C3 calculation in interplanetary missions

Question: I'm starting to study Astrodynamics and I'm trying to make a Porkchop plot for a Mars mission to compare the results with actual porkchop plots which I found on the internet, so I know if my calculations are correctly done or not.
$$
$$
The thing is, that I don't understand how the C3 changes with the arrival date, as I understand, C3 has something to do with the escape velocity, being
$$
C_3=v^2-v_{esc}^2
$$
But the thing is, how do I calculate this at the arrival? as I do not want to escape but intercept a planet. And, how do I represent this in the porkchop plot? The sum of both values? I don't really understand this, so if you can help me it would be greatly appreciated.
Answer: For reasons of convenience, departure excess energy is plotted as $C_3$, and arrival excess energy is plotted as $v_\infty$, where $C_3=v_\infty^2$. The reason is that launch vehicle performance is always quoted in terms of $C_3$, whereas computing things like orbit insertion $\Delta V$ or entry velocity is more straightforward with the arrival $v_\infty$. In any case, they represent the same thing.
$C_3$ and $v_\infty$ are constants of motion for any given elliptical orbit (where $C_3$ is negative) or hyperbolic trajectory (where $C_3$ is positive), which is why they are so useful. The relation is:
$$C_3=v_\infty^2=v^2-{2\mu\over r}$$
which says that given any location in the orbit, if you compute that expression in $v$, the magnitude of the velocity relative to the central body at that moment, and $r$, the distance from the center of that body at that moment, you will always get the same result. ($\mu$ is the $GM$ of the central body.)
The departure $C_3$ and the arrival $v_\infty$ are both determined by the solution to the Lambert problem for the chosen departure and arrival dates, for which there is one orbit about the Sun that connects those bodies at those times, under some constraints. The $v_\infty$ is the magnitude of the velocity difference between the trajectory at the body intercept and the velocity of the body.
Comment: No. Velocities are always relative to something. Your transit trajectories are Solar elliptical orbits, whereas your departure and arrival velocities are on hyperbolic orbits relative to the departure and arrival bodies. You need to be careful about your "v"'s and what they mean. You will need to convert from solar-relative to body-relative by subtracting the body velocity vector. And of course you need to use the appropriate $\mu$ for the current body of interest.
Comment: `+1` I really appreciate answers that take the time to explain the meaning behind some fundamental concept that is intuitive and second nature to "orbit mechanics" but are tough for the rest of us.
Comment: Thank you very much for your answer! then, in theory if I solve Lambert's problem and get the velocity v2 and v1 (arrival and launch, respectively), if I calculate C3=v2^2-2*mu/r2 must be equal to v1^2-2*mu/r1, right? Because when I calculate it, I don't know why the result is different, and the graphic is not like a porkchop plot. I wonder where I made the mistake.


Do I need to apply for a Korean Tourist visa?

Question: I am a Philippine passport Holder with valid Japanese working visa residing in Japan.
Do I need to apply for a Korean Tourist visa?
Comment: Did you check Timatic?
Answer: According to Timatic, you do need a visa to enter the Republic of Korea, as well as evidence that you have to right to re-enter Japan (either stamped in your passport or the separate travel document issued to foreign residents).
Timatic is used by airlines to verify cross-border passenger documentation requirements. While perhaps not your carrier, Emirates has an easy and accessible search tool which you can use to check on your own.
Comment: Someone who doesn't know what Timatic is would probably appreciate a link to support this...


Work contract and own IP

Question: I'm in contract negotiations with a company which have a trial period before offering full-time employment.
Reading the contract, I felt the wording around own IP was a little vague. I am working on my own side project with some co-founders and was worried that they would be able to claim IP ownership of our work.
I asked for clarification by email. They went one better and added an appendix on the end of the contract stating that the specific project would be owned by us.
I showed this to a solicitor I know. They were surprised that the main body of the contract didn't reference the newly appended appendix (the body remains as it was). I asked for an adjustment to include a reference to the appendix in the body. They said they could not do this (stating too much behind the scenes work).
I'm wondering: Is the appendix and the reference to the appendix in the email enough? Or is the absence of a reference to the appendix in the body of the contract damning for our project?
Answer: Yes and no to each question respectively.
Comment: Thanks for your answer.  Do you mind if I ask your qualifications and how you would know this?

Work contract and own IP


Is it safe to put a Mac directly on the internet?

Question: In the past I have always run a NAT router between my Windows PC's and the internet. I'm wondering if I still need this or whether the OSX firewall is good enough to let me put a Mac directly on the internet.
Answer: Though I don't mind hooking up my Mac to any network, I don't have the definitive answer. Still, some notes too long for a comment:
The OS X built-in firewall is an application firewall: accepting incoming connections is granted per application, not per port. Once granted permission, an application could open any port it likes, but I guess that's not an issue for software you trust. Also, it only applies to incoming connections: all outgoing connections are always allowed (but that is true for a NAT-firewall as well). And according to Apple's "Mac OS X 10.5 Leopard: About the Application Firewall":

All applications [..] that have been digitally signed by a Certificate Authority trusted by the system [..] are allowed to receive incoming connections. Every Apple application in Leopard has been signed by Apple and is allowed to receive incoming connections.

In 10.6 the latter is made more explicit (and can be disabled) as "Automatically allow signed software to receive incoming connections. Allows software signed by a valid certificate authority to provide services accessed from the network.":

Hence, even when the firewall is active, every server-like Apple application that you have running is, by default, allowed to accept incoming connections. (Or, maybe in 10.6 it even applies to any signed application?) A bug in such software could compromise your computer. I don't know how that affects things like Bonjour and file sharing.
If the firewall is active then any non-Apple software (or at least unsigned software) first needs your permission to accept incoming connections. When such software is updated, it might or might not need your permission again:

A signed application [..] can mathematically prove that it is indeed a new version of the same application from the same vendor that you expressed trust for in the past. The result is an end to dialog boxes asking you to confirm a choice whose safety you have no reasonable way to verify.
Comment: +1 Informative, in-depth answer (compared to my answer, anyway :)
Answer: Of course one could go on about how in theory nothing is safe, ever, and all that.
But for practical purposes, yes, it's generally safe enough to put your Mac directly on the internet. (Everyone does it –  well, most people in any case – and it's very unlikely anything bad will happen to you.) Especially if you do not open any extra services (like httpd, etc) on your machine.
That said, do (let the automatic updater) keep your Mac OS X always up-to-date with latest security fixes, and check that its built-in firewall is enabled.
Comment: Probably a good idea to make sure the firewall is turned on (it's disabled by default in some versions of OS X).
Comment: *Everyone does it* -- that's definitely not true.
Comment: Well, *most people*, whatever. For practical purposes "everyone".  ;)
Comment: You also probably want to make sure your firewall, the one built into OSX, is set to stealth mode.
Comment: Well, I certainly wouldn't. But then, I'm not a Mac user either.
Answer: It's never secure to connect a computer to the internet, and it's always better to have a router in between.
Since most routers run embedded-Linux, it's most-likely more secure to have them in-between.
Speaking as a Linux-user: Mac OSX has most of the applications from FreeBSD, so make absolutely sure you have ssh and sshfs not installed or running, if you don't need them.
And just having a firewall is not enough. Make sure it's properly configured.
Comment: Who would ever make a router from WinCE?  That is crazy talk. OMG. http://www.marvell.com/company/news/pressDetail.do?releaseID=283 people did it.
Comment: May I ask: Why the downvote ?
Comment: Wondered the same thing ..... ?
Comment: I didn't downvote, but I would say that it isn't safer because it runs Linux (which is only as secure as how well configured it is anyway) but because it's a *router* and that is its function.
Comment: @sidran32: I disagree. A router needs an operating system, and it's only going to be as secure as the operating system, the weakest link. And if that OS was WindowsCE, then I'd rather not put a router in between. In that sense, the "always better" was probably the reason.
Answer: Considering you're not be running something like IE6 out of the box (unlike a fresh XP install for example) you should be fine.
As always, it's what you DO on the internet which ultimately effects the security of your system. If you're downloading lots of files from lots of sources and clicking every link that comes your way then you're at a higher risk (of course, if you take the right security precautions you'll be right)
As the others have said, nothing on the internet is technically 100% safe. Mac's are less vulnerable... but by no means invulnerable.
Comment: Note that Safari is not any better than IE6 when it comes to security. Well actually, Safari is worse...
Answer: I have a NAT ADSL connection at home and a 3G service for away. While on 3G I have noticed ssh login attempts which you would not normally see behind a NAT firewall.
Have a look to see what services you are running.
netstat

or
netstat -f inet

Active Internet connections
Proto Recv-Q Send-Q  Local Address          Foreign Address        (state)
udp4       0      0  *.ipp                  *.*
udp4       0      0  172.16.250.1.kerberos  *.*
udp4       0      0  192.168.144.1.kerberos *.*
udp4       0      0  *.*                    *.*
udp4       0      0  localhost.ntp          *.*
udp4       0      0  *.ntp                  *.*
udp4       0      0  *.snmp                 *.*
udp4       0      0  *.*                    *.*
udp4       0      0  *.mdns                 *.*
udp4       0      0  *.*                    *.*
udp4       0      0  *.syslog               *.*
icm4       0      0  *.*                    *.*

