HDD connector for laptop hardidsk to PC

Question:
This is the Laptop's Hard Drive That I want to connect to my PC.

This is the existing Hard Drive Cables in my PC.
Which Cables Should I purchase to connect HDD to my PC ?
Comment: It's hard to tell from the picture - could it be a PATA connector? https://en.m.wikipedia.org/wiki/Parallel_ATA
Answer: That's a custom connector, specific to your brand of laptop. It should be possible to pull it off to reveal SATA power and data connectors underneath, which will work with your existing cables.

HDD connector for laptop hardidsk to PC


Synchronous Generators: Full load and No load

Question: When referring to synchronous generators, what do they mean by "operating at no load or at full load"? Can I connect a load that is larger than full load?
Answer: Of course you can connect a load that's larger than full load.
The data sheet tells you what happens at full load. Unfortunately, the data sheet probably doesn't tell you what happens at more than full load. You would have have to do the experiment to see whether it failed to self-excite into it, exploded, blew a fuse, tried then shut down safely, or how long it took to overheat.
There is a school of hobby engineering that assesses maximum ratings by ignoring the data sheet and turning it up until it explodes, then backing off a bit. Sounds like you adhere to this teaching. Professional engineers tend to stick to the data sheet. Often the manufacturer has spotted something in the months or years of development and qualification that the user hasn't yet.
Comment: No, it means the maximum safe current permitted by the manufacturer is flowing.
Comment: ... with the emphasis on 'safe'
Comment: Just one thing...when a generator is said to operate at full load....does it mean that maximum possible current is flowing in the circuit?
Answer: Full load
It is the maximum amount of VA flowing through the equipment at full load under specified conditions.
Rated Load
Rated load/VA is the load specified in the nameplate of the instrument as specified by the manufacturer. This is also the rated current that a machine can carry without any damage.
Nominal Load
The maximum VA under nominal or rated voltage and power conditions. This is mostly the same as rated current.
Note: if you exceed Maximum load, depending on how much, a number of effects my occur.

The load is increased --> current draw is increased BUT there is still electromagnetic headroom. Generator heats up faster than literature states as it is now operating outside of rated condition
The load is increased --> current draw is increased but this time it is beyond the EM capability. EM stall starts to occur: reduction in frequency generated, reduction in main exciter if via a wound rotor (maybe with a main exciter for XFMR coupling).
Answer: With a synchronous generator, it is important to distinguish between full-load current and full-load power. Power = Voltage X Current X Power Factor. Neither the full-load current rating nor the full-load power rating may be exceeded without adverse consequences. That means that the power factor can not be lower than some minimum rating when the current is at the maximum rating. If a single-phase generator is rated 400 volts, and 10 kW at 0.8 Pf, the maximum current at 0.8 pf would be 10,000 W / (400 V x 0.8) = 31.25 A. If the power factor is 1.0, the maximum current would need to be reduced to 25 A to avoid exceeding the maximum power rating: 10,000 W / (400 V x 1.0) = 25 A.
The maximum current is the current that the generator can safely carry without overheating. The maximum power may be determined by the rating of whatever prime mover is driving the generator. The excitation and factors affecting the stability of the generator may also be limiting factors. The limiting factors can be found by examining the generator performance curves.


Is making faster military fighters even practical?

Question: I was curious after reading a book on Cold War plane development about the Soviet ideology of making increasingly powerful jets that could break Mach 3 and so on. With the advent of BVRAAM's such as the Meteor and lasers that are already being scaled down, what are the advantages to increasing the top speed or cruise speed of a fighter jet?
Comment: [Related](https://aviation.stackexchange.com/q/48674/62), maybe a dupe?
Comment: Related to "why are there no Mach 4 fighters": https://aviation.stackexchange.com/questions/44530/why-are-there-no-mach-4-fighter-planes/44595#44595
Comment: No I already know how the practical speed barrier prohibits some advances, but I was curious as to if increasing speed significantly was possible, would it strategically/tactically be advisable?
Comment: Fast interceptors is still useful if the defense side has a large attack surface and not a lot of alarm time, .e.g. when the interceptor arrives the attacker might have already dropped the payload. But after the cold war the only place that still suffer this kind of threat is probably Japan and east Europe which seem to have chosen not to envelop a effective high speed interceptor.
Answer: In the 1960, faster fighters were seen as desirable as they could outrun 1960s technology missiles to an extent (see the reports of SR-71s being fired on but never hit by SAMs). Of course, missile manufacturers saw this and developed faster missiles and longer-range radars to negate this advantage. And as it is much easier to make a missile faster than it is to make a large aircraft faster, that's an arms race the airplane manufacturers always lose.
While high speed allows you to outrun missiles, it also reduces maneuverability: at Mach 3, a constant-G turn will be much larger than turning at the same G level at Mach 1.
Answer:
what are the advantages to increasing the top speed or cruise speed of
  a fighter jet?

It's often thought that speed is used to avoid attack, but that is rarely successful. It's far easier to make a faster fighter or missile than a faster, say, bomber. This has gone back and forth over the years, see schellbomber for instance, but invariably the defense had the easier job - especially once they had radar and interceptions were arranged in front.
The real reason speed is useful, especially in the 50s and 60s, was that the interception process itself was manual. So if the guy on the ground has a radar with a 200 mile range against your bomber and you're flying Mach 3, you're going to be overhead in 5 minutes and disappear in 10. That leaves very little time for the operator to arrange an interception. If the interceptor starts on the ground, it's not going to happen, period.
That, of course, changed with the introduction of SAMs. Now the only need for the operator is to figure out roughly where you're going and alert the closest SAMs along that line. Five minutes is lots of time for them to get ready.
There is, of course, the advantage of confusing the defense network as a whole; Moscow is maybe 15 minutes from the coast in a B-70, and that doesn't leave lots of time to get prepared. But in the era of ICBMs, that too is enough time.
And so speed sort of went away and was replaced by low-level flying, jammers, SRAM and so on. If you're going to blast your way through the defenses with SRAM, doing so quickly doesn't really offer much of an advantage, the missile is going much faster than you ever will.
But all that is old is new again, and speed is once again showing some advantages. In the case of the F-22 the idea is simply to have enough performance that the combination of altitude, speed and stealth/detection range keep you out of the lethal volume of the missiles below you. So against something like the S300, the missile has excellent performance and can shoot you down, but it will only see you at short ranges and you're way up in the air, so by the time they get a tracking solution you're already out of range. That's significantly more difficult to pull off if you're flying 30% slower.
Comment: What does SRAM mean ?
Comment: Short Range Attack Missile, but the paragraph makes hardly sense to me. Probably it means, that your own speed doesn't matter a lot, when you are at least capable to launch it within some more distance than a bomb?
Comment: Basically if you're going to blow up all the defensive emplacements it doesn't matter how fast you fly to them as long as the missile gets there first.


Are the vocal melodies on the first staff part of the same chord progressions as the piano accompaniment on the bottom?

Question:
Are all the notes in each box part of the same chord?
Comment: Are you asking specifically for this example alone (no is the answer) or generally? (No again!)
Comment: Please try not to ask essentially the same question twice.
Answer: Knowing the make up of chords will help answer. Take the third box (bar or measure). G add 2. That's G B D and A. Those notes are there, but also there's an E and an F#. So, obviously, the answer is no. The last bar chord is Em7b5, made up from E G Bb and D. There's also F# C and A. Answer no again.
However, thinking past the question's wording, should it mean generally, the same applies. In most given bars, there will be notes from the accompanying chord, with often two or three passing notes, used as 'stepping stones' to get from one chord tone to another. Merely using chord tones will work, but the melody won't be as interesting, usually, if that's the case.
Answer: No. There's a C# in the first box, and that's not in the D chord (D-F#-A) the first box is labelled with.
There are also a D and an E in the second box, neither of which are in the F#m chord (F#-A-C#) the second box is labelled with.
Actually, you can assume that the topmost melody is harmonically ahead of the boxes by an 8th note.
Comment: The melody has been 'pushed', as happens in a lot of pop songs.
Comment: ' you can assume that the topmost melody is harmonically ahead of the boxes by an 8th note' - for the OP's benefit, presumably you're talking about this particular piece, rather than a general rule?
Comment: @topo morto, yes, that's for this particular piece only.


The Subject is the "geborene Sohn" ... so is "der am 23. Oktober 1973 in Hamburg" a relative Clause?

Question: Dabei entstammt der am 23. Oktober 1973 in Hamburg geborene Sohn eines Arbeiters und einer Schullehrerin einem fast schon bürgerlichen Milieu, geprägt von der ersten Generation Einwanderer.
Answer: No, it's all one lengthy subject.

Dabei entstammt der am 23. Oktober 1973 in Hamburg geborene Sohn eines  Arbeiters und einer Schullehrerin einem fast schon bürgerlichen Milieu.

Let me rearrange it:

Der [...] Sohn [...] entstammt dabei einem fast schon bürgerlichen Milieu.

