Buying a canon 5d Mark II with 120 000 shutter actuations?

Question: Would you consider buying a used canon 5d Mark II in mint condition with 120 000 shutter actuations for 500$? The seller is a nice lady, she is a professional phototographer. Here are some photos of the camera that she has sent me.
Comment: Related question: [How many actuations are "too many actuations"?](//photo.stackexchange.com/q/3813)
Comment: Camera looks clean. I found one on eBay for 1200 that's brand new. Given a few hundreds bucks for a shutter replacement on this one, you'd still be quite far from 1200. Seems like a decent deal to me!
Comment: 120000 is a lottery: it may broke next week or may work years and years. In our country the shutter replacement will cost 800 - 900 dollars. I suggest it may be good deal.
Comment: @ViktorTomilov, how is that a good deal when you could buy the camera itself for that price instead of just a shutter?
Comment: @walther I cannot buy that old camera for 800-900 bucks in my country (Too old and broken is not for sale, in good conditions can cost more). It consts more than that summ. But repairing will be with 1 year garantie and with ckecking of all other parts. So I think that is good deal.
Answer: I tend to equate shutter click counts with car mileage. To me, your question's equivalent car shopping question is: Would you buy a 2008/2009 used car with 120,000 miles on it for 1/5 of what it went for new?
You may also want to look at this website:

The graph is based on a survey from 5DMkII owners, who navigated to the site themselves, about when their shutters failed/are still alive. The page states:

Average number of actuations after which shutter is still alive: 137,709.5
Average number of actuations after which shutter died: 171,076.9

It looks like the failure rates begin to increase right bang on the 100,000 mark, which is the typical lifespan spec for Canon's shutter mechanism, iirc.
Based on a Kaplan-Meier statistical analysis of the submitted data, you have about a 3 in 4 chance of making it to between 250,000 and 500,000 and a 2 in 3 chance of making it to between 500,000 and 1,000,000 actuations. There's only about a 1 in 8 chance that the shutter will fail at between 100,000 and 150,000 actuations. Canon rates the shutter of the EOS 5D Mark II at 150,000 actuations.


Meaning of this symbol

Question: What is the mathematical meaning of a horizontal A. I mean that it is like this > but crossed which makes it look like a horizontal A.
Comment: Do you mean $\not>$?
Comment: You might get a better response if you include a picture of the item in question.
Answer: Usually, a slash on symbols in mathematics indicates a negation of the original meaning of the symbol.
For example, \begin{align}=\quad&\to\quad\ne\quad(\text{equality})\\\mid\quad&\to\quad\nmid\quad(\text{divisibility})\\\in\quad&\to\quad\notin\quad(\text{element})\\>\quad&\to\quad\ngtr\quad(\text{greater than})\\<\quad&\to\quad\not\lt\quad(\text{less than})\\\sim\quad&\to\quad\nsim\quad(\text{distribution})\end{align}
Comment: it seems pretty logical indeed and thank you for the answer but it did not look like a slash to me, more like an actual horizontal A with the slash looking more like this | and not going out of the >. I probably am just making my life complicated though, thanks!
Answer: $\ngtr$ means not being superior (greater) than something. It is the negation of $>$
Answer: "≥" This means "equal or greater than"
">" This means "greater than" (being equal is not included)
"≯" This means "no greater than" <= What the hey is the difference between this brat and "≤"???

Meaning of this symbol


Overstayed Student Visa for 2 years in Canada, almost 8years ago

Question: I overstayed my student visa in Canada for almost 2 years..that was almost 8 years ago I voluntarily left after my overstay and after moving back I have a full time job etc. here now..I want to get a visitor visa this year to visit friends in Canada, will I face any problems/rejections/bans when I apply..I have no intention on staying back and I want to just visit for 2 weeks any way I can make that clear to them? or Should I not even bother applying?
Comment: I'm not sure anyone here can offer anything but advice. What did the paperwork state when you voluntarily left? Were you banned?
Comment: I didn't receive any letter asking me to leave..I wasn't issued any deportation letter or anything of that sort..I just left voluntarily when I realized I was doing a stupid thing..Canada doesnt have exit controls so they dont really even bother looking at how long you stayed there etc.
Comment: So you have no proof that you overstayed? More importantly, *Canada* has none? hmm, if true, then who heard the tree fall in the forest?
Comment: They obviously can check records I think on airline and entry dates but they dont stamp your passport or have the forms like US, its not obvious if they dont check records I meant to say..I am just worried about it if I'm going to be banned or something then I would just avoid travelling there altogether..
Comment: I think your best chance is to ask for a visa, it is the best way to know if it is possible to go. What I mean is people who do not need a visa do not get to know if they will enter until they actually arrive at the border.
And as you will also visit the US, if the border agent refuses you, you can still go back to the US and fly from the US to Paris.
Comment: Finding an airline record from this many years ago will be incredibly difficult if at all possible. For example, the EU http://www.theguardian.com/world/2011/may/25/us-to-store-passenger-data keeps PNRs for at most five years.
Answer: This is going to depend almost entirely on whether Canada knows you have overstayed.  If they don't, you should be OK; if they do, you're very likely to get rejected.
In your shoes, I would just try my luck, and have a plan B in case you don't get the visa.  Note that you will likely have to lie on the application, both about overstaying in Canada (you don't want to say "Yes" to this) and about previous visits, although this could go both ways: it's risky to say you visited Canada before, and it's also risky to omit the visit.  My gut feel is that it's better to list your previous visit and give the dates your visa was granted for, but YMMV.
In any case, apply for the US & European visas first and book your flights to Paris from the US, not Canada.  This was, any Canadian rejection doesn't affect them.  You might also want to consider getting a new passport first, so the fact that you didn't leave Canada for two years is not obvious.
Comment: The application form is here: http://www.cic.gc.ca/english/pdf/kits/forms/IMM5257E.pdf  And yes, you are asked about previous travel.
Comment: And you'll be banned (or not) because of the previous overstay, not because you apply.  But if you want to play it 100% safe, just don't visit Canada.


Linux OS patch vs kernel patch vs firmware upgrade or BIOS upgrade

Question: Can somebody explain the difference between a Linux OS patch, Linux kernel patch, vs a firmware upgrade or a BIOS upgrade?
Comment: And microcode? (If I can extend the question)
Comment: You can, and I replied. To extend a question, click [edit] and expand on what you first asked. That's better than adding a Comment, as Comments can get lost when they pile up.
Answer: Microcode
A microcode update is a file from your CPU manufacturer, that is fed to your actual physical CPU and makes changes to its internal, lowest-level programming. Because it takes effect on such a low level, microcode updates are normally not persistent: each time a processor powers up or is reset at the hardware level, a microcode update needs to be reloaded. Microcode updates tend to be very specific to particular CPU make and model.
Firmware update/upgrade
A firmware update changes/replaces some persistently-stored program code within a specific unit of hardware, that usually deals with operating that hardware in some way. A BIOS or UEFI update is a special case of a firmware update: BIOS/UEFI is the firmware that deals with how your system starts up, detects the various add-on cards and devices integrated on the motherboard and assigns hardware resources for them, configures low-level power management and provides the basic input/output functions that will be used by the bootloader of the operating system.
A BIOS/UEFI update/upgrade can include a microcode update embedded within it: this way, the microcode will be applied at a very early phase of the boot process, to ensure that the operating system will always get the CPU in a state that includes at least that particular microcode level applied to it, and no software can exploit the old "bad" microcode version any more.
Patch
In this context, the word patch properly refers to an update that does not include a complete copy of the thing being updated, but just the changed parts. There is a tool that can apply the patch, i.e. take the old version and the patch made for it, and use them to produce a new version that is exactly identical to what the creator of the patch had.
This was originally just a way to minimize the size of the updates, but with proprietary operating systems, it also allows OS vendors to get paid for the OS while distributing updates essentially without restrictions: it would be either impossible or at least incredibly hard to take the full set of patches published for a particular OS and assemble an unlicensed copy of the OS from them, like a giant jigsaw puzzle.
In software development, patches are useful in communication between developers: a source code patch file will describe exactly what's been changed in a human-readable way, so two developers working with the same thing can show each other exactly what modifications they've done to achieve a particular thing by creating patches out of their changes.
With modern Internet speeds and storage device capacities, updates to firmware or software that is already in binary form are not typically released as patches any more: it is far more common to provide a new software package or a firmware file that completely replaces the original. Nevertheless, some people may still talk about firmware patches or OS patches. This may be because they're treating the term patch as equivalent to update, or because they are thinking at the software development level.
When e.g. a firmware bug is discovered, a fix for it may well start its life as a patch applied to the source code of the firmware, and then producing a new binary firmware update file from the modified source code is just a boring, mechanical, repeatable process; the patch effectively is the "interesting part" of the update.
OS patch vs. kernel patch
When someone is talking about "Linux OS patches" without specifying exactly what tool or library is being patched, they're most likely talking about new .rpm, .deb or similar package files that completely replace older version of corresponding packages, so "update" or "upgrade" might be a more accurate term. Such a package can be used to update/upgrade a specific part of your operating system: a specific tool, a set of tools for a particular purpose, or a particular system service.
This can also be true about "kernel patches", but it is also possible that the speaker is actually participating in kernel development and talking about patches to the kernel source code. Or they might be focusing on the "interesting part" of a particular kernel update: a source code patch that fixed some bug or introduced a new feature.
Answer: A firmware or BIOS patch is code from a hardware or CPU manufacturer which is installed into the writable memory of hardware and are stored in hardware through shutdowns. They could go into the motherboard, a video card, the CPU itself, or into other devices. Turning your PC off does not erase them.
Microcode more is specifically a patch for the CPU.
Patches of Linux OS, the Linux kernel, or other operating systems, are written into a drive, whether a solid state drive ('SSD') or a hard disk drive ('HDD').
They are retrieved from the drive every time your PC boots, and erased from the PC's RAM when the PC is turned off. (That's the design of a PC, anyway; there are sneaky ways to retrieve the contents of memory after a power-down, but that's outside of the scope of your question.)
What most folks refer to as "Linux" is the kernel plus all the packages which make it a practical tool for getting a job done with a computer, or writing scripts or programs which get a job done with a computer (here including 'entertainment', games and multimedia, as a job).  Some folks call that GNU/Linux, to differentiate Just The Kernel (Linux) from the distributions ('distros') with all those packages.


docker: Error response from daemon: OCI runtime create failed: container_linux.go:345

Question: I have downloaded the anaconda docker image from here and I am running it on MacOS.
I have come across the following issue and I would highly appreciate your help!
When I try running Ipython by the following command
docker run -it pyimg ipython

I get the error

docker: Error response from daemon: OCI runtime create failed:
  container_linux.go:345: starting container process caused "exec:
  \"ipython\": executable file not found in $PATH": unknown.

