How to remove WLAN Configuration Software

Question: I have with me Wireless adaptor. After first time installing it i have removed it from computer without add or remove program by simply right click delete. Now i am installing again but at the time of installation it shows one message "Another WLAN configuration software exist in your system. That could cause problem. Please Uninstall it first". I have removed some registation keys as per u suggested. Still at the time of installation that error continues. Please suggest me what to do.
Answer: Reinstall the wireless program that is causing the problem. Then uninstall it properly.


Cisco Unity call manager - deleting users within an LDAP setup

Question: We have just installed VOIP on the network and AD has been setup to sync with the CUCM which works just fine at the moment. However I need to delete a user from the CUCM (user no longer requires a phone but is still an employee) but am currently unable to do so - I get a message stating that "the add delete functions have been disabled because the user directory is in sync with LDAP".
What I need to know is what options, if any, do I have for deleting a user from CUCM without deleting the account from AD.
Would the operation be immediate or or there a time factor involved.
Also what happens to the CUCM user accounts in general if I disable an AD user account.
Answer: I'm way late, but ran into this the other day.
The only way to get them out of CUCM is to delete them in AD, ore remove their last name in AD.  You can delete the phones/device profiles, but not the users.


Only navigator shows changes in Illustrator CC 2015

Question:
Pretty much you can see that this line won't show visual change. When i try to change the stroke it shows only in the navigator bar but o
Answer: You are looking at the "View Outline". You must have pressed the shortcut by accident.
To view all artwork as outlines, choose View > Outline or press Ctrl+Y (Windows) or ⌘+Y (macOS). Choose View > Preview to return to previewing artwork in color.


Infinitely expandable binary decoder circuit

Question: I tried to make some binary to decimal decoders, but I had no idea how to build them, so I ended up using the "combination checker" (basically providing one checker for each number). That was really inefficent and almost impossible when decoding e. g. 32-bit numbers (4,294,967,295 combinations). So I want to ask, is there some logic pattern you build over and over? Or should I make a separate arithmetic unit for calculating  this the mathematical way? I want my output to be for example 7 segment display. And one more question, how does this decoding work on normal computers? Thanks for help
Comment: It's not clear from your question how this is to work. You want a 32-bit input but how many outputs? Are you looking for a particular number or all numbers. If the latter then you need your 4 billion outputs. Please edit your question to explain. You can insert a diagram with the schematic tool.
Comment: I edited the question.
Answer: you could build a chain of divide-by-ten circuits and tap off the remainders.
Answer: The "combination checker" is the fastest since it requires only two levels of gates.
A slower but with low gate usage can be implemented with successive 1:2 demultiplexers. To add a lsb from N level to N+1 level use N input 1:2 demultiplexer driven by the newly added lsb
Here the demultiplexer is implemented using one shared NOT gate and two AND gates
You cannot expect a 4,294,967,295 outputs logic to be simple.
If you don't need all combinations you can skip the gates with outputs that lead to only not used outputs.
Take care this solution has a high hazard!

simulate this circuit – Schematic created using CircuitLab


What are the consequences of not upgrading to the latest version of java?

Question: Suppose I need to convince someone to upgrade to the latest SDK version of Java? I have heard there are many security vulnerabilities with old versions of java but can't find anything that concretely convinces me that this is the case? What are some hard consequences or security exploits that exist for old versions of java?
Comment: [Related question and answer](http://security.stackexchange.com/questions/67596/why-is-it-a-security-problem-not-to-update-ones-browser/67599#67599)
Comment: Do you mean the latest within a supported major version? Or to the latest major version?
Comment: Most of the security holes apply only if the java browser plugin is enabled, since it allows an untrusted applet to execute arbitrary code.
Answer: There are a number of them, including those that allow arbitrary code execution.
From Qualys, on January 20 (last week as of this writing):

Java: 19 vulnerabilities addressed in Java 8 and Java 7, 13 are remotely exploitable with highest score CVSS 10. This should be high on your list for your patching efforts, at least on the desktop where most of the vulnerabilities are aimed at. Only four vulnerabilities also apply to servers.

CVSS 10 means:

they can be used to take control over the targeted machine, working remotely through a network and without requiring credentials

Precisely how these recently-patched vulnerabilities can be exploited, and their official names, isn't mentioned - assuming they have official names, as Qualys suggest they may include 0-day exploits. Oracle isn't giving many specifics.
Another, older vulnerability from 2013 also allows arbitrary code execution, via an Applet:
https://www.us-cert.gov/ncas/alerts/TA13-051A
So, the big risk is complete control of the target machine.
For end users, arbitrary code execution on their machine may result from loading a malicious Applet.


Integral $\int_0^{\pi/2}\frac{x}{\sin x}\log^2\left(\frac{1+\cos x-\sin x}{1+\cos x+\sin x}\right)dx$

Question: Please help me to evaluate this integral:
$$\large\int_0^{\pi/2}\frac{x}{\sin x}\log^2\left(\frac{1+\cos x-\sin x}{1+\cos x+\sin x}\right)dx$$
Comment: It might help to note that $$\frac{1+\cos x-\sin x}{1+\cos x+\sin x}=\tan \left(\frac{\pi}{4}-\frac{x}{2} \right)$$
Answer: Your integral can be expressed in terms of certain special functions:
$$\begin{align}
\int_0^{\pi/2}\frac{x}{\sin x}\log^2\left(\frac{1+\cos x-\sin x}{1+\cos x+\sin x}\right)dx&=\frac{\,\pi^2}6K+4\,\beta(4)\\&=\frac{\,\pi^2}6K-\frac{\pi^4}{24}+\frac1{192}\psi^{(3)}\left(\frac14\right)\\&=\frac{\,\pi^2}6K-\frac{119\,\pi^4}{2880}-\frac1{32}H^{(4)}_{-3/4},\end{align}$$
where
$K$ is Catalan's constant, $\beta(x)$ is the Dirichlet beta function, $\psi^{(n)}(z)$ is the polygamma function and $H^{(r)}_n$ is the generalized harmonic number.
Comment: I got this result semi-manually, with a help from _Mathematica_. I'll try to write a proof later.
Answer: I have been dabbling with this one off and on and thought I would post some results.
L.T., may I ask where you found this monster?.
Using Integrals idea of using $\displaystyle \frac{1+\cos(x)-\sin(x)}{1+\cos(x)+\sin(x)}=\tan(\frac{\pi}{4}-\frac{x}{2})$, one can make the sub $t=\tan(\frac{\pi}{4}-\frac{x}{2})$ and obtain:
$\displaystyle\pi\int_{0}^{1}\frac{log^{2}(t)}{1-t^{2}}dt+4\int_{0}^{1}\frac{\tan^{-1}(t)log^{2}(t)}{1-t^{2}}dt$.
The leftmost integral is rather famous and evaluates to $\displaystyle\frac{7\pi\zeta(3)}{4}$
The other one is the one that is the booger. It evaluates to $\displaystyle\frac{\pi^{2}}{24}G+\beta(4)-\frac{7\pi\zeta(3)}{16}$
So, using the integral form of digamma:  $\displaystyle\int_{0}^{1}\frac{1-t^{a-1}}{1-t}dt=\psi(a)+\gamma$, along with the arctan series, diff this twice w.r.t 'a' in order to introduce the $log^{2}$ term. Make the sub $y=t^{2}$
$\displaystyle1/2\int_{0}^{1}\frac{y^{n+a/2-1/2}}{1-y}\sum_{n=0}^{\infty}\frac{(-1)^{n}}{2n+1}dy$
$\displaystyle=\frac{1}{8}\sum_{n=0}^{\infty}\frac{(-1)^{n}\psi''(n+1)}{2n+1}$,  by noting that a=1.....................................[1]
By using the identity $\psi(x+1)=\psi(x)+1/x$, one may write:
$\displaystyle\frac{1}{8}\sum_{n=1}^{\infty}\frac{(-1)^{n}\psi''(n)}{2n+1}+\frac{1}{4}\sum_{n=1}^{\infty}\frac{(-1)^{n}}{n^{3}(2n+1)}-\frac{\zeta(3)}{4}$
where the n=0 term was brought out of the digamma sum due to the identity not being defined there.
The middle series is equal to $\displaystyle2-\frac{\pi}{2}-log(2)+\frac{\pi^{2}}{24}-\frac{3\zeta(3)}{16}$
Thus, giving $\displaystyle\frac{1}{8}\sum_{n=1}^{\infty}\frac{(-1)^{n}\psi''(n)}{(2n+1)}+2-\frac{\pi}{2}-log(2)+\frac{\pi^{2}}{24}-\frac{7\zeta(3)}{16}$
I tried writing the sum in terms of its odd and even componets. At least, to eliminate the alternation.
$\displaystyle\frac{1}{8}\sum_{n=1}^{\infty}\frac{(-1)^{n}\psi''(n)}{2n+1}=\frac{1}{32}\sum_{n=1}^{\infty}\frac{\psi''(2n)}{n+1/4}-\frac{1}{32}\sum_{n=1}^{\infty}\frac{\psi''(2n+1)}{n+3/4}+\frac{\zeta(3)}{12}$
This is as far as I got.  If anyone knows how to evaluate an alternating tetragamma series, please, I would love to see it.
I have found little work done on these. May be a good topic for a paper. :)
EDIT:  Due to the identity $\displaystyle \psi''(n+1)=-2\zeta(3)+2H_{n}^{(3)}$, we may write the digamma sum in [1] as:
$\displaystyle \frac{1}{8}\sum_{n=1}^{\infty}\frac{(-1)^{n}\left[-2\zeta(3)+2H_{n}^{(3)}\right]}{2n+1}-\frac{\zeta(3)}{4}$
As a side note, The only other problem I have encountered that has the $\frac{\pi^{2}}{6}G$ term is this one:
A double series yielding Riemann's $\zeta$
Maybe this integral can some how be connected to series like this?.
Comment: THE PROBLEM HAS BEEN SOLVED USING CONTOURS AND THE DIGAMMA KERNEL.


