Gage, F. H. (2006). Potential role for adult neurogenesis in the encoding of time in new memories. Nature neuroscience, 9(6), 723-7. doi:10.1038/nn1707
Friedman, W. J., & Janssen, S. M. J. (2010). Do people remember the temporal proximity of unrelated events? Memory & cognition, 38(8), 1122-36. doi:10.3758/MC.38.8.1122
Addis, D. R., & Schacter, D. L. (2011). The hippocampus and imagining the future: where do we stand? Frontiers in human neuroscience, 5, 173. doi:10.3389/fnhum.2011.00173


Bitcoin Core initialization taking forever

Question: Today is the third day, when I'm waiting for Bitcoin Core win-x64 application will sync/initialize. How long should I wait more?
Answer: Are you running the latest version? (0.12 is much faster than earlier versions) On decent PC hardware with decent internet connection it should finish well within a day, I think.
On a PC you might want to give bitcoind a bit more memory:
<code>-dbcache=<n>    Set database cache size in megabytes (4 to 16384, default: 100)
</code>


What formula is used for distance between 2 points in Google Maps?

Question: What formula is used by Google Maps for calculating the shortest distance between 2 points (having their Lat, Lng coordinates)? Is it purely based on Haversine? Or is it something different? Is there a mathematical or code implemenatation reference available somewhere?
Comment: Possible duplicate of http://stackoverflow.com/questions/1502590/calculate-distance-between-two-points-in-google-maps-v3
Answer: If Google Maps is using the great circle distance then the results are within less than 1% of the geodesic distance for the ellipsoid.
If you want to see the true ellipsoidal geodesic path in Google Maps, then visit
http://geographiclib.sourceforge.net/scripts/geod-google.html
This uses Javascript to solve the geodesic problems for an ellipsoid. Wikipedia has a lot of information on ellipsoidal geodesics; see
https://en.wikipedia.org/wiki/Geodesics_on_an_ellipsoid
Answer: According to http://www.daftlogic.com/projects-google-maps-distance-calculator.htm

You can use the Google Maps Distance Calculator to find out the distance between two or more points anywhere on the earth. In other words, the distance between A and B. Click once on the map to place the first marker and then click again to position the second marker. The mileage between the points will then be displayed. You can also build up a series of locations to find a total distance.
  An important feature of this distance calculator tool is that is "as the crow flies"...
Calculating the "As the Crow Flies" distance is a matter of using Great Circle formula.

and the Great Circle formula reference is to http://en.wikipedia.org/wiki/Great-circle_distance which does provide various computational formulas.
Answer: A straight line distance is the hypotenuse of a triangle.  This is good for distances up to 600nm.  Great Circle should be used for greater distances.
Latitude coordinates change into miles easily as one minute of latitude = 1 mile.
Longitude is a bit more difficult as the meridians of longitude converge when approaching the poles.
The formula for calculating longitude distance is: "Dep = d.long * Cos Mid.Lat"  Dep is the same thing as miles.  d.Long is the difference in longitude and expressed in minutes.  Mid.Lat the average latitude and expressed in minutes.  Then use Pythagoras to work out the hypotenuse.