This makes me think that the $PATH in docker does not entail the location of ipython.
However, when I spin the container by first executing the bash and then by launching ipython, everything works fine!
More precisely,
docker run -it pyimg bash

and then
ipython

works fine..
To make things even more confusing,
docker run -it pyimg python

works perfectly!
I already checked inside the container and realized that both python as well as ipython are located in the same directory /opt/conda/bin
How is it possible that this behavior is exhibited and how can I fix it?
Thank you very much in advance for your help!
Answer: Executing:
docker run -it pyimg ipython

Implies you have iphython installed on your host OS. That is, on your MacOS as you stated. If iphython is installed, run it with privileged switch:
docker run -it --privileged pyimg ipython


Realistic 3D Collision Detection Implementation

Question: I understand how box collision, sphere collision, and other such collisions work. However, how would one implement realistic 3D collisions? That is, objects would interact with one another as they would in real life. For example, take a rod and a torus. Assume that the thickness of the rod is smaller than the hole in the torus. With simple collision systems, as far as I know, inserting the rod into the hole of the torus would result in a collision detection. In reality, no collision would take place. Hopefully, that explains what I am looking for.
Comment: You're asking for an entire education in physics engines which includes: linear algebra + trig, brep models, spatial partitioning, solid body physics formulae, calculus for integration, and a basic understanding of simulations.  And that's not even including the religious differences between impulse/response and continuous integration strategies.  But if you really do understand box collisions, then imagine your torus made up of a bunch of tiny boxes... of course nothing would hit the boxes since there are none in the hole.  That's how it works =)
Comment: That's really nothing that can be answered in a comment. You should invest in a book about that topic, like http://www.amazon.com/Real-Time-Collision-Detection-Interactive-Technology/dp/1558607323
Comment: What have you researched so far?  Why do you assume a anything would collide with an open hole in a torus, for example.
Comment: Just use the model itself for collision detection, instead of simpler collision meshes. Be aware that this would consume a lot of execution time though.
Comment: @PatrickHughes, from my understanding of box collision, for example, a box surrounds the model in question (the torus) and would be used for collision detection.
Comment: @AdamS, how would such an implementation be done? Do you have an tutorials or websites you can link to?
Answer: You can compound various primitives together to add accuracy to your collision model. For instance in your torus example, you could have a bounding box or sphere around the entire model but then also have a sphere that just encompasses the torus' hole. Then the algo would go: if rod is in box but not in holeSphere, then it's colliding, else if rod is in box and holeSphere, it is not colliding.
You can often use a few basic primitives (planes, rays, boxes, spheres) together to get an acceptable level of accuracy.
Definitely get 'Real time collision detection' by Chtister Ericsson,.


How to join/cogroup by multiple fields in SAQL?

Question: I am new to SAQL and am trying to join two datasets (let's call them q and r) using cogroup. I have 4 columns in each table (let's call these A, B, C and D). Columns A - C are the same in both datasets but column D is different, so I want to use an inner join against columns A - C to produce a result that will have the columns A, B, C, D, E (renamed from D in the 2nd dataset). However, when I try to do this I am getting a number of errors.
So far I have tried the following:
q = cogroup q by 'A', 'B', 'C', r by 'A', 'B', 'C';
q = cogroup (q by 'A', r by 'A') and cogroup (q.'B', r.'B') and cogroup (q.'C', r.'C');
q = cogroup (q by 'A', r by 'A'), cogroup (q.'B', r.'B'), cogroup (q.'C', r.'C');
q = cogroup q by 'A', r by 'A' and q by 'B', r by 'B' and q by 'C', r by 'C';
None of these give me the desired a result and I get errors (not all the same errors) for each of these.
In each instance this has been followed by:
q = foreach q generate q.'A' as 'A', q.'B' as 'B', q.'C' as 'C', sum(q.'D') as 'D', sum(r.'D') as 'E';
I have struggled to find any examples online of where multiple fields are used for the join, can anyone provide any solution to this please?
Answer: You can cogroup by multiple fields using below syntax. Quoting your example above. Let say u want to cogroup 'q' datastream and 'r' datastream on these 3 fields 'A', 'B' and 'C'.
q = cogroup q by ('A', 'B', 'C'), r by ('A', 'B', 'C');


At what wattage does a pond pump pose a danger to human life?

Question: I am building a pond, and notice that pond pumps are available in incremental wattages and GPH. I'd like to choose a wattage that is safe, so in the event their is some electrical problem, no children are hurt touching electrocuted water. Is there a point where the wattage level becomes dangerous? If I keep below a certain wattage amount, does it make for no risk of death?
Comment: the pump is irrelevant ... what if you remove the pump and just leave the bare wires in the water? ... do you think that would be safe?
Comment: That's not how any of this works.  If you have the wiring, and the pump, installed per code, preferably by a licensed electrician, then GFCIs, circuit breakers, fully insulated connectors,etc. will guarantee no human risk exists.
Comment: I wouldn't size the pump for safety. Just be safe,  dangerous voltages depend on the person as well.  There are credible accounts of heard defibrillation with < 50V and 750mA. Many people wouldn't even notice that voltage at their fingertips.
Answer: The rated wattage of the pump won't really make a difference. If there is some sort of fault, it will likely allow whatever the supply has to give to flow. The solution you are looking for would be to make sure the supply you are attaching the pump to is ground-fault protected, by either having:

A GFCI-protected receptacle (GFCI built into the receptacle, or into a down-stream one connected through the LOAD terminals) or
a GFCI-protected circuit breaker

This will make it so that if there is a failure in the pump, the GFCI device will detect the failure and shut the power off.
If you are really worried about it, you may also look into low-voltage pumps. I am not sure if these exist or not, but I think this would be inherently less dangerous. However, GFCI protection is generally accepted to be perfectly safe for these types of uses.
Comment: Indeed, a GFCI is almost certainly required by the electric code for this use case.
Comment: Low voltage pumps are **widely** available, though mostly as "connected to low voltage solar panels" rather than cord and plug to low voltage adapter (at least *as sold.)*
Comment: Any electrical pump has the potential for being dangerous, but the size of the pump has little to no effect on the danger level. If the pump fails, it will be with the mains electricity "leaking" out... I think that this is the best answer from a safety perspective, but getting back to the pond... You'll need a pump that is properly sized for your pond. That includes the overall size of the pond and allowances for fountains, waterfalls, and "lifting" water above the surface of the pond (if necessary) or, otherwise, you're not going to be successful with your pond.
Answer:
Welcome network visitors. We're not talking pure science here; here on diy.se we deal in the practical world of Code compliant mains electrical installations.  Code is very clear that voltage is the deciding factor as to intrinsic safety, which is what OP is asking about.  If you have a theory question, by all means ask it on ee.se or physics.se; but that is not this question here now, and I am not answering a theory question. Here on DIY stack, we are aware of physics, but the laws we follow are passed by Legislatures.

Wattage doesn't make it dangerous. Voltage does.
Therefore, reducing wattage is not a safety strategy.
The reason voltage is dangerous is that it is the motive force that pushes electrical current through the human body.  If voltage is kept low enough, there simply isn't enough force to harm a human.
This is not a barrier to success, because what does the actual work is power (wattage), and that is voltage x current.  If you need to lower voltage, just raise current likewise, and you have the same wattage.
NEC (the model Electrical Code adopted by most US Legislatures) declares that up to 15 volts is generally recognized as safe in exposed outdoor conditions, so you can run any current you want to at 15V (or more likely, you would choose the very common 12V).
AC mains is 120V and up, and it's not sized to be safe - it's sized to be powerful.   They have GFCIs which are pretty good, but not quite perfect.
Comment: hey.. to be more precise.. Voltage is not the danger. its all about the Amperage -- to elaborate,  static electricity can be around 20000v .. -- then also conductivity is the other factor..
Comment: @Hightower well, of course, technically speaking. But in a "supplying power to a pump" scenario, this is utterly irrelevant. Voltage is very much the danger in this case, in that it's the voltage that drives the current that kills you.
Comment: A 12 V car battery is plenty dangerous and that is all about it's capacity for supplying current. Example: Accidentally arc-welding your wedding band to the car while handling a car battery. Also, voltage and current are both technically relevant though the current is what kills you (voltage makes it easier to deliver current through your body, but if a low enough resistance path is found through your heart, then a lower voltage could still potentially do it if it has enough capacity for current). Refer to IEC 60601-1.
Comment: @statueuphemism I think you mean "destructive".  If you want to claim "dangerous" you need to show a body count.  Darwin awards where a person intentionally implanted electrodes specifically to bypass skin resistance don't count :)
Comment: "Able or likely to cause harm or injury" (Oxford Dictionary). I think the potential for third degree burns and lost appendages count as dangerous by that definition.
Answer: TLDR
0.004 W is a theoretical safe limit for the power supply to the pump.
You're not going to find a pump at this wattage and as long as everything is installed per manufacturer recommendations with appropriate circuit protections, you won't be doing much to make things safer anyway.