This is an abbreviated list of what I am running. You can see snmp and a syslog server  which you probably would not have.
Most services are listening on all interfaces (*.). In my case I should fixup my snmp and syslog to only listed on my local network.
Install nmap http://nmap.org/dist/nmap-5.21.dmg. nmap has lots of different ways to see if a service or port is listening - try out some on your machine, but not on other machines unless you know what you are doing (I certainly don't).
nmap 127.0.0.1

Starting Nmap 4.85BETA6 ( http://nmap.org ) at 2010-06-17 00:09 EST
Interesting ports on localhost (127.0.0.1):
Not shown: 960 closed ports, 32 filtered ports
PORT     STATE SERVICE
22/tcp   open  ssh
88/tcp   open  kerberos-sec
139/tcp  open  netbios-ssn
445/tcp  open  microsoft-ds
548/tcp  open  afp
625/tcp  open  apple-xsrvr-admin
631/tcp  open  ipp
5900/tcp open  vnc

Nmap done: 1 IP address (1 host up) scanned in 6.28 seconds

Try nmap from another machine as well - you will have to install it there as well. Windows and Linux versions are available.
Are there services you don't want running?
In my case, i'm not sure why I am sharing files via samba (139/445) so I'll turn that off.
I can't see how to turn off ipp (631). This is for printer sharing which is turned off.
If I go online and nmap my pppd IP address, the ipp port is closed. This is good and matched the cupsd config file.
I don't need AFP running all the time so I'll turn that off.
I don't need ssh or screen sharing running so I'll turn that off as well.
I now just have these running.
88/tcp   open  kerberos-sec
625/tcp  open  apple-xsrvr-admin
631/tcp  open  ipp

Someone mentioned that most people are behind a NAT firewall. This is probably true if you have a router, but check that NAT is turned on.
But on a 3G service you are directly connected so you should be careful. I haven't been, so this was a good question to make me review my settings.
Other things to do.

Review your appfirewall.log file
If you are technical, try adding some ipfw rules.

Remember, if a service is not running, no one can get in. So the fewer ports that are opened the better.
Answer: It is not safe to put anything on the internet. Having said that, nowadays most people connect to the internet behind a router, which also tend to implement firwalls and whatever else, so you could be using win95 without a hitch.
It all depends on what you do with that computer and if you are only browsing the internet or are serving content. Can't answer anything more specific without further details.


I am about to be a senior in high school and I just have a question about doubling majors, minoring, and getting Phd's

Question: So i am really interested in psychology, law, film studies, and writing. (very different topics) Could i double major in psychology and say political science and minor in film studies and something like English, and then go on to get a Phd in either law or psychology? By the time i get to college i am sure my interests will change and i could go into quantum physics or something else, but i am starting college applications and for some colleges it is smart to have a good answer on your desired major instead of putting down "undecided." I am just very interested to see what graduates think of doubling majors and minors and if it is even a smart decision to do so. thanks
Comment: Savannah-Jane, It's commendable that you are thinking so far in the future so early, but my advice is to stop. Take classes you find interesting, work with professors that have interesting project, meet the people you can only meet at a college campus. When JR year starts, start talking to professors about after college. Ramp up the summer after your JR year. These things will work out. Find someone at your school who can give you good advice, and have fun.  Visit college campuses, and go to the one you feel most at home.
Comment: I think looking so far into the future can be a good idea. For example, if you wanted to be a clinical psychologist, you would need to know that very soon if you wanted to not "lose" a year or two. You need to take courses in your first year so that you can take courses in your second year, and so forth. Also consider what you need to do a job, and not just what to study. For example, to get into certain graduate programs you would need an honours degree with a thesis and not just a regular major (or double major).
Comment: @neo I think that has the making of an answer. I would agree that senior year of high school is probably too soon to be thinking of a PhD.
Comment: Also, people have been known to change majors while in college (gasp!).  What you say on applications now gives them an idea, but is not a lifelong promise to anyone but yourself.  You will be forgiven for changing it.  Also, there are ways to pick up the material without declaring it a second major or minor.  The first priority is to determine what you want to do for the next five years.  Then do it, or find a good reason to change it.  For example, if you know you want to work for a company that hires only double majors, that is a good reason to do it.  I can't think of other reasons.
Answer: Savannah-Jane,
The future is always exciting, especially for someone who has promise. But I would caution you into looking too far ahead and "smell the roses".
You have probably one of the most important decisions you will make in your life right before you; where you will go to college as an undergraduate. That is the decision I would focus on. The questions you are asking now are important to consider when choosing a school; no one with graduate school aspirations wants to attend a college that sends very few people to the types of schools you might want to attend. But, conversely, it would be unwise to make a decision about where you study just because you want to go somewhere else afterword: make sure that you go to a place you love for your 4-5 years. If a school doesn't provide enough undergraduate research opportunities, you can always do a masters degree before your PhD. If your classes are too hard senior year and you can't study for the LSAT, you can find a way to take a year off and apply next cycle. These things are important, but they aren't the most important.
When looking for a college, look for a place you can see yourself living. And studying. And getting drunk Friday nights if you are into that sorta thing. A place where you might fall in love. A place where you can make friends you can trust. Look for that professor that takes a special interest in his students, and work with him or her. When the time comes, bring up graduate school, what you are interested in, and these things will work out. There is always a way to study what you want if you work hard and are curious. There are certainly kids who would do better at a small liberal arts college than a large state school, but the converse is also true. Figure out the differences between those types of experiences.
My very good friend ended up studying computer science in college, but is now getting his PhD in political science. English majors go to medical school. Physicists go to law school. There will be some "general" decisions you will have to make in the beginning, like if you are more science or humanities inclined. It would be very hard for an English major to go into a Physics PhD program, but that's all you really need to know. There is no rush in picking a particular major. Don't try to design your whole life. Leave some things up for chance. Curious minds always remain curious.
Answer: I graduated with a Bachelors of Science, double major in Management and Electrical Engineering.  I did them sequentially, first graduating with a BS in Management in 3 years (I took courses in summers) and then back to the same school for EE (in 18 months, again via summer courses).
The best argument in favor of double majors is that you can develop competency and strength in two fields.  I personally think it's best if the two fields are related, so that your double major creates a hybrid mix.
This combination was an advantage for me in the job market (industry), mostly because it opened more possibilities (companies, and jobs within companies).
I'm a PhD student now (several decades after my BS) in Computational Social Science, which is in the neighborhood of my original degrees.  This gave me a big advantage over other students who had either no background in computer science or none in social sciences.
As for your college applications, it may be fine to list your current ideas for a major, even if it's a double major.  But much more than just listing them, I think it would be vital to explain in your essay why these two majors seem right for you, and therefore what this tells them about you as a person.  Are you especially good at "creative synthesis" across diverse fields?  Have you demonstrated this in the past?  Are you intensely curious and thus you want to start with these majors as an entry point for a path of intellectual/personal discovery?  And what does the preference for these two majors say about your choice of colleges?
It would also be good to avoid giving the impression that you want to go in all directions at the same time like an espresso-crazed humming bird.  (If you are, in fact, an espresso-crazed humming bird, then you might want to get some help and support with that prior to entering college :-)  )
Answer: In high school and the first couple years of college you are allowed to explore different fields and it is easy to change your major. Sometime around the beginning of your junior year you will need to settle on one or two specific fields and enroll in the specific courses needed to obtain a degree in that major. Sometimes it is possible to complete a double major with an extra year of school work. As you get closer to graduation it gets harder to change majors because you already have a significant investment of time and money in the courses you have already completed.
While it is good to be a Renaissance person with many different interests, in today's world you will probably need to be a specialist in one or two narrow fields if you wish to obtain employment in that occupation.
There are some exceptions, the famous astronomer Edwin Hubble completed a law school degree before chucking it all and starting over in astronomy, but that is not usually an option for people who graduate with a mound of student loan debt and a desire to get on with life.
It is not unlike dating, in high school you should be meeting a lot of different people, as you grow older you will probably want to develop a more serious relationship with only one person, but you need to try out a few (or a lot of) different people while you are young before you can decide on "Mr or Ms Right" when you are older.
Obtaining a PhD will require you to choose one extremely narrow field of study and to publish a thesis that represents a piece of original research in which you invent or discover something that nobody else has ever known before. One joke that is frequently heard in academia is that a PhD is "a person who knows everything about nothing", which refers to the fact that you will be a world class expert in a subject that is infinitely narrow. It is not uncommon for different faculty members in a university department to be working and publishing papers in fields that are mostly incomprehensible even to the professor who works across the hall from them.
A PhD is typically preparation for an academic career, which is nice work if you can get it, but academic positions are highly competitive and difficult to obtain. It is also the "license" that you need that will allow you to apply for grant money from government agencies or private foundations to fund the conduct of your research program. Notice that I said "allows you to apply for", not "assures that you will receive" such grants. Unfortunately there are many excellent grant proposals that never receive funding. Your proven ability to obtain money from external funding agencies is the primary thing that universities will evaluate when you apply for a faculty position.
As a result, there are many PhD's working in jobs outside of academia that they could have obtained with a bachelor's degree and a few years of on-the-job experience. There is a serious overproduction of PhD's which has led some academics to talk about the need for "academic birth control" to avoid producing excessive numbers of PhD's. Of course they usually mean that other universities should practice such restraint, not their own institution.
Employers outside of academia may be wary of hiring PhD's for jobs that don't require such a degree out of fear that you are planning to work for them for just a short time until you find the academic research position that you really want. Thus, you may find that a PhD actually limits your job options and the possibility of earning a middle class income in the future.
Answer: Here is MY personal suggestion for a specific approach to planning your education when you have so many different areas you want to study. I assume you will attend college in the U.S. as a full time student (12+ units per semester) so please adjust if that is incorrect.
In your first semester take the following 4 courses if you can:

(1) a class on managing life as a college student (typically these are categorized as Human Development courses but check with your college counselor). These classes are survival skills training for college. Alternatively you could independently study the following textbook while you are still in high-school:
"Becoming A Master Student", Dave Ellis, Cengage Publishing, ISBN 978-1-285-19389-2 (I recommend this specific book because it helped me immensely a long time ago. I am not connected with the publisher or author in any way).
(2) a class in "how to tutor" which oddly enough will teach you about excellent techniques and habits for studying. It will also prepare you to be able to get a campus job as a part-time tutor if you decide you want to do that later on.
(3A) if you need to, now is the time to take "English 101" (it may be called something else Like "English 1" or "Writing 1" but it teaches standard college-level writing). English 101 is typically a pre-requisite for many other classes. Also take any workshops your college offers on writing research papers. Depending on the subject of the class you will need to learn about using MLA, APA, and CMS citation styles. Purdue University's OWL website can be helpful with that.
(3B) if you do not need to take English 101 (ask your college counselor) then take a course that is required for your "general education requirements". These are those fundamental classes every student has to complete in order to graduate, regardless of their major.
(4) take ONE course for sheer fun! This is for helping you deal with the "pressure" of college. Find an introductory course in some creative hobby you have always wanted to try. Enjoy it (because learning should be fun sometimes) and don't stress about the final grade. But do give it your best effort nonetheless.
(5) if by this point you are enrolled in less than 12 units fill in the rest with more "general education" classes (item 3B above).

For your subsequent semesters during years 1 and 2 be sure that 75% of your classes are "general education" classes so you can knock those out of the way. Work with your college counselor to use the other 25% of your classes as a means to explore beginning/introductory courses in the majors you are thinking about. Sometimes an introductory course can reveal information about a subject that can help you decide if that is really what you want to focus your education on.
One Warning: Do not take too many "excess" classes because this will affect your financial aid in the long run.