What to do with a bent but not broken aluminum seat stay

Question: unfortunately I got hit by a car. I was on the main road, in the cycle way and the car had a stop sign coming out of a school. He did see me but got distracted by the kids. Anyway, I was wondering if you could help me out determine is my bike is safe to ride or I should do anything about it.
The rear fork is a bit bent but not broken and it's aluminum. It's a Cube SL bike.
Thanks in advance!
Comment: Did you get the driver's insurance details? This looks pretty damaged, so the insurance (or the driver) should be responsible for at least a new frame.
Comment: I would 100% do a police report, to get a record of the event.  Even if it leads to nothing then you have something to reference in the future if making a claim on your own insurance.
Comment: @Maco I'd also recommend removing the rear wheel and checking for a bent axle.  The left dropout doesn't look straight. You might also have problems with the rear brake disk. I'd also be in the market for a new frame.
Comment: It's work-hardened now. I'd leave it alone and adjust the wheel if necessary.
Comment: Frankly, I would attempt to straighten the stay.  Even though bending it back weakens it further, removing the bow will reduce the flex that will cause more weakening as you ride it.  I'm thinking place planks of wood on both sides and clamp, or some such.
Comment: Hi there, that's another story. Let's say he was not from a community you wanna mess with or that tend to go around with insured cars...
Answer: Aluminum alloy is weakened by being bent. The seat-stay is bowed in so that loads will tend to bend the stay more. The stay probably will not fail suddenly, but it will develop a crack where it's bent if you keep riding it.
It's probably OK to ride on temporarily, even if the stay does fail the other stay will support the wheel.
You say the bike is a Cube so presumably you are in Europe. The driver's insurance will cover the damage done to the bike, or you can sue the driver in some sort of small-claims court.
Comment: *The stay probably will not fail suddenly*  IMO the real problem is that when it does fail, there's a really good chance it takes out the rear wheel - and if that happens at speed, an "adventurous rapid reduction in velocity" will likely occur...
Comment: Thank you. There's a lot to improve regarding car insurance and road control in Ireland. The guy was a member of an outsider community. They don't get licences or insurance and there's almost no control for that. There was no scenario for me where I could have it replaced.
Comment: Regarding your comment, I'm mostly concerned about my own safety. You think this can affect the bicycle's performance or balance? Thanks again
Comment: @Maco the rear triangle must be distorted a little. As I said, it's probably ok to ride on but the frame will very likely crack. Inspect that area often.
Comment: I think I agree with @AndrewHenle. I can't confidently say the stay won't fail suddenly. We can say that damaged carbon can appear fine and later fail unexpectedly, whereas metal frames or components will tend to show obvious cracks or other damage (e.g. above) before failing. The thinner that aluminum is, the quicker it should fail. If that's a lower end bike, it may still last a while, but I agree I wouldn't ride it as I couldn't predict when it would go.
Comment: Thanks guys. Obviously not what I was hoping to read, but I guess I'll have to replace it... I'm so sad man...  Thanks again.
Answer: Safe - probably yes. Good idea - no.
As Argenti Apparatus stated, the bike should not fail without some warning, but it probably will fail sooner or later. As people noted in the comments - the geometry seems to have been changed - the wheel seems to be pointing slightly to right, the drop-out seems out of plane etc. The hub axle might be bent, also the bent drop-out may be causing extra stress on the bearing - in that case the rear hub will fail pretty soon. The bicycle will not ride straight now, and some parts will likely not work right and die much faster (shifting might be off similar to bent hanger, disc brake may act up if it is misaligned).
If you ask frame maker they will tell you the frame is busted and you have to exchange it. You could try to find someone who can bend the seat stay back into correct position and weld some piece of aluminum to strengthen the damaged part, but your mileage with this kind of hack repairs may vary. My biggest fear would be, that after some time riding new weakened areas might show up, requiring additional  welding. If you want to go that way, you should find a good bike service and ask them for recommendations - often these places know of aluminum welders (at least here, in Poland).
Also - welding aluminum (requires TIG) could be expensive and it might be cheaper to find new frame and swap everything from the old bike to new. Winter is coming™, and so you can find good deals on new frames. Couple of suggestions.
https://www.bike-discount.de/en/shop/aluminium-8675/l-24
https://www.chainreactioncycles.com/brand-x-rd-01-road-frame-and-carbon-fork-2019/rp-prod130456 (be careful - I think there is no disc brake mount on this frame).
Note that whatever you decide to do, you should not use the bike much in the meantime - the components increased wear will add up to whatever you have to spend on repairs.
Comment: Brand-X is an in house brand of Chain Reaction Cycles. Usually this kind of in-house brands are OK, but I don't have any first hand experience. Recommendation was based on price.

Also note, that this particular frame seems not to have disc brake mount. You would have to run rim brake back, ant that may require replacing the rim on the wheel.
Comment: Thanks man. Is there any reason why you recommend Brand X? Never heard of it, and the price is surprisingly low.
Comment: Unless you really want a specific frame I'd just find one secondhand, You can usually get a higher quality frame for a lower price.  It will be a bit more work on your end though, so up to you whether time or money is more important to you.
Answer: Further data - a change in geometry like that can screw up the handling something awful.
I rode this damaged steel-frame bike for a while:

That photo was before I straightened it somewhat with clamps and cold pressure.  Being steel that was much more acceptable than your bike where straightening will weaken the metal further.
The bike was "okay" but always a bit odd on fast descents.  In later rides I wore out the wheels, so fitted a used pair with different rim shape.   Immediately the hill handling got horrible, to the point I wondered if my wheels were faulty.  Inspection showed they were fine.
On a trip with another rider, he commented that my rear wheel looked "buckled" while descending.  It turned out the seat stay was flexing more on one side than the other, making the dropouts move relative to each other.
This also backed off the cone nuts over time, which didn't help.
Upshot?  Frame's toast and should be replaced for peace of mind.