Firefox for Raspi

Question: I have a personal preference for FF - mainly because I use it on the Mac's I have
But in my ignorance I am unsure whether it is "safe" to install on Pi4 under Raspi.
Comment: You should probably put your RPi in a Faraday cage and do not connect anything if you want to be "safe".
Comment: Pretty sure the dark army can still do things via quantum entanglement there.  To be safe you have to disconnect it from any power source.
Answer: Firefox is better than any other browser, Even Chromium is a processing hog for Raspbian. You can use FF if you want.
Answer: Dunno why you would think it might not be safe on the Pi if it is safe on the Mac.  Anyway, it's in the normal repositories -- try:
apt search firefox

I think the thing you want is firefox-esr (but see below).  Anything in the repo can be considered as "reasonably safe":  Obviously any and all software is susceptible to bugs and security issues; Debian, which is the foundation of Raspbian/RpiOS, is very good at identifying and dealing with the latter.
WRT firefox, there's a bit of a weird history within Debian derived distros.
Basically, there is/was a version of firefox called "iceweasel" that was used to circumvent some copyright issues.  It's still in buster as "a transitional package which can be safely removed".  I just mention this because you may see it referred to elsewhere particularly in older information.
Comment: I had read about Iceweasel BUT where I came across the notion that FF was an issue I cannot remember! And yes, I know nothing is 100% safe

Firefox for Raspi


Why did Arya just walk away instead of killing this character?

Question: In the book and the show things don't go too well for the Hound. In both cases, he gets horribly wounded and asks Ayra to kill him. However, she does not. Why is this? What message was she trying to send? All that Sandor is greeted with is silence. I thought it was a tad bit odd since originally the Hound was on her list of people to kill.
Comment: You may want to look at this: http://movies.stackexchange.com/questions/21300/why-did-arya-refuse-to-end-it
Answer: The message Arya was trying to send is that the Hound doesn't deserve a clean, merciful death.
In my opinion, this action foreshadows Arya's future path in Braavos:

 She is trained in the House of Black & White, the temple of the Faceless Men. The Faceless Men call mercy kills "the Gift". Without her knowing yet, Arya is denying the Hound this "gift".
Comment: @TLP That's definitely not the vibe I got from the TV series, and not the vibe I remember from the books either. She doesn't say "sorry, I cannot do it". She doesn't look troubled at the prospect of killing her friend. Arya looks at Sandor with cold disgust. To me, it's clear she's thinking he doesn't deserve mercy.
Comment: Or she just could not bring herself to do it, because they had become friends.
Comment: In the books, it is clear that she it conflicted. One time she leaves his name off her list, thinks about it for a while, then adds it back in. I believe she says something like "You should have saved my mother" and then leaves, which I interpreted as her not wanting to admit to the weakness of not being able to kill him. The TV-show is showing Arya as very cool and callous, borrowing from the *Mercy* excerpt from *The Winds of Winter*, so its possible they went for that version instead.
Answer: In Chapter 74 of A Storm of Swords Arya tells him

"You don't deserve the gift of mercy."

There may be more to it, but reasons she gives at the time are

 She never forgave him for killing Mycah, or for hitting her with an axe instead of trying to save her mother at the Red Wedding.
Comment: The latter point is very dumb from her perspective. How could the hound have saved Robb and co versus  dozens of soldiers?
Answer: I have only watched the show, but to me it is clear that she is conflicted in many ways about killing the hound at this point.
Firstly, she wants him to suffer, he killed the butcher's boy as well as the farmer (who he nicked the silver coins from) and therefore she hates him. However, he has also been her protector to a degree and she likely knows that she owes him her life to some degree while at the same time being his captive. Lastly, I think she is still a young girl and while she has killed a few folks here and there, she has never killed someone who she has a relationship with.
In the end, I think she chose the easiest way out for herself, letting him die in the wilderness by lack of action on her behalf.
Comment: @PaulD.Waite Looking at it again, they walk off from the farmer, leaving him flat on his back head bloodied and he doesn't get up as they leave (or so much as move too much). I assumed that he was on his last breaths.
Comment: "he killed the butchers boy as well as the farmer (who he nicked the silver coins from)" — I don't think the farmer died in the TV show at least.
Comment: sure, he certainly could be on the way out. It's just not super-strongly implied that he would die directly of the wound he gets from the Hound. I think the Hound says "He won't survive the winter" to justify taking his silver, implying the Hound at least thinks the farmer is going to die in the future, but from other causes. He doesn't say "Eh, he would have died anyway even if I didn't just kill him."
Comment: He didn't kill the farmer, nor did he ever intend to. He simply beat him until the farmer gave up the silver. Regardless, there are other more pointed reasons why she would harbor resentment for the Hound. Such as the fact that he hit her with an axe and fled the Red Wedding instead of trying to save her mother and brother.
Answer:
"It's pretty firmly established that she did have him on her list." –  Monty129 Jul 9 at 0:14

I agree it was clearly established that the Hound was part of Arya's list, which is why NOT killing him was the only way to convey with certainty that she had removed him from it. Whether she feels he doesn't deserve her mercy or whether she simply can't bring herself to kill someone to whom she has grown close is far less evident. I personally believe she posses the strength of character to deliver mercy, therefore I suspect that, while she has developed an affinity for the Hound, she still harbors resentment about his past cruelty and is unwilling to intervene.
Comment: I don't remember her ever developing any warmth toward the Hound. He was simply a means to an end. And when his end came, she doomed the Hound in the same way he doomed the farmer; she stole his silver and left him to his inevitable fate. Poetic justice.
Answer: Arya developed a conflicted relationship with Sandor. He taught her how to survive on her own. He gave her the common sense and necessary evils she needed to stay alive but she still had a heart. As did the Hound. I think she left him, took his silver, etc to make a point.
When they left the farmer, they were arguing... the Hound was convinced that he would die.

Sandor: Aye, he's a good man. His daughter makes a nice stew. But he's weak. They'll be dead come winter.
  Arya: You don't know that.

By leaving him, she KNEW he wouldn't die. But by taking his silver, she sent a poignant message.
That just because he is gravely wounded and "weak"... he won't necessarily die. Which is why the Hound broke his own "code" and took the farmers silver. Arya knows that Sandor has good in him. And that's the reason he "will never be a real killer".
Comment: Welcome to SFF! This is a nicely reasoned answer, make sure to register your account and take the [tour]!
Answer: When his silver was about to be taken by Arya, he tried to take it back. He had said in a previous episode that "dead men don't need silver". When Arya saw this, she knew that the Hound still has hope that he will still live. She decided to just leave him there without taking away that hope.
This is just what I think. I've only seen the TV show and I don't think TV show Arya can resist caring for the Hound even just for a little bit.
Answer: I think it's both. On the surface (and what she shows to him in her behavior and words), Arya is leaving The Hound to suffer and bleed prefusely, and die on her terms - devoid of mercy, similiar to how he treated his victims. A part of her despises him, his previous malicious actions and what he stands for. He killed her friend, served the Lannisters, failed to save Catelyn and Robb at the Red Wedding, he had her captive and up for sale - and he is an early name on her "To Kill List".
On the other hand, deep inside she has developed feelings of friendship and gratitude towards him as well, knowing he saved Sansa from rape, he despises Joffrey and the Lannisters, he basically saved her from her mother and brother's fate at the Red Wedding, he was her companion and some kind of a guide to her (teaching her mostly violence, naturally for Game of Thrones), and in a way she now owes him a debt which is problematic because he's on her list.
In my opinion, it's not that she couldn't do it morally... It's that she didn't want to. And she was convinced he was dying in agonizing pain anyway. Watch Season 6 knowing all this...
Answer: I definitely feel like she didn't kill him because they grew close. He's one of the first people to be on her list, and she has plenty of opportunities to kill him. Everyone else she comes across who happens to be on her list meets their demise. But she won't kill The Hound because he's not on her list anymore. Although, she doesn't feel like she needs to help him either.
Comment: The Hound is hard to kill. Brianne had to "van Gogh" him before she managed to subdue him, and even that was by chance. In the books he dies from an infected wound, and not in battle too. Each time he told Arya that she has one shot, but if she fails he will break her arms, or whatever. That's a chance one has to consider.
Answer: By not killing him Arya is conveying that she has forgiven him for his past crimes. Killing him would have crossed him off her list and thus the 'forgiveness' would have been hard to show. Yes she could have said it with words but that would have been 'weak' and the Hound would have felt shame by doing it.
Answer: In the TV show, she takes his silver. I think this parallels what the Hound did with the farmer, the Hound said "Dead men don't need silver". Someone mentioned above the farmer was still alive. I don't remember that, but it would make sense if these scenes were meant to be related.
Answer: Not true. Don't tell lies. Why even make that up. She left I'm coz she felt a sense of duty as he had looked after her all that time. Even tho he's on her list she relished he wasn't so bad. So instead of killing him she left him also didn't help and left it up to gods to decide. He was the only person that looked after her in years. To be fair he was a dad to her. Yes m watching for 3rd the and see diff things. Pure love hound now lol
Comment: Hi, welcome to SF&F.  I'm not sure what you're addressing here.  Who's lying?  Please answer the _question_, don't respond to other answers.  If you have an answer to the question that _isn't_ covered in the existing **10** answers, please rewrite this to focus on the question and why Arya didn't kill the Hound.


Connecting 14 AWG to 12 AWG for oven operation

Question: I have a new wall oven to install.  Both old and new oven are 30Amp units.  Old wiring from local oven junction box is 14 AWG (pig tail - 6ft).  New oven is 12 AWG, 3ft pig tail (will not reach junction box and is hardwired into new oven controls).  I want to put a 30 Amp plug/receptacle in the oven space to connect the two pig tails.  Can I connect both 14 gauge and 12 gauge wires through the receptacle (14g) and a plug (12g - new oven)?  The 12 AWG oven ground will be connected to the 14 AWG ground old oven wire directly. Ok?
Comment: A 30 amp circuit should use at least 10 AWG, a 40 amp circuit at least 8 AWG.
Comment: Seriously under-wired... 14ga fusible links is one way to think of it.
Comment: Where did you even get a new 30 amp oven with 12GA wire??
Answer: A 30A connection will require a much heavier wiring connection than either 12 AWG or 14 AWG. It is common that a 40A or 50A cord is used to hook up a range unit. These can be purchased in several lengths with molded on plugs at the end.
As always make sure that your outlet, wiring back to the entrance panel and the circuit breakers are sized properly for the load. The circuit components are normally rated a bit higher than the maximum current draw of the range. So a range unit that pulls 30 or 32A should be on a 40A circuit.
Comment: Note that the large-gauge wire (10 or 8 GA) must go all the way back to the panel. If the current junction box has 14GA wire coming out of it, it's possible it's 14GA in the wall as well. I would say the whole circuit needs to be looked at.


