Wood for boarding a loft?

Question: I want to board out my loft - just for easy storage of things like tools, boxes, old clothes, suitcases, small unused furtniture etc (i.e. nothing too heavy). I am wondering what kind of boards to buy for this purpose. Most of the boards I see advertised for doing this are chipboard, but they also vary widely in price. What's the recommended approach considering I want it to last for 10 years or more?
Answer: For occassional storage chipboard or any plywood 1/2" or greater will be fine.  Go to 5/8 minimum if your joists are on 2' centers.
I personally don't agree with the advice to use plywood. Chipboard is fine: it's strong, and it's made using waste materials so it's more ecologically sound to use it where it's appropriate.  It's not appropriate for applications that are exposed to the elements in any way: in those cases plywood is more durable so justifies the 2x cost and the extra environmental impact.
Chipboard does have a strength axis, which you might as well take advantage of it: you want the joists running across the short side, i.e. 5 joists on every 4x8 sheet if the joists are on 2' centers.
Chipboard made for flooring has a tongue-and-groove along the long side.  That's because while the short sides are supported by the joists, the long sides bridge the joists.  Locking a tongue into a groove prevents sagging between the floor joists.  Obviously not a big deal for you storage loft, but if it only costs a few more bucks for the tongue-and-groove I'd get that.  I've only seen that in 3/4" and 1", BTW, so if you get that you'll have a proper floor up there that you could hold a neighborhood dance on.
Answer: My storage attic is just some plywood sheets over the rafters/insulation. Just nailed them right to the ceiling joists. My attic probably isn't as large as your loft but if you're not looking to make a living space out of it the plywood should probably be fine for you.
Answer: As Scott mentioned, plywood will probably be fine.  I just used 1/2 inch plywood in mine.  I would probably recommend you use "real" plywood though rather than the chipboard stuff.  It's a bit more expensive, but also much more durable if you're going to be walking on it.
One thing to think about (that I didn't) is that if you are in a cold climate you'll typically want the insulation in the loft to come up several inches over the tops of the floor joists (assuming blown in insulation here).  If that's the case, you may not be able to attach the plywood directly to the joists without compressing the insulation (which is not good).
Comment: I have just rolled out insulation that is joist height so it's not compressed, but I also don't have the entire attic boarded, just a strip down the middle, but you're right, definitely don't compress the insulation.

Wood for boarding a loft?


Creating Interfaces that Build Emotional Bonds

Question: What are factors in the user experience that lead to users having an emotional tie to an interface, why, and what would be an example of each factor.
Comment: Microsoft's Notepad is great at making an emotional bond. I hate that thing, a lot.
Comment: @Ben Brocka: Your comment reminds me of "[clippy must die](http://www.youtube.com/watch?v=NxcmoLKVd60)"; note: you must have audio to hear the interview... :-)
Comment: Clippy was a breakthrough in affective computing. There's no better way to detect an irate user than by asking if Clippy is onscreen.
Answer: People build emotional ties to almost any interface that they have spent a lot of time using.  Just take a look at people's reactions to almost any change of interface on Facebook or Gmail.
I don't think there are any design factors that make emotional links, like cute buttons or happy colours, though.  It's simply about people having invested time into an interface and learn't to use it.  When you change that, you are to an extent undoing some of their work, and therein lies the emotion.
Answer: People can identify with colors, fonts, shapes, just about anything. The industrial design of Apple products certainly is a classic example of design eliciting deep emotion and attachment, and the work of Dieter Rams preceded Apple by a few decades with the same appeal. On the software side, any well designed game provides instant examples of emotional and compelling interface design.
However, I would argue that interface elements are secondary to actual content and the user actions and tasks of an application in provoking emotional ties. For example, people are not attached to the simple blue button that says Like on Facebook. Rather, users are moved by what that Like button allows them to do - approve and ratify content, photos and links from their friends.
In short, allowing people to connect to basic human desires and psychological drives is what creates a compelling and loyal user experience. The interface is merely the medium.
Comment: My god, the apple design even illicits religion. And I kid you not :https://www.google.nl/search?q=apple+religion&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
Answer: Consistency and ease of use.
When users get so comfortable with your user interface that they can do their work with minimal thought about the tool and maximum thought about their task, they become dependent and attached to that interface.  This can be good and bad.  You may have established a strong connection to your user community and customers, however, it may be very hard to introduce a new (better in your eyes) interface because they are so attached to the old.
Answer: Most people are uncomfortable with any device more complicated than a pencil sharpener.  You may not hear spontaneous design feedback from these people because machines and user interfaces are not the most important things in their lives.  Given a lack of choice, people will figure out a way to accomplish what they need using the tools they have even if they are not delighted by those tools.
It is easy to mistake a fear of change for an emotional bond.  Gaining an adequate mastery of a device can be a painful process. Once achieved, mastery carries with it a degree of certainty; discarding the mastery evokes uncertainty and fear.
What user interface factors lead to an emotional bond?  Ease of use and familiarity.  Fear of new things, whether a new feature or a new device, is diminished when the new thing is like something they already know: if not the terrible, hard-to-use thing that they already mastered, then something else that is familiar to them.
Answer: The simple answer is "Good UX". That means an interface that is highly intuitive, easy and straightforward to use, something people can use without thinking.
Th emotional bond is created, because applications are just useful and helpful. It is like I love my Virgin+ box, because it records stuff I want to watch, and I can do it without thinking. I love my phone (HTC Desire HD), because it is easy to use, and does all of the things I want it to. They both have good UX.
And the point from JohnGB is also important - that if a UX is good enough to draw people in, then people will learn the quirks and peculiarities. At that point, changing it is a negative experience.
Answer: I know we don't have to be talking about a website here, but in order to provide some context, that's what I'm going to assume below.
It's all about psychology.
People don't interact with a website and decide whether or not they are going to have an emotional attachment. Emotions are part of the subconscious, and therefore websites that wish to engage with the subconscious need to appeal in ways that the conscious mind is not even aware of.
The subconscious is processing massively more information than the conscious. It's looking for elements of danger, survival, food, sex. Some cues are going to appeal more than others - especially those that you can identify with or visualise easily.
A website that excites or arouses has a greater chance of being remembered and revisited.
Pictures engage the brain more than words, so pictures that appeal to your interests or desires will seem more attractive and be remembered even longer.
A website with beautiful pictures of luscious food is more appealing than wordy recipes.
A website that either demands or grows commitment from you in some form is in a small way building a relationship with you that means you are more likely to revisit.
If a website does you a little favour - whether it gives you no-strings-attached free shipping, or provides useful free information - is installing in you a sense of indebtedness which the subconscious will feel a need to repay by revisiting again.
We love stories - a website that tells a story is more engaging than one that just gives facts. Pictures and stories - a killer combo.
Websites that allow you to take part in social validation as part of a community or that enable you to feel good about yourself are very powerful at building emotional bonds.
If all this is combined with an appealing design and a great user experience, and you leave the website with a deep sense of satisfaction, then the bonds are surely formed. You'll tell people and you'll be sure to go back. You're smitten!
I thoroughly recommend Neuro Web Design by Susan Weinschenk about the psychology of designing persuasive and engaging websites by especially appealing to the subconscious. 5 minute into to the book. It's not a long book - you can read it in a few hours, but it tells a powerful story - with pictures and most of the above ideas were examined in this book.