Do I need to keep Title Insurance policy in a safe place

Question: Whenever one buys a property (with a mortgage) lawyers usually include a title insurance policy with the closing documents. Does one need to keep it in a safe place? How long does one need to keep it? Is there a copy available somewhere else in case the original is misplaced over the years?
Answer: Disclaimer: what I say below applies to at least one State in
the US but not necessarily to other States which may have different
ways of handling the mechanics of real-estate transactions. I am told
that in some States, closing a real-estate purchase transaction is
a far simpler process than in other States.

When real property is sold, the title to the property passes from the seller
to the buyer, and thus it is in the best interest of the buyer to make sure that
the seller indeed has legitimate title to the property when the sale is executed.
A title insurance policy ensures that in case of a defect in the title which
invalidates the sale, the beneficiary of the policy (OP) does not lose all the
money invested as well as the entire property. In many jurisdictions in the US,
the buyer asks the seller to provide the title insurance policy (typically
issued by the title search company that did the legwork). When a bank is
issuing a mortgage loan to enable the buyer to acquire the property,
the bank is definitely
going to demand that someone provide a title insurance policy to shield the
bank from defects in the title. In such cases, there are often two title insurance
policies, one that protects the bank (usually for the amount of the loan)
and another that protects the buyer for the full sale price, with one of the
policies essentially being a rider on the other and thus available for
a smaller premium than the premium for the main policy.  (Title insurance
policies are usually single-premium policies).
So, with that as prologue, the answers the OP seeks are

Does one need to keep it in a safe place?

Yes, it protects you even if it is a single policy that pays
off only the bank for the amount of the loan and doesn't cover
you at all.  If a long-lost heir shows up claiming that he is
co-owner with his brother the seller, and that his brother had
no right to sell the property without his (Robinson Crusoe's)
consent, and as a result, the sale to you
is invalidated by a court, you have lost the house (and all your down-payment
etc as well) but you nonetheless still owe the bank the unpaid principal
of the mortgage  (note: mortgage means "death-grip" (on the throat)).
In such a case, you can pull out the "bank's interest only"
policy to pay off the bank and keep it off your back as you try to put your life
back together. In the best of all possible worlds the policy covers
you as well, and thus while you lose the house,
you at least get back your equity and don't have to hassle with the bank.

How long does one need to keep it?

Till the property is sold. If you have a title insurance policy
in place when you prepare to sell the property, you might get a break on
premium for the title insurance policy that you will need to provide
to your buyer (or his bank) especially if it is the same title search
company that will be issuing the new policy.

Is there a copy available somewhere else in case the original is misplaced over the years?

Depends. But why not just stick the policy in your safe-deposit box
with a copy in your filing cabinet? Your heirs might very well need
it when they come to sell their late lamented parent's possessions.
Comment: Thank you for a detailed answer. Do you know if the new policy is issued when the property is refinanced? If so does the previous become cancelled?
Comment: The answer depends on the refinancing deal. Is it the same bank or a different one? Was another title search required (e.g. to ensure that there are no mechanic's liens or other liens (e.g. tax liens) on the property etc)?
Answer: This answers a more general case than your question:
I suspect other people have copies (I think lawyers need to make and keep copies of pretty much everything). But if all other people lose their copies (fire, faulty process, incompetence, fraud), it's good to still have a copy of any contract-like document you own.
In my case I keep all legal documents in a desk drawer and as a digital copy at a different physical location (in case of fire).
Answer: I would keep it until you sell the house in case any issue ever arises.
Comment: I was attempting to address the first two parts of the question "Does one need to keep it in a safe place" (Yes) and "How long does one need to keep it" (for as long as you own the house).


Can muslims play die / dice based board games?

Question: I was told that playing games such as Ludo or Snakes and Ladders is haraam as you use a die / dice. What is the correct opinion on this.
Answer: Playing any game where dice are involved is forbidden.
The Prophet ﷺ warned us against using dice in general:

عَنْ عَبْدِ اللهِ بْنِ مَسْعُودٍ قَالَ: إِيَّاكُمْ وَهَاتَيْنِ الْكَعْبَتَيْنِ الْمَوْسُومَتَيْنِ اللَّتَيْنِ يُزْجَرَانِ زَجْرًا، فَإِنَّهُمَا مِنَ الْمَيْسِرِ
'Abdullah ibn Mas'ud said, "Beware of these two marked cubes. They should be forcibly prohibited. They are part of gambling."
— Al-Adab Al-Mufrad, Book 54, Hadith 12

The two marked cubes are the dice. He also said that playing with dice is like dying one's hands with the flesh and blood of swine:

عَنْ سُلَيْمَانَ بْنِ بُرَيْدَةَ، عَنْ أَبِيهِ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ: مَنْ لَعِبَ بِالنَّرْدَشِيرِ فَكَأَنَّمَا صَبَغَ يَدَهُ فِي لَحْمِ خِنْزِيرٍ وَدَمِهِ
Buraida reported on the authority of his father that Allah's Apostle (ﷺ) said: He who played Nardashir (a game similar to backgammon) is like one who dyed his hand with the flesh and blood of swine.
— Sahih Muslim, Book 41, Hadith 11