Pre-sale wallet and DAO hard fork

Question: Assuming, I've never imported my pre-sale wallet from the initial ethereum crowd fund, could I simultaneously send the the contents of my wallet to an ETH address and an ETC address? I'd like to sell the ETC from the wallet but don't want to risk losing ETH.
Answer: As long as you send your ETH to an ETH address which you have the private keys to, you are not losing your ETC. ETH addresses are also valid ETC addresses!
After importing your ETH from the presale wallet, it will (should?) also import your ETC from the presale wallet in the very same transaction on the Etherem Classic chain. You should have both your ETH and ETC on the same address. You can carefully check this by running two geth or parity instances on each chain, e.g.:
parity --chain homestead --port 30303 --db-path ~/.parity         # ETH
parity --chain classic --port 30304 --db-path ~/.parity-classic   # ETC

Or:
geth --support-dao-fork --port 30303 --datadir ~/.ethereum        # ETH
geth --oppose-dao-fork --port 30304 --datadir ~/.ethereum-classic # ETC

After importing and holding both your ETC and ETH on your local account, continue with splitting them carefully by following this excellent guide.

Pre-sale wallet and DAO hard fork


Can cooking oil kill fleas?

Question: I cannot find a reliable way to kill fleas after removing them from my cats with a flea comb.  Soap and water does not do the job and they climb back out of the drain.
Will cooking oil  suffocate fleas?  If so how long of time until the flea expires?
Comment: You can easily drown them in a glass of plain water; they stop moving within 10-20 seconds, but you could leave them longer to make sure. Just don't look closely at them during this, as some may find it upsetting.
Answer: Short answer: Mire them in a viscous liquid then leave them in there long enough for them to die, instead of immediate disposal.
Cooking oil is viscous, so yes you can viably use it to mire the fleas. You'll need to wait until they die though to dispose of them or else they'll come crawling back as you've stated. The DIY option is generally a water/dish soap mixture in a container: you'll put the fleas in and they sink to the bottom almost immediately. Just leave them in there and they'll eventually die in about 5 minutes. Some individuals suggest Dawn dish soap, much like here, where the claim is that the Dawn contains compounds which suffocate the fleas.
You can also make a flea trap for around the house, with a bowl of dish soap and water near a night light. They'll jump for the light and end up falling into the flea trap.

Can cooking oil kill fleas?


Where can I find the Arduino Mega core code?

Question: I am looking to modify the receiving hardware serial buffer size for the Arduino Mega. To do so I need to redefine it in HardwareSerial.h in the core code. However, I can't seem to find a copy of the Arduino Mega core code. A search for HardwareSerial.h on my computer returns no results. I am using Windows 10.
Comment: And how / where on your computer did you search? Did you look inside the Arduino software itself?
Comment: Here https://github.com/arduino/Arduino/blob/master/hardware/arduino/avr/cores/arduino/HardwareSerial.h
Answer: Arduino Mega is part of the Arduino AVR Boards core. The location of that core depends on whether you are using the core version included with the Arduino IDE or have updated the core version using Boards Manager(in which case there will be multiple copies of the core installed on your computer but only the updated version will be used). The easiest way to find it is:

Tools > Board > Arduino/Genuino Mega or Mega 2560
File > Examples > EEPROM > eeprom_clear
Sketch > Show Sketch Folder
Move up folder levels until you reach the avr folder.
If there is a version number folder in the avr folder then open that folder.
HardwareSerial.h and the rest of the core files are located in cores/arduino.

Remember that you will need to redo any changes to the core after any Arduino IDE and/or Arduino AVR Boards updates.


Is a .vdi file for VirtualBox Cross-Platform?

Question: I have a .vdi file on a Windows 64 bit.
Can I use the same .vdi file on a different machine like a Linux 32-bit, without problem?
Answer: The short answer is yes - the file itself contains nothing in it that is specific to the host operating system. You will need to make sure you bring along the virtual machine definition file (it is XML) usually ending in .vbox for recent versions of VirtualBox.
That being said, despite the virtual hard drive being fine, your guest virtual machine may not work on 32-bit linux of you had configured the guest as a 64-bit operating system. There may be other weird hardware differences too, though the best thing to do is to just make a backup and try it. It may adjust to the new hardware and just need a simple reboot.


is there a shortcut to expand folders in Finder while being in Cover Flow mode?

Question: in Finder I can use the arrow keys to go up and down and with "left arrow" and "right arrow" I can expand a folder while being in List View mode.
However, when I'm in Cover Flow mode the "left arrow" and "right arrow" do the same as "up arrow" and "down arrow", i.e. just go up and down in the list.
How can I expand a folder while being in Cover Flow?
Answer: aaaand while typing the question I just played around and figured it out:
In order to expand a folder you need to use COMMAND+"left arrow" and COMMAND+"right arrow" respectively.


Diophantine equation-positive solutions

Question: Consider the equation $(x+1)(y+1)(z+1)=3xyz$. I want to find all positive integer solutions such that $x\le y\le z$ to this equation using only pen and paper and mathematical techniques. How can I do this rigorously(ie also showing that the solutions you come up with are the only solutions)? An at least semiformal solution would be appreciated.
Answer: Dividing by $xyz$, we are led to
$$\tag1\left(1+\frac1x\right)\left(1+\frac1y\right)\left(1+\frac1z\right)=3,$$
hence (assuming $0<x\le y\le z$), we need that the biggest factor $1+\frac1x$ is at least $\sqrt[3]3$, i.e. $x\le 2$.
Case (i): $x=1$.
Then the equation $(1)$ becomes
$$\tag2\left(1+\frac1y\right)\left(1+\frac1z\right)=\frac32$$
and we conclude $1+\frac1y\ge\sqrt{\frac32}$, i.e. $y\le4$.
Thus the allowed cases $y=3$ and $y=4$ can be easily checked by hand: $y=3$ leads to $1+\frac1z = \frac98$, i.e. $z=8$, whereas $y=4$ leads to $1+\frac1z = \frac{6}{5}$, i.e. $z=5$.
Case (ii): $x=2$.
Then the equation $(1)$ becomes
$$\left(1+\frac1y\right)\left(1+\frac1z\right)=2$$
and we conclude $1+\frac1y\ge\sqrt{2}$, i.e. $y\le2$ and together with $y\ge x$ this means $y=2$ and finally $1+\frac1z=\frac43$, i.e. $z=3$.
In summary, the only solutions $(x,y,z)\in \mathbb N$ with $x\le y\le z$ are $(1,3,8)$, $(1,4,5)$, and $(2,2,3)$.
Answer: The LHS has $xyz$ as its highest power term and the RHS has $3xyz$ so if we consider large $x$ the RHS should dominate the LHS. That would let us eliminate large values of $x$ and only have to deal with small $x$.
To do this we need to find some lower bound on $x$ that $$(x+1)(y+1)(z+1)-xyz = (xy + xz + yz) + (x + y + z) + 1$$ cannot beat $2xyz$. Because $x \le y \le z$ we can bound $$(xy + xz + yz) + (x + y + z) + 1 \le 2xz + yz + 2x + z + 1$$ whereas $$2xyz > 2yz + yz + yz + 2yz + 2yz \ge 2xz + yz + 2x + z + 1$$ as long as $x > 4$ (compare term by term using $x \le y \le z$ to see the last inequality). This shows the Diophantine equation cannot hold for any $x > 4$ (and in fact you could make this bound tighter then you'd have less cases to do).
Now we only have to characterize the solutions to any of:

$2(y+1)(z+1) = 3yz$
$3(y+1)(z+1) = 6yz$
$4(y+1)(z+1) = 9yz$
$5(y+1)(z+1) = 12yz$

these are all easy to do I'll show how to do $5(y+1)(z+1) = 12yz$: it's just finding positive integer solutions of $$y = \frac{5z + 5}{7z - 5}$$ and that demands $5z+5 \ge 7z-5$ which only happens when $z \le 5$ so just check each one and we get solutions $(4,5,1)$ but obviously discard that since it's not in order (they will all come up in the correct order).

Diophantine equation-positive solutions


Can I put a smaller size tire on staggered rear rims which will allow me to use the same size tire on all four staggered rims?

Question: I drive a 2015 Mercedes S63 AMG 4matic.  The rear wheels are staggered with 285-35-20 tires on 20/9.5 wheels, while the front tires are 255-40-20 on 20/8.5 wheel.  The current rear tire size only comes in a summer tire and I need all season tires on the car.  Therefore, I want to buy 4 all season tires sized like the front wheels.
Comment: Welcome to Motor Vehicle Maintenance & Repair! If I were you, I'd get a second set of rims for "all season" driving, and keep the other set for summer driving. Your second set could then be the same instead of staggered, which would allow for all four tires to be the same. Just my thinking.
Answer: The problem you have is that your rear wheels are wider than your front wheels, so your rear rims are wider than your front rims. You can't put a narrower width tire on a rim than it is designed for as it won't make contact with the rim.
You could get narrower rims for your car, I wouldn't recommend it because you have a powerful rear wheel drive car and the extra width gives more grip so your rear end is less likely to break free. If you put narrower rims on you increase the likelihood you'll end up wrapped around a tree.
I did a quick search on a couple of tire sites for your tire sizes and found at least 20 choices for summer, winter and all season categories from many different brands and price ranges, so it seems like you probably have some choice. It's not important to have the same tire brand or model on front and rear, you just need tires that match up reasonably well in type and rating so they give similar grip, so don't change your rims just so you can have the brand or model of tire.
Answer: As your car is 4 wheel drive, it's important to keep to outside diameter the same to avoid abnornal load and wear on the centre diff/transmission. The width is not as important.
This site shows a 0.6% difference in OD with your current tyres.
As Paulster suggested you could buy a 2nd set of rims specifically for winter tyres. And there shouldnt be any risk going to the same width front & rear. Winter/snow tyres are typically higher profile and narrower than standard.
I'd reccomend to talk to a Mercedes dealer for reccomendations and then look for competitive alternatives. It's important to get the correct size, stud pattern and offset for your car.
One advantage of having winter rims is that it saves your nice factory rims from being eaten by salt & grit. Also being able to swap and store them means you'll get better useful life out of the tyres.
Note: Some countries require tyres to match left/right & front/rear. Check the legal requirements for where you live.


