How can I break up a lengthy explanation?

Question: I have a setting in one of my stories where a character has to describe a very long series of events, giving the history of an object so that others know more about it. This not only provides the reader with the background information they need, but also sets up other characters in the scene for something major that is yet to come. What can I do to break up this back story to keep it from becoming a long, rambling speech?
Answer: It sounds like you're describing an infodump (warning: TV Tropes), and that's a phenomenon best avoided.
The issue is this: by your own description, the explanation is not interesting enough to hold the reader's attention at length; its purpose and significance will only be clear to the reader later in the story; and in this particular instance, it's also long. You can see why this doesn't make for a great reader experience. It's as though you've got a brilliant, hilarious joke, that only makes sense if you read the first 3 pages of the phone book - and you can't tell your friends why they need to read the pages until they're already through them.
Here's the key: Avoid writing scenes which the reader has no immediate, compelling reason to  want to read. So if you're determined to write up a history lesson, you'd damn well better make sure that, at that point, the reader is dying to hear that lecture. Your other main option is to avoid the lecture entirely by conveying the backstory in other, more compelling ways, usually intertwined with the story and the action. I'll touch on both these options.
Prepping the reader for exposition
The idea here is to give the reader a strong interest in the details you want to expose. Then they're perfectly happy to listen attentively - they know exactly why they should be interested.

Mysteries of all stripes are based heavily on this approach - solving the case provides a tremendous incentive for the reader to sit through any length of otherwise-dull exposition.
Sometimes you can make the lecturing character play hard-to-get - basically setting up his information as being hugely important, refusing to reveal it, etc. If you manage this effectively, such a ploy can convince the reader of the exposition's importance.
The interest doesn't necessarily have to be plot-related or functional - if the details are charming, lyrical, amusing, controversial, etc., that's often enough to maintain the reader's interest and give him a justification for the piece.

In The Matrix, Morpheus explains to Neo what the Matrix is. This is straight-out exposition and backstory, but it's one of the coolest, most memorable scenes in the movie. Observe how well the movie establishes that this infodump will solve a question we want answered ("What is the Matrix?"), and that this question is crucially important and monumental (observe all the effort and intrigue and escapades that all sides expended to get Neo this information or to keep it from him). The scene itself is also beautifully presented - Morpheus doesn't just explain; he demonstrates, he brings in cool, colorful stuff, he makes the explanation fast-paced and action-like even when there's nothing actually going on.
One proviso is this: differentiate between the reader's interest in the exposition, and a character's interest. For example, you might have a pupil-mentor dynamic between two characters, with the pupil desperately eager to win the mentor's respect by learning well. The reader will be invested in the pupil's goal - but that goal is pleasing the mentor, not learning the material. That's the means; the details themselves don't interest the reader. If you want the reader invested in the details, then you've got to give him a reason to care about them.
Weaving exposition into plot
The Turkey City Lexicon refers to this as "Heinleining." The idea is that you avoid the need for a long lecture, by having the details you want to expose show up as significant details in the plot without ever stopping the action. How do you do this? Well, if the details are really that significant, unique, and world-changing, then they probably affect the world in more ways than one. If the Goddess Fifthemia is locked in eternal conflict with the Thermal Demigod Extrynius, then that might well have resulted in the Mythaline Cult creating the Gem of Hypothermia, which is the focus of your story - but probably some other people have noticed and been affected by the issue too, hmmm? So you could portray Fifthemites being bigoted against Extryites, or one of the characters could be an atheist whose farm is declared as holy ground by both gods, and he needs to decide which priest to sell it to. And those are scenes which justify exposition immediately, as you go along - often, trickled in bit by bit, so the reader doesn't even notice he's being exposed to.

Whichever option you choose, I think you'll have found the answer to your question, because the explanation will no longer be a monologue that needs to be broken up into pieces. It will be a scene, with conflict and emotion and goals and reaction; those are constantly present and keep the explanation from turning into a lecture. As a scene, intertwined into the larger story, it might also be taking place in the middle of some larger event - in the middle of a battlefield or a football game or a demonic convent or a snowy hidey-hole in which the characters are waiting for Santa Claus, and all those also serve to keep the explanation from becoming monotonous.
Bottom line: the best way to avoid boring the reader is to write scenes, not explanations. The good part of this is that, with a bit of planning and creativity, explanations can be made part of scenes - and twisted into something much more interesting and compelling than they could ever be on their own.
Comment: @michael I'm still there!
Comment: @NeilFein Did you ever recover?
Comment: Great answer. But I read it an hour ago, and I'm still sidetracked on TV tropes.
Answer: Interrupt the character.
Have you read The Hobbit? Gandalf had to make a lengthy explanation, which he didn't want to get boring, so he set up the dwarves and Bilbo to interrupt him from time to time. From a cat flashing by to another character getting in, there is much you can do.
Having the character unwilling to talk, but being coaxed into telling the story little by little is another way to achieve this.
Comment: This is generally a good way to handle this, but (I'm sorry to say) in Lord of the Rings, this doesn't always work.
Comment: Not Tolkien's explanations, those tend to be lengthy and trying, sometimes. But Gandalf's was interesting... So my take was to do what Gandalf did, and apply to the reader.
Answer: Phil Farrand of The Nitpicker's Guide to Star Trek called this "being the cabbagehead." Certain information had to be revealed to the audience, but it was information which the characters would reasonably already know.
So the writers picked someone in the room to be the "cabbagehead," meaning someone developed the I.Q. of a cabbage and everything had to be explained to him or her as though s/he had never gone through Starfleet training and years of spaceflight experience. (Counselor Troi got this role a lot on TNG.)
Practically speaking, you set things up so one or more of your characters is woefully uninformed about whatever it is, and the more informed character(s) have to enlighten the cabbageheads. As far as technique, Kate and iajrz both have excellent suggestions.
Comment: It was artificial in Trek, to be certain. But if you've structured your story correctly, it doesn't have to be. In fact, in your excellent answer, Neo IS the cabbagehead in that scene. It's not Neo's fault; that's just how his life is. That's what I was referring to. For the actual scene of explanation, Kate and iajrz have the right idea.
Comment: This example fits perfectly for my story. There is one new character who has not been exposed to any of the history, while others have. Thanks!
Comment: Having somebody "be the cabbagehead" is _not_ a good thing. As you describe, it's very artificial, and instead of making the infodump interesting and palatable, it merely provides an excuse to deliver it dryly.
Comment: It would work well if you can have it be a discussion, rather than pure exposition.  Perhaps if two or more characters get together to drive the knowledge dump, with each having only part of the whole back story?  Remember to have parts that they get to disagree on, and you can you can let the snarky comments flow and flesh out the characters some as well.
Answer: Are you planning to use dialogue or narrative for the description?
If dialogue, and assuming that you've been careful to avoid the 'he exposited' syndrome, in which one character tells another character something that they both know very well as an awkward way for the author to get the information across... I'd try to break up the speech with reactions from others.  We have to assume they care about this, right?  So have them be involved.  They can ask questions, make comments, react emotionally, etc.
If you're planning to use narrative... I'd try to break it up if possible, to avoid having an info. dump, but I truly believe there are times when you've just got to get the information out there, and sometimes dumping it is the only way.  But if possible, you could give us the information in little bits, only as needed. Or you could bring in some dialogue or characterization to help break it up.
Answer: If the explanation is interesting, the reader will not notice that is is long. If it is not interesting, breaking it up will not make it interesting.
So forget about whether it is too long and focus on whether or not it is interesting. The reader may be interested in explanation for one of three reasons:

They are interested in the thing being explained. When you explain weapons in a thriller or forensic procedure in a mystery, many readers will be interested in these things independent of their role in the story.
They are interested because the explanation is so gripping that it creates interest simply because it is so good.
They are interested because the explanation makes the story make sense.

It is important to get the order of things right with these. You may want to give an explanation up front in order to make the story make sense when the reader gets to it. This is not a case of number 3. For number 3 to apply, the reader has to already be in the story and sufficiently committed to it that they are hungry for the explanation so that they can go on with the story. If you want the explanation to come before the story, then you have to make it either number 1 or number 2.
Number 1 requires knowing your audience and knowing your stuff.
Number 2 requires being a genius.
Comment: And -- it seems to me -- number 3 requires writing a story that is so delicately cut that cutting out anything more makes at least a part of the story incomprehensible. In other words, every word serving a purpose.
Answer: first off, i have two words...small sentences.  these provide dramatic effect and engage the reader.  on top of that, it's helpful if another character interrupts to ask questions or comment. then you can show how the two are reacting to the story as well as explaining what the reader needs to know.
Answer: I'd suggest avoiding lengthy backstory details. Provide just the minimum you have to, and break up the description with dialog and small bits of action. Perhaps allow the description to take place over multiple scenes.
Answer: Maybe you could go back in time for a chapter or prelude and tell this object's story from a tense that is closer to the important part of it's history. Then when it comes time for the character to describe the history of the object, the reader already knows the story and you can just skip over the part where this character is doing the explaining ("He explained to them the story of the _").
Answer: You could try to disguise the infodump as something else. As it starts, cut to a flashback portraying the events in a more immediate sense. You could also choose to have the actual explanation going on while other events are happening, intercutting them at regular intervals (preferrably dramatically ironic ones).


How can I root my Samsung Infuse 4G (AT&T)?

Question: I have been looking everywhere online, but I cannot find anything helpful in rooting my Samsung Infuse 4G. I have even tried (once) with SuperOneClick, but it never worked. Didn't affect my phone, but it did lock my pc up for a bit. Does anyone have any helpful advice?
Answer: Rooting a phone generally does not affect it visibly much, other than a new "Superuser" app in the app drawer.  Rooting only provides ability to gain elevated privileges, with the Superuser app acting like the gatekeeper for other apps requesting such privileges.
SuperOneClick is the preferred method for rooting the Infuse 4G.  If you're unsure if that succeeded, here's what you can try to check if your phone was indeed rooted:

From the Market install the Terminal Emulator app.
Launch the app, and using the on-screen keyboard type in su and press Enter.
If your phone is rooted, a new dialog named "Superuser Request" should come up. Tap the "Allow" button.
You should see a pound sign #. Now type in reboot and press Enter.

