May I not use the users stories in Scrum?

Question: It is more convenient for me to describe requirements in technical terms. So is it possible not to use the users stories in Scrum? Will it be Agile still?
Comment: i think the 'scrumness' of a user stories is that it pushes you towards defining work items in terms of actual finished functionality that the business understands
Comment: Will it be Scrum and will it be Agile are different questions. Scrum doesn't imply agility. Neither it requires using User Stories.
Answer: Of course you may! Scrum doesn't prescribe what concrete representation of requirements you should use. There is no such term as "user story" in Scrum Guide at all. Scrum Guide operate "Product Backlog Item" instead.
Scrum Guide imposes three constraints to well defined (or "refined" in Scrum terminology) PBI:

It should be clear to all Scrum Team members.
It should be well detailed.
It should be possible to implement this PBI within one Sprint.

So, theoretically PBI can be any kind of requirement representation.
Main reason, why User Story is used: it is more customer oriented.
But if you are Product Owner and you have no communication problem with Stakeholders, you may feel free to operate with such kind of requirements representation as you want.
Finally, quote from Scrum Primer:

Product Backlog items are articulated in any way that is clear and
  sustainable. Contrary to popular misunderstanding, the Product Backlog
  does not contain "user stories"; it simply contains items. Those items
  can be expressed as user stories, use cases, or any other requirements
  approach that the group finds useful. But whatever the approach, most
  items should focus on delivering value to customers.

So, if it is okay for your stakeholders, there is no problem even if you will operate "SRS style" requirements (like "system shall..." phrases).
Comment: What does SRS mean?
Comment: @LeDarge [Software Requirements Specification](http://en.wikipedia.org/wiki/Software_requirements_specification). Usually, requirements are described in this document much more formal and with more technical terms, than in User Stories. That why I wrote about "SRS Style".
Answer: Having a user story is kinda central to forming a scrum team.  Technically I would say you are not "doing scrum." It may still be Agile if it works for your team and your customer however...
The decision on whether or not to use user stories should not be based on convenience to you, it should be based on what the team needs to succeed and what needs to be done so that the customer gets a quality product increment at the end of the iteration.
If the team can think out of the box enough (and understand the business value of the work item you document) to solution and build something for a customer in an iteration without a formal user story...then go for it.  If you are writing implementation details for your team and they feel like "code monkeys" then you are defeating the purpose of using Scrum and empowering team to deliver incremental value to a customer.
Comment: User Stories is just a _text format_, it's not central to anything.
Answer: Technically no, according to 1st Agile manifesto principle ["Our highest priority is to satisfy the customer through early and continuous delivery of valuable software."][1], because technical requirements explain only the details of implementation, deployment, maintenance and not the business value they bring to the product.
According to what you're talking about that only technical requirements are needed, it's either a self-explanatory particular task, or these requirements are not pure technical and still contain the explanation of a purpose they serve i.e. business value. Because business value is about the profit the User get from using this Product and this Feature instead of anything else (e.g. User can save/earn money, adore the UI or get a feature set covering his paramount needs, when no other apps can do, etc.).
Interesting question. It's a pity that I didn't see it before - it makes me remember that business value is both functional and technical combined, meanwhile the division of functional requirements vs technical requirements was invented only for convenience and simplicity.
Comment: How you manage tasks and whether your create valuable software are 2 different things. Agile manifesto doesn't put any constraints on how you manage tasks.
Comment: The Question contains nothing about 'task management', only the statement "to describe requirements in technical terms.". I've answered from the point of the profit which the user story brings aside pure technical requirements, which specify it and take place on the level of technical tasks after the decomposition of the high-level requirements to busines and technical ones.
Comment: User Story is a format of describing tasks, so one implies the other. In the end it doesn't matter how you communicated your thoughts (whether you _discussed_ business value or not) - what matters is that you _deliver_ the value. And the quote that you copied says (though it's from Agile manifesto while the question is probably about Scrum, but who knows..) "continuous **delivery** of valuable software"


Mark as Duplicate?

Question: So a new "community wiki" type Q/A has been provided by Mr. Lemon about Imbalanced brackets in Minecraft commands. I believe this applies to a lot of questions on this topic, so I was thinking should we mark all questions on this topic as duplicates of this one?
Comment: Oh you're discussing that question, well I'll add this here as well: I provided the same solution on this question: http://gaming.stackexchange.com/questions/207989/unbalanced-curly-brackets-error-with-this-command-block-code-what-am-i-doing, so if we're marking duplicates, one of these should be marked as a dupe of the other (it doesn't matter which came first, whichever is the better one matters more, but as I'm biased I'll let the community decide that :-)
Comment: @Robotnik I remembered someone having written that before, but I decided to pair it with a good question. Come to think of it, the question you answered *is* a really good one (if you ignore the japanese), so yeah: Community decision time.
Answer: I believe that all questions arising from the 'Unbalanced brackets' error should be closed as dupe of either:

How can I make sure to set the brackets in my data tag correctly?
'Unbalanced Curly Brackets' Error with this command block code, what am I doing wrong?

Both of these questions have quality answers which guide the asker to their answer by explaining:

What the error means
How to find the error
How to fix the error

As the old saying goes, teach a man to fish and you can feed him for a lifetime.
Another option is that the second question is merged into the first question, so that both good answers are found under the same question.

@Brythan says the following:

In order to mark a question as a duplicate, you need to know that the problem with the command is imbalanced brackets. If you've done that, you might as well answer. You have all the needed information.

He has a point - we should be closing questions based on the question not the answer. However, that is not applicable to this situation - you already know that the problem is something to do with unbalanced brackets, because Minecraft tells you so: (command taken from this question)
<code>/summon Villager ~ ~ ~ {Profession:3,Career:2,Offers:{Recipes:[{buy:{id:minecraft:diamond,Count:6b}},sell:{id:minecraft:diamond_hoe,tag:{ench:[{id:16s,lvl:10s}]}]}}
</code>

If the question does not give us the error message thrown when they run the command, then it should be closed as Unclear what you're asking.
Comment: Caveat to the last sentence: *Unless it's blatantly obvious what's causing the issue.* :-)
Comment: I would suggest closing as dupe to http://gaming.stackexchange.com/q/265668/ instead of the second option presented, since it's the more general question.
Comment: @MBraedley That's what I originally thought, but then I thought that we could merge the two questions so that we get the generalized question with both great answers
Comment: Ah yes, the good ol' saying: "Give a man a hamburger and he will live another day. Teach a man to hamburger and he will live forever!"
Answer: This seems overly narrow.  In order to mark a question as a duplicate, you need to know that the problem with the command is imbalanced brackets.  If you've done that, you might as well answer.  You have all the needed information.
Closing as a duplicate without establishing that it is a duplicate would encourage other people to close similar questions as duplicates.  Possibly incorrectly.  It's mildly annoying to see a question with the same problem as many solved questions.  It's really annoying to be told that no one can answer your question because of some other question that doesn't solve your problem.
It would make more sense to close Minecraft command troubleshooting questions as duplicates of a general troubleshooting question.
It would make even more sense to close Minecraft command troubleshooting questions as off-topic.  Then we could point people to questions that help with troubleshooting.
Or just allow them.  Don't want to answer them?  Don't.  Let someone else farm rep with them.
Comment: @Timelord I disagree - if the brackets are imbalanced, it will output an error telling you so, which *should* be included in the question. If the question doesn't include the error message, it should probably be closed as unclear.
Comment: @Brythan if you want Minecraft troubleshooting questions off-topic, please feel free to make another meta discussion.
Comment: You make a very good point. We wouldn't know if these questions were duplicates without looking at the answer. We do not take the answer into consideration when VTCing in any other situation I've seen.

Mark as Duplicate?


Microsoft Lumia 540 - unable to find images received via bluetooth

Question: I use Microsoft Lumia 540. I received nearly 450 image files over bluetooth last day. Unfortunately, I am not able to see any of them in my phone now. Checked Photos->Saved pictures, downloads etc. When 'Storage sense' app is checked, I see 1.6GB used space for 'Others' folder. But, couldn't find anything inside it. Connected the phone to laptop. The other folder is not even listed. Please advice.
Comment: Not sure but have a look in File Explorer if you are on Windows Mobile 10. Maybe you can find it there.
Comment: images received will go to sd card-> pictures-> SAVED pICTURES
Comment: I discovered that windows phone8 prompts you to save a file transferred to it via Bluetooth otherwise the file will be missing after transfer is completed
Answer:
Open Storage Sense.
Check the default save location of Photos.
If it is phone go to, Phone->Pictures->Saved Pictures or Phone->Downloads.
If it is in SDcard check the Saved Pictures and Downloads folder in SDcard.
If you canot see it, connect your phone to PC and look in the same folders.

Note : Use the Files app or the built-in File explorer(in case of windows 10) to navigate. Some 3rd party apps may not show all files.

Connected the phone to laptop. The other folder is not even listed.

The other section mentions the filetype that are not yet anslysed or recoganised by windows mobile. It does not correpond to a folder. There is no others folder. All recieved contents are stored in Saved pictures or Downloads.


How can I mount an encrypted disk image so that it is read-write?

Question: I have created an encrypted disk image containing a folder whose contents that I want to keep secure, using the disk utility app. I am able to mount this either by clicking on the image or by using the command line, however in either case, the mounted drive is read-only. I have tried various options including adding the -o read-write option to the command line mount command, however nothing seems to work. I am running under OS X 10.14.5.
Answer: When the Disk Image is created is the time to decide if the image will be compressed (default) read/write or other options. The option you should have now is to Disk Utility:Images:Convert and choose the image you want to be read/write and choose Convert
Comment: Sigh - I must be going mad - I can't think of any other reason how I missed this option :-( Thanks in any case- it's all working fine now!


What items could help against fighting a dragon?

