3 days in Amsterdam: What to see?

Question: In a few days I'm flying to Amsterdam. We will spend there a fun weekend as I repeatedly mentioned in previous questions. But nevertheless a little bit of sightseeing is also necessary. I don't know a lot about Amsterdam, so I'm looking forward for typical sightseeing suggestions. So far, I have only one point on my list, the "Anne Frank Huis".
Comment: If you're like most people then see the prostitutes in their windows and go to a coffee shop that doesn't sell coffee but does sell marijuana... If you're not like most people then add more detail to the question. How different from Anne Frank's house are you still interested in?
Answer: Amsterdam is a relative small city, you can basically tour around for just 1 day.

Van Gogh Museum
Paulus Potterstraat 7, 1071 CX Amsterdam, Netherlands
This 4 storey building contains largest collection from Dutch artist,  Van Gogh.
A pre-recorded guide can be rented for around 10 euros.

Nemo Museum

A science museum. Suitable for children and the young. Ticket is around € 13,50 per person. Opens Tuesday to Sunday from 10 AM to 5 PM. (Closed in Monday)
Reypenaer Cheese Tasting Rooms
Singel 182-Huis | Amsterdam, Amsterdam 1015 AJ
a place where you can taste various Cheese from Netherland
Saint Nicholas Church
Prins Hendrikkade 73, Amsterdam, The Netherlands
The biggest church in Amsterdam.
Nicholas http://stephendanko.com/blog/wp-content/uploads/2010/08/Amsterdam-St-Nicolaaskerk.jpg
Dinner/Winetasting ship tour along the canal

List of tour can be found in The Aviator
Anne Frank Museum

It's actually a small building. The place where Anne Frank wrote her diary during World War 2. The diary is one of the best selling books of all time, placed third just after the Bible and Harry Potter.
Answer: Definitely plan for strolls along the canals, and possibly a canal tour.
Amsterdam has many major art museums, and I recommend visiting at least some of them, even if you're not generally fond of staring at paintings (I'm not). The two most important ones are the Rijksmuseum and the Van Gogh Museum (they are practically next door to each other, on the Museumplein), then possibly Rembrandt's house. Also consider the Hermitage Amsterdam, which shows collections from the Hermitage Museum, rotating every few months. If you're into modern art, don't miss the Stedelijk, normally also on the Museumplein but currently closed with its collections travelling from temporary location to temporary location.
If you're interested in history, apart from Anne Frank's house (whose value is more as a memento than to see unique artifacts or presentations), the major museums are the Amsterdam (history) Museum, the National Maritime Museum (Het Scheepvaartmuseum), and perhaps the Jewish Historical Museum. Also consider the Palace and the major churches and the Portuguese Synagogue (worth at least a quick visit). Somewhat lesser known, but definitely interesting, is the Tropenmuseum, a large ethnological museum (as it is located somewhat off the beaten path, you may not be able to fit it into a three-day visit).
For the young and hip crowd, Amsterdam also has some less conventional places to visit. You can tour the old Heineken brewery just south of the central district. Depending on your tastes, you might visit the Hash, Marihuana and Hemp Museum, the Tattoo Museum, the Torture Museum, the Eroticism Museum, or the Sex Museum.
Given your posting history, I guess you'll want to have dinner in the station/Dam area then head east into the main red light district (worth a visit even if you aren't interested in the wares).
I very strongly recommend getting a museum pass. Partly because you won't have any qualms visiting a minor museum for only half an hour, but most importantly because the major museums can have very long queues, which you can completely bypass if you have free entry. Some museums now allow you to buy tickets online in advance, but not all, and this requires planning. For up to three days in Amsterdam, get the I Amsterdam Card, which includes free transportation on board the trams (and buses and metro) and free entrance to most major and many minor museums. For a longer stay in the Netherlands, get the Museumkaart¹, which grants free entrance to all public museums (which is most of them) in the whole country, and purchase transportation separately. There's also the Holland Pass, which may concievably be worth it in odd circumstances. You can buy the tourist passes (but not the Museumkaart) at the tourist office outside the central station (only until 18:00 on Friday and Saturday, 17:00 otherwise), at the Schiphol airport, in the participating museums (tip: if you're on the Museumplein, the Diamond Museum is just opposite the Rijksmuseum on the Van Gogh Museum side, and there's hardly ever a queue) and other locations.
Depending on your tastes, you'll either mostly travel on foot and in trams, or cycle (there are plenty of bicycle rental places).
Finally, as Amsterdam has many things to offer and you won't have time to see them all, I recommend getting a guidebook on paper (or e-book) and planning your stay.
¹  For some reason, many guidebooks don't mention the Museumkaart, even though it is good value if you're spending more than a week-end in the country. Although the website is in Dutch, the card is not reserved to residents.
Comment: not sure if it's still the case, but the Heineken old brewery used to be available for prearranged tours by groups only.
Comment: Did you get a museum card as a non-resident? It's true that it says nowhere that you cannot get one but it seems designed for residents as it's actually a subscription, automatically extended every year. How does it work at the end of the year?
Comment: @Annoyed The subscription is optional. I've never tried to buy the card online and have it mailed to me, only bought it in person (which carries a €5 surcharge).
Answer: Amsterdam has much to offer. When I lived there, I always took visiting friends on a boat trip through the canals. In about 1 hour you get a nice overview over the city.
You could also consider the "5 hours in Amsterdam question on this forum.
You already found the "Anna frank huis", so I guess you already have some travelguides.
If you are looking for something odd and the weather permits, you could consider renting a bicycle and go to Marken Island. If you exit the city on the Schellingwouderbrug, and you follow the waterside, you have a very nice typical dutch scenery. Also you can experience the sensation of the land being below the waterline.
Answer: It will depend on the time of year obviously but the easiest thing to do is just to rent a bike and bike around.

On saturdays there is a very lovely food market in the northern part of the Jordaan area (called the Noordermarkt).
If you want to go to the van Gogh museum I insist you go early. Same for the Anne Frank (although Anne Frank was disappointing for me). The waiting line becomes VERY long VERY fast.
You may want to skip the vondelpark. It is the biggest park in Amsterdam for sure but it is also very very crowded. I may recommend you to go to the Safati park, which also has a very nice foodmarket next to it.
Beer tasting while getting a cheese platter is a thing here. Here's a list of places I can really recommend: de bekeerde suster (the best), skek, irish pub at marie heineken square, katoen or cafe gollum.
Answer: The above posts cover a lot, but I would also recommend venturing outside of Amsterdam into the countryside - there are some amazing sites to see (like the traditional windmills Holland is known for!) Check out this tour which is my very favourite, but would probably work best if you are going during the warmer months:
Aside from that, a dinner cruise on a canal boat definitely does credit to night time Amsterdam - the canals and bridges are lit up and the spectacle is mesmerizing. Hope you have a great time!
NOTE poster is affiliated with the website linked - it's their website
Comment: Welcome to our site.  As per our [faq], promoting your own website is frowned on without specifically stating your affiliation.  Please do so in future! I've updated your post accordingly.
Comment: such a tour is indeed a good idea, but book locally and check out the different companies offering them (there are several clustered around the central railway station).

3 days in Amsterdam: What to see?


Which is the most well coded and semantically correct naked/blank Wordpress theme (based on Wordpress coding standards)?

Question: I've be using Starkers for a while but I wonder if there are blank/naked themes with better code, files, and folder organization (based on Wordpress coding standards)?
Answer: I used whiteboard and Refuled but i think you can take any blank theme, and do some fine tuning to it in order to turn it to your own blank theme.
For example, remove functions you dont need from the functions.php file, and make sure to reduce any unused CSS rules and to better reset the CSS.
I would also take a look at the HTML structure to see it contains DIVs for content and ULs for navigation as standard coding. Of course, you should also perform HTML and CSS validation (by W3C).
Answer: A new default theme from Automattic is underscore s (https://github.com/Automattic/_s). I've used it with pleasure. It's short on features but super clean. It's core is quite similar to the twenty ten and twelve themes.


How would a side channel attack be carried out in a real life situation?

Question: How would a timing attack against AES be carried out in a real situation? You could not guess the key from the processor's power usage after the plaintext is encrypted, right? And what would you need for this scenario? How long would it take? And if side channel leakage is really such a big deal, why is AES still used for the encryption of classified data?
Answer: In hardware, most of the implementations for AES are constant time. My experience is that the current is generally too far into the noise floor to get any real data out; however, I've attacked my AES implementation and a commercial hardware implementation as well with success.  In any software implementation of AES (or ones that I know), I can HALT the system, and dump the core via JTAG and get the keys.
To do a power attack on system, it helps if you know something about the system, but the math you are looking at on a per transistor basis is
$$I_{f,r} =I_{thn}\ln^2 \left[1+ e^{\left[{\left(\kappa \left(V_g-V_{thn}\right)\right)- \left(V_{s,d}\right)}\right]/\left({2 U_{T}}\right)}  \right]$$
$$I_{f,r} =I_{thp}\ln^2 \left[1+ e^{\left[{\left(\kappa \left(V_b -V_g+V_{thp}\right)\right)- \left(V_{b}-V_{s,d}\right)}\right]/\left({2 U_{T}}\right)}  \right]$$
for the N and P FETs respectively.  This model is called the compact EKV model, and if you push through the Taylor expansion, you'll get the subvt and abovevt currents.  Generally, you will see the nFETs to be stronger than the pFETs, which lets you get a feel for what the bit states of the system are.  Having said that, on 14nm SOI (this process is wonderful), my pFETs and nFETs are identical, except for a difference in threshold mismatch.  If you drive the voltage down to get the systems running in subthreshold and control the clock, you can get a really good picture of the circuits.  Once you know the circuits, you can then get the keys.
I use a Keithley 2000 DMM and Keithley 6485 picoammeter that are controlled through MATLAB and I can pretty much get anything I want out of the little black boxes.  (I also have a copper box to isolate noise)
Answer: Well, for example you could have 'encrypted' data normally being sent from a client to a server and the server had a list of known 'pre-shared-keys' for all its clients.  Then one day someone comes along and sends it a random buffer.  The server goes through its list of keys attempting to decrypt the random buffer to no avail.  Based on the time it took to decrypt, you could determine how many clients the server had been serving.  Decryption is a computationally expensive task, and there's all kind of things you can do with just how much time it took.
Edit: For example, AES-256 takes 14 rounds.  Multiply that by 36 pre-shared keys and an adversary can very accurately detect what you are doing.
Another recent vulnerability was a web app that was using strcmp() to compare a password from a user-supplied buffer... The way strcmp() works is it compares characters one at a time until there's a mismatch in a character.  So the attackers timed the response over many millions of attempts and character-by-character determined the password. The solution here would be to hash the password and compare the hash.
Comment: This question seems to be about AES - the block cipher. What you're referring to is the used scheme of encryption and protocol, which both are quite independent from AES - the block cipher.