Imam An-Nawawi said in his Sharh that nardashīr means dice and that the hadith above is what Imam Ash-Shafi'i and the majority of scholars used to declare playing with dice forbidden. Imam Malik is of the same opinion; he narrated a story about 'Ā'isha renting her place to people who owned dice. She threatened them to remove the dice from her house or leave:

عَنْ عَائِشَةَ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ بَلَغَهَا أَنَّ أَهْلَ بَيْتٍ فِي دَارِهَا كَانُوا سُكَّانًا فِيهَا وَعِنْدَهُمْ نَرْدٌ فَأَرْسَلَتْ إِلَيْهِمْ لَئِنْ لَمْ تُخْرِجُوهَا لأُخْرِجَنَّكُمْ مِنْ دَارِي وَأَنْكَرَتْ ذَلِكَ عَلَيْهِمْ
Yahya related to me from Malik from Alqama from his mother that A'isha, the wife of the Prophet, may Allah bless him and grant him peace, heard that the people who lived in a room in her house had some dice. She sent a message to them, "If you do not remove them, I will remove you from my house," and she reproached them for it.
— Muwatta Malik, Book 52, Hadith 6

It is clear that she did not even want to be in the presence of dice in the same place, let alone play with it. Imam Malik narrated another hadith about the prohibition of dice:

عَنْ أَبِي مُوسَى الأَشْعَرِيِّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ: مَنْ لَعِبَ بِالنَّرْدِ فَقَدْ عَصَى اللَّهَ وَرَسُولَهُ
Yahya related to me from Malik from Musa ibn Maysara from Said ibn Abi Hind from Abu Musa al-Ashari that the Messenger of Allah, may Allah bless him and grant him peace, said, "Whoever plays games of dice has disobeyed Allah and His Messenger."
— Muwatta Malik, Book 52, Hadith 6

Accordingly, since dice are of and by themselves forbidden, any game that uses dice is consequentially forbidden, board games (Ludo, Snakes and Ladders, etc.) included.

Reference from Islam Q&A: Does Ludo come under the heading of dice games which are prohibited?
Answer: I have seen many mufti saying playing ludo and games which do not involve gambling is allowed in islam. And about playing with dice in hadees that is in Arabic nerd which is obviously not ludo. Nerd is a game which nazashi or others kings at that time used to play which involve gambling. It was not ludo. Ludo was not based on guessing too.
Comment: Can you give me the source so I can research it and make a decision in if I believe it is halal or haram, because if you do not give me the source I would have to make a decision based off of what I think and that is very dangerous, because you do not want to make a decision off of your own thinking, you have to make it based off of the sources you used to come to that conclusion.
Answer: Ludo is not haram and @Ashraf is right.
There's a thing called nard it's also found on https://en.wikipedia.org/wiki/Nard_(game) and includes gambling so it's very different from ludo. If you search "nard" on Google images and see how it looks you can clearly tell its different from ludo and  that ludo is halal.
Image


How can I change this sentence into passive voice ?

Question: Question: I study with Mrs.Cara
Answer: I am studied with Mrs.Cara
Or I am made to study with Mrs.Cara
Which one is correct ? Please help me !
Answer: Study is intransitive in this case and thus cannot be made passive. Only transitive verbs cane be made into passive voice.

I am studied with Mrs. Cara

This implies that someone other than you and Mrs. Cara is studying you and her. It's an unusual sentence but grammatical, but also not the passive form of your original sentence.

I am made to study with Mrs. Cara

This implies someone is causing you to study with Mrs. Cara. It's grammatical, but not the passive version of the original.
Answer: "Study" can be both an intransitive verb (takes one noun, the someone/thing doing the action) or a transitive verb (takes two nouns, subject which does the action and object which receives the action)

Active: [someone or something S] studies [someone or something O].
Passive: [someone or something O] is studied by [someone or something S].

As you can see, you just switch the two nouns.  In your first answer:

I am studied with Mrs. Cara.

You are the [someone or something O].  Like, say, a police officer is studying you to see if you are a criminal.  This changes the meaning from your original active sentence, where you were the [someone or something S].  Almost nobody would say this new sentence because the reader of the sentence would certainly be interested in who you are being studied by!
Your second answer:

I[O] am made to study with Mrs. Cara (by my teacher [S]).