If at this point your phone reboots, you have root.  Otherwise you will receive the following message "reboot: Operation not permitted"  This means the rooting did not complete successfully and you may want to re-try it by following any of many guides found online.
P.S. Please be sure to follow the guide designed for your specific device.  Not all Infuses are the same - there are differences between the AT&T version and Rogers', for example.


Why isn't there a uniform probability distribution over the positive real numbers?

Question: Apparently, the solution to the Card Doubling Paradox is that a uniform probability distribution over the positive real numbers doesn't exist. Can anyone explain why this is the case and what probability distributions can exist over the positive real numbers (it seems that this would be quite limited, given that such a simple distribution is impossible)?
Comment: [This](http://math.stackexchange.com/questions/14167/newbie-probability-question/14169) may be of help.
Answer: If a uniform probability distribution did exist, then for any integer $n$ the probability a real number $x$ satisfies $n \leq x < n+1$ would have to be the same for all $n$. Call this probability $p$.
One of the rules that a probability distribution has to satisfy is that if $\{E_n\}$ are a countably infinite collection of disjoint events then $P(\cup_n E_n) = \sum_n P(E_n)$. Let $E_n$ be the event "the real number $x$ satisfies $n \leq x < n+1$". Since every real number is between some $n$ and $n + 1$, $P(\cup_n E_n) = 1$. On the other hand, $\sum_n P(E_n) = p + p + p + ....$. If $p > 0$, this gives infinity. If $p = 0$ it gives zero. In either case, you'll never add up to $1$. Hence you cannot have a uniform probability distribution over the reals.
Comment: The Lebesgue measure of $\mathbb{R}$ is $\infty$, not 1 as we would want for probabilities to make sense. This is the root of the problem in defining uniform distribution over $\mathbb{R}$.
Answer: A uniform probability over the positive real numbers would not satisfy all three axioms of probability. Specifically, there is a conflict between the second axiom ($P(\Omega) = 1$) and the third axiom (countable additivity).
Check out the wikipedia entry http://en.wikipedia.org/wiki/Axioms_of_probability. I think it should be clear how a uniform probability over the positive reals would cause problems.
Answer: For every probability density $f$, $\liminf_{x\to \pm \infty} f(x) = 0$ must hold.
It is clear that for a uniform distribution, the density has to be constant on the considered interval.
Combining both requirements, only $g(x) = 0$ remains as a choice for a uniform density on $(-\infty, \infty)$. But $\int_{-\infty}^\infty g(x)dx = 0 \neq 1$, that is $g$ is no proper probability density.
Answer: "Uniform probability distribution" always refers to a pre-existent natural measure on a space with a transitive group of "translations", so that any two points resp. neighbourhoods of two points are comparable which each other. The simplest space of this sort would be the set $\mathbb Z$ of integers, and already there the problem you address becomes manifest. Of course it is easy to prove that there doesn't exist a uniform probability distribution on $\mathbb Z$; but you want an intuitive reasoning. While it is easy to come up with a random mechanism that selects any number between $-10^6$ and $10^6$ with equal probability, it is just unimaginable to fathom a mechanism that selects 5 with the same probability as any power of the prime with number $67212345$.
Answer: The problem stems from measure theory.  Let $V^1, V^2, V^3, ...$ be a sequence of Vitali sets such that the collection $\{V^n : n \in \mathbb{N}\}$ partitions $[ \,0, 1) \,$.
It is then possible to create a mapping $k$ from each set $V^n$ onto $n$ such that $( \,\forall x \in V^n)\,(\,k(x) = n) \,$).  An example of this is described in detail here:
Is this fraction undefined? Infinite Probability Question.
At this point, it's easy to see that if $a, b \in \mathbb{N}$ and $x$ is selected uniformly at random from $[ \,0, 1) \,$, then the probability that $x$ will fall in $V^a$ is the same as that of $x$ falling in $V^b$. There is one problem, however, in that these probabilities are undefined.
This is because Vitali sets are non-measurable.  If they had a positive real measure, then the sum of their probabilities in this case would be infinite.  If they had a $0$ measure, then their sum would be $0$.  We are left with no definable cumulative distribution function over the naturals.
Given the above clarification, we could use the above model to select a real in $\mathbb{R}$ such that all real numbers have an equal, but undefined, probability of being selected:
1) Let $f : \mathbb{N} \rightarrow \mathbb{Z}$ be bijective.
2) Let $x, y$ be selected uniformly at random from $[ \,0, 1) \,$.
3) We then have $r = f(k(x)) + y$.


Why does Account Controls not work on the Ardor parent chain but only for child chains?

Question: Account controls that let you do account locking doesnt seem to show up on the Ardor parent chain. Why is this disabled while it works for the child chains? How does one secure their Ardor, if account control doesn't work.
Answer: According to NXT wiki:

In Ardor, only child chain transactions can be phased. Therefore, when account control is set for an account, it can no longer submit Ardor chain transactions.

In other words: account locked for child chain is locked for Ardor chain to.
See for details: Account_Control
Comment: Looks like you can't do anything, even leasing. For being unable to send Ardor - wasn't this the purpose of "securing their Ardor"?
Comment: if i can't submit ardor chain transactions. does that mean i can't do anything on the Ardor parent chain anymore? Even leasing? Or sending of Ardor to another account?


Why is the simulation required in these identity-based encryption security proofs?

Question: In identity-based encryption papers (i.e.this) it is very difficult for me to understand security proof. I don't know why they prove assumption (BDH, BDDH) for security of their scheme. Some uses random oracle and most of them try to simulate the scheme. Why is the simulation required in these security proofs?
Answer: (I assume you are asking about this paper based on your previous questions.)
They do not prove BDDH in their security proofs.

Assume that an attacker $A$ breaks IND-sMID-CPA of the above scheme
  with probability greater than $\epsilon$ within time $t$ [...]. We show that using $A$, one can construct an attacker $B$ for solving the
  BDDH problem.

In security proofs by reduction, we assume the proposition is not true (here: assume the proposed scheme is not IND-sMID-CPA) and show the proposition being false would imply some contradiction (here: solving BDDH problem which is believed to be hard). In this case assuming existence of attacker $A$ against IND-sMID-CPA security of the proposed scheme, they construct algorithm $B$ for solving the BDDH problem. Attacker $A$ is expected to participate in IND-sMID-CPA experiment, so through the reduction algorithm $B$ should simulate the experiment for $A$ and since this proof is in the random oracle model, $B$ should simulate random oracle as well.

problem B is reducible to problem A if an algorithm for solving problem A efficiently (we call this algorithm $A$) (if it existed) could also be used as a subroutine to solve problem B efficiently.

In this context:
A = breaking IND-sMID-CPA
B = BDDH problem
reduction algorithm $B$ uses adversary $A$ as a subroutine. $B$ doesn't know how $A$ works; the only thing $B$ knows is that $A$ is expecting to attack problem A. so given an input instance of problem B (here BDDH), reduction algorithm should generate (simulate) an instance of problem A for $A$.
Chapter 3.3.2 of Introduction to Modern Cryptography explains "proofs by redcution".
Comment: @LaYateMay being unfamiliar with nature of security proofs causes hard time reading cryptographic papers. Maybe [this presentation -p16-20](http://www.cs.bris.ac.uk/Research/CryptographySecurity/SummerSchool2009/slides/Alex.pdf) could help you (I am looking for more sources which may help you).
Comment: @LaYateMay I edited my answer, I think chapter 3.3.2 of the referenced book is a great source.
Comment: @Mhy.Why $B$ construct simulation for $A$? If random oracle model is used,simulation is required? How to know the scheme needs to use random oracle model? May be I don't know nature of security proofs by reduction.
Comment: In normal security proof, just challenger and adversary. In security reduction proof, two adversary, $A$ and $B$ algorithms.If $A$ succeeds in breaking security, then $B$ is also sure to break the security. If so?
Comment: @LaYateMay Simulation is generally required (not only in random oracle model).
Comment: @Mhy.So many thanks to you. I will try reading your references.
Comment: For this one, [3]: https://www.crcpress.com/Introduction-to-Modern-Cryptography-Second-Edition/Katz-Lindell/p/book/9781466570269, as it is not free.
Comment: Let us [continue this discussion in chat](http://chat.stackexchange.com/rooms/42487/discussion-between-la-yate-may-and-mhy).


XJC Generating same classes

Question: I'm using JAXB on two different XSDs. Some of the generated classes appear to be the same. Is this unusual, and when I copy the classes over to my source package structure, should I just copy over the duplicate classes?
Or, is it possible to run xjc with a flag that says not to copy over/generate duplicate classes?
Answer: It's the episodes feature you are after.
This post on SO might help, along with this; the latter might be a bit outdated, but I've seen people asking questions on SO about issues long solved in newer versions of JAXB, so one never knows...

XJC Generating same classes


In episode 13, what piece does Kousei play after he plays Liebesleid?

Question: In episode 13, after Kousei played Love's Sorrow, he played this one song on the piano. What is the name of that song? I've been looking for it for the past four hours, but haven't been able to find it.
Answer: I'm assuming you're referring to the piece Kousei plays at the very end of the episode; this is the only instance where Kousei plays the piano in ep. 13 after his "Liebesleid" performance. I recognised this as a Chopin composition, possibly a nocturne.
After some searching, I found that this was Nocturne no. 2 in D-flat minor, op. 27. (Score, recording by Eric Lu at the 2015 Chopin Competition.) It should be relatively easy to recognise the piece if you have some prior familiarity with it, since Kousei starts playing at the very beginning.