Is mandatory binding arbitration enforceable if the contract violation is also a criminal violation

Question: Given a standard contract between companies that include mandatory binding arbitration for any contract disputes:  Is arbitration still mandatory when the contract violation is also a serious criminal violation?
Comment: In what jurisdiction?
Comment: @cpast The companies are U.S. and the contracts inter-state.
Answer: A contract violation (or a tort)_ as between two parties is a separate issue from a criminal violation, even though the same conduct might represent both.
It might be mandatory to use arbitration to settle the civil issue. However, no arbitration decree or contract can compel one party not to report a crime, particularly when failure to report would itself be criminal. Nor can a contract requiring arbitration  to deal with a dispute over a contract bind the authorities from prosecuting a crime, should they believe that there is a crime to be dealt with.
Comment: Am I correct in interpreting that the company would have to be found guilty of the criminal activity to be sued outside of arbitration for damages related to that criminal activity?
Comment: @RobC No. That would be a separate issue, although a criminal conviction might be a significant factor. One can file suit without a conviction but with evidence of why enforcing an arbitration clause would be unjust. But recent US decisions have tended to favor arbitration.


What should be done with duplicate of question that had accepted wrong answer?

Question: My question is quite specific: This 2010 question received a seemingly correct answer, but recently it was noticed that the answer is wrong in the sense that it just links to the paper that doesn't really contain a proof. To the new question an excellent answer was given, which shows that quite likely there's an error in the paper. What should be done about this and by who?
Answer: If the questions are completely duplicate, i.e. an answer to one would be an answer to the other one then one should be close as a duplicate of the other one. The general practice to close the newer one as a duplicate of the older one.
In this case, it seems that the old one has an accepted wrong answer. Note that moderators can merge questions which would redirect the new question to the old one and move all the answers to the new question to the old question.
Ideally the author of the old question should accept the new correct answer but that is up to the author, we cannot enforce that.
I would suggest flagging the new question for moderator attention and then explaining the situation and they can decide if it is really an exact duplicate and if so merge the questions.
Comment: You can add the content to the old question.
Comment: I think that asking a good question is an achievement (that's why it's awarded reputation points on the site), so we should not take it away from the person who asked the second question.
Comment: Yes, I agree that a bounty would have been a good solution, but that's not how it has happened. Also, bounties disappear, so if later someone wants to cite that "as XY noticed", then it's quite hard to refer to some text hidden in a bounty.
Comment: The problem is that the newer question gives more explanations why the two classes seem to differ, so it wouldn't be fair to simply close it as duplicate. It would make more sense to close the old question, but I don't know on what grounds this could be done.
Comment: we don't want duplicate questions, the right thing to do imo was for the op to put a bounty on the original question or edit it, not post a second duplicate question. in short, improve the existing question in place of posting duplicates..


Why is the Boomerang Nebula colder than the CMB?

Question: An earlier answer on temperature mentioned that the temp of the Cosmic Microwave Background (CMB) is $2.4\,{\rm K}$ and the temp of the Boomerang nebula as ${\rm 1\,K}$. How did the nebula cool faster than the CMB?
Comment: The gas is cooled as it expands away from the white dwarf however the CMB will cook it up so can you smell what the rock is cooking. Er... Sorry got carried away anyway drinks on me.
Comment: @pela actually I was hoping to wait for the experts such as yourself to show the calculation for the cooling process (using hypothetical nebula) to illustrate the conversion of kinetic energy of stellar winds into light energy, meanwhile I'm running out of drink.
Comment: @user6760: When you're done drinking, you could make that an anwser :)
Comment: @user6760: Okay, thanks for the encouragement.
Answer: The Boomerang Nebula (or Bow Tie Nebula) is a cloud of gas being expelled from a dying low-mass star, at $164~\mathrm{km}~\mathrm{s}^{-1}$ (cf. Raghvendra Sahai and Lars-Åke Nyman: The Boomerang Nebular: The coldes region of the universe?). In general, when a gas expands, it cools (see extended explanation below). If the gas were optically thin to the CMB — that is, if it were sufficiently dilute that CMB photons could easily penetrate — it would quickly get reheated to the temperature of the CMB, i.e. 2.7 K. However, the Boomerang Nebula is optically thick (dense), so the CMB hasn't yet had the time to heat it. The temperature in its outer parts, however, is higher, and as the nebula expands further, it will eventually (on timescales of, say, 1000s of years) be heated not only by the CMB, but also by the central white dwarf, i.e. the remnant of the star that produced the nebula.
Why does an expanding gas cool?
The usual approach to explain this is to consider a gas in a piston. When the volume is increased, the gas molecules do work on the piston, and hence lose energy, so temperature decreases. However, in the case of the Boomerang Nebula, there are no walls on which the gas can do work.
Cosmologically speaking, the nebula expands rather quickly (it has "only" been expanding for ~1500 yr). Assuming that it doesn't have the time to exchange energy with its surrounding, the expanding is thus adiabatic. For an ideal gas undergoing a reversible adiabatic expansion (or contraction), we know that
$$P V^\gamma = \mathrm{constant},$$
where $P$ and $V$ are the pressure and volume of the gas, respectively, and $\gamma$ is the adiabatic index. For a monoatomic gas, $\gamma = 5/3$, but here there are probably also molecules, so it's probably somewhat higher. At any rate, it's higher than $1$, which is the important thing for us, as we shall see below.
Now the temperature $T$ of the gas can be obtained from the ideal gas law:
$$P V = N k_\mathrm{B} T.$$
Here, $N$ is the total number of particles, and $k_\mathrm{B} = 1.38\times10^{-16}~\mathrm{erg}~\mathrm{K}^{-1}$ is a constant (Boltzmann's, to be specific). Even for non-ideal gasses, this relation is usually a pretty good approximation. Combining these two equations, we see that
$$T V^{\gamma-1} = \mathrm{constant},$$
and since $\gamma \gt 1$, it is evident that if $V$ increases, $T$ must decrease.
Comment: @RobJeffries: Well okay, I think that _a_ (not necessarily "the") definition of optically thin simply means τ ~< 1, so that photons have a "fair", but not necessarily non-vanishing, probability of penetrating. But okay, I'll go with "not optically thick".
Comment: If it were optically thin to the CMB, how would the CMB be able to interact with it at all? I think I get it - do you mean there is an exterior shell that is opaque to the CMB and the interior of this shell has cooled by expansion?
Comment: @RobJeffries: Yes, the Sahai & Nyman paper linked to in my answer proposes a two-shell model, with the outer shell have V = 164 km/s, while the inner shell has 35 km/s. They then assume the outer shell to be sufficiently optically thick in CO(1-0) to shield the inner shell from the CMB. But I'm not sure I understand your concern; if all the gas were optically thin to the CMB, it wouldn't mean that the CMB passed unhindered through. It just means that each single particle would be more or less fully exposed to the CMB.
Comment: Fully exposed, but not interacting with it. That is what optically thin means. Maybe you just mean "not optically thick", implying some optical depth and therefore some interaction. Anyway, your explanation of the paper is clear.
Comment: A quick search reveals that [The Great Soviet Encyclopedia (1979)](http://encyclopedia2.thefreedictionary.com/Optically+thick) agrees with me, but I can't find any other sources, so maybe I should start changing my usage of the term.
Comment: Do not struggle - your meaning is quite clear. that the optical depth is finite but <1.


Looking for books in the same style as Hans Kellerer 2004, Knapsack Problems

Question: I really enjoyed reading Hans Kellerer, David Pisinger, Ulrich Pferschy 2004 book Knapsack Problems. Can anybody recommend books in a similar style, about some other classes of problems / optimisation?
Comment: welcome! can you give us more details on the "style" you like, is it because of the many applications, because of the precise math, since it is a discrete optimization problem, or because it is algorithmic? what is it precisely that you like about the book?
Comment: Yes, I liked all of those things about the book!
Comment: I also liked it because it is mostly easy to follow, but I guess that is subjective.
Comment: Although it is discrete optimisation, I like how the algorithms often rely on linear relaxations of one form or another.
Answer: I waited some time but apparently no easy answer here. Thanks for providing some more hints in the comments to your question. One specialty about the knapsack book is: it is a monograph, that is, written by the same author(s). There are only few other books about a particular combinatorial optimization problem, with theory and algorithmic components, and precise in the mathematics, and the "LPs are used" portion.
A brilliant example is In Pursuit of the Traveling Salesman - Mathematics at the Limits of Computation by Bill Cook.
Often, books are collections, that is, they are edited by a small number of researchers, but the single chapters are written by different people, and thus usually differ in style and presentation; usually, there is not much coherence in terms of cross references among chapters etc.
One example is the area of vehicle routing, with books like The Vehicle Routing Problem by Golden et al., or Vehicle Routing: Problems, Methods, and Applications by Toth and Vigo.


What is the difference between "accelerating a particle to light speed" and "turning on a flashlight"?

Question: According to how we understand the universe it would take an infinite amount of energy to accelerate the ambiguous "particle" to light speed. Yet there are all kinds of reactions that cause light, seemingly without providing the infinite amount of energy needed to accelerate particles to light speed. Burning wood in a campfire or heating tungsten in a vacuum both cause particles that were not traveling at light speed to somehow become traveling at light speed, otherwise both would be totally useless. What am I doing when I light my cigarette that the guys at CERN can't figure out?
Comment: The guys at CERN can light a cigarette easily, like you. But you should try to accelerate a proton beam to 3 TeV to see what issues they had to resolve. There is a big difference between accelerating massive particles (that cannot move at the speed of light) and sending out photons (that are born moving at the speed of light and actually are unable to move with any other speed).
Answer:
Yet there are all kinds of reactions that cause light, seemingly
  without providing the infinite amount of energy needed to accelerate
  particles to light speed.