Are there any museums in Stockholm for children? (not Junibacken)

Question: I heard about museum near the Stockholm in which children can make some experiments in chemistry, physics and so on, but I completely forgot its name.
Can you help me to find some information about it (in English, if available)?
Are there any analogs of such museum in other European countries?
Answer: I believe you might be referring to Tomtit: http://www.tomtit.se/english/
There's a similar sort of thing that I've been to in Cardiff, the UK, called "Techniquest": http://www.techniquest.org/start/
I've also been to At-Bristol in Bristol, the UK: http://www.at-bristol.org.uk/
I found the following page too which is a list of interactive science centers around the world, I have no idea if it's comprehensive or not: http://www.cs.cmu.edu/~mwm/sci.html
Comment: If you are travelling around Sweden, check out [Universeum](https://www.universeum.se/en/) in Gothenburg.
Answer: Children, discovering and learning about the world around us at The Natural History Museum and Tom Tits (Södertälje). Exhibits explain the wonders of physics, biology and other sciences. Both are technical Museums.
Answer:
Are there any analogs of such museum in other European countries?

In Paris, there are two of them:

Palais de la découverte
Cité des sciences
Answer: Also - Tekniska Museet has an interactive part called Teknorama with lots of fun and learning things to do.
Answer: Another museum that might be interesting for kids (and adults as well) in Stockholm is Skansen (the open air museum). It recreates the way of life in rural Sweden 200 years ago.
Various traditionally dressed craftsmen show their crafts in old historical cabins with historical decor. Crafts widely range: glass-blowing, making cheese, baking, making yarn out of flax, etc. All these processes are demonstrated and explained, and children are able to participate (there might be a line to participate, but it's possible to watch). The bakery sells their pastries directly to the customers, and I was told that the cheese made in Skansen is used in the food that is served in their cafeteria.
In addition there is also a zoo in Skansen.
Answer:
Are there any analogs of such museum in other European countries?

I can recommend Technorama in Winterthur, Switzerland. It is a technology museum with various experiments suited for children but also all other age groupes.


Best way to show a form field group with multiple values?

Question: Something like these:

The button below adds a new group where the user can fill each of the fields. I think that isn't best way to show because the list could be one-to-infinite and the usability is lost.
Comment: Since I can't see the complete form I'm a bit confused of what the names and dates are for? Can you elaborate?
Answer: I'd try to avoid making a form with so many unlabelled fields, as a general rule.
However, if you have to use this, I'd suggest that you
have the default text of each input in each new row be descriptive of the input type.
So instead of 6 empty input fields, have 6 input fields where the value is there, but is grey, not black, to show it is default text.
Input one would have the value "First Name", user two, "Last Name", and so on. You should then use a javascript which clears the default text when the input field gains focus, and replaces it when the element loses focus, if the element has had no text added.
Comment: That would be the `placeholder` attribute...
Comment: The placeholder attribute is a very neat solution, but we don't have sufficient support yet. The pattern is still pretty good though.
Answer: You can repeat the lables-row every n rows.
So in your table head you have a row like "Firstname | Last name | ... " and you repeat this row of labels every, let's say, 25 rows. The user adds new rows, and after adding the 25th row a row of labels (with different visual look) is inserted that repeates the column's content label, thus ensuring that for another screen length of new rows inserted the label for each column is visible.
Comment: Can you explain why this would be of benefit? You may well be right and this is an ideal solution, but we really need more information from you on this one. One-line answers don't really convey any reasoning or descriptions.
Comment: Updated my answer.
Answer: I think puppybeard's answer is good, however the illustration in Mike's answer could be improved upon by leveraging the law of proximity/similarity by placing all of the add/delete actions into the far-right column:

How it would function is clicking the plus button enables the row and adds a new "add row" below.  You could even experiment with not having any editable text box containing a default value, because the "new row" with it's disabled elements with default values would always be directly under new rows.

Depending on your use case and how many rows you think you might have, you might need to take additional steps to help identify the fields, but for up to maybe 10 rows I think this solution would work well.
Answer: It seems like there are two actions (reviewing and adding) users could be doing on this (I could be wrong, so feel free to correct me).
For reviewing existing data, along the lines of kontur's answer, I've used persistent headers with success in long tables (see the first example here http://css-tricks.com/examples/PersistantHeaders/).
For adding new rows, I think puppybeard's answer works the best.
So you could end up with something like this:
Answer: agreed with most of the answers. i would suggest keep it simple and be consistent whatever option you choose. i can think of couple more options for this type of data. you can have Plus button at top or bottom row but make it obvious.
Option 1

Option 2

Option 3:
this option is different where you can make added entries to read only mode. User would be able to edit or delete entry by enabling row for editing.


What are alternatives to a tripod when I can't take one along?