Originally, I wondered if some other piece (such as "Liebesfreud", which is named in another answer as the piece Kousei plays) might have crept into the soundtrack at some point, perhaps in a flashback or in Kousei's reflections. However, after listening carefully to the soundtrack and checking the "Liebesleid" score and some recordings, I've confirmed that everything we hear during the performance segment is from Rachmaninoff's "Liebesleid". Thus, the only music for piano that we hear being played in this episode is "Liebesleid" and the Chopin nocturne.
Note that what viewers hear is a modified, lengthened version of the Rachmaninoff arrangment. (The soundtrack returns to the beginning of the piece right before the first key change, when we see Kousei underwater. This jump does not exist in the original score. There are similar jumps later, during the flashback with Saki after Kousei has lashed out at her, and when Saki reflects on Kousei.)
Answer: That is Sergei Rachmaninoff - Liebesfreud(Kreisler, arr. Rachmaninov).
Comment: I have removed a link i believe leads to an site that allows illegal download ingof music as i can search for Gangnam Style from Psy and download it for free and not seeing how Psy is being reimbursed by this when the App Store would charge me to download it
Comment: Liebesfreud never appears in the episode in question. Moreover, the only instance where Kousei plays the piano _after_ playing Liebesleid is when he plays the Chopin that I mention in my answer, and at that point, he plays enough of it that it should be fairly recognisable to someone who knows the piece.


Offered a job and now references are being asked for, the potential employer doesn't know that I failed probation at my last role, what do I do?

Question: I said that I left the last role (on the advice of my universities career advice service). I was indeed thinking about leaving but was actually informed that I had failed my probation period before it was over. This was all mainly due to suffering from depression which I have informed the potential employer of. I never explicitly lied about whether I was let go at the last role (and wouldn't) but how much effect could this have now that the potential employer is looking for references and what can I do about it?
Comment: Your references do not have to all be from jobs. Since you are still a student, I would say it's acceptable to have a reference from your adviser or a professor or grad student you have worked closely with.
Comment: Normally you choose the references you give - do you have to refer them to the last employer?
Comment: @topomorto Ah OK, I have never had to give them before. I only have one other reference I might be able to give which was just for an internship. The last job was the only full time contracted position I have had.
Answer: Provide them with references from some other company.
Whether you quit, or were let go from your previous role, you were still only there for a very short time, and no reasonable person would expect you to have a reference available from them.
Answer: References are not usually about your competence on the job - that has already been determined at your interview.
When requesting references, I'm looking for confirmation that they did work where they claimed on their CV, do they turn up on time, have there been any conduct issues? What are there weak areas that need supporting?
The key phrase  "offer subject to satisfactory references" is typically used.  What this means is that your job offer will be pulled if they are unable to obtain references, or if references uncover something incompatible with working at your new company.
I have given a fair, but positive reference for someone who was sacked, that was well received by their new employer, likewise I have refused to give a reference for someone who had claimed to work for me, when in reality, we interviewed them, and rejected them at interview - with a strong suspicion at the time that their CV was bullshit.
Answer: Generally agree with @AndreiROM not to provide reference for the position where you failed probation. Although, it's unclear just how short your time in that role was? Probation typically lasts 6mo-1yr. This may be considered adequate for a reference, especially in this case, where the only previous job was a an internship...
So this is not as clear-cut given lack of prior work experience. What is probably certain is that a reference from the position from which you were let go is not going to help your candidacy. Once we establish that, what other options are there?
Option 1: Give the internship reference only. You may have to explain why no reference from a more recent job is provided. Saying that you did not pass probation probably would be as bad as providing a reference that would say the same. The other option is to say that you do not consider time in that role sufficient for a reference to provide a fair assessment of your abilities. This may seem suspicious, but not overtly negative.
Option 2: Give the internship reference (assuming they have good things to say about your performance), AND a reference from your most recent job, for someone other than the individual who let you go. Was there someone else you worked with, who thought your performance was satisfactory? If so, tell them your thinking and ask them if they could serve as a reference. Hopefully they will understand the situation and be willing to put in a good word for you.
Option 3: Provide no references. If they press you for them, and say that references are required before your application can be considered, you can say that due to limited and brief work experience you simply do not have references at this early point in your career. Let them decide what to make of that and how to act on this. It is your right to refuse to provide any application document and to provide an explanation for your decision.
Option 4: Look for other positions, where references are not required. This may be necessary at this point since there is a chance this job might not work out due to the reference issue. Not all positions are equally bent on requiring references, and I am sure with enough perseverance you can find an employer that won't make this a sticking point.
The greater issue I see here is the depression itself. I hope you are on a path to healing, proactively tackling this condition, learning all you can about it, and seeking a long-term solution. This is not easy but this is probably the only way to ensure more stable, productive, successful career in the long term. Thank you for an honest question. Good luck!


Can I expect necessarily higher accuracy when feature selection/dimension reduction is used to select a subset of features?

Question: The feature selection/dimension reduction is performed to eliminate irrelevant or redundant features so it will improve the computation efficiency (less computationally expensive). My question is that can we expect any changes in the accuracy of prediction when efficient features are used for classification vs when all features used?
Answer: Using all features would usually lead to over-fitting, that is your model would not generalise well to unseen data. To overcome this, while using as much information possible we resort to feature selection ( sometimes feature generation ), and dimensionality reduction. Dimensionality reduction techniques like Principal Component Analysis (PCA) tries to find new features that explain maximum variability in data, using the existing features. In this way, we ideally reduce the number of features in the model, while making sure most of the variability is explained.
So as a result:

This new model is computationally faster since we are no longer using all the features and burdening our model.
Generalises well since we are not over-fitting leading to greater accuracy on unseen data.
Answer: It's a trade-off
Information is in the variance of data
Let's say, we have a dataset with very high dimensionality, definitely, it will create a problem for any model(may refer the logic behind Curse of Dimensionality)
- We lose some variance while reducing the dimension
 - We helped the model learning the data. There might be other underlying reasons too (than computation) i.e. removal of colinear and irrelevant features
 So, if the gain is more than the loss, then it will definitely improve the model's performance.
Though it was not your question but be mindful of the fact that with Feature engineering we also create some good Feature by doing an intelligent Exploratory data analysis
I made this point because with dataset not having too many Features(when not considered as very high dimensionality), Feature engineering is more about finding new useful feature using the info from the data and some real-world knowledge about the problem. Manytime, a simple transformation using some Heuristics also works(Kaggle kernels)


What happens to boiled pasta if you use too little water?

Question: There are almost always guidelines on pasta packages for the amount of water you should use when boiling.  Sometimes I'd like to use a pot that's on the smaller side, and that got me wondering; what actually happens to pasta if you use too little water (assuming it's at least fully submerged)?
Answer: See:

What is the correct water to pasta ratio?
How much water to put in my pasta pot?

Short answer:  if you stir once or twice at the beginning to prevent sticking, and all of the pasta is submerged, you can very successfully make pasta in a reasonably small quantity of water.
Here is a direct link to the Serious Eats article both of the answers above cite.
Answer: Anytime you boil a starchy food, like pasta or potatoes (or yuca :), some of the starch ends up in the water (or broth/stock) and thickens it a bit. Now when you're making a stew, you want that thickening to happen, so you use somewhat less liquid to pasta/potatoes. But generally when you're just making pasta alone, you want the pasta noodles to remain separate and you don't want any more thickening than necessary.
Also important is that if you're talking about dried pasta, the pasta needs sufficient water to rehydrate.
At the extreme, if you used just barely more water than pasta, the pasta would heat but never fully rehydrate and/or you'd end up with a sticky, underdone mass.
Comment: Actually, the Serious Eats article referenced in the accepted answer debunks most of your claims. The one about the starchier water ends up making no difference for cooking pasta, and proves to be even handier for use in thickening your sauce later.
Comment: Cute article. But it doesn't debunk anything I said. The author points out the increasing concentration of starch-in-water if you use less water. Whether starchy water is something desirable or not depends on the cook/sauce/application. And when he used the bare minimum of water, he did in fact have to stir the pot a fair bit, and check doneness frequently - not necessarily something everyone feels like/has time to do.
Comment: @MandisaW As you said: "At the extreme, if you used just barely more water than pasta, the pasta would heat but never fully rehydrate and/or you'd end up with a sticky, underdone mass." This was definitely debunked regardless whether you had to stir the pasta a lot or not. And this is the very extreme. If you cover your pasta with enough water, you only need to initially stir the pasta.
Comment: @MandisaW Fom my reading of the article (and from experience), pasta has to be stirred to begin with regardless of how much water is used.
Comment: @MandisaW The point is that you can use substantially less than is commonly used and everything will be fine. The starchy water gets poured down the drain. The question does say "assuming it's at least fully submerged", and as long as it is, it will cook fine.
Comment: I suppose this will be good news for people tightening their water budget then. As for me, I like fix-and-forget pasta, so I'll stick with my usual water:pasta ratio (not buckets, but not "barely submerged" either).
Comment: @MandisaW it's not only water that's wasted when you add more than needed, but energy wasted from unneeded heating to get a larger mass to boiling, as well as increased time waiting for the larger volume of water to boil.
Answer: One of the reasons for using lots of water to cook pasta is that the temperature of the boiling water does not drop drastically when adding the pasta when it is proportioned that way...the water will just keep boiling...or reboil very fast..
however, using little water for lots of pasta...will drop the water temperature too low and then takes longer time to reboil..the result is starchy, sticky, and  gummy pasta that was sitting in lukewarm water too long..
The standard for Chefs is one liter water (4Cups) per 100 g pasta (around 3 oz)...and of course salt..lots of room for the pasta not to be crowded..
Comment: Unfortunately, while I have no doubt about the standard practice, the science behind it has been debunked.  As [Kenji Alt has pointed out in his article on pasta](http://www.seriouseats.com/2010/05/how-to-cook-pasta-salt-water-boiling-tips-the-food-lab.html), has pointed out, the amount of energy required to bring water back up to temperature is not proportional to either the amount of water or its temperature before the pasta was added, but rather the volume of pasta and how much energy it absorbed.   See the link for more.


How do I restart Jetty on a Jenkins slave node?

Question: I am trying to deploy a .war on a Jenkins slave node that is running Jetty using an execute shell build step. To do this I am running the following in my shell command.