If you're imagining that there are photons at rest within the flashlight when it's off and the flashlight accelerates photons to light speed when it's turned on, then I can see why you're asking this question.
But that's not the case.  A photon is created when it is emitted by some process, e.g., an electron dropping from a higher energy orbital to a lower energy orbital.
The photon is created at light speed and, in fact, this must be the case for any massless particle.
A massive particle cannot be accelerated to light speed but a massless particle must travel at light speed.
Answer: It takes an infinite amount of energy to accelerate a particle with mass to the speed of light. A photon does not have mass, thus can move at the speed of light. Note that a photon does not accelerate; the moment it is created it moves at the speed of light.
Answer: Photons have no mass, they always travel at the speed of light. Not so for massive particles. You could try building a collider with massless particles, but you would fail for several reasons: The only freely propagating massless particle is the photon, but it does not have a charge, so you cannot bend it to follow a circular collider. You could still build a linear accelerator, though. But then, it is not interacting with itself, since it couples to electric charge only, so there's no point in shooting photons on photons. You could propose to build a fixed target experiment, where you shoot photons on resting particles. This can be done, and is generally called Compton scattering or Photoelectric effect. But your experiment would still be not very interesting, because it's not the speed of the particles, that makes these collision events creating new physics, but the energy they carry. If you want to create new particles, you need to have the energy equivalent to do so:
$$ E^2 = m^2c^4 + \lvert \vec{p} \rvert^2c^2 $$
There is no velocity in here, the velocity does hardly change anyway for highly energetic massive particles. Last but not least, the photons couple only via electromagnetic interaction, while the hadrons that are used in the LHC for example, couple via strong, weak and electromagnetic interaction, so you will have a much richer spectrum using hadrons. There are many more technical reasons why to not use photons (lower cross-section for example).
Comment: Good question. $E=mc^2$ is not the full energy relation. I updated my answer. For a photon, it is simply $E= \lvert \vec{p} \rvert c$.
Comment: There are plenty of points of shooting photons to photons. Of course they need to carry quite a lot of energy. Have a quick google search for "gamma gamma collider" ;)
Comment: I wasn't sure how to ask that question and deleted it so I'm glad you caught it while it was up, thanks.


What are the names of the fingers in classical Latin?

Question: What are the names of the five fingers in classical Latin?
Some fingers may have several names, some may have none; I place no restrictions on the numbers of translations.
Googling gives some answers, but some concern medical Latin and it's not easy to judge the credibility of other sources.
The second link seems promising, but I can't tell whether the names are also classical, as some of the quoted sources are younger.
Answer: The following, taken from a transcription of Smith & Hall's 'Copious & Critical Latin-English Dictionary', should give you everything that you need:

Finger (subs.)-, digitus (also thumb or toe):

the fore finger:

digitus index (as used in pointing), Hor. : Plin.
digitus salutaris (perh. as used in greeting). Suet. Aug. 80

the middle finger:

digitus medius, Plin.: Quint,
(digitus infamis, inmpudicus, as used in obscene gestures, cf. Mart. 6, 70, 5)

the third finger:

digitus minimo proximus, Gell.
digitus medicus, Plin. 10, 12. 54
digitus medicinalis (minimo vicinus), Macr. Sat. 7, U, ad init.

the little finger:

digitus minimus, Hor. : Gell. : Macr.

It even has one or two quite impolite gestures, which we modern folk seem to be perpetuating!
To complete the picture, the thumb is (digitus) pollex, for which Smith's suggests further indicative uses.
Comment: @TomCotton Could this be what he meant? http://latin.packhum.org/loc/978/1/2289/417-422,424-429@1#2289
Comment: @brianpck That's probably the one. I shudder to even look at some of the remedies that he gives!
Comment: Thanks! This is concise, complete, and well sourced answer to a list-like question, and that's a rare find at this site. (I took the liberty to reformat slightly; feel free to re-edit or rollback.)
Comment: @JoonasIlmavirta I took the liberty to reformat quite a bit for easy reference...again feel free to roll-back!
Comment: Now I'm curious to know why the "ring finger" was referred to as the "medicinal finger"!
Comment: @brianpck It's a pity, but Smith's 'Pliny' reference to _digitus medicus_ seems to be wrong.
Answer: The above answer is wonderful, but as a supplement Pomponius Porphyrion (2nd c. AD, or later), a commentator on Horatius (Horace), takes occasion in the following line of the Satires,

Nomentanus ad hoc, qui, siquid forte lateret,
  indice monstraret digito; (2.8.25-26)

...to remark in his commentary:

Hoc ideo, quia certis nominibus singuli digiti appellantur.  Et sunt haec nomina: pollex, index, famosus, medicus, minimus.

I think this is worth including, even though it's not classical, since it's an explicit listing of all the fingers (unlike any other source I have been able to find). It substantially agrees with the words given in Smith & Hall, except for "famosus."


Is it permitted to not get married?

Question: Marrying is not a farz in Islam. What if someone chooses not to get married and keep fasting to control desire?
Answer: Allah said in Quran:

وَمِنْ آيَاتِهِ أَنْ خَلَقَ لَكُم مِّنْ أَنفُسِكُمْ أَزْوَاجًا
  لِّتَسْكُنُوا إِلَيْهَا وَجَعَلَ بَيْنَكُم مَّوَدَّةً وَرَحْمَةً ۚ
  إِنَّ فِي ذَٰلِكَ لَآيَاتٍ لِّقَوْمٍ يَتَفَكَّرُون
"And among His signs is this, that He created for you wives from among
  yourselves, that you may find repose in them, and He has put between
  you affection and mercy. Verily, in that are indeed signs for a people
  who reflect. (21)"

[Quran, Chapter 30, verse 21]
Prophet Muhammad (PBUH) said :

النکاح من سنتی فمن رغب عن سنتی فلیس منی
Marriage is my sunnah and who ever turns away from my sunnah is not
  of me

Nikaah (Marriage) is Prophet (PBUH)'s permanent sunnah. It is a great sin for a person who can marry but don't marry.
Once three Sahaba visited Prophet Muhammad (PBUH), one of them (while sitting there) in absence of Prophet said, "Prophet is innocent, but we are sinner" and then one of them said, "I'll never get marry", When Prophet Muhammad (PBUH) came to know there discussion, He said: "You are no more noble or innocent than me, Yes, you are not, If anyone will try to go farther than me, will be mislead"
And there are some social benefit of marriage, It helps to flourish the muslim ummah, and the children while they grow up, take care of their parents who are now older and can't take care of themselves.
Answer: Many people think Marriage is just a Sunnah (in the sense it is not Wajib). Because of the narration in the Sahihayn which was recorded as:

O young people! Whoever amongst you can afford marriage, let him
  marry. Whoever cannot afford it, let him fast, for it will be a shield
  for him.(al-Bukhaari, 5066; Muslim, 1400)

Fasting reduces the effects that desires have on young people. But, in reality, with respect to fuqahaa' who analyzed it, the obligation of marriage depends on the person you are.
Ibn Qudaamah (may Allaah have mercy on him) said:

With regard to marriage, people are of three types:
1. Some fear that they may fall into haraam things if they do not
  get married. Such a person has to get married, according to the
  majority of fuqaha', because he has to keep himself chaste and protect
  himself against doing haraam things, and the way to do that is getting
  married.
2. For some it is mustahabb. This is the one who feels desire but
  there is no danger of his falling into haraam. It is better for him to
  get married than to devote himself to naafil acts of worship. This is
  the view of ashaab al-ra'y and it is the view of the Sahaabah (may
  Allaah be pleased with them and their deeds).
Ibn Mas'ood said:

If I only had ten days to live and I knew that I
        would die at the end of them, and I had any desire to get married, I
        would get married, for fear of fitnah (temptation).

It was narrated that Sa'eed ibn Jubayr said:

Ibn 'Abbaas said to me: "Have you gotten married?"
I said: "No."
He said: "Get married, for the best of this ummah are the ones with
    the most wives." Narrated by al-Bukhaari (5069)

Ibraaheem ibn Maysarah said: Tawoos said to me:

"Either get married, or I will say to you what 'Umar said to
    Abu'l-Zawaa'id: Nothing is keeping you from getting married except
    impotence or immorality."

3. who have no desire, either because they were not created with
  any desire, such as one who is impotent, or they had desire but it has
  disappeared due to old age, sickness and so on. There are two
  opinions:
(i) It is mustahabb to get married because of the general meaning
  of what we have discussed.
(ii) Remaining single is better for him because he cannot achieve
  the purpose of marriage, and he would be preventing his wife from
  becoming chaste by marrying someone else. And he would be harming her
  by keeping her for himself, and he is exposing himself to obligations
  and duties that perhaps he cannot fulfil, and he is distracting
  himself from seeking knowledge and worship with something that is of
  no benefit to him.

Ibn Qudaamah (may Allaah have mercy on him) said:

The apparent meaning of the words of Ahmad is that there is no
    difference between the one who can afford it and the one who cannot.
    He said: a man should get married and if he can afford to spend he
    should spend, and if he cannot then he should be patient.

This applies to one who is able to get married. As for the one who
  cannot, Allaah says (interpretation of the meaning):

"And let those who find not the financial means for marriage keep
    themselves chaste, until Allaah enriches them of His Bounty" [al-Noor
    24:33]

The best people in Taqwa were Prophets (Peace be upon all of them) and most of them we know have married. We cannot be better than them.
Narrated by Anas bin Maalik (radiyallaahu 'anhu),

He says: "A group of three men came to the houses of the wives of the
  Prophet (sallallahu alaihi wasallam) asking how the Prophet
  (sallallahu alaihi wasallam) worshipped (Allaah), and when they were
  informed about that, they considered their worship insufficient and
  said: 'Where are we compared to the Prophet (sallallahu alaihi
  wasallam) as his past and future sins have been forgiven.' Then one of
  them said: 'I will offer the prayer throughout the night for ever.'
  The other said: 'I will fast throughout the year and will not break my
  fast' The third said: 'I will keep away from women and will never
  marry.' Allaah's Messenger (sallallahu alaihi wasallam) said: 'Are you
  the same people who said so-and so? By Allaah! Indeed I am the one who
  fears Allaah the most amongst you, and the most pious of you; yet I
  fast and break my fast, I pray and I sleep, and I marry women. So he
  who opposes my Sunnah is not from me." Reported by Imaam al-Bukhaaree in
  his Saheeh.