German speakers aren't afraid of such lengthy subjects and objects.
Comment: Ich schon. Nicht im Umgang damit, aber in der analytischen Identifikation.
Comment: Attribute des Adjektivs *geboren*.
Comment: *geborene* is an attribute of *Sohn*. *am 23. Oktober* and *in Hamburg* are attributes of *geborene*.
Comment: It would still have been interesting to know what grammarians call "am 23. Oktober 1973 in Hamburg geborene" in this sentence.
Answer: Analysis on top level:

dabei
Konsekutives Konjunktionaladverb (consecutive conjunctive adverb)
This word links the sentence to what has been said in the sentence before. (This previous sentence is not available here.)
entstammt
Verb (verb) (the singular, 3rd person form of »entstammen« in Gegenwart = Präsens (present tense))
What ist the action? What is going on in the sentence?
In every German sentence that is a statement (i.e. neither a question nor a command) the verb has to stand on position 2.
der am 23. Oktober 1973 in Hamburg geborene Sohn eines Arbeiters und einer Schullehrerin
Subjekt (subject)
Who is performing the action?
Here we have 14 words, which together form one noun phrase (in German: Nominalphrase), and this one phrase is the subject. The head word of every noun phrase is a noun (that's why its called noun phrase), and the grammatical properties of this head noun define the properties of the phrase.
In this example the head word is »Sohn« (son). It is singular and masculine and stands in nominative case, and so the complete noun phrase also is thought to be masculine, singular and in nominative case.
Since there is nothing else in this sentence in nominative case, and because every sentence must have a subject (with rare exceptions), end because the only case in which the subject can appear is nominative case, this 14 word noun phrase must be the subject.
einem fast schon bürgerlichen Milieu
Dativobjekt (object in dative case)
The verb (on position 2) needs some complements. Each verb needs its own set of complements. One complement, that every verb needs, is the subject. But all other complements depend on the verb.
The verb entstammen (to stem from) needs a subject, that tells us who is stemming from somewhere. And it needs a second complement, that has to stand in dative case, that can tell us the source, i.e. from where the subject stems. This source is this object here.
geprägt von der ersten Generation Einwanderer
Nebensatz (dependent clause)
This is Verberstnebensatz (dependent clause with verb at position 1) that is derived from a relative clause (»das/welches von der ersten Generation Einwanderer geprägt ist«)

The parts of speech on the positions 3 to 5 can all be separated deeper into their parts, but according to your question, I only do this for the subject, i.e. the part of speech o position 3:

der
The article of the head noun (which is »Sohn«)
am 23. Oktober 1973
A Präpositionalobjekt (prepositional object), here in the role of a temporal attribute of the adjective (which is »geborene«)
in Hamburg
Another prepositional object, but this one is a local attribute of the same adjective
geborene
An adjective (the weak declined singular masculine positive form of »geboren«), which here is used as an attribute of the head noun
Sohn
The head noun of the noun phrase. Masculine, singular and in nominative case
eines Arbeiters und einer Schullehrerin
A list with two items. All items in the list are of the same kind, they are genitive attributes (genitive objects, used as attributes of the head noun)

Both prepositional objects consists of a preposition and a dative object:
Note, that »am« is just a short form of »an dem« (like don't = do not)

an dem 23. Oktober 1973
The word an is a local preposition, the rest (dem 23. Oktober 1973) is an object in dative case
in Hamburg
In is a local preposition, Hamburg is also a dative object.


Unable to import fbx files

Question: Having difficulty importing .FBX files into blender.
i select .fbx file and hit import and nothing appears in the editor/scene.
must be a pretty silly question but ive never had this difficulty before.
if anyone has any pointers they would be greatly appreciated.
thank you!
Comment: Could you post this .FBX file?
Comment: http://tf3dm.com/3d-model/apple-iphone-6-3d-model-35596.html
Comment: but it seems to be the same for other files as well including collada and obj :/
Answer: .FBX import is fine, just scale of the object is really small.
After import press S then type 1000.
You can alway check if something is on the scene in Outliner.
Comment: Yes, and in the Outliner, there may be nothing at all after an FBX import. With no error message. I had this happen to me today. The only thing which worked reliably for me was the OBJ import. But I've looked at the contents of an OBJ file and it doesn't actually contain a whole lot of information.

Unable to import fbx files


Adding a CSS sheet to my CMS page Magento2

Question: I am creating a CMS page, what is the proper way to add a style sheet for this page, through the Layout Update XML field like this <css src="Magento_Contact::css/styles.css"/>, or do i put the css in the modules css/source/_module.less sheet (this seems to apply the css for this page on all pages across the site which is unnecessary and unwanted)?
Answer: Yes you are correct _module.less will add to all pages, XML within "design tab -> Layout Update XML" (as you have discussed on CMS pages) or within theme however will allow you to target individual pages or types of pages.
Adding CSS to CMS page should be doable by adding below code to "Layout Update XML":

    <css src="css/cmsstyles.css" />

cmsstyles.css should go in your theme within web/css folder.
I have seen a few people having issues however with this on certain Magento version however this works for me currently on Magento 2.1.7.
See here for a similar question with many answers:
Adding CSS to a CMS page using Layout Update XML


How to transfer music (purchased from Google Play Music) from Android to Windows?

Question: How do I transfer music from my Android phone to MS Windows? It only shows me the songs from the music app and not the Play Music app with the songs I've purchased.
Answer: You should be able to access all of your Google Play music on a computer: Google Play Music. You can download any purchased music though the browser. For instance: I purchased an album from Google Play and it is available for download using the website on the computer (see image).
Hope this helps]2
Answer: What I did was go to Google Play and downloaded my music. After that the little download bar shows up (bad at explaining things). Than I just hit Save As to my music and... Shazam! my music is saved to my laptop. I hope this helps.
Answer: most probably the songs that you have downloaded using google play music app are drm protected, that could be the reason you are not able transfer them to your laptop.


Can i have two low points in a story?

Question: It's a TV episode. the heroes reach a low point where they think they're defeated, one of the characters has an idea to make things work, they follow him and it eventually leads to a combat scene, they lose and are hopeless again, but another character has another idea, it doesn't involve combat, just a montage of the events, and it works. Is it considered bad structure to have 2 low points? I really think both the first and the second have essential scenes that i would be sad to throw away.
Comment: What do you mean by a 'montage of the events'?
Answer: I'd say yes. That first idea is a "Hope Spot", where the audience is led to believe things might work out after all, only for them not to. It's a fairly common technique (obligatory TV Tropes warning).
However, I feel like making the resolution a montage sequence is a bad idea. You're making us watch the heroes lose twice, and then not showing us how they win! So I'd do it the opposite way round: don't show the first idea's failure. Show the character saying, "I've got an idea, we can still make this work!", then smash cut to the end of the fight, where they've just been defeated again. You can still have your scene of them being hopeless and despairing, and then you can use the time you saved to show the resolution in more detail.
Comment: Thanks for your help, i guess your suggestion does make far more sense, i'll work on writing it in.
Answer: It is not bad structure, it is in fact common advice: Try & Fail, Try & Fail, Try &Succeed.
It is common advice to writers because many stories have succeeded using this formula. Look at the Die Hard movies or 007 movies; the villain escapes several times before they are finally caught or defeated. The same was true for 24 Hours. It is not unusual in Romantic Comedy, or other action adventure.
That said, while it is fine that another character has a new idea that does not involve battle, I strongly discourage glossing over this idea with the equivalent of "telling" instead of "showing". If anything should be visualized it is the details of bringing the reader to the final victory.
Montages are reserved for compressing a lot of boring work by the characters into something informative and clever. Preparatory work like building a new device, painting and outfitting a car to be a fake cop car, "thinking", practicing a move, rehearsing a scene, training up (think the Rocky montage), etc. You can see this kind of montage in something like Ocean's Eleven or many other heist films.
Pacing and music can be an important part; I have seen montages with every scene less than half a second long, others where the scenes are several seconds long. Scene length depends on what each scene is supposed to say; with very fast scenes the information is primarily visual; like the sights seen on a long trip. In something like Ocean's Eleven, the prep montages are slower because they are solving problems or rehearsing stuff.
The purpose of such a montage is to convey a lot of information fast in a cinematic way; but the information conveyed should still be important to the story; either character building (seeing a character moving through the world), or they are there for plausibility: Ocean's Eleven and Rocky feel more plausible because of their montages, they are "proof" of intense preparation and obstacles that have been overcome.
If that is the kind of montage you mean, then fine. But you need an extended several-minutes scene at the end, when it all comes together, for the finale.
This is because montages ONLY convey information, they are very poor at conveying emotions, and the finale must be an emotional victory of some sort, a permanent change of fortunes or something like it. The villain or obstacle is finally defeated. A 60 second montage of a man trudging across the Sahara and slowly dying is fine, but it can't include him getting out of the Sahara, that is a SCENE.
Hopefully that makes sense to you!
Answer: I think it's fine to have an up-down-up-down structure, but that one of the lows, probably the second one, should be significantly "lower" than the other one.  Otherwise it does just feel like a repetition.  Maybe experiencing the first low helps in some way in overcoming the second.  Or the first foreshadows the second.  But they should be discernibly different, and each should play a role.

Can i have two low points in a story?


27" iMac (fall of 2010) won't shut down

Question: Whenever I try to shut down my iMac (3.2 GHz Intel Core i3, running 10.7.3), it closes out all programs, goes to the gray screen with the spinning ball and just hangs there.  This occurs in restart or shut down mode.  Any thoughts?
Comment: Can you start up in verbose mode (http://support.apple.com/kb/HT1492) and take a photo of what it hangs on when you shut it down?
Comment: Happens to me on both my macbooks (not every time, though).
Comment: Create a small partition in the extra space on your drive, and load a fresh copy of OS X onto it.  If the problem also occurs there, it's likely hardware related.  If the problem doesn't occur there, something is wonky with your main installation.
Comment: In case anyone comes across this old issue, this solution seems to work for most (including me just now). https://apple.stackexchange.com/a/245194/1195
Answer: Zap the PRAM and reset the CMS
A small amount of your computer's memory, called "parameter random-access memory" or PRAM, stores certain settings in a location that OS X can access quickly. The particular settings that are stored depend on your type of Mac and the types of devices connected to it. The settings include your designated startup disk, display resolution, speaker volume, and other information.

Shut down the computer.
Locate the following keys on the keyboard: Command ⌘, option, P, and R. You will need to hold these keys down simultaneously in step 4.
Turn on the computer.
Immediately press and hold Command+option+P+R. You must press this key combination before the gray screen appears. Continue holding the keys down until the computer restarts, and you hear the startup sound for the second time.
Release the keys.

Resetting PRAM may change some system settings and preferences. Use System Preferences to restore your settings.
How to Reset Your Mac's SMC
The method for resetting your Mac's SMC depends on the type of Mac you have. All SMC reset instructions require shutting down your Mac first. If your Mac fails to shut down, try pressing and holding the power button until the Mac shuts down, which usually takes 10 seconds or so.
Mac portables with user-removable batteries (MacBook and most MacBook Pros):

Shut down your Mac.
Disconnect your Mac portable from its MagSafe connector.
Remove the battery.
Press and hold the power button for at least 5 seconds.
Release the power button.
Re-install the battery.
Reconnect the MagSafe connector.
Turn your Mac on.