Question: Getting ready to battle a horde of dragons. What are the best magic weapons to fight dragons? Found arrows and some charms against dragon breath. What non-homebrew items could help?
Comment: Are you asking for items specifically tailored to help against dragons, or any items in general that work? The latter is likely too broad of a question. Similarly, would you consider magic items that simply deal a large amount of damage "helpful against a dragon" or do you want items that are, again, specifically effective against dragons despite the likely existence of flatly stroner magic items with no special effects against dragons?
Comment: The headline asks for items in general, but the body asks for "magic weapons" specifically. Are you just looking for magic weapons? Also, do you know the number, types and ages (young, adult, etc.) of the dragons you'll be facing?
Answer: Generally, a Dragon Slayer sword and Dragon Scale Mail.
A Dragon Slayer gives a significant damage boost (3d6) against dragons, while Dragon Scale Mail gives advantage on saves vs breath weapons and Dragon Fear.  If it's the right color, Dragon Scale Mail can also give resistance against the dragon's breath.
If you know the dragons' color[s], there are some other items that can give a large advantage.
If you're fighting a red, gold, or brass dragon, for example, Efreeti Chain will grant you immunity to its breath weapon and any other fire abilities it has.
If it's a green dragon, a Periapt of Proof against Poison will make you immune to its poison breath and bite.
If it's white or silver, Boots of the Winterlands or a Ring of Warmth will grant resistance to its breath.
And an appropriate Ring or Armor of Resistance will help against any dragon with elemental abilities of that type, if you know what you're facing in advance.
Comment: There's always also the [Armor of Invulnerability](https://www.dndbeyond.com/magic-items/armor-of-invulnerability) if you wanted to mention that option
Answer: The Dragon Slayer sword
A rare magic sword ("any sword") from the DMG, p. 116:

You gain a +1 bonus to attack and damage rolls made with this magic weapon. When you hit a dragon with this weapon, the dragon takes an extra 3d6 damage of the weapon's type. For the purpose of this weapon, "dragon" refers to any creature with the dragon type, including dragon turtles and wyverns.


Using client certificates for website authentication

Question: I was wondering if there currently exists a Content Management System that supports PKI and client certificates for website authentication instead of username/passwords. If not, what's a good place to start on developing a site that uses this authentication scheme? Is it possible with Python and Django?
Comment: There might be.  What has your research shown?
Comment: From my experience, the only sites I've come across that used client certificates for authentication were the websites of Certificate Authorities. I'm guessing the average user will face a usability problem with a client cert. It's drastically different from what they are use to: usernames and passwords. Plus, client certs can be stolen from the browser via attacks like XSS.
Comment: Content Management Systems are used in places other than the public Internet.  PKI authentication is used on corporate networks; in some the only thing a username/password will get you is a domain login to your workstation, everything else (including SSH access to administer cloud resources) requires the employee's client cert.  MUCH more convenient than having dozens of passwords for dozens of enterprise applications.
Answer: A simple Google search on "django client certificate" reveals this, and this, and this, which all answer to your question as: yes, Django can work with certificate-based client authentication.
People don't do that often in practice, because client certificates work only if you can arrange for clients to have certificates, basically meaning that you must manage your own PKI. Software for running your own PKI is available (e.g. EJBCA), but PKI management requires strict adherence to clearly defined procedures, which will take you time; the long-term cost of a custom PKI is very often underestimated (that is, if you want to do it properly).
Client certificates will also inconvenience users, because they won't easily (or at all) transfer their certificates to their tablet or smartphone or even alternate laptop, the way they do with passwords. None of this is really blocking, but it explains the rarity of client certificate deployment.
Comment: They are however an excellent way to secure administrative user access.


Does YubiKey with LastPass influence encryption?

Question: I am using LastPass together with a YubiKey Neo. If someone got ahold of my master password (e.g. keylogger), and a copy of my encrypted password vault, would they be able to decrypt it? Or does the YubiKey setup add another layer to that encryption?
Answer: With LastPass, YubiKey is only used for authentication purposes to be able to download your vault and/or login to your LastPass account on their servers.  YubiKey is not however used for encryption purposes, so the use of 2FA with LastPass (or YubiKey) does not influence the encryption of the vault.  It just makes it harder to potentially compromise your account by logging in as you, so 2FA should be enabled as a best practice.
The LastPass database itself is encrypted locally using AES-256 with your master password as a factor to generate a PBKDF2-SHA256 hashed key.  That key, stored locally (not your master password) with symmetric AES-256 encryption is your master password. But, essentially,  your master password is this key and could be used to decrypt files locally -- so if someone copies your local lastpass vault and has the master password, regardless of YubiKey, it could be compromised.
References:
https://lastpass.com/support.php?cmd=showfaq&id=6926
https://lastpass.com/whylastpass_technology.php
Answer: Two factor authentication with Last Pass is only applicable to logging into the service or operation within the application itself. If somebody has a copy of your encrypted database, then only the password itself is relevant.
Yubikey's proprietary "touch to authenticate with a string of characters" method uses a key id and incrementing counter which is not useful for encrypting data.


Bond ADSL+ line with Cable Modem line in one single router

Question: I need two bond ADSL+ modem with cable modem router at the office so I don't have to switch the line everytime one of them is offline, is there any software/hardware that allows me to bond two physical conections into one at my router, so everyone at the LAN is getting the two of em without having to reconfigure everything?
Answer: I am assuming the two links are from different ISPs.
You need a router with at least three interface (one for your LAN, one for each of your WAN connections).  Cisco has a feature called Optimized Edge Routing, which lets the router test each path and then choose the one with the best performance.  So it will automatically switch if one path goes down. Other manufacturers have similar features.
You don't "bond" the two links, because that will cause out of order packets and reduce your performance.  You will use one or the other link, depending on the performance of each.
I am assuming the two links are from different ISPs.
Comment: Exactly, they are both from different ISPs, so im gonna search for those Cisco OER enabled routers, thanks buddy!


Oracle Migration Workbench

Question: Does anybody know anything about using Migration Workbench to migrate db2 database to oracle 10G? I am getting a strange SQL1402N error when I try to get source capture.
Answer: It seems there is some kind of problem with the user you are trying to connect with.
According to the message reference for SQL1402N:

SQL1402N
  Unable to authenticate user due to unexpected system error.
  Explanation:
Call your system administrator. On unix-based systems, the file db2ckpw may not have the correct permission bits set, or the system may have run out of swap/paging space. On Windows NT, the DB2 security service may not have been started or the account may be locked.
The command can not be processed.
Federated system users: this situation can also be detected by the data source.
  User response:
On unix-based systems, have the system administrator ensure the correct access permissions are set for db2ckpw, and that there is enough swap/paging space allocated. On Windows NT, have the system administrator verify that the DB2 security service is installed and started. If the service is running then ensure that the account is not locked.

Oracle Migration Workbench


Fallout 4 - The Molecular Level - Change Faction

Question: So I asked the Railroad first to help me build the relay, thinking I was going to be able to ask for help from all three factions. I would've chosen the Minutemen had I known there was only one faction I could ask for help. My question is this: I haven't gone through the relay yet (in an hours-old save), but have built it with the Railroad's help. Can I reject their assistance and change who I want to help me? The answer is likely, "no," as I've already built the relay, but I'd really prefer the Minutemen over the Railroad as they are the most noble of the factions in my estimation.
Comment: I've gone through the Molecular Level quest, and while I haven't completely beaten the game, I'm fairly certain that who you chose to help build the relay doesn't matter. Without trying to spoil much, you _will_ only use the relay once anyway.. So, while I'm fairly sure it won't matter in the end, I'm not certain enough to post this as an actual answer.
Answer: I can confirm what Unknown Zombie stated in his comment. It does not matter in terms of who you want to ally with for the end of the game.
I can confirm this because I chose the Brotherhood to assist me, and sided with the Institute to get their ending for my first playthrough. And did the opposite on my second playthrough. Neither side really so much as mentioned the fact that I chose their enemy to assist the relay build. It serves no function after that mission anyway.
Comment: It's an OCD thing. I just want the Minutemen to come out on top, to be the heroes. If I side with the Railroad, as I've already done, then they are the heroes. I suppose it doesn't matter much. I'll just play through, then playthrough again. Thanks for the responses.
Comment: Actually you can continue doing quests for the Minutemen and still complete the game with them - they're always available to complete the game with even if you mess up with all of the other factions.


3D character modeling tool

Question: I am working on building a Strategy Game (it will be in 2.5D), and for graphic design part we are using Illustrator and Photoshop for designing (including designing characters). Now we want to start building 3D modeling for characters to simplify the animation process. It seems photoshop does not support 3D modeling, so what tool would you recommend in this case?
Answer: I have been modeling 3D characters for many years, and the best tool I can recommend to anyone, beginner or not is actually a free opensource program called Blender.
It has many useful features and is easy and quick to learn, but the best part is the amount of keyboard shortcuts it has as standard to really speed up development time. You can create your mesh, animate it, texture it and map it in many, many ways just using the one program. It also has its own game engine that uses Python script, but you don't need that for model creation, and the best part is that it's free!
I have used such tools as Maya, 3DS Max, Bryce and ZBrush. Where they all are great tools, Blender is the easiest and quickest. You can get professional standard models no problem from Blender.
As a side though, ZBrush is also a great tool, it has many unique features of its own that none others do, like the ability to literally draw your 3D mesh, (it's especially great if you have a wacom tablet or similar) but it's a bit harder to master.
I'd recommend building your mesh in Blender, then (if you can afford it) use the texturing tools in 3DS Max or Maya as they have some really amazing texture and mapping tools.
But for free, Go with Blender to start with.
Comment: There's nothing easy about blender. Mudbox comes pretty close to functinality of zbrush but is less wacky in how it works.
Comment: Blender is heavily promoted by FOSS fans, but its hard to use. If you really need MAX or Maya to do texturing then you might as well use their superior modeling tools too.
Answer: I have used Cinema 4D alot and I love it. Works like a charm. For me, It was extremely easy to get the hang of it and use it properly.
Comment: Hi there! Could you maybe add some info on why Cinema 4D could be a good tool? We try to have as much detail as possible in the answers :)
Answer: If you don't plan to become a 3D expert, you can quickly design stunning characters with the free software DAZ3D.
You will have for free a very versatile human model that you can morph to your needs (male/female, tall/short, etc...).
You also have access to a lot of ready to buy costumes or props in case you don't want to design them yourself (if you go this way, be sure to get a platinum club subscription. It gives you access to thousands of articles at a reduced price of 1.99$ and you can cancel at anytime)
Edit: to get an idea of what you can do, search "daz3d tutorial" on YouTube
Answer: Shade 3D has a free version called Shade 3D for Unity. You can build models, animate them, and freely exchange them back and forth with Unity 3D for testing purposes. It also works great with other development tools.