/etc/init.d/jetty restart

It starts Jetty successfully, but as soon as the Jenkins job finishes it stops. As I was trouble shooting this, I put a long sleep in the shell build step, and Jetty ran the entire time during the sleep, so I know it has something to do with exiting the shell after the job completes.
Is there any way to keep Jetty running after the shell exits in Jenkins?
I have tried using this but it doesn't do the trick.

nohup /etc/init.d/jetty restart &
Answer: its actually piss-poor-simple:
<code>echo "/etc/init.d/jetty restart"| at now
</code>


Making the ASK QUESTION more prominent c

Question:
For a site whole purpose in life is to allow people to ask questions and answer them, the new design does not make the two corresponding 'links' prominent at all!
Moreover, I really think it is quite not apparent that the "QUESTIONS TAGS USERS..." thingies under the header are active (you can hover over them, and then the thin font with which by browser renders then becomes #90191C: this is too subtle IMHO. Before it was way more obvious that something would happen upon clicking them: now, they look like a subtitle, specially because they match the all-caps style of the header (I guess one cannot assume real small caps are available?)
The votes/answer counts are horizontally distributed in the parent site and vertically distributed on the meta site, but this seems to change every few reloads. The effect is weird :) The ayout is vertical but different in the QUESTIONS and UNANSWERED pages.
Can it be ASK A QUESTION?
Comment: +1 for ASK A QUESTION.
Comment: I use stackexchange sites everyday, in this one I hanged on finding how to ask a question!
Answer: I support making "ask question" a different color.
However.
It's sort of a myth in the Q&A world that you want to make it so easy for newbies to ask questions. This logic leads directly to things like http://yahooanswerfail.com
What you do want to do is make it easy for people to browse around -- and they have to work a teeny-tiny bit to find out how to ask. If they're not willing to put in the tiniest amount of work, the odds of that user asking a question you as an expert would want to answer is vanishingly small.
Comment: This was going to be about the &c in the title, not the ASK QUESTION, but when I tried to ask this I could not find the link... I want it to be easy for *me*. YMMV.
Answer: I have bolded the Ask Question link, also gave it a different link color. The change will be in the next deployment.


Halachos of the bathroom

Question: Can someone give a rundown of the halachos of conducting one's self in the bathroom ( including how much one can remove his clothing ? )
Comment: Please clarify" how much one can remove his clothing " Many people use the bathroom for showering and (what a concept!) bathing, so they would be removing ALL of their clothes, I presume.
Comment: One item is that Shulchan Aruch mentions not to talk while addressing your "needs". It also mentions that men should not urinate while standing. (There's a separate M.Y. question that I asked a while ago regarding how men are allowed to use urinals.)
Answer: This is a good question. A good place to start would be to read the Kitzur Shulchan Aruch, Siman 4. If you have a Kleinman Edition Kitzur by ArtScroll, they have a brilliant linear translation method, and if you do not have a set you can purchase one here.
Siman 5 also provides loads of halachos about cleanliness, for further reading.
Here is a rundown of [some] of the halchos regarding composure and behavior in the bathroom. All of these halachos come from Siman 4 of the Kitzur Shulchan Aruch:

One should accustom himself to using the bathroom both in the evening and in the morning.
One should not hold back his bodily functions, as it transgresses the passuk "Do not make yourselves abominable." (Vayikra 20:25) Also, a man must not hold himself back from urinating because this transgresses the passuk "There shall be no sterile man among you." (Devarim 7:14)
A person must behave modestly in the bathroom by uncovering only what is necessary. A person has to be careful to do this in the night as well as the day.
One shouldn't relieve himself in front of any person, not even a idolater. But you can urinate in public if necessary, as to not hold yourself back from urinating, which is a transgression in itself (as explained before).
One shouldn't relieve himself while standing and shouldn't force himself to defecate by straining, because doing this might tear the muscles that hold the rectum.
One shouldn't hasten  to rush from the bathroom until he's sure he is finished with his business.
When urinating while standing, a man must be careful to not drip urine on his shoes or clothing, and he shouldn't hold his organ with his hands.
One cannot contemplate Torah thoughts in the bathroom. Instead, one should think about business matters, so he doesn't start thinking about Torah or sinful thoughts, Chas ve'Shalom. When one cannot think about business (like on Shabbos), he should think about the things he's seen or heard that's interesting.
One should wipe himself well after defecating, because if there is anything left behind in his rectum he cannot recite sacred words.
One shouldn't wipe himself with the right hand, because he uses it to tie tefillin on his left arm. In the same way he shouldn't use the middle finger on his left hand because this is the finger he wraps tefillin onto.
Every time one uses the bathroom, even just a small amount, he should recite the Asher Yatzar blessing. If he forgets to recite this blessing, he should recite it when he remembers, once, not twice. One who took a laxative (a pill that cleans one's bowels out) shouldn't recite Asher Yatzar until he is sure the laxative has completed its job.

Hope this helps. There are additional laws, but please read the links I provided if you want to learn more.
Comment: Importantly, one does not seem to be a halakha, three seems to be a middat hassidut, or proper non-halakhically mandated behaviour, four also seems more about probably variable) standards of modesty, than set formal halakha, five seems like a medical issue; consult your local doctor, six, seems like good advice, but not a halakha, one can debate whether the first part of seven still applies. ten seems like another middat hassidut, (that incidentally is likely not even relevant these days).
Comment: @mevaqesh - mevaqesh is at it again...picking apart my answer piece by piece! lol ;D i am just parroting what the kitzur says read the kitzur siman 4 and you'll see all the things i've stated. but truth be told, the kitzur doesn't just list halachos
Comment: `but truth be told, the kitzur doesn't just list halachos` Exactly!
Comment: I am glad you take my attention to detail as something amusing, and note that someone took the time to read and scrutinize your posts. Note also that as far as I am concerned, even if you would just cut out all the items I mentioned, this would still be a fine answer. It contains (IMHO) very useful information for answering the question. Hatslaha rabba continuing to provide appropriate answers, hazak hazak hazak!
Comment: I am touched by your kind words. However, I would personally remove the personal reference to another user in your precious comment. It is too late to edit you can delete and re post, with an eye to removing extraneous info an comments.
Comment: @mevaqesh - i'm glad you understood the first part of my comment to be humor. i actually am happy someone takes the time to read through everything and understand exactly what i am trying to say. thank you for the kind words. chazak chazak chazak to you as well.
Comment: @mevaqesh - changed accordingly
Comment: I dont have time to review it at the moment. B"h I will do so in the future.
Answer: Halachos of the Bathroom Written by Rabbi Moishe Dovid Lebovits of KOF-K Kosher Supervision  gives a summary of the halachos of the bathroom. However, it does not deal with the subject of removing ones clothing. The article is too big to summarize here and I do not have the time to add the halachose regarding clothing right now.
Have a good Shabbos

Halachos of the bathroom


Prove sequence converges uniformly

Question: Suppose that the sequence ${\rm f_{j}}\left(x\right)$ on the interval
$\left[0, 1\right]$ satisfies
$$
\left\vert\,{\rm f_{j}}\left(t\right) - {\rm f_{j}}\left(s\right)\,\right\vert
\leq \left\vert\,s - t\,\right\vert^{\,\alpha}
$$
for all $s, t \in \left[0,1\right]$, ${\rm j} = 0, 1, 2,\ldots$, and for some
$\alpha \in \left(0,1\right]$. Furthermore, assume that the sequence of functions ${\rm f_{j}}$ converge pointwise to a limit function ${\rm f}$ on $\left[0,1\right]$. Prove that the sequence converges uniformly.
Comment: I wrote an answer, but I would be surprised if this fact this hasn't been proven and given a name already, using the more general assumption that the sequence $(f_n)$ is equicontinuous.
Answer: Let $\epsilon > 0$.  Let $N \in \mathbb{N}^+$ be big enough so $(1/N)^\alpha < \epsilon/10$.  Let $M \in \mathbb{N}^+$ be big enough so
$$n \geq M \Rightarrow \max\{|f_n(0)-f(0)|,|f_n(1/N)-f(1/N)|,|f_n(2/N)-f(2/N)|,\ldots,|f_n(1)-f(1)|\} < \ldots $$
$$\ldots ...<\epsilon/10$$.  Applying the triangle inequality (similar to the way it's done in the proof of the Arzela Ascoli Theorem), you should be able to show that if $n \geq M$ and $x \in [0,1]$, then $|f_n(x)-f(x)|<\epsilon$.
This proof is similar to the usual proof of the Arzela-Ascoli Theorem.  That theorem doesn't answer the question becuase it only asserts that a subsequence converges uniformly, not the whole sequence.  The condition given on $(f_n)$ in this problem could be replaced by the more general condition that the sequence $(f_n)$ is equicontinuous.
I have left some gaps for you to fill in.  The "$\epsilon/10$"s are overkill and could probably be replaced by $\epsilon/3$.
ALTERNATE PROOF if you are allowed to use the Arzela-Ascoli Theorem:
Let $f$ be the limiting function: that is, $f_n(x) \to f(x)$ as $n \to \infty$ for all $x$.  Your assumption on the $f_n$'s implies that $(f_n)$ is equicontinuous.  Since $(f_n(0))$ converges, $(f_n(0))$ is bounded.  Use this and the equicontinuity to show $(f_n)$ is uniformly bounded.  It follows that $(f_n)$ has a subsequence that converges uniformly, and since it converges pointwise to $f$, the subsequence must converge uniformly to $f$.  More strongly, any subsequence of $(f_n)$ has a subsequence converging uniformly to $f$.
Now define the sequence $(d_n) \subset [0, \infty)$ by $d_n = \max_{x\in [0,1]}|f_x(x)-f(x)|$.  All you have to do now is show $d_n \to 0
$ as $n\to \infty$.

Prove sequence converges uniformly


I found a webpage with solution to a question. Should I summarize it in an answer, or link it in comments?