Question: Due to weight restrictions I cannot take my tripod on my next foreign trip. What are the alternatives?
Answer: The Gorillapod range are quite portable tripods, with the added benefit of 'attach anywhere' - at least places you won't get a conventional tripod!
Comment: After my Gorillapod dropped my camera twice (luckily onto soft surfaces), I'm very hesitant to recommend them.
Comment: A leg keeps popping off my SLR Gorillapod and now I don't trust it with anything other than cheap flashes. It also has become much looser over time...
Comment: I own a couple Gorillapods (SLR & SLR-Zoom) and love them.
Comment: Indeed those Gorillapods are great!
Comment: I agree. I have a Gorillapod that I use with my SLR and love it.
Comment: These can also double as flash clamps, though I wouldn't get anything less than the SLR model for this. (I tried getting an original to hold my flash. Didn't work.)
Answer: You can use a monopod as a lighter, but still sturdy alternative. Small legs for the point at the bottom can serve to help steady you, although it's no replacement for a proper tripod.
GorillaPods are an option, as mentioned by others.
I actually like to use a beanbag when I'm tight for space; it turns almost any surface into a usable camera mount.
Comment: I concur ... you can get an inexpensive monopod that's very light and collapse to a around 18" (probably less).
Comment: monopod indeed. The photographer's Swiss Army Knife. Camera support, cane, billy club, and occasional stick to swipe away overhanging branches and cobwebs.
Answer: Several people have mentioned beanbags and such which are nice, if you want to spend a few bucks on a dedicated solution based on the beanbag concept then check out The Pod series of "beanbags with camera mounts".  I have been using one for a few years and they are great and don't take up much room.
Answer: You can fake the tripod with few metres of string. Instructions here.
Comment: interesting idea - never heard of that before
Comment: I have been meaning to try this out for a while. Its so simple, I cant wait to see how effective it is :)
Answer: Perhaps not applicable in all scenarios, but taking sequences of photos as the maximum speed possible in your camera (say around 5 or so frames) can act as a "stabilizer". Out of such a series, one frame tends to be pretty sharp, even at rather slow shutter speeds.
Answer: If you are so weight restricted that even a Gorillapod wouldn't make it, then look for the more stable support you can get reach of that would allow you to place your camera in the approximate position you want to shoot from.
When indoors, tables, chairs and walls are good candidates. When outdoors, look for posts, branches, rocks or other natural platforms.
If your camera allows, lock the exposure (and eventually the focus) before placing the camera on its chosen place. Remember to check if the camera is out of slipping danger.
Also, if your camera has the options for that, turn off image stabilization, turn on the self timer (2 seconds are enough for shots you don't plan to be part of, 10 seconds otherwise), and press the shutter.
It never hurts to take more than one shot on those occasions, just in case. :o)
Comment: My assumption is that the current tripod that Rowland has is a full size one. The Gorillapod SLR (or smaller models depending on the camera) are quite small and light compared to normal, full-size tripods.
Answer: Consider investing in lenses with image stabilisation, or a camera body with stabilisation depending on the brand and type of camera that you use. Even on wide angle lenses I've had good use of my stabilized lenses in places where I could not take a tripod not only because of transport restrictions, but also because of local restrictions on site.
Comment: (re: Restrictions) Like in cave tours. A flash may make the scene boring and a tripod/monopod would get the tour leader to yell at you. But hand-held with auto-ISO and stabilization (and shooting a few shots to pick the sharpest) can yield usable results.
Comment: This idea is not going to work when using longer exposure!
Comment: I've had success up to a full second exposure. How long do you need?
Answer: You can bring a small gorilla pod, or my preference, a little collapsible monopod.  monopods are great because they offer a lot of monitored support, but are quite compact and lightweight.  My mom even bungees hers to available supports and uses the timer mode to take "afk" pictures.
Comment: away from keyboard (meaning not at the tripod)
Comment: can you please define "afk"?  it's an acronym i'm not familiar with...
Answer: If you're going to be hiking, many walking / hiking sticks have a camera compatible screw mount under the handle.
Answer: A beanbag doesn't take too much space in your bag.
Answer: Scott Bourne has recommended using a bean bag as an alternative, and for traveling he takes a bag/sock then fills it with beans/rice/etc. when he gets there.
Answer: I bought a Trekpod this spring, and I like it a lot.  I took it on a 10-day canoe trip to Canada, and I really appreciated a piece of equipment that did double duty.  If you haven't seen one, it's a walking stick of sorts with tripod legs that fold out at the bottom.  It's not quite as stable as a full-sized tripod, so it's more susceptible to swaying in the wind, and it's not as good on uneven ground as a full-featured tripod, but it folds into a very functional walking stick when you're not using it as a tripod.
Most of the landscapes in this gallery were taken on the Trekpod, and I'm certain that most of them wouldn't have turned out due to the long exposures I needed (see some of the sunset pics).
Answer: Just to round out the entries here -- if weight is a concern (and not "nopod" zones), then you'd have to be pretty tight on the limits not to have room for the Zipshot. It's not something I'd use as an everyday tripod, but if you think of it as a stabilizer (you'll need to be hands-on in order to avoid mirror and shutter vibrations) it'll get you a couple of stops you wouldn't have otherwise.
As far as I can tell, the idea came from those collapsible feeler canes for the blind -- it's essentially three of them attached to a mini ball head. It's a bit spindly, no question about it, and you wouldn't want to use it with a heavy lens, but it feels at least as good as the Cullman Magic 1 I used years ago, and at 11oz (312g) and 15" folded it's certainly portable enough.
Comment: FYI – the ZipShot tripod seems to no longer be available. It was owned by Tamrac (maker of photo gear bags), and they appear to have discontinued it.
Answer: I've used a combination of gorilla pod + walking stick with some success (my walking sticks are not equipped with a screw mount) It's a more flexible setup than just the gorilla pod, or just a monopod.
Answer: A new product, HandlePod, may work for your purpose. It is small, light (4 oz.) and can be use where tripods are not allowed. It is a handle topped by a 3-axis rotating camera mount and backed by four rubber feet. Hold it against any available solid object for tripod-like stability. Check it out at www.handlepod.com.
Comment: Welcome to Stack Exchange. Are you associated with the company that makes this product? (That's fine, but disclosure is required. See [the site FAQ on product promotion](http://photo.stackexchange.com/faq#promotion).) Thanks!
Answer: I recently bought a Horusbennu monopod. It weighs 0.9 lbs, and is able to hold my D7000 + 30mm without any issues.
Answer: I've used two things. One is Promaster SystemPRO clamper that comes in different sizes, can be used like a mini pod and clamps onto lots of things. And it can be used for strobes.
Another a low cost and light weight solution consists of a 7/8" washer, nylons string measured to near your floor to eye height, and a small bolt with the same thread as the tripod mount all connected together. You step on the washer, pull the string taunt, and the tension acts like a monopod. Not idea, but super small, light, and easy to make. Here's one: http://petapixel.com/2011/01/26/stabilize-your-camera-for-1-with-a-washer-bolt-and-string/
Google for string, tripod, camera for lots of ideas. I haven't tried this, but here is a variant Cadillac model :) http://lifehacker.com/257008/diy-string-tripod


Does having a long 3.5mm cable degrade audio quality?

Question: I've been looking into mics and I've heard that 3.5mm cables have problems with audio degradation over long distances. How long does the cable have to be before I start experiencing issues?
Answer: Like most things, it depends. There are several factors at play: the impedance of the source, the nature of the circuit (balanced vs unbalanced), the capacitance of the cable, etc.
Ideally you want a low impedance source driving a low-capacitance, balanced circuit.
The impedance of the source is a big factor. A low driving impedance will not be affected as much by higher capacitance (which increases with the length of the cable), so it preserves high frequencies better.
An unbalanced circuit is susceptible to interference like buzz and hum, and the longer the cable the more likely it is to pick up such interference.
A typical 3.5mm cable is unbalanced, so all things being equal it will not perform as well over a longer distance. How long? If there's a source  of interference nearby, even three feet may be too much.
Answer: Jim did a nice job of getting to the gist of the problem.
As far as recommendations, If you are recording to a computer I recommend a USB mic. It converts the analog signal to a digital signal right at the mic, so after that you don't have to worry about interference at all. If you need extra distance, you can buy a USB extension cable and use that without worries of degrading your signal. I've used a decent Samson usb mic. Not for super high-resolution recording, but for the basics, it really does the job well.


Is there a linux distro that uses Jack audio server all the time?

Question: By this I mean a distro that does not use pulse audio at all. So when you are runing programs like miro or mumbles you do not lose audio playback becuase Jack took over the audio stack.
Comment: Just don't install pulseaudio?
Answer: Ubuntu Studio should be what you're looking for. It's a multimedia oriented distro based (obviously) on Ubuntu which uses a realtime kernel and the JACK Audio Connection Kit.
Answer: puredyne is made specifically for multimedia applications based on Ubuntu and Debian Live that can run from a CD or DVD, but it does not automatically start up Jack.
There are several other distros for multimedia production, but as far as I know, none of these start Jack by default, and I do not know the state of development on these distros, so I include these just for completeness:

Musix
64 Studio
dyne:bolic

A different solution would be to tell Pulseaudio to run on top of Jack, if you are inclined to do some editing on your config files: http://trac.jackaudio.org/wiki/WalkThrough/User/PulseOnJack


How do you map the flow of a mobile application? Can you provide examples?