3D character modeling tool


Build rotational Hamiltonian based on Lagrangian of general form

Question: I've been told that one could build rotational Hamiltonian based on Lagrangian of general form: $\mathcal{L} = \mathcal{L} (\vec{\Omega})$. By introducing Euler angles one could rewrite Lagrangian in terms of Euler angles and their derivatives: $\mathcal{L} = \mathcal{L} (\vec{e}, \dot{\vec{e}})$.
Angular velocity is expressed in terms of Euler angles in a following way: $$\vec{\Omega} = \begin{bmatrix} \sin(\theta) \sin(\psi) & \cos(\psi) & 0 \\
                \sin(\theta) \cos(\psi) & - \sin(\psi) & 0 \\
                \cos(\theta) & 0 & 1 \end{bmatrix} \cdot \begin{bmatrix} \dot{\phi} \\ \dot{\theta} \\ \dot{\psi} \end{bmatrix}.$$ (Vector $\begin{bmatrix} \phi \\ \theta \\ \psi \end{bmatrix}$ is denoted by $\vec{e}$. ) Big problem that I encountered is that angular velocity depends on general velocity vector ($\dot{\vec{e}}$) in a linear way (by linear operator $\mathbf{M}(\vec{e})$ matrix of which is presented above), so general momentum $\vec{p_e} = \frac{\partial \mathcal{L}}{\partial \dot{\vec{e}}}$ is not an explicit function of general velocity vector($\dot{\vec{e}}$). That is Donkin's theorem or Legendre transform cannot be applied because general velocity components cannot be explicitly written as functions of $\vec{e}$ and $\vec{p_e}$.
Comment: I once took a class on Lie algebras where the focus was rigid body rotation in SO(3), and we developed discrete versions of Hamilton's equations using variational techniques directly for each problem; we then did computer simulations with these, obtaining a very high degree of stability.  The purpose of the class was to study techniques suitable for orbital calculations.  We used attitude rotation matrices as the working element; these are skew-symmetric matrices forming a Lie algebra in so(3). The class was very involved & cool.
Comment: Peter Diehr, and how discrete-time Hamiltonian be of any use here?
Comment: We got from Lagrangian to Hamiltonian; the method was different than yours, but I don't recall any theoretical impediments. But the Lagrangian was expressed ddifferently.
Answer: The Lagrangian is in fact an equation of $\vec \Omega$, however, in general it will be a quadratic function of $\vec \Omega$, as the rotational kinetic energy would be given by $$\frac{1}{2}\vec \Omega ^T \mathbf{I}\ \vec \Omega$$
This would give you the desired generalized momenta as a function of the general velocity vectors, as the diagonal entries of the moment of inertia tensor must not be zero, guaranteeing square velocity terms will appear in the Lagrangian. The exact form of the Lagrangian will depend on the object which is spinning, and its moment of inertia.
David Tong's notes go over the case of a rotational Lagrangian in terms of Euler angles for a symmetric top quite lucidly. From the explicit Lagrangian it is easy to see that $\frac{\partial^2 \mathcal{L}}{\partial \dot{\vec{e}}^2}$ is non-zero, allowing the application of the Legendre Transform.


1970-ish: Is it an accepted word? If so, what does it mean?

Question: Modish, youngish, girlish are accepted words. Is 1970-ish accepted too, or even understood to be an English word?
Answer: Acceptable or not depends on where you try to use it. New words are formed like this all the time, but in a more formal situation you would only use such words if they are already widely known.
The meaning of 1970-ish would depend on the situation. It can mean circa 1970:

They stopped manufacturing that model 1970-ish.

It can also mean in a 1970 style:

That lamp really looks 1970-ish.
Comment: I guess the first meaning is similar to the meaning of _hourish_, while the second meaning is someway similar to _girlish_.
Answer: Accepted? Don't know. I would print it. What it means: I'd expect either "circa 1970" or "in roughly the mode of the early 70s," depending on usage context.
Answer: I'm sure a few purists might object, but I would suggest that it will be accepted by the majority, in that they will be fairly clear in what is meant by the term.
Thinking about it further, I'm not beyond tagging -ish onto various other words or phrases myself. Hardly the heights of eloquence but it usually gets the message across, which is surely purpose of language.
Answer: Speaking in more general terms, when I append ish to a word, I'm usualy trying to convey the fact that I'm approximating.
So in your example, 1970-ish would mean around the period of the year 1970 and the listener would realise that I could be talking about any of the several years before or after 1970, but that I don't know which one in particular.
But it depends on the context in which you use it.
Answer: OED 2nd Ed supports -ish forming in your case.

2.2 Added to other ns., with the sense 'Of or belonging to a person or thing, of the nature or character of'. These were not numerous in OE., whence only a few have come down to later times. Examples are folcisc popular, hǽðenisc heathenish, þéodisc national, inlęndisc inlandish, utlęndisc outlandish (which come close to the gentile group in 1); also męnnisc human, cildisc childish, cierlisc churlish. In later times this ending has become exceedingly common, sometimes in the earlier colourless sense as boyish, girlish, waggish, but chiefly in a derogatory sense, 'Having the (bad or objectionable) qualities of': as in apish, babyish, boarish, boorish, brutish, clownish, currish, devilish, doggish, doltish, dronish, foolish, foppish, goatish, ghoulish, hoggish, impish, knavish, mannish, monkish, mulish, owlish, prudish, roguish, selfish, shrewish, sluggish, sluttish, sottish, swinish, thievish, waspish, whorish, wolvish, womanish. (These have usually corresponding Ger. forms in -isch.) Also from names of things, with sense 'of the nature of, tending to', as in aguish, blockish, bookish, brinish, feverish, freakish, hellish, moorish; or from other parts of speech, as snappish, stand-offish, uppish.
  In recent colloquial and journalistic use, -ish has become the favourite ending for forming adjs. for the nonce (esp. of a slighting or depreciatory nature) on proper names of persons, places, or things, and even on phrases, e.g. Disraelitish, Heine-ish, Mark Twainish, Micawberish, Miss Martineauish, Queen Annish, Spectator-ish, Tupperish, West Endish; all-over-ish, at-homeish, devil-may-care-ish, how-d'ye-doish, jolly-good-fellowish, merry-go-roundish, out-of-townish, and the like.

In the sentence :

He is a 1970-ish.

I would understand his character is back to 1970s.
Comment: Which case reported here suits for _1970-ish_?


Selenium downloads tmp file instead of CSV file

Question: When I download a CSV file from a blob URL, the downloaded file always has a ".tmp" extension and wrong file name. When downloading the same file manually, the file extension and file name both are correct. Any pointers will be helpful
Comment: Please share the code snippet.  Also, did you try in different browsers?
Answer: You will need to consider setting the Firefox profile with expected mime type for the content to be download.

BrowserOption with  Name = "browser.helperApps.neverAsk.saveToDisk"
  Value = "text/plain, application/vnd.ms-excel, text/csv,
  application/csv, text/comma-separated-values, application/download,
  application/octet-stream, binary/octet-stream, application/binary,
  application/x-unknown"

This worked in my case. When you are manually downloading the file, that time you will need to see for the mime type in developer tools else try using above while creating new Firefox session.


I need an StVZO compliant bike light. Any recommendations?

Question: I tried to buy one from Amazon but after testing it today the beam is clearly symmetrical and has no advantages over a normal bike light. I live in the UK so the StVZO regulation is not one which I have to comply with but I feel it is part of being a responsible road user. I'm open to the idea of having one that mount son my helmet.
Comment: Did you want a dynamo or battery power light?  stVZO compliance is more common for dynamo powered lights, although supernova and B&M makes stVZO compliant lights in both formats.
Comment: On quick search at least Sigma, Cat Eye, Axa, Garmin, Knog and BBB could be added to the list. And that's just from one store.
Comment: @Rider_X I was looking for USB stVZO lights
Answer: If you live in UK, you should have no problem ordering from Germany. The mail order houses there sell mostly lights that are street legal in their home country, and label non-compliant lights as off road only.
EDIT: The above goes for bike-mounted lights. Helmet-mounted lights do not seem to be under the same regulation.
If you absolutely must buy from UK, you can look up models on German sites and see if they are available in UK. Although, UK and continental Europe seem to be strangely separate markets even if they are in the same customs union.
Comment: I don't think helmet mounted lights can ever be stVZO compliant because one only has to tilt one's head to blind on-coming pedestrians and cars.
Comment: "UK and continental Europe seem to be strangely separate markets even if they are in the same customs union." Don't worry. This apparent contradiction will go away soon. \*sigh\*
Answer: The StVO laws for bicycle lights only define the minimum Voltage and some attributes like: "The Rear Light should not be able to blink".
The StVO should be updated to use Lumen instead of Voltage among other changes, and this might happen soon with Light Manufactors lobbying for these changes.
However, the StVO says very little about the quality of a light, it's visibility for other road users or the ability to help you with vision while riding.
It would be wiser to look for a Light with a beam that does not glare in the direction of the opposite traffic, is visible from the sides and bright enough to light your way.
Reading reviews might help you more than relying on years old german legislation.
We might be known for our accuracy and efficiency but not for our reasonable traffic laws.
Comment: Good point about lumens. I thought it was kind of obvious but yes, any light that is dim enough probably passes. I doubt the voltage regulations are taken seriously because for LEDs the input voltage and drive voltage can be anything.


How does EOS prevent the double spend problem if the block times are only a few seconds?

Question: Bitcoin has the double spend problem where a user can spend the funds twice by sending from the same private key at once. The 10 minute block times prevent this, but how does EOS prevent something like this if block times are only a few seconds?
Comment: block times are subsecond (0.5s)
Answer: EOS requires 15/21 of the producers to sign a block in order to finalize it. Once 15 producers have signed a block the block is deemed irreversible.