Be careful!  This is a valid passive construction.  However, you are now the object of the verb "made to", something which was not in the original sentence.  It works since even though you're the object of "made", you are still understood to be the subject for "study".
To make the pure sentence from active to passive for a transitive verb, you need to make sure you know both the [A] and the [B].  What are you studying?
So a pure sentence, where you don't add any unnecessary meaning, looks like this:

Math [B] was studied by me [A] with Mrs. Cara.

You can also optionally drop the [A].  ("by" part)

Math was studied with Mrs. Cara.

This sentence is quite awkward for a native speaker.  Most of the time, using the active tense is better.
As a side note, passive voice is impossible with intransitive verbs such as to sleep.  The only way to make a passive sentence is to do what you did, and change the verb to "make", a transitive verb.

I was made to sleep [by my mother].
I was made to study [by my teacher].

Be aware that adding the verb "make" adds extra meaning to the sentence, since it implies someone is influencing you to do it.


Average Price of a Stock

Question: I realized that most finance and stock screener web sites don't provide the metric of the mean (average) price of the stock over a certain period of time, for example, the mean value of AAPL shares over the last 12 months (which I computed to be around $117 from 2015-02-20 to 2016-02-19). Is there a reason for this? Is this metric useless?
Answer: Edit3: Regarding the usefulness of the bare number itself, it is not useful unless, for example, an employer uses that average in the computation of how many options the employer grants to the employee as part of the compensation paid. One of my employers used just such an average. What is far more common is to use two or more moving averages, of different periods, plotted on a chart.
My original response continues below...
Assuming there are 252 trading days a year, the following chart does what you have done but with a moving average:
AAPL on Stockcharts.com
Edit: BTW, I looked up the number of Federal holidays, there are 9. The average year has 365.2422 days. 365.2422 × 5/7 = 260.8873. Subtract 9 and you get 251.8873 trading days in the average year. So 252 is a better number for the SMA than 250 if you want to average a year.
Edit2: Here is the same chart with more than one average included:
AAPL chart w/indicators
Comment: This is the most correct answer.
Comment: @JoeTaxpayer [Definition of Tropical Year](https://en.m.wikipedia.org/wiki/Tropical_year)
Comment: @JackSwayzeSr - never too old to learn something new. thanks
Comment: Not 365.25? Where does that difference come from?
Comment: This doesn't answer the question at all.  The OP asked about the utility of this data. This gives a way to compute a number, but it doesn't answer the question of whether that number is meaningful.
Comment: @Brick I edited my response to address the utility of such an average
Answer: That metric is not very useful for anything other than very extremely long trading periods.
Most strategies or concerned with price movement over much shorter time frames, 15 mins, 1 hr, 4 hr, daily, weekly, monthly.
The MA or moving average is a trend following lagging indicator used to smooth out price fluctuations and more accurately reflect the price of trading instrument such as a stock (AAPL), commodity, or currency pair.
Traders are generally concerned with current market trends and price action of the instrument they are trading.
As such, an extremely long MA (average daily price, over a period of 365 days) are generally not that important.
Comment: That is not true regarding long MAs, in fact the 200 day MA is generally used by many to determine the general trend of a stock or the market. Traders can be very short term based to very long term based. There are trends that last minutes, trends that last days, trends that last weeks and trends that last years, by saying an extremely long MA is generally not that important is very incorrect, they can be more important than short term MAs.
Answer: I would have to disagree with the other responders. In technical analysis of stock charts, various short and long term moving averages are used to give an indication of the trend of the stock in the short and long term, as compared to the current price.
I would prefer to use the term moving average (MA) rather than average as the MA is recalculated every day (or at appropriate frequencies for your data) on the period you are using. I would also expand on the term "moving average". There are two that are commonly used

Simple Moving Average (SMA), this gives the average across a number of data points, giving equal weight to the most recent and the furthest away in time.
Exponentially Weighted Moving Average (EWMA), this gives the average across a number of data points, giving more weight to the most recent and less weight to the furthest away in time, based on an exponential weighting factor.

Going back to the question, of the value of this number, For example if the current price is above the 200 day EWMA and also above the 30 day EWMA, then the stock is broadly trending upwards. Conversely if current price is below the 200 day EWMA and also below the 30 day EWMA, then the stock is broadly trending downwards. These numbers are chosen on the basis of the market you are trading in, the volatility and other factors.
For another example of how a number of moving averages are used together, please have a read of Daryl Guppy's Multiple Moving Average, though this does not use moving averages as large as 200 days.

Average Price of a Stock


xBox One Streaming not take over console?