Mac portables with non-user-removable batteries (MacBook Air and some late 2009 MacBook Pro models):

Shut down your Mac.
Connect the MagSafe power adapter to your Mac and to a power outlet.
On the built-in keyboard (this will not work from an external keyboard), simultaneously press and hold the shift+control+option+power button. Release all keys at the same time.
Press the power button to start your Mac.
Mac desktops (Mac Pro, iMac, Mac mini):
Shut down your Mac.
Unplug your Mac's power cord.
Press and hold the Mac's power button for 15 seconds.
9 .Release the power button.
Reconnect your Mac's power cord.
Wait five seconds.
Start your Mac by pressing the power button.

Alternative SMC reset for Mac Pro: If you have a Mac Pro that isn't responding to the normal SMC reset as described above, you can force a manual SMC reset by using the SMC reset button located on the Mac Pro's motherboard.

Shut down your Mac.
Unplug the Mac's power cord.
Open the Mac Pro's side access panel.
Just below the Drive 4 sled and adjacent to the top PCI-e slot is a small button labeled SMC. Press and hold this button for 10 seconds.
Close the Mac Pro's side door.
Reconnect your Mac's power cord.
Wait five seconds.
Start your Mac by pressing the power button.
Answer: Try booting into Safe Mode and see if the shutdown issue exist.
You can also open Activity Monitor in the Utilities folder. Select All Processes from the Processes dropdown menu. Click twice on the % CPU column header to display items in descending order. If you find a process using a large amount of CPU time, then select the process and click on the Quit icon in the toolbar.  Click on the Force Quit button to kill the process.
Causes could be:

One or more processes or applications that are corrupted and not able to shutdown.
Problematic Login Items under the Accounts preferences Login Items tab.
Incompatible third-party extensions and/or preferences.

Hope that helps.
Answer: If you have any attached external TB, FW or USB devices other than keyboard & mouse, dismount them first, (if mass-storage devices,) then shutdown & see if it completes.
I have a client (my Mom) whose Mac Mini had the same symptoms and found that she'd kept a USB thumb drive physically attached & had forgotten about it. It had been there for some months, but at some point something happened to the drive (out of space? corrupted directory?) and when it was removed for troubleshooting, the Mac shut down normally. She'd gotten into the habit of forcing the power-off, too. Ouch.

27" iMac (fall of 2010) won't shut down


What is the purpose of MD5 hash in downloading apps?

Question: I have never checked and compared the MD5 hash to the real MD5 hash at programs homepages.
Programs which I have downloaded have always worked.
Is it possible that someone can put their own code during downloading?
Answer: A hash provides a (sort of) unique identifier for a file based on its contents. With lossy connections and poor transmission methods, as well as malicious file copies floating around, a hash provides a way of proving your file is the same file you tried downloading from the server.
You validate it by hashing the copy of the file you got, and seeing if the hashes are the same.
People can inject nasty code, change out the file being downloaded, or you could just get a corrupt download.
Comment: It's theoretically easy and rarely done in practice.  However, if it happened to you, you would be upset. So check.  Technically, it's a pretty poor security measure -- if a malicious attacker can replace a binary on some server, they can replace the checksum published on the same server to match. There are various schemes that distribute the checksums, so you can compare; but in practice it's mostly a precaution against incomplete downloads.
Comment: How much are there this kind of attacks in the web? I would like to know the probability.
Comment: Ubuntu's package manager (based on apt) does two things. Firstly, it verifies a master list of all packages, which are signed used GnuPG by a key the system knows to trust. This package list contains checksums (SHA1) of each package that is available to download.

PKI methods (such as GPG) are much better than simply providing the hash. You have no idea who provided the hash, but *may* be able to ascertain who controls the signing key.
Comment: Does Ubuntu's package manager check the Hash code automatically?
Comment: It's -incredibly- unlikely. Basically, you'd have to have someone on your own network or someone attacking the server to accomplish this. It basically doesn't ever happen - but allllways check hashes whenever they're provided. It's a very good practice, and very good idea for security-critical environments.
Answer: In terms of corrupt downloads, it's pretty rare. I don't think I've ever had a corrupted download except if it somehow got truncated and the error not reported (old FTP clients back in the day).
There might be some security benefit if you're downloading from a mirror, and you trust the real site (which publishes the MD5) more than you trust the mirror (which might be out of date, or evil, or buggy, or pwned, or something, and so might a caching web proxy between it and you). Pretty unlikely situation, though, since there's normally no reason to think that the main site is any more or less trustworthy or secure than the mirror. Still, it's a second opinion.
I don't usually bother checking published checksums unless there's a particular reason to think that they are correct and the download isn't secure (e.g. the checksum is on an https URL and the download isn't). If you're worried about evil-doers then you need signing, not just an insecurely-transmitted checksum.
I do occasionally use the hash-based virus scan reports at virustotal, though. I guess a published MD5sum could allow you to virus-check the file before even downloading it, and then you'd have to check the sum after download to confirm that the value you virus-checked really was for the file you downloaded.
Note that MD5 checksums are not secure if the evil-doer generates the genuine file as well as the dodgy virus-loaded one. It's possible to generate MD5 collisions, although there is not (yet) a full pre-image attack. Anyone serious about security has switched to SHA256 sums where possible. Which is less than you might hope, for legacy and resource reasons.
Answer:
Is it possible that someone can put
  their own code during downloading?

Yes. If the download is done via unencrypted HTTP, then it's being routed through a number of networks, and there most definitely is an opportunity for people to manipulate it and insert a trojan or virus.
And this is exactly the goal of the MD5 checksums for downloads, though this is of course not perfect security, since the checksum may be manipulated in the same way. But it would require more effort and coordination on the part of the attacker.
All in all, this is not a very common problem though, since there are other vectors of attack that are currently much more useful for bad guys (mainly webbrowser vulnerabilities).
Comment: @Michael: How often do you get corrupted files? Do you ever check MD5 yourself?
Answer: File can be checked if it is corrupted. Thats all I think.
Comment: So it is not a security measure.
Answer: An MD5 hash is a form of validation. If a single bit in the file is different, the provided hash will not match the one generated from the file you downloaded. This alerts you to an error in transmission or foul play (rare).
Answer: In addition to enabling you to be sure you got the code you tried to download (it wasn't corrupted either intentionally or accidentally), if you check the hash, the practice of including hashes when publishing code is good social hygiene.  Since people who share or sell software often include hashes with their code, and we believe that some people routinely check them (because some download tools do it automatically) crackers will find this to be a less useful way of spreading malware.  Therefore, those who only check the hash on security-critical software, or those who never check can have more confidence that the software is what it purports to be.  If crackers tried to start injecting viruses or trojans into often-used download sites, they would be detected pretty quickly, and the attack repaired and publicized.
So, you can help everyone by occasionally checking, and even if you don't, the presence of the hashes should provide some reassurance that the code is probably as the author intended it, and the same code downloaded by many other people.
Answer: It basically answers the same question as authentication - whether the one who says he is the one is actually the one. It helps you to make sure that the program you've downloaded is actually what author is provided in the first place and was not tampered on the way from the vendor all the way through the maze of the internet into your desktop.
Answer: I check md5 most of the time. Although maybe just once or twice, yes, I did get corrupt downloads.
If you download something, check its md5 and store along with file, it may also be a way later to check if the publisher has secretly changed the file without telling it to anyone.
Answer: Complete waste of time.
A hacker would change the hash as well as the binary so it is only a security measure against incompetent hackers.
Most downloaded binaries are compressed with built in error checking, so the hash achieves precisely nothing which is why I've never seen anyone besides geeks actually use them.
Now a digitally signed hash used by a package installer is something different and worthwhile.


What front derailer and shifter that can be used with a shimano cranket set FC-M610 (48-36-26 AL gears)?

Question: I want to build an MTB and have this new FC-M610 crank.  What front derailer and shifter that can be used with a Shimano crankset FC-M610 (48-36-26 AL gears)?
Answer: Here's an indispensable resource for anyone doing a build with Shimano parts: Shimano Compatibility Chart.  This specific link is a page for Shimano Trekking/Mountain front drivetrain compatibility and lists the appropriate part numbers for the front crank, front derailleur, front shifter and bottom bracket that will match well with each other.  As you can see at the linked web page, there are around a dozen compatible front ders and shifters that are listed as straight compatible with the 10 speed triple crankset, FC-M610. Other model numbers will work (see below), but you need to be sure that the derailleur cage is large enough to match the curve of the large chainring and also designed for a triple crankset.
Typically, the way Shimano model numbers work is the higher the starting numbers, the higher the quality and, of course, price. A few years ago, they somewhat changed their numbering system going from 100's (ie: M610) to 1000's (equivalent but a little newer would be the FC-M6000).  I mention this to avoid any confusion about higher number, higher quality.
So the compatibility chart gives the company's "best match" products, however there are numerous options that will work and work perfectly especially with front drive trains.  Because the front shifter cable pull is the same between speed classes, a shifter marketed as for 9 or 11 speed will work for you. It will need to be a triple front shifter.  Many of the newer and upper tier models have a selector switch that make the shifter either 2x or 3x so they're a little more versatile should you want to change things up and go to 2x at some point.  For the front derailleur, a triple front derailleur from 9, 10, or 11 speed classes will work well when set up correctly. You can get a little more chain noise with an 11 speed derailleur since the cage is narrower than a 10 speed front der.  For example, I bought the smaller FC-M610 (42-32-24) and installed it into my 9 speed drivetrain (M590 shifter and M510 derailleur) and it worked great. Today my hardtail sports a 2x10 speed XT/XTR  drivetrain with the front der being an 11 speed FC-M9020.  As long as one doesn't go more than +/- 1 speed class with front drive components {that 10 speed crankset will work well within an otherwise 9 or 11 speed drivetrain), the system that's set up correctly will function perfectly.
Answer: Every Shimano "touring/trekking triple" works. By "touring/trekking", I refer to front derailleurs that are intended for cranksets that have 48 tooth big ring as opposed to "MTB triple" front derailleurs that are intended for triple cranksets with 42 tooth big ring.
As for shifters, every friction shifter (such as bar-end front shifter) and every "MTB triple" shifter works. So drop bar STI shifters won't work. However, you aren't building a road bike so that shouldn't matter.
Most likely you want to select the shifter based on the rear derailleur and use a matching front shifter.