Electrical current is what is fundamentally dangerous.
Depending on the path it takes through the human body, as little as 20 mA can be fatal.
As additional supporting evidence, the de-facto safety standard in medical device development (IEC 60601-1) specifies and tests only electrical currents with respect to patient safety (refer to section 8 of IEC 60601-1 Edition 3.1).
As an example of why voltage itself is not inherently dangerous without capacity for  current, think about electrostatic discharge (e.g. rubbing your socks on the carpet and then touching a door knob). This discharge can be a very high voltage (10 kV is used as an approximation in at least one model). However, discharge's capacity for current is very low and is therefore not dangerous.
However, current does not exist without voltage.
You don't get one without the other because of Ohm's law:

Voltage = Current * Resistance (V=IR)

Therefore, higher voltages make it easier to supply current through circuit paths with higher resistance and increase the likelihood of electrocution.
Per NIOSH 98-131: "Under dry conditions, the resistance offered by the human body may be as high as 100,000 Ohms.  Wet or broken skin may drop the body's resistance to 1,000 Ohms. ... High-voltage electrical energy quickly breaks down human skin, reducing the human body's resistance to 500 Ohms."
Putting the theoretical pieces together...

V_min_lethal = I_min_lethal * R_min_lethal

with

I_min_lethal = 0.002 A (20 mA)
R_min_lethal = 1,000 Ohms*

Therefore:

V_min_lethal = 1,000 Ohms * 0.002 A
V_min_lethal = 2 V

Theoretically, a voltage as low as 2V is potentially lethal!
And since you asked about wattage (i.e power) and P = IV, the lowest safe theoretical wattage is therefore 0.004 W. If you can find a pond pump that runs with those kinds of numbers... well good luck.
And to boot, it is really about the ability of the power supply (e.g. wall socket, marine battery, solar panels) to provide power. If a pond pump is working correctly, it should pose no risk to anyone. It is when it is in a fault condition (e.g. frayed wire, weathered insulation) that it becomes hazardous and at that point, the worst case assumption is the full power capable of being supplied by the power supply (with any independent safeties such as GFCI, circuit breakers, and fuses).
*The lowest resistance for the low-voltage model is used from the publication because the publication considers "high-voltage electrical energy" to be 600 V or greater and we are well below that threshold in this theoretical exercise.
Practical Perspective
From a practical perspective, is this worst-case scenario likely (or even probable)? No. People handle 12 V batteries on a daily basis and both 12 V and 24 V are very common in marine applications because of the significantly reduced probability of harm.
If safety is your primary concern, then the lower the voltage the better. However, proper and functioning GFCI circuit protections should make any solution about as safe as another.

An aside about the word "Dangerous"
There are a couple of potential harms resulting directly from direct contact with electricity:

Electrocution
Burn (caused directly by current running through tissue or by contact of the body with a short-circuited object)
Fall (e.g. locked muscles while working on a ladder and you fall off)

I would consider each of these to be potentially dangerous (though of differing severity) even though electrocution is the primary concern voiced in the question. Luckily, the same mitigations more or less work well for all of them. :-D
Answer: As few as 100 mA can stop a human heart. At standard US/NA 120 V, that comes out to 120V × 0.1A =12 watts.
Your not likely to find a useful pond pump at less than 12 watts. Furthermore, the power supply will certainly provide more than 12 watts of available power.
The only answer to be certain your pond is safe is to have everything is installed properly. A competent, licensed electrician is your best chance of completing the job properly.
Comment: It's not enough to say "the pump draws <100ma *under normal conditions*, there would need to be a device entirely outside the pool which limited current to non-dangerous amperage.  Otherwise someone could be killed during abnormal conditions.
Comment: @Harper-ReinstateMonica that was the point of my second paragraph. If you can edit it to more clearly express that I would appreciate it.
Comment: [statueuphemism](https://diy.stackexchange.com/a/196946/55821) expressed the idea I was trying to get across much more effectively. I will remove this answer tomorrow.


Why aren't AFCI breakers required for bathrooms/lavatories?

Question:
Why doesn't NEC require AFCI breakers for bathrooms/lavatories?
Is there a good reason NOT to install AFCI protection on a 15A/20A 120V bathroom outlet?  (I.e., use GFCI only.)
Comment: Related question: https://diy.stackexchange.com/q/153610/43874, not _really_ a duplicate, but similar.
Answer: We're reading tea leaves here to guess at NFPA's intent. National Fire Protection Association (NFPA) writes the "model electrical code" which they offer for anyone in the world to adopt as their law.
But politically, NFPA has been having a big problem.  Normally NEC changes are fairly trivial in cost: Pull a neutral wire on switch loops, gosh, you're using the /3 Romex instead of the /2.  It's maybe $3 per house.  Those increments have been getting bigger, as they've started so snake GFCIs and AFCIs in more and more places.
Mind you, AFCIs started out as a solution for electric blankets starting fires in bedding.  However, they discovered that in actuality, AFCIs were catching arc faults caused by backstab connections.  Backstabs are a builder favorite (jab a wire in a hole and you're done, instead of having to form a shepherd's hook and torque to spec, times  say 200 connections in a typical house). Builders don't want to quit backstabs. (if they fail after closing, who cares?)
Well, in 2014, NFPA was hellbound and determined to require AFCI or GFCI breakers on darn near everything.  And a lot of people were thinking "Why not just outlaw backstabs, then?"  Anyway, NEC 2014 was adding six hundred bucks to the cost of a house, which was actually going to have a material effect on real estate prices.
Builders were saying "Oh hell no", and telling their Congresspeople to say "Oh hell no". And NFPA had to lobby right back, and influence public opinion. So states adopted NEC 2014 very reluctantly (seven still haven't), and some states still adopted it with some AFCI/GFCI requirements left out.
Anyway, requiring both AFCI and GFCI on a circuit was politically "a bridge too far".
Comment: And those arc faults were caused by beds hitting the plugs, which was caused by uniformly placing receptacles in the middle of the wall instead of nearer the corners, which was caused by the 12' rule...
Comment: "as they've started so snake" should that be "to sneak"? If no, what the heck does it mean?
Comment: Also, is $600 really all that noticeable in a $150,000 house? True some houses are less expensive than that, but many are more expensive. According to [this](https://dqydj.com/historical-home-prices/) (seems like reasonable source, near the top of the search results), the median house price in June 2020 is $278,000. That's 0.2% of the median sales price of a house!
Comment: This will change with the 2020 NEC...
Comment: @FreeMan Sneaking like a snake... sneaking makes it sounds like doing something illicit, but it's their job to do that...
Answer: NEC doesn't require AFCI because it does require GFCI, and they are not the same.  GFCI outlets protect against electrical shock and this is very important around water.
AFCI protects against electrical arcs that come from damaged cords and bad connections.  Arcing is super hot, and is responsible for electrical fires.
A combination protection device could be installed in the bathroom, but some people say the combo's don't work quite as well as single purpose GFCI, and arcing fires are generally not a risk in a room filled with tile and other hard surfaces.
Comment: GFCIs protect people. Circuit breakers protect the house's wiring. AFCIs protect the house from faulty end-user equipment, in rooms likely to be occupied for extended periods (especially while unconscious) and with high flammability, +1.
Comment: @Mazura AFCI breakers can prevent in-wall and out-of-wall faults. Both are important.
Comment: "*some people say the combo's don't work quite as well as single purpose GFCI*" Citation Needed.
Answer:
Maybe because arc faults are not more dangerous in those places then in other rooms of a building. The probability of arc faults to go undetected may be even lower in bathrooms, since normally all electric appliances and devices are only switched on if that room is occupied. An arc could be detected by smell, flickering or fume. A fridgerator, A/C unit, laptops and other devices are often running in rooms without a person being present all the time.
No, assuming there is a GFCI and a correct earthing. In that case, an AFCI protection is as indicated as in any other room. In theory, the probability for an arc to occur increases with the water in the air, but a room's air without any water outlet could have a high moisture level as well, dependent on location and weather.
Otherwise, a GFCI is very important in rooms with water and electric outlets, independent on local codes.
Comment: @FreeMan  It is one of my hobbies to demand  mandatory built-in timers in all suited electric devices like ranges, solder irons, hair dryers (deaf users), dish washers, electric  heaters for temporary use, curling irons, toasters (jamming) etc. Only micro wave ovens seem to be only available with timers.
Electric devices w/o those timers (exception are fridgerators etc.)  should no more be produced nor imported. Alternatively a push-and-hold button should be mandatory as available for hotel hair dryers. Besides improving the safety levels, it could help to save energy, too.
Comment: All societies tend to raise the average age, and old people have more memory problems.
Sadly, there seems to be no initiative by all the many national and international  regulatory  bodies  that are responsible for the safety - nor by insurances.
Answer: There is also a disincentive to properly maintain bathroom GFCI equipment if the NEC were to require all receptacle replacements to have AFCI protection.  Leaving this requirement out for bathrooms enables professionals to continue updating bathroom receptacles with life-saving GFCI protection without the cost and concern of changing circuit breakers or other connections.
Answer: The reason AFCI's aren't required in the bathroom is a bit obscure. AFCI's are subject to nuisance tripping, and when people get fed up with the nuisance tripping, they often replace the AFCI/GFCI breaker with an ordinary one, losing the ground fault protection. In a bathroom, the loss of a GFCI is more dangerous than the absence of an AFCI is.
Answer: Without a lot of information I cannot answer this. In my area AFCI is not required but GFCI's are on all outlets if within a 6' of a plumbing fixture such as a sink or faucet. Per my local inspector this is according the NEC (National Electric Code). The best answer I can give you check with your local inspector, in the end that is the person that will approve it.


Should I write "PhD" or "Ph.D."?