It was narrated that Abu Hurayrah (may Allaah be pleased with him) said:

The Messenger of Allaah (peace and blessings of Allaah be upon him)
  said: "There are three whom Allaah is bound to help: the mujaahid who
  strives (in jihad) for the sake of Allaah, the mukaatib (a slave who
  has made a contract of manumission with his master) who wants to pay
  off his manumission, and a man who gets married, seeking to remain
  chaste." Narrated by al-Tirmidhi (1655), classed as hasan by al-Albaani in Saheeh al-Tirmidhi

Source: Marriage
So, marriage becomes obligatory or recommended or even disliked depending on the type of person you are.
Comment: +1 for pointing out that the ruling can change depending on circumstances.

Is it permitted to not get married?


Analyzing composition of a mineral using SEM

Question: If I have a mineral in which I did a SEM analysis on and got the data (elements and their wt% with  Std. Dev., MDL, atomic % oxide % and k ratio) how would I go about quantifying the sample's composition? I know I would need standards to do so but I not sure how to go about this. Can someone please assist? Thank you!
Answer: You would be lucky if you could identify it with only elemental composition. XRD would be the best method to identify material ( the elemental composition is also needed ). Our lab normally used XRD and XRF , and only went to the SEM when special information was needed.
Comment: I agree on X-ray diffraction to check what you have in your sample before SEM. You get structural data and probably the name of mineral, it's really useful in case you have polymorphs. On the other hand, some SEMs can do electron backscatter diffraction and that helps with structure as well.
Comment: I expect the difference in answers may come from the type of samples to be evaluated. We evaluated mostly corrosion products and related alloys and minerals. basically the SEM /EDS could not do it as well as XRF +XRD , and still the techs would spend time looking in the Fink Index. But I loved the SEM , it was great looking at various layers in a corrosion deposit .
Answer: I have to disagree with with @blacksmith37and @Gabija. Using an SEM is one of the best methods there are to identify minerals.
XRD is only useful if you have a nice single crystal, or if you have the material powdered. If it's a mineral in a rock, then the powder will be a mixture of everything, unless you can separate the mineral out. SEM-EDS analysis (which is what you probably did) gives you the chemical composition of the mineral, which is usually sufficient for identification.
Some cases where it doesn't work:

Polymorphs. Quartz or coesite, calcite or aragonite. They will have the same composition. But ideally you have some prior information on the rock so you know what to expect.
X-ray energy overlap. Some elements overlap in the energies, for example Mo, Pb and S. You will only get one peak for them, making it hard to distinguish. But, usually galena (PbS) and molybdenite (MoS2) look so different, so it shouldn't be too hard. Another example is Ti and Ba. If you analyse a feldspar and you get some Ti, it's most likely to be Ba because that's what goes into feldspar, not Ti.
Light elements. It's not possible to analyse Li and Be so no spodumene or beryl.

Even though there are problems, it's still an excellent way to do it.

I know I would need standards to do so but I not sure how to go about this

Too late for that. Measuring standards is part of the instrument's calibration, and you do that before you analyse your minerals. It might have already been done by the SEM operator - just ask them. Unfortunately, many SEMs have standard-less EDS systems, where it's calibrated once in the factory and that's it. Fortunately, the results you get from such systems are surprisingly good, particularly for simple minerals. The problem is that they normalise the results, so it's hard to know if you have a hydrous mineral or just a bad analysis.

how would I go about quantifying the sample's composition?

You already have everything. Mineral compositions are usually reported in oxide wt%, so you get this information straight off the SEM. Mineral formulas are a bit more tricky. You first need to know which minerals it is, and then you need to know how much oxygens it has. For example, olivine has four oxygens: Mg2SiO4. Then you need to normalise your (atomic%) data to that number of oxygens. Here's a website that explains this very well:
https://serc.carleton.edu/research_education/equilibria/mineralformulaerecalculation.html
And in general, a web search for "calculating mineral formula" results in many sites that have worked out examples on how to do it.
If you have the composition, but you have no idea what mineral it is, there are two websites that can assist you:

http://webmineral.com/ This site lists the composition of each minerals in oxide% and wt%, so you can compare it with your analyses.
https://www.mindat.org/ This site has a search by chemistry. You just type in the elements you have from your analysis and it gives you a list of minerals that have them. Then try to look at the relative proportions of you atomic% to try and figure out which mineral it can be.


Why is the color red so prominent in the promotional materials for "Star Wars: The Last Jedi"?

Question: Why is the color red so prominent in the promotional materials for "Star Wars: The Last Jedi"?
Even the title logo of the movie is in red. First look, posters everything is majorly red. Is there any particular reason for this?
Comment: because red == evil
Comment: Watch the movie and find out.
Comment: According to this [AVClub review](https://www.avclub.com/part-kurosawa-part-wile-e-coyote-the-last-jedi-boldl-1821291545), it might also be a Kurosawa hommage.
Answer:
It's symbolic to a new location, a planet named Crait, featured in the film.

"It's way out there. It's very remote. It's uncharted," says Johnson.
  "It's a mineral planet and so there are mines on it." The director
  (previously best known for Brick and Looper) noted how there are some
  "beautiful design elements and I hope some really unique ones that
  we're able to bring into it." - Rian Johnson EW - April 2017

WARNING: Small Spoilers Ahead

Crait was a small mineral planet located in a remote section of the galaxy. **Covered with a layer of white salt over its red-colored
  soil, the planet once hosted a Rebel Alliance outpost during their
  early rebellion against the tyrannical Galactic Empire. Many years
  later, the uninhabited planet became a haven for Leia Organa's
  Resistance, which resulted in a battle between the Resistance and the
  First Order on the planet surface.
  http://starwars.wikia.com/wiki/Crait**

The Color(s) *may tie back to other Star Wars Saga films.

The idea that surface is "white" and TLJ is the second film in a new trilogy might suggest some parallels or homage with/to Empire Strikes Back and Hoth, despite that it also is in some ways very different to previous Star Wars Saga Films.

The other (red) may have to do with Revenge of the Sith. Revenge of the Sith features an epic battle between Obi-Wan Kenobi and his former apprentice Anakin Skywalker now turned Darth Vader on the lava planet Mustafar. The first teaser poster released seems to convey a callback to this idea with similar aesthetics & with split face between teacher/Uncle (Older) Luke and Kylo Ren with Rey holding up a blue lightsaber. Many speculate the relationship between these three characters could be a juxtaposing of what Revenge of the Sith basically accumulates to, which, philosophically speaking, is how and why Anakin finally falls to the Dark Side. The Prequels, through Anakin's tragedy, purpose the idea that the viewpoint and expectations of the Jedi [in this era] should be questioned and/or realized to be nearly impossible to live up to.
Answer: Red has always been the color of the dark side.
See color of the laser swords, decorations, wardrobe, ...
Use of the color for Crait in my opinion is not so much about the planet, but more about the meaning of the act.


Applicability of derivatives and integrals

Question: Why do derivatives and integrals work? I understand the concept on how to apply them, but what makes it possible for them to be used? why does taking the derivative of volume equal an object's surface area? I want to know more about why the theorems and rules work the way they do, and how can I apply them to my thinking instead of just knowing that it works.
Answer: Integration is simply the sum of small stuffs to form bigger stuffs.

You pile up points in a certain direction, you get a line
You pile up lines in a certain direction , you get a surface
You pile up surfaces in a certain direction, you get a volume.
You pile up the cells to form tissues, tissues to form organs, organs to form a complete system.

Derivative is just the opposite of integration and vice-versa. You derive when you want to break something down into smaller pieces.
This explanation may be in some way naïve but that's the way I've understood calculus all my life.
In addition, I think the way they've both worked successfully in many areas of science is from the careful definition of derivation. Given a function $y = f(x)$

The derivative is the rate at which $y$ changes with respect to the change in $x$. If one notes $\text {The change in }y = \Delta y$ and $\text {The change in }x = \Delta x$, the rate (the derivative of $y$ with respect to $x$) is simple $\cfrac {\Delta y}{\Delta x}$.

To get this rate, it is sufficient to $\text {disturb}$ the variable $x$ by an extremely small value, almost $0$ but yet greater than $0$, the value is $\text {The change in }x = \Delta x$. Then after one computes $f(x+\Delta x)$ but note that even if $\Delta x$ is very small, it is not exactly equal to $0$ i.e. $f(x+\Delta x) \ne y$ but $f(x+\Delta x) = y + \Delta y$ where $\Delta y$ is the disturbance on $y$ or change in variable of $y$.
By computing $ y + \Delta y=f(x+\Delta x) $ and some approximation on large powers of $\Delta x$ and $\Delta y$, one can compute the rate $\cfrac {\Delta y}{\Delta x}$.
With this carefully approximated rate, many areas of Science have grown.
Answer: "why does taking the derivative of volume equal an object's surface area?"
This is best answered in reverse. One calculates the volume of a solid by "summing up"/integrating "thin" slices of volume $A\Delta x$, where $\Delta x$ is the width of a slice and $A$ is the cross-sectional area: $V =\int A dx$. Think of using circular cross-sections to get the volume of a sphere.
I'm going to be intentionally sloppy here since being mathematically precise can sometimes obscure conceptual understanding: "too much mathematical rigor causes rigor mortis".
Recall that differentiation and integration are inverses of one another, right? Well, if you differentiate the formula $V =\int A dx$ you get the answer to your question:
$$\frac{dV}{dx}=\frac{d}{dx} \int A dx =A$$