D750 error when photo not taken at widest aperture

Question: I recently purchased a Nikon D750, and I have two lenses one of them being a second hand 70-200 f2.8 VR, and the other being a 50mm 1.8g. Today I noticed every time I take a photo that is not at the widest aperture e.g. 1.8 or 2.8 it comes up with the Err message on the LCD screen meaning "Camera malfunction" and then will not let me change the settings (aperture + shutterspeed) unless I restart the camera. Do you know if this is a common occurence or is it just a faulty camera?
Comment: Different Nikon model, but the same exact issue.
Answer: The likely issue is a fault in the aperture control mechanism, either of the lens or camera.  There is a mechanical linkage there, where a small lever in the camera pushes a flat metal lever on the lens to adjust aperture.  If you have tried multiple lenses the likely culprit is the camera. If you want to check, set a long exposure (so you can see better), on manual, set the aperture to small (say F16 or so) and expose, then look down the lens, and see if the aperture blades close.  If they do not, take the lens off and move the lever in the lens by hand (it is the reverse there, where you move it to open due to spring loading).  If it moves smoothly on the lens, the camera needs repair. The camera's control mechanism does not need to move when the aperture is wide open, which is likely why the error only occurs when stopped down.
If the control mechanism is failing to close the iris, it is likely in the mechanism itself (a hugely complex looking mass of gears). If the mechanism is failing to open the iris (i.e. on mounting the lens the blades remain closed as you twist the lens in) sometimes it can be because the lever in the camera is bent out of the way and not contacting the lens lever, and can be bent back.  That does not appear to be your problem, and so I think only a repair shop can correct it by replacing the control module.


Why didn't my answer get more upvotes?

Question: As a newcomer to this site I'm trying to understand how it works. I answered the question Who was the first retailer in Monterey, California? and whilst I wouldn't expect my original answer to get many upvotes as it didn't answer the question I believe the additional information I provided in a modification was pretty comprehensive, properly sourced, and based on original research including this particular item Vallejo document which I would challenge anyone to find as there are 78 volumes of Vallejo documents, each containing several hundred pages, with no index. I also answered the question and again would challenge anyone to suggest that my answer is in any way incorrect.
The previous answer to the question received 3 upvotes to my 2 and yet it didn't provide the correct answer to the question. So why hasn't my answer received more upvotes? What's wrong with it?
Comment: I didn't read your answer simply because I didn't read the question.  The topic is one on which I have little knowledge, and the questions about Monterey tend to be obscure and punctilious.  Having read it, I upvoted as well researched and the kind of answer I want.
Comment: I can't speak for anyone else, but I don't like to upvote things I haven't fully read, and that was just too much text for me to slog through.
Comment: Ok then, but to focus on one specific - the other (brief) answer states "Thomas Larkin opened his store in 1834". Where is the source for the evidence of that statement? My answer is as concise as it can be to provide the sources and evidence for the conclusion. Please tell me which part of the answer is superfluous. If you prefer answers to be brief but unsupported then make that clear.
Comment: To be able to answer that question in the comment, I'd have to not only read through it all, but then analyze it as well. If I'm not particularly interested in donating the time to do the former, you certainly can't expect me to do and the latter as well.
Answer: The number of votes received is very seldom related to the quality of the answer, but more so to the popularity of the questions subject. The question you answered is several years old, and has an existing, accepted answer, and as Mark points out is too specific to be of general interest for many of our users.  Adding the length of your answer to the lack of general interest in such a specific topic, and votes may suffer accordingly.
(I don't think any one of us has not had the situation where we put a lot of effort into what we felt was a 'great answer', only to get little acknowledgement in the form of votes)
On answer length, the only advice I would give is make the answer as long as necessary, but no longer.  If your answer is long, make sure we can find your conclusions clearly stated (perhaps summarized) so we can decide if we wish to read the entire body of the answer. (The TLDR is a thing here.)  Personally on long answers with large quote blocks I like to see a little emphasis placed using bold to draw my attention to the relevant bits.
If you intend on participating further, I think you will receive a positive response from the community.
Comment: This is very true, in that the correlation to question upvotes is much stronger. I think my current record here for upvotes is on an answer for a question that has 83 upvotes and views in the 10's of thousands. That answer didn't *suck*, but I doubt anyone here would call it my best work. Getting 3 upvotes on an answer to a question that got 3 upvotes really isn't bad.

Why didn't my answer get more upvotes?


How to update the CMS component of a particular field using SDL Tridion

Question: How can we edit one particular field of existing CMS component using Core Service API. We can parse through XML elements and update one particular field. But then this update method has to be written for each schema component I have to update. Is there an update method in API that updates one particular field leaving rest untouched?
Comment: Hi Ritesh. Welcome to Tridion stack exchange. I'm sure there will be plenty of help available, but first of all, you'll need to work on making your question clear. Frankly - I have very little idea what you are asking. Are you wanting to update a component in the content manager? What is a COEW? What exactly have you tried already to solve your problem? Perhaps you could post your code and explain what you expect it to do, and what it does that doesn't meet your expectations. If you can clear some of these things up, you will probably get very effective help here.
Comment: Would you mind sharing the code that you wrote, which has this issue? That's really the easiest way to troubleshoot code that doesn't work as you intended.
Comment: I fixed a few obvious typos, hope they were indeed obvious, but please review and edit your question to make the language clear. It is fine if English is not your native language, but just spending a few seconds to review what it says before you post will be helpful to everybody.
Answer: I agree with the comments that your question is rather vague and could use some improvement, please edit your question and add some updated info in case my answer isn't relevant.
But in the mean time, I can answer what I think your question might be. You seem to want to change a value in a Component based on other values in the Component. You mention you need to do that when something changes in the Component.
This sounds like you are in need of event handling, rather than to update the Component via the Core Service. Please take a look at the following topic in the online documentation, it describes how you can add event handlers which you can use on a Component save action. Then your code will be triggered at the right time and you can check the value of the field and update accordingly.
A long time ago I've written an example event system which contains quite a few pointers about reading and editing Component content. Please take a look at the
Rapid Editorial Interface eXtension (source code included).
Answer: You can create a function like below for example, so that you don't need write it for each component type.
<code>public void UpdateField(string componentID, string fieldName, string fieldValue, bool isMetaDataField)
        {
            try
            {
                ComponentData firstComponent = (ComponentData)tridionClient.Read(componentID, null);
                XDocument doc;
                XElement xmlData;
                if (isMetaDataField)
                {
                    doc = XDocument.Parse(firstComponent.Metadata);
                    xmlData = doc.Root;
                    XNamespace ns = xmlData.GetDefaultNamespace();
                    if (xmlData.Descendants(ns + fieldName).Count() > 0)
                    {
                        xmlData.Descendants(ns + fieldName).SingleOrDefault().Value = fieldValue;
                        firstComponent.Metadata = doc.ToString();
                    }
                }
                else
                {
                    doc = XDocument.Parse(firstComponent.Content);
                    xmlData = doc.Root;
                    XNamespace ns = xmlData.GetDefaultNamespace();
                    if (xmlData.Descendants(ns + fieldName).Count() > 0)
                    {
                        xmlData.Descendants(ns + fieldName).SingleOrDefault().Value = fieldValue;
                        firstComponent.Content = doc.ToString();
                    }
                }

                try
                {
                    tridionClient.UndoCheckOut(componentID, false, null);
                }
                catch (Exception ex)
                {
                    // fail silently
                }
                tridionClient.Update(firstComponent, new ReadOptions());
            }
            catch (Exception ex)
            {

                throw new Exception(string.Format("[UpdateField] :: Error: '{0}'", ex.Message));
            }

        }
</code>
*** You may need to adjust the code, the way it's saving the component. but it works perfectly.


Baking below sea level

Question: I now live on the Sea of Galilee (600+ feet below sea level), and my cakes all seem to fall, no matter what I do. Is baking affected by being below level?
Comment: I have heard of decreasing the amount of raising agents at higher altitudes to account for the lower atmospheric pressure, so it follows you may need to do the reverse for higher pressure areas.
Comment: Have multiple recipes failed in the same way or are you having a problem with one specific recipe failing over multiple tries?  Can you summarize your recipe including all ingredients and an outline of the directions?  And while @ElendilTheTall's observation is probably the most pertinent, it is also worth asking how fresh your leavening is - chemical leavenings like baking soda and baking powder lose their effectiveness in storage after they have been opened.
Comment: You're 600 feet below the sea? I'd have thought all the water down there is putting out your stove?
Comment: Jokes aside, could you give an example of what you've tried baking. Especially regarding the rising agent used (yeast, bi carbonate soda etc). As far as I know really cakes should be rising more, not less at level levels. It's when you get high the issues usually arise (no pun intended) partly due to the changing boiling levels (69c for boiling water on mt Everest for example)
Comment: Welcome to Seasoned Advice, and thanks for posting your question! This is a pretty unique problem (not a lot of people live below sea level!) so if you have trouble getting confident answers here, you might also just try asking others who live there. If you do figure anything out that way, we'd really appreciate if you come back and post your findings as an answer. (Don't worry, we encourage answering your own questions.)
Answer: Your altitude won't matter in your baking. Whatever reason your cakes have for not rising, it's not that you are a tiny bit below sea level.
First of all, some personal observations on altitude: I've baked frequently at about 750 meters (let's round it to 2500 feet) and also in my current home at about 130 meters (about 425 feet). The same recipes work without noticeable differences in rising. A reduction of over 2000 feet doesn't bring much visible difference, much less the difference between "working perfectly" and "falling". Even if your recipes were perfected for 0 feet (which they aren't, cooks don't do it that precisely), a reduction of only 600 feet will be unnoticeable.
Second, what could the theoretical effect on rising be? Well, the air has less pressure due to altitude, so you'd expect slightly higher density; the thousands of air bubbles in the cake won't expand as much. How much is this "slightly"? Don't forget, air density depends on both pressure and temperature. For comparison, I calculated the air density at different heights and temperatures: It is the same density if your air is at 600 ft below sea level, heated to 175 Celsius (a common cake baking temperature), or sea level at 165 Celsius.
Now, our ovens have nice knobs graded in small intervals, but they are actually very bad at keeping temperature. It's not only that their mean temperature is badly adjusted (I've frequently seen ovens running 40 Celsius low), but also that their temperature fluctuates all the time with an amplitude much higher than these paltry 10 Celsius. And this is only the temperature outside of the cake; the air inside the cake (which does the expanding) never reaches 175 Celsius. A cake is ready at 100 Celsius internal temperature at the latest (all starches have gelated by then), frequently below that.
So, to summarize: A cake's height will change a lot more during a bake due to random factors than due to your altitude. Even if you had a perfectly controlled process, you'd need vernier calipers to measure the difference in height. But when using an only reasonably controlled process at home (ingredients at room temperature, measuring weight with a digital scale, controlling oven temperature with a thermometer), you will already see fluctuations larger than the effect of 600 ft altitude difference.
Appendix
My calculation (formula and gas constant from Wikipedia, air pressure at different heights from engineeringtoolbox):
Answer: Hello lorraine and welcome to Seasoned Advice! Baking below sea level can require adjustments just as baking at high altitudes can. AS @ElendilTheTall notes, you would need to do the reverse.
Please see this from the Essentials of Food Science  textbook , page 374. (The link is to a .pdf version.)