Question: Question pretty self-explanatory. Should the abbreviation of the Latin term philosophiae doctor be written as PhD (no periods) or Ph.D. (with periods)?
Comment: You have a couple of correct answers below. Personally I avoid periods in abbreviations, so I would use PhD, just as I would say Washington DC using the postal code abbreviation DC rather than the historical abbreviation D.C. (District of Columbia).
Answer: Actually both are correct. I could easily find both on my NOAD, and there are plenty of pages on the net where you find it written as "PhD".
The OALD gives an interesting distinction, stating that Ph.D. is especially North American English.
Now, being a non-native speaker, I can only rely on official sources to state who uses what, but there's no doubt that both variants are used.
Lastly, I think there's really no point in distinguishing them as "Philosophiae Doctor" or "Doctor of Philosophy" because it's the same exact expression, although considering the abbreviation, the former is the correct and original long version, the latter is just the English translation.
Comment: @MT_Head DPhil is also what a PhD is called at Oxford. If you use DPhil then a BE speaker would assume you specifically mean Oxford.
Comment: Collins English Dictionary shows a separate abbreviation if you want to specify the degree in English: "DPhil".  (Also at http://dictionary.reference.com/browse/phd, just further down the page.)
Comment: @MT_Head: Thanks for commenting. With "if you want to specify the degree in English" you mean "being unambiguous"?
Comment: Indeed. To give an anecdotal example: in the company I used to work for, which was British, people didn't tend to use periods for abbreviations of degrees, e.g. *MSc*, *PhD*. I now work for an American company, where the convention is to use them, hence *Ph.D.*
Comment: I see, I was thinking of that before honestly, since PhD (or PHD) can be other things too... Thanks for pointing it out!
Answer: PhD and Ph.D. are both correct.  Canadians tend to omit the periods and those from the U.S. tend to keep them.
Comment: Might you have any source citations or additional references for that? I think your answer is correct, but a little more detail, doesn't actually *need* to be a link, would be helpful.
Answer: I tend to use both 'PhD' and 'Ph.D'. A DPhil is awarded at both Oxford Uni and Sussex Uni in England. All others award PhDs to my knowledge.
It bugs me when people use 'Dr' before their name and then also state the award following it. I feel it should be one or the other.
Comment: "Oh, I'm going to get some cash out of this ATM machine."
Comment: @hBy2Py : Ha! That's an example of the ironically named RAS syndrome (Redundant Acronym Syndrome syndrome). According to Wikipedia the term was coined in 2001 in a light-hearted column in New Scientist, though I haven't a reference for the original article. On the original question, during my lifetime (started in the 1950s) in the UK there has been a slow but steady move to reduce the use of punctuation and capitalisation in print. This has been driven in part by the newspaper industry, though I can't give any source other than the say-so of journalist friends.
Comment: Agree with Dr being used with PhD part.
Answer: I remember discussing this with a trained secretary a long time ago. We eventually decided that the use of camel case (starting each abbreviated word in upper case) removes the need for the periods when abbreviating titles. However, when an abbreviation is relatively new or used in an unusual context, the periods help to avoid ambiguity.
For my own use, the overriding consideration is 'house style'. It is more important for a document to be internally consistent, to avoid confusion.
Comment: Bobble's "house style" consideration typically applies not just to a single document but also, as the name implies, to all documents emanating from the same "house". For example, my academic discipline (linguistics) traditionally employs the no-periods convention for all titles (not only PhD, MA, and BA but also Mr, Dr, and Prof), while the style enforcer at my academic institution (an American university) insists that I sprinkle periods around (for a total of 9 in my 6 examples).
Answer: As many noted, both are accepted, so it is a matter of convention and taste.
The important is to be consistent with the other abbreviations you use throughout your text. Compare:

I got a Ph.D. in A.I. at U.C.L.A in the U.S.
I got a PhD in AI at UCLA in the US.

My personal preference goes for for omitting periods, given that this is an abbreviation, following the Guardian style guide:

Do not use full points in abbreviations, or spaces between initials, including those in proper names
Answer: The most common I have seen are:

Ph.D
PhD

I have rarely come across a Ph.D. (with two periods).
Comment: Ugh.  _Ph.D_ looks like the inconsistent worst of all worlds.

Should I write "PhD" or "Ph.D."?


Another term or synonym for 'safer appoach'

Question: what can I write other words in place of "safer approach" that will appear nice to read as title.
Context: xyz  a "safer approach for the therapy".
Answer: Usually

a safer approach

to doing something might be described as

a conservative approach
  a traditional approach
  a well-known approach
  a time-honored approach

all four have the implied meaning that the "approach" being used has been tested and used over a longer period of time.  In contrast to

a radical approach
  a new approach
  an innovative approach

Neither set of descriptions implies whether an approach is "correct" or will work only whether is might have been observed to work.


How to find villages in Minecraft PE?

Question: How do villages spawn in Minecraft Pocket Edition? I would also like to know what I need to do to have a village spawn, e.g., if there is any specific biome it has to be in.
Answer: Villagers and villages were added in the 0.9.0 update. If you just want to create a new world with a village in it, you can use the seed 1409511342. You should spawn right next to a village. I believe every generated world will have at least one village in it. Sometimes they may be nearby, or they could be far, far away.
If, however, you want to get a village in a world you have already created, you should be able to find one after adventuring for a while UNLESS the world was created pre-0.9.0. In that case, you should be able to use MCEdit (a PC program) to copy a village from a PC world and place it in your PE world. It's pretty straightforward to use MCEdit, but if your world is 0.9.0+, you shouldn't need to use it.
Comment: I have 1424211818 seed and dropped right next to one as well.
Answer: They are adding villagers in 0.9.0 so there will be villages as well
You can always make your own like mine
Comment: 1 dislike because you said you can make your own but that has nothing to do with spawned villages.

How to find villages in Minecraft PE?


Can someone show by vector means that any inscribed angle in a semicircle is a right angle

Question: Could someone explain how to prove any angle inscribed in a semicircle is a right angle using vectors. I understand that the dot product of two vectors is 0 is they are perpendicular but I don't know how to show this in a semicircle.
Comment: possible duplicate of [Proof of Angle in a Semi-Circle is 90 degrees](http://math.stackexchange.com/questions/776/proof-of-angle-in-a-semi-circle-is-90-degrees)
Comment: (vector proof in the answer by Thomas Belulovich)
Answer: Wlog. we can assume the semicircle to be the upper unit semicircle with centre in the plane origin $(0, 0)$. Let $(x, y)$ be a fixed point on the semicircle with $y>0$.
Consider the vector $v_1$, which is the difference between the positional vectors $(x, y)$ and $(-1, 0)$, and the vector $v_2$, which is the difference between the positional vectors $(x, y)$ and $(1, 0)$.
Now note that the angle inscribed in the semicircle is a right angle if and only if the two vectors are perpendicular. Using the scalar product, this happens precisely when $v_1\cdot v_2=0$.
So just compute the product $v_1\cdot v_2$, using that $x^2+y^2=1$ since $(x, y)$ lies on the unit circle.
Answer: If the semicirce has radius $a$ you can represents the two vectors as the difference between the coordinates of the points $(-a,0)$ and $(a,0)$ with respect to a generic point $(a \cos \theta, a \sin \theta)$ :
$$
\vec v_1=(a\cos \theta -a; a \sin \theta)^T \quad and \quad \vec v_2=(a\cos \theta +a, a \sin \theta)^T
$$
so you have:
$$
(\vec v_2,\vec v_2)=a^2(\cos \theta -1)(\cos \theta +1)+a^2 \sin^2 \theta=a^2(\cos^2 \theta -1 + \sin^2 \theta)=0
$$
Comment: I think using $\sin$ and $\cos$ here is a bit of an overkill.
Comment: hmm... maybe , but it simplify the calculations :)
Answer: Let's consider a semicircle of radius $1$. The semicircle is in the right side of cartesian axes. So all points save for the extremes have positive $X$.
Let $P=(x,y)$ be a point in the semicircle which is not an extreme.
$x^2+y^2=1 \implies x=+{\sqrt{1-y^2}} \implies P=(+{\sqrt{1-y^2}},y)$
The vectors to the extremes are :
Vector to top extreme : $v_t = (0,1) - (+{\sqrt{1-y^2}},y) = ( -{\sqrt{1-y^2}},1-y)$
Vector to bottom extreme : $v_b = (0,-1) - (+{\sqrt{1-y^2}},y) = ( -{\sqrt{1-y^2}},-1-y)$
As you said if the dot product is 0 the angle is right :
$v_t.v_b = ( -{\sqrt{1-y^2}} )^2 + (-y+1)(-y-1) = (1-y^2) + (-y)^2 - 1^2  =  0$
Rotating the semicircle and vectors construction does not change the angle, thus the property of being a right angle is general for all semicircles of radius 1.
Scaling the semicircle and vectors construction does not change the angle, thus the property of being a right angle is general for all semicircles.
Answer: A semicircle is one half circle.  Define 3 vectors r(sub 1), r(sub 2) and r(sub 3). From the center point of the semicircle radiate these three vectors such that say r(sub one) radiates from the center to the leftmost endpoint of the semicircle; r(sub 2) radiates from the center to the rightmost endpoint of the semicircle; and r(sub 3) radiates from the center of the circle to a locus at any point on the circle.  We then know the magnitude of r(sub 1), r(sub 2) and r(sub 3) are equal
Further two vectors, one emanating from the rightmost endpoint to the locus, and one emanating from the leftmost endpoint to the locus will form an angle; an angle which we must prove is a right angle.
Call r(sub 1), r(sub2) and r(sub 3) vectors with origins at the center. The vectors that join the endpoints (of the semicircle) to the locus, let's call U and V (these are all vectors, please keep this in mind). Say vector U emanates from the left semicircle endpoint, and terminated at the locus. Vector V emanates from the right semicircle endpoint and terminates at the locus.
We can then redefine vector U in terms of r(sub 1), and r(sub 3) or U + r(sub  1) = - r(sub 3) and vector V can be redefined as V + r(sub 2) = - r(sub 3) {I THINK} However r(sub 1) = -r(sub 2) ...
And here, I unfortunately, lose it.  We have to show either U dot V equals zero, or the magnitude of U cross V equals one.  I suspect the cross product is an easier proof; but I keep banging my head on the dot product ... I am just a stubborn old coot.
Then by these definitions, r(sub 1) equals -r(sub 2) (Negative r(sub 2).  we can
Comment: The vectors U and V should be situated as U emanating from the left side of the semicircle and terminating at the locus on the semicircle V, should emanate from the locus to the the semicircle (the terminating end of U) and terminate at the right end of the semicircle.  This changes things somewhat.


How can one do dimensional analysis when units are not known?

Question: In the sciences, we can do dimensional analysis and unit checks to verify whether or not the LHS and the RHS have the same units. If we have the following function:$$y=f(x)=x^{2}$$
  what ensures the preserving of units? I have a feeling it is the exponent of 2 which is not dimensionless, but if we write it as:$$y=x^{2}=x\times x$$
  where can I see balancing out of the dimensions?
Comment: What context is this arising in? The square of a scalar is still a scalar, but you can certainly square things that aren't scalars. (And, in purely mathematical settings, one doesn't typically do dimensional analysis. Similar ideas with homogeneity exist, and just generally respecting symmetries)
Answer: If you're doing mathematics, usually you work with dimensionless quantities, so it makes no sense to try to do dimensional analysis.