Question: I'm currently working on the IA/UX for a mobile application and as I'm mapping it out it doesn't seem like a traditional site map makes sense nor does a flowchart. Can anyone point me to a good set of symbols that make sense for mapping out all the modal windows
Comment: I'd be interested in a good approach as well. I do it in baslamiq at the moment, but showing the navigation flows doesn't work very well (referencing with numbers and nasty stuff like that).
Comment: What mobile OS are you working on?
Comment: @Phil, Can you share some or direct me to some templates or .bmml for flows?
Answer: In addition to the technique described by Rahul, I've also had success in applying Hagan Rivers' approach of "Application Maps" in certain contexts. Rather than an exact one-to-one representation of each screen, her technique tries to consider how a user "perceives" the flow of an application with regards to the menu system. She also uses the concepts of "hubs" and "spokes", which can handle modal dialog flows very well.
You can read about the basics about this approach at OmniGraffle & the Application Map and LukeW – Application Maps.
For a more detailed description of this technique, you might want to consider getting a copy of the 2010 UIE Web App Masters Tour proceedings (as I did) where she presented this technique in detail.
Comment: You were there too? :)
Comment: @Rahul Unfortunately not, but I purchased the proceedings :-)
Comment: Thanks for the advice on this, I think this is what I've been wanting to do but haven't had the words for it!
Comment: +1 for let me discover Hagan's Application Maps. That is helpful.
Answer: What we do is use a thick sharpie marker to sketch out the various screens in full, then we print/cut them out and tape them up to a wall (often a pane of glass in our office) with arrows pointing from one to the other. The benefits are that now you have the right fidelity to encourage discussion (it's not too detailed, but it's detailed enough to facilitate a conversation) and it's visible in an area where the entire team can see and comment on it. I prefer this method over putting a lot of time into dragging around widgets in a wireframing tool.
The biggest benefit this method has is that complexity becomes visible very early on as you try to place the different screens in logical areas on the wall. If it's too complex, you'll soon notice that you can't figure out where to put them all and still have it make sense. That's an early warning sign that you need to simplify. And simplicity should be a priority when designing mobile user interfaces.
Edit: Just came across UX Sticky Notes. You could try using these in combination with my suggestions above.
Comment: Thanks for the response Rahul, I've been wanting to do wireframing on whiteboards but lack the space until we move our office (this weekend). I'll be sure to create a space for me to do that.
Answer: Give Axure a go. It's got a good balance of symbols for flow diagrams and wireframing to get you started. It should give you enough freedom to display the modal windows how you want. e.g. creating a hybrid flow/wireframe.
In terms of the actual design, I see what you mean. It may be tricky to keep it tidy without using number references, depending on how much you have to say. Good luck.
Answer: Before wireframing, write the title of each step or piece of functionality ("sign up", "log in", "Widget List", "Account Info") on a post it with a sharpie. Then slap those post it's on a whiteboard and start drawing boxes around items to group them and draw arrows to flow from page to page. Snap a digital photo in every configuration to document the process.
Comment: Thanks, this fits in well with the "application maps" technique that Paul mentioned. I think I need to create some whiteboard space for myself so I can work like this.
Answer: If you are developing for iOS: the new Storyboards in iOS5 aren't a complete solution but they sure are better than the old Interface Builder.


Disadvantages of split-prism focusing screens?

Question: I'm considering getting a microprism focusing screen for my Nikon d3000 (specifically, the KatzEye). Hopefully this will help tremendously with manual focusing, but I suspect there must be some disadvantages. What are the bigger issues with using a focusing screen?
Answer: here's a couple of potential disadvantages:
blackout: Split-prism focusing screens tend to turn black in the center with slower lenses (usually f/5.6 or slower, depends on the screen).  Unless you're using a slow lens, or setting the aperture manually, this probably won't be a major problem.
effects on metering: Focusing screens can affect the camera's metering system, especially in spot metering mode.  I haven't found this to be a major problem when I've used focusing screens in the past, but it depends on the camera/screen combination.  Check the katz-eye website for your specific camera, they list the effects of their screen on metering.
visual distraction: The focusing screen breaks up the image in a way that can make it harder to see the final image.
cost: The katzeye focusing screens are expensive.
other issues: There are some other possible issues with split prism focusing screens, like a darker viewfinder and alignment issues, but I don't think they're as likely to be a problem with a katzeye screen.
I've used a couple split prism focusing screens on different cameras and have liked them, but I haven't used a katzeye.
Answer: I have a Katz Eye in my Nikon D200, and while I love it, the issues raised by @walter in his answer are there. Visual clutter is the thing I notice most.
Another potential issue is the risk of damaging your camera. Rooting around in your expensive piece of photographic equipment can a hairy experience.
That said, I consider myself being average when it comes to the do-it-yourself department, and I had no problem changing the screen myself.
Answer: The one issue that the Katz Eye prism should overcome is the blackout problem that occurs at f5.6 and slower apertures in the traditional prisms.
Comment: welcome to photo.stackexchange! Can you tell us more, how does it do that?
Answer: I have a nice collection of manual focus lenses, and my camera has a built-in focus screen swapping feature. So I have the camera brand "precision focus screen". It is a more matte screen without split prisms, but I still get blackening noticeable enough to be annoyed when using a variable aperture lens. So I can only recommend something like that and something even more obstructive like split prism if your camera has interchangeable screens (for easy swapping) like mine and your standard lens is fixed aperture.


Has anyone ever had problems with a 2 day diacetyl rest at room temperature?

Question: Say 70 - 74°F (21 - 24°C) I normally do what the books say and rest somewhere in the 60s but this means brining my fermentation freezer up to that temperature.  I am mostly an Ale brewer so normally this is not a problem as I only have one lager fermenting at a time.  Just curious what other people are doing.
Answer: What you describe is exactly what I do. I move my fermenter from the basement (~50°F) to the study (~70°F) and leave it for 2-3 days before racking it to a keg for the lagering fridge.
Since primary fermentation is done and most of the sugar has already been metabolized, there's little or no danger of creating estery off-flavors from the higher fermentation temp. That's more of a worry at the beginning, when fermentation is first taking off and the yeast are thriving on all the sugar.
Answer: Those temps are not a problem at all for a d rest.


How far apart should nails be when installing baseboards?