Question: Can i stream/play xbox one on my Windows 10 without it taking over the console? Ideally we'd keep watching TV on the xbox one, or watching Netflix, and kids could play on Win10.
Comment: you can use a hdmi cable and plug it into the screen, if the monitor has that capability, so you won't have to worry about conflicts with Win10?
Answer: It's unclear to me what you mean by "take over the console" as the console (in my mind anyway) is referring to the large cuboidal brick that is the XBox One itself.
When you stream from your XBox to Windows 10 you basically see (are mirroring) the "display" portion of the XBox on your PC.  You can continue to use your controllers normally, as they are acting directly as input device to the console itself.  If your TV has multiple input sources you can switch to another input and watch (e.g.) Netflix coming from another device while the kids play on the XBox One.   The only restriction that I have found is that somebody has to be signed in to the XBox before you can start streaming.
As an example, our setup has a Blue-Ray player with Netflix and other streaming services on HDMI2 and the XBox One is on HDMI1.  I can stream the XBox to my laptop and see the screen content there while I use the XBox controller to control whatever I am doing.  At the same time my TV can be on HDMI2 and be showing something on Netflix.
Comment: @DavidLozzi Ah, glad I was helpful.  I didn't even realize the XBox itself could do stuff like Netflix, as I had the BR player long before the XBox and never had the need to find out if it could do that.
Comment: Awesome, thanks for the reminder. When I posted this I only had the Xbox for media. Since then, I've purchased a smart tv, in which has these other services so this could work now ;)


Batch Update Permissioned Relationships

Question: We have a specific contact/organization relationship type that should be a permissioned relationship for the contact to edit the organizations record.  When we converted to Civi many of these contacts did not get the permissioned relationship check box checked. Is there a way to update the Permissioned Ralationship check box for this specific relationship type in bulk?
Answer: Unfortunately, there is no way to batch update relationship via the user interface b/c relationships are reciprocal. Using the Import Contacts wizard and selecting "Update" doesn't allow you to designate a relationship as permissioned either.
If you have a programmer on hand, this type of update would be easy to do using an SQL query directly on the database:
Assumptions:

Relationship Type ID = 4 (in my environment, this is the ID for Employee/Employer)
Contact A = Individual
Contact B = Organization

Query:
UPDATE civicrm_relationship SET is_permission_a_b= 1 WHERE relationship_type_id= 4
Alternatively, if you have sufficient permissions, you could use API Explorer as documented HERE, but this should only be done by someone who has good knowledge of the CiviCRM database structure.
Good luck!

Batch Update Permissioned Relationships


Would a modern processor/ALU process data bit or byte wise?

Question: We look at 32 bit and 64 bit systems with octal-core processors.
What does all that mean? As in, does it have 8 processors that operate bit wise?
Or do they all operate on 32/64 bit blocks.
I was studying Crypto with stream and block ciphers. And this has been confusing me now.
Also, is it fair to say that a computer has no value for "bytes" as there aren't anything more than our way of grouping bits to make them more convenient to read?
Comment: "Octal-core" means a [multicore processor](https://en.wikipedia.org/wiki/Multi-core_processor) with 8 cores.
Answer: Modern processors have 32/64 bits integer and 32/64/80 bits floating-point registers and ALUs. With the addition of SIMD instructions, extra vectorized ALUs are available and can perform operation on up to 64 bytes or 32 shorts (16 bits) or 16 ints (32 bits) or 8 long ints (64 bits) simultaneously and similar figures in floating-point (hence 512 bits at a time - Intel AVX).
A core is a full processing unit packaged in the same physical (multi-)processor.
So in a way, you can say that an octo-core can process 4096 bits of data at a time.

It is not fair to say that a processor ignores bytes, because the arithmetic operations need to know how many useful bits there are, to handle borrows, carries, overflows... Not to mention the floating-point data types, such that the value is split in several bit fields with different roles (sign, exponent, mantissa). In fact, a processor distinguishes dozens of data types of various lenghts.
It would be more true to say that processors don't known about bits because these are never handled individually, but as a minimum grouped in bytes. Even the very first microprocessor in history, the 4004, was handling nibbles (4 bits at a time).


Why is there a question mark at the end of Mark 7:19?