Why are my attempts to burn TAILS failing?

Question: I attempt to burn the TAILS disk like this:

The result on the disk is this:

and all attempts to boot TAILS fail. Why is this happening and how do I fix it?
Comment: This may be a stupid question, but you did try to boot from CD, right?
Comment: That is correct.
Comment: Click 'verify disc after burning'. What does happen now?
Answer: First make sure your download is not corrupt,
I would reccommend that you try to use use ImgBurn instead of windows dvd burning software.
https://en.wikipedia.org/wiki/ImgBurn , it's a free tool that burns almost any kind of formats to cd\DVD.
Answer: I turned out to be my BIOS settings. The computer went to its pre-loaded OS first. I knew to change them, but I was accidently accessing the startup settings for my default operating system rather than the actual BIOS settings. For anyone who is encountering a similar problem, you should hit the button that takes you to your settings when you see the name of the company that makes the computer, when you see the OS it is too late.


Is there anything against Islam in Hindu texts?

Question: Is the Hinduism v/s Islam fight new or has been going on for generations? Is there a mention of Islam in ancient Hindu texts like the Vedas?
Comment: I think there is a bit mentioned about Prophet in Bhavisya Purana but this purana is said to be highly interpolated
Answer: The Vedas are from about 1500 to 500 BCE. Islam is from the 7th century CE. Hence there is no mention of Islam in the Vedas.
Reference added.

However, it is known from internal evidence that the Vedic texts were orally composed in northern India, at first in the Greater Punjab and later also in more eastern areas, including northern Bihar, between ca. 1500 BCE. and 400 BCE.

Michael Witzel: Vedas and Upanisads in Flood, Gavin (Ed.): The Blackwell Companion to Hinduism (2005).
Hindu scholars somtetimes give much older dates for the Vedas, e.g.,
Dasgupta, Surendranath: A History of Indian Philosophy. Vol.1 1922.
He quotes Max Mueller ca. 1.200 BCE., Haug 2.400 BCE., Bal Gangadhar Tilak 4.000 BCE.
Answer: Hindu scriptures long predate the rise of Islam. I would say that Hindu-Muslim relationship has been bad for many centuries. The 1202 storm campaign of Muhammad Ghori resulted in the destruction of hundreds of Hindu temples. There is no doubt ( in spite of the efforts of secular historians) that Nalanda was destroyed by the Muslim invaders. The common Hindus were forced to pay Jizya tax.
According to some estimates Muslims killed 80 million Hindus in their long 600 year rule. Their rule can be summed up by this quote:

"If the revenue collector spits into a Hindu's mouth, the Hindu must
  open his mouth without hesitation"
  -- Qazi Mughisuddin legal officer of Sultan Alauddin Khilji

(REF:ELLIOT and DOWSON, The History of India, as Told by Its Own Historians; The Muhammadan Period ( 1876-77)).
There was also forced conversions of Hindus by Muslims. An infamous example of a forcible conversion attempt was Aurangzeb's attempt to convert Kashmiri Pundits to Islam in the 1670s. Kashmiri Pundits were saved by the Sikh Guru Tegh Bahadur who was executed by Aurangzeb for defending the rights of non-Muslims to live in India.
Another example would be 16th century Varanasi. Muslim clergy made it impossible for Hindus to live peacefully in Varanasi. Sri Madhusudan Saraswati met Akbar and told him of the plight of Hindus. Akbar told him that he should form  his own forces to resist the Muslim clergy. It is Akbar's advice that led to the birth of Naga Sannyasis.
Will Durant, the famous historian  summed it up like this:

"The Islamic conquest of India is probably the bloodiest story in
  history. It is a discouraging tale, for its evident moral is that
  civilization is a precious good, whose delicate complex of order and
  freedom, culture and peace, can at any moment be overthrown by
  barbarians invading from without or multiplying within."

The Story of civilization by Will Durant
Any other civilization would have been destroyed if they had suffered 80 million casualties. This long unfortunate 600 year old history of Muslim rule throws a long shadow even today.
The present day reality is also unpleasant. Hindu population in Pakistan has declined from 15 % in 1947 to probably about 2 % today while Muslim population of India has increased from 9 % in 1947 to 14 % today thus giving rise to fears. Kashmir valley has seen cleansing of 500,000 Hindus in the 1990s.
Comment: Thats a bigger genocide than Hitler did
Comment: "It is Akbar's advice that led to the birth of Naga Sannyasis.". What is the story of Akbar and Nagas?
Comment: You have not answered the question.
Answer: Speaking of absolute mention of Islam in Hindu texts: there is no such thing.
However, speaking of the concepts, it is clear that any Advaita scholar will be totally in phase with any Non-dualist Muslim. Ramakrishna and René Guénon proved it. Ramakrishna was a Hindu who validated Islam. René Guénon was a Muslim who validated and taught Hinduism even more than he taught Islam in Europe.
The problem is always with the people that misunderstood that there can not be one way to fit every single human. These people won't even accept nuances between people of the same religion, how could you expect them to accept other religions?
They are the test for non-dualists and this has to be accepted as a matter of fact.


What's the difference between AutoCAD and AutoCAD LT?

Question: Want to play with AutoCAD for personal use. Which edition is suggested?
Answer: Here are the differences between AutoCAD and AutoCAD LT.
Answer: AutoCAD is expensive software just for personal use.
I would definitely recommend LT over Full AutoCAD if its just to "play" with. There are only small differences if your main interest is 2D draughting, these differences do not justify the large price jump IMO.
Answer: AutoCAD LT is a mutation of an ancient MS-DOS draughting program, while AutoCAD has 3D abilities tacked on as an afterthought.
If you are starting out with CAD, I would suggest you try learning a modern 3D parametric object based design program instead.  If you wanted to stick with the Autodesk lockin, try Revit for construction or Inventor for mechanical.


Web-based *nix shell

Question: is there any solution like LogmeIn consisting on a small client to install upon a *nix machine and hence being able to use its shell from the browser bypassing proxies because it all will work on :80?
Thanks
Answer: My favourite solution to this is Ajaxterm which I run on an https server since port 443 is rarely blocked and the encrypted stream can't be decoded by firewalls.
http://antony.lesuisse.org/software/ajaxterm/
Comment: If only it worked on an iPad.
Answer: The client doesn't have to run in a browser to use port 80 or 443. Just add a line with Port 80 in /etc/ssh/sshd_config and restart sshd. This obviously requires root or sudo privileges. Then you can connect to the computer using any SSH client, while specifying port 80 (e.g. ssh -p 80 firstname.lastname@example.com).
This solution makes sshd listen on port 80. It will not work if the server runs a web server, of course.
If you rather want port 443, change the port number, or add another line with Port 443.
Answer: Try this solution "MindTerm". I used an early release years ago and it worked pretty well. I configured Apache to use http based authorization when accessing a special url, e.g. "/myshell/" for further protection.
Answer: If your system can connect to the outside using SSH, and you have some other system that's always online, you can create a reverse SSH tunnel.
I highly recommend using autossh for this purpose (after setting up public key authentication), eg.
autossh -M 12345 -f -R 2200:localhost:22 firstname.lastname@example.com

will set up a tunnel where connecting to the remote system's port 2200 will forward to your NAT machine's port 22
Answer: ShellInABox implements a web-based console that can be used for logging in to your system.  All you need is a browser.  From the project description:

Shell In A Box implements a web server that can export arbitrary command line tools to a web based terminal emulator. This emulator is accessible to any JavaScript and CSS enabled web browser and does not require any additional browser plugins.

I've run this myself and it's worked out great.  I only use it occasionally (e.g., when I'm visiting friends/relative and need to log in and don't have an ssh client handy), but it works great even with curses applications like Mutt and Pine.

Web-based *nix shell


How do I override the SQL for a CRecordSet and then requery?

Question: I have a CRecordSet (Visual C++ 6.0) and I'm using ODBC to connect to postgresql 8.0.8.
__
The problem: I insert a row into a table with a serial id (autoincrement), and I would like to retrieve the id after my insert.
I can't use the RETURNING keyword, not supported on this version of PGsql, but I can use currval('sequence').
However, in my code, I need to execute the default query and then override it to execute the query with currval().
From what I understand, I can only override the query by calling CRecordSet::Open() again, which would create a new session, rendering currval() useless.
__
So: How can I override the SQL, then execute this new query via a Requery() and not via Open()?
Answer: As far as I understand, currval() is not connection specific. You should get the correct value back on the new connection. You could also try and append the 'select currval()' at the end of your INSERT statement.
<code>INSERT INTO mytable VALUES (1); SELECT currval('mysequence');
</code>
Comment: currval is connection-specific.
Answer: Use currval().  This is session-specific and concurrency safe.  The syntax is above in Imraan Parker's answer.
The fact though is that with a new session there is no safe way to get this info.


excel 2007 duplicate row

Question: How can I compare records in a table, to make sure these records are not duplicates? Using excel 2007 I don't won't them to delete after comparison.
Duplicates rows should be colored. I have a table columns are from A to P and I have 500 rows. I want to put condition on A, B, E, F, G, I.
Answer: If you don't want to sort your column, you can try with a matrix formula (http://www.stanford.edu/~wfsharpe/mia/mat/mia_mat4.htm).
Practically, you can compare your current row to every row above. Somtething like :
<code>=MIN(LINE(B1)*(IF(A2=A1;1;0))*(IF(B2=B1;1;0)))*(...)
</code>
validated with CTRL-SHIFT-ENTER will check if all the conditions are true, else, will return 0.
Please send a file (with anonymous data) if you want a practical example.
Hope that helps
Edit : here is the good solution (provided you want to compare data in the Q column) :
<code>=MIN(LIGNE($Q$5:Q6)*EQUIV(Q6;$Q$5:Q6;0))
</code>
If you want to have the first line where the value appear
<code>=MIN(LIGNE($Q$5:Q5)*EQUIV(Q6;$Q$5:Q5;0))
</code>
If you'd rather have #N/A if there are no duplicate before that line
Still validate with CTRL-SHIFT-ENTER
Comment: i put all the value from A,B,E,F,G,I columns to a new columns Q. Can i use this formula on this column?       =MIN(LINE(Q5)*(IF(Q7=Q6;1;0))) its not working NOTE* My data start from row 5
Answer: Sort by the columns you are interested in then use a formula to compare each row with the one above. You can then use conditional formatting to colour the results.
Comment: do i have to sort each columns? which i am interested in?
Answer: I may sound stupid here, but usually the simple answers are usually the best.
I did this recently, by literally using the CONCATENATE() function with the TEXT() function to combine all the columns I wanted to compare into a single cell. So in effect I am creating a cell with a unique "key" that holds all the data I want to be unique.
I then sort that column and create another empty column next to it.
Then us this formula to compare the row with the row above it: =IF(A2=A1,0,1)
This simply puts a 0 where it's the same row and a 1 where it's different.
I then filter on the '1's and there are my duplicates!
It'a also usefull as an alternative way of doing a unique COUNT(DISTINCT ...) where I want to count how many unique references of my data exists. SUBTOTAL(3...) is not enough.

excel 2007 duplicate row


Does the Abbott ID NOW coronavirus test return a positive result if you take it while you're still in the incubation period?