Question: I am using a nail/brad gun to install baseboard.  How far should I space the nails?  I want to make sure I hit some of the studs, but don't want to take the time to find exactly where all the studs are, so it seems better to space them a little closer.
Comment: Find 1 stud then measure 16" on center (usually) to hit the rest of them.
Answer: We usually tack the baseboard in place with one nail at each side, and then find the studs with a stud sensor, marking on the baseboard as we go.
Alternately, I would think that every 12 inches would be sufficient. We also caulk the top of the baseboards with paintable latex caulk (which helps with dusting later), and that helps hold the baseboard to the wall too.
With shoe moulding (which I seriously recommend, especially on 2nd stories and pier on beam structures), it doesn't matter since the nails go into the baseboard first.
Answer: If you nail near the bottom, you can usually hit the horozontal boards under the studs in the wall and therefore can put nails anywhere. I would just put them every 16 inches or 2 feet. I would recommend using a stud finder to find the studs to nail near the top of the board. Once you find one stud, you know to look every 16 inches from it.
Answer: It kind of depends on the height of the baseboard. Small stuff you can get by with nailing on the bottom 2X4 along the wall. In that case every 16 to 24"- enough to make it hold tight to the wall without movement. If you have an old house with lots of irregularities in the floors or walls, it will require more attention and that may be another discussion all together.
Large baseboard (like 3 1/4 - 5 1/4" will require also hitting the studs along the way a few inches up. I would hit every 16" on top with about every 24" on bottom as long as you know you are hitting the bottom plate.
Answer: Most of the time when the old base is off you can usually see if there are nails in the bottom of the sheet rock messure those to see if the 16 on center if they are figure how high your trim is the mark ur studs right above where ur caulk will go to cover the mark.


Links and tips for Learning and using scales

Question: Tips and links on learning and using different types of scales will be helpful.
If possible List of scales with songs in which they are used and (artists/types of bands) who uses certain scales to a larger degree will also be helpful.
Answer: The problem with giving examples of scale use by certain artists or certain songs is that most artists don't really think in terms of using particular scales. They may not know the theory in the first place, relying instead on their ear to guide them, or they may know the theory but in practice concentrate on playing what "sounds right". Only when quizzed later, they can offer an explanation of why and how what they played works (usually after spending some time figuring out what exactly they played, in scale terms).
Having said that, there are some general rules of thumb you might find helpful, which stem from the fact that musicians influence each other and that certain musical ideas are more "appealing" than others in a given cultural context. I'll try to break down some of these ideas for you.
First of all, my guess is that around 80-90% of popular Western music is based on either the major scale or the minor scale. Thus if something sounds "lighthearted/happy" it is probably major and if it sounds "dark" or "sad" it is probably minor.
In practice, when playing melodies most guitarists don't even go that far - opting instead to use the minor pentatonic (the minor scale without the 2nd and 6th steps) or the major pentatonic (the major scale without the 4th and 7th steps). The pentatonics are the two most important scales that you should have down, as well as the blues scale (the minor pentatonic with an additional flatted 5th step and - more rarely - also the 7th step).
Since the pentatonics are simplified versions of the major and minor scales, you can always switch between them through adding or removing the relevant steps.
It sounds fine in theory, but how to use scales in practice?
Scales and chords
Most of the time you will be playing scales over chords and you'll notice that some of the notes in each scale sound better over a particular chord than others.
The reason for this is that chords themselves are made up of notes from a scale. Thus, the C major chord is most readily constructed from the C major scale. Let's see how that works:
The C major scale:
C    D    E     F   G    A    B     C
The C major chord:
C   E   G
Thus, the C, E and G notes will always sound good when played against a C chord. Moreover, they will sound good against any C major or dominant extended chord such as Cmaj7, C7, C9, C13 etc.
The same is true for minor chords, so if we take the key of Am, we get:
The A minor scale:
A    B    C     D   E    F    G     A
The A minor chord:
A   C   E
So we can see that A, C and E will always sound good against an Am chord.
Bonus points if you spotted that the C major and A minor scales contain the same notes, but simply start from a different one in each case. The two scales are modes of each other. We'll get to using modes in a bit.
Strong and passing tones
We've seen how any note contained in a chord will sound good against that chord. Notes not forming part of the chord will always sound a bit "weak" (or downright ugly) when stressed against it. For this reason if you intend to emphasise a note over a chord, it will work best if the note is part of the chord.
What about the other notes, that aren't part of the chord? Well, it depends on the note. Sometimes, they can be stressed over a chord and thus change the harmonic sound somewhat - for example, a G note played over an Am chord sounds like an Am7. This is because our melody note sounds like a harmonic extension of the chord and it's fine, as long as that's the sound we're looking for.
Some notes are more troublesome (in C major/A minor it is the F note) and sound awful when stressed against a chord. The way to use these is to keep them as passing tones - notes we play when getting from one strong note to another. When these "clash tones" are kept short, they don't offend the ear.
Harmonised scales and combining scales with progressions
We now know that using scales with chords mostly consists in ephasising the strong notes (those that are part of the chord) and keeping the other notes short as we pass from one strong note to another. Is there some way of taking a chord progression and making sense of it in terms of scales?
Luckily, yes. We've seen how we could form a C major chord from a C major scale and that we could further form an A minor scale by starting on the 6th step of the C major scale and an A minor chord from that. It stands to reason that there should be a chord for every step of the major scale (ditto for the minor scale).
Making chords on every step of a scale is called harmonisation and the way to do this is to take the note from any step, make it the root, skip the next note, make the note after that the third, skip one more note and make the note after that the fifth (see preceeding scale/chord examples).
You end up with a series of chord types which is the same for every major key and a second series which is the same for every minor key:
Harmonised major scale:
Major Minor Minor Major Major Minor Diminished Major
Examples:
C major chords: C, Dm, Em, F, G, Am, Bdim, C
G major chords: G, Am, Bm, C, D, Em, F#dim, G
Harmonised minor scale:
Minor Diminished Major Minor Minor Major Major Minor
Examples:
A minor chords: Am, Bdim, C, Dm, Em, F, G, Am
E minor chords: Em, F#dim, G, Am, Bm, C, D, Em
When faced with a chord progression, try to determine what key it is in (based on what chords are present) and then you'll know what scale to use over it.
Modes
We've seen how the C major and A minor scales share exactly the same notes and differ only in what note we choose as our starting point. We could take any note in a major scale and use that as our starting point - the resulting scale would be a mode of the major scale.
So what are they good for?
If you've looked at any scale/mode books, you'll probably have encountered modes as fingering patterns. The easiest way to use those is to treat them as different positional patterns for major or minor scales. Thus, if you know the A minor scale 5th position 6-string pattern, you might use the 3rd position G mixolydian pattern as a lower extension. You'll still effectively be playing A minor, but you'll be using a different position than the standard fingerings.
The series of modes built on steps of a major scale is as follows:
Ionian (major scale) Dorian Phrygian Lydian Mixolydian Aeolian (minor scale) Locrian
The more clever way of using modes is to use them as substitutions for the major and minor scales, whenever particular notes of the major and minor scales just sound wrong, even when played as passing tones. For example, F is a troublesome note in C major and A minor and tends to clash noticeably. The solution: use C lydian instead of C major and A dorian instead of A minor. Those scales contain F# instead of F and often work better in C major or A minor contexts.
Another reason to use modes is if the chords you're working with don't neatly fit into a key. Say you are playing over a repeating progression of Am C D. The progression is centered on Am, but the D chord is out of key. When you try to play the A minor scale over it, it doesn't sound good at all.
Yep, it's our old friend - the F note - clashing again. The remedy? Use A dorian instead.
Putting it all together
All of the above might be a bit overwhelming, but it is necessary context for what is a fairly easy - if time consuming - task: learning to use scales. Here's how to go about it:

Pick a scale pattern and learn it - fingering patterns for all scales are readily available in tuition books and on the Internet. I suggest you start with major and minor scales and associated pentatonics, later go on to the modes, starting with dorian and mixolydian.
Pick a key and learn the note positions for the key in your scale pattern of choice - thus if you start with C major and the 8th position 6-string box pattern, you should learn the name of each note you are playing anywhere in the pattern.
Learn the chords associated with the key and try to combine them in standard progressions.
For each chord, learn the notes that are part of it and identify where they lie in the pattern you are studying.
Record some chords and play over them - start with individual chords at first, pick out the strong notes and experiment with the weaker ones. Try doing some passing tone runs between or around stressed strong notes. Get a feel for what notes in the pattern sound good when held against the chord. Later experiment with two chords strung together and longer progressions.
Move on to a new scale, pattern or key and repeat.

It is a lot of work, but you'll find that there are shortcuts that stem from the construction of the guitar. For example, once you learn where the notes associated with every chord lie in a major scale pattern, you'll find that if you move the pattern to a new position and key, you'll be using the same fingerings for strong notes of the respective chords in the new key. If you're also paying attention to the note names and thus learning the fingerboard, you'll find it much easier to find the strong notes of any chord whose construction you are familiar with.
Comment: Awesome answer.  The quality of some of the answers here amazes me.  Do you write for a living, Faza?
Comment: Not for a living, no - although I am considering it. However, I do have this little music biz blog that has become a bit noteworthy in some circles. Check my profile for details - I don't want to spam this thread.
Comment: wo man. thanx. really appreciate your answer. :)
Answer: in general you should learn the basics about the 7 modes first. You should know at least two of the modes already: 'standard' major and minor. You can find a good overview of the modes here: http://www.fretjam.com/guitar-modes-2.html and here: http://www.guitarlessons.com/guitar-lessons/guitar-modes.php
Later you can look into more exotic scales like the dominant version of the phrygian mode.
I hope that helps. :)
Comment: thanx. how about the aritists/songs where certain scales are predominant?
Answer: Before learning chord progressions,you have to have clear understanding about scale.Chord progression chart guide can be extremly helpful also.
Comment: Welcome to Music Stack Exchange.  We do have question about chord progressions here, and sometimes as well their relation to scales.  However, the OP's question was just about scales and not about chord progressions, so your answer seems somewhat off target.  You might try re-wording it to make its relation to the question clearer.


google analytics - how to see the name of the pages which has been viewed by certain countries

Question: I want a list of my site pages which has been viewed in any country.
I could not find such option in analytics.
How to do that.
So that i can know the people who view certain pages.
so that i can display content according to that.
Answer: The best way is to go to Content > Top Content (or content drilldown of whatever metric is best for the pages you wish to look at). Click the page you are interested in.
Then underneath "This page was viewed..." you will see a series of dropdown menus. Click the last one to see various metrics you can filter by. Click "Country/Territory" to see the most popular countries that visited that page.
One alternative: from the Top Content page, click the dropdown at the top of the table, next to "Page" and click "Country/Territory". This will list all pages and countries, by popularity. For example:
<code>index.html        United States      999
about.html        United States      888
index.html        Canada             766
index.html        United Kingdom     421
about.html        Canada             123
</code>
Answer: You can create a custom report. In your GA account click "Manage custom reports" then "create new report" under metric add the things you want to measure (visits, revenue, conversion rates etc.) under dimension add "Page title" for the first one then you can drill down under that with "country/territory" "region" or even "city". When you run the report you can see which pages are performing well, then select the page you are most interested in and you will see the stats by country/territory.
If you're looking to filter all reports by a specific country or group of countries you can use the advanced segments.


Disc brakes squeak on Trek mountain bike

Question: I have a Trek 3900 mountain bike with disc brakes, and I just took it out of winter storage to start riding it for the season.
Everything works well, except for one very annoying problem: when I stop the disc brakes make an extremely loud obnoxious squealing sound. Any ideas of what is causing this?
Thanks
Comment: Check your fork for play in the headset. Had that influencing the brake once.
Answer: The easy thing to check is whether the pads have got a little damp while you weren't riding it. The solution there is to ride it a bit. If the noise bothers you try riding with the brake slightly on to heat it up.
Unfortunately that conflicts with the other problem: if there's oil on the rotor you should clean it immediately and avoid using the brake until you can clean it (to avoid getting oil in the pads because they're hard to clean). Wipe the rotor with either disk cleaner or rubbing alcohol and a clean cloth. Keep doing that with new solvent and new cloth until no further dirt comes off the rotor. Then take a quick test ride, using the brake. Ideally pedal hard with the brake on, so you heat the pads and rotor (and also get an idea of whether the brake works). Remember that riding with the brakes on heats up the rotors - be careful touching them immediately afterwards. Wipe the rotor with a clean cloth to remove any pad goop.
If there was no squeal last summer the alignment should be fine. The way to check is to look at the gaps between the pas an rotors. Check from a couple of different angles, the pad should be parallel to the rotor from all angles. If it's not try squeezing the lever - some pads pull slightly off angle when they come off the disk.
If all else fails buy new pads, clean the rotors then install the new pads. Remember that the new pads will need a little running in.
Answer: Check the pads. You just might have some oil or moisture there. Cleaning them with a bit of rubbing alcohol or a specific disc brake cleaner might clear it up for you. Clean the rotors, too. If that doesn't help, you can try replacing the pads, but in my experience if your pads are clean and you're still getting noise from disc brakes, your caliper might need realignment.
Comment: Do you mean caliper needing alignment? Realigning a rotor would be tricky.
Comment: Oops. Yes. I will edit.
Answer: When I had similar problem, I rode to the dealers of my bike and they told me that the reason is my pads. Before, I changed the wheel and made any mistake when I set it back. Workers have eliminated this trouble very quickly and cheaply
Answer: If you do shortish rides 20-40 mins grab a spray bottle and spray the brake rotors very lightly tho. It should stop for that period of time if it doesn't stop then it means your brakes are contaminated.
Comment: Spray the rotors with?


Sunken look in photoshop?