Whatsapp, Keeping the number on the new phone but without the old sim card

Question: Whatsapp, Keeping the number on the new phone but without the old sim card.
Ok the situation is I love my old number and to be honest don't want to ask everybody to change my number again and again.
But I do not have the old sim card, and that bums me out. If there is any way to achieve this?
Comment: On a new device WhatsApp generally ask you to [verify your phone number](http://www.whatsapp.com/faq/en/android/20970873) by SMS, which will be a bit difficult without the SIM.
Answer: Whatsapp checks if there's a sim card installed at the time of boot.
So as long as you have a sim card installed, it shouldn't be a problem to your whatsapp account (The old one)

I've switched sim cards and it hasn't affected my whatsapp account.
The problem of verification arises when you boot your phone without a sim card.
Answer: You could move your phone number to your new sim card and just type it in WhatsApp, I did that. WhatsApp will ask you for your phone number and once you type it in it should let you log in without a problem. (It worked for me).


A Latin text with dependency tree

Question: I am looking for a Latin text that has word by word English translation and explanation. I mean after the translation, it explains that this word has ablative case and that has nominative or this verb has perfect tense and that has imperfect and all related explanations. Something like dependency grammar.
Is there any?
Answer: Try "Completely Parsed Cicero" by Maclardy. It´s on Amazon.
There is: "Caeser Completely Parsed" by James B. Finch.
Back in May, I couldn't find this though knew it existed. Price fluctuates between £30-94--beware.
Alternatively, it's on the net, for free: "archive.org/details/CommentariesOnTheGallicWarCaeserCompletelyParsedBook1"
There is: "Translating Pliny's Letters About Vesuvius part 3" on site: "quemdixerechaos.com/2012/11/28/translatingplinypt3"
Comment: It is exactly what I want
Comment: The link to Caesar is https://archive.org/details/CommentariesOnTheGallicWarCaesarCompletelyParsedBookI with I, not 1.
Answer: There is a project called The Ancient Greek and Latin Dependency Treebank, which has done dependency trees for some Greek and Latin texts. There is a document explaining the project here. It seems it does not contain English translations, but if you combine their work with a dictionary, or an English translation of the text, you might get further.
There are three similar projects listed here.
All these projects are open-source and community based, so you could suggest the option of translation or contribute with it yourself.
Notice however that, as far as I know, it is not always possible to do word-by-word translations from Latin to English. Also, the word order in English might not correspond to that in Latin (which has no compulsory order). So maybe, what you are after doesn't really exist (and wouldn't be totally helpful either).
Comment: Regardless of the meaning of sentence after word by word translation, it is useful to know which literal or maybe metaphorical meaning of each word is signified in a sentence.
Answer: There is Index Thomisticus, a treebank consisting of work of Thomas Aquinas. It is a free resource under a Creative Commons licence.

A Latin text with dependency tree


How is it on some removable media, when enabling/disabling password protection the changes happen immediately?

Question: For example I have a WD Passport external hard drive. After installing WD security I can enable and disable password protection, however the settings basically get applied instantaneously. Does this mean encryption is not actually happening? If not, is there any point in using a password?
Answer: It is possible to achieve an "instant password change" with an encrypted disk. The idea is that the disk is really encrypted with an internal secret key K. K is a fat, random key that you never see; it was generated when the disk was first powered, and it never changes. K is then stored in a specific slot, encrypted with a second key K', which is derived from your password. When you unlock the drive with your password, the disk firmware recomputes K' from your password, then decrypts K, and then uses K to read and write data to the disk.
When you change your password, K is reencrypted with the new K', but that's fast because K is, say, 128 bits, not 128 gigabytes.
A disk which does encryption that way also often offers a fast "wipeout" feature, by the simple expedient of generating a new K: the previous K being lost, every contents which were encrypted with K (the whole disk) are as good as cleared. (Thus, "K never changes" is not completely true; rather, K does not change when you change your password.)
Now this does not mean that your specific disk uses encryption, only that it could still use encryption, even if it offers fast password changes. There indeed are disks with "password protection" which is only a simple firmware-based lock, without actual encryption of the data, and that can be bypassed by changing the electronic board. If unsure, try to obtain the disk specs from the manufacturer: if actual encryption occurs, then the manufacturer will state it proeminently on the disk datasheet.
Comment: Where *K* never changes, it's somewhat confusing to read that *K* is re-encrypted – because I think of encryption as changing something.
Answer: Presumably it doesn't decrypt the drive just changes the password to one the drive knows internally (probably blank).
I.e. the actual data on the disk platters is encrypted regardless of whether a password is set, but the key which it is encrypted with is not.
I have no specific knowledge of how WD Passport encryption - I am just noting that the instant encryption/decryption is not necessarily suspicious.
Answer: How secure is WD MyPassport lock
Your data is not encrypted regardless of setting a password or otherwise
Comment: zed - if you read Tom's post you would see that what you are saying is incorrect. Please read the other answers before you post.


Why can every prime number be written as 6k±1?

Question: I want to know how to be sure that each prime number can be written in the form $6k±1$. How I can find the prime number that exists after a composite number with this property of prime or other properties of it?
Comment: Could you please clarify what you mean by the second sentence in your question? Do you perhaps mean that, given a _composite_ number of the form $6k±1$, you want to find the smallest prime greater than it? (FWIW, I know of no way substantially better than just generating successive numbers of the form $6k±1$ and running a primality test on each of them.) Or something like that?
Answer: I am not sure if this question should be considered on topic here, but I will answer anyway.
Theorem: All prime numbers larger than $3$ can be written as $6k+1$ or $6k-1$ for some natural number $k$.
Proof: The remainder of a number modulo $6$ is between $0$ and $5$. If it is $1$ or $5$, the above criterion holds. It remains to show that, if it is $0$, $2$, $3$ or $4$, then the number can not be prime. It is easy to see that, for remainders $0$, $2$ and $4$, the number must be divisible by $2$; for remainder $3$, it must be divisible by $3$. And since the number is not $2$ or $3$, and is divisible by one of them, it can not be prime. Q.E.D.


Why would this answer be voted down?

Question: Two dogmas of empiricism - logical vs analytic truths... is there really a distinction?
Answer: Because it simply does not answer the question as asked. The question asks for an explanation of the reasoning of Quine and the extent of consequences following out of it.
Your answer states some things about logic as if they were angelic gospel and not up to debate - something which Quine points out as being nonsensical - and thereby allegedly rejects Quine.
Doing this without even trying to understand and explain the reasoning in question both means that this is not an answer to the question and would be considered bad conduct in philosophical discourse since it transports a maxim of "I know better, you (or this guy, respectively) know(s) nothing".
Comment: It seems to me that you are not realizing that this question is only focusing on the aspect of Quine's paper that Quine himself already acknowledged is a logical certainty: "No unmarried man is married."
Comment: A direct quote from Quine's paper: >>>(1) No unmarried man is married.
The relevant feature of this example is that it is not merely true as it stands, but remains true under any and all reinterpretations of 'man' and 'married.'<<<

Why would this answer be voted down?


Looking for books specializing in chess play from black

Question: I play online chess at a popular site and while playing from black, I win 58% of my games. I think I have a natural tendency to be a 'counterpuncher'. I seem to derive a perverse enjoyment in playing as the underdog and find it ammusing on some level to be able to survive my opponent's best attack. I'm a 1720 rated player in the 84th percentile of 30k players using E.L.O rating system. I'd like to advance my knowledge from black but can't find much devoted material. I'm guessing my otb play would be 1500-1600.
Comment: after the opening, the differences should be lost. I think studying openings from the view of blacks will do it. I doubt there is such thing as white/black-style (post-opening ofc)
Comment: What is your winning percentage with white? And what is the rating average of your opponents? Generally I believe that at your level the color should not matter much, because most of your opponents would make mistakes in the opening, so that the first move advantage  is not all that relevant.
Answer: It was my pleasure and recognition to see somebody asking to recommend some books how to play with BLACK. They were suggesting 3 books. All of them happened to be mine:

Black is OK! (1988),
Black is still OK!
Black is OK forever!

It shows the good taste of the members... Gratefully I draw your attention to some more. Winning with the Gruenfeld (Batsford, 1986) which could not be a BLACK is OK! book by name, for this "Winning with ..." was a Batsford series. But I assure it qualifies by the content. Finally there is a Sicilian subvariations (1994) which appeared in 5 languages simultaneously. And last there is a 'Rare Openings' book (English, Deutsch, French) which deals with everything but 1.d4, 1.e4, 1.c4 and 1.Nf3. I'm glad to join you and look forward to receive your comments, thoughts, etc.
I'm waiting for your messages too in: email@example.com ADORJÁN András
Comment: Wow, GM Adorján, is it really you? Welcome to the site.
Answer:
Black is OK!
Black is Still OK!
Black is OK Forever!

All books are by András Adorján.
A sample, Black is OK, or the Presumption of Innocence in Chess:

In criminal law, the suspect is entitled to the presumption of innocence until it is proved beyond reasonable doubt that he is guilty. It might help me a lot if I was well-versed in law, but perhaps it would also make my argumentation bloody boring. So what am I getting at is that we should try to take an unbiased approach, and think of the starting position of the chess game. BLACK does NOT have to equalise, as it is not BLACK who has to prove anything in the first place! I presume - in the spirit of the presumption of innocence - that the position is equal. It is White who has to prove that he can get an advantage. And, as he has the right to move first, he sees to it immediately. Naturally, starting the game should not be mistaken for taking the initiative!
Comment: Anyone else should feel free to recommend 'black' books too. I'm on a quest to 1800+ but aren't smart enough to get there naturally. Btw iamlam, I'd give you an up vote but can't yet. I'm too low relyability...
Comment: Some funny observations there @iamlam. Thanks for the link, I'll use it as a starting point for some hopefully novel and inspired chess play! I'll be sure and pick up A. Andorjan's book for my library too.
Comment: Definitely an inspirational rant! :)
Answer: i have a book called winning with the najdorf, it's pretty good, for white and black.
Answer: It's a rather old book, Barnes and Noble or amazon.com may have it. Fred Reinfeld's "Attack and Counter Attack in Chess" has a section entitled: From Black's point of view.
Answer: The books of Victor Korchnoi the archetypal counterpuncher himself -
Chess is my life (1977)
My best games : with Black (2002)
Korchnoi's 400 best games (1978)
And what IGM_AA said.
Answer: I highly recommend The Sniper by Charlie Storey.
The publisher's blurb says:

The Sniper is a dynamic and universal opening weapon for Black which
  can be used against all mainline openings. Black's system of
  development with ...g6 and ...Bg7 initially allows White to occupy the
  centre but, in true hypermodern style, Black strikes back immediately
  with ...c5. The Sniper can lead to original or barely-known positions
  in which Black can strive for the initiative. It's also rich in
  move-order possibilities, with potential transpositions into Sicilian,
  King's Indian or Benko-type positions.