Byzantine Fault Tolerance is added to traditional DPOS by allowing all
  producers to sign all blocks so long as no producer signs two blocks
  with the same timestamp or the same block height. Once 15 producers
  have signed a block the block is deemed irreversible. Any byzantine
  producer would have to generate cryptographic evidence of their
  treason by signing two blocks with the same timestamp or blockheight.
  Under this model a irreversible consensus should be reachable within 1
  second.

refer: https://github.com/EOSIO/Documentation/blob/master/TechnicalWhitePaper.md
Answer: Bitcoin employs UTXO (Unsigned transaction output) model, where unspent bitcoins will be input for your next transaction,
Eth ans Eos uses account based model.
the main catch is here is that you have only one read and write operation per account per block,
this eliminates the user broadcasting multiple txs in same block


Dealing with angry iron golems without a bow

Question: Is there a way to make iron golems friendly again/return to their original state?
One day in a village I was collecting wheat, and suddenly a villager stepped in front of me right as I was harvesting a stalk, and I accidentally punched the villager. Then the local iron golem came and started to attack me, so I ran into my house. I'm trapped inside because the golem is faster than me.
Answer: An iron golem works like the wolf in terms of aggresivity, so you should do the following.

Gather up 3-4 stacks of dirt or other scaffolding.
Break out of the house through the ceiling and pillar up 10-15 blocks.
While crouching, build your way out of the village until the village's chunks don't render anymore. The iron golem will not follow you outside the village limit because of it's AI.
Get down safely.
Wait for at least 20 minutes. (IRL)
You can now re-enter the Village safley.

P.S. An alternative is quickly opening the door to your house, hitting the golem and closing it again. Rinse and repeat until dead.
Comment: PPS: An alternative to the alternative is to build a murder-hole: a 1-block  opening which lets you punch the golem.
Comment: Ill try that thx
Comment: Digging might also be an option
Answer: I don't quite remember, but I believe that killing the Golem might affect Villager happiness. So your options are to either run away (as Detmondyou has suggested), die, or rebuild villager happiness after you have killed the golem.
In the case of dying to the Golem, the main concern is loss of inventory. You can either set your spawn by building a bed, sleeping, then going out the next morning and dying to the golem, or you can change the gamerules to allow you to keep your inventory upon death. To do this:

If you don't have cheats allowed in your game, open the game to LAN, and allow cheats

Pause > Open to LAN > Allow Cheats: True

In the chat, type: /gamerule keepInventory true (you can copy and paste it from here - the capital "I" is important).

Now, when you die, you will respawn in your spawn location with all of your inventory, and all your XP; and the Golem (having dealt with the threat) will no longer be aggro'd.

Note: if you use the "Open to LAN" option to allow cheats in game, this will be the case until you turn it off again by opening your game to LAN (it will automatically close each time you exit your game). You can also switch your gamerule back (if you wish) by setting it to false, with cheats allowed:
/gamerule keepInventory false
Comment: You can also store your belongings in a chest to counter the entity despawn timer.
Answer: You can just quit the game then start it again and it should be friendly
Comment: Can you back up your claim?
Answer: You could go into Peaceful difficulty and then kill it since it won't be mad anymore.
Answer: TL;DR- Get far away from the golems and they will stop trying to attack you.
A golem and I both went for the same zombie. I hit the golem on accident. I yelled, "I'm sorry! I'm sorry! I'm sorry!", as I ran for cover inside my house.
The golem and his 3 buddies (large village) started chasing me! I found cover and stood inside the tiny little 4x4 interior of the house, while the 4 golems circled, looking for a way to get me.
At one point, I got too close to the window and the golems hit me through the wall. So beware that's a thing, if anyone is in a similar situation.
I came here and found this post, looking for an answer. Not seeing any way to tame these 4 angry golems, I decided to run for the edge of the village and then wait for the timeout.
I stepped to the back of the house, so the golems would circle around there, then I ran for the door, out onto the narrow path between my house and the building next to me, hoping I could get around that building before the golems caught up with me. I ran to the edge of the village (or as far as I thought I should)
When I turned around to see where the golems were, I only saw one that had followed and he was 50 or so blocks behind me, standing there looking for me. After a few seconds, he turned around and went on his way.
I decided to make my way around to the side of the village, where I found 2 of the golems hanging out in a field with a couple of villagers. I approached cautiously, until I saw the golems recognize me. Neither of them came after me, so I assume they had lost their agro against me.
I cautiously made my way back through the village, testing the other golems and found I was in the clear.
So... They obviously changed the agro logic in the Bedrock edition of Minecraft. This whole event lasted maybe 5 minutes.
Comment: There is a lot of (entertaining but) unnecessary filler here. Your answer seems to be 'run outside of the city and the golems will turn passive'. In that sense it adds nothing to the approved answer.
Comment: The approved answer states you need to wait 20 minutes before re-entering. That was not required in my case. I shared my experience, so people could understand exactly what transpired.


Running Windows 2008 VPS with Hyper-V on UltimaHosts.Net Server

Question: I've got an interesting issue running Active Directories within a Windows 2008 VPS R2 Hyper-V on an UltimaHosts.net server. Basically the install fails half way through with the error being that I don't have enough permission to complete the task. Looked up the KB but found no help there. Any ideas what is going wrong?
Comment: Are you logged in as local administrator?
Answer: I'm guessing (since you didn't post an error code) but my first suspect would be that you either chose their DNS server or didn't set that server up as one first.  The task that it can't complete would be creating the SRV records in DNS.  Install that server with the DNS server role first for the domain that you own (or use a pseudo-domain for your TLD like mydomain.internal) then install active directory and when asked point it toward your new DNS server.


Draping 2D image over point cloud or mesh

Question: I'm new to blender and could not find this in help files. Can blender be used to drape a 2D image onto a 3D point cloud or mesh? If yes, can someone point me to a tutorial on that?
Comment: You could try a shrinkwrap modifier, see http://blender.stackexchange.com/q/7028/599
Comment: Thanks. I guess this is good for creating surfaces out of point clouds. What I want is the ability to drape an image onto a mesh or point cloud.
Comment: What do you mean by "drape"? Do you want to texture it? Or drape a mesh with a texture (like stacker's answer)?
Comment: I actually have point cloud of a surface from a LiDAR unit as well as a picture taken with a camera. I want to drape that image over the point cloud to get a 3D realistic model of the surface.
Answer: To drape an image over a 3d mesh is easy.
First bring you image into blender, I'd use the import image as plane add on. Next, as gandalf3 said, use a shrink wrap modifier to drop it over the mesh. by doing that you can avoid any distortion that would occur when using the cloth simulator.
Answer: If you want to project camera data on to a LIDAR scan, I would use a third method:

Match your 3D camera to the position of the camera that took the photograph.
Next select your mesh(LIDAR scan), and add a UVProject Modifier.
Set the projector to you camera you positioned in step one.
Then set your image in the image box.
Uv Unwrap your mesh(LIDAR scan), It does not matter how. Also change the UV option in the UV project modifier to match the name of the UV map you just created.
Add a texture, and set the image to be your photograph. also set the UV map.

Done, your mesh(LIDAR scan) has been textured!
Comment: Sounds like it would work but the position of the camera is not known. I guess shrinkwrap would be the next closest option?
Comment: You can solve for the position of the camera using something like blam(https://github.com/stuffmatic/blam), or eyeballing it.
Answer: I've done this kind of thing before-adding an orthoquad photo as a texture on surface mesh to make a realistic land form. The crucial step is going to be converting that Lidar data into a TIN surface (triangulated irregular network) that you can then export as a mesh to Blender.
If your LIDAR data comes from a survey firm, then the best option is to ask them to create a DXF file for you.
You can then open that in DRaftsight (it's free: Draftsight.com) and export it to STL-which you can then import into Blender.
Another option: I found a web portal that says registration is free and that members have access to Lidar conversion tools that can craete DXF or Collada files. Here is their URL: https://www.lidar-online.com/users-login.php
Finaly, If you acquired the point data from one of the public domain USGS sites (like LaBIns.org) then check to see if you can get the data in DEM format.  The DEM is a zip file containing amoung other things, a raster image of a displacement map.  Elevation values are represented as shades of gray.  change the file extension to .zip so that you can view it in your file system.  Extract that and then you can apply image as a displacement modifier to a plane, or wire it to the displacement channel of your ground-plane material
One final bit of advice on using these files in Blender.  Before you import them, you need to be sure of your units and precision settings.  Cadastral data is usually georeferenced using special coordinate systems.  Your data set could come in very far from the origin in your scene or might be expressed in lattitude/longitude, so you should move and scale your data after you import it.
Comment: Thanks, John. I'm using VRMesh to create the TIN and can export the mesh in blender as well. I couldn't quite get how you did the draping. Can you please elaborate on it a bit? Thanks.
Comment: If your iamge is ortho-rectified (and most Arial mapping images are), then you can just do a simple UV projection.
Edit the surface tin, set the view to orthographic looking at it from the top down, select all of the triangles in the mesh (A), go into the UV Unwrap (U) and select "Project from View"
Comment: The image is not orthorectified. It's actually not an aerial image, rather of a vertical surface taken with a simple handheld camera.
Comment: Sounds like GiantCowFilms had the right approach, then.


Winter tires 195/55r16 fit on a 16x7 rim

Question: Hello I was wondering if I can use winter tires 195/55r16 on a 16x7 rim? Or can I use another 195/ which fit better ?
Answer: The only 2 concerns about fitting a tire to a wheel are the diameter (they must be a perfect match), and the width (there's a range of widths that will fit).
In your case, you are fitting a 16" tire into a 16" wheel, so we only need to look at the width. According to , 195 is the minimum width you can fit safely on a 7" wide wheel. Any 195 width tire will fit the same, changing the aspect ratio will only mess-up your speedometer and odometer.
Is 195/55R16 your OEM tire size?
Comment: On my Mercedes are the 16x7 rims and want to install 195/55r16 just want to make sure that will not course Amy problem. I have notice buying 195 are cheaper and better in snow
Comment: What is your OEM tire size? You need to make sure the circumference still matches.
Comment: My regular size tire is 205/55r16


Where can I find the English translation of the Vedas?