Question: I found a webpage that lists many possible solutions to this question. I wonder, in such cases should I just post the link in comments, or write an answer summarizing the content with citation? I'd do the latter, but I concern if this is frowned upon on the site. Also, the webpage is easily found as it's the first result of googling "prevent apple browning".
Answer: Stack Exchange is meant to be more of an end-user publication than a list of links. The folks here will work hard to curate this collection of knowledge, so when someone finally finds this site through search, the last thing we want to do is send them elsewhere to find that information.
Add value by writing actual answers
Links sending users elsewhere to find that information aren't really considered an "answer" in the context of this this site. The goal is to try to add value to this site with your knowledge — links and citations are great as supplementary material, but relying on them heavily doesn't really add any value to the Internet.
And please do not post answers or links in comments. Comments do not have the features needed to properly vet whatever you say there, so answering in comments should almost certainly be flagged and removed. Links in comments are even worse. That only adds another barrier between the user and the actual information they are searching for — the information they expected to find here. It just sends users away to find the information themselves, and that's not what we do here.
Answer: Links rot.
Go to older SE sites and try to follow the links given in their old answers.
Way too many links have moved or are dead now. Link-only answers in that stage are now truly useless.
Links are great: great for the internet, great for giving credit, point to way more info than is expected or feasible in one answer etc. We need them. But they die.
So:

link!
cite and quote some central stuff (and give credit, do not plagiarise)
paraphrase and summarise

At least the gist of the link target should be preserved in your answer here. And it has to be your own answer after all. Write an introduction, interpret what's at the link, draw your own conclusions.


How to safely view a malicious PDF?

Question: I have a PDF with important information that may contain malware. What would be the best way to view it?
Comment: Is it of a JS kind? I think you can turn off JS.
Comment: If a PDF contains malicious software then it no longer should be viewed.  Besides non-malicious content likely doesn't even exist.  You could also open the PDF file in a Linux virtual machine, but like I said, the content is likely gone.
Comment: The thing I would do is open it in a virtual machine without network access.
Comment: There may be a question here as to whether static or dynamic analysis is most effective.
Comment: @curiousguy - ok. I don't know this. Why does someone have legal JS code in a PDF OR What does it do that a non-JS PDF cannot?
Comment: Open it up...but not in an old version of adobe reader etc that has known vulnerabilities. Safest way is in a VM but that doesn't mean when you find nothing and open it on your normal machine it is safe.
Answer: Document-based exploits are directed not at the document itself, but rather at some vulnerability in the viewer. If you view the document in a program that isn't vulnerable (or in a configuration that inhibits the vulnerability), then you won't be exploited.
The real issue is knowing whether or not your viewer is vulnerable, which usually means knowing specifically what the exploit is. But there are alternate PDF viewers such as foxit or even Google chrome's built-in viewer that do not necessarily have the same vulnerabilities as Adobe's official viewer. This is not necessarily true for all vulnerabilities, so it's important to understand what you're getting in to ahead of time.
EDIT
If you find yourself frequently dealing with potentially malicious materials, it would be very wise to set up a hardened virtual environment. I'd recommend booting into a Linux system and running your target OS (usually Windows) in Virtualbox or a similar environment. Save a snapshot of the virtual OS, and then revert to that snapshot after you're done interacting with the malicious content. Also, it's not a bad idea to run the host Linux environment from a read-only installation (i.e. Live-CD).
Comment: Reasonably simple setup would be a VM + [Sandboxie](http://www.sandboxie.com/) + [DigiSigner](http://en.wikipedia.org/wiki/DigiSigner)
Comment: @FirstNameLastName be weary of using lesser known products to avoid infection. 1: the product may use a common library and unknowingly be actively exploitable and 2: it may not be getting patched as often or as quickly as more main stream products. Hardened VM really is the only way to be sure.
Comment: Note about the edit - most modern Linux systems have several native PDF viewers available (including a ancient version of Adobe Reader, usually you don;t need to bother with that - I suggest using Okular, and most versions of evince and mupdf work great as well), you don't need to use a Windows VM....
Comment: The main vulnerability in adobe (which I don't use) is using javascript to call on an insecure undocumented API it run shellcode. I used origami to decrypt and decomporess and pdfid to check if it has javascript triggers (which it doesn't)... but I guess this doesn't even matter for anyone not using adobe viewer.
Comment: I don't use foxit or adobe. I use an obscure reader. Recently, it crashed when i opened a pdf file. Can this be a malware attack? How do I check?
Answer: Put it through a PDF viewer that isn't vulnerable to the exploit. If it's someone else's viewer, that's even safer. Try Google Docs, where they will parse it and display it as HTML, so the malicious payload won't harm you. (I'm sure that their PDF parser is extremely secure, so you shouldn't feel bad about possibly infecting them.)
Comment: I don't want to give the information in the PDF to google but thanks.
Comment: Using Google Docs is good advice, but "Put it through a PDF viewer that isn't vulnerable to the exploit" sounds strange to my ears. Usually, you don't know whether a particular viewer is vulnerable until it's too late.
Comment: @DmitryGrigoryev if the exploit depends on javascript as almost all of them do, then a viewer that does not support javascript makes that exploit impossible. An exploit that depends on file attachments is rendered impossible by a viewer that doesn't support attachments. An exploit that depends on retrieving data from a URL cannot work if the viewer does not support retrieving data from a URL. And so forth.
Comment: @barbecue If avoiding "almost all" exploits is good enough then by all means one should stick to a PDF viewer without JS support.
Comment: @DmitryGrigoryev I'm not sure what your point is. An exploit specifically targeted to work with Sumatra is possible, as I stated in my answer. Its likelihood is exceedingly small. If you're claiming there is a way to eliminate 100% of all exploits, you're simply wrong. No such method exists.
Comment: @barbecue "If you're claiming there is a way to eliminate 100% of all exploits, you're simply wrong." - I'm not claiming that, it's B-Con who suggests to "Put it through a PDF viewer that isn't vulnerable to the exploit". Also, if you're not sure what my point is, you can just let B-Con answer.
Comment: @barbecue: The phrase "isn't vulnerable to the exploit" is a casual term and the context of the question is important. Despite the fact that there are no 100% foolproof methods to thwart malware, in practice we find ways around malware. I'm recommending the OP analyze the perceived threat and put it through a PDF parser that is likely to not be vulnerable. A third-party PDF parser transfers the majority of the risk to a third party and that party's risk is likely low because they likely have designed to handle malware cases.
Comment: @B-Con I think we're in complete agreement. Almost all PDF exploits depend on executing malicious scripts. Completely eliminating the ability to execute scripts means you're immune to all such exploits, which is the majority.
Answer: Use pdf.js with a sandboxed browser (such as Chromium or Firefox) in a virtual machine without network access.
It should be quite tricky for malware to get out of this.
Answer: In this situation I've always used the Unix/Linux/OSX shell command "strings". On  *nix systems, do this:
strings ScaryFile.pdf | less

You can also get "strings" for Windows, as mentioned by Polynomial, below. You can download it here. Runs on XP or higher. Here is an example of using it on Windows:
strings ScaryFile | findstr /i TextToSearchFor

But for the rest of my answer here I'll assume you're on *nix, since that is my experience with strings. Assuming all you're looking for is text content (not bitmaps or vector graphics), you can scroll down or search and find bits of the text you need. Unfortunately, to find it you have to wade through tons of metadata, most of which is in XML, and formatting settings in some other markup, plus some binary (as ascii, not raw bytes). So you may want to use the search capabilities of the "less" command. To search down the document for the case-sensitive string "thingyouwant", use the slash key + your string + return:
/thingyouwant

Then hit the "n" key to see the next instance of "thingyouwant", over and over till you find what you want. You can use the "?" key to do the same thing in the upward direction. See the less man page (type "man less") for more magic.
You could also analyze things like which URLs the document links to:
strings ScaryFile.pdf| grep -i "http" | sort | uniq | less

But, as stated above, 99% of what you'll see from the output of "strings" is going to be metadata and formatting settings.
Comment: You shouldn't rely on strings for security: http://lcamtuf.blogspot.ca/2014/10/psa-dont-run-strings-on-untrusted-files.html?m=1
Comment: [Windows has strings too](http://technet.microsoft.com/en-us/sysinternals/bb897439.aspx).
Comment: +1 for strings(1) and pdfinfo with a followup in evince. Paging through the file looking for JS and calls to outside resources is quite effective if a bit slow.
Answer: A simple and straightforward way to open possibly malicious PDFs on a Windows computer is to use the Sumatra PDF viewer. Sumatra is a small, lightweight PDF viewer that has no support whatsoever for interactive fillable forms or javascript in PDF files.
Sumatra also has configuration options to lock it down even further, such as preventing file system or internet access.
The PDF file format has many interactive features intended to make the format more useful, but which create significant security risks, including:

The use of javascript to provide interactive content , which allows automation of the user interface
The ability to interact with the local file system
the ability to issue an HTTP request to a remote server
the ability to carry a payload of arbitrary file attachments, including malware
the ability to present a fillable form to the user, and then capture and act on the information filled in

These abilities combined together make a powerful toolkit for an attacker. Many so-called "drive-by download" attacks rely on the use of PDF files.
Common PDF viewers attempt to provide safety for these features by creating sandbox environments or giving the user prompts, but these solutions are both more complex (and therefore subject to their own vulnerabilities) and less compatible with other parties' products than the simpler solution of leaving out that functionality entirely.
Sumatra is one example of a PDF viewer that does not provide many of the functions which are most commonly used in PDF exploits. By completely eliminating entire categories of potential attacks, such programs greatly reduce the risk of viewing unknown PDF files.
A further advantage of using a less popular viewer is that because it's both less common and less powerful, it's a less interesting target.
The Sumatra viewer could be possibly be exploited by a specially crafted PDF which takes advantage of some unknown bug to cause a buffer overflow, for example. Such cases are rare however, and there have not been any significant security exploits for Sumatra in recent years.
Comment: There's no need to be rude. I did read your answer in full, yet I fail to see what makes Sumatra so special. There are plenty of PDF viewers which either don't support JS or let the user disable it.
Comment: What makes you think Sumatra is safer than any of the 1001 other PDF viewers out there?
Comment: @DmitryGrigoryev My reasons for thinking this are clearly stated in my answer. I recommend re-reading the first paragraph and looking at the link in the second paragraph. You will find your answers there.
Answer: Use a virtual machine that can be reverted to clean slate after tests. If the PDF reader is vulnerable, your real workstation will be much  less likely to be affected.
Answer: Latest versions of Adobe Reader (version 10.1 and up) support "Protected Mode" or sandboxing which can be used to view untrusted PDF files. This effectively restricts the access of the process displaying the PDF file to %appdata%\Adobe\Acrobat and other PDFs which are explicitly opened by the user.
Protected mode has to be activated by going to Edit->Preferences menu and selecting either General or Security tab, depending on the version:

Obviously, you'll want to close any sensitive PDFs like your bank statements before opening the untrusted one.
Comment: What is consiered as "unsafe location"? For example, would that be triggered if you open a document from a USB thumbdrive?
Comment: @Jean-FrancoisT. I don't use Acrobat anymore, but as far as I remember, yes, thumbdrives are considered unsafe locations. Trusted locations are your local drives, excluding problematic folders such as "Downloads" and "Temp", anything else is untrusted.
Answer: We can say ALL of the in-the-wild or targetted attack using malicious PDF file are covered with obfuscation techniques to hardened the analysis or detection process.
Most of the obfuscation technique are mainly using JavaScript obfuscation like eval(), String.fromCharCode(), arguments.callee(), base64, and even with PDF key values such as /Author, /Keywords, /CreationDate and etc.
We might unable to view the content of the malicious PDF file (those within the PDF object stream) as it might be deflated commonly with FlateDecode. But there are tools available to allow us to inflate the content within the PDF object stream, such as pdf-parser (http://blog.didierstevens.com/programs/pdf-tools/) and FileInsight (http://www.mcafee.com/us/downloads/free-tools/fileinsight.aspx). Most of the obfuscated JavaScript code will lies within the inflated PDF stream.
We can advise you to get the latest patched version of PDF reader with turned-off JavaScript functionality to open the file, but the good solution is to get a virtual machine where you can delete it or revert the snapshot after opening the file.
Answer: Another easy and less time consuming option is to open it in the Sandboxie app, which would isolate it.
Comment: Considering this answer is written in 2017, I wonder why you advocate using Sandboxie instead of the [sandbox](https://security.stackexchange.com/a/162444/71607) built-in into Adobe Reader.
Answer: You can open the PDF in a container. Here's a docker image you can use: https://hub.docker.com/r/chrisdaish/acroread/
MY_PDF_DIR='/tmp/foobar'
docker pull chrisdaish/acroread
docker run  -v $MY_PDF_DIR:/home/acroread/Documents:rw \
        -v /tmp/.X11-unix:/tmp/.X11-unix \
        -e uid=$(id -u) \
        -e gid=$(id -g) \
        -e DISPLAY=unix$DISPLAY \
        --name acroread \
        chrisdaish/acroread

This will open an Acrobat Reader that will display via the local X server.
The approach reduces the attack surface, but not 100% safe as it's got access to your X server.
Answer: You can use a less popular viewer/OS combination. I guess no one targets Okular running on FreeBSD (though it can still be vulnerable), so if you open the file in a VM you should be very safe.
In order to do harm the rogue payload must match the viewer version and the OS and the CPU architecture of course. It is really low-level assembly and memory stuff (the payload expects to be placed at a particular memory address and expects some standard system functions to be available). If you change any of those, then the payload may not execute properly (or the viewer may simply crash without doing harm).

How to safely view a malicious PDF?


Pipe is fine, solenoid is fine, but can't get hot water into my washing machine?

Question: So let my start off by saying, the installation techs installed the valves backwards at first, so I was getting hot water out of my cold, never noticed that until my room mate was pissed at me for washing on hot because it was going to make our electricity go up... So I switched the hoses blue to blue, red to red, now only cold water comes out!! Figured it was the hot water valve/solenoid, so I got a new one. Nope. Same problem. If I set to hot water and turn off the cold water I get a humming noise and no water comes out, or if I keep the cold water valve on, only cold water is coming out. What is the issue?! Is it the technicians fault? Did they screw sensors up by installing backwards? I have a Samsung model WA40J3000AW/A2. Brand new, no clogs or anything that I can gather. valves are clean. water comes out of both pipes when disconnected from the washer at the correct temperature.
Comment: Have you checked the hose/valve filter for blockage? occasionally I've found rust, etc., blocking the water. Have you checked that there is hot water to the hose, and there is no shut-off upstream & back to the water heater?
Comment: Sounds like a warranty issue to me if the valve is buzzing the line after it may be blocked, since you had hot water running through the cold valve the supply line is good.
Answer: If it is delivering cold when you call for hot only then it is opening the wrong valve (assuming your statement that the hoses are correct now is true).
Return the unit, it is malfunctioning and it seems like a controller issue not a valve or solenoid issue.
However; you state that you replaced a "valve/solenoid". Are you certain you did it right? Are you certain you wired it right? If the unit was "brand new" why did you do that yourself instead of having a factory approved technician troubleshoot and repair the unit under warranty?


What is the best way to analyze non-quantitative mass spec hits from an immunoprecipitation pull down?

Question: I am studying a nuclear protein and want to come up with a list of potential proteins that it interacts with. From the nuclear fraction of 293T cells, I did an IP (immunoprecipitation) to pull down my protein and submitted whatever I pulled down for a mass spec analysis. I also did an IP with a non-specific antibody as a control. I got a huge list of hits, and I'm not sure how to prioritize them. I can manually remove the hits that also came down with the non-specific antibody, those are obviously just sticky proteins. I looked around Pubmed for ways to prioritize non-quantitative mass spec hits, but I'm not sure if any of them would work in my case. All of them require multiple mass spec repeats - I can do that if I need to, but would like a way to look at my initial data more intelligently.
Comment: The title refers to quantitative data but your question seems likely to be describing shotgun proteomics (where peptides are selected for MS/MS based on their intensity) which is not necessarily quantitative. Could you clarify this so that the question can be answered correctly? Also, the facility that has performed the analysis is likely to offer a basic consult on data interpretation.
Comment: @Michael_A its suppose to be quantitate. I apologies for the typo.
Answer: If they are available, talk to the people who analysed your data. Using their knowledge is intelligent.
I will assume two critical steps are completed. First that your results have been searched correctly. I will also assume that the peptide and protein identifications have been filtered to provide a false discovery rate of 1:100 at each level.
You can remove all the proteins that were identified in your affinity purification control. Another option is to use the Contaminant Repository for Affinity Purification (the CRAPome) which provides a formal framework for removing contaminant proteins. It is a nice resource if your data are compatible.
The remaining proteins are what you have to work with, this is the

list of potential proteins that [your protein] interacts with.

Prioritise these proteins based on the biology of your experimental system. If the list is small work through the function of each protein and assess how it fits with the biology you are researching.
To assess the potential functional links between the proteins you can create an in silico network. Markov clustering can highlight the presence of functionally distinct groups of proteins within a network. String, linked above, can do this. Centrality measures can indicate the presence of proteins with the potential to influence the behaviour of the network.
For larger lists you can also assess the function of the proteins in the list by performing a functional annotation enrichment analysis. There are many other things you could do but the primary goal is to keep biology at the forefront of your efforts.
Finally you mention that repeats are necessary. Analysing the data is time consuming. If this was a test run verify that the test was successful and then run the replicates. Time spent analysing incomplete data can be spent completing the data set or ensuring the right data is collected. Quantitative data can be very useful and with care shotgun proteomics approaches can provide quantitative data but the people who run the machine need to be consulted when quantitative data is required.
Answer: You can look for the most abundant proteins in your sample. Although, as you say, the LC-MS analysis of your IP was non-quantitative, you can still try to get some quantitative estimation. To elaborate, you can use for example sequence coverage, no. of PSMs for each protein, no. of peptides ID'ed for a protein, share of spectrum ID, etc, as proxies for abundance.
There exists rough correlation between abundance of a protein and all these quantities. If a protein is more abundant you are more likely to have more number of peptides ID'ed from it, more no. of PSMs assigned to it, it would have higher sequence coverage, etc. Different people use different things. I have often used no. of PSMs normalised by length of the protein as an estimation for the abundance of that protein.
As others mentioned, discuss with the people who analysed your data. As a rule of thumb, I would filter my data first on 1% FDR at the PSM level, then at the Peptide level and then at the protein level. Then I would throw out all the proteins that were not identified by at least two unique peptides. Then I would compare the proteins ID'ed in the negative control list and remove the common IDs. Then sort the remaining list on no. of PSM for each protein. This would give an estimate of the more abundant proteins in the IP sample. To give an example, your bait protein (protein against which you did the IP) should be the most abundant protein in your sample. Proteins after this could then be assumed to be interactors of your bait.
Do remember that this is not a proper quantitative way of measuring protein-protein interactions by affinity purification coupled to LC-MS. But, it is a useful start. I always used preliminary information from such an analysis to design better ones. Also, read about reciprocal IPs to confirm interactions.


Side Effect of Lyrica medication

Question: Due to nerve swelling I was taking Lyrica medication for a few weeks,  but after I started to take the medication I started to feel some side effects, such as swelling eye in the morning, appetite problems and a few more. Has anyone had same situation after taking Lyrica medication?
Answer: Side effects of drugs such as Lyrica (pregabalin) are collected by the manufacturer in clinical trials as well as post marketing surveillance, case reports and by regulatory agencies.
Drugs.com has a page describing side effects for this drug, and oedema, weight change are included, and maybe even the others you haven't mentioned.  However, because you've noticed a particular symptom, it may not be related to the drug and sometimes you have to stop and restart to see if the effect is reproducible and therefore more likely to be caused by the drug.
Comment: After I'm stop the medication the symptom is no more or less compare to when i taking the medication. Anyhow the website you gave have a lot of information im actually I'm need ... thank you for that :D

Side Effect of Lyrica medication


How do chameleons signal cells to change color?