Random revenge downvote without a reason

Question: I got recently a few downvotes done in a couple of seconds interval... Is it possible, that someone just didn't take my criticism and went through my answers and randomly downvoted some of them? What can do with such suspicion? Can a moderator see who is downvoting?
Comment: I [must have misplaced my keys again](http://meta.stackexchange.com/questions/215379/should-drive-by-down-voting-be-more-effectively-caught/215397#215397), sorry about that.
Comment: Looking at answers I understand there is nothing I can do. Please don't get my question wrong - it is not about the fact being downvoted, but about the suspicion that these downvotes are random "revenge" for some maybe a bit more harsh comments.
Comment: I wouldn't worry or read into it too much, these things happen. If I were to hazard a guess, the first because it's phrased very speculatively, the second because it didn't work for some short time (and it also looks like there were a few other answers covering the same territory).
Comment: Note that Moderators _cannot_ see who voted for whom.
Comment: @3524344 I've learned that from comments bellow. I originally thought that they can see individual votes... that would allow them to address my "problem".
Comment: @PavelHoral: they are cr..., non-constructive people who would not survive in another community. SO is a bit special in this regard. It gives a platform for people to criticize without objective (and hence constructive) comments, and in fact, on Meta it is even for free; no reputation lost! These people will go and downvote _everything_, including severe bugreports.
Comment: If it were more than two in a suspiciously short period of time, you might have cause to flag down a moderator, but any blatant vote fraud is usually caught and reversed automatically.
Comment: get like 2/5ths of a up vote on another answer, get your rep back, and be don with it
Comment: @PavelHoral sure just by posting here I have been downvoted more than 20 points even on posts favorited by almost 50 people. This prove the point. Some downvote occurs immediately not even 1 second after it's been posted. I hope someone will do like plentyoffish and take over Stackoverflow.
Answer: There's not a lot you can do.
People down-vote for all sorts of reasons, and the reputation cost of a down-vote is more than outweighed by the reputation gained from an up-vote. So as long as your answer is still scoring zero or more you're still gaining rep.
If you're sure that your answers are OK then just move on look for something else to answer.
Moderators can't see individual votes so if someone has down-voted one or two of your posts we're not going to be able to spot it. There is an automatic script that will reverse serial down-votes (and serial up-votes too) which runs nightly. We can see if this has been triggered. If you spot something that looks like serial down-voting that hasn't been picked up then flag one of the posts for us to investigate further.
Comment: Well the thing is that it makes me want to delete those answers. I kind of hate the fact they have negative vote count. And of course it makes me a bit angry.
Comment: Accepting this one. I understand that there is nothing I can do. But more importantly there is nothing a moderator can do as well as they don't see who downvoted.
Comment: @Pavel, *"it makes me want to delete those answers"* Don't, if you think they matter and are quite sure they're just retaliation downvotes. (My only negatively scored answer was anonymously downvoted after some Meta discussion, by someone who in their profile claims that people who downvote without commenting are cowards, and who has been trying/failed to game the system on multiple occasions... So, I don't care about *their* opinion. Even more: I feel that answer is right, as it solved the problem for me, and I'm sure it will help someone else one day.)
Comment: -1 to this answer. Reason: If you're sure that your answers are OK then just move on look for something else to answer. -> That is IMHO an impractical advice in a low-volume tag where 2-3 revenge downvotes can hurt the reputation of a good answer, thus the motivation of a valuable contributor, too.
Comment: Note that random revenge downvote can come from a community where the serial downvoter script will not help. There are several people, including me, whom the community downvotes no matter what is posted. I got 15 unexplained downvotes within three weeks on Stack Overflow without the moderators being to catch anything. Now tell me that it is normal. Another practical example is downvoting a valid bugreport that even an SE employee was surprised about. Yet another, I was writing almost the same as another answer, and I got -10, and the person taking my answer partially, I do not know, +15.
Comment: I think Your Common Sense was one of the leaders for getting unexplained revenge community downvotes in a huge amount on daily basis. No wonder he has got upset at times. I have never understood that either. Perhaps these people need a DownvoteOverflow subpage.
Comment: @FinalContest: Maybe th reason you're getting downvoted is because you keep saying you're getting downvoted for no reason.
Comment: Misusing votes, I agree, but I'm just saying it could be a reason, that's all. You don't have to tell me I shouldn't vote like that, 'cause I'm not.
Comment: @FinalContest: This is not the place for that discussion. If you have a problem with my answer on another question, comment on that answer.
Comment: FYI: I never downvoted you.
Comment: @chrisf I see some (6 to be precise) random downvotes one after another, it seems really unusual. Is there anything I could do about it?
Comment: _"f you spot something that looks like serial down-voting that hasn't been picked up then flag one of the posts for us to investigate further."_ -- what would that investigation look like, given that you _"can't see individual votes"_? I am slowly building frustration at the fact that when I try to help by providing feedback, I paint a target on my back. And most revenge downvoters are canny enough to not trigger the only automated script that exists. But as near as I can tell, there aren't any other options for addressing the problem.
Answer: In Redirecting to a different url in apache tomcat, you make a suggestion that you say might work, but that you don't really know for sure, and you don't provide any additional detail.  It is probably more appropriate as a comment.
The other question has an upvoted, accepted answer.  I'd just delete your answer, unless you want to keep the six rep (it has one upvote and two downvotes).
Comment: I don't think it's revenge voting.  I think it got downvoted because it's more appropriate as a comment.
Comment: That still wouldn't make it a good answer.  A good answer contains the solution, in enough detail for the OP or anyone else to implement it, and an explanation of why the solution works.  Part of the problem is that the question isn't really a programming one, and is therefore off-topic, so I closed it.
Comment: About the Tomcat -> that is what we have done on our project and it worked. It might be a comment, however I still don't see that as a reason for downvote. About the other question -> there are few important concepts in the answer and the initial downvote was from OP because I had a typo in it (after I've fixed, he did not remove the downvote). But the reason for this question was about suspected random "revenge" downvoting.
Comment: Just curious - do you moderators see vote authors?
Comment: No.  We can only see voting patterns in the aggregate.
Comment: @PavelHoral Just to weigh in, I have to agree with _@RobertHarvey_ on this one. I usually downvote answers like that and suggest that they be moved to a comment instead. While it may work, it was an untested solution and is more of a suggestion than an answer. It's a little too speculative, with no context for support.
Comment: I don't think you are getting the point here. These answers are old. They were downvoted in 30s after I made a harsh comment (I know I know...). I thought that moderators can check who downvoted.
Comment: And btw. I will move Tomcat answer to the comment section... but from my point of view it contains answer which can be accepted right away if OP would verifies that it works.


Vapor Barrier for Wine Cellar

Question: I am building a wine cellar, we have 3 1/2" of closed foam insulation. One wine cellar company says that I do NOT need a vapor barrier because a double barrier is a recipe for condensation and mold disaster in a few years, the other one says I do need an additional vapor barrier because of the humidity in Texas.
Comment: Is the foam between studs or is it continuous? Is it foamboard or is it sprayed on foam? What are the conditions on the outside of the wine cellar (is it outside or is it contained within another building)?
Answer: Closed-cell foam insulation is a vapor barrier itself. If this closed-cell foam is continuous, then you shouldn't have any issues. If it is just in the cavities between wood studs, then the studs may act as thermal bridges which may result in condensation on the humid side if the studs get cold enough.
Comment: And how is the humidity in a location supposed to affect wine inside a sealed bottle? Maybe I missed something in physics class. I am thinking all you need to worry about is the temperature. The closed cell foam should be fine.
Comment: @ArchonOSX, we're talking about the wine cellar walls, not anything about the wine bottles themselves.
Comment: That is what I figured, and why I up voted your answer. It makes good sense. We have basements around here so we would just build one in the basement.
Answer: wine cellars are special creatures because they have their own temperature and humdity control systems.  its further complicated by the fact that where you are and your local climate change how you build them (in modern homes anyway)
in most homes or buildings, the desire is to keep the cold dry air out and the warm humid air in.  thus the need for the vapour barrier inside the wall (on the warm, humid side of the wall).
however, in a wine cellar, it can sometimes be cold and dry on the inside of the room (compared to the outside conditions).  in a place thats very humid, you can get the exact opposite effect where condensation builds up on the room side of the vapour barrier, which does create problems.
the traditional way to solve this was not to.  the stone walls of the wine cellar didnt care if they got wet.  they were stone.  however, nowadays, we have less stone and more man made materials.
the simplest fix is just encapsulate the foam inside and out with an air barrier (tyvek or typar will both work).  this will let the wall breathe, ensuring the wall, if moist inside, can dry out.  less energy efficient, but the best choice in a climate like texas.  just make sure you install it in the correct orientation.  you want the permeance direction to always be out from the inside of the wall (so it goes one way, usually writing side out, on the outside of the wall, and the other way, writing side in on the inside of the wall)
you should also use cement board and tile or stone, or slats of wood as your interior finish, because the former isn't bothered by humidity and the latter can breathe in order to dry out the inside of the wall.

Vapor Barrier for Wine Cellar


Is it possible to create a URL link to a website on the home screen?

Question: Is it possible to create an icon on my desktop home screen (Android 2.1 Samsung Galaxy) that I can tap to fire up the browser to a specific web site?
Answer: Create it as a bookmark in the Android browser. Then, long-press your home screen and choose the "Bookmark" option. Select the bookmark you made and Voilà!

For newer versions of Android, assuming you're using the Chrome browser:

Go to the URL you want in the browser
Open the menu (three vertical dots) and choose "Add to Home screen"
Confirm the title you want to give the icon and click "Add"

Et Voilà! You now have an icon on your home screen that will open your browser to that URL.
Comment: Why doesnt this work for me? I have android 5.0. Is this feature gone?
Comment: @the_prole: Hardly. Still works for me in Android 7.1.
Answer: I was having a problem with adding bookmarks to the home screen with my new Samsung Galaxy Fame, using Android 4.1.2. The 'Add to home screen' option seemed to have disappeared.
The solution seems to be to use the stock browser (not Chrome).
Create the bookmark.
Long press the new bookmark and select the 'Create Shortcut' option.
This places the bookmark on the home screen.
Answer: I just want to add that the currently updated browsers such as Chrome for Android and Firefox offers exporting any site opened in a tab as a shortcut to home screen. There is now no need to create a bookmark to make a home screen shortcut.

For Chrome, simply open the website, tap Menu button and choose "Add to Home screen".
For Firefox, open the website, tap Menu button, go to Page and choose "Add to Home Screen".