Altitude-Adjusted Baking
As a reference, water boils at a lower temperature with higher elevation: a few
  C or approximately 10F less, 203F 95C at 5000 feet, and 198F (92 C)
  at 7500 feet. Therefore, foods cooked in water have to be cooked substantially
  longer to get them done. Even when water comes to a rapid boil, it is not as hot
  at high altitudes as rapidly boiling at sea level!. Baking requires an increase in
  time too. At lower altitudes water boils at a higher temperature and an increase
  in leaven is needed.
When a product is baked at high altitude, there is less atmospheric resistance
  and it takes longer to bake. The lowered air pressure also tends to cause the
  air bubbles in baked goods to rise faster, producing increased dough expansion.
  Then these air bubbles escape to the atmosphere causing the cake to fall. The
  inverse is true regarding low altitudes and high atmospheric pressure. Therefore,
  local instructions specific to the altitude must be followed in manufacturing, food
  service, or home recipes.

The page goes into much more information including adjusting the amount of sugar, leavening, and liquid. Just keep in mind that it's always the reverse for low altitude as it is for high.
Comment: Boiling point of water at 750 feet below sea level is 100.8°C (213.5°F). http://www.engineeringtoolbox.com/boiling-points-water-altitude-d_1344.html That small a change from standard is not likely to cause baking problems.
Comment: I'm not sure that 600 feet below sea level will be enough for this to matter that much though. Some experimentation is needed.
Comment: Admittedly the differences may be small, but in baking even minimal differences can cause issues. Re experimenting, have at it! :)

Baking below sea level


Academic pipeline: How many papers should you have under review?

Question: Often I've come across rules of thumb about maintaining active publication record. The advice I've most often been given is that one should have at least two papers under review at all times? What's your strategy? I am in the social sciences.
Comment: For what purpose though ? are you a grad student trying to graduate ? postdoc trying to get a job ? tenure-track faculty trying to get tenure ? In the absence of other information, the only real answer is: as many as you have interesting ideas out there worth publishing
Comment: That would very strongly depend on the duration of the review process. At our department the "target" is 1.1 peer-reviewed publication/scientist/year.
Comment: I agree that "as much as possible" is oppressive. Looking at community norms is helpful here.
Comment: gerrit: in my discipline, the usual review takes about four to six months. Suresh: i am a grad student trying to build a cv that screams: i can do the job. i am about half way through my program, three publications under my belt. i am looking for a way to set up a rhythm. i find that the strategy "as many as humanly possible" is much too oppressive. sure, i can work around the clock and never be satisfied, but it seems more realistic to set up targets.
Comment: Maybe the real question is another one: when I am given a new paper to review, for which value of $N$ will the editor accept as an answer "sorry, I am too busy, I already have $N$ reviews to do now"?
Answer: You're simply asking the wrong question.  Your goal should be to do the best work you can, not the most — quality, not quantity.  One revolutionary paper is worth far more than dozens of incremental papers that nobody reads.
To put it another way, if you find yourself submitting so many papers that you're worried about being overwhelmed, you're doing something wrong.  Aim higher.  Publish fewer, bigger chunks of work.  Spend less time writing and more time thinking and digging.  Stop just writing papers and develop a research program.  The CV bullets will take care of themselves.
Answer: Saying you should always have N papers under review is foolish. Say N = 2. You've just submitted a paper, and then a few days later, the other paper comes back from review with an acceptance notice well ahead of schedule (in two months instead of four). Does that mean you have to submit another one immediately, in order to have two in the pipeline? That doesn't make sense to me, as it makes your work subject to arbitrary deadlines that are orthogonal to producing high-quality publications.
You should keep a general track of how the work in your group (or your own work, if you report to someone else). You should also keep track of the general expectations of someone at your current career stage, and make sure that your publication output is consistent with your peers. (Don't worry about exact agreement: producing 80 or 90% of the total output is not really a big deal; producing 25 to 50% is likely to be an issue.)
Beyond that, however, you should focus on making sure your publications have quality, with a much lesser emphasis on quantity. One Nature or Physical Review Letters (or equivalent journal in your chosen field) article is probably worth a lot more than two or three publications in other journals.
Comment: +1 for "look at your peer group to determine competitiveness"
Answer: JeffE's answer is excellent, and probably the most "correct". Nevertheless, as food for thought I offer the following anecdote from Bayles and Orland's Art and Fear:

The ceramics teacher announced on opening day that he was dividing the class into two groups. All those on the left side of the studio, he said, would be graded solely on the quantity of work they produced, all those on the right solely on its quality. His procedure was simple: on the final day of class he would bring in his bathroom scales and weigh the work of the "quantity" group: fifty pound of pots rated an "A", forty pounds a "B", and so on. Those being graded on "quality", however, needed to produce only one pot - albeit a perfect one - to get an "A".
Well, came grading time and a curious fact emerged: the works of highest quality were all produced by the group being graded for quantity. It seems that while the "quantity" group was busily churning out piles of work - and learning from their mistakes - the "quality" group had sat theorizing about perfection, and in the end had little more to show for their efforts than grandiose theories and a pile of dead clay.
Answer: I somewhat agrees with JeffE, but on the other hand it's not like one can just decide to write a ground breaking paper.
Having a steady stream of visible work is something positive to get a job, and one should neither publish dozen of small papers nor stall on a very important problem he cannot solve.
One way to get a good balance is to aim for a given stream of papers : if you get them easily, then try harder problem, if you don't, then maybe you should try something more manageable. Of course, what you aim at is very dependent of your field (and even sub-field).
I am in fundamental mathematics and personally like to have, at any given time, at least one paper under review, one paper that mostly needs writing, one idea to develop that could make a paper. In that way, I can focus each (non-absorbed-by-other-task-than-research-)day on what I feel like: writing, reading to back up the idea, do the needed computations, etc. Moreover, having a submitted paper makes me feel more comfortable trying things that take time but have a good chance to fail.
Comment: _it's not like one can just decide to write a ground breaking paper_ — No, of course not.  But _aiming for_ a groundbreaking result tends to produce lots of less groundbreaking but still interesting and publishable side results.  Hence my comment "The CV bullets will take care of themselves."
Comment: Or as I often tell my students: Pick a good unit vector, and good stuff will happen. Don't worry about the magnitude :)
Answer: The advice I've been given for cognitive neuroscience is to (1) make sure I have at least one publication every year, (2) invest the rest of my time in high quality work.
The reasoning is that a full year's publication gap in your CV looks bad, but on the other hand, what people mostly look at when you apply for jobs is where you published the handful of your best papers. One or two high-impact publications are more likely to impress people than ten low-impact ones, but a publication gap looks bad regardless of where your best work got published. How many papers you should have under review at any given moment to fulfill this goal will depend you your research area and the duration of the review process.
Answer: As many as you possibly can (as long as they are quality submissions).
Comment: As long as this is within reason. At some point these are going to comeback from review and you are going to have to revise them.


What are the differences between the MW3 pistols:P99 and the Five Seven?

Question: Which one has a better recoil? How many bullets does each clip hold? What can you attach to these weapons? Do the differences between these weapons make one better-suited for one situation compared to the other?
Answer: The P99 holds fewer rounds (12 vs 16 for the Five-Seven) but does more damage per shot at close range (49 vs 36), although in practical terms this still means 3 body shots to kill a hostile with full life.  The P99 fires faster.  They both have the same attachments available.  (Silencer, Akimbo, Tac Knife, Extended Mags).  I don't have recoil statistics on them, but I believe they are both comparable.
The semi-auto clip-fed pistols are all pretty similar, so which one you choose is mostly a matter of personal preference.  You might switch between them to gain the experience bonuses at various levels of use, but otherwise there's not really a huge difference.
If you want to compare other weapons in MW3, the chart linked from this question:
Modern Warfare 3: Weapon Damage Charts
is the best data currently available.
Comment: @Jo'nathanTummins, if you've got an answer you like, click the check mark under the number of the left to "accept" it, which shows other people that the question is answered.


How long should i wait to see fat reduction in my body?