Question: Does anyone know to make a control look sunken into the back ground? Is it some sort of photoshop effect?
I.e., in first button in this interface,
Comment: If you haven't gotten satisfying answer, chances are you are not going to get one, unless you clarify what the 3 answerers didn't get right.
Answer: That's quite a clever combination of effects.
There's a vertical gradient to give the rounded appearance to the button.
The arrows are done using an Inner Glow set to black, with its blend mode set to multiply.
The "sunken" look of the button itself is created using a combination of Inner Shadow (to give a direction to the light source) and Inner Glow black/multiply, as with the arrows, with Spread set close to 100% to give that sharp edge.
Soft and sharp edges on shadows convey information about the size of the light source and the distance of the object from the "shadow catcher." The density of the shadow also affects the illusion of distance; objects close to a surface cast darker, sharper shadows, so you can adjust the apparent height and depth of the button recess by playing with those parameters.
Using Inner Glow might seem counter-intuitive, since it's a "Glow," but only important technical difference between the glow and shadow effects is that the glows are directionless, where the shadow effects are directional and require you to define an angle and height for the light source.
Answer: What you're looking at is basically Letterpress effect, without the letters. There are literally gazillions of tutorials for letterpress all over the internet. You can use them, just replace the text with your gradient shape. Here's a decent video one...
http://tutcandy.com/2009/04/letterpress-emboss-text-effect/
(Typically the effect is a combo of Inner Shadow and Outer Shadow layer effects, with the first set to black and Multiply, and the second set to white and Screen or Normal)
Comment: So sad it became a 404
Answer: Layer Style → Bevel and Emboss for the edge, and a linear gradient for the button itself.

Sunken look in photoshop?


How accurate is the time on a digital clock versus the time on internet clocks?

Question: How accurate is the time on a digital clock versus the time on internet clocks? The internet clocks seem slower than internet clocks. So which is the correct time? What are the most accurate clocks?
Comment: You have a problem with your question, in that you suggest one set is slower than itself. More over, I am not sure what makes ths question suitable for Physics.SE?
Answer: The clocks that you find on websites are delayed a bit between the time that the time is registered until it gets to you. Also, you cannot know if the server time is set properly.
There does exists a timeserver protocol, but a human will not make sense of it. Your best bet is to set your computer clock to sync to a timeserver, then reference your computer clock.
Comment: [NTP](http://www.ntp.org/) has provisions to measure and correct for this.
Answer: There are two parts to the question - how regular are the clocks (is a second always the same) and how close is the reading on the clock to the official time now.
A good digital clock, with reasonably constant temperature is probably good to 1sec/day. That is a second has the same value to within 1/(24*60*60) = 0.001%
An atomic clock can be accurate to 1second in millions of years. Fortunately there are 24 expensive atomic clocks flying over your head broadcasting the time to your GPS receiver. Most internet service providers and cell phone masts also use GPS as the time reference so the time on your cell phone and your computer (if you set auto time sync) are very 'accurate'
Then there is the problem of the delay between a distant clock knowing that it it '12:00' and getting the message to you.  The GPS receiver is the best - the travel time for the signal from the satelite to you is a few millisecs.
For your computer it may take 10s of millisecs for the time message to go over the network and so the system has tricks to try and estimate this and correct for it.
Radio used to be the standard for time signals. At the start of the news the radio would play a series of beeps (the pips) that accurately gave you the start of the hour. Now that the radio signal is digitised, sent over a computer network to the transmitter, recorded by the computer in your radio, decompressed, and then played - there may be a delay of several seconds, so most broadcasters no longer send the time signal
Answer: How about the US Naval Observatory site? I think they give master clock signals (the ones you would get over an "atomic" radio-controlled clock that comes from the cesium clock they use, which is the same one (I think) that the beep signals used to come from. I have an inexpensive radio-controlled clock because I always like to know how much time goes by while I'm doing something that would be better spent doing something else. A battery operated clock works during power outages, if you remember to replace the battery once a year or so.
Comment: Alas the USNO tick and tock servers are no longer publicly available, and [the observatory suggests that you use a tier two server near you](http://tycho.usno.navy.mil/NTP/).


Calculating the right portfolio(position size for each leg) in a Long/Short Strategy

Question: For a Long/Short Strategy, I have two stocks with different volatilities. How can I calculate the right position size for each leg?
*The pair trading is not coming from co-integration but more as a hedge (protection)
Answer: I would concur with Chrisaycock if the volatility between two assets is constant, but because it never is I find there are way better approaches. Generally correlations fly all over the map once things start to become interesting in the market, even for generally highly correlating assets. I would look to generate an algorithm that can determine a range of correlation coefficients within a given standard error at a minimum of xx% of all data points. For example, if your two assets do not correlate within a [0.7..0.8] correlation coefficient range at least 70% of the times (70% of all observations) then you probably deal with a very bad hedging instrument anyway. So, again, as I recommend just pretty much all the time: Before running analyses and tests, think intuitively what you try to achieve. You want to look for a very stable hedge instrument. Obviously all of what I said applies equally to intraday as well as longer frequency data points. No beta in the world will produce the desired/anticipated results if it is not stable, no matter how sophisticated you design your research approach.
Secondly, I would then look to cover the remaining data points and research why correlations broke down during those periods. If you can derive a mathematical relationship you could possibly formulate an approach in which you make adjustments to the hedge ratio through an adjustment in your beta/correlation coefficient.
Thirdly, you may want to "re-calibrate" at an optimal frequency in order to updated regime shifts in volatility/correlations. I could write pages about this approach because I have spent a lot of work on optimizing this approach as part of a bigger strategy.
Those are by far not exhaustive nor did I elaborate but I hope it serves as food for thought to actually first make you acknowledge that any assumption that even hints at constant relationships between assets in most markets is utterly flawed.
Answer: Here is a link to a paper with concrete details of calculating the hedge ratio for your position: http://quanttrader.info/public/betterHedgeRatios.pdf.
Certainly, you want to check that it is reasonable to hedge one position with the other, as Freddy warns. But assuming it is, the paper suggests that using total least squares is better than using ordinary least squares (OLS). It contains R code to implement the calculation.
Answer: Assuming you have the beta of the hedging asset to the original asset, then
\begin{equation}
\mbox{amount}_{hedge} = - \beta \times \mbox{amount}_{original}
\end{equation}
As long as the relative volatility between the two assets is constant, then the beta should do the trick.


polynomial-torus

Question: I am wondering if it is possible to prove (or come up with an explicit example) that there is a polynomial $f ( x,y,z  )$ of degree 8 such that the set $f ( x,y,z  )=0$ is a union of two torri? Any specific proof or example of such polynomial? Thanks
Answer: take a Torus, for example
$$ f_{R,r}(x,y,z) := (x^2+y^2+z^2+R^2-r^2)^2-4R^2(x^2+y^2)=0, $$
Now $f(x,y,z) = f_{2,1}(x,y,z) \cdot f_{2,1}(x,y,z-27)$ is a polynomial which zeroset is a union of two tori.
AB, martini.
Answer: A torus can be defined in $\mathbb{R}^3$ as the zero locus of a quartic polynomial. For a simple example that is radially symmetric about the $z$-axis, the Pythagorean theorem and some geometry tells us that
$$\left(R-\sqrt{x^2+y^2}\right)^2+z^2=r^2$$
is the equation of the torus with major radius $R$ and tube radius $r$ (these terms aren't standard or anything). Some algebra (multiply out, isolate the sqrt, square, etc.) allows us to write this as
$$\left(x^2+y^2+z^2+R^2-r^2\right)^2-4R^2(x^2+y^2)=0.$$
This is a fourth-degree polynomial set to zero. Multiply two equations of this form and we're done.
Answer: For example, $g(x,y,z) = (x^2+y^2+z^2+3)^2-16(x^2+y^2)$ is the equation of one torus centred at the origin, and is a polynomial of  degree $4$.  So $g(x,y,z) g(x,y,z+s) = 0$ is the equation of two tori with their centres separated by by $s$ on the $z$ axis, and has degree $8$.