Question: I am aware of Griffith's translation. But I am not very satisfied with that. Is there any other translation available?
Comment: It's always better to read translations of Indian Authors rather than in English by foreign authors.
Comment: Max Mueller also did a translation. You can google his name to find.
Comment: Yes, that is why I think Tulsi Ram's translation from Arya Samaj is very important. But the problem is I am not able to find Tulsi Ram's translation of Rig Veda and Atharva Veda!
Comment: Max Mueller RigVeda Samhitha  is available in several state libraries.
Answer: I have found a few links!
Rig Veda:
Rig Veda Samhita by Max Muller Thanks to Swami Vishwananda for this link!
One of the best translation along with detailed commentary.
The Rigveda: 3-Volume Set by Stephanie W. Jamison and Joel P. Brereton
Yajur Veda:
This pdf file has watermarks.
Yajur Veda English translated by Dr Tulsi Ram. Arya Samaj e library
Sama Veda:
This pdf file has watermarks.
Sama Veda English translated by Dr Tulsi Ram. Arya Samaj e library
Atharva Veda: translated by Dr Tulsi Ram
https://archive.org/details/susmitaroychowdhury512_gmail_20180202
All volumes of four Vedas - The best collection:
To get the English translation of all 4 Vedas by Dr Tulsi Ram, please go to the following link. Dr Tulsi Ram's translation is the best. By the way, the filenames are in Bengali, but the books are in English! So do not get confused.
https://archive.org/details/susmitaroychowdhury512_gmail
These pdf files have an annoying yellow background colour. However, with any pdf editor (for example, PDF XChange editor) you can easily remove all background colour and can get pure white background! Otherwise, file qualities are excellent. Files are small and they do not have any watermark. Most importantly files are not protected, which means you can annotate these pdf files easily!
Answer: sacred texts.com provide various hindu scriptures to read free and downloadable too.
Translator: Ralph T. H. Griffith, 1896
link— http://www.sacred-texts.com/hin/
1-Rigveda
2-samaveda
3-white yajurveda/shukla yajurveda
3-black yajurveda/krishna yajurveda or taittrayi samhita
4-atharvaveda
for download in english and hindi :— http://www.patheos.com/blogs/hindu2/2016/03/vedas-the-4-vedas-in-hindi-english-telugu-pdf-download/
&
for total english:— https://archive.org/details/FourVedasEnglishTranslation?_e_pi_=
Comment: Thanks for uploading the links to Griffith's translations. I was actually looking for other translations. But anyways these links are also useful.
Comment: @amritendu check last download links they are not all of Ralph T.H. griffith it was by mistake set to direct download but i edited and made it detailed one.
Comment: The OP is  already   aware of  Griffith's translation. And want the other ones.


Aircrack-ng: Why deauth works

Question: When using aircrack to attack WPA, deauth packets are used to force a host to deauthenticate. But the machine sending these deauth packets is not even connected to the network. How possible is it that the AP accepts packets from a machine not connected to it? In other-wards, why would an AP or end host accepts de-authentication requests from arbitrary senders who are not even connected to the network?
Answer:
AP accepts packets from a machine not connected to it
  from arbitrary senders

Normally, deauthentication [and other management] frames don't have to be encrypted (i.e. require an existing authenticated 'connection' between the AP and the client). Therefore, they can be spoofed.
The way to protect against this kind of attack is to use Management Frame Protection (check out http://www.cisco.com/c/en/us/support/docs/wireless-mobility/wlan-security/82196-mfp.html#climfp):

Specifically, client MFP encrypts management frames sent between access points and CCXv5 clients so that both access points and clients can take preventive action and drop spoofed class 3 management frames (that is, management frames passed between an access point and a client that is authenticated and associated). Client MFP leverages the security mechanisms defined by IEEE 802.11i to protect these types of class 3 unicast management frames: disassociation, deauthentication, and QoS (WMM) action.

What are the legitimate uses for deauth frame?
In addition to just that, termination of the secure communication (e.g. 'Forget this network'), there are a few possible reasons specified by 802.11, like these (reason/description):

2 - Previous authentication no longer valid
3 - Station is leaving (or has left) IBSS or ESS
4 - Disassociated due to inactivity

(you can read more at, for example, https://supportforums.cisco.com/document/141136/80211-association-status-80211-deauth-reason-codes or  )
Why is it that Access Points do not implement these Management Frame Protection mechanisms?
It is available in many APs, but usually "Optional" by default, to prevent client connectivity issues. You can read more in this answer: 802.11w protected management frames - Wi-Fi
Personally, I think that it is not such a big deal, because (a) strong PSKs make bruteforcing long and non-so-effective, (b) you can just wait for a legitimate client to leave and come back to catch the handshake. I.e. it makes it harder to get in, but doesn't prevent the possibility.
Comment: Why is it that Access Points do not implement these Management Frame Protection mechanisms ? It appears all Wi-Fi networks today are vulnerable to spoofing of deauth packets. Why are these mechanisms not used?
Comment: Also, can you please clarify on the purpose of deauth packets in practice? I know how they help to aid  attacks, but I am not sure of their legitimate purpose when a network operates normally
Comment: @Minaj added some info the the answer
Comment: Thanks. One more question: when attacking WPA, why is it that a single deauthenticate message is normally not enough to cause deauthentication? One usually has to send multiple messages to achieve deauthentication. Not sure why this is the case. Any ideas?
Comment: @Minaj I think it's because not all packets are actually received - either due to distance, signal strength, or something else; aircrack even shows you number of ACKs from AP and the client for the deauth packets

Aircrack-ng: Why deauth works


Did playing Hearthstone during the beta grant any benefits that can't be matched by playing the game later?

Question: Playing Hearthstone during the beta might have granted players more experience as well as more cards to play with. These are both benefits that may be matched by playing more later. However, some games grant beta players exclusive content such as gear or achievements that players get to keep even after the beta. To players that didn't play the beta, this content would then be lost forever. Did playing the Hearthstone beta grant beta players any such content?
Answer: There are a few pieces of exclusive content thusfar in Hearthstone. The first is a golden 'Gelbin Mekkatorque' card, that could be earned by using real money to make a purchase in Hearthstone while it was in the beta.

The golden version of this card is no longer obtainable. It was previously obtained by spending real money in the store during the game's beta test, prior to the full release of the game.

In addition, golden 'Elite Tauren Chieftain' was only earnable through purchasing a ticket to Blizzcon 2013, and thus also can't be earned any longer.
However, the normal version of each of these cards are still both able to be earned through crafting them.
Card backs will likely be exclusive to each season and event, such as the ones earned through levels in ranked on specific seasons, but thusfar, I haven't seen anything specific about this yet.
Comment: @waterseas That's just it: I never went to the shop. There didn't seem much point in investing in something that wasn't finished yet :) My loss.
Comment: Small correction; Gelbin and ETC aren't in packs
Comment: But during the beta Gelbin got significantly nerfed from OP card to useless card.
Comment: Nerfed or not, it still irks me that I never found this out during the beta, and missed out on a card. I buy packs now, so I may as well have bought one during testing :)
Comment: @BazzPsychoNut He's still a very fun card, and is decent in the right deck. I have three different creature spam decks that run him because, for the most part, he's pretty good if you are the only person with creatures. Unless he brings Poultreyizer ><
Comment: @MattThrower During the beta, I believe he was advertised as being earn-able in the actual client himself if you went to the shop.
Answer: The only thing from the beta that can't be acquired anymore is the golden version of Gelbin Mekkatorque (for buying something with real money during the beta). The normal version of this card can still be crafted.
Also there is Elite Tauren Chieftain of which the golden version can't be acquired any more. That was granted by buying a Blizzcon 2013 ticket.


Video sharing in Windows phone( Lumia 720)

Question: I am using Nokia lumia 720 which is an awesome phone but lacks a very basic requirement that is sharing Video through bluetooth. Can anyone tell me when it will be developed and released? Is Microsoft looking after this issue?
Answer: It's nearly impossible to guess what features will appear in future version of Windows Phone unless the information is leaked or Microsoft explicitly say a feature is coming (eg. Rotation Lock on GDR3/Update 3).
As a Windows Phone user, all you can is search through the Feature Suggestion site (UserVoice) and see if the feature idea has already been submitted.
In the case of sharing videos via Bluetooth, it looks like the idea has been submitted a couple of times but doesn't have many votes. Maybe adding your votes will help?
Answer: Well i have sorted out the method of sharing video.
make sure the vidoes are saved in phone memory in the camera roll folder.
Open the camera roll folder and tap the vidoe then a sharing option will appear. Select bluethooth option & share.


How do I import the javax.servlet / jakarta.servlet API in my Eclipse project?

Question: I want to develop with Servlets in Eclipse, but it says that the package javax.servlet / jakarta.servlet cannot be resolved. How can I add javax.servlet / jakarta.servlet package to my Eclipse project?
Comment: im trying to run a simple hello word type servlet, normally if i wanted to make a gui i would import java......swing.*; i cant find the right import for a servlet
Answer: Ensure you've the right Eclipse and Server version
Ensure that you're using at least Eclipse IDE for Enterprise Java (and Web) developers (with the Enterprise). It contains development tools to create dynamic web projects and easily integrate servletcontainers (those tools are part of Web Tools Platform, WTP). In case you already had Eclipse IDE for Java (without Enterprise), and manually installed some related plugins, then chances are that it wasn't done properly. You'd best trash it and grab the real Eclipse IDE for Enterprise Java one.
You also need to ensure that you already have a servletcontainer installed on your machine which implements at least the same Servlet API version as the servletcontainer in the production environment, for example Apache Tomcat, RedHat WildFly, Eclipse GlassFish, etc. Usually, just downloading the ZIP file and extracting it is sufficient. In case of Tomcat, do not download the EXE format, that's only for Windows based production environments. See also a.o. Several ports (8005, 8080, 8009) required by Tomcat Server at localhost are already in use.
A servletcontainer is a concrete implementation of the Servlet API. Also note that for example WildFly and GlassFish are more than just a servletcontainer, they also support JSF (Faces), EJB (Enterprise Beans), JPA (Persistence) and all other Jakarta EE fanciness. See also a.o. What exactly is Java EE?
Ensure that you're using the right Servlet package
The javax.* package has been renamed to jakarta.* package since Servlet API version 5.0 which is part of Jakarta EE 9 (Tomcat 10, TomEE 9, WildFly 22 Preview, GlassFish 6, Payara 6, Liberty 22, etc). So if you're targeting these server versions or newer, then you need to replace
import javax.servlet.*;
import javax.servlet.http.*;

by
import jakarta.servlet.*;
import jakarta.servlet.http.*;

in order to get it to compile, else you might risk to face this build error

The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path

Integrate Server in Eclipse and associate it with Project
Once having installed both Eclipse for Enterprise Java and a servletcontainer on your machine, do the following steps in Eclipse:

Integrate servletcontainer in Eclipse
a. Via Servers view

Open the Servers view in the bottom box.