Reg File For Windows XP

Question: Is there any registry file to disable changing time by users in windows xp?
Answer: I don't know a registry setting for this, but in my mind the correct way to do this is to  join the useraccount to Users group and remove it from Administrators or Power Users -groups.
For example at Command prompt (DOS-window) you can do this:
Check useraccount's groups and check group's menbers:
    net user MyUser
    net localgroup Users

Add useraccount to local group:
    net localgroup Users MyUser /add

Remove useraccount from local group
    net localgroup Administrators MyUser /delete

When in Active Directory (=Domain) environment this is a bit more complicated, but the principle is the same.
Answer: You can do this using gpedit.msc(Start > Run). Go to 'Computer Configuration/Windows Settings/Security Settings/Local Policies/Users Rights Assignments'.
In the right-hand window, double click on 'Change the system time'.
Disable it.
This only works when your user is not a local admin. When the computer is part of a domain, it's easier to push a GPO.

Reg File For Windows XP


Adding a belt hole without a leather punch

Question: I don't want to invest in a leather hole punch, so how could I add an extra hole (or some other solution)?
Comment: I'll assume gaining weight isn't the solution you're looking for....
Comment: More than losing weight, believe it or not.
Answer: I used to use a heated nail. Simply, hold it with pliers, and heat its tip up for a minute or so on the stove fire. Keep your belt stretched firmly (you can hold one side of the belt under you foot, and the other side with one of your hand, while the other hand is holding the pliers) and point the nail to the spot you want to make a hole, and push into the belt. It makes a small regular hole very easily.

I see many sources on the web mention the nail with a hammer. No need for a hammer, heated nail held firmly with pliers, can make the hole you want.
Comment: Based on my personal experience, **this** the best answer, its faster, easier, and most cost effective(if you ruin anything it would be only the nail, no drills, no knifes, no scissors)
Comment: This also works if you heat the nails up in the oven if you have an electric stovetop. **400 degrees** for **3-5 minutes** should do the trick. Just place the nails in an oven safe dish or foil boat.
Answer: Use a power drill with a small drill bit the size of the hole you want.  Put a piece of scrap wood under the belt first. After the drill bit penetrates the belt, move the drill up and down to clear out the chaff from the edges of the hole.
(if you don't own a drill, you could go to your local home depot - they often have test drills...be discrete....or...somewhere near you a neighbor probably has one)
Comment: If using a power drill, be aware that the belt might start rotating when you get through it. Keep it properly fastened whilst drilling the extra hole!
Comment: I've used used this technique with and Battery Hand Drill, use a "wood bit" not a metal bit for best results.
Comment: A Forstner bit (sp?) Will give you a clean hole.
Comment: Remember that the faster you go, the cleaner cut you get, in this case. Also, be sure to get a very sharp drill.
Comment: You deserve a cookie for this.
Answer: Careful usage of a sharp pointed knife can easily cut you another hole in your leather belt.
Mark out where you want the new hole, and put the knife at the marker and rotate gently. Soon you'll have your extra hole.
In fact most thingies with a sharp point can be used if you are in a real pinch. I.e. one end of scissors, kitchen knives, screw drivers, or even a key if you are a little persistent! Of course the sharper the better...
Comment: @DangerZone And make sure you're not wearing the belt when trying to create a hole!
I once saw in the news, that a girl got her stomach sliced, because they tried to add a hole to the belt with a kitchen knife **while she was wearing it**.
Answer: A lot of shops will punch one for you.
You could go to a shoe repair shop or a menswear shop and ask if they can punch the hole for you.
Comment: It is lacking the _lifehack_:P
Answer: i used a screwdriver bit in an electric screw driver. worked like a charm :)
Answer: Melted a screw banged it in tongue belt with a hammer holding the screw with garden shears that don't work and done deal......my husband thinks I got the neighbour who is a pro DIY to do it !!!!!!!
Comment: Can you elaborate? I don't understand "melted"
Answer: For many years, I've used the awl point found on many multitools (vis. Leatherman) and multiblade pocket knives.  I just use pressure on the belt's metal tongue to make a mark, then take off the belt and drill through with the awl point by rotating back and forth.  Once it pierces through, a few additional rotation strokes will enlarge the hole enough for the tongue to push through readily, and you're good to go.
Answer: I generally use the pointed end of scissors for punching a hole into my belt.
Once, it manages to pierce to the other end, start rotating it, while simultaneously drilling in; until the hole of desired size(or diameter) is punched in.
If the scissors isn't sharp enough, then using the hack suggested by @Hawk


Is "Read or Die" based on manga?

Question: Both are based off mangas right? Do I have to read the mangas for either series or can I just watch the OVA and animes and not have to read the mangas?
Answer: You can watch any anime and its OVA(s) without reading the manga. However, usually manga do contain extra content that aren't covered in the anime and OVA(s). So while you don't need to read the manga to watch the anime, you can for an extra bit of info/story.
So you could read the manga on top of watching the anime and OVA(s) for Read or Die, but it's not necessary to go through both. It could be fun though.
Comment: This answer is _too_ general, in my opinion. While this is frequently true, there are some franchises for which this just isn't the case, e.g. multiple-media projects like Aratanaru Sekai, where you have to read the manga and LN and watch the anime to really understand what's going on. I don't know what the answer is for the specific case of Read or Die, but it should certainly be possible to provide a more specific answer than this.
Comment: Of course, but no one has given a proper answer as of yet, so this should suffice for the time being.
Comment: Downvoted, this is just far too general. It applies to all adaptations across all of media; it works just as well as an answer to "Do I have to read *The Bridges of Madison County* to understand the movie?" as it does for Read or Die.
Comment: Valid point, however that's the way it is with most stories. Usually the show repeats the manga while not covering the entirety of the manga content. Due to this, most shows conform to this answer, so having a more detailed answer woud only provide the same solution.
Answer: According to Wikipedia:

[The OVA is] based on the Read or Die manga series... [It] is a continuation of the Read or Die storyline, taking place a few years after the events of the manga.
R.O.D the TV is a 26-episode anime TV sequel to the Read or Die OVA

Incidentally, R.O.D. started as light novels and manga published at the same time.
As with all OVAs I've seen, while you may be able to watch them and get some understanding of what's going on without reading the original source material, they are usually short and made on the assumption that people who already like the source will be the audience.  Therefore, they tend to rush through exposition, and even skip over details that they assume the audience is already aware of.  As I remember (it has been a while since I watched) it seems that in the case of the R.O.D. OVA, this meant they had very little explanation of the events that happened a few years before.  So probably you would get more out of it if you went back and read the manga or light novels.
Answer: It should be borne in mind that the Read or Dream manga is not in the
same canon as R.O.D the TV. The sisters meet and adopt each other in a
different way. Hisa has a different history and meets the sisters under
different circumstances.
On the other hand, I'm not aware of any contradictions between the Read
or Die manga and either of the anime series.

Is "Read or Die" based on manga?


How do I apply for H1B Visa?

Question: I wish to start my career in US, I heard I have to apply for H1B Visa. What steps are involved in getting the visa?
Comment: For if it's not obvious in Karlson's answer: **you don't**, only an employer can do that.
Comment: I believe you can only get one through an appropriate US employer who can't find the staff they need domestically. There are tonnes of resources and articles describing the process online, did you try reading some of those? Where did you run into problems? What are you confused about having read those?
Comment: I am currently an employee of a software company. I wish to apply H1 B visa. By Karlson answer I came to know I should be appointed by a US employer, so that I can proceed further.
Answer: You will need to get a job in the US and have employer submit paperwork( Forms I-129 for USCIS and ETA-9035(LCA)) for you to be able to receive an H-1B and then you will need to apply for a visa.  Normally an immigration lawyer is engaged (usually by the employer) that helps through the process.
You can start with USCIS Understanding Requirements Guide and also USCIS H-1B page.
One thing to note that there is a yearly cap on the number of H-1B applications granted, which you can take a look at the USCIS 2015 Cap page for details
Answer: Although there's an accepted answer, I'll add one main point that is missing:
If you are planning to arrive in USA with an approved H1b visa, you can do that provided:

A company has interviewed you and offered you a job before April 1st of the year you intended to start working in US.
The company is willing to sponsor (file) your H1b petition on their own or with the help of attorneys, and submit the application (to be delivered to USCIS on 1st of April).
The company is willing to wait until October 1st of that year for you to start working. (prov)

Its the delay/gap between points 2 and 3 that frustrate many companies to do direct overseas hiring for H1b applicants. Hence, if you already have an H1b visa and the company just has to transfer it, they'll be more than willing to do it, since you can start working on the day your petition is approved.
Comment: I like better your answer here. Also your last remark is absolutely essentially and this point had made me think in the recent past **how likely is really to get a job in the USA (as a European working the UK) since your employer has to wait for 6 months from April to October?** Also keep in mind that the actual interview may have taken place in March or even in February. Here in the UK, if you make an employer wait for more than one month (common notice period for a job) then you will probably lose the next job.

How do I apply for H1B Visa?


Index pages for previous months?

Question: Is there a way on how to find number of index pages for last 2-3 months. If yes, then how??
Please help.
Thanks.
Answer: Please update your question to indicate that you are looking for back-links within a specified period as you've mentioned in your comments.
You can use the link operator on Google to find back links (for example - link:mvark.blogspot.com will show back-links for my blog). In the side bar on Google Search, click on "More Search Tools" & then pick "Past month" or specify Custom Range from the list under the section "Any Time" to see back-links during a specified period.
You can also Google Webmaster Tools to analyze back-links
Answer: The beste way to find out all information about how Google sees your website, how its crawled, indexed etcetera is by using Google Webmaster tools: www.google.com/webmasters/tools/
Comment: Hey BasP, thanks for the reply. However, I am aware about these things. I was actually looking out for a way wherein I can find out the number of back-links for previous months. For e.g. the current month is March-2011, how can I find out the back-links for Jan-2011? Is there any way to find it out?
Answer: Definitely look at Google Webmaster Tools as this will tell you all about your site and how it is indexed. You will be able to see backlinks to your site and how your site appears to Google.
One other interesting way to keep tabs on your indexed pages is using a Google Alert. This won't be able to help you with past pages, but is a way to see new pages as they get indexed. Set up a Google alert for the search:

site:www.yourdomain.com

You will get an email each time a new page on your site is indexed.
Comment: Hey lovefaithswing, thanks for the reply. However, I am aware about these things. I was actually looking out for a way wherein I can find out the number of back-links for previous months. For e.g. the current month is March-2011, how can I find out the back-links for Jan-2011? Is there any way to find it out?
Answer: I really suggest Ahrefs.com as one best tool if you want to check past 2-3 months backlink report.
This tool is one of the awesome link research tool. It provides some link research and link analysis features to paid users but some basic tools on this site are free for webmasters.
This tool provides fresh data all the time as the index refreshes itself every half hour. This tool provides link research options including the following features:
site explorer (Overview, External backlinks, New backlinks, Lost backlinks, Anchors,   Crawled pages, Referring domains, Raw data export)
SERPs Analysis (Position Analysis, Daily Stats, Daily Stats table, History of changes, Ads Analysis),  Reports (Report list, Own domain, Standard report, Report filters, Raw Export report)
Labs (Ahrefs Top, Domain Comparison, Chart Comparison, Batch Analysis).