Question: I am 26 year old male weighing 72.5 kg and height 169cm, I have started working out(Mostly of weight training and bit of cardio) since a month and have reduced from 74.5kg. There is improvement in muscle definition, reduction is tummy a bit. But I am not satisfied with the results. My diet does not contain much protein though i consume 4 egg whites almost daily. Have I made a good progress or should I include whey protein supplement in my diet or should I wait for a few more months of workout and then consider a protein supplement.? I have worked out before as well, but was never consistent.Now I have been consistent since a month.My goal is to reduce weight and to get a good muscle definition
Comment: I tried to give an answer below, but had to make some conjectures. For a better answer it would be helpful to know what routine you're doing, what your short term goals are and where you want to take working out in the long term.
Answer: Dieting Speed:
You lost about 0.5kg (1lb) per week, which is generally recommended for slower diets. The benefits of dieting slowly are that there's virtually no muscle loss (you really only lose fat) and better carryover of good habits to the time after the diet. Also, it's easier to stay sane and keep going, as you're probably not starving throughout the day.
So seeing how you're not really that much overweight I wouldn't recommend losing weight any faster, as that's when detrimental effects set in. You'd begin to lose muscle along with fat, performance drops, comes to a standstill or at least progresses slower. Also, a faster diet is not as sustainable and won't have that much carryover of good habits for after the diet, as faster diets don't work with good habits normally (think 'starving').
Protein Consumption:
You say you're not eating much protein, which could become a problem. Protein is very important to build and maintain muscle mass. No matter if you want to get better at your workouts or just not get worse while losing more weight, you will need sufficient protein. Opinions on what is 'sufficient' differ greatly and depend on what kind of activity you're doing, so it's a bit hard to say right now. If your were weightlifting, I'd recommend 2g/kg (1g/lb) per day. If you're 'only' doing cardio you might get away with less.
Regarding protein supplements: Seeing how you seem to have problems getting enough protein in, this could be worth a try. Generally, you should be able to get everything you need from whole foods, though. Should you for some reason not be able to meet your protein goals, a supplement can help. Keep in mind that it still has calories, however (~120kcal for 30g whey), which you'd have to compensate by either eating less or working out more.
Comment: Thanks for the advice, I eat one whole egg and 3 egg whites a day which may amount to 20gm of protein in addition to normal food. Since my food habits is mostly vegetarian with less protein rich foods.My doubt is since i do mostly of weight training and if do not add protein supplement to my diet will it affect my muscle growth and any other problems?
Comment: I'd say that's too little protein to support a weightlifting routine and this will probably hold you back. The problem is, with a (mostly) vegetarian diet it's even harder to get all that protein and still keep a caloric deficit for weight loss. You might want to look for low-fat cheese and other dairy products (I hope you eat those), as those have a very high percentage of protein. Other than that, supplementing would probably be a good idea then. Just try to get as much protein as possible from whole foods and supplement only when necessary.


Software to invoice clients

Question: I'm looking for some apps to create your invoices which I want is simple and free (such as up to 10 invoices a month) can be managed and organized the invoices online.
I have a good one in my language but I don't know any of them in English.
Comment: Have you tried google? There are dozens and dozens of options out there. If in a pinch, just use Google Docs.
Comment: Might find some useful answers here (although I still haven't yet): https://graphicdesign.stackexchange.com/questions/27539/offline-billing-software-for-freelancers
Answer: I just send plain text emails for invoices. I've had no need for anything more. Easily organized, searchable, and filtered in the email client.

Billed to: [company and address]
_____________________________________________
INVOICE DATE: [the date]
INVOICE NUMBER: [the #]

SERVICES SUMMARY
_____________________________________________

Date      Project               Total
[date]    [ Project title ]     [ amount ]

_____________________________________________

SubTotal  $xxxxx.00
Tax $0.00
Grand Total $xxxx -- Please pay this amount

_____________________________________________

Checks payable to [my company]
can be mailed to the following address:

[My mailing address]

Secure, online payments can be
made at the following link:
http://paymentlink

TaxID [my tax id]

_____________________________________________

TERMS
_____________________________________________

Payment due upon receipt.
[Any other terms]
_____________________________________________

[Full contact info for my company]

Form vs function. When it comes to invoices I don't care a great deal about form. I'm overly concerned with function. I want it to be clear, concise, and contain any information which may be necessary for payment. I don't really care if my plain text email "looks pretty". I just want to get paid and remove any roadblocks where that is concerned.
If a client specifically requests a PDF (some do)..,  well.. I have InDesign or Illustrator so generating an invoice formatted however I want is an easy task. Then I just attach the PDF to my email invoice.
I think most of the "generate an invoice for me" apps are designed for non-designers. No app will ever generate an invoice to my design preferences. I wouldn't use them any more than I'd use a "design my business card for me" app.
Answer: I urge you to look at FusionInvoice (I'm not affiliated). Self hosted, simple and totally configurable (especially if you can code).
@Metis this has an entirely designable (html/css) templating system, and best of all simply sends automated invoices to customers on retainer every month in pdf form.
Everyone will have different needs when it comes to invoicing, but for me this was the only one of (many!) I tried that hit the sweet-spot of simplicity and functionality whilst retaining the all important ability for me to design my own pretty invoices.
It even has enough functionality for me to use it as my basic book-keeping system, arking invoices as "paid" and highlighting those overdue.
Comment: I checked that demo, played with it . Even though it is interesting, it seems quite limiting to me. Granted it was just the demo, but Larval templates doesn't mean "fully customizable" - to learn a template system *for your invoices*?  I guess if you're already familiar with Larval. But there are also a few standard things I do that would require several extra steps for each invoice. I'm glad you like it, but to me, it doesn't appear any better (or worse) than *any* of its competing similar products. The only real plus I saw was the non-subscription aspect of it.  To each his (or her) own. :)
Comment: @Metis Well I code you see, so for me it wasn't a mega challenge to template it. (And I don't know Laravel so I guess it wasn't mega-required to do it...it was a while ago..I recall it at least feeling like just plain html and css). I can't think what your extra steps are that this can't replicate, but for sure invoicing is a very personal thing. For my part I invoice the same amounts to the same people month on month, so automating the process was a massive bonus, and a lot of stress of my shoulders.
Comment: As I recall from my search this was one of fairly few self-hosted setups, and that was a real deal clincher for me. I have enough SASS in my life!

Software to invoice clients


How long does an enzyme work?

Question: I googled this, and I found only that shelf lives are around 2-3 years, but the enzymes use to work even after 5 years if you store them properly. I'd like to know how long I can use an enzyme in solution? Is it hours, days, months? If it is a lot shorter than the shelf life, then why is that?
Comment: Which enzyme and how are you storing it?
Comment: @inf3rno Most enzymes will have significantly degraded in *days* catalyzing a reaction at 10-30°C
Comment: @inf3rno I don't know of any enzymes that are stable in those conditions for that long.
Comment: @WYSIWYG I'd like to decide whether an inorganic catalyst or an organic one would be better for a task. It should catalyze a reaction for at least 2 years without any maintenance in the 10-30°C range. I think enzymes are not that durable, but I am not entirely sure.
Comment: Okay, thanks! Actually I was thinking about using enzymes in fuel cells. Something similar to this: https://pubs.acs.org/doi/abs/10.1021/jp102616m
Answer: The product manufacturer can define a suitable shelf life at a stated storage condition because they've performed stability studies that confirm the product in question remains suitably potent in that timeframe. Often times an expiration date ends abruptly at 1-3 years because the manufacturer chooses not to test out any longer. So that's to say, if you receive a protein with a shelf-life of 3 years, if stored properly the protein may be suitable long after.
It's a fairly different question, however, if you took and reconstituted the reagent, because chances are that stability wasn't tested in that form. In order to make a claim about the stability of a processed/reconstituted protein you need either a statement from the manufacturer, data from someone who has tested stability on it themselves, or you need to test stability for yourself. The fairly short answer is you can't know, and the answer depends on a lot of variables such as the structure, concentration, diluent and storage temperature. All such variables can cause structural changes to the enzyme, i.e. protein degradation, that will result in a different activity for that product.
Comment: @inf3rno Certainly. People have stored antibodies for IHC for years at -80°C. The problem is you can't make that claim with any professional certainty without data to back it up. It's problematic in GMP-compliant processing and FDA-regulated development because you can't use expired reagents for clinical administration, for example, and the only way you can claim to use something past expiration is to test it yourself.
Comment: Can it be even years with the right enzyme in the right conditions? Actually nowadays enzymes can be even designed so my guess would be that this can be maxed out for any enzyme.

How long does an enzyme work?


iPad 2 after iOS 8.1

Question: I just updated my iPad 2 to iOS 8.1 and some bugs were fixed by this upgrade, but a new one has started.  I have Xfinity Home as an App which allows me to monitor my home security cameras through my WiFi.  It worked fine until I put in iOS 8.1.  Now it tries to boot but just briefly flashes the home page and the goes black.  I've tried deleting and reloading the App several times with same results.  Any ideas out there?
Comment: Have you contacted XFinity, or checked their website to see if this is a known issue? Have you restarted your Wifi router as trouble-shooting step?
Comment: I'll call Xfinity tomorrow.  I have tried rebooting the WiFi router.  It works fine on my iPhone, just not the iPad.  Thanks.
Answer: It is probably a bug that needs to be fixed by the developer of the app.
Try using the knowledge base:
http://customer.comcast.com/help-and-support/?CMP=ILCFooter_HelpFAQ
OR
Try contacting Comcast about the issue:
1-800-XFINITY

iPad 2 after iOS 8.1


User Process Tracking, what is this? Numerous alerts with FastCGI

Question: I have a CentOS VPS on Knownhost.com. I am using it to host one Wordpress site, that currently doesn't have any traffic (not launched yet). I was getting these process tracking emails (7 different procs) constantly after Knownhost installed FastCGI.
The problem is i'm not sure what this means... I could find info on google about how to stop it, but not what it means.
Here is an example of message:
<code>Time:         Thu Apr 21 16:25:31 2011 -0400
Account:      myuser
Resource:     Process Time
Exceeded:     1855 > 1800 (seconds)
Executable:   /usr/bin/php
Command Line: /usr/bin/php
PID:          25627
Killed:       No
</code>
The confusing part is that the site is not launched and there is 0 traffic. I also could not find the processes in WHM/Cpanel.
From Knownhost:

We have added the user "myuser" to
  the /etc/csf/csf.pignore file to
  prevent such fake alerts in future.
Please note that Fcgi method is only
  recommended for advanced
  administrators who understand how to
  tune the performance of mod_fcgid. So
  it is better to switch from fcgi to
  suphp.
Let us know if you need further
  assistance.

Would you guys concur with this? I am a linux noob, but I would like to think I could research enough to tune FastCGI (though honestly, I know nothing about it)
Also if it helps, this is from WHM...
Server load   0.00 (36 CPUs)
  Memory Used   13.50% (106188 of 786432)
Answer: I have the same issue, to me it seems like the fastcgi process is running under the user and it is a process that just runs in the background indefinitely. So either set apache fastcgi config to kill worker after it after it is X old.. Or disable the monitor.