Rightclick there and choose New > Server.

Pick the appropriate servletcontainer make and version and walk through the wizard.

b. Or, via Eclipse preferences

Open Window > Preferences > Server > Runtime Environments.

You can Add, Edit and Remove servers here.

Associate server with project
a. In new project

Open the Project Navigator/Explorer on the left hand side.

Rightclick there and choose New > Project and then in menu Web > Dynamic Web Project.

In the wizard, set the Target Runtime to the integrated server.

b. Or, in existing project

Rightclick project and choose Properties.

In Targeted Runtimes section, select the integrated server.

Either way, Eclipse will then automatically take the servletcontainer's libraries in the build path. This way you'll be able to import and use the Servlet API.

Never carry around loose server-specific JAR files
You should in any case not have the need to fiddle around in the Build Path property of the project. You should above all never manually copy/download/move/include the individual servletcontainer-specific libraries like servlet-api.jar, jsp-api.jar, el-api.jar, j2ee.jar, javaee.jar, etc. It would only lead to future portability, compatibility, classpath and maintainability troubles, because your webapp would not work when it's deployed to a servletcontainer of a different make/version than where those libraries are originally obtained from.
In case you're using Maven, you need to make absolutely sure that servletcontainer-specific libraries which are already provided by the target runtime are marked as <scope>provided</scope>. You can find examples of proper pom.xml dependency declarations for Tomcat 10+, Tomcat 9-, JEE 9+ and JEE 8- in this answer: How to properly configure Jakarta EE libraries in Maven pom.xml for Tomcat?
Here are some typical exceptions which you can get when you litter the /WEB-INF/lib or even /JRE/lib, /JRE/lib/ext, etc with servletcontainer-specific libraries in a careless attempt to fix the compilation errors:

java.lang.NullPointerException at org.apache.jsp.index_jsp._jspInit
java.lang.NoClassDefFoundError: javax/el/ELResolver
java.lang.NoSuchFieldError: IS_DIR
java.lang.NoSuchMethodError: javax.servlet.jsp.PageContext.getELContext()Ljavax/el/ELContext;
java.lang.AbstractMethodError: javax.servlet.jsp.JspFactory.getJspApplicationContext(Ljavax/servlet/ServletContext;)Ljavax/servlet/jsp/JspApplicationContext;
org.apache.jasper.JasperException: The method getJspApplicationContext(ServletContext) is undefined for the type JspFactory
java.lang.VerifyError: (class: org/apache/jasper/runtime/JspApplicationContextImpl, method: createELResolver signature: ()Ljavax/el/ELResolver;) Incompatible argument to function
jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/servlet/Servlet.class
Comment: @BalusC If I am using Apache Ant to build my project, how do I include the /lib(servlet-api.jar & jsp-api.jar) folder of servlet container dynamically ? Or do I need to hard code the path to the /lib folder like - `` etc
Comment: @BalusC why are maven projects created with archetype `maven-archetype-webapp` not including the servlet-api JAR as a dependency? The project has an index.jsp with compile error. (Eclipse Luna Build id: 20140612-0600, JDK 8, M2eclipse)
Comment: @arun `servlet-api` dependencies are provided by the Servlet runtime environments like Tomcat, Wildfly, Glassfish, etc.,. Don't ever include it as part of your app, as there's a good possibility of it clashing with the environment's.
Comment: @BalusC, What you saying is some kind of abstract for me. I am new to Java. Maybe I still don't understand some concept of Java. So, could you please give me a feedback of the previous commnet of my questions. And I would like to append some clarification for my question: From my thinking, JCP(or Oracle) will provide a jar, which only contains interfaces of Servlet, for example the jar of javax.servlet-api-3.1.0.jar. The other vendors who want to deliever their own Servlet should implement the interfaces(another choice is they follow the JCP doc, then give their own interface and implement)
Comment: @BalusC, 1) Is javax.servlet-api-3.1.0.jar equal to tomcat8/lib/servlet-api.jar? I decompile the two jars, then find moust of the classes/interfaces are the same. 2) Is javax.servlet-api-3.1.0.jar container-neutral(not servletcontainer-specific libraries)?
Comment: @gfan: technical problem is not whether container-provided libraries are "container neutral" but classloading precedence and ordering. If container-provided libraries are loaded by the wrong classloader (e.g. via webapp classloader), things may go havoc, even if it's "coincidentally" exactly the same version. Just do not provide container-provided libraries from duplicate places outside container. Period.
Comment: We should always using APIs in projects, If we want to run the projects we shoud use Reference Implementation. APIs like a shell, It's empty inside. but the refererence Implementation is concrete. javax.servlet-api-3.1.0.jar is just the shell, when code is running, we have to fill it with staffs, tomcat's servlet-api is a shell and a staff. Am I right?
Comment: Converting the project to maven project (in Eclipse, right click on project -> Configure -> Convert to maven project) solved.
Answer:
STEP 1
Go to properties of your project ( with Alt+Enter or righ-click )
STEP 2
check on Apache Tomcat v7.0 under Targeted Runtime and it works.
Comment: Helped me add my JBOSS runtime. My list was empty.
Comment: This was the solution for me.

I had set tomcat 6.0 as my deployment enviournment(as a server in eclipse), but neglected to specify it as my runtime enviournment... I'm guessing that means it could find the .jars in my tomcat/lib folder at runtime, but not at compile time.
Comment: This works! Thanks, @mrgloom, you may want to remove the server and create a new server in your localhost
Comment: Thanks! But how can I delete copies of mu servers? I have Apache Tomcat v7.0 (2) and (3) that I want to delete. Anyone knows how?
Comment: Not helped me to solve problem with `The import javax.servlet cannot be resolved`.
Comment: What if I can't see tomcat in this list?
Answer: Little bit difference from Hari:

Right click on project ---> Properties ---> Java Build Path ---> Add Library...  --->  Server Runtime ---> Apache Tomcat ----> Finish.
Comment: Hi ivanLam, Apache Tomcat is not showing after Server Runtime? What to do now!
Answer: Add javax.servlet dependency in pom.xml. Your problem will be resolved.
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>3.0.1</version>
    <scope>provided</scope>
</dependency>

Answer: Include servlet-api.jar from your server lib folder.
Do this step
Comment: Solution is not working for me still getting below error
A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/messenger]]
Answer: Quick Fix- This worked in Eclipse - Right Click on project -> Properties -> Java Build Path (Tab) -> Add External JARs -> locate the servlet api jar implementation (if Tomcat - its named servlet-api.jar) -> click OK. That's it !!
Comment: With reference to above BalusC post    never manually copy/download/move/include the individual servletcontainer-specific libraries like `servlet-api.jar`, `jsp-api.jar`, `el-api.ja`r, `j2ee.jar`, `javaee.jar`, etc. It would only lead to future portability, compatibility, classpath and maintainability troubles.
Answer: For maven projects add following dependancy :

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>3.0.1</version>
    <scope>provided</scope>
</dependency>

Reference
For gradle projects:
dependencies {
providedCompile group: 'javax.servlet', name: 'javax.servlet-api', version: '3.0.1'
}

or download javax.servlet.jar and add to your project.
Answer: you can simply copy the servlet-api.jar and copy that jar files into lib folder, which is in WEB-INF.
then just clean and built your project, your errors will be solved.
  **OR**

you can directly add jar files to library by using following steps.

Right click on project.
Go To Properties.
Go to Java Build Path.
Select Add Library option from tabs.
Add Jar Files
give path of your servlet-api.jar file.
Clean and build your project.
Comment: Downvoting, with reference to above BalusC post and  Aniket Kulkarni comment, never manually copy/download/move/include the individual servletcontainer-specific libraries like `servlet-api.jar`, `jsp-api.jar`, `javaee.jar`, etc. It would only lead to future portability, compatibility, classpath and maintainability troubles.
Answer: I know this is an old post. However, I observed another instance where in the project already has Tomcat added but we still get this error. Did this to resolve that:

Alt + Enter
Project Facets
On the right, next to details, is another tab "Runtimes".
The installed tomcat server will be listed there. Select it.

Save the configuration and DONE!
Hope this helps someone.
Answer: From wikipedia.
import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloWorld extends HttpServlet {
  public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    PrintWriter out = response.getWriter();
    out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 " +
                "Transitional//EN\">\n" +
                "\n" +
                "<title>Hello WWW</title>\n" +
                "\n" +
                "
Hello WWW
\n" +
                "");
  }
}

This, of course, works only if you have added the servlet-api.jar to Eclipse build path. Typically your application server (e.g Tomcat) will have the right jar file.
Answer: I was getting a null pointer exception during project creation related to "Dynamic Web Module".
To get the project to compile (that is, to javax.servlet to import successfully) I had to go to project's Properties, pick Project Facets in the sidebar, tick Dynamic Web Module and click Apply.
Surprisingly, this time "Dynamic Web Module" facet installed correctly, and import started to work.
Comment: To add to this, for Tomcat 10.x, I changed Project Facet setting for the "Dynamic Web Module" to a newer one.  In my case, this changed to version 5.0 after which the index.jsp file no longer showed an issue on the html tag.  Prior to this it was configured to 2.3 (i.e. pre-jakarata) which was not applicable for Tomcat 10.x which leverages the jakarta namespace instead of the java namespace.
Answer: In my case, when I went to the Targetted Runtimes, screen, Tomcat 7 was not listed (disabled) despite being installed.
To fix, I had to go to Preferences->Server->Runtime Environments then uninstall and reinstall Tomcat 7.
Answer: Many of us develop in Eclipse via a Maven project. If so,
you can include Tomcat dependencies in Maven via the tomcat-servlet-api and tomcat-jsp-api jars. One exists for each version of Tomcat. Usually adding these with scope provided to your POM is sufficient. This will keep your build more portable.
If you upgrade Tomcat in the future, you simply update the version of these jars as well.
Answer: This could be also the reason. i have come up with following pom.xml.
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </exclusion>
    </exclusions>
</dependency>

The unresolved issue was due to exclusion of spring-boot-starter-tomcat. Just remove <exclusions>...</exclusions> dependency it will ressolve issue, but make sure doing this will also exclude the embedded tomcat server.
If you need embedded tomcat server too you can add same dependency with compile scope.
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-tomcat</artifactId>
    <scope>compile</scope>
</dependency>

Answer:

You should above all never manually copy/download/move/include the individual servletcontainer-specific libraries like servlet-api.jar

@BalusC,
I would prefer to use the exact classes that my application is going to use rather than one provided by Eclipse (when I am feeling like a paranoid developer).
Another solution would be to use Eclipse "Configure Build Path" > Libraries > Add External Jars, and add servlet api of whatever Container one chooses to use.
And follow @kaustav datta's solution when using ant to build - have a property like tomcat.home or weblogic.home.
However it introduces another constraint that the developer must install Weblogic on his/her local machine if weblogic is being used !
Any other cleaner solution?
Answer: Assume a simple dynamic Web Project. Ensure Tomcat is present on the project's build path.
First get the local tomcat instance downloaded/installed on your machine. Assume we installed tomcat v8.5.
Now configure the Eclipse Global Server Run time Environment
Windows > Preferences > Server > Runtime Environments > Add > Apache > Apache Tomcat v8.5 > Next > Browse Tomcat Installation directory > Next > Finish.