Index pages for previous months?


where can I buy a new trim for my bath plughole?

Question: My bath plughole needs replacing. I don't need the whole unit for the overflow. The problem is that when I fill the bath, half the water has drained away within 15mins. I think the plug doesn't fit properly. My husband thinks there's a leak around the trim. Both could be true. It's an old bath so probably has the old standard fittings (not metric). What's the least we need to replace? I've bought new plugs but they don't fit properly either. I'm looking for plug + plughole, but will I need to get an old style fitting?
Comment: It may be helpful to post a picture.
Answer: Before you replace it, you may just need to take the fitting off and reseal it.
Every fitting is different, most hold the screen on with a screw and then the fitting itself unscrews from a thread adapter on the drain pipe. Once its off scrape off any old sealant. Make a 'snake' (like you did with clay as a kid) out of plumbers putty and lay that as a ring around the drain fitting. Screw your drain fitting back in and wipe up the excess putty.
How old is old? 10 years? 15? 20? 50? 100?
Pics would help.


What causes the spokes of a Wagon Wheel to "move"(rotate) in the opposite direction of the Wagon Wheel itself?

Question: Is it my mind's eye that is the problem or is this a "artifact" of the film? I would think it was my mind's eye as the medium of film is purely analog and not a digital representation that exists to conform to "what should be" and not in fact what is visually seen.
Answer: This happens when the wheel is observed as an image through a projector or with light shining on it that is periodically blinking. What you are seeing is essentially the additive effects of two periodic functions, the first is the period of the light flicker and the second is the period of the wheel rotation.
So, if the wheel is rotating at a frequency that is evenly divisible by the frequency of the light, then the spokes appear to be standing still. If it is rotating faster, then they are appear to be moving in one direction. If it is rotating slower, then it appears to be moving in the other.
Under household lighting, the light pulses are at 60 Hz. The frame rate of movie cameras is usually 24 Hz.
Comment: This video shows all this in more detail. [https://www.youtube.com/watch?v=1m4evUogKNg]
Comment: This also happens in real life in the sunlight. Your eyes also process visual images with a certain frequency, similar to the camera. When you are looking at a car outside, you can experience the same phenomenon.
Answer: As John and Robin mentioned above, it relates to the superimposition of periodic functions. These functions can be an oscillating light source such as 60HZ AC lighting (power plants deliver electrical energy as oscillations to avoid the increased resistance presented by direct current), an oscillating image capture device such as a video camera, or the neuronal oscillations in your retina and primary visual cortex.
Let's start by going through the example where the "reverse spoke illusion" is caused by the interaction of the rotation and neural oscillation. We can then generalize this to all the forms of this illusion.
You perceive rotational motion when your eye "takes pictures" of a rotating object (we'll use a clockwise-rotating wheel with a single spoke for simplicity) as it moves. If the spokes in each picture are slightly clockwise of the spokes in the last picture, then higher order visual processing areas in your brain infer that the cause of this systematic difference in successive images is the physical rotation of the wheel. You experience this accordingly.
However, your brain only takes these pictures so fast. If the wheel is rotating slowly, the successive images are very similar, and it is easy to infer the clockwise rotation of the wheel from the series of small differences in spoke position. However, as the wheel spins faster and faster, the spokes travel farther and farther between pictures (the rate at which these pictures are taken is relatively fixed.) Because the wheel is rotating, it is a periodic function. Every time the wheel rotates once, it is in the same position it was in before. As the wheel continues to spin faster, the rate at which pictures are taken is exactly the same as the rotational period of the wheel. At this point, each picture will look exactly the same, because the wheel will be in the same position at each picture. The wheel will then appear to be fixed and not moving at all. At other speeds, each picture will be taken when the wheel spoke is slightly behind (counterclockwise of) where it was in the last picture. Since the brain infers motion by the relative distance between pictures, it will take this to mean that the wheel is traveling in the opposite direction!
This effect is multiplied by the number of spokes in the wheel. If the spokes are visually indistinguishable, then this period at which the wheel looks the same is the time it takes the wheel to rotate once divided by the number of spokes. A 5-spoked wheel will only need to spin 1/5th as fast for the same effect to occur.
You can now imagine how this phenomenon would present itself in other contexts with interacting oscillations. In the case of household lighting, the oscillations of the electric current effectively serve as the times at which pictures are taken (although this is a little more complicated because there are three sets of oscillations interacting, since your brain is still only taking pictures at a certain speed.) The same occurs when a digital or film camera takes pictures at a certain frequency.
These articles go into more depth on the scientific research that has been done on this phenomenon: Wikipedia article, a relevant research paper.
These pages are nice because they build a little more intuition for the effects of superimposition and convolution of periodic functions: math page, acoustics as an example.
Let me know if you could use some visual illustrations of the effect.


Script fails randomly due to urllib.error.HTTPError: HTTP Error 302

Question: I have a strange problem i've been trying to 'google-out' for several hours.
I've tried also solutions from similar topics on stack but still wiht no positive result:

How do I set cookies using Python urlopen?
Handling rss redirects with Python/urllib2

So the case is that i want to download whole set of articles form some webpage. Its sub-links with proper content differ with just one number, so I loop for whole range ( 1 to 400 000 ) and write html's to files. Whats importatnt here is this webpage need the cookies to be re-send in order to get to proper url, and after a lecture of  How to use Python to login to a webpage and retrieve cookies for later usage? i have this done.
But some times my script returns error:

response = meth(req, response)
  File "/usr/lib/python3.1/urllib/request.py", line 468, in http_response
     'http', request, response, code, msg, hdrs)
  ....
  File "/usr/lib/python3.1/urllib/request.py", line 553, in http_error_302 self.inf_msg + msg, headers, fp)
urllib.error.HTTPError: HTTP Error 302: The HTTP server returned a redirect error that would lead to an infinite loop.
The last 30x error message was:
Found

This problem is hard to reproduce because script generally works fine but it happens randomly after a few thousands of 'for loops'.
Here is curl ouptut from server:
$ curl -I "http://my.url/"
HTTP/1.1 200 OK
Date: Wed, 17 Oct 2012 10:14:13 GMT
Server: Apache/2.2.15 (Oracle)
X-Powered-By: PHP/5.3.3
Set-Cookie: Kuuxk=ae7s3isu2cEshhijte4nb1clk5; path=/
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Vary: Accept-Encoding
Connection: close
Content-Type: text/html; charset=UTF-8
Some folks suggested to use mechanize or try to catch exception but i have no clue how to do this, others said that error is caused by wrong cookie handling but i tried also to get and send cookies 'manually' using urllib2 and add_header('cookie', cookie) with similar result.
I wonder if my for loop and mabey to short sleep might cause script to fail some times..
Anwyay - any help appreciated.
edit:
In case this might work - how to catch the exception and try ignore it ?
edit:
Solved by simply ignoring this error. No everything goes fine.
I used

    try:
        #here open url
    except any_HTTPError:
        pass

On each time i use url.open instruction.
TO BE CLOSED.
Comment: Then you can answer your own question and accept your answer.
Comment: What do you mean by 'TO BE CLOSED.'?
Answer: Let me suggest another solution:
HTTP status code 302 means Found redirection (See: https://en.wikipedia.org/wiki/HTTP_302).
For example:

HTTP/1.1 302 Found
Location: http://www.iana.org/domains/example/

You can grab the Location header and try fetching this url.
There are 8 redirection status codes (301-308). You can for Location header if 301 <= status code <= 308.


What is the purpose of aliens and time travel in Slaughterhouse-Five?

Question: I think it must have something to do with the subject of free will and how war can mess up one's head. What do you think?
Comment: Aliens and time travel sell?
Answer: It's admittedly been a little while since I read the book, but here are a few thoughts.
First, Billy Pilgrim is coming unglued at this point. Keep in mind that Billy Pilgrim survived a major plane crash, which appears to have caused some degree of brain damage. That being said, we obviously can't take Billy Pilgrim's view of events entirely seriously.
The issue of free will is also a major concern here. The aliens have a very different view of time; rather than viewing events and history as linear and unfolding in potentially unpredictable ways, from their perspective everything has already occurred, in a sense.
Their view of time is analogous to a novel or movie in some ways: you could read it straight through, you could skip around, or you could read it and then revisit the parts you liked best. If a character you like dies in a particular chapter, you can just go back and read the parts where the character's still alive. If you could just go back to the chapters where the character's still alive, does death really have the same meaning? Or does the character just happen to be doing badly in that particular chapter?
Here's another interesting question: if the whole book's already written, do the characters have freewill? If I could predict with 100% certainty what you'll do tomorrow, would that mean that you would have no choice but to do it? Classical formulations of freewill require that, given choices A and B, there actually has to be a logical possibility of choosing either. In other words, even if you actually chose A, you could have chosen B instead. Under that version of freewill, if I knew with absolute certainty in advance that you would choose A, then that would mean that there was no logical possibility of you choosing B (meaning that you'd have no freewill).
In other words, classical freewill depends on the idea that there are actual multiple possible futures.
Note that this is in contrast to soft determinism, which argues that you could have freewill even if it was logically necessary that you choose A. That doesn't really enter the book that I recall, though.


Predefine set of transactions to be added as soon as a private chain is initialised

Question: I need some transactions with predefined data that needs to be added immediately after the genesis block. Apart from actually making those transactions through Geth, is there a way to automate these transactions to be added when I set up the private chain?
Comment: Are there any requirements that can't be addressed with a ceremonial approach to the network launch? What are you trying to accomplish, prevent or prove? What are the constraints and concerns the solution should address and why are they composed that way?
Comment: So it's for a PKI implementation using a private chain and the first block strictly needs to contain 5 specified transactions
Answer: Is it absolutely required to be in the first block? With some modifications to Geth you could theoretically apply the state changes at genesis. This would mean every node that has the genesis file you specified would have the contracts predeployed, similar to what Rob was referring to with Pegasys.
Answer: With a standard Ethereum client and a private chain, or possibly Quorum, you may be able to orchestrate this ceremonially.
Consider a process along these line for experimentation.