In my opinion the book delivers what it claims.
Comment: After 1 e4 g6 2 d4 bg7 3 nf3 c5 4 dc white is better. Do not play the Sniper.


Why is beta actin commonly used as a control in Western blots?

Question: It is about the western blot question. The paper:http://www.sciencedirect.com/science/article/pii/S1931312813001145.
In the western blot experiment in this paper, they use beta actin as control. And also I saw other research paper also use beta actin as control. So why is beta actin used, not other gene? is it because it expressed in all different kinds of cells?
Comment: Other genes can be and are used. Basically any gene which is expressed constitutively at high levels and is a different size than your protein of interest can be used as a loading control.
Answer: β-actin belongs to a class of genes called housekeeping genes. Their proteins typically perform functions that are required across essentially all cell types (for example, β-actin is part of the cytoskeleton's microfilaments), and are supposed * to be not affected by experimental conditions. In Western blotting, they are run as a "loading control" to show that very similar amounts of protein were loaded in each lane. This is absolutely essential in some experimental systems where it may not be possible to always collect the exact same number of cells for each sample, such as when working with primary cells, tissue samples, or systems where you may be altering protein synthesis, cell size/number, or apoptosis.
There are many different loading controls to choose from, and some may be dictated by the cell/tissue type you are examining — for example, when working with stem cells, you may want to show that your experimental conditions didn't induce differentiation in the cells, so a pluripotency marker like Oct-4A or Sox2 may be chosen. In other cases, you may be examining fractionated lysates (a membrane preparation, just the nuclei, mitochondria, only the soluble fraction, etc.) and so may choose Na/K ATPase, Histone H3, COX IV, or GAPDH, respectively.
The choice of loading control can also be influenced by the size(s) of the protein(s) you are analyzing, as investigators frequently either strip Western blots and reprobe them with the loading control, or run two different species and detect with different colored secondary antibodies when performing fluorescent Westerns. In either case, you want your loading control to be a different size than your original targets.
Finally, all of this is assuming that the researcher has already attempted to load equal amounts of total protein per lane by using any one of a variety of methods for quantitating protein concentration. These include Bradford, Lowry, and BCA type assays, which may or may not be detergent compatible, staining the membrane after transfer with dyes such as Ponceau S, SYPRO Ruby, or India ink, or staining the gel with Coomassie or other proprietary Western-compatible stains.
*In reality, some scientists are becoming more and more aware that many experiments actually do affect a number of "housekeeping" genes, but when most see variations by, for example, Western blot or qPCR, they often choose a different loading control to use.
Comment: Good answer. You might also add total protein as an option for a loading control, e.g. Comassie or Ponceau stains, or a Lowry/Bradford assay; this does not assume anything about a specific protein, but allows expressing the changes of protein X relative to total protein.
Comment: @Roland thanks for the comment. I had kind of assumed that the researcher would already have done a protein assay before loading the sample, but I can make that explicit.
Comment: I meant using total protein instead of housekeeping genes. (In my humble opinion the "housekeeping" gene concept is fundamentally flawed; typically such genes are in the end verified against total protein anyway, so why not use total protein in the first place.)
Answer: Beta-actin control provides assurance that effect you see in protein expression is not due to overall protein synthesis change.
For example, if you study some illness, it might cause change in metabolism, weight loss, loss of ability to synthesize different proteins or absorb amino acids from diet. You have to control for that, and something as universal as actin is one option.


How to change Spotify Facebook login to email login

Question: Is there a way to change my Spotify login from using Facebook to using just email and password?
Comment: I had to [contact](https://www.spotify.com/us/about-us/contact/) Spotify customer support to unlink it from Facebook.
Answer: You can do so by disconnecting from Facebook. The following instruction shows how to do this:

Disconnect from Facebook.
Since you have a dedicated Spotify account, disconnecting from
  Facebook is easy.
In the desktop client:
Windows - Go to Edit > Preferences > Social Network > Disconnect from
  Facebook.
Mac - Go to Spotify > Preferences > Social Network > Disconnect from
  Facebook.  Once you have done that, your Spotify account is no longer
  linked to Facebook, you need not continue any of the steps below.
You may find due to data caching in the client, that you still see
  Facebook information (such as the People list) hanging around, a quick
  clean reinstallation of the application should fix that for you.
If you can't see the option to connect/disconnect, then you are logged
  into a Spotify account created with Facebook not a dedicated Spotify
  one.
https://community.spotify.com/t5/Accounts-and-Subscriptions/Tutorial-How-to-Disconnect-Spotify-from-Facebook/td-p/247266
Comment: This answer only works to disconnect Facebook if you signed up to spotify with your email address and then linked it to your Facebook as a secondary step. The question is actually about 'logging in' to Spotify using Facebook, which means you signed up with Facebook credentials.
Answer: If you signed up to Spotify with Facebook credentials and use your Facebook ID/password to log in to Spotify, then there is no simple way to convert the account.
You need to contact Spotify support.
Only people who signed up to Spotify with their email account and then added Facebook connection as a secondary step can disconnect it in settings.


What is the maximum version of iOS compatible with the 2nd-generation iPod Touch?

Question: I got an iPod Touch 2nd-gen. (Model # MC086LL) and all the fun games I find in the App Store require iOS 4.3. Is it possible for me to upgrade it to 4.3?
Comment: Does this post help isolate the OS versions for your iPod? http://apple.stackexchange.com/questions/55180/which-8gb-ipod-touch-do-not-support-ios-5
Comment: Or this? http://apple.stackexchange.com/questions/9362/can-a-2nd-generation-ipod-touch-be-upgraded-past-2-2-1
Comment: So 4.2.1 is the highest it can be upgraded?
Answer: iOS 4.2.1 (8C148) is the maximum OS version it can be upgraded to so you won't be able to install 4.3 or newer OS using iTunes and Apple supplied versions of the software.
Answer: iOS 4.2.1 is the highest iTunes can install on that model.
You can't get the latest greatest apps but there are tons of vintage apps available, even for models that can only run iOS 4.2.1 or earlier.  The trick is finding them.  This is one way,
https://sites.google.com/site/appleclubfhs/support/advice-and-articles/finding-apps-for-older-devices
Then there is an app to find these vintage apps,
https://itunes.apple.com/us/app/vintapps-3.1.3/id639274910?mt=8&uo=4


How can I get the current screen resolution from the command line on OS X?

Question: How can I get the current display resolution from the command line in OS X?
Answer: system_profiler SPDisplaysDataType | grep Resolution

Comment: On a Macbook pro (10.8.3) this only returns the LCD's max resolution, not the current/selected display resolution.
Comment: On my Air running 10.8.4 with an external display, this shows both the Air's resolution and the external display's resolution, on separate lines.
Comment: It displays the current resolution on a MacBook Pro 2011 model, running Mavericks.
Comment: It shows the current resolution on a MBP with OSX 10.9.4
Comment: For a Retina screen, this shows the physical resolution, not the scaled effective resolution.
Comment: @studgeek I'm not sure if this is still an issue, but on my Air it displays the current resolution. It's very strange the the Pro would alter this behaviour.
Answer: For a quick reading on the current virtual resolution of a single retina display:
$ osascript -e 'tell application "Finder" to get bounds of window of desktop'
0, 0, 2048, 1280

Results for multi-monitor setups vary based on which display is primary and how they are arranged.  Read more here
Comment: This works, the answer provided by Gerry is incorrect.
Comment: Great! This is so much faster than `system_profiler`!
Comment: They give different numbers in case of Retina though.
Comment: This is a better solution, since it returns the "logical" resolution when you're using retina graphics.  If you're using this in a script and need to put the height and width into variables, this might help: ```SCREEN_WIDTH=$(osascript -e 'tell application "Finder" to get bounds of window of desktop' |  tr -d ',' | awk '{print $3}'); SCREEN_HEIGHT=$(osascript -e 'tell application "Finder" to get bounds of window of desktop' |  tr -d ',' | awk '{print $4}')```
Answer: I use the utility screenresolution to get the screen resolution:
$ /usr/local/bin/screenresolution get 2>&1 | grep -oE 'Display 0: [0-9]+' | grep -Eo '[0-9]+$'
1920

Answer: This is a little one-liner I came up to return the the resolution of the main display, that doesn't require any dependencies to be installed on macOS:
system_profiler -json SPDisplaysDataType 2>/dev/null | python -c "import sys,json;d=next(i for i in json.load(sys.stdin)['SPDisplaysDataType'][0]['spdisplays_ndrvs'] if 'spdisplays_main' in i);print d['_spdisplays_pixels']"

If you need to filter based on different criteria, just replace the 'spdisplays_main' in i expression with a more suitable one.
I know someone on the internet will take offence at the fact that this does in fact depend on Python... Python has come bundled with macOS since Jaguar, so even if you're running a Power Macintosh G3 that hasn't been updated in the last 15 years, you won't need to download Python.
Comment: This doesn't work for me, I get `KeyError: 'spdisplays_ndrvs'`.  This is because the first item in `SPDisplaysDataType` is for the integrated graphics card (`kHW_IntelUHDGraphics630Item`), but I'm using the discrete graphics which is the 2nd item in the list.