Question: It seems like Abbott's ID Now test works by detecting the virus directly as opposed to checking for antibodies? If the test result is negative does that mean you don't have the virus? Or does that not rule out a recent infection with the virus that has not yet reached a level high enough to be detected?
Comment: Welcome to Biology.SE! Please take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site and [edit] your question accordingly. In particular note that personal medical questions are **not** appropriate for this site. ——— We also encourage you to do some research on your own and then, informed by what you have learned, ask any questions you still have (ideally with references to reliable sources). Thanks!
Answer: This is a great biological question! It asks a lot about how empirical science is done in the field of modern biology! I'm glad we encourage such questions from curious people who want to learn more.

It seems like Abbott's ID Now test works by detecting the virus directly as opposed to checking for antibodies?

Yes, the ID NOW test performs a quantitative real-time RT-PCR assay to amplify reverse-transcribed viral RNA, specifically targeting the SARS-CoV-2 RdRp gene.
The product insert for the COVID-19 test for the Abbott ID NOW product describes the "analytical sensitivity" or "limit of detection" (LOD), which describes the true positive rate.
The LOD described in the product insert is the lowest amount of viral genome in the collected sample that you need to get a true positive in 95% or more of administered tests, in units of "genome equivalents per mL".
This is effectively the minimum number of copies of viral genome per mL of assayed sample needed to give a true positive in 95% or more tests. Its LOD (125 copies/mL) is comparable with other tests (example).
A false negative can result if there is insufficient virus copies in the sample, or if there is test material contamination or the test is not performed correctly.
This assay includes positive and negative controls, which help to identify potential problems with how the assay was performed. Controls are important, given the many millions of tests that will be done to identify infected carriers of SARS-CoV-2 — the assay must be done correctly and without contaminants, in order to give the best statistical odds for the correct diagnosis of those who will be tested.


Do historians have responsibility in how they decide to depict something?

Question: Do historians have responsibility in how they decide to depict something?
Isn't it possible that historical interpretations could be utilized for rationalizing e.g. war?
Presumably there's also "propaganda history"?
Comment: Was just listening to 'Detoxifying the Classics' https://www.bbc.co.uk/programmes/m000x72t : "Professor Katherine Harloe asks why racist hate groups are so fond of the ancient world and explores the history of how Classics and white supremacy became entangled"
Answer: Of course. Don't you know your history? ^^
In Rome a hated emperor who had held power could have a 'damnatio memorae' after they die, removing all statues, inscriptions, etc, and attempting a literal removal from the historic record. Which is the converse of the Greek 'kleos', which can be translated as 'everlasting renown' & was of great concern in ancient Greek culture - basically, making it into the stories. Valkyries can personify being chosen for stories in the mead hall of the honoured dead fallen in battle, as can be seen in Darradar's song from the Njal's saga. History has always been political. And it has always been used to bolster narratives and interpretations. Soviet history wiped the records of Stalin's friends that became enemies, even down to very early photographic manipulation. Nazis built elaborate pseudo-histories about 'Aryans', and mythic objects like the 'Spear of Destiny'.
There's a dynamic of better quality history resulting from pursuit of soft power through investing in scholars, or as was saga-tellers, found in many places and times - unlike Nazi pseudo-history this had to convince out-groups as well as the in-group to work. Theological innovation and new churches, orders, cults, pantheons, sects etc very often first of all had to reframe history. And legitimising rulers was a major preoccupation, found in extensive lineages given in old texts like the Bible. Or legitimising systems of governance, political settlements, treaties, boundaries.
History is powerful. Controlling the narrative, can have substantial impacts. Good quality history, really emerged as a set of tools to bolster the authority of a given narrative - with the convenient side effect of preserving as much first hand evidence as possible, allowing later historians to find new narrations that speak to their own times. History draws it's power from speaking to now.
You can compare & contrast different attitudes to history of the colonial powers, and draw some insights. David Hume was more successful in hus lifetime as a historian, than philosopher - at least financially. Churchill won the Nobel Prize for literature for his work on history. People who knew the power of framing the issues. The beginnings of archeology, not to mention natural history and anthropology, are found in a blur between a grand-tour and serious scholarship. Drawing a link between Greece and Rome, and the British Empire, allowed a totally spurious sense of cultural continuity. So you end up with the Uffizi being basically heaps of unlabelled cultural history, while the Victoria & Albert Museum is a carefully labelled palace of history.
Good history, uses the contention over narrative, to foster Socratic dialogue - mutual open-ended curiosity about finding better answers. We never have definitive final accounts of history, each generations instead decides what to keep alive, what to ignore, what lessons or insights there are, to guide us into the future. History is a living text, and we cannot hope to escape our own time and it's circumstances in our history, for all the processes we apply to establish facts well, consilience of evidence etc. But nor should we, history shouldn't, can't be, a dead record. It has to be about what speaks to us.
Do historians have special responsibilities? I'd say above all they should have in mind, how history will remember them. Propagandists and distorters won't be remembered well - except the ones who were so good they never got caught, and now we see things the way they wanted.. There are ever more records, so it's ever harder to pull that off. So doing a good job is a better way to be remembered. The historian that loves war might treasure leaving a history that started one. A peacemaker, the converse. Above all, they should be pursuasive, and try to speak beyond their constraints of group, and time - knowing they will fail, and keeping future historians in a job.
Comment: Outstanding, sir.


Autoregressive coefficients and heteroscedasticity

Question: The estimated parameter in an AR (1) with just one dependent variable is 0.92. I have checked the residuals for heteroscedasticity and both the Breusch-Pagan test and the White test confirm the presence of heteroscedasticity. Does this affect the reliability of the estimated parameter? Can I still confirm that the time series is AR (1) with an Autoregressive coefficient of 0.92?
Comment: I was going through my old answers and noticed this one was not accepted. Do you perhaps need further clarification?
Answer: If you used OLS or conditional least squares, your estimate is still consistent although biased (but bias is hard to avoid for autoregressive models).
More importantly, it is inefficient due to the heteroskedasticity. But that does not necessarily mean you can do better (that a feasible efficient estimator exists).
In any case, you cannot "confirm" the estimate is exactly 0.92, but you could obtain a confidence interval around your estimate (using some heteroskedasticity-robust variance estimator) and phrase your conclusion in probabilistic terms.


Higgs boson in LHC

Question: Recently, the Higgs boson was discovered in the LHC. My question is:
How did they come to know that the particle created was actually the Higgs boson?
On the basis of which properties did they confirm it as the Higgs boson?
Comment: It's not technically confirmed yet.
Answer: The experiments have measured the number of events in which the Higgs boson was produced and decayed into various final particles such as a pair of photons; pair of Z bosons; pair of tau leptons; bottom quark-antiquark pair, and a few others. All these numbers are compatible, within the current error margin, with the prediction of the Standard Model Higgs boson (the diphoton decay rate may be currently higher by 70% or so and it hasn't been fully updated, but all the others are currently "totally well-behaved").
There are specific polarization-based experiments that show that the particle is almost certainly a scalar, not a pseudoscalar, and it must have spin $j=0$.
If the particle were a "completely, qualitatively different" particle than the Higgs boson, the numbers of events mentioned above would differ from the Standard Model Higgs values (theoretically calculable and experimentally measured) by a lot, typically by many orders of magnitude. So it's clearly "something like the Higgs boson". Moreover, a Higgs boson is needed for the Standard Model to be consistent.
At this moment, it remarkably barks like the SM Higgs boson and does everything else like one, too. At the current accuracy, we may see it is the Standard Model Higgs boson. In fact, our accuracy and certainty that it is so is no longer too different from the certainty with which we may say that what we call the W-bosons are W-bosons and what we call the Z-bosons are Z-bosons. If you were impartial, you should have asked the same doubtful questions about the W-bosons or Z-bosons or other particles, too. The Higgs boson is a newer particle but it's already a part of the standard collection that agrees with the Standard Model so well that it can't be quite a coincidence.
The fact that the discovered July 4th Higgs boson behaves just like the Standard Model Higgs boson is increasingly clear and increasingly frustrating because it gives us no hints how to go beyond the Standard Model so far. See stories such as

http://articles.timesofindia.indiatimes.com/2012-11-19/science/35204514_1_higgs-boson-standard-model-higgs-british-physicist-peter-higgs

Sometime in the future, perhaps distant future, new physics will be discovered, e.g. new particles, and they will modify the whole theory including the identity of the Higgs sector. But they will slightly modify the Z-bosons, W-bosons, and all other particles as well. In some sense, it will be proved that they're not the Standard Model Z-bosons or W-bosons, either. It makes no sense to single out the Higgs boson (although when it comes to the Higgs, there are best reasons to think it has "siblings"). The whole theory will ultimately be shown to differ from the Standard Model.
At this moment, however, once again, all the observations at the LHC agree with the Standard Model which is why it is legitimate to use the Standard Model terminology for all the particles and interactions we're observing.
Answer: They know the particle is a Higgs boson because they trace the decay products. If there is a slight increase in one type of particle. Lets say it the bottom-antibottom pair then this might be clue that the Higgs boson was discovered. Especially if they see this bump over and over again. There has to be a Higgs otherwise not only will the theory of how fundamental particles get mass fall to bits, but the electroweak theory will also crumble. The Higgs just fits so well into the standard model. They have tested for the Higgs by the decay products and it turns into a pair of bottom quarks(one bottom and antibottom) ranging to double Z boson decay. This is how they know the Higgs is what they found. The Higgs boson is a spin zero particle sort of like the Z boson. It is a little heavier for the most part.