Now create your dynamic web project and we see the import javax.servlet cannot be resolved issue. Resolve this by following below.
Right Click On Project > Build Path > Configure Build Path > Libraries > Add Library > Server Runtime > Select your Apache Tomcat instance > Finish > Apply and Close.

All Errors will be gone.
Answer:
ISSUE
Description Resource Path Location Type The default superclass, "javax.servlet.http.HttpServlet", according to the project's Dynamic Web Module facet version (2.3), was not found on the Java Build Path. index.jsp /FileUploadDemo/src/main/webapp line 1 JSP Problem

Eclipse IDE

eclipse-jee-2023-12-R-win32-x86_64
Version: 2023-12 (4.30.0)
Build id: 20231201-2043

Created a maven project with the following archtype

Catalog: Internal
ArtifactID: maven-archetype-webapp
Version: 1.0

Fixed the issue by upgrading the versions of Dynamic Web Module and Java version


Do negative probabilities/probability amplitudes have applications outside quantum mechanics?

Question: Quantum Mechanics has generalized probability theory to negative/imaginary numbers, mostly to explain interference patterns, wave/particle duality and generally weird things like that. It can be seen more abstractly, however, as a noncommutative generalisation of Bayesian probability (quote from Terrence Tao). I'm curious about these things, though by no means an expert. Does this have any applications outside Quantum Mechanics? Just curious.
Comment: Well, kind of. I'm by no means an expert either, but I read [THIS](http://www.espenhaug.com/NegativeProbabilitiesHaug.pdf) article by Esben Haug and found it quite interesting.
Comment: You could interpret the calculations I perform at https://stats.stackexchange.com/a/332122/919 (*inter alia*) as involving "negative probabilities" because they represent probability distributions as mixtures of positive and negative measures.  I take it, then, that by "application" you mean a *conceptual* one, not just a mathematical manipulation.
Answer: Yes.  I like the article Søren shared very much, and together with the references in that article I would recommend Muckenheim, W. et al. (1986). A Review of Extended Probabilities. Phys. Rep. 133 (6) 337-401.  It's a physics paper for sure, but the applications there are not all related to quantum physics.
My personal favorite application relates to de Finetti's Theorem (also Bayesian in flavor):  if we don't mind negative probabilities then it turns out that all exchangeable sequences (even finite, perhaps negatively correlated ones) are a (signed) mixture of IID sequences.  Of course, this itself has applications in quantum mechanics, in particular, that Fermi-Dirac statistics yield the same type of (signed) mixture representation that Bose-Einstein statistics do.
My second personal favorite application (outside of physics proper) relates to infinite divisible (ID) distributions, which classically includes normal, gamma, poisson, ... the list continues.  It isn't too hard to show that ID distributions must have unbounded support, which immediately kills distributions like the binomial or uniform (discrete+continuous) distributions.  But if we permit negative probabilities then these problems disappear and the binomial, uniform (discrete+continuous), and a whole bunch of other distributions then become infinitely divisible - in this extended sense, please bear in mind.  ID distributions relate to statistics in that they are limiting distributions in generalized central limit theorems.
By the way, the first application is whispered folklore among probabilists and the infinite divisibility stuff is proved here, an informal electronic copy being here.
Presumably there is a bunch of material on arXiv, too, though I haven't checked there in quite some time.
As a final remark, whuber is absolutely right that it isn't really legal to call anything a probability that doesn't lie in $[0,1]$, at the very least, not for the time being. Given that "negative probabilities" have been around for so long I don't see this changing in the near future, not without some kind of colossal breakthrough.
Comment: +1. It sounds like your "negative probabilities" are just signed measures, right?
Comment: Thanks.  Yes, exactly right, mine are.  Those of Khrennikov mentioned in the Haug are entirely different, though, they are limits of relative frequencies in some sort of p-adic topology.  Wild, crazy stuff.
Comment: It seems silly to say that we can't call them probabilities. It seems akin to saying I can't call imaginary numbers "numbers" as well.
Answer: QM does not use negative or imaginary probabilities: if it did, they would no longer be probabilities!
What can be (and usually is) a complex value is the quantum mechanical wave function $\psi$.  From it the probability amplitude (which is a bona fide probability density) can be constructed; it is variously written $\langle\psi|\psi\rangle$ or $\|\psi\|^2$.  When $\psi$ has (complex) scalar values, $\|\psi\|^2 = \psi^* \psi$.  In every case these values are nonnegative real numbers.
For details, see the section on "Postulates of Quantum Mechanics" in the Wikipedia article.
Comment: Right, so the idea being that state interactions can interfere and then the **intersection** of two states can "be negative".
Comment: Actually the signed probability formalization is not the wave function formalization. For a spinless point particle, the wave function is from space to $\mathbb{C}$: $x\mapsto\psi(x)$. The signed distribution formalization is on the phase space to $\mathbb{R}$: $(x,q)\mapsto p(x,q)$. See https://en.wikipedia.org/wiki/Wigner_quasiprobability_distribution. Well the question was unclear about which it refereed to.
Answer: I'm of the opinion that the "What's the application of this theory?" is a question that students of a theory should have to answer. Professor McGonagall spends all her time teaching and researching, it's up to her students to go find a use for the stuff in the world. (at least that's a kind-of defensible position, and the view I'll take just now)
So perhaps the question should be: first, understand the algebra of quantum interactions (von Neumann algebra); then, look for things in the world which behave this way. Instead of "Who else has already done this work?"
That said, one example that's tantalised me for a few years is V Danilov & A Lambert-Mogiliansky's use of von Neumann algebra in decision theory. Explicitly it is not about "quantum mechanics in the brain". Rather that "interfering (mental) states" might be a more accurate explanation of consumer behaviour than the usual picture:
Comment: @Stats It goes to the essence of the question, which is about *applications*, hence the *meaning* of non-standard probabilities.  (Von Neumann algebras lead ineluctably to complex-valued quantities that ultimately combine to produce probabilities.)
Comment: I don't understand how this answers the question at all.


Will an 11W UVC lamp kill bacteria?

Question: If I shone a UVC lamp (11W) on something (say for example a plastic phone case) for an hour, would that kill off a noticeable amount of bacteria? That is, if I were to go over the case with a cotton swab before the hour and swipe the cotton swab over a petri dish with nutrients and if I were to do the same after the hour with a different cotton swab and a different petri dish. Do you think that after a week there would be a noticeable difference in bacterial growth between the dishes? I think it should, since some filters for ponds work the same way, but I'm not sure, since in my case, the light needs to penetrate about 10 inches of air first and the environment isn't as closed off. What are your ideas on this?
Comment: I think you should add distance parameter to it because it has inverse relation with any rays that use for such uses
Answer: Some physical methods of sterilisation are in hospitals

Steam autoclaving
Dry heat – thermostat
White light / UV light sterilization

where continuous UV light has poor penetration.
UV radiation heat is absorbed by proteins and nucleic acid.
All micro-organisms contain tehm.
They inactivate the DNA.
There will be electronic and photochemical reactions by

photolysis
loss of colony-forming ability
enzyme inactivation
destruction of nucleic acid.

If I shone a UVC lamp (11W) on something (say for example a plastic
  phone case) for an hour, would that kill off a noticeable amount of
  bacteria?

Direct answer: Not all bacteria, but some.
UV light has poor penetration so it will not expose all bacteria.
Most prevalent bacteria there

streptococci,
staphylococci and
some others.

I estimate that the majority of the bacteria will remain because the light cannot reach each corner of the object.
In clinics, many hours and high temperatures are used to kill bacteria.
UV light is not efficient there.
I think the problem is that you cannot reach each corner of the object.
The high temperature and disinfectants can then again reach the clinical instruments throughly.
Manual work is however still needed.
You can then take examples of bacteria.
Search their corresponding temperature ranges.
The survival can also be dependent on the nature of the light of the bulb.
Each bacteria has an individual structure.
We can manipulate the environment to make bacteria more vulnerable to the heating i.e. to change the structure of the bacteria.
We can increase the duration of the heat exposure to make kill of the bacteria more effective.

Will an 11W UVC lamp kill bacteria?


Why do high voltage power lines hiss when it's raining?