Also if you're looking for no-dependency solutions, this is a bit more concise and doesn't require python.  Though it might be more obtuse.
```system_profiler -json SPDisplaysDataType | grep _spdisplays_pixels | cut -d '"' -f 4```
Comment: The problem with using grep is that it returns multiple resolutions, use this instead to get the main display `system_profiler -json SPDisplaysDataType 2>/dev/null | jq -r '.. | objects | select(.spdisplays_main) | ._spdisplays_pixels'`
Comment: @EvaLacy I prefer the solution of chris with `grep`because it does not depend on `jq` and I have only one monitor.
Comment: How can I change the command to have a pure python script for the resolution instead of sh?
Answer: I wrote displayplacer, which can help with this. Execute displayplacer list and it will show the current resolution (and more info) for all screens.
$ displayplacer list
Persistent screen id: A46D2F5E-487B-CC69-C588-ECFD519016E5
Contextual screen id: 1124216237
Type: 40 inch external screen
Resolution: 3840x2160
Hertz: 60
Color Depth: 4
Scaling:off
Origin: (0,0) - main display
Rotation: 0
Resolutions for rotation 0:
  mode 0: res:3840x2160 hz:60 color_depth:4 <-- current mode
  mode 1: res:3840x2160 hz:60 color_depth:8
  mode 2: res:3840x2160 hz:30 color_depth:4
...
Persistent screen id: 2960D639-F605-5BB4-A53D-A3263008894C
Contextual screen id: 69733451
Type: MacBook built in screen
Resolution: 1680x1050
Hertz: N/A
Color Depth: 4
Scaling:on
Origin: (-1680,1291)
Rotation: 0 - rotate internal screen example (may crash computer, but will be rotated after rebooting): `displayplacer "id:2960D639-F605-5BB4-A53D-A3263008894C degree:90"`
Resolutions for rotation 0:
  mode 0: res:1440x900 color_depth:4 scaling:on
  mode 1: res:1440x900 color_depth:8 scaling:on
  mode 2: res:720x450 color_depth:4 scaling:on

grep is a simple approach to parse the output.
$ displayplacer list | grep -e Resolution: -e Scaling:
Resolution: 3840x2160
Scaling:off
Resolution: 1680x1050
Scaling:on

Also available via Homebrew brew tap jakehilborn/jakehilborn && brew install displayplacer
Comment: (1) I assume that you're the author of this program (the name being the same).  You should say so, clearly and explicitly, as soon as you mention the program.  (2) This would be a better answer if you actually showed how to parse the output of your program to get what the question asks for, rather than just touting your program. … … … … … … … … … … … … … … Please do not respond in comments; [edit] your answer to make it clearer and more complete.
Comment: displayplacer is great! If you're working on something personal where new dependencies are fine, I really recommend others check this out. I have setup keyboard shortcuts to call out to displayplacer so I can easily change my resolution depending on the task.  It also lets you set display resolutions that aren't possible to choose in the system preferences even if you know about the obscure trick of holding ⌥ while clicking "Scaled".  Not sure why this got downvotes.  It's an amazing util.


In linear regression, is the $R^2$ value enough to assess whether the relationship between the independent and dependent variable is linear?

Question: In linear regression, is the $R^2$ value enough to assess whether the relationship between the independent and dependent variable is linear? It gives the amount of variability in the dependent variable explained by the independent variable. I know that you can plot residuals versus the x value or residuals versus the y value and see if there is a pattern (if there is a pattern then the relationship is not linear). But doesn't the correlation coefficient give enough information about linearity?
Answer: If you look at Anscombe's quartet you can see examples of linear with noise, linear with outliers and non-linear sets of data with the same $r^2$, means and variances.
This image is from the Wikipedia article
Comment: +1 To be contrary or irksome, one might argue that in some sense the last three are all "equally" non-linear, but the contrast with the first one (which is a classic linear scatterplot) speaks volumes.
Answer: Usually not.  The model
$$y_i = \beta + \varepsilon_i,$$
$\varepsilon \sim \text{iid}$, $\mathbb{E}[\varepsilon]=0$ for the relation between $(y_i)$ and $(x_i)$ is perfectly linear, yet has an $r^2$ of zero.
For other examples of what $r^2$ does not say about linearity, see the illustrations in my reply at Is $R^2$ useful or dangerous?.
Linearity is generally assessed by goodness of fit testing; for instance, by including additional terms in a follow-on regression and testing whether they are both significant and important in the application.  One person's nonlinearity is just another person's randomness, so there's no omnibus method.  Nevertheless, usually $r^2$ is just too crude.
Comment: So is looking at a scatterplot fine (or looking at a residual plot)?
Comment: @question Yes, a plot of residual *vs* fit can tell you a lot.
Comment: If there is a pattern in the residuals vs fit plot.....then there is nonlinearity?
Comment: @question If it (a) is a pattern in which the *mean* residual varies and (b) it would be unacceptable to treat that pattern as random, then--practically by definition--there is nonlinearity.  Some patterns do *not* indicate lack of linearity but suggest other phenomena such as heteroscedasticity, outliers, or high-leverage points, so we shouldn't assume *all* deviations from randomness are evidence of nonlinearity.
Answer: In addition to the above answers, a commonly used (in econometrics) test for general regression nonlinearity is Ramsey's RESET test. Suppose you ran your main regression and obtained residuals $\hat\epsilon_i$ and fitted values $\hat y_i$ in it. Then RESET test is the test of the overall significance in an auxiliary regression of $\hat\epsilon_i$ on powers of $\hat y_i$. From regression geometry, we already know that $\hat\epsilon_i$ are orthogonal to the zeroth and the first power of $\hat y_i$, so it makes sense to run it as $\hat\epsilon_i \sim \hat y_i^2 + \hat y_i^3 + \ldots$, in R-like pseudocode. The test is implemented in R as resettest in lmtest package, and in Stata, as estat ovtest after regress.


How to write recommendation documentation?

Question: I was asked to prepare an overview of an existing IT architechture and provide a document that consists of weaknesses analysis and suggestions on how each of the weak spots can be improved.
How to make this document simple to read, not overloaded and specific at the same time? Is there a template I can use for this kind of documentation?
Also, should I provide a description of how a specific segment in the system currently works before I put explanation about what should be changed?
Thank you
Comment: Welcome to Writing.SE! You mention that you are supposed to provide an *overview*: does that mean you are supposed to create a PowerPoint slide or presentation? Or are you otherwise bound to certain tools, such as Word or LaTex? This would be especially important for templates of any kind. Is there a time/word limit? As a first tip: someone in your company might have a styleguide of sorts that you can look up or a sample presentation. If you have a moment please take the [tour] and visit the [help] to learn more about the site. Have fun!
Comment: You said an overview and a weaknesses document - this makes it 2 documents, right? I don't think you need to repeat 1st document inside the 2nd.
Answer: I've done this sort of thing as part of evaluating technologies.  It's usually cast as an evaluation, covering both benefits and weaknesses, rather than just weaknesses.  I suggest getting clarification on whether to address benefits too.
The purpose of such a document is to help people make informed decisions about technologies or designs they don't fully understand.  In my case, the decision-makers were product managers and business people, guided by engineers and other interested people.  Your audience needs to understand the issues well enough to make decisions and doesn't care about the gory details.  They care about impacts, not implementation.
You do something similar, though less formally, when you're considering major purchases.   You probably don't know a lot about how your furnace works, but if you're not getting enough heat and a technician suggests that you could fix that by replacing your heat exchanger, you want to know enough about what that change would mean.  (Maybe you're instead considering just buying some space heaters at a fraction of the capital cost.)  In your case, your readers are people like you, making decisions about systems that they don't know all the details of.  They need enough information to make an informed decision; they don't care about all the nitty-gritty details.
So, all that said, here's a typical structure for such documents in my experience.  (I'm not aware of a specific template that's widely used.)

General overview: a page or less on where you are now and what key factors need to be considered in an evaluation.  Key factors might be things like security, standards compliance, compatibility, and maintainability.  (If you were also evaluating alternate solutions, that would be covered here too.  You don't seem to be asking about this kind of evaluation, sometimes called a trade study, so I'll omit it from the rest of this answer.)

One section per factor.  For each:

Describe the issue: why do we care?
Describe your current architecture; why does this problem exist?
Pros and cons of the current approach (two separate lists).  Unless your problem is very complex, you should be able to cover each entry in a reasonably-sized bullet point.  If you can do it briefly, you can include how you would mitigate cons.
Recommendations: for this issue only, what do you recommend changing?  Or if the current architecture addresses this issue just fine, say that.

Summary and recommendations: you've already made recommendations for each issue; this is where you pull them all together (at a higher level) for your readers.  They need to read the rest, but when they meet with the other stakeholders to make their decision, this last section is what they're going to be working from.

Here's a sketch of an example (omitting the final summary section):

Evaluation of Flux CapacitorTM Architecture
Our Flux Capacitor v. 1.0 has been in production for a year.  Feedback from customers and the industry has generally been positive, but key customers have raised some concerns and we have identified some issues in internal testing that would require architectural changes to address.  These issues include: (list goes here)

Activation Difficulties

The Flux Capacitor 1.0 is activated by engaging the control while traveling at exactly 88 MPH.  (See next section for hardware dependencies and Delorean availability.)  Many of our customers, particularly in the US, have raised concerns about legal and financial consequences.
The Flux Capacitor design depends on a configurable quantum harmonic frequency.  The current value is 88; other possible values include 44, 22, and 176.  Quantum harmonic frequencies are limited by the laws of physics and we can't choose a more convenient value like 65.
Pros:

A speed of 88 MPH is achievable by all vehicular platforms under consideration.  (Footnote: We previously abandoned consideration of low-power conveyances like Segways.)

A speed of 88 MPH is high enough to make accidental engagement very unlikely.  We have had only one report of such an accident, which occurred on the Autobahn.

...

Cons:

88 MPH is above the legal speed limit for most of our customers.  We could mitigate this by speeding up the activation window so that law-enforcement officers are less likely to notice the speeding quickly enough to obtain a license number.

We are having difficulty selling to elderly customers who prefer more moderate speeds.

...

Recommendations: Investigate using a quantum harmonic frequency of 44 MPH and adding safety features to prevent accidental engagement.  This allows our users to comply with local laws and reaches the elderly market.  The change would still allow the unit to fit in most of the platforms currently under consideration; it would not, however, fit in the Miata.  We would need to design and user-test safety controls to prevent negative consequences from a trip down the interstate.  This is a large-scale change requiring approximately $2M in engineering effort.