Question: I have read about how they can change color, but is there literature about the chemical signaling process they use to do so?  I read that it could be some combination of hormones and neurotransmitters, but I couldn't find specific information on the receptors or chemical mechanisms.
Answer: As said by @dblyons, there has not been a lot of research (biochemical) on chameleons. So, the exact part of mechanism that you're looking for is still not understood. However, we have recently caught the broad end of the stick. Chameleons don't have special cells for color, their complete skin has a layer of pigments (dermal iridophores) which helps them in changing color. See this (or this) article:

Chameleon skin has a superficial layer which contains pigments, and under the layer are cells with guanine crystals. Chameleons change color by changing the space between the guanine crystals, which changes the wavelength of light reflected off the crystals which changes the color of the skin.

These guanine crystals are actually like colorless mirrors, but by changing the distance between these crystals, wavelength of light absorbed (and reflected) can be changed. It is quite similar to how the color of ozone changes from pale blue in gas to violet-black in solid form. However, how chameleons trigger this change in distance of crystals, is not yet known.
This is how these crystal lattice works:
sourcesource
This is what a guanine crystal looks like ((a) is guanine):

You can also see a nice real-time video of guanine crystals changing color of chameleon here.
The color changing portion of skin has 3 main layers:

superficial s-iridophores which help in changing color in visible region rapdily.
deep d-iridophores which reflect light in infrared refion and are thought to provide thermal protection to chameleon.
layer of melanin which is actually yellow in color, making chameleons naturally yellow(!) in color. When the guanine crystals come closer, they reflect the blue portion of visible spectrum. This blue light, along with the natural yellow color of melanin, becomes green which gives green color to chameleon. So, the actual color visible to us is a combination of color reflected by guanine crystal and yellow color of melanin.

As I said already, the exact biochemical signalling process behind this process is not known yet. It could be complex hormonal or neurotransmitter signals. However, hormones are considered as the main triggers because chameleons have been shown to change color due to changes in mood instead of environmental protection.

Cephalopods such as the octopus have complex chromatophore organs controlled by muscles to achieve this, whereas vertebrates such as chameleons generate a similar effect by cell signalling. Such signals can be hormones or neurotransmitters and may be initiated by changes in mood, temperature, stress or visible changes in the local environment.
Comment: the thing i didn't like about the chameleon wiki was that they cited a national geographic article... no primary source
Comment: @dblyons I have added another citation in the first paragraph which has (quite) plenty of references. Please let me know if it helps.
Comment: it doesn't.  the original citation is this paper: http://www.nature.com/articles/ncomms7368
Comment: @dblyons This nature article has also been cited in the reference I added. Along with it are many other citations including some books too.
Answer: This is a good question and... kind of remarkable because I don't think there is a specific body of literature regarding chameleons.
Generally though, vertebrate skin cells responsible for color (these cells are called chromatophores and arise from the neural crest during development) are responsive to the hormones melatonin, MSH, and others.  These hormones, which are released from the pineal (melatonin) or pituitary (MSH), bind GPCRs on the surface of the chromatophores which elicit intracellular activation of PKA, for instance.  This activity can cause mobilization of pigment within the cells.  This article about fish coloration may help guide you somewhat in your studies, but chameleons in particular seem like an understudied clade of color-changing animals!


Does it really matter to distinct between short, int, long?

Question: In my C# app, I would like to know whether it is really important to use short for smaller numbers, int for bigger etc. Does the memory consumption really matter?
Comment: Stupid people don't understand...

[StructLayout(LayoutKind.Sequential, Pack = 1)]

You can make base class and define field as you need in derived.
Answer: Unless you are packing large numbers of these together in some kind of structure, it will probably not affect the memory consumption at all.  The best reason to use a particular integer type is compatibility with an API.  Other than that, just make sure the type you pick has enough range to cover the values you need.  Beyond that for simple local variables, it doesn't matter much.
Answer: The simple answer is that it's not really important.
The more complex answer is that it depends.
Obviously you need to choose a type that will hold your datastructure without overflowing, and even if you're only storing smaller numbers then choosing int is probably the most sensible thing to do.
However, if your application loads a lot of data or runs on a device with limited memory then you might need to choose short for some values.
Answer: For C# apps that aren't trying to mirror some sort of structure from a file, you're better off using ints or whatever your native format is.  The only other time it might matter is if using arrays on the order of millions of entries.  Even then, I'd still consider ints.
Answer: Only you can be the judge of whether the memory consumption really matters to you. In most situations it won't make any discernible difference.
In general, I would recommend using int/Int32 where you can get away with it. If you really need to use short, long, byte, uint etc in a particular situation then do so.
Answer: This is entirely relative to the amount of memory you can afford to waste.  If you aren't sure, it probably doesn't matter.
Answer: The answer is: it depends.  The question of whether memory matters is entirely up to you.  If you are writing a small application that has minimal storage and memory requirements, then no.  If you are google, storing billions and billions of records on thousands of servers, then every byte can cost some real money.
Answer: There are a few cases where I really bother choosing.

When I have memory limitations
When I do bitshift operations
When I care about x86/x64 portability

Every other case is int all the way
Edit : About x86/x64
In x86 architecture, an int is 32 bits but in x64, an int is 64 bits
If you write "int" everywhere and move from one architecture to another, it might leads to problems. For example you have an 32 bits api that export a long. You cast it to an integer and everything is fine. But when you move to x64, the hell breaks loose.
The int is defined by your architecture so when you change architecture you need to be aware that it might lead to potential problems
Comment: The x86 vs x64 argument is wrong in C# - `int` is an alias for `System.Int32` (see [MSDN](http://msdn.microsoft.com/en-us/library/ya5y69ds.aspx) ) If you want the platform native size then I think you need to use IntPtr.
Comment: I don't understand "When I care about x86/x64 portability". Can you explain this?
Comment: I don't know about C#, but in C an `int` is 32 bits on amd64 and x86. It's the `long` that changes size.
Answer: That all depends on how you are using them and how many you have.  Even if you only have a few in memory at a time - this might drive the data type in your backing store.
Answer: Memory consumption based on the type of integers you are storing is probably not an issue in a desktop or web app.  In a game or a mobile device app, it may be more of an issue.
However, the real reason to differentiate between the types is the kind of numbers you need to store.  If you have really big numbers, or high precision, you may need to use long to store it.
Answer: The context of the situation is very important here.  You don't need to take a guess at whether it is important or not though, we are dealing with quantifiable things here.  We know that we are saving 2 bytes by using a short instead of an int.
What do you estimate the largest number of instances are going to be in memory at a given point in time?  If there are a million then you are saving ~2Mb of Ram.  Is that a large amount of ram?  Again, it depends on the context, if the app is running on a desktop with 4Gb of ram you probably don't care too much about the 2Mb.
If there will be hundreds of millions of instances in memory the savings are going to get pretty big, but if that is the case you may just not have enough ram to deal with it and you may have to store this structure on disk and work with parts of it at a time.
Answer: Int32 will be fine for almost anything. Exceptions include:

if you have specific needs where a different type is clearly better. Example: if you're writing a 16 bit emulator, Int16 (aka: short) would probably be better to represent some of the internals
when an API requires a certain type
one time, I had an invalid int cast and Visual Studio's first suggestion was to verify my value was less than infinity. I couldn't find a good type for that without using the pre-defined constants, so i used ulong since that was the closest I could come in .NET 2.0  :)


Why do newswriters separate women when they report on disasters?

Question: It's commonly known that the news reports female casualties separately. As in "four people were shot, including one woman". What is the reasoning behind this? Is anyone who knows about the news reporting process able to answer?
Comment: It has similarly bothered me whenever the reporter counts the Americans separately.  "130 people died in the plane crash, including 12 Americans."  I assume other countries do it as well.  I'm wondering whether I should care more about those 12, or ask, "But wait!  How many were French?"
Answer: Makes an emotional and social impact
Making a point of how many women and/or children perished or were harmed in a given event makes a larger emotional and social impact. It turns the causative entity into a cruelty or an horror, be it an impersonal force such as nature or certain views on god(s), or be it a personal force such as a person, group of persons, or representational organization.
Most cultures, regardless of how advanced they see themselves, will in reality react more strongly to harm towards the female or the young of the species.
The news is in the business of selling stories. And stories with a twist or a bang sell more.
Answer: Do they really still do that? The origins are not hard to guess at. It has been a fundamental social presumption for centuries that the essential role of men is to protect women and children. On sinking ships, the rule was women and children first, and woe betide a man who survived a shipwreck in which a woman or child perished.
And of course this rule was pretty much a practical necessity at anytime up to the creation of civilian police forces. Routine protection of persons in everyday life was simply not a function of government up until quite recently, or at least no one it had the means to effectively carry out.
But do they really still do it? And if they do, is it perhaps just a cultural survival, or do we really still think that women's lives matter more?
Comment: I just googled the word "civilians" and the third top story had the headline "Dozens of civilians, incl women & children, killed ..." So I guess they do still do that.
Comment: @MarkBaker Love you man, but answering with a question is bad form.
Comment: In Israel, I've never seen it done, unless the woman was pregnant. You do see "mother killed protecting her children", but that's about making the victim human, not faceless. It could have just as easily been "father killed protecting his children". However, Hebrew is a gendered language, so "soldier killed", for instance, is automatically either "male soldier killed" or "female soldier killed" - there's no neutral.