Best approaches to panning backgrounds when camera angles change

Question: Hi folks, I was working on a short film the other day and came upon a re-occuring situation that I wanted to get your take on.  One of the scenes takes place in a kitchen.  It was raining outside and you could see rain and water dripping off the gutters out the windows so I added some rain and dripping sounds and EQed to make it sound like it was on the other side of a window.  The question is where to pan it?  The first shot is a full 30 seconds and the windows are hard left.  But then it cuts to the other character's POV and the windows are hard right.  Then it jumps back and forth several times.  Automating the panning makes sense, but having the backgrounds jump around with every cut is very distracting.  The director didn't want to call too much attention to the rain so I kept it low and center.  I'm curious what other approaches one might take to this situation and panning of backgrounds in general when camera angles are frequently changing.  The same question could applied to distance perspectives.  What are different approaches to handling sonic perspective when the visual perspective jumps around?
Comment: This is an excellent question, because it can make the difference between a smart and efficient BGz edit versus drastically over-cutting.
Answer: Hi Brendan,
There are no hard and fast answers... much depends on the story and the director. Above all else, sound and the mix MUST serve the story. That means that sometimes panning the bg sounds will be appropriate - other times it should be left alone. By panning the sounds you immediately draw attention to them. If that serves the story - say the sound of an evil character walking in another room searching for our hero - then it would be appropriate. On the other hand, if drawing attention to the element would be distracting (esp. to the director), as in the case of the rain above, you're better off leaving it. Remember, film sound is NOT reality, but "an entertaining perception of reality" (David Yewdall).
Subtle shifts however can be very effective in giving location clues. If you want to hear some great perspective shifts re: rain specifically, check out "Panic Room" - Ren Klyce changes the bg's to wonderful effect when the action changes from the upstairs to downstairs, from the hall to the room and so on...
Comment: In this case I would probably keep it panned center or give it a bit of  equal stereo spread. Generally you could keep it panned somewhat off to one side, assuming the editor is not "crossing the line". In this case, since they are doing that your best bet is to keep it center or equally stereo. I'm assuming they were using the "jump" of having the window change sides as an artistic choice, and not just bad editing.
Comment: By leave it alone do you mean panned center or keep the panning of the original shot?
Answer: I just saw Black Swan the other day and I was impressed by the sound work. One thing I remember was in the scenes where they are dancing in the ballet studio. There was a pianist accompanying them in the room as they rehearsed. The camera tightly follows Portman as she spins dancing around. The piano (which is in mono) is panned to match the movement of her head, so we hear what a dancer would hear during rehearsals. It's great POV sound work and really gets us in the characters head, but it is also distracting in a good way. There's great use of this POV panning in the Hurt Locker and Children of Men to name other examples.
A mono rain against window hard panned to match camera perspective would be really distracting unless it is serving a story point. The idea of using rain recorded at different angles and cutting between them on every shot also sounds distracting to me. I am convinced that the human ear is hyper sensitive to changes in the stereo/surround field; which is probably a survivalist trait which has kept us from getting hit by a car as pedestrians more than a few times in our lives.
If I were looking to create a non-distracting rain on window ambience I would consider a few things:
1) Start with your rain on window panned to match the camera perspective, ideally on an establishing shot which tells us we're in a house and it's raining. Then move it to the center on the next shot and keep it there. Your panned rain serves its purpose of establishing a sense of place and then gets out of the way. I doubt your audience (with the exception of a few sound nerds) will notice that you've given up on perspective after the first shot. I've seen some seasoned sound editors ignore perspective when cutting backgrounds, especially on scenes with rapid picture cuts.
2) Even though the rainy widow might be on the left in the first shot, think about the sound of interior rain. You most often hear it all around you inside. The sound of rain off of the roof, sliding down exterior walls, or slapping off of a surface away from the window. Create a stereo/LCR/quad/surround ambience that matches this feeling, but doesn't pull the ear too far to one speaker. Pan one stereo window recording of rain to the front speakers, and perhaps a more distant rain interior to the surrounds. That way you convey the depth of the space without a bunch of panning. Once you have a nice enveloping ambience, you'll find that you can use additional mono rain sounds (with perhaps a touch of stereo verb or slap) panned here and there to spice it up a bit,
Just my 2 cents. Good luck.
Comment: Totally agree with you on Black Swan - thought the work with the Piano was incredible.
Answer: If you don't want to draw attention to panning movement, you can always put together & predub layers that are effectively a constant perspective/point of view, then on other stems predub subtle elements that follow the cuts/perspectives to varying degrees. Then its a far less confrontational (either/or) scenario to try small degrees of the additional elements. A good mixer will 'feel' where to add such elements so they don't distract or draw attention to but gently support the drama etc...
Comment: I'm glad you mention this Tim, the "feeling" aspect.  Because that's where I usually determine where I park a spotted BGz sound in the edit - it's usually an intuitive, gut reaction and it always stays there to not draw attention to itself, unless for some reason it must be panned elsewhere.
Answer: This website is great, thanks for the valuable information. I figured I would share my thoughts since I have just wrapped up work on a major hollywood film. Although only the sound assistant, I was working directly with the supervising sound editor and learned quite a bit. The question of panning backgrounds came up a lot. It was the first time this post-production house worked with this supervising sound editor and they weren't sure what he wanted. One of my many duties on the film was to keep feeding the supervisor all of our tracks for him to incorporate into the session. So I was present when he was listening to all the work. Generally he never wanted any background tracks panned unless directly necessary for the story to work. Even for FX he found that there was too much excessive panning. There was a scene with an exterior shower that was edited so that the shower was shifting all over the place. One sound editor had meticulously panned each shower element to follow each cut. The effect was very impressive and worked very well, but the supervising sound editor couldn't keep it. It was incredibly jarring no matter how you treated it. In fact, now that I think about it he didn't want any foley panned either.
Answer: In addition to asking my question here, I've been asking other local engineers and paying careful attention to background panning in the movies I've been watching.  I thought I would share what I've found.
  Keeping things panned center is certainly the easiest option and is precisely what I ended up doing in the scenario I first asked about.  Sonsey makes a good point that the approach taken depends on how much attention one wants to draw to the sound in question.  I received an answer from Justin by e-mail which didn't show up here for some reason.  He brought up the idea of having the same background but recorded from different angles (or processed to sound like different angles) and cutting between those.  Another local engineer I talked to suggested establishing a sound and then obscuring it somewhat.  In the example above, with the rain against the window sound, I could have panned my rain hard left like it is in the scene and a little louder to establish it's presence, then snuck it back down and center as the scene begins to cut back and forth from one over the shoulder shot to the next.
   Aside from keeping things panned center and the ideas I just shared, does anyone else have any thoughts on how to handle noises that change location with camera cuts?
Comment: I always keep in mind that if the picture is telling you one thing then the sound can tell another
Answer: I would accurately pan the rain at the start of the scene and have it identifiable, then gently make it quieter and move it to the centre, so that it does not distract from the dialogue.  Once the audience has identified that it's raining you only need the subtlest of cues to remind them that it is still raining.
Answer: if im understanding it correctly, then both the characters are in 1 room and the camera changes according to their POVs and depending upon who is talking. Hence the window on the left or right positions.
In such cases i try to follow realism. Imagine u and i talking in room. We both are hearing the same ambience, which is surrounding us, so it shouldnt jump or pan constantly as the camera angle changes.
For a surround mix, i prefer to duplicate the stereo ambience track and assign to front stereo and rear stereo pair.
for a stereo mix, i'd prefer to keep the ambience stereo, dialogues centred, more emphasis on the dialogues...no matter how the camera moves... as long as the scene is the same, the ambience sound should be the same, is my understand
any comments?
Answer: I would keep it low and center, as well -- there may be other windows off screen that could be bringing in the sound of the rain.
For quick perspective jumps, I hate panning atmos with each cut because it'll become jarring to the viewer.
Answer: For me, it'd depend a lot on how much dialogue is going on and if the rain has anything to do with thematic elements or subtext. In Flags of Our Fathers, when the general is walking on the beach alone, the waves are heavily panned. But little else is going on! In other scenes with a lot of dial or other hard fx action, not so much panning.
Technically, in order to achieve the panning, you would want to use perspective splits. Find the frames where the cuts happen. Then, cut the sound and split it to a secondary track, using overlaps of a frame or so and little fades if it's popping. By doing this, it's way easier to set up panning and levels and keep them consistent for each angle.


What is て form at the end of sentences when it is not a request

Question: I understand that the phrase ごめん、待たせてしまって! means "I am sorry (and regret) that I made you wait". This statement does not look like a request. Why is a て form and not past form た used here?
Answer: This seems to be simply a colloquial rearranging of the usual "grammatical" order

待たせてしまってごめん(ね・なさい)

(see How do you say thank you for or sorry for?)
This happens all the time. Parts of the sentence are left out and put in after the more relevant parts have been said. For illustrative purposes one might take a very simple sentence りんご(を)食べたよ and rearrange it to 食べたよ、りんご.

りんご食べたよ
  食べたよ、りんご
Answer: First, the て form here is the conjunctive form. As in "I made you wait so...". This is sort of an inverted sentence. Like if you said "This is really good...this pizza," instead of "this pizza's really good.
The 待た is not actually past tense, its 待つ in causative form. The つ becomes た and せる is added, so the word is actually 待たせる. Then, in this example, しまう in て form is also added on so you get 待たせしまって .
The causative form of verbs makes the verb mean "to make" or "to let" someone do that verb. You can read more about them at the link below.
http://www.guidetojapanese.org/learn/grammar/causepass
Comment: Sorry my question was not clear, I knew about the causative form but thought that it should have been 待たせたしまった. I corrected my question to make it more clear. Thank you for a detailed reply though.


Why did Arwen have to become mortal to marry Aragorn if they were both half-elven?

Question: I am sure Elrond is half-elven, so Arwen is too.  I recall something saying Argorn was half-elven as well.  Shouldn't half-elves not have to become mortal to marry each other?
Comment: I also would like to add that Aragorn is not Half-elven, but a descendent of Elros an Half-Elven that choose to be a included in the race of Men. Note that Elros was Elrond brother.
Comment: Check out previous questions like [Of Half-elven and mortal life](http://scifi.stackexchange.com/questions/48678/of-half-elven-and-mortal-life?rq=1) or [Why can Arwen decide her mortality](http://scifi.stackexchange.com/questions/31345/why-can-arwen-decide-her-mortality?rq=1), which deal with the issues of half-elves and mortality.
Comment: If we assume that each step in Aragorn's family tree from Elros represents a generation of Aragorn's ancestors, and that Elros was the last ancestor who had a significant amount of Elven blood in him, and that Elros was exactly 50% Elf, then Aragorn is 99 generations removed from a half-Elven ancestor.  Elros' great, great, great grandchild would have been less than 1% elf.  By Aragorn's time, he would be like 1/1,000,000,000,000th elf.
Comment: I found a claim that Aragorn is 64 generations removed from Elros; the point remains the same.  He isn't half-Elf, he is the great, great, great... [pretend I said "great" 59 more times] grandson of a half-Elf.
Comment: If Elrond is half elven then Arwen would actually be three-quarters elven (assuming her mother is a full elf) Not half-elven like her father.
Comment: @WadCheber - I found a claim that Aragorn is 64 generations removed from Elros; the point remains the same. He isn't half-Elf, he is the great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great, great grandson of a half-Elf.
Answer: Saying that someone is "half-elf" is a way of saying that they have an elven parent and a mortal one. Elrond fits into this category (his mother, Elwing, was an elf; his father Earendil was a human). But one is not thereby "half-human, half-elf" - one has to choose between being an elf and being a human:

"... Elrond Half-elven, who chose, as was granted to him, to be numbered among the Eldar; but Elros his brother chose to abide with Men." (Silmarillion chapter 34; page 254 in my edition)

Thus, at the time of the War of the Ring, Elrond is quite definitely an elf. Arwen gets that same choice.
But Aragorn is quite definitely a human; he's a descendant of Elros. Thus, he is going to die; and Arwen makes the choice to die as well, that is, to be under the Doom of Men, in order to be with him. It is only at the very end of her life that she sees what's involved with this and regrets it:

"If this is indeed, as the Eldar say, the gift of the One to Men, it is bitter to receive." (Lord of the Rings, Appendix A, p. 1038 in my edition)

She doesn't seem to ever reconcile herself to it.
Comment: This is mostly correct, but Earendil as the son of Tuor and Idril was definitely Half-elven himself too, and the choice is restricted to the offspring of Earendil and Elwing and only to their offspring; note Manwe's words in the 1937 Silmarillion: "Now all those who have the blood of mortal Men, in whatever part, great or small, are mortal, unless other doom be granted to them...".  So the offspring of Imrazôr and Mithrellas didn't have the choice: they were human and mortal by default.
Comment: The only comment I can see about this is in the Akallabeth: "The Valar indeed may not withdraw the gift of death, which comes to men from Iluvatar, but in the matter of the Half-elven Iluvatar gave to them the judgement; and they judged that to the sons of Earendil should be given choice of their own destiny."
Comment: @TravisChristian - I don't believe that Tolkien ever said so explicitly, but from the evidence it seems that the choice to be mortal is irrevocable for you and and your descendents, whereas the choice to be an Elf can always be changed.
Comment: So why did Arwen get to choose also instead of being bound by Elrond's choice, while the descendants of Elros did not? (Maybe that should be a separate question)
Comment: Thanks; I was going only by LotR and the 1978 published Silmarillion, which are the only books I have and have read closely - I haven't read all of the History of Middle-earth.
Comment: I think that's fairly well answered by the two questions that Avner linked above.
Comment: This answer doesn't really answer the question of *why* Arwen needed to choose mortality to marry Aragorn. It just corrects the supposition that Aragorn was an half-elf and details why Arwen had the ability to choose.
Comment: I agree with Shisa on this, it doesn't answer the question as to why Arwen had to definitively choose mortality in order to marry Aragon. I asked this question in greater dept on another thread pasted below (along with some other burning questions of mine), really hope you guys can help out with an answer. Cheers http://scifi.stackexchange.com/questions/127166/could-arwen-have-married-aragon-without-giving-up-her-immortality?lq=1
Comment: Looking at it metaphyiscally (marriage as the joining of two souls, etc), you could see it as a requirement that the spouses be "compatible" as it were, and that the Valar are able to *confer* the gift of the One to Arwen, but unable to *withdraw* it from Aragorn. (Should you ask how that interpretation applies to Tuor and Idril, I might consider that Tuor's fate had already been decided/altered in anticipation of their union.)
Answer: I doubt she had to; rather she decided to.
There's precedent for a full-blooded (immortal) Elf marrying a mortal, where the Elf retains (or seems to retain) their immortality:

Idril (daughter of Turgon, King of Gondolin) and Tuor1
Mithrellas and Imrazôr

There doesn't appear to be any requirement that an immortal must become mortal in order to marry a mortal; in fact, they can't. Lúthien is the only full-blooded Elf who did this, and she had to die and be reborn. Only half-Elves of the line of Eärendil were given the mortal choice.
Having said that, by all accounts Arwen decided to give up immortality; bear in mind the words she uses when professing her love to Aragorn:

I will cleave to you, Dúnadan, and turn from the Twilight.
Return of the King Appendix A: "Annals of the Kings and Rulers"

And what Tolkien writes in Letter 153:

When she weds Aragorn (whose love-story elsewhere recounted is not here central and only occasionally referred to) she 'makes the choice of Lúthien'
The Letters of J.R.R. Tolkien 153: To Peter Hastings (draft). September 1954

Notably, he frames her choice in terms of Lúthien, not in terms of mortality/immortality. I'll get to why I think this is important in a moment.
The question then becomes: why did she make the choice?
Tolkien's remark above gives one clue; "the choice of Lúthien" is described thus in The Silmarillion:

Because of her labours and her sorrow, she should be released from Mandos, and go to Valimar, there to dwell until the world's end among the Valar, forgetting all griefs that her life had known. Thither Beren could not come. For it was not permitted to the Valar to withhold Death from him, which is the gift of Ilúvatar to Men. But the other choice was this: that she might return to Middle-earth, and take with her Beren, there to dwell again, but without certitude of life or joy. Then she would become mortal, land subject to a second death, even as he; and ere long she would leave the world for ever, and her beauty become only a memory in song.
The Silmarillion III Quenta Silmarillion Chapter 19: "Of Beren and Lúthien"

If we take the Professor at his word, then one of Arwen's motives is revealed: she's so in love that she would rather die than spend the rest of eternity without him.
As well, though there's no evidence she was thinking along these lines, I've commented before that the nature of the Eldar is such that there are practical benefits to not marrying beneath your mortality:

[T]he life and love of the Eldar dwells much in memory; and we (if not ye) would rather have a memory that is fair but unfinished than one that goes on to a grievous end.
History of Middle-earth X Morgoth's Ring Part 4: "Athrabeth Finrod ah Andreth"

But that's perhaps reaching for explanations; I tend to agree with Matt Gutting that she wasn't thinking that far ahead.

1 There's actually in-universe speculation that Tuor was granted immortality, though personally I find it doubtful; I'm particularly intrigued by Tolkien's statement in Letter 153 that "'it is supposed' (not stated) that he as an unique exception receives the Elvish limited 'immortality'"
Comment: See the Appendix A quote in Wad Cheber's answer. That does seem to imply that the mere fact of her staying after Elrond left "meant", for some reason and in some way, that she *had to* become mortal. How does that work with your answer?
Comment: @MattGutting I'm not as confident in that interpretation; I think there's a distinction to be made between "remaining" and "lingering." We're told that Elladan and Elrohir remained "for a while," but we're not told which choice they made, which to me implies that they still *had* a choice. It seems...odd to me that simply remaining in Middle-earth would make Arwen's choice for her
Comment: That is an interesting distinction, which I hadn't thought of. I'll have to ponder some more.
Comment: Regarding Elladan and Elrohir, also note that both Imladris and Lothlorien appear to be abandoned not too far into the Fourth Age. If Elrond's sons became mortal, one would think that there would be some population remaining at those places. The absence of such would seem to imply that they did indeed take ship later.
Answer: As half Elves, Elrond and his brother Elros had to choose between being mortal men or being immortal Elves.  Elros became a man, Elrond became an Elf.

But to the children of Elrond a choice was also appointed:  to pass with him from the circles of the world; or if they remained, to become mortal and die in Middle-earth.  For Elrond, therefore, all the chances of the War of the Ring were fraught with sorrow.
  -The Return of the King, Appendix A, "The Numenorean Kings"

So it isn't that loving Aragorn itself requires Arwen to become a mortal;  staying in Middle-earth after Elrond departs will make her become a mortal.
As for Aragorn being a half-Elf, he isn't.  See the answer to this question to see just how little Elven blood ran through Aragorn's veins.  He  was something like 0.00000000000000000677% Elf.
Comment: It is most likely that this quote doesn't mean that Elrond's children had to leave at the same time as Elrond. Elladan and Elrohir were able to delay their choice even after Elrond left (referenced, I believe, in Letters of JRRT, #153).


When should a wheel be replaced?