Answer: In case you are starting from scratch and are free to choose whichever form you like you should have a look at the excellent answer from Monica Cellio.
But: in case you are in an established company there is a good chance that you may not have to come up with your own formatting rules.
Most companies that have done this kind of process a few times will have some sort of styleguides or rules for how to write a recommendation. There are lots of things that may have to be considered:

Which technology is used to present the recommendation?

PowerPoint as a short management summary, maybe in addition to a longer text
Word
LaTex
...

What structure should the recommendation have?

While there are general rules about how this can be done (again, take a look at Monicas answer) a company can choose to go a different path - and if your manager has read a dozen recommendations before, always with the same general layout, then you will want to make it easier for him to find what he is looking for.
There can also be regulatory requirements, depending on which sector your company is in - if it's highly regulated chances are the documentation is supposed to be usable as documentation for adhering to the process in addition to the documenting your recommendation. For example your company may be forced to evaluate at least three different alternatives - in such cases there may be styleguides that are necessary for example for make-or-buy decisions.

How long can and should it be?

A company-wide styleguide will give you recommendations on the preferred length of certain parts. Maybe your exposition can't be longer than one page. Or maybe you need to have at least a page talking about Pro and Con.
By looking at previous examples you can get a feeling for what works and what doesn't work. Does a lengthy documentation equal a good chance to get funding for example?

The most important thing when writing a recommendation is to ask your coworkers whether they know of such styleguides and examples - because your text can be perfect, if it doesn't adhere to the companies guidelines it won't be well received.
The above are some points that you should keep in mind and that you can ask about. Maybe you can't find a complete document, but you found management presentations with summary slides. Take a look at how they are designed and decide whether it might be a good idea to take those as an example. For example are you doing comparisons simply by listing them underneath one another? Or are you putting the Pro on the left side and the Con on the right side? Or do you compare two products like "Product 1 is cheap - Product 2 is expensive" with the next line being "Product 1 offers three of four requested features - Product 2 offers four of four requested features"?
When doing a weakness analysis, does your company prefer a small overview slide/page, followed by one page per weakness and then going to the "recommendations" to talk about strategies for mitigating all weaknesses together? Or does your company prefer to tackle on issue at the time and want you to give the weakness directly followed by specific "recommendations" on how to mitigate the risk?
Finally a lot of "How would I do it?" depends on how much time you have. If it's a documentation that should document what you have done in the last months then people will surely expect you to make a lengthy document with a few short paragraphs in the beginning and end that tell the management what to do and with long descriptions in the middle that will tell your coworkers why you recommended what you recommended. If you don't have much time because this is for example not a high-profile task, maybe just a small project with an even smaller budget, then you may want to keep everything short. The details depend on the exact context, what you can find as a template in your company or get as input from your more experienced coworkers and your target audience.


Converting 'string' to a function/gate in QisKit

Question: I want to give a list of Quantum gates in a .txt file from user an apply them to a Quantum circuit but the gates in notepad .txt file have 'string' type while in Qiskit I need functions/methods. For example:
In .txt file:
'h(0)'
In Qiskit:
qc=QuantumCircuit(2)
qc.h(0)
Which is a method.
What can I do?
Answer: You could try mapping the string input to the function using a dictionary somewhat like what is given here.
So considering that your text file has : h(0) as text, you could declare a dictionary in python as : my_functions = {"h(0)":qc.h(0)} to map string input to function
And in the python script, suppose variable x stores the text h[0] which is retrieved from the text file, to apply the h gate on the quantum circuit, you will just need to do:
my_functions[x]

In a nutshell, the code should be:
qc = QuantumCircuit(2, 2) # makes a quantum circuit with 2 qubits
my_functions = {"h(0)":qc.h(0)} # maps the string input to function call
x = "h(0)"
my_functions[x]  ## this will implement h gate on the first qubit


Best way to notify that a product is out of stock once it's been in the cart for a while?

Question: What would be the best way to notify a client that a product is out of stock after a while? For example, if someone placed a product that is in stock to their cart and just leaves it there without doing checkout, and after a few days the product becomes out of stock. What would be the best way to notify the user of this?
Answer: You should notify the people by displaying the "out of stock" status on the product page as well as inside the cart, since there is where people will head if they want to finish their shopping.
Provide as much information as possible (like when will it be restocked, longer delivery times etc.) and give the user the chance to get a notification as soon as the product will be restocked (for example via E-mail).
You could also display similar products, for example if the user had a black iPhone in his cart and this one is sold out you could recommend him the white one instead.
Why not tell the user before the product is out of stock that there are only a few left? Maybe he will return and finish his shopping, of course this could be very annoying if you are nearly out of stock most of the time, since people won't feel that its a legitimate notification instead just pure marketing.
Answer: I would;
a) (for registered user, or users that have already left e-mail in checkout process) sent e-mail with info on what is out of stock, and offer to finish checkout without that
b) placed info for out of stock on product page
c) placed small notification above the cart icon (usually cart icon is in header)
d) on cart overview / before checkout page, greyed out product, changed its quantity to 0


What's the reason for all of the hedges and walls that I saw when I was in Ireland?

Question: I was in Ireland last month near the northern part of the Republic of Ireland.  100% of all properties were bordered by either a nice hedge or a wall of some form or another.  Even the big fields had a thicket surrounding each one.  Is there a land surveying type of law that establishes this or is the reason for this purely non-legal?
Comment: If you were in the northwest, the stone walls are mainly somewhere to put the stones (and some are [ancient](http://www.museumsofmayo.com/ceide.htm)).
Comment: They are there to keep the sheep in the right field.
Answer: Good fences make good neighbors :) https://www.poets.org/poetsorg/poem/mending-wall
But seriously, hedges were planted to form property boundaries between counties, church lands, private lands, communal grazing lands, etc. A tall, thick hedge obviously and clearly marks a boundary, stops grazing animals from straying, and provides privacy between farms.
Hedges were fairly cheap, could not be carted off like a lumber fence, and required little maintenance. I'm also sure you saw freestone rock walls; same property line function, different effort and effect.
There may have been laws that required property boundaries to be marked by hedges in years past. (Someone with more knowledge of UK laws can respond). But it may simply have been form follows function.
There are current laws that protect hedges from being cut down without good justification, as well as laws that only permit trimming of hedges during certain times of the year to protect the wildlife that inhabit the hedgerows.
Comment: Rock walls have an additional function: a place to put the rocks after you dig them up by plowing the field.
Comment: True; have to put the stones somewhere, and there are lots of them :)
Comment: There is no such thing as "UK law".  Certainly not property law.  NI law usually follows England and Wales (I know very little of Scottish law).  There is no general obligation to fence in England and Wales.  There *is* an obligation to stop domestic animals straying - and that is what the hedges are for.
Comment: @phoog. Walls also prevent the strong Atlantic winds from blowing the topsoil away.
Answer: The farm land hedging could be explained by the GLAS scheme where you get paid €5 for every meter planted for 5 years
http://www.hedging.ie/glas-hedgerow.html


x-rays from dark matter accretion into a supermassive black hole?

Question: I understand that accretion of normal matter into a super-massive black hole leads to x-ray emissions.  Is the same effect expected to occur for dark matter accretion into a supermassive black hole?  Are there any good articles (e.g. on arXiv) I could read to learn more about this?
Comment: Normal matter interacts strongly with EM waves (like X-rays) but dark matter does not (assuming dark matter is the usual WIMP). In principle dark matter could emit X-rays, but you'd have to get it a lot hotter than normal matter.
Comment: In addition to the John's comments, the dark matter is not going to participate in the mechanics of accretion disk formation in the way that ordinary matter does, and the origin of the x-rays lies in the interaction of the disk with itself and with the magnetic field of the whole.
Comment: @dmckee Why does "the dark matter [...] not [...] participate in the mechanics of accretion disk formation in the way that ordinary matter does"?  Won't dark matter be "compressed" when it gets closer to the black hole, and then show similar effects than ordinary matter?
Comment: The accretion disk forms because the infalling dust and gas interacts with itself while still conserving angular momentum about the black hole. Look up Virial heating. The dark matter nearly does not interact, so instead of forming an accretion disk the bits of dark matter just keep orbiting in an unstructured ball. Note that dark matter is not completely non-interacting, so this statement is not absolute.
Comment: Thanks all.  If you write your answers as a formal "answer", I can formally "accept" it.
Answer: Assuming dark matter is a WIMP, NASA made a computer simulation on dark matter particle annihilation to see what would happen when dark matter fell into a black hole. According to the article, it may produce gamma ray as the collisions of dark matter particles increase closer to the black hole.
Here is the preprint for the NASA simulation: http://arxiv.org/abs/1506.06728
And another one: http://arxiv.org/abs/0909.0169
There is, however, some controversy about the validity of these studies. See e.g. this article and this comment and references therein.


how can i get microsoft publisher 97 to work on new Windows 7 computer

Question: My parents use MS Publisher 97 and it will not work with their new computer running Windows 7.  Error message:  Publisher can not start the page wizard design assistant.  Running the compatibility for previous windows versions does not fix the problem.  Really do not want to upgrade Publisher as they are not very computer savvy and a new program would most likely be a huge learning curve.  Any help out there?
Answer: If they have the right version of Win7 you could try the "Virtual XP" option.  See -> http://www.microsoft.com/windows/virtual-pc/download.aspx
If you don't have that version of Win7 you can try VirtualBox or VMWare.  MS Pub 97 will probably work with VirtualBox on Win7 running an XP or Windows 2000 virtual machine.  The guest OS list includes Windows 98 http://www.virtualbox.org/wiki/Guest_OSes but with reduced function (slow).  But slow on a new box might be faster than they're used to on the older box for all I know.