Can headphones be damaged by high audio levels?

Question: I'm aware of the damage that can be caused to a person's ears if exposed to frequent amounts of loud sound, but I was wondering if headphones can be damaged by a similar thing. If audio levels are set too high, is it possible to damage the speakers within a pair of headphones?
Answer: Yes, and especially with inear phones, make sure you put them well into your ears. With overhead headphones it's less a problem.
When you don't put inear phones in your ears, most of the sound (especially bass sounds which use more power) will sound much lower, so turning up the volume is the intuitive thing to do, resulting in too much power getting into the inear phones, blowing up the speaker.
Answer: Yes, it is certainly possible to damage the transducers within a pair of headphones by setting the audio too high.
Were you to attach your headphones to a supply of 240v AC at 50Hz you would be likely to burn out the transducers in a very short space of time.
Under no circumstances at all do I recommend doing this, but that would certainly fall under the banner of 'damaged'. Was that what you had in mind?
Comment: Thank you for this. If you had a standard pair of headphones and connected them to a 3.5mm jack, could you do a similar thing by setting levels too high?
Comment: The jack you connect the headphones to is not relevant. What is relevent is the current flowing through the transducers.


How precise do models need to be for 3D printing?

Question: I'm not talking about making something that's outright disproportionate of course. I've been working in Blender and I've use Absolute grid Snap to snap my vertices to the grid. The problem is that it (didn't seem) to always work perfectly for centimeters, and seemed to work better for meters.
(edit: I've learned what the problem was and it was simply the placement of the vertices in side view, being at  slightly different elevations. I'm going to emphasize that the difference was very slight. It was just enough to show up in the measurements. When I switched from front view to side view I was able to adjust the elevation to the grid and that fixed the problem.)
Comment: @user77232: That's not something you can say unconditionally.
Comment: Why not turn off GridSnap if your primary concern is the *length* of a feature, rather than the *endpoints* of the feature?
Comment: It should be ok.
Answer: It depends on what you're working on. If you're producing mechanical/functional parts (even if that just means having to connect to one another or to some non-printed part), 3 mm (0.3 cm) error is almost surely going to prevent them from working. Even 0.3 mm error might be a problem.
If you're doing standalone prints that don't have to interface with anything else, e.g. art, non-articulated figurines, etc., then it becomes just a question of what's visually acceptable, and that's a matter both of scale and of the detail level you want. For typical tabletop-RPG scale, for example, most of the acutal visual features are going to be smaller than 3 mm, so that much error is not going to work out. It might work for large busts, though.
In any case, I would recommend trying to solve the underlying problem. Either change your grid snap, or work at a larger scale and just scale down the final model.
Answer: Welcome to the SE 3D Printing site.  Your questions are also welcome, as well as your answers to your questions, and the questions of others.
I am not a Blender user.  I use CAD systems because most of what I do I want to have a certain dimensional precision.
If the problem is as simple as "The overall object is designed to be 7.345 centimeters but I want it to be 7.000 centimeters," you can fix that when you print the model.  Use the scaling feature of your slicer to scale by $(7.000/7.345)$ or $95.303\%$.  It will print as the size you want.
The problem may be deeper, though, in that you may be having trouble setting points within the model where you want them.  In that case, the snap-to-grid feature is distorting your model's appearance and geometry, and there is nothing you can do to fix it.
If it can't be fixed by scaling, I would suggest that you should either turn off the snap-to features or set up a grid that matches the granularity you actually want for your design.
Answer: After some trouble shooting I realized what was wrong, and now it seems more like a non issue if anything. There's actually nothing wrong with the grid, and the vertices were snapped to it appropriately in top view. The problem was that that my vertices were not at the same elevation (in side view).  The two seemed very close to being snapped appropriately on the grid in side view which is why it wasn't immediately obvious.


F-curve modifier animation - whole values only

Question: Is there a method to have the graph editor only use whole values between key frames? I've tried linear interpolation as to remove any ease in/out.
For example:
I have key frames at frame 1 and 100 that control a modifiers value (also 1-100). When animated at animation frame 50 one would think it should read 50 in the modifier value, but its 49.637 and frame 51 is value 50.963. I'd like the values to only be whole numbers to remove random effects.
So perhaps something that generates stepping in between frames?
Comment: I don't think this is possible at the moment - you can add an f-curve modifier to 'step' based on a number of frames but not to step the actual curve value. I think the only way to achieve this would be to animate another property (eg, the location of an empty) and then use a driver to take that value and apply a script command to 'round' it to the specific step size. Also note that your assumption about frame 50 is actually not correct - frame 50 is 49 frames from 1 and 50 frames from 100 - so is not actually in the centre. For 50 to be the centre you need to animate between frame *0* and 100
Comment: Sorry, I might not have made it as clear as I was hoping. It's the modifier value and frame number that I'd like to match as whole numbers. Frame 1 = value 1.00, frame 2 = value 2.00, etc. So frame 50 should be value 50.00, but using 2 key frames with it set to linear interpolation doesn't give whole values, ie: frame 50 = 49.637. The only work around at the moment I'm finding is keying each frame manually, which is not something I think is the proper/time efficient method.
Comment: It sounds like the best solution for your situation is to use a Generator modifier on the f-curve. This allows you to specifically set a relationship between `x` (the frame) and `y` (the value).
Answer: In order to have the f-curve follow precice values (eg, to follow exactly to the frame number) you can use f-curve modifiers to generate the values mathematically.
To achieve this, you first need to add a keyframe to your property to create the f-curve and then view the properties in the Graph Editor (N).
In the Modifiers section, click Add Modifier and select Generator.

The Generator allows you to define an equation to assign a value for the f-curve (y) for each frame (x) as a polynomial equation. For a 'straight line' relationship you need a '1st order' polynomial - so set Poly Order to '1'.
For the value to always equal the frame number you need to define it as y = 0 + 1x (ie, `y=x') - so set the first parameter to '0.0' and the second to '1.0'.
By ensuring the parameters are integers the result will be an integer for any integer frame number.
You can use this same technique to generate values for more complicated scenarios - for example, to set only for a particular range of frames (enable 'Restrict Frame Range') or to jump multiple values per frame (eg, y = 0 + 5x would increment the value by '5' for each frame) or to use a higher-level polynomial for non-linear relationships.
Comment: This works!!! :D Thank you!


What is the best way to push transactions with hight rate (>1000 per second)?

Question: In order to test the throughput of a private Ethereum, I need to send multiple transactions as fast as possible. Can web3js ensures fast delivery of transactions? or there is an other more efficient way?
Comment: A block is mined every 15-17 seconds, so you're gonna have to squeeze some 15,000 transactions on every block (and hope pray that all of them "got in"). Doesn't sound like something you should be counting on.
Comment: yes, how to ensure that one block will squeeze all the 15k transactions?
Answer: The web3js is just a "gateway" or a framework to make it easier to interact with a node. It doesn't have much logic in itself so most likely that won't be your bottleneck.
The next part depends on what your intentions are. As I read your question it would appear that you only want to push the transactions into the blockchain and you don't care about whether they get mined or not. But based on your comments I guess your measurements require that the transactions would get mined as well.
So if the transactions should get mined as well your bottleneck will most likely be the blockchain itself. And that really depends on your network setup. As it's a private network, it may work fast but most likely it won't work fast enough. I'm not sure how far you can push the gas limits of a block for example - maybe in theory you can increase the limit enough so that you'd get 15k transactions in a single block but I'm unsure about this. Or, well, I doubt there are any strict restrictions in that sense and you just might get away with it.
Even if you get all your transactions in a single block and someone completes the block (how long that requires depends on your network/nodes) it will only give you certain kinds of measurements. Your network will be very dissimilar to the public Ethereum network. But maybe that's ok for you.
Anyway, long story short, if it's enough for you that the transactions are broadcasted to the network and you don't care about when they are mined then your bottleneck is most likely the node(s) you use for broadcasting. But if you want the transactions to be also mined fast you have to modify the network heavily and make sure the nodes handling the transactions can take in that many transactions.


Set up external storage to SD Card

Question: Just put 64gb Samsung SD Card into my galaxy j7 looking for advice on setup and moving pics and filed from internal.. possible to create widget or how to make a default to the external..help plz
Comment: What, specifically, are you trying to achieve?
Comment: Thanks for a few minutes of your time Dan... I have a j7 its at compacity for its 16gb I put a Samsung SD Card in 64gb and I just need to put whatever I can that's ok for the phone to still function properly onto the SD.. My wife has about 4000 pics of my three daughters as they were growing up.. she wants to send them to me and i just need to be able to out them in the SD.... we are separated so it has to be by phone.. there is not a way to put the SD as default.. I have installed a few apps but dont want to start moving files not knowing.. I'm an idiot and just need my girls baby pictures..
Answer: Settings- storage (name may be different) - default write disk. Select SD card.
Use app like files go to transfer photos to SD

Set up external storage to SD Card


ZigBee and Zigbee Pro interoperability

Question: Will products based on different ZigBee stacks (like the "Zigbee" and "Zigbee Pro" profiles) be interoperable?
Answer: The simple answer is yes, as long as they use the same frequency range and bitrate, as there are multiple options for these in the standard.  This means physical layer interoperability (i.e. if you wrote the code for one or both, the modules should be able to talk to each other), not application-layer interoperability (i.e. any two random devices with a Zigbee logo on the box will not necessarily have anything meaningful to say to each other :)
Answer: This is covered in the ZigBee FAQ:

ZigBee PRO is the primary development choice; therefore, products built with the ZigBee Feature Set can only participate in a ZigBee PRO network as end devices. Due to the wide variety of products able to use ZigBee, interoperability of products is determined by ZigBee standards.
Answer: ZigBee and ZigBee PRO are not different stacks: they are feature sets, and the latter is extended compared with the standard version.
From the same page Nick linked:

ZigBee PRO has a number of optimizations designed specifically for larger networks comprised of thousands of devices.

If you also look at this table:

they are cross compatible, but the PRO version is better optimized for some tasks. The price is higher traffic load and (most likely) $.