Question: I an not talking about upgrading. How do you know when to buy new wheels because the other ones have worn out? How do you tell a wheel is worn out? I can always true a wheel back to true. And nothing is dented, but the maintenance is getting a little more than it should be.
Comment: You can usually make a rim straight, but that is only half the job. Making it round, straight, and leaving the spoke tension balanced *so that it stays round and straight* is the job. My guess is that's what's missing here.
Answer: At some point the spokes become too fatigued and start snapping.
At some point, with rim brakes, the rim wears through until it's no longer stable.
At some point the bearing races in the hub become too worn.
Of these, only the third reasonably demands that the wheel be replaced -- wheels with worn spokes can be relaced, and rims can be replaced without relacing.  But in some cases, especially if more than one of the above problems is looming, it may be more cost-effective to replace the wheel rather than repair it.
And, of course, there's always the case of some sort of actual damage to the wheel -- ripped spoke holes in the flange, bent flange, "taco-ed" wheel where both spokes and rim will need replacing, etc.
Comment: I agree with your options, but not what indicates a reasonable replacement policy. it is almost always more cost effective to replace than rebuild (ignoring possible environmental considerations), since a new rim should be built with new spokes. Only in the case of a user who can build their own, or a very high end hand built wheel is it practical.
Comment: Well, it's quite common to replace the rim without new spokes, and it's reasonably quick and easy to do (and hence not too expensive).  Granted new spokes would be better, but how much better is the question.
Comment: Common, yes. It's also common to never service your bike, to lubricate the chain until it's gathered dirt and turned it in to sludge, and to buy a bike you never ride. But does that mean it is the best or even a good option? Replacing a rim and using old spokes is cutting the life of the new build by whatever mileage was on the original wheel. Which is stupid. If you're going to do a job, do it right. You list spoke fatigue as your first reason why a wheel might be damaged enough to replace. Given that, why would you risk damaged spokes in your new wheel?
Comment: Maybe I just relaced my old wheel, and I'm replacing a rock-dinged rim.  Or maybe it's a brand-new wheel and I'm replacing a rock-dinged rim.  Or maybe I'm just cheap.
Comment: Cheap is not a reason to do a poor job. Nor to recommend that doing a poor job is the *right way* for someone who doesn't know better. As for a dinged rim, sure. But specify that difference in your answer, or stick to the conditions the OP asked about. Or again, you just confuse the issue for those who don't know enough to decide for themselves.
Comment: And filling the pockets of the LBS guy is not a reason to do the expensive thing.
Comment: No, it's not. Doing the job right is. Enough, dude. I'm tired of your attitude, and tired of you treating any recommendation that isn't jury rigged as a rip off. If you just want to argue, bother someone else.
Comment: Well, I'm tired of your attitude that everything has to be perfect (and expensive) or it's not worth doing.
Comment: Doesn't have to be perfect. Just done right. I cut corners, but only where it doesn't matter. And I could care less if something costs 5 dollars or 500, if it does the job well. Trouble is, you don't know the difference.
Comment: Like I said, I'm tired of your attitude.
Comment: I can't imagine replacing the rim without replacing the spokes.  Rims generally cost a lot more than spokes and last longer.
Comment: But relacing a wheel is a lot of labor (and a fair amount of art), while transferring the spokes to a new rim is a quick and reasonably foolproof procedure.
Comment: Relacing a wheel takes readily available knowledge, but is not at all difficult.  The difficult part is the balance, alignment, and truing of a wheel. Which you have to do, new spokes or old. And, if you build a wheel with the old spokes, you will have to rebuild it properly far sooner, since it cuts way into the life and durability of the wheel. It's a bit like changing your oil, but using the old filter in your car. Better than nothing, but hardly the right thing to do.
Answer: There are several reasons why you might need to replace a rim or a wheel.

Crash or impact damage is the most common. This can range from a
tacoed rim, to flat spots or flare impacts. These are usually very
visible.
Spoke fatigue is a mileage issue. As a wheel is ridden, the constant tension and release of stress on the spokes will fatigue the metal until it breaks. You usually see breaks of several spokes in a short period of time. More than 3 spokes in a few weeks, or spokes breaking at the j-bend for little or no apparent cause are signs of this.
Brake wear is caused by the use of a rim style brake over extended periods of time. You literally wear away enough of the metal on the sidewall of the rim that it becomes too thin to support the pressure of an inflated tire. This is rare, because a rim usually perishes from damage first, but it is dangerous, and should be replaced. There are indicator marks on newer rims to tell you this is happening.
There is the possibility that the rim has become fatigued, or that there is small, non-visible damage from previous repairs that prevent the rim from being trued and tensioned evenly. This is most commonly the reason a wheel is replaced. When the rim is trued straight, measure the tension on the spokes (only on the drive side if it's a rear wheel) and if the wheel is round, and straight, but you can't make the tension at least reasonably even, then it will always come out of true quickly. This makes the maintenance load too high for most riders. It is a damaged rim, but in the least visible way.
And last, if there is damage to the bearing races in the hub, then
the wheel will roll rough and have more resistance than it should. The hub should be replaced.

Of course, you can replace a hub, spokes, or the rim individually. If you replace the rim, you should replace the spokes. Why risk building fatigued parts into your new rim? And if you replace the hub, unless the wheel is very new, you should build with a new rim and spokes, for similar reasons. If you can do the work yourself, you will find it cost effective to build a wheel by hand, but if not, buying a replacement wheel (unless it is a high end hand built wheel) is usually more cost effective.
Given your description, I think number 4 is your issue. I'd say time to replace or rebuild the wheel.
I hope that helps.
Answer: Most reasonably new rims come with a wear line. There should be a groove machined into the breaking surface. Once you can no longer see this, the brakes have worn down the rim too much and the rim needs replacing.
Comment: Depends on the wheel. I'd venture that many machine-built wheels are probably cheaper to simply replace, spokes and hub and rim. Better machine-built wheels and handmade wheels? Yeah, I'd replace just the rim on those.
Comment: @user973810 Are you referring to the streak that seems to form on every rim I have that I try to scrub away, but am never successful? If so that is really interesting. I wonder about the accuracy of these lines. To draw a comparison to another product, my razor has a blue strip to tell me when to change it, but I find that I can go well past that and still shave comfortably. Is it the same? Maybe this should be a different question.
Comment: But a rim can easily be replaced without replacing the entire wheel.
Comment: On some rims, especially newer models, there will be a .5mm deep groove machined in the sidewall. When the rim is new, it looks decorative. When the rim is used, it acts as a warning that break wear has removed too much metal from the rim for safety.

When should a wheel be replaced?


Is it ethical for a country to give "refugees" free housing and benefits while many of its own citizens are homeless and starve?

Question: In my European country there are many thousands of homeless starving people. Yet my country takes many thousands of "refugees" from Africa and gives them a free housing and substantial financial pay(which regular citizens don't get).
Nobody ever explains or discusses the morality of this decisions and those who do are being called racist and fascist.
Not considering the political, economical and legal sides of this issue - which philosophy branches/sources can I rely on to argue with others that this is unethical?
Comment: Ethics of moral responsibility to refugees is discussed quite extensively, see e.g. [Parekh's critique](http://www.thecritique.com/articles/moral-obligations-to-refugees-theory-practice-aspiration-2), but you seem to look for an argument with an already reached conclusion. Be careful, moral balancing is subtle, and any general argument of this sort will be fallacious. You can look at [Tugendhat's Moral Dilemma in the Rescue of Refugees](https://www.jstor.org/stable/40971080)
Comment: Welcome to Philosophy SE. While your question is well formed and specific, as written it seems to be leading with an opinion and many questions such as these get closed for that reason. May I suggest that you edit the question and rephrase it along the lines of whether it is ethical for contributors (taxpayers etc) within a nation to expect priority consideration by a government over non-citizens? That would take a lot of the emotion out of the argument and likely attract higher quality philosophical sources.
Comment: You ask "Is it ethical", but are you really posing a question of ethics --in which one is generally asked to evaluate an ethical dilemma-- if you are simultaneously asking how to defend your thesis that something is in your words "unethical"? You may want to reframe the question.
Comment: I think I was the first to vote to close as off topic (I thought it belonged in economics) but please ignore my vote to close because I see now it is not off topic.
Comment: Ethics is the last thing on politicians mind if it ever crosses their minds.
Comment: One word answer. Politics.
Comment: It's a brave question in these PC times. The situation is so difficult I'm not sure about the ethics of it. But from a practical point of view I feel it is a mistake to forget that charity begins at home. It causes resentment and provides a strong reason to oppose immigration. I wish we could discuss these issues more freely in society without all the extremism.
Comment: This presumes the concept of citizenship is even valid. Why does the geographical location of your mother's vagina when you were born have any impact on how other people should treat you? Citizens are no better (and no worse) than refugees.
Comment: You mean you live in a country in which people have to live in the street? And when you ask them they don't claim that they live there out of free will and would rather live in a room?
Answer: If it were not ethical to do this, would it be ethical to put an injured tourist in the hospital at public expense? This something many countries with socialized medicine also do, and it involves providing housing and upkeep to someone in far less need to whom they have no formal obligation.  How about incarceration of non-citizens?  That is public housing, too, and may provide them income.  Most moral systems have room for those two options, even given extensive homelessness.
There are generally different approaches to people newly forced into a situation, who could not expect it, and people who have routinely failed to find a place within a culture.  There are also provisions for temporary arrangements that are expected not to be permanent, even when there are those who have had the opportunity to find a permanent accommodation and failed.
Most of the long-term homeless are not just in need of housing and accommodation, they need solutions to other problems that keep them in their current state.  Unless the state is willing to do a lot more than simply contain and feed them, they repeatedly return to being homeless.
I don't know much about the European equivalent, but this is particularly true in U.S. cities, that have shelters and general assistance measures available, but due to a real inability to relate to the poor in their own context, make them too hard for people with various problems to access.  Many of the long-term homeless here have PTSD, schizophrenia, drug problems, serious self-image issues, limited ability to relate to the concepts behind money and responsibility, paradoxical oppositional behavior, or other problems of living that, overall, medical systems have not learned to properly treat in a complete and humane way.
In fact, again I only know the U.S. population, many of them have purposely simply walked out of permanent housing options because they find those options problematic or because they feel problematic for others in those situations.  There is a difference between a refugee eager to be out of their situation and a woman who may consider herself undeserving of help because of her own mental and cultural issues, and who may find short-term charity acceptable but long-term charity too hard to accept.
Given that, I don't find this a philosophical problem, but one of internal cultural problems and mental health technology.
Answer: Without investigating the whereabouts we usually help the victims who are hospitalized after serious injuries.  Giving first aid is certainly humane. I consider this act as one such thing.  I mean accommodating refugees is ethical.
But the unethical side (Since generosity is an additional quality, here I would like to treat it as non-ethical) I could find is on the free housing and substantial financial pay which regular citizens don't get. My opinion is, since there are many thousands of homeless starving people in your country, the Government. should conduct a referendum before giving such financial help.  But I am not against the immediate financial help they were given for their survival.  If there were few homeless starving people in your country I would consider it as a great act.