It's not trivial to set up VirtulBox but it's not hard either.  Took me about half an hour to read documentation and install, with most of the time spent reading...  It's free software but supported by a big company (Oracle) so it DOES work for most people.  I assume VMware has similar capability but have not installed/used it myself.  You WILL need a valid licensed copy of Windows to install on the virtual machine, but I assume you have that from the older machine.
PS: I also have some old *.PUB files and I'm going to use this method myself eventually - unless someone else answers with a "converter" program.


unbind excel on super + e keyboard shortcut

Question: I've installed MS Office 2010 using CrossOver, before super + E was bound to open home folder but now when I press super + e its opening MS Excel. How to unbind the MS Excel?
Answer: You can simply rebind the keyboard shortcut to open your home folder. This will automatically disable the other one.
Comment: I already did that on the keyboard shortcut, it didn't do the trick. Its fixed now though, what happened was excel was set as the `default file/folder manager`. I think I accidentally assign it when Im associating the .xlx(s) files to excel.

Thanks for helping out though, anwering silly question ;) I appreciate it.
Comment: You might want to delete or reformulate your question as actually there is no question: Excel was the default file/folder manager, so folders were supposed to open with Excel…


Oversparging grainfather

Question: Most of my beers where I live now have been astringent (5 or so). Some more some less. I found one of the culprits after lots of research: I have incredibly high alkalinity (400ppm CaCO3). So I have decided to mix my own water with destilled water and the usual salts. Now I am worried about oversparging. Presuming I construct ideal water and calculate my mash and sparge water using the usual method, do I still need to worry about oversparging? If so how do I go about avoiding this on the grainfather? I've never read a detailed technique anyway. Keep sampling the sparge runoff every 5 mins and test the pH using a meter?
Answer: Sparging efficiency is, generally speaking, not a factor of water chemistry. By changing your high alkalinity tapwater to distilled water with added salts you should see no difference in sparging efficiency, and the same sparging volume as you used before should work fine without introducing a risk of oversparging.
Using a pH meter on your runoff is also not very useful; it won't tell you anything about when to stop sparging. The tool of choice to determine that is a hydrometer or refractometer. (The latter is easier to use because cooling  down a drop of green wort to the instrument's calibration temperature is much quicker than cooling a tube full of wort.) Test your wort gravity regularly during the sparging process; for an average strength beer you don't want to go below 1.008 in order to prevent oversparging.
Comment: Actually pH does rise as you sparge, and it's increased pH which causes an increased risk of tannin extraction. this point is about pH5.8. One way to decrease this risk is to acidify the sparge liquor down to about the same pH as the mash. The issue here is also not with sparge efficiency, which is only tangentially related to oversparging.
Comment: Thanks for the answer! I wasn't very precise: I know that oversparging has nothing to do with water chemistry. I don't do batches that often and am keen not fix one problem but still have another. All of the strike and sparge water calculations I've seen are just related to vessel volume, grain absorption etc. I've never seen any kind of calculation or formula relating to oversparging. Is there no rule if thumb or is measuring the only way? Refractometer might be easier that hydrometer, but it will still be a pain to get samples with the grainfather.

Oversparging grainfather


Confusion About Min-Cut Probabilities

Question:
Currently going through a video on Counting Minimum Cuts by Tim Roughgarden.
$(A_{i},B_{i}) = \big((A_{1},B_{1}), ..., (A_{t},B_{t})\big) \forall i \in \Bbb{R}$
$P\big((A_{i},B_{i})\big) \geq \frac{1}{\begin{pmatrix} n \\ 2 \end{pmatrix}} = p$, which I interpret as the lower bound on the probability of having at least one minimal cut.
In the problem set that follows two answers A and B are highlighted as being correct. I understand why A is correct; but am puzzled why B is also marked as correct.
A: For every graph $G$ with $n$ nodes and every min cut $(A,B)$ (I am assuming same thing as $(A_{i},B_{i})$) $P\big((A,B)\big) \geq p$.
B There exists a graph $G$ with $n$ nodes and a min cut $(A,B)$ (again assuming same thing as $(A_{i},B_{i})$) of $G$ such that $P\big((A,B)\big) \leq p$.
Answer: I don't understand what you mean by "$(A_i,B_i) = ((A_1,B_1),\ldots,(A_t,B_t))$", an obviously false statement. Perhaps you meant $(A_i,B_i) \in \{(A_1,B_1),\ldots,(A_t,B_t)\}$?
I don't quite understand your interpretation of the statement $P((A_i,B_i)) \geq p := 1/\binom{n}{2}$. Here is the correct interpretation:

For any minimum cut $C$, the probability that Karger's algorithm outputs $C$ is at least $p := 1/\binom{n}{2}$.

This is exactly what A states.
For B, you need to give an example of a graph which satisfies $P(C) \leq 1/\binom{n}{2}$ for all cuts $C$. One such example is a cycle, an example you were probably shown in class.

Confusion About Min-Cut Probabilities


Tourism extension on Business trip

Question: I am travelling to UK on a business trip. My company has provided me a visa letter with dates limited to the conference. I was hoping to stay for 4 days extra so I could tour the place and visit friends. How can I do this? Would the business visa suffice?
Answer: Just say so.
Include your itinerary, such as extra hotels/etc. Optionally in addition to company letter add a letter from yourself saying something like "I wish to stay a few days after the conference and visit local sights/another city/etc".

Tourism extension on Business trip


Transport of newly synthesized proteins to cellular organelles

Question: In the nucleus the DNA is transcribed and processed to mRNA which is translated into proteins in the cytoplasm. What happens between the time a protein is made and that when it reaches the cellular organelle in which it functions? How is it transported to its destination?
Comment: You want to read about transcription and translation. In the nucleus the DNA is transcribed into RNA, which then leaves the nucleus. The processing of the RNA and its translation into proteins happens in the cytosol outside the nucleus.
Comment: RNA processing also occurs inside the nucleus because the introns need to be removed (only exons code for the protein)
Comment: I have changed your title and simplified (and corrected) the content of your question so that it focusses on the question you clearly wish to ask. If I have misunderstood you, please say. A good answer to this question will, in my opinion cover a range of organelles and cellular and sub-cellular locations, as well as perhaps touching on post-translational modifications.
Answer: Mature RNA is translated into proteins by the ribosomes.  Ribosomes bound to the ER (endoplasmic reticulum) translate proteins that are bound for export from the cell.  Free ribosomes, which are found in the cytosol, are used for structures within the the cell (http://www.brighthub.com/science/medical/articles/110037.aspx)
Proteins made on the ER are sent to the Golgi apparatus, and are packaged there for transport out of the cell. (http://www.ncbi.nlm.nih.gov/books/NBK9838/)
As far as I know, the proteins made by free ribosomes remain in the cytosol and are incorperated into certain organelles or pathways upon contact with specific other proteins or signalling molecules.
Comment: Mark can you add some references - we always appreciate that on this site... even for things that are very elementray
Comment: This answer is very limited in scope, as well as being unsupported by references, as Vance writes. I'm down-voting it until you improve it.
Comment: Mark: sort of (on the last point). Maybe worth mentioning https://en.wikipedia.org/wiki/Signal_peptide
Comment: Sorry about that, I updated it with the references.
Answer: Nucleus: DNA transcribed to mRNA.
mRNA is sent out of the nucleus and into the cytoplasm.
Ribosome: Site of translation. Amino acids are placed in accordance with the mRNA codon (triplet of mRNA sequences). Folding is done as the protein is formed.
Once the protein is complete, the golgi apparatus is responsible for packaging and exporting it.
Comment: try adding some external sources to back up your claims - i know it may seem like this is basic knowledge, but it is good practice for others to be able to follow your answer and rationale.
Comment: This is an incomplete answer as the Golgi is only involved in the processing of secreted or membrane proteins.


Remotely Connect to Pi through VNC Outside of LAN Network

Question: I want to be able to remotely access the desktop of my Raspberry Pi 2, running Rasbian Full, from outside of my LAN network. I've been able to easily connect on my network, but I want to be able to access it when I'm not at home too. I am not able to port-forward or doing anything else requiring access to the router options or settings. I've seen some tutorials online but the ones I've found I seem to miss steps from place to place.
Comment: Have you checked out realvnc connect? it's pre-installed on Raspbian, you just need to create a free account.https://www.realvnc.com/en/raspberrypi/
Comment: I have tried that and I got it to work locally, however the icon that other tutorials have mentioned is supposed to be on the task bar doesn't exist for me. I'm not able to connect my pi to my account so I can't connect to it from other computers then.
Answer: You are asking something like "I have a door with a lock but no key". Breaking the lock (using an exploit) I don't see as valid solution. I see mainly two solutions: purchase your own controllable router with internet access or use a reverse tunnel.
For direct connecting to the RasPi you need port forwarding. This can be done with your own router you can manage.
If this isn't an option you can use an encrypted ssh reverse tunnel. For this you need a third device on the internet with a static public ip address that you can connect from the internal RasPi. You can use a second RasPi or much easier you rent a very cheap virtual server on a provider (that's what I have done). Now you can permanently establish the reverse tunnel from the internal RasPi to the external third device. With its known public ip address you can connect from everywhere on the world to it. The reverse tunnel will redirect all traffic to the internal RasPi.


Why MHC class I antigen presentation exist in normal cells?

Question: The book "Kuby Immunology" states that normal infected cells might present antigenic peptides on their surface via MHC class I, but these can't activate naive CD8 cells. Only infected professional antigen presenting cells have the necessary co=stimulatory signals to do so. This is why cross presentation happens.
But then why does the process of antigen presentation on normal infected cells happen then, if it is of no use?
Comment: "This is why" cross presentation happens - is not my understanding. This is why presentation happens, by the professionals (APCs). Your question refers to presentation  by APC in contrast to normal body cells that are not part of the immune system, right? Cross-presentation is a special form of presentation by "antigen presenting cells" - APC. It occurs to me: normal cells present antigen, however may not be called antigen presenting cells. And, please correct: normal cells do not present on MHCII, hence do not cross-present.
Answer: It is of use. They're saying that naive T cells cannot be activated by normal cells because the latter lack the appropriate co-stimulus, namely B7. However, activated CD8+ T cells can recognize antigens presented by normal cells and form a response. This is how cytotoxic T cells are able to eliminate transformed or infected cells.