Question: I noticed when walking home the other day that the high voltage (200kv I believe) lines running through here were hissing in the rain. What is causing them to hiss?
Comment: @Matt As an electronics *and* bird enthusiast, I'll comment that birds do, in fact, have tough feet. Their [corneum](http://en.wikipedia.org/wiki/Bird_anatomy#Scales) is the outermost layer of skin; keratinous scales. It's worth noting that birds will avoid high voltage lines when they are uncomfortable due to temperature, electric field, etc. Some birds can sense direction magnetically ([magnetoception](http://en.wikipedia.org/wiki/Magnetoception#In_homing_pigeons)), and HV lines likely disturb this sense.
Comment: Buzz or *tssss*?  The lines are usually quite warm, so they might rapidly evaporate the water that falls on them.
Comment: You're right, it was more of a 'hissing'. Edited
Comment: those birds must have some tough feet then
Comment: are these the big bad cross-country lines? how many conductors?
Comment: They do? I never noticed.
Comment: @JustJeff, 4 conductors on one side (I'm assuming 3 phase + 1 neutral), two conductors on the other side, 3 tiers of them.
Comment: i was just wondering whether it was a DC or an AC line and thought the number of conductors might be the best indicator. sounds like almost certainly AC.
Comment: Just as an aside, I discovered that walking underneath these powerlines in a decent enough rainstorm with a metal handled umbrella caused a noticable shock in the hand. Kind of like a static shock that you'd get on a dry day walking on a carpet with sock feet, but constant. I assume this is because the water droplets that fall from the lines at the right part of the cycle could be charged to 200kv.
Answer: High-voltage partial discharges across the insulators.
Comment: I'm not going to upvote an answer consisting of only 7 words, however correct. A bit more explanation would be welcome.
Comment: http://en.wikipedia.org/wiki/Partial_discharge ?
Comment: What is a partial discharge?
Comment: @Nick T - nice link!
Comment: OP didn't say the hiss was only at the insulators. If these are high-voltage power lines, the cables themselves wouldn't be insulated. Also, I'd expect powerlines to be designed not to have PD issues. From the same article: "PD prevention and detection are essential to ensure reliable, long-term operation of high voltage equipment used by electric power utilities."
Answer: I was taught that this is due to the Corona effect.  Basically, the power lines ionize the air around them, causing audible hum, along with havoc in the EM spectrum.  This is why really high voltage lines and transformers will sometimes have a slight aura around them.
Generally, the effect is undesired, because it robs the transmission lines of energy (the hum/light/heat dissipates energy), so a lot of equipment is manufactured to try and stop this effect.
The Wikipedia article will do this subject much more justice than I can.
Comment: I seem to recall that it was more likely in humid air, but I'm not particularly sure.
Comment: If it's due to this, wouldn't I hear the hum/buzz whether it was raining or not?
Answer: Good stuff in the answers so far, but I work with power lines and want to put in my two cents.
This isn't technically a partial discharge; occasionally you may be hearing the crackle of what is usually called a corona discharge. I admit the phenomenon is related, but it is not the same.
See, all uninsulated lines show corona. Its just not a big deal until you're dealing with a pretty high voltage. As the voltage goes from a very big positive to a very big negative, the air around it gets ionized, so about 50 or 60 times a second, it switches direction. This is the normal mains hum discussed in another answer.
Water is much, much heavier than air, and it ionizes just as easily. So on a rainy or humid day, the corona is pulsing with water in it. This gives it momentum, so the heavier water particles travel out farther. But they themselves are ionized, which means they can ionize more air than the line could normally reach on its own, and ionized air is conductive.
And there's almost always 3 of these lines pretty close together. The sound you're hearing is a million teeny tiny electrostatic discharges from all the charged up water particles interacting with each other with nearby lines or grounded objects. This is actually the worst time to be anywhere near them; the air is supposed to be their insulator,  and at that moment it isn't working as well.
Occasionally you might see a full corona discharging with the naked eye; it looks like a tiny bit of lighting crawling up the line. If it gets really bad, you'll see a momentary line to line or line to ground short, which looks exactly like a real lighting bolt, just not from the sky.
Answer: They'll actually do it when it's not raining too.  It's called mains hum.  Power lines carry AC voltage at either 50 or 60 Hz which is at the low end of the audible range of most humans.  In the presence of an electromagnetic field (like the one generated by AC power), the molecules of ferromagnetic materials (the metallic conductors inside of power lines) will not only try and align themselves with the field but sometimes change or distort their shape if the applied potential is strong enough.  This alignment/change in shape can cause collisions between the molecules comprising the power-lines which, given enough of them, can be heard by an observer.
Comment: ...but if it gets annoying, you could just think of it as a million electrons clapping their hands & cheering you on in your journey home
Comment: as per my comment to mjcarroll, why do I hear the hum/buzz only when it's raining?
Comment: @pfyon - I might guess that though rain makes some noise it also drowns out much more ambient noise such as rustling leaves or tall grass by weighing down and suppressing otherwise noisy things.  A sound of a bunch of dry leaves can integrate into one loud ambient noise.  I go hiking on the Appalachian Trail and there is always one spot that we go under power lines and I can hear them even when it's not raining.  Also, when it rains, the air is more saturated with water vapor (making it less of an empty vacuum) and can most likely carry sound further.
Answer: My wild guess would be that the hanging water droplets might be causing corona discharges. Corona is usually worst around points of sharper curvature, where the electric field gradient is most intense. Higher voltages, like the 200kV you mention, would make this more pronounced.
Comment: You beat me to it by one minute.  Cheers.
Answer: There are several causes but the most common is high voltage discharge along surface contamination on the insulators. This has a characteristic "hissing" noise, whereas most other phenonomon generate noise primarily at the line frequency or 2nd harmonic.
During dry weather dust builds up on insulators and it always contains some quantity of salt. When weather gets damp, enough water gets into the mix to allow it to become conductive, so small quantities of current start flowing. Once that happens any organics in the current path quickly become carbonised and the arc becomes more-or-less permanent (heavy rain will wash the insulators clean and the cycle then starts again)
The noise peak for hissing discharges is ultrasonic, so detecting where the actual arc is located is done using a small parabolic microphone with a viewfinder. (see http://www.arrl.org/files/file/Technology/PLN/Ultrasonic_Pinpointer.pdf for an example)
The hissing you hear is the least of it. Radio hams HATE arcs because they generate a lot of radio interference - so they tend to be the most enthusiastic purchasers/builders of ultrasonic arc locators.
Dust buildup is the primary reason why high voltage insulators aren't smooth - the typical "stack of discs" design makes it very hard for enough dust to build up to let current flow under damp conditions, so dust-based arcing is usually found only on 11kV or lower tension poles, where the insulators are a much simpler design.
Corona effects are usually only found on very high voltage lines (over 220kV)


Why doesn't the Tsetse fly wipe out all animal life in its range?

Question: The Tsetse fly, which is native to interior West Africa, carries the protozoan that causes sleeping sickness, a disease which was apparently invariably fatal before the advent of modern medications. Since there is no way to prevent being bitten by this insect, why did it not kill off all animal life in its range?
Answer: Firstly, as Remi.b points out, although Trypanosoma brucei infection is invariably fatal in humans, the same is not true for all host species. Domestic animals, particularly cattle, are an important reservoir of T. brucei rhodesiense and can also be infected with T. brucei gambiense (although it's not clear how important a reservoir they are for gambiense).
Secondly, just because all hosts in an area get bitten by tsetse does not mean they all become infected with trypanosomes. Even in endemic areas most vectors never become infectious. The transmission cycle for trypanosomes and other insect-borne pathogens requires an incubation period in the insect vector which is often longer than the median lifespan of the insect, so even if all insects get infected early in life, most will never survive the incubation period to become infectious. The later the average time of first infection gets, the higher the fraction of hosts that will have the opportunity to reproduce before dying.
Finally, it isn't entirely accurate to say "there is no way to prevent being bitten"; it is possible to reduce exposure to insects behaviourally. For example, in most endemic areas local residents will know which areas are most heavily infested and should be avoided.
Comment: Good answer +1. I think I've upvoted all of your answers so far! It is good to have you on Biology.SE.
Comment: Thank you very much! I only discovered the site recently but it seems to be a great community.
Answer: Trypanosoma, the parasitic protozoans that uses the TseTse fly as vector to reach its definitive host, a mammal. In wild mammals, Trypanosoma brucei has no noticeable impact (Chatterjee, 2009). I don't know about Trypanosoma cruzi.
Parasite who recently transferred from one host to another are often the most virulent. In the particular case of a parasite that transfer from an animal species to humans is called zoonosis. Ebola virus disease, AIDS, salmonellosis and influenza are all examples of zoonosis. I know little about Trypanosoma evolution but this lab probably have a number of publication that will interest you


Change site url when moving site to another url?

Question: Is it really neccessary to put WP_HOME, WP_SITEURL in wp-config.php or set these settings via admin panel every time when moving a WordPress instance to another url (for example: moving from dev environment to production)? Is there any better strategy?
Answer: Those parameters and admin settings change the URLs in the database. The only other way to do that is run SQL queries on the DB in phpmyadmin to change them:
UPDATE wp_options SET option_value = replace(option_value, 'http://olddomain.com', 'http://newdomain.com') WHERE option_name = 'home' OR option_name = 'siteurl';

UPDATE wp_posts SET guid = replace(guid, 'http://olddomain.com','http://newdomain.com');

UPDATE wp_posts SET post_content = replace(post_content, 'http://olddomain.com', 'http://newdomain.com');

UPDATE wp_postmeta SET meta_value = replace(meta_value, 'http://olddomain.com', 'http://newdomain.com');

Update 1/16/2015: it's much better to use a script that deals with serialized data, such as interconnectit.com WordPress Serialized PHP Search Replace Tool
Update 9/15/2023 Even better to use WP CLI: https://developer.wordpress.org/cli/commands/search-replace/
Comment: You should be careful with this approach because some plugins store serialized arrays in wp_options (like ContactForm7) and a brute replace (unless both domains have the exact same number of characters) may brake the plugin configuration.
Comment: These queries correctly find/replace in serialized data and don't break the plugin or the data.
Comment: Not if you have a serialized array in a meta_value in wp_postmeta, and that array contains the site url (if old and new urls have different str_len, of course)
Comment: @MZAweb: You're right, my mistake; update added.
Answer: What I do here is I keep an entry in my /etc/hosts file pointing the site domain to 127.0.0.1. Most of the time the line is commented so my machine points to the production site, and when I'm developing something I just uncomment the line and the domain will point to my dev box.
I know it's kinda ugly, but since Wordpress puts the domain in a lot of fields in the database (especially if you need to work with real data in your development environment), it's the fastest method I could come up with.
Answer: When you move from one server to another the problem could be URLs that WP serialized in DB.
To do a safe search and replace you can use this tool search replace db.
Is very simple, follow the instructions and remember to remove the script when done.
Answer: You could put those settings in an external file and exclude it from your publishing process.
Answer: I don't mess with core files, I just move the themes and plugins around instead. I develop locally and zip the themes and plugins for production. I have about ten WordPress installs most internal and this has worked well for me so far.
I also, don't move much data around so this answer may not help you. There are some pretty extensive free plugins for backing up data and restoring.
Answer: Use on the top of your functions.php:
update_option('siteurl','http://yoursite.com');
update_option('home','http://yoursite.com');
Navgigate through your site a bit, login the backend en remove these lines.
This should be sufficient.