which philosophy branches/sources can I rely on to argue with others
  that this is unethical?

Since laws of a country are formulated according to some philosophy, here you can rely only on laws; not on philosophy; especially because this is not fully related to ethics.
[This answer is from a common man's point of view; never from a broad minded man's.]  Since all people are not so generous, wise or like-minded as we think, while solving an issue like this, we should consider the mentality of the common men of that country.  Otherwise it will lead to internal conflicts (emerged from envy) and will affect the refugees adversely (in future).
In a family (for staying):
How should we treat our guests (in a perfect family)?.  See the story from the Mahabharata (given in bold letters) told by The Golden Mongoose.
In a country (for living):
What should a king do to avoid/deal gossips (even though it is about his own family)?  In other words, what care should be taken while handling sensitive issues? The answer to these questions are given in the Ramayana. Though Rama had firm faith in his wife--Sita, he conducted a fire test and also renounced her...just to convince his subjects.
Since your government couldn't accomplish their main duties to the public, at least for an apology, they should conduct a referendum and show their respect/responsibilities towards them.
Answer: Ironically, there are basically at least two diametrically opposed ways one may view the problem of immigration:

Immigrants as brutal conquering forces.
Immigrants as exploited victims of human trafficking.

https://memory.loc.gov/cgi-bin/query/D?hlaw:2:./temp/~ammem_EUm6::

Discussion regarding ethical treatment of societies under conquest:

"The title by conquest is acquired and maintained by force. The conqueror prescribes its limits..."
https://memory.loc.gov/cgi-bin/ampage?collId=llhb&fileName=037/llhb037.db&recNum=399

Introduction of legislation intended to curb human trafficking of emigrants:

Basically, this 1861 congressional bill outlines a proposed prohibition against human trafficking via emigration practices. There is a long history of exploitation of emigrants for cheap labor.
Answer: Ethics and morals are often debated.
Simply put, if your helping someone and not hurting other people then usually we can agree it is ethical behavior.
Understanding there is a scacity of resources can add complexity to the question you proposed.
However, I would make the arugment we live in a world with much abudence. Therefore, if resources are being consumed modestly and helping people it would be ethical.
Most will agree, people do not choose the location of their birth or initial life circumstances are within their control.
Therefore, the geographic location should not define human essential rights. Furthermore, favoring an individual based on a demographic like country of birth is not ethical. We are all human.
You may also consider, that things should not be given freely. To which I would state nothing is free, everything is an investment, and even a baby needs milk from their mom at early stages in life.
Answer: Brilliant question! Although it seems a little close-ended in that you're looking for arguments against. Is that a bias, or are you in a debating team for the 'against' side? :P
Defining the Question
You are talking about ethical dilemmas. Two equally 'bad' choices.
Choice 1: Put resources and money into helping refugees, thus taking away resources from poor families in your country.
Choice 2: Direct all resources into the poor families already living in your country, and leave the refugees to die.
Assumptions
In order to make a purely ethical choice you have to make the following economic assumptions:

That poor families in your country are not poor due to chronic and systemic issues, such as generational issues, lack of education, lack of skills, lack of motivation. Otherwise, the poverty issue is really a different set of issues.
That the solution to poverty in your country is easily fixed with  known and feasible solutions. Otherwise you are just spending money without any guarantee poverty is solved.
That the known solution to poverty requires a quantifiable sum of money that must be all or nothing .. ie. If you only spend half the amount you won't achieve 50% reduction in poverty, you have to spend all of it to make the solution work.
That the money to solve poverty must come from the money used for refugees, and there is no other source of money that should be used to solve poverty, such as money lost in government corruption, government waster, overspending on military, or bailing out banks.

[In reality, we can be fairly certain that existing poverty in your country is either chronic or systemic and cannot be fixed with a quick cash injection. Furthermore poverty and saving refugees are not sum zero to each other. Even if you took all the money used for refugees and directed towards the poverty in your country, it would still not fix the poverty. And you could fix both problems independently of each other. This is the economic answer.]
Ethical Answer
Assuming the only source of money to save the poor is going to refugees instead, the ethical answer would hinge on the following.
Which of these two statements has the moral higher ground:

The life of refugees, who are likely to die or become targets of a lifetime of violence, repression, and crime - but are technically not the responsibility of your state.
The betterment of poor who, already living in a safe and stable world, lack the opportunities, but who are the responsibility of your state.

In other words, which is morally more important: To save the lives of strangers, or improve to the lives of your kin?
Simply put, which do you value more: Life or loyalty?
Personally, I would argue that life has the ethical higher ground than loyalty, and so long as the lives of the refugees do not cost the lives of the poor (or anyone else for that matter), saving the refugees is the more ethically correct approach.
Reasoning
In your question there is nothing that states that providing sanctuary to refugees will worsen the conditions of anyone in your country - only that it may be an opportunity cost for the poor. Bringing in refugees will not make things worse for the poor - they won't notice any change for better or worse. However, the condition for refugees will be improved.
Reality Check
I think the reality of your question, is that you're wrongly equating the poverty problem in your country with the assistance of refugees. This relationship is fallacious and at worst, prejudiced. They are two unrelated problems. While there is a cost of resettling refugees, this usually pays itself off as cheap labour and increased population which economies benefit from. If you are thinking that costs to assist refugees take the food from the mouths of the poor, this is simply not true because all the money in the world cannot save the poor. What reduces poverty is raising the standard of living, which comes from a better economy, which comes from increased productivity. Opportunities for social mobility for the poor and underprivileged occurs with an ongoing effective social security system, which come from higher taxes, which comes from increased productivity. Overall, increased opportunities across the social strata comes from a shift in cultural norms (expectations of work ethic and achievement) and government assistance to education and training for the underprivileged. This is an ongoing long term change that pales into insignificance compared with the costs of resettling refugees.
Answer: Depending on the differences between the already-homeless and the newly-to-be-homeless-refugees-unless-provided-housing that you think matter, you can judge this either way. Therefore the best way to resolve the issue is to list the biggest differences. I can venture a few guesses:

Refugees do not have the right to work, but homeless citizens do.
Homeless have a history with(in) the country and have presumably lost their housing somehow, but refugees are blank slates.
Homeless have other resources that are supposed to help them, that refugees do not have access to, because of the difference in citizenship.
etc.
Answer: Well it all depends on your perspective.
If you look at the immediate perspective then some might argue that the government should serve its citizen first.
But if you look at larger context you might be saving a person or group of people from the low life they were living till now (whose living conditions were much worse than European countries )and trying to give them future.
But my perspective on this is that no country can be perfect , thus the employability rate of a country cannot be perfect. Therefore letting in refugees is good till a point where not more than one third of its citizens are not on streets.