Question: I would like to know the purpose of the question mark at the end of this verse mark 7:19
No question is being presented. A inquiry is being answered.
If anyone could clear this up for me I would appreciate it greatly.
Comment: Could you please quote the translation you're working with? Different ones handle this differently. [This post](http://meta.hermeneutics.stackexchange.com/a/810/3555) explains the preferred way to cite the bible on this site. Thanks.
Comment: We discussed this verse here: [Is there any reason to think that Mark 7:19 has a later addition?](http://hermeneutics.stackexchange.com/questions/13415/is-there-any-reason-to-think-that-mark-719-has-a-later-addition?rq=1)
Comment: For an analysis of the Greek I recommend: http://dailydoseofgreek.com/scripture-passage/mark-7-19/
Answer: Mark 7:18b -19 (ESV, NA28):

Do you not see that whatever goes into a person from outside cannot defile him,
  οὐ νοεῖτε ὅτι πᾶν τὸ ἔξωθεν εἰσπορευόμενον εἰς τὸν ἄνθρωπον οὐ δύναται αὐτὸν κοινῶσαι,
since it enters not his heart but his stomach, and is expelled?"
  ὅτι οὐκ εἰσπορεύεται αὐτοῦ εἰς τὴν καρδίαν ἀλλ' εἰς τὴν κοιλίαν, καὶ εἰς τὸν ἀφεδρῶνα ἐκπορεύεται;
(Thus he declared all foods clean.)
  — καθαρίζων πάντα τὰ βρώματα.

There is a question, but it's a rhetorical one.
The question in question begins in verse 18 with οὐ νοεῖτε ὅτι ("Do you not see that..."). The structure of the question beginning with οὐ indicates that an affirmative answer is expected.1  This is a common rhetorical technique in Koine Greek that we reproduce somewhat clumsily in English with the "Do (am/is/are) not...?" construction. "Do you not know/see/understand...?" is a frequent application of this construction that conveys a gentle rebuke upon the ignorance reflected in the inquiry.
The sense of the expression is adequately conveyed in most translations as in the ESV quoted above, ending with a question mark.2

1. Mounce, William D. Basics of Biblical Greek. Zondervan, 2009; p. 295.

2. The ; in Greek is equivalent to the English ?.
Comment: **he** & **declares** does not exist. katarizon [cleansing] panta [all] ta bromata [foods]. He does not but the guts cleanses itself from food! It's not a question but a statement that 99% of Christian can't see what he says nor what it means.


Why is there a factor of $4\pi$ in certain force equations?