Saddlebag Laptop advice

Question: I live close enough to work that I'm able to bike there and back every day. I also pack a laptop in a backpack. I am seeking ways to reduce the weight on my back. I've only seen people use saddlebags on a bicycle 1-2 times my entire life so I'm looking for advice. Has anyone tried to pack a laptop in a saddlebag before and how did that turn out? What are common issues/features I should look for in a saddlebag? I can only think of two things to look for at the moment: 1) impact resistance (not crushing my laptop) and 2) water proof if possible.
Comment: @Rider_X Lol! There were sooo many dead grandparents! Eventually I sprung one undergrad who claimed the same one had died twice :-) Yes, you're right about SSD's, and I'm impressed that you carried your laptop on your bike. It's good to give the OP multiple viewpoints.
Comment: @andy256 - Anyone who has critical data on a laptop that they transport around and who does not have a scheme for doing daily backups is a fool.
Comment: If you're still doing your PhD then I would advise against. No matter how well backed up you are, you'll always have stuff on the laptop that would be a problem to lose. IMHO a laptop is safer on your back. Spoken as a supervisor who has seen too many students lose their work :-)
Comment: @andy256 Really your students lost work because it was in a bike bag. That is not a bicycle problem.
Comment: @andy256 - As reformed PhD student (aka graduated) who carried their laptop on their bike everyday I humbly disagree. I backed up daily and never once lost data to a bike trip. I even toured between conferences (across Norway by dirt roads) with no problems. I think this is even less of an issue now with most laptops being solid state storage. Perhaps the grad student "lost data" is like the undergrad "dead grandparent" syndrome at exam time?
Comment: @andy256 - for giggles you should include a [randomized response survey](http://en.wikipedia.org/wiki/Randomized_response) on an exam. My former supervisor estimated undergrad cheating at over 50%.
Comment: I do most of my work on an off-site server and all local documents are backed up through dropbox so I'm not too worried about data loss.
Answer: I have carried a laptop on my commute bike for closing in on 15 years now. Mainly in panniers (saddle bags). For a little while in a courier bag when when I was young and dumb. For what it is worth (aka the dangers of anecdotal evidence) I didn't have any laptop failures directly related to a bike trip.  I even toured with a 17inch laptop across 800 km of mixed terrain (road and dirt) in Norway with out incident (riding to a workshop and conference).  That laptop is still going strong 5 years later.

Waterproof pannier.  Water is the enemy of most electronics. So is dust.  It pays to be able to keep things very well sealed.
Well padded case. I used to use a well padded sleeve to house the computer and moved to a pannier with a built in padding.
Strong mounting. Not all bags are created equal.  Get ones that have rigid re-inforced back plate and strong mounting system. You don't want the bag flopping around.  Cheap panniers can sometimes twist into the spokes which will likely result in damage to your laptop during the ensuing carnage.
Strong pannier rack.  As a corollary to (3) if you have a cheap flexible rack this could also cause problems, but I haven't personally had any problems across a variety of rack types. Some racks also support panniers against twisting better than other racks.
Back it up just in case...  This is really good advice regardless of transportation method.  I always keep at least two backups going, one in the office and one at home (offsite).  I once came into my office to observe my desk under water.  If I had left my laptop there I would have lost it and the backup sitting on the desk.

Other Deep thoughts...
I have always wondered about the impact of vibration, but so far I haven't seen any clear indication (warning anecdotal evidence).   I had one hard drive die spontaneously while working on a report. Perhaps vibration shortened its life?  It it was also very hot that day and I was without air conditioning and I was running some simulations so the temperature could have fried it too.
I have also had a lust for well built laptops, which may have stood up better.  I am a hipster poser so you can guess which brand of computer I have continually purchased.
Comment: @andy256 - To cover IP I use full volume encryption on all backup drives (and the laptop).  Backup via Dropbox is even worse than it first appears as it is a sync service, not a backup service.  All the potential short comings are best left to another SE forum.
Comment: It is worth worrying about vibration, as that is probably a bigger killer of electronics than "shock".  But you covered most of the bases -- make sure the rack is rigidly mounted to the frame and that the bag is securely mounted to the rack and will not flop around.  And I figure that it's good to have the laptop in a padded case, and maybe a little extra foam on the bottom of the bag.
Comment: Good point about two backups, one at home and one at work; that's the way I always work (IP rules permitting). The OP mentions in comments backing up using DropBox. I would not be comfortable if all of my PhD work was reliant on the vagaries of *one* backup system. You only know your backup system has failed when you *needed* it. Past tense.
Comment: When it comes to vibration (and some shocks) , solid state drives are great but with spinning disc hard drives be sure to shut down or hibernate so that the heads away from the platters.
Comment: Thanks! You brought up a lot of good points. I would not have thought of #3 and #4. I'll have to do a little more research into the question about vibration damage. My riding is on paved roads/sidewalks so a well padded bag may solve that issue.
Comment: @JoshBradley - I think vibration was more of a worry with older electronics.  Modern electronics are highly integrated with fewer parts.
Comment: @Rider_X Dropbox has its place as a means of distributing backups but I agree it's not a backup solution especially as a major cause of lost data is things like deleting the wrong file - which Dropbox promptly deletes at the other end as it syncs.
Answer: I haven't carried a laptop in a saddle bag but I have used them a fair amount.
You can definitely find a waterproof saddle bag that will carry a laptop.  If your commute is smooth (i.e. pavement) your laptop should be fine.
Two things to consider when choosing a saddle bag:
1) Ease of removal/attachment.  Unless you are going to leave it on all the time, this could become a factor in quality of commuting life.
2) Heel clearance.  Depending on your position, shoe size and rear rack you want to make sure your heel isn't going to hit the saddle bag.
Comment: +1 for the point about heel clearance. Many road bikes won't have enough clearance with many panniers.
Comment: Thanks Carey.  I have the issue sometimes with my bags which is why I mentioned it. I have a little bit of wiggle room with where I mount my bag, but not a ton.
Answer: There are good bike bags for lap tops.
Need water proof, padding, and solid mounting.
Mount and unmount rapidly.
Also consider how it carries off the bike.
Does it look like a brief case so you can use it like a brief case during the day.
To deal with length on the front wheel can help - that is how I carry.
I don't like putting out a names but like the Otlierb Office.
As far as damaging it takes a bit of shock to break a lap top.
The vibration on a bike is not likely to harm a lap top hard drive.
I have dropped lap top hard drives on the floor and not broken them.
One thing is power it all the way down (not snooze) so the drive is parked.
A pack tends to be soft so it will conform to your back.
I have lost a couple screens due to the flex.
I think a semi rigid bike bag is better than a pack.
The quality of the laptop is a big factor
Look for a laptop with a metal case
Soft plastic will bend and hard plastic will crack
Cheap hinges will wear out
I used to do lap top repair

Saddlebag Laptop advice


Is allowing Full HTML (HTML filter on) input for all user roles safe?

Question: Is allowing Full HTML input for all user roles safe as long as I enable the HTML filter?
Comment: If you add the HTML filter to Full HTML, how is it different from the existing Filtered HTML input?
Comment: Then why wouldn't you just give them the Filtered HTML input?
Comment: I have some content written by an admin that seems to use the default input filter. I want it to use full html.
Comment: There's no difference? It just says it removes javascript and harmful stuff. Not sure
Comment: HtmlPurifier solved my problem
Answer: Only trusted roles and users should have access to Full HTML. You can add some additional allowed tags to the Filtered HTML input format but don't add too many or you risk creating a vulnerability. (admin/settings/filters)
Comment: Is it possible to allow inline css for allowed tags?
Comment: You can only add _some_ additional allowed tags to filtered html and still keep it safe. Enabling "full html" for anonymous or putting too many (unsafe) tags into filtered html are two of the most common ways I've seen to make a site insecure.
Comment: To the question "is it possible to allow inline css" - no, Drupal does not have a good tool for filtering CSS to remove cross site scripting.
Comment: @glumbo There's a module for allowing/disallowing certain HTML tag attributes such as `style` (which is inline CSS): [htmLawed](http://drupal.org/project/htmLawed). Just throwing it in here maybe it will be useful.
Answer: It doesn't really matter what the name of the input format is, if "untrusted" users (see a defintion of trusted roles) are allowed to enter unsafe HTML tags then your site is unsafe.
You can make the Filtered HTML input format unsafe by adding the wrong tags to it or make the "Full HTML" input format more safe by changing its configuration.
I suggest installing the Security Review module and configuring it to know which roles of your site you trust. It will then analyze your input formats to see which are safe and which are not. It also has documentation and links to further resources if it determines that some of your input formats are unsafe. One great resource is the handbook page on configuring input formats for safety.
If you want to make a different input format the default for your admins vs. your regular users, try the Better Formats module.


Using American Airline Miles

Question: I'm trying to book a flight for my mom to Shanghai by using my AA miles but I'm not sure if I should use Anytime Miles or MileSAver Miles. If I booked her Anytime miles would the possibility of getting her upgraded to business class be higher? She will be traveling with my son who is not yet two so he will be sitting with her. I just want to make sure she's as comfortable as possible on this flight. Please advise. I've only used my miles once to book a flight for my mother in law to fly from Florida to Ohio and she didn't have any issues. In fact, she said they put her up front in the business class and gave her a glass of wine. Thanks for any suggestions.
Comment: Does the child have his own seat, or in her lap? Two upgrades are less likely than one. Also, I don't know what their policies say, but I suspect the airline may not be real keen on putting a small child in business class, who might be noisy and disturb their other premium passengers.
Comment: If you want to sit in the business cabin, the only sure-fire way to arrange it is to book a business seat! Why not book a business ticket at the saver rate and ensure it?
Comment: It is extremely doubtful that using AAnytime miles will increase your chances for an upgrade in a meaningful way— whether handled by the computer or by an agent, the process will favor fare-paying passengers over reward passengers. Operational upgrades are also extremely rare on intercontinental flights as compared to domestic ones. Related: *[What's the difference between MileSAAver and AAnytime reward tickets on American Airlines?](http://travel.stackexchange.com/questions/14531)*
Answer: Upgrades on long hauls are usually only offered when economy is oversold and there are no re-routing options for passengers they have to bump. They are not common and the chances of your mother reaching the top of an upgrade que is next to zero.
When choosing who gets upgraded, elite frequent flyers get the highest priority, ordered by their elite level and the ticket they are flying on, followed by full fare paying non-elite passengers and then down through the fares from there.
While having a FF ticket paid for at AAnytime levels puts her ahead of a person holding a ticket paid for at MileSAAver levels, that distinction likely would not come into play.
You don't really specify it, but it sounds like you plan for your son to travel as a lap child. Going from the states to Shanghai is a long time for a child almost two to sit in a lap in an economy seat.  Your mom is a saint to volunteer.  Have you looked at using MileSAAvers to get her a business class seat from the get go?

Using American Airline Miles