Higgs boson in LHC


Copyright issues when journal is defunct

Question: Consider a seminal paper published 40 years ago in a journal that went belly up 30 years ago. Many cite it but hardly anyone has seen it. Can I expect trouble if I make an electronic copy available on my blog?
Comment: In what jurisdiction was the paper published? What is the exact *year* of publication? In some jurisdictions, copyright law has changed over time, and if you're talking about the US, copyright law changed significantly in 1976 (effective Jan 1 1978), which is close to the vague "40 years ago" timeframe you're talking about.
Comment: This question could also be a good fit in Academia.SE. I assume the author wanted a legal point of view instead of an academic one. In case someone misunderstood me, I'm not advocating (ha!) for a migration.
Answer: Factual assumptions
ohwilleke's answer is entirely correct. However, it makes factual assumptions based on the standard meaning of "journal" and "author", which I believe to be unwarranted. From the question, it seems likely that we are talking about a scientific paper, which operates under a very different economic and legal model.
I am going to assume that:

the authors sent a draft of the paper, the preprint, to the journal editor;
the journal editor sent the draft to external experts (the reviewers); those reviewers, and possibly the editor, gave some feedback;
the authors modified their draft based on that feedback to produce the final version;
throughout all this, the authors, editor and reviewers agreed with the journal's policies;
the journal policies require a transfer of copyright to the publisher, a legal entity that "owns" large number of journals and provides some technical services (article typesetting, maintenance of a web site with the journal contents, maintenance of DOIs, etc.);
neither the authors, nor the editor, nor the reviewers received monetary compensation for their work (this is a key economic difference from non-academic journals, but as we shall see, it has little legal effect)

In theory, all depends on the copyright release agreement
When the author(s) submit a draft to a journal, they have to click through an agreement to release copyright. Such a clause could, in theory, be anything the authors and the publisher agreed that does not violate contract law. In practice, because the publishers are a small oligopoly, the agreements are more or less standardized.
The "sample publishing agreement" given as example at https://www.elsevier.com/about/policies/copyright (as downloaded on March 2, 2023) is more or less representative:

I hereby assign to the Copyright Owner the copyright in the manuscript identified above (where Crown Copyright is asserted, authors agree to grant
an exclusive publishing and distribution license) and any tables, illustrations or other material submitted for publication as part of the manuscript (the
"Article"). This assignment of rights means that I have granted to the Copyright Owner the exclusive right to publish and reproduce the Article, or any
part of the Article, in print, electronic and all other media (whether now known or later developed), in any form, in all languages, throughout the world,
for the full term of copyright, and the right to license others to do the same, effective when the Article is accepted for publication. This includes the
right to enforce the rights granted hereunder against third parties.

The authors are the sole intellectual contributors to the preprint version, but a copyright release agreement could still bar them from publishing it. The vast majority of agreements between novel authors and publishing houses forbid the author from selling the book rights to another publisher or posting drafts of the novel on the author's website (two actions that would result in greatly diminished sales for the publisher).
The published version incorporate revisions where the reviewers and possibly the editor contributed significant intellectual contributions. Again, all depends on the copyright agreement - the publisher terms could in theory require that the reviewers and editors release their contribution under an irrevocable license to the authors. In practice, all goes to the publisher.
The financial structure is irrelevant
The fact that authors (and reviewers, and editors) are not paid by the publisher is irrelevant. Yes, a contract (in common-law countries) requires consideration from both sides; however, consideration needs not be monetary.
There is not much doubt that publication of an article is "consideration", at the very least because that is considered prestigious among a significant fraction of the population. In addition, there is ample evidence that funding agencies and university HR staff evaluate and promote scientists based primarily on the papers they publish in scientific journals.
In practice, preprint rules are lax
The vast majority of academic publishers allow authors to publish the preprint version although conditions vary (only the preprint, only on a personal website, only for a limited time, only after some embargo period, only if you cite the final article with the correct DOI, etc.).
I would speculate that this is the result of cultural pressure. Many academics decided to post their articles (sometimes the preprint before sumbission, sometimes the published version) on the internet without much regard to pesky questions of copyright law, because they viewed publishers as gatekeeping greedy monopolistic parasites. The publishers decided to embrace the practice in order to be able to put some limits on it, rather than try to mass-fire lawsuits against the people who provided them with free labor.
Regardless of whether that speculation is correct, the current arrangement is not the inevitable result of legal rules, and publishers could conceivably decide to change their preprint sharing policies at any moment.
Limitations to the copyright of research papers
This section is quite obviously not exhaustive, but given that the original question does not specify a jurisdiction, I did not search beyond what I already know.
In the united-states, works produced by employees of the federal government as part of their work duties are generally public domain (17 U.S. Code § 105; do note that subsection (b) means certain works produced by certain institutions still are under copyright). Hence, if the authors were both researchers at a federal research institution, the preprint is public domain and can be republished irrespective of the publisher's will. (I am led to believe, however, that most US researchers are not employees of the federal governments, but rather of private or state universities.)
In europe, as a result of public pressure against publishers (see "greedy monopolistic parasites", above), the European Commission published non-binding guidelines (2012/417/EU) asking that

there should be open access to publications resulting from publicly funded research as soon as possible, preferably immediately and in any case no later than 6 months after the date of publication, and 12 months for social sciences and humanities

That (non-binding) recommendation has been adopted with varying adaptations in various EU countries. The exact implementation in a given country should be checked before relying on it. For instance, in France, article L533-4 du code de la Recherche allows authors (after the six or twelve months embargo period) to post the published version (not just the preprint), irrespective of what what signed with the publisher, as long as at least half of the funding for the research came from public funds.
I will assume neither of those apply.
The copyright owner is likely still around
Academic journals are born and die regularly. However, academic publishers rarely do (Elsevier is almost 150 years old).
As ohwilleke says, the copyright release contract signed 40 years ago is likely still valid; even if the publisher folded, it would apply to the publisher's legal successor. (The question of how legal rights are liquidated in a bankruptcy would be an interesting question that I am not competent to answer; it is plausible that under certain circumstances the contract would be dissolved.)
If the authors can access the copyright release they signed back when they submitted the article, you might be able to determine that posting the preprint or the final article is acceptable. (I realize that this is a fairly ludicrous hypothetical, given that the paper was published 40 years ago.)
Otherwise, it is extremely likely that the publisher would be able to sue, even if the publication occurs with the authors' full support. Whether they are likely to do so, and whether publishing anyway is ethical, are of course non-legal questions.
Comment: The odds of being sued are very difficult to estimate, but for the OP it might already be helpful to know what the kinds of damages would be if successfully sued as an individual for publishing a single paper. @KFK Do you have any ideas about that? If I was the OP that might influence my willingness to take the risk.
Comment: @user2705196 The worst-case scenario includes criminal liability as well (https://en.wikipedia.org/wiki/United_States_v._Swartz). That's of course extremely unlikely.
Comment: This is a great answer as it provides a lot of good background to explain why the copyright holder might still be around (and not be the authors).
Comment: I believe one reason for the publishers' approach is pressure caused by governments that make rules that force grantees to make sure their papers are publicly accessible.
Comment: @KFK Good point, but worth keeping in mind that Aaron Swartz was never charged with copyright violations but with "wire fraud, computer fraud, unlawfully obtaining information from a protected computer and recklessly damaging a protected computer". It is of course true that many people consider the CFAA to be phrased so broadly that it can be used to charge anyone for anything involving a computer on a network... But I'd say in the OPs case I'd definitely focus on the copyright violation and what the civil damages would be that a publisher could sue for publishing one of their articles.
Comment: To add to your section about copyright exceptions: research grants given out by US government organizations to private entities sometimes come with a requirement that the resulting data and papers be made freely available to the public (since those grants come from public tax revenue).
Comment: @user2705196: Note that, since the Swartz case, the Supreme Court has [significantly narrowed](https://www.oyez.org/cases/2020/19-783) the scope of the CFAA by statutory interpretation. In general, the new interpretation is not compatible with charging a person merely for violating terms and conditions. I'm skeptical that Swartz could have been charged under the current interpretation, but the breaking-and-entering part complicates things.
Answer: united-states
The unavailability of the journal that published an article or the author is not a defense to copyright infringement. U.S. law does not recognize an "orphan works" exception to copyright infringement. The copyright probably belongs to the author or the estate of the author of the article rather than to the journal in any case. And, a copy of 100% of an article made available to anyone on the Internet, even if not for profit and for educational purposes, probably doesn't constitute fair use.
So, if you were sued for copyright infringement, you would probably lose.
Whether the author, or the author's estate, or the journal are likely to sue you for doing so is another matter. It probably isn't very likely, but there are no guarantees. And, if you were sued, full statutory damages and attorney fees would probably be available to the person suing.
Comment: @Trish Incorrect. Non-open access articles generally require a full and permanent transfer of copyrights. This is more strict than books, where copyrights may revert to the author when the book is out of print. Example, [IEEE](https://www.ieee.org/publications/rights/copyright-policy.html) "Prior to publication by the IEEE, all authors or their employers shall transfer to the IEEE in writing any copyright they hold for their individual papers.". [Elsevier](https://www.elsevier.com/__data/assets/pdf_file/0007/55654/AuthorUserRights.pdf) "Elsevier requests a transfer of copyright" [for non-OA]
Comment: @Trish wouldn't the copyright to that version (as well as all others)  be transferred to the publisher?
Comment: Yes, I want to second @user71659's point: many scientific journals take the copyright from the authors and will not publish the work unless the authors sign over their copyright. This is not rare (although it has been changing somewhat recently).
Comment: @user71659 The exact opposite is usus in Germany, but they demand a quite lengthy exclusive license.
Comment: Thank you very much for answering. I forgot to mention that the authors are alive, well and consenting, I was wondering about the possible owners of the defunct journal. (PS your cat is the spitting image of mine).
Comment: @GeorgeWhite Generally no. Scientific journals rarely want copyright in articles.
Comment: @Trish Germany has exceptionally strong moral rights for authors (compared to publishing as a whole), which can't be transferred, and which I suspect will be a driving force for the difference.
Comment: @IAP if you contact the author you can get the original text and publish *that* in your own formating, without touching copyrights the journal held in the format
Answer: If you're in the US, try searching the article in question in the catalog of US Copyright Office.
Works which are registered with the copyright office have a stronger protection against infringement: the plaintiff doesn't have to prove that he suffered actual losses or damages and sue you for statutory damages instead, which is between $750 and $30000 per work, and could be even higher in some cases.
If the article you want to share is not registered, the risk becomes significantly lower, as proving that a defunct journal has suffered profit losses due to your infringement will simply not be worth it. You can still be sued in theory, but in practice a reasonable copyright holder will just send you a takedown request and won't bother to sue if you comply.
PS. Remember that none of the answers here constitute actual legal advice.
Comment: Again, not legal advice, but if it's not registered, they can only sue you for _actual damages_, which is a legal term-of-art that means they have to demonstrate that your distribution of the paper actually caused them some sort of harm, either directly or indirectly. They would have a hard time trying to explain to the court what sort of losses they suffered on a paper that has been out of print for three decades. Again, not a lawyer, not legal advice.
Answer: I am aware of analogous problems in my own field, which arose from legally-sloppy practices. The fundamental question is what license the author gave to the publisher. Some academic publishers are well-organized profitable businesses, some are not (they may not be businesses in any sense). In the latter case and especially for a work created in the early 80's, the odds are high that no explicit license was granted, in which case at most a court could find that the publisher was granted a non-exclusive license to distribute. The first question then would be, what license / transfer did the author grant (does the author even remember? or keep a copy?).
Assume that the author transferred copyright to the publisher (more probable with a well-organized profitable business publisher). The journal "going belly up" could mean that the publisher stopped publishing the journal but is still in business; or, the publisher went belly up. If copyright was transferred to the publisher, then the publisher or publisher's successor could sue you for infringement, assuming they can prove that copyright was transferred. If the work was only licensed, not transferred, and if the author grants you permission to distribute, that is the end of the matter.
It is entirely possible that transferred copyright can lie dormant for decades (the publisher went out of business and nobody tried to auction off the copyrights to the works published) – until one day something happens (somebody dies, a folder with copyright transfers is uncovered, and the rights were sold to a big commercial publisher). Now you face a threat from a new owner of the copyright. Without a good historical account of the author and publisher, there is a danger of a copyright infringement lawsuit.
One solution to the distribution problem is to have it available via a library or archive which is allowed to make copies, under 17 USC 108, which says that