Question: I mean to ask why there is $4\pi$ present in force equations governing electricity? Though all objects in universe are not spherical and circular, the constant of proportionality in both equations contain $4\pi$. Why?
Comment: Possible duplicates: https://physics.stackexchange.com/q/1673/2451 and https://physics.stackexchange.com/q/28673/2451 and links therein.
Comment: Can you give examples? In which unit are you using them?
Comment: It comes from the integral in spherical coordinates.
Answer: For example, if you mean $k_e=\frac1{4\pi\epsilon_0}$, it comes from a natural "Gauss's law" understanding of Coulomb's law, where the electric field is distributed over the surface of a sphere of area $4\pi r^2$.
$$F=  \frac1{\epsilon_0}\frac1{4\pi r^2}q_1q_2  $$
This is also the explanation for the $1/r^2$ term (and in other classical fields), and there are also attempts to extend this sort of reasoning to gravitational fields.
Answer: If you want to avoid factors of $\pi$ in the more fundamental equations like $\nabla . E = \rho / \epsilon_0$, you have to accept them where they belong, for instance in: $E = \frac{1}{\epsilon_0} \frac{Q}{4 \pi r^2}$.
As remarked by others, Newton failed to put a factor $4 \pi$ into his gravitation equation (he stipulated $g = G \frac{M}{r^2}$, instead of $g = G \frac{M}{4 \pi r^2}$) and as a result we have to live with factors of $\pi$ in the more fundamental Gauss' law for gravity, and more importantly, also in Einstein's theory of gravity.
Comment: Does this imply that Gauss' law of gravity is simply an equivalent of Newton's law of gravitation which includes the $\frac{1}{4\pi}$ factor in a relevant context? From what I've seen of the link in your answer, it seems to be so, but I'm not sure that my inference that Gauss' law has no further implications beyond those of Newton's is correct.
Answer: The physical reason for the appearance of a $4\pi$ somewhere in the theory is the spherical symmetry of the problem and is discussed more in other answers . Here I want to quote an interesting argument from Arnold Sommerfeld's Lectures on Theoretical Physics Vol III, which has a section dedicated to this issue.
If you remove the $4\pi$ from the force law you will have it in more fundamental Maxwell's equation:
$$\nabla.\mathbf{D}=4\pi\rho$$
and also it will distorts the energy density into:
$$W=\frac{1}{8\pi}\mathbf{E}.\mathbf{D}$$
But Heaviside, as is said in the mentioned book, who fought a life-long battle for the rational units $(4\pi$ present in the force law$)$, has another interesting argument about advantage of this system to others. He points to the capacity of a capacitor:
A plate capacitor (with area $A$ , plate separation $d$) in this rational units $(4\pi$ present in the force law$)$ and in other units $($with $ 4\pi$ present in the Maxwell's equations$)$  has a capacity of
$$C=\frac{\epsilon A}{d}\tag{rational}$$
$$C=\frac{\epsilon A}{4\pi d}\tag{others}$$
and for a spherical capacitor (radius $R$, outer sphere imagined at infinity):
$$C=4\pi \epsilon R\tag{rational}$$
$$C=\epsilon R\tag{others}$$
We see that with rational units the factor $4\pi$ appears for the sphere. For other units it is missing for the sphere and appears for the plane capacitor.
Heaviside then makes the following striking comparison: In passing from the measurement of distance to the measurement of area one might define as unit of area the area of a circle of radius $1$. This would be logically possible. It would however lead to the strange result that a square with the side $1$ would have the area $\dfrac{1}{\pi}$. Everyone would then say that $\pi$ was at the wrong place. We said the same of the factor $4\pi$ in the above formulas for capacities.
Answer: Any differential equation of the form $\nabla \cdot A = \alpha$ and $\nabla \wedge A = 0$ in $n$-dimensions has as its Green's function (that is, the solution for a point source, for $\alpha = \delta$, the Dirac delta function) a field $G$ of the form
$$G(r) = \frac{1}{S_{n-1}} \frac{\hat r}{|r|^{n-1}}$$
where $S_{n-1}$ is the surface area of a unit $n$-ball, which we know to be $4\pi$ in 3d.  The factor of $4\pi$ that appears in many such force equations is inherently geometrical, and as has been stated, it is confounding to lump it into a constant, especially if one works outside of 3d (see, for example, the electric field of a line charge, which is a 2d problem and thus has $2\pi$ appear in it, as circumference of a unit circle).
Answer: The main reason is that it makes the calculation easier and the results look nicer. For example, suppose the field (or force) is given by
$$ E = \frac{1}{4\pi} f(\mathbf{r})$$
for some function $f(\mathbf{r})$.
If the system process rotational symmetry, after sum over the density, you will get a factor of $2\pi$. If the system process spherical symmetry, you will get a factor of $4\pi$. In both case, the resulting equation contains no $\pi$ factor. It is particular useful in EM as we usually consider a density distribution process some symmetry.
So, why there is no $\pi$ in the Newtonian gravity $F=GMm/r^2$ ?
Because there is no such need. You cannot craft a planet like macroscopic object into a infinitely long rod, a disk shape, or some funny shape. Gravity only have significant effect when it accumulates a large mass, at the same time, it become a sphere by its own gravity. So, basically, it is already a good point like particle when we look at it some radius away. The extra $\pi$ won't make any calculation easier.
Comment: Actually if I could go back in time I would bonk Newton on the head (with an apple) and tell him to put in a factor of $4\pi$. For the sake of those who would come later. (That sounded less dirty in my head.)
Comment: @MichaelBrown Yep, it is also a historical problem :)
Answer: Some people (myself included) would regard field equations like Gauss' Law as more "fundamental" than force equations. The most obvious reason for this is that Coulomb's Force Law only works when the charges in question are held static - it has to be modified once they are allowed to move.
As the others have stated, the $4 \pi$ has to do with the surface area of a sphere. Gauss' Law (I'll use the integral form to make the surface area connection more apparent) for the electric field tells us:
$$\int \mathbf{E} \cdot \mathrm{d} \mathbf{A}= \frac{q}{\epsilon_0}$$
In words, this means that if you enclose some charges in an imaginary surface, then the sum of the electric field sticking out of that surface multiplied by the area of the surface is equal to the total charge enclosed by it, multiplied by some constant factor. If you take a single point charge and enclose it with a spherical surface of radius $r$, then it reduces to:
$$4 \pi r^2 E= \frac{q}{\epsilon_0}$$
Do some rearranging and it's easy enough to see how it relates to Coulomb's Law.
There's also a form of Gauss' Law for (Newtonian) gravity:
$$\int \mathbf{g} \cdot \mathrm{d} \mathbf{A}= 4 \pi GM$$
This field equation actually contains the factor $4 \pi$ already, so when you enclose a mass with a spherical surface the factor cancels on both sides. This is simply because when Newton wrote down his force law for gravity he didn't know about things like Gauss' Law, and so neglected to include the $4 \pi$ in the force equation. And since then the convention has stuck around, so we're left with a slightly confusing hodgepodge of some field equations needing factors of $\pi$ and some not. In general, if you see a factor of $\pi$ in a field equation then you're probably looking at something gravity-related.
Answer: It's just a result of Gauss theorem applied in symmetry in this case  surface area of sphere with charge placed at it's center.
Which is 4 Pi R^2