Initialize the network with a Genesis block.
Start one node, not mining or verifying.
Deploy genesis contracts. They will not be verified because no node is doing that.
Start a miner/validator.
Confirm the transactions were included in the first block.
Begin adding peer nodes.

Pegasys is Consensys's research arm focused on Enterprise Ethereum. Pantheon is a backward-compatible Ethereum node written in Java. Have a look at this doc for a description of a method for adding contracts to the first block. This might be what you are looking for:
https://docs.pantheon.pegasys.tech/en/latest/Configuring-Pantheon/Contracts-in-Genesis/#predeploying-contracts-in-the-genesis-file
Hope it helps.


How do chess engines "think"?

Question: What I want to know is how engines are programmed to find moves. I'm sure they first calculate the most forcing lines such as captures and checks. But what about subtle, deep positional moves? They seem to find them very quickly as well (Generally speaking. Of course they miss such moves now and then). As in, how are they programmed to look for quiet moves/positional ideas? They can't just brute force every move, since that'd take too long, so there should be some clever way for them to arrive at the best moves really quickly. I'm interested in knowing this because I think it'd help players to think over the board in the real world as well.
Comment: This is an awesome question, I really enjoyed the answers.
Comment: Chess engines look at several million positions per second, so they can in fact look at all them until they get a few moves deep.
Comment: Basically they search ahead with a search algorithm (e.g., minimax) and evaluate the positions using pre-programmed heuristics. Although some recent engines (e.g., AlphaZero) develop their own methods of evaluation through playing themselves.
Comment: To add to the comment of @InertialIgnorance, many machine learning (ML) based engines play against itself (or train with a game database). But, we have no idea how they actually 'think'; they are indeed blackboxes!
Answer: In a general way chess engines use a decision tree. The root of the tree is the current position and has a child node for each position that can be made by making a legal move. Each of these nodes in turn have a child node for the positions that can be reached by making a legal move from them. The engine pushes the tree out to a depth defined by its capabilities and the time it is allowed to "think". Positions that can be reached in more than one way are simply cross referenced so that they will not have to be considered more than once. Once the tree is created the computer uses a set of weighted rules to analyze the final positions in the tree and starts to remove those that are undesirable or that the opponent can prevent it from reaching. The tree is cut down this way until only one move remains and the computer makes that move.
http://www.chess.com/blog/zaifrun has series or articles on creating a chess engine if you want a more in depth look at how they work.
Comment: A ply is a half of a move.   A move in chess is one complete 'set' if you will by white + black.  A ply is half of that, so just one color.
Comment: Nice answer, so when you see depth of 30, does that mean the engine has searched 30 nodes deep?  Also, what does it mean by Ply?
Comment: I am not sure what Ply stands for without doing some more research, I have never been good with acronyms. Rather depth refers to how many nodes deep, each node   would be a half move, or to moves deep might depend on the programmer. However I think that convention would have it be the number of moves deep.
Answer: You're asking a pretty complex question, but it's good to go back to basics.  There are a couple of concepts to consider:
Evaluation
If a (real) player is shown a position and asked "who is winning this game?", how do they go about deciding?  Most likely, they will check a few basic things, such as: material differences, the degree to which pieces have been developed or are positioned "well", doubled / isolated / connected / passed pawns, (controlled) open files, how far up the board the pawns are.
Now, if you had to, you could come up with a systematic way to calculate a position score based on the above.  You could decide, for example, that a pawn is worth 1 point, and that a passed pawn is worth 0.3 points more.  Isolated or doubled pawns might be worth a bit less, etc.  If you add up everything, you get an estimate value for the immediate position at hand.
This is known as evaluation, and basically all chess programs have a way to evaluate positions (ignoring novelty AI chess engines which are typically very weak).

But what about subtle, deep positional moves?

Well, we've only barely scratched the surface of position evaluation.  The actual implementation of an evaluation function could be simplistic, to allow for more positions to be evaluated per second (albeit in a rough fashion), or more complex, leading to less positions evaluated, but with a higher degree of confidence.  It's not unusual for the evaluation function to take into account hundreds or even thousands of separate pieces of information.
Search
I've specifically left out something from the above, which most real players will immediately think about - is there any way to immediately win the game for either side?  Any mates or "hanging" pieces visible?  Although it's easy to trivialise this, it's anything but trivial.
What does it mean for a player to have full confidence in a combination?  In the end, it boils down to having calculated all options.  Real players typically won't do this (except for trivial or very forced mates), most of the time we will only consider a handful of options, and rule out others which seem to be "non-constructive" or obviously leading to a loss.  We often make mistakes during this calculation, e.g. we may realise that a change in move orders makes threats evaporate, etc.  The point is that to be completely sure of a combination, you actually need to calculate all the way to its conclusion, assuming each player will only make the best possible move available to them (this is referred to as "min/max").
Now, given that chess has a much larger search space (this is what "all possible moves in the future" is referred to) than what is feasible for a computer to calculate, compromises need to be made.  Just like humans, computers can decide to disregard entire lines of thought based on certain criteria.  This is known as heuristics.  It's worthwhile noting that while you can only be really sure of a combination if you brute force it, a complex evaluation function can often detect the presence of threats (e.g. we could count forks, skewer opportunities, etc, to guide a search in that direction).
In the end, although computers are extremely fast, it's the heuristics which allow them to calculate so deep.  That said, you may be surprised how deep modern engines calculate fully, typically it's beyond 3 moves, even in quick games.
Conclusion / combining it all
So, to summarise - evaluation functions have a lot of intelligence built into them (i.e. they take into consideration more things than your average human player), heuristics allow the computer to cull lines of thought it decides probably aren't going to end well, and computers are extremely, extremely fast.  Add them up, and they're pretty difficult to beat.
Comment: Just an update: "AI"-based algorithms are in some of the best engines nowadays - AlphaZero, Lela, and Stockfish. With the aid of algorithms from machine learning, Stockfish was able to gain some hundreds extra in ELO when playing against other top engines. These engines also contributed interesting data to chess theory as some were trained with zero information fed in - learning from purely random moves at first, playing itself. AlphaZero was able to arrive at many openings played by super GMs. Also, the heuristics used are often alpha-beta pruning (just for a little more info).
Answer: It is just impossible for computers to look deep enough (25 ply and more) and check every possible move.
What makes is possible is the technique called Alpha-beta pruning which means that computers, similar to humans (but way better) follow only the promising continuations.
They evaluate the positions constantly (based on some precoded rules, valuing material, king safety, activity, pawn structures etc) and look into variations that seem to be leading them towards the best position.
It is still close to magic how they manage to do it efficiently enough to evaluate millions of these positions in a second.
So to summarise- you are correct, they can not look at all the moves if they play strategic chess, but they can very quickly look at decent moves. The problem is still with the very long term plans and horizon to which they can see, but this is being worked on (Rybka analyses much slower, but plays much more positional chess, while Houdini is romantic at it's 'mechanical heart' calculating more moves and playing more aggressively). Even computers have their own styles!
Comment: It is impossible to brute force most positions, but I'll add to your answer that there are 6-piece end tables for all combinations of legal pieces (6 total pieces e.g. 3 white & 3 black or 5 white & 1 black). Engines look up the solved answer to evaluate any position with 6 or fewer pieces. I'm not sure what its criteria are when they have a losing position (maximize number of moves before checkmate? Attempt tricks? Attack, going for a checkmate or for a profitable capture?). People are working on 7-piece tables although I don't know its progress / whether it is feasible to use (too many GB).
Answer: I agree with the answers.
I remember GM Roman Dzindzichashvili talking about it, in one of Roman's labs videos, i don't remember what video it was (if anyone knows the details please edit my answer).
Roman said that the developer of Fritz engine is his friend. So Roman tested Fritz to see how good it was, and the developer told Roman that in order for fritz to make complex decisions (sacrificing materials in exchange for positional advantage for example) they had to change the value of the pieces, like telling the program that a bad bishop is worth 1 point, a bishop on an open diagonal is worth 7 points, knights are worth 5 points in close positions...
I don't know the exact numbers for each piece but that's how it works, and now your engine won't have any problem sacrificing a bad bishop or whatever if you can tell him the value of each piece in each position.
EDIT
See also The Chess Programming Wiki.
Answer: Alpha-beta pruning simply means that if you find a line that turns out badly for you, you stop looking at that candidate move, and instead try others.  It is a type of backward pruning meaning that you'll never miss a good move as a result.  Forward pruning, by contrast, is based more on guesswork.  Futility pruning, late move reductions and razoring are types of forward pruning, and all rely on the programmer's feeling for what type of moves should be considered.  A program that does a lot of forward pruning may miss out on startling sacrifices that lead to mate, but on the other hand, it eliminates a lot of really bad moves, and so can go deeper in looking at the moves it does favour.
Most engines search the first few moves at full depth examining all the possibilities.  If no move fails high (i.e. seems clearly worse than a move you've already considered), you extend the search just a bit more.   In general, you continue exploring each line until you reach a quiescent position (with no checks, captures, mate threats, etc.), and then do your evaluation.  Quiet moves may not be considered when they are deep in the search tree, but once you get to that actual position in the game, the engine looks at all moves, quiet and sharp alike.  You can actually see this in the engine output sometimes, when an engine suddenly favours a move that it hadn't been considering a few moves back.
Engines calculate so quickly that it's not so important for them to consider which move to look at first, but for humans this is a key question.  Jonathan Tisdall takes a stab at answering this in his book, Improve Your Chess Now.  When you are on the attack, he suggests you look at the most violent moves first.  When you are defending, you look at the most difficult lines first.  He also cites positional rules of thumb (eg. centralization, coordination) when deciding which moves to look at first.
Other books that may be relevant are Emmanuel Neimann's Invisible Chess Moves and Charles Hertan's Forcing Chess Moves, both of whom argue for the importance of considering unlikely or surprising moves in sharp positions.  Hertan even talks about developing 'computer eyes' for such tactics.

How do chess engines "think"?