it is not an infringement of copyright for a library or archives, or
any of its employees acting within the scope of their employment, to
reproduce no more than one copy or phonorecord of a work, except as
provided in subsections (b) and (c), or to distribute such copy or
phonorecord, under the conditions specified by this section, if— (1)
the reproduction or distribution is made without any purpose of direct
or indirect commercial advantage; (2) the collections of the library
or archives are (i) open to the public, or (ii) available not only to
researchers affiliated with the library or archives or with the
institution of which it is a part, but also to other persons doing
research in a specialized field; and (3) the reproduction or
distribution of the work includes a notice of copyright that appears
on the copy or phonorecord that is reproduced under the provisions of
this section, or includes a legend stating that the work may be
protected by copyright if no such notice can be found on the copy or
phonorecord that is reproduced under the provisions of this section.

There is a legal way to get what you want, without you doing it. Not an endorsement, but Hathi Trust solves may of these "out of print" problems.


Why would the iPhone constantly remind for google calendar entries?

Question: My wife finds that her iPhone constantly reminds her of google calendar events (accessed via the exchange trick). None of the google events have reminders enabled. The phone preferences don't ask for reminders. Yet reminders she gets.
Answer: By default Google calendar is configured to send notifications for events. Go to http://calendar.google.com/. Select the Calendar Details -> Notifications. There is an option 'By default, remind me via...'. Click on the remove link to get rid of the default notification.
Comment: Nope, been there, done that. No notifications are defined. And, in any case, the pesky notifications only show up on the phone.


What is "SPIislatency" in response headers of SharePoint online

Question: Can you please explain what is the use of SPIislatency in response headers of SharePoint Online. I am trying to understand the performance tuning concepts of SharePoint Online.
Answer: SPIislatency is the time in milliseconds taken in the front-end Web server after the request has been received the front-end Web server, but before the Web Application begins processing the request.
This value is stored in partitioned tables for the RequestUsage logging provider. This view can be queried to return data pertaining to all client web requests that have been made since the beginning of the retention period.
As per my understanding Response Headers can only be removed using an HttpModule. Since its SharePoint Online that option is not feasible.
Comment: Thanks for the reply. I totally agree that we can modify or remove since its online version.
Comment: I wanted to comment on this in case anyone finds their way here while searching. SPIisLatency is only one metric to understanding page performance and tuning. There are others. For a breakdown of the metrics and what they mean, I'll refer you to my blog post on the topic: https://sharepointinterface.com/2017/07/07/the-five-minute-page-performance-troubleshooting-guide-for-sharepoint-online/. Also, the Page Diagnostics Tool for SharePoint provides access to these performance metrics: https://chrome.google.com/webstore/detail/page-diagnostics-for-shar/inahogkhlkbkjkkaleonemeijihmfagi?hl=en


FME in task scheduler fails to get ESRI license

Question: We have FME2016 and an ArcGIS 10.3.1.  I am trying to run a task in task scheduler that writes to either a file geodatabase or an ArcSDE enterprise database. This has been successful until about 2 weeks ago when the ArcGIS license manager was updated to ArGIS 10.3.1. from 10.2.1. and FME started showing the following messages in all of the FME log files during a task scheduler run:
"The Esri Product license used by this machine does not include licenses for the 'Engine Enterprise Geodatabase' licensing level
The Esri Product license used by this machine does not include licenses for the 'ArcInfo' licensing level
The Esri Product license used by this machine does not include licenses for the 'Engine' licensing level
|ERROR |Unable to perform licensing related tasks. Please ensure that ArcGIS is correctly installed."
The ArcGIS Administrator does show that licenses are available and is pointing to the correct license manager. The task scheduler settings are set to 'Run with highest privileges'.
We are thinking this has something to do with permissions settings in task scheduler because the same FME workbenches run successfully when the application is open and manually run.  Attached is a screenshot of the task scheduler settings.
Has anyone else run into a similar issue?
Comment: UPDATE:  FME support staff figured this out for us.  We had to add a new environmental variable (through Windows system settings) as 'ARCGIS_LICENSE_FILE' and set its variable value to (port)@(host) of our license manager.
Comment: Find out what user account the workbench runs under, then start the workbench interactively by choosing "Run-As" and see what happens. http://www.sevenforums.com/tutorials/419-run-different-user.html
Comment: Thank you for the suggestion. Right now the workbench runs fine if I open the FME application and hit 'run' while logged in with my windows login, which is the same settings set for the task scheduler.  I've also tried setting task scheduler with a windows admin account, no luck.  Right now we are looking in to getting FME server to schedule tasks, but it would be great to find a solution with task scheduler.
Comment: Go ahead and provide this as an answer your own question so that people with the same question can more easily find an answer.
Comment: Almost there, click the checkmark to accept the answer.  Yes, I know, it does seem a bit vain, but it really is for the good of the community.
Answer: Ensure the Windows advanced system settings on a local client (not on the server side) has an environmental variable named 'ARCGIS_LICENSE_FILE' and is set to (port)@(host) of the server that has the installed ESRI license manager.
This is also documented here:  http://resources.arcgis.com/en/help/install-guides/license-manager/10.1/index.html#/Defining_port_host_to_one_or_more_license_servers/00790000000t000000/


Granger causality test

Question: How best can I use the Granger causality test in time series data and understand it better because I have never used it. I want to analyze long run relationship and bi-directional relationship between two variables.
Comment: @Andy edited in the granger-causality tag, which shows that there are lots of questions on the topic on this site. Have you looked at any of them? Are you sure you have a new question? Have you studied basic texts and internet sources?
Comment: from the few sources I have looked at, the model seems to be written different and the are barely describing the letters on the model
Comment: I don't think I understand that comment. However, you seem to be asking for a personal tutorial starting from scratch on what in its field is an utterly standard topic. You may be lucky, but a common attitude from many people here will be "Please do read a textbook at your level".
Comment: will try to get to books thou I just wanted a little understanding especially on interpreting the symbols on the model
Comment: Daniel, why don't you try writing out the model (using the notation from the texts) and ask specific questions about the symbols you are puzzled by?
Answer: Here is an off the cuff answer.
Granger causality means that the shock or error from one variable has a cross correlation or impacts another.
H0 or the null hypothesis is NO CAUSALITY. It means your result falls within a range or confidence interval close to zero significance.
If the p>.05, the probability you 'struck out' and the one variable does not impact the other is high enough you 'cannot reject the null of no causality.' Stats-speak: you must accept that you failed to show causality on the variable.

Granger causality test


How to upload video into wowza while i shoot from iphone and link it to parse using swift?

Question: I am pretty new to wowza and for my app, I am using Parse as a backend. i have worked out a way to upload a video to parse after it is shot but now i need to upload it so it is LIVE. I heard that wowza is a good option to do that. So how do I do it ?
Answer: Convert AV to a format Wowza works with
If you can convert the uploaded format into something wowza can ingest (rtmp or rtsp, ffmpeg might be handy) you can transcode it into HLS format.
<code>ffmpeg -re -y -i <input> -strict -2 -f rtsp -muxdelay 0.1 <rtsp route>
</code>
where input is source video, and rtsp route is of the form rtsp:/someIP/app-6093/d8d26f76 and references your transcode/wowza IP