Why is my Ultegra 6600 much noisier when cross chaining compared to my Deore XT M8000?

Question: This has been bugging me for a while. The Ultegra has no visible wear. The chain has no measurable stretch. The Deore is silent even when dirty and not oiled. The Ultegra is much noisier when freshly cleaned and oiled. After a minor crash which resulted in a bent derailleur hanger on the Deore equipped bike, I straightened it without a proper tool (obviously not perfect) and it's still quiet. No crashes with the Ultegra bike. The difference is so big it's not even funny. I know you're not supposed to cross chain but I find front shifting so inconvenient (large paddle throw, slow shifting compared to rear, you know what I mean). I'm looking for the hard facts, what is it that Shimano did that it's improved so much? My guess is 11 speed (more lateral flexibility in the chain) and different derailleur pulley wheels design but I'd like some expert opinions.
Comment: My first suspicion, for cross-chaining noise, is that the chain is rubbing the derailer somewhere.
Comment: I don't know if a fair comparison can be made as presumably the Ultegra has some wear on it. Also chainstay length and chain line differences have an impact.
Comment: @ArgentiApparatus - It can be front or rear.  Rubbing front is more common, but I've seen it with the rear.
Comment: You're comparing a road group with a MTB group, and not disrearding the transmission loss.   Road groupsets are more efficient than MTB groupsets, and a side effect of that is decreased tolerances which will exhibit as cross chaining noise.
Comment: @Argenti Apparatus - no, the Ultegra was fitted by the previous owner and it looks as new, it was old stock I presume.
Comment: @DanielRHicks you mean front derailleur?
Comment: @Daniel R Hicks - no, it's definitely not rubbing
Comment: @Criggie - then that counts as an answer, doesn't it?
Comment: Chainstay length has a huge impact
Answer: I am not sure this is a fair comparison. 6600 ultegra is now three generations old (6700, 6800 and now R8000 come after).
I rode 6600 for many years, rear shifts are still among the fastest out there. But as you noticed cross-chaining was not great.
I moved to 6800 last year. Shifting speed was compatible (I still feel that a well maintained 6600 is faster, but we are splitting hairs), but cross chaining is much better.
When 6600 came out in early 2000s 11-25 was a monster road cassette for climbing. My current road bike has a 12-32 and I would not go back to a smaller cassette unless I was racing cat 1/2 again.
By comparison XT M8000 became available on bikes just a couple years ago so it represents a much newer group set. A lot has changed in intervening years, and Shimano has tweaked their offerings to match market demand/ current trends.
Comment: "monster road cassette for climbing" - yes, I heard that the pros were begging that the mechanics fit those and now 32 teeth cassettes are commonplace. I have a 11-28 with triple front (I know...) and it sucks for the hilly area I live in where 20%+ gradients are not uncommon. I'm partly looking for an excuse to upgrade to a modern drivetrain but I don't ride the road bike as much nowadays to justify it. Also, thanks for the answer, i've always suspected that it's a limitation of the design.
Comment: I don't understand why it took road so long to finally settle on some proper gearing. My first road bike, the smallest chain ring was a 42!!! I used to climb a mountain every day to university on that bike, it probably made the task twice as hard as a result. I eventually switched to a mountain bike back then.
Comment: "I don't understand why it took road so long to finally settle on some proper gearing" - I have a theory: cycling is a fashion and old wives tales-driven sport. Not a fact or science based one but that seems to change. When I look at the gearing used on the bikes from the 60s-80s era I can't believe they were able to finish those HC climbs. It looks inhumane. I guess that when Eddy Merckx said the pros today couldn't carry his suitcase (his words more or less) he was referring to that. Also, am I correct noticing that it was Lance Armstrong that made spinning popular?


How to pose and arrange people in a group shot?

Question: What are good standard poses for group shots of 3 or 4 people and how can I arrange folks so that they don't just look like they're 'standing around'?
Comment: Good question. The classic example is a wedding shot - bride, groom, 4 parents. What can you do with _that_?
Comment: @ElendilTheTall - You can't do anything, it is going to be boring, trust me.
Comment: If you want the standard poses, just look at any complete wedding photography shoot from the past 20 years. You will get lots of ideas, all boring, but all standard :)
Comment: Ah dpollitt, welcome back. I've been advised to pick your brain re. semi-pro wedding photography. Catch you in chat sometime :)
Comment: @dpollit - Standard may be boring, but I want to get a handle on standard while branching out. :)
Answer: Triangles
A classic approach is to arrange people so their faces form triangles.  This is aesthetically pleasing.
Example by "Harriet Bayliss Photography
another Example by ".eti"
Sub-Groups
A technique which is useful when you have lots ( > 4 or so) of people is to arrange them in subgroups, such that each sub-group works on its own, and arrange the sub-groups so that they link together somehow.
Example on Flickr here by "off thedeepend".
Another example, also on Flickr.  This one by "Sadie Collins"
Heads Together
Finally, putting the subject's heads close to each other builds interest.  It makes them look connected.  Here's an example where "Waechor"'s image works because the 3 girls' heads are close/touching.
Good luck.  :)
Answer: Here's a couple of suggestions:

Classic family or work group portrait: Seat a person or a couple and have the rest stand behind and to the sides. The person or couple sitting down will typically be determined by seniority, but other criteria might create interesting dynamics too, so don't just blindly go by the numbers.
Another classic, especially with younger subjects: Have the group jump and photograph them midair with a fast shutter speed and/or a flash to freeze the motion.
With a more lively and dynamic group, you can also experiment with untraditional poses like for example standing one person a feet or two away from the rest of the group, then have the group look at the one person while the one person looks at the camera, vice versa, or other combinations of looking/not looking.
Arrange the group members like a classic band photo. Place the lead person center and front, and have the other persons stand further behind and to the side. Arrange the people in individual poses.
Comment: Some good suggestions there. Can you link to any example shots?
Comment: Dear jumping shots - please go away!
Comment: Sorry, I don't have any group portrait shots that I can share at this time, but that's a good point! I should add a few group portraits to the portfolio :-)


Is there any other opportunity to get the map in Pokemon Yellow?

Question: I started a new game in Yellow. Since I've played it before, I'm not spending as much time exploring and talking to people. However, in my haste to become a Pokemon master, I didn't get the map from Gary's sister! I noticed this near the beginning of Mt. Moon, so I returned home. However, Gary's sister isn't giving away any maps. Are there any other opportunities to obtain a map?
Answer: So, good news bad news. Unfortunately, we have to start with the bad news. You likely won't be able to get the map in any legitimate way if she is not giving it to you now. In Gen I, that is the only way you are able to get it. In the remakes of Red/Green (Blue) in Gen III, you are able to get it later by talking to Celio on Knot Island (one of the Sevii Islands). But since you don't have access to those areas in the original Gen I games, you are out of luck... mostly.
The good news: You can cheat. Well, that is to say, if you have the ability to enter a GameShark or Game Genie code, you can still get it. Most emulators offer this ability natively, so if that is how you are playing the game you're in luck. If not, you would need to get one of these devices for your GameBoy. The codes are:
Game Genie
01051DD3    Changes the item in your first item slot to a town map

Game Shark
01057BCF    Allows you to buy the town map at a PokeMart

Comment: Thanks for the quick answer! I'm going to have to restart anyway, as I attempted to use a glitch to catch rare Pokemon earlier in the game, but I messed something up along the way. It seems everything is going poorly for me this time :P
Comment: An update: I forgot I asked this over a year ago! I did have the map. I was used to the newer games, where you have a Pokenav in the main start menu. The map in this game is an actual item... Also, I didn't have to restart. It just made it so I couldn't battle any trainers in Mt. Moon!


Football yellow cards and red cards

Question: Can a player be given a red card for just 45 second, after which he will be allowed to continue playing again?
Answer: No. A red card means that the player is out for the rest of the game.
In youth football timed suspensions are possible (at least here they are), but they replace the 2nd yellow card and another yellow card after that suspension is no longer possible. Any offense that would lead to one results in a direct red card.
However, there were situations in the past where the red card was a mistake and the referee took it back. In such a case the player is allowed to return to the pitch.

Football yellow cards and red cards