ZigBee and Zigbee Pro interoperability


In Samuel Delany's "Empire Star," is there an explanation for Ni Ty Lee's omniscience?

Question: In "Empire Star," the poet Ni Ty Lee has experienced everything that everyone else in the galaxy has experienced.
Because of the time-traveling aspect of the story, and the way that many characters turn out to be the same person, are we meant to believe that in the end there is only one character, and Ni Ty Lee is his/her last incarnation? Is any explanation offered or implied?
The book is so complicated, I'm worried that the answer to this was given and I just missed it.
Answer: I think that NTL is there as a hint that it's a big universe and the same things happen and the same stories are told with different people,  see Joseph Campbell's "The Hero with a Thousand Faces" for example.  I'm not sure I'd like to say more without re-reading the story - it's been a while.


product display image not showing drupal

Question: I have a question about Drupal Commerce (I'm using Drupal 7). I've added a number of products and created a multi-product display for them. I added a product image (it's common for all these products) to the product display. I also have a view of all product displays with images. But when I click and go to the product price and add to cart form, the product image does not show up. What am I missing??? (I did the same on the localhost before and everything worked fine, but probably I forgot to configure something)
Answer: I believe you need to add a relationship to your view between the node and the product display.
Hope this helps...
Answer: You should add the product image to the product entity itself, rather than the product display node.


Replacing the head gasket in a 1993 Mercedes 300ce

Question: Is replacing the head gasket in a 1993 Mercedes 300ce, an expensive repair? I've been told it is better to just replace the engine all together. Is it a tough job for a backyard mechanic or a diy person?
Answer: The Mercedes M103 engine in your 300CE is a proven design, old enough to demonstrate its longevity—lots of them are running around still with 300,000+ miles on them.  The head gaskets are pretty much the only serious weak point.  If the engine was not burning excessive oil (more than a quart every 5,000 miles) or showing other signs of extreme wear before the head gasket blew, it is definitely worth repairing.  In other words, there is no need to buy an entire new engine.
If you buy a head gasket from the Mercedes dealer rather than an aftermarket part, the problem won't come back; the new gaskets are an improved design.  Buy new head bolts from the dealer as well; they are designed to stretch when installed and cannot be reused.
The cylinder head is very heavy and will take at least two people to remove it safely from the engine.  Overheating it probably warped the head enough that it won't seal correctly unless planed on the bottom (this is true of all aluminum heads, not just Mercedes), so you will want to take it to an automotive machine shop to do that.
With the head off on the M103, you have much easier access to the timing chain cover, which tends to leak on these engines, so you can change the gasket there.  Also, you will have to drain the coolant before removing the head, so during the process, use a hose to flush the entire cooling system, and consider replacing any hoses that look old.
When you put the whole thing back together, it's crucial to follow the procedure given in the factory service manual or the Haynes manual for 124 chassis cars to correctly tighten the head bolts down; incorrect tightening will just warp the head and make it leak again.  You will need a good-quality torque wrench.
All in all, it's not too bad a job, but I wouldn't recommend it for a novice mechanic unless assisted by someone more knowledgeable.  Mercedes 124s are wonderful cars when sorted out, though, and the coupes are future collectibles—good luck getting yours back on the road!
Answer: One thing to consider when replacing a head gasket is that your engine's head may have warped ever so slightly when the car overheated (caused by the blown head gasket). If that's the case, it would have to be machined by a workshop.
As for actually replacing the gasket yourself, it's a matter of removing the top part of the engine, scraping away the remains of the old gasket and sticking a new one on in its place. It's a long job, but nothing especially difficult. It would probably take you a couple of hours. Just make sure you have a good quality replacement gasket, a torque wrench and the kids are somewhere where they can't hear you swear.
Here's a youtube video that shows how this is done.
Comment: Agreed, although I'd say it's more likely for the head to warp than the block. The first 'big' job I ever did on a car was replacing the HG, so it is perfectly possible for even a fairly novice DIYer.
Comment: I obviously meant the head would warp :P
Comment: "head" usually refers to the actual valve assembly block, "header" usually refers to the exhaust manifold coming out of the "head".
Comment: I agree it's possible for a novice, but depending on the type of engine, it can be a huge pain to get the parts off you need to get access. If you do it, you'll definitely feel like you have a much better understanding of car repair afterwards! Make sure you have the right torque specs and tightening procedure, get new bolts if needed for your model, and check the head for warping (using straightedge and feeler gauges) if you want to do it right.
Comment: I've never heard "top" nor "header" used to describe the cylinder head in idiomatic American English.  As Mike Saull points out, a "header" is a special kind of exhaust manifold.  "Top end" sometimes is used to mean the cylinder head, camshaft (in OHC engines), and the valvetrain as a unit—as in a "top end rebuild."
Comment: I'll make the edit.


To create a channel on the Lightning Network, do you have to execute an actual transaction?

Question: I'm trying to better understand the Lightning Network.  I was reading this article -- https://medium.com/coinmonks/lightning-network-how-does-it-work-ceeeda8ad21e .  My question is, when two parties create a channel and one or both commit funds to that channel, is the committing of those funds an actual transaction on the Bitcoin network?  That is, can the two parties involved only start using the channel when that transaction has been settled on the Bitcoin network?
Answer: Yes, a channel opening involves creating and signing 3 transactions, and broadcasting just one.
The transaction to be broadcast funds the channel, and spends to a multisig output. It is signed by whomever chooses to fund the channel. When this funding tx receives sufficient confirmation, the channel is considered open.
This multisig output is spent by two commitment transactions signed by both payment channel peers, but not broadcast. Each peer stores its own commitment transaction and only broadcasts it if it decides to unilaterally close the channel.
Comment: Thanks for this clarification.  So this might be really obvious, but in as far as the broadcasted transaction funds the channel and Bitcoin transactions usually take an hour to be confirmed, I assume that means folks can't start using the channel until that confirmation occurs an hour later?
Comment: Pretty much yeah, 6 confirmations or so ...
Comment: Here's a link to a question has a lot of related info about pending channels, the number of confirmations required before using the channel is a configurable option: https://bitcoin.stackexchange.com/q/79580/63872


UK Long Term Standard Visa no longer an option?

Question: Apparently we can no longer apply for a long term visitor visa? The .gov site channels you automatically to the 6  month visa. I've tried going through the older Visa4UK site as well, and it doesn't give the option either. What gives?
This question perfectly describes the problem I'm having, only the answer no longer works.
Answer: It looks like it's still an option for people over 18 years old. This from Gov.uk/standard-visitor-visa (Link below):
"If you need to visit the UK regularly over a longer period, you can apply for a long-term Standard Visitor visa that lasts 2, 5 or 10 years. You can stay for a maximum of 6 months on each visit.
If you're under 18 years old when you apply, your long-term Standard Visitor visa will only be valid for up to 6 months after you turn 18.
Fees
A Standard Visitor visa costs £95.
The fee for a long-term Standard Visitor visa depends on its length:
2 years - £361
5 years - £655
10 years - £822 "
https://www.gov.uk/standard-visitor-visa
Comment: Umm.. 6 months after the applicant turns 18. If he is 10 at the time of the application, the maximum validity for yhe visa will be until he is 18 1/2.
Comment: Yeah, that's what they SAY. But once you actually apply, nowhere does it give you the option to apply for a longer term visa. Frustrating, but I guess I don't have a choice. Six month visa it is. :(
Comment: Strange, but enjoy your six months anyway!


Reduce subset sum to 3SAT

Question: How to do it?
I'm not asking the solution for the proof of why subset sum is NPC, but rather the opposite reduction
Comment: Construct a non-deterministic Turing machine which solves subset sum. Apply the [Cook-Levin theorem](https://en.wikipedia.org/wiki/Cook%E2%80%93Levin_theorem) (actually, to be more specific, [Cook's proof of it](http://portal.acm.org/citation.cfm?coll=GUIDE&dl=GUIDE&id=805047)). Anything wrong with this approach?
Answer: The trick to reducing any NP problem to SAT is 1) writing a subroutine that checks the polynomially-sized certificate, 2) converting that routine to a circuit, and 3) flattening the circuit to CNF using the usual methods.
For example, to convert integer factorization to SAT, you would write a routine that multiplies two $n$-bit multipliers producing a 2$n$-bit result.  Convert the routine to a circuit, then convert the circuit to CNF.  Then add simple declarative CNF clauses that force the $2n$ output variables of the circuit to match the bits of the integer that you want to factor.  The resulting CNF instance will be satisfiable only if a bit pattern for the two $n$-bit numbers exists that when multiplied together produces the 2$n$-bit number you want factored.  (If you want trivial solutions excluded then you also need to add two extra CNF clauses that demand the most significant $n$-1 bits of each multiplier are not all zero.)
Subset sum is a bit more intricate.  You need to write $n$ routines, each of which returns a particular one of the $n$ integers of the problem set or zero depending on the setting of a parameter bit.  These routines feed input into another routine you wrote that sums all $n$ of its inputs and outputs the result.  Convert all this into a circuit whose inputs are the parameter bits and whose outputs are the result of the addition routine.  Convert the circuit to CNF.  Add declarative CNF clauses that force the output variables of the adder routine to match the bits of $k$, the number a solution must sum to.  The resulting CNF instance will be satisfiable only if there exists a bit pattern of the parameter bits selecting a subset of the problem set that sums up to $k$.
Comment: We also want CNF clauses that force the OR of all parameter bits to be true, to avoid getting the trivial "choose nothing" solution.
Answer: Usually, there are no intuitive or enlightening reductions between problems in different problem domains.
The proof that 3SAT is NP-complete is essentially by writing a formula that says "This NP Turing machine accepts this input."  For other problems about logical formulas, you can often translate the formula into a 3SAT instance.  Sometimes, you can express problems in other domains as 3CNF formulas: for example, you can do 3-colourability by having variables for each combination of "vertex $v$ has colour $q$" and write a formula that says that each vertex has exactly one colour and adjacent vertices have different colours.
However, usually, when you're faced with a problem from a completely different domain, you can't do much better than say that subset sum is in NP so it's decided by a Turing machine that I can express as a 3SAT instance.  Perhaps you can come up with a less generic reduction, but it probably wouldn't teach you anything.

Reduce subset sum to 3SAT