polynomial-torus


Measurable cardinals under Axiom of Determinacy

Question: I seem to remember reading somewhere that ZF+AD proves that $\omega_1$ and $\omega_2$ are measurable cardinals.
Is that right?
If so, can someone [point me to or give here] a [sketch or proof] of these results?
Answer: An alternative proof for $\omega_1$ goes via the set $D$ of Turing degrees (also known as degrees of unsolvability).  $D$ is upward directed by the ordering $\leq_T$ of Turing reducibility, so the cones $C_d=\{p\in D:d\leq_Tp\}$ generate a filter on $D$.  The axiom of determinacy implies that this filter is an ultrafilter, i.e., that every subset $X$ of $D$ either includes a cone or is disjoint from a cone.  (Proof: Define a game where the two players alternately choose natural numbers, producing an infinite sequence $x$; player 1 wins iff the Turing degree of $x$ is in $X$.  Any strategy for either player, being a function from finite sequences of natural numbers to natural numbers, can be coded as a sequence $s$ of natural numbers.  Any Turing degree $p$ in the cone $C_s$ [pedantically, the subscript should be the degree of $s$] is the degree of some play in which the player who has strategy $s$ uses it, because the other player can play any sequence of degree $p$ and then the overall play will also have degree $p$.  So, if $s$ is a winning strategy for player 1 (resp. player 2), then all (resp. none) of the degrees in $C_s$ must be in $X$.)  So AD gives an ultrafilter on $D$, called the cone ultrafilter.  It's non-principal (because there is no highest Turing degree) and countably complete (because AD implies that all ultrafilters are countably complete --- this follows from the fact that there are, under AD, no non-principal ultrafilters on $\omega$).
To get from $D$ to $\omega_1$, use the function $f$ assigning to each Turing degree $d$ the ordinal usually called $\omega^{CK}(d)$, the first ordinal that is not the order-type of an ordering of $\omega$ of degree $\leq_Td$.  The image of the cone ultrafilter under this map $f$ is again a countably complete ultrafilter, now on $\omega_1$.  It is non-principal because $f$ takes arbitrarily large countable ordinals as values on any cone.
The ultrafilter obtained in this way is actually the same as the club filter mentioned in other answers, but the proof via Turing cones needs somewhat less recursion theory than Solovay's proof (which used Kleene's boundedness theorem for $\Sigma^1_1$ sets).
One can also prove the measurability of $\omega_2$ by projecting the cone filter from $D$ to $\omega_2$ via a suitable map.  (I don't remember right now whether the suitable map sends a degree $d$ to the successor cardinal in $L[d]$ of (genuine) $\omega_1$ or to the next Silver-indiscernible over $d$ after (genuine) $\omega_1$; maybe both of them work.)
Answer: Solovay proved that ZF+AD implies that $\omega_1$ and $\omega_2$
are measurable, in the mid-1960s, but his proofs were not published
at the time. Simpler proofs were given by other people. A proof for
$\omega_1$ may be found in Moschovakis's Descriptive Set Theory,
the 2nd edition of which is available for free here.
Both results are in Jech's Set Theory, 3rd edition, pp. 633--636.
Answer: For $\omega_1$ the argument is as follows:  Consider the filter generated by all closed and unbounded subsets of $\omega_1$. Under AD, this filter is an ultrafilter (this is due to Solovay).  The filter witnesses measurability.
Answer: Like Stefan mentions, under AD every ultrafilter is $\omega_1$-complete. Then the proof that the c.u.b filter on $\omega_1$ is an ultrafilter proof goes through Solovay's game where players play codes for well-orderings. The players choose countable ordinals $\alpha_i$ for $i < \omega$. Player I wins if $\sup\{\alpha_i:i<\omega\} \in Y \subset \omega_1$ for some $Y \subset \omega_1$ over which the game is played.
Answer: For a different proof of the measurability of $\omega_1$ under AD, you could look at Eugene Kleinberg's book Infinitary Combinatorics and the Axiom of Determinateness. He shows it using the strong partition relation  on $\omega_1$(that any function colouring the $\omega_1$-cardinality subsets of $\omega_1$ into 2 colours has a homogeneous subset of size $\omega_1$), showing that the filter of $\omega$-closed unbounded sets of $\omega_1$ is actually a normal ultrafilter. The only issue is that proving the strong partition relation is slightly involved.
P.S. Could someone please tell me how to get the arrow notation for representing partition relations right? I have absolutely no idea. Also, please correct me if I'm wrong above; it's my first post on Math Overflow!


Where can I find reliable entertainment reviews which are targeted for parents?

Question: Is there a reliable, online, place, where I can find reviews for video games, board games, toys and movies which are aimed at parents, especially parents with young children?
Answer: I have recommended Common Sense Media in response to a similar question about movies, and it turns out that they provide similarly high quality reviews for the following media:

Movies
Games
Apps
Websites
TV
Books
Music

They have rankings for age appropriateness, as well for rankings and explanations for specific categories that parents are likely to find relevant. You can search by media type, by age, and more.
Comment: "Common Sense" ratings are available right in Netflix, which is a great feature. They're very thoughtful and detailed.
Answer: The BBFC (British Board of Film Classification) has an extremely good reputation for rating movies, and then explaining WHY a movie is so rated.
They're the ones responsible for the legal rating of British films, and their ratings are like this.

U(c): Universally Acceptable but aimed for a very young audience.
U: Universally Acceptable
PG: Acceptable, but requires parental
approval for young children
12A: 12 year olds allowed in
unaccompanied, or anyone accompanied
by an adult. (not recommended for
anyone below 8)
15: No-one under 15
18: No-one under 18

Their parent-centred website is here: http://www.pbbfc.co.uk/ and they also do an app for mobile.
Answer: I've discovered a lot of new board games and other various content through GeekDad(http://www.wired.com/geekdad/).  It's much more of an active blog than a searchable site with reviews and it contains a lot of content other than what you're asking about, but it's well made and highlights a lot of great things I probably wouldn't have otherwise found.
Answer: I use general review sites for judging if the game is appropriate for my son or not.
Every popular review site I know (metacritic, imdb, boardgamegeek, amazon, etc.) contains information about genre, PG rating, basic description, screenshots (or photos) and so on. This general information normally gives me enough data to decide if the game is appropriate. Moreover, boargamegeek and amazon contain info about appropriate age, which also gives me an idea if the toy or game is too complicated.
If I doubt, I just describe, say, general game plot, show some screenshots or photos and see if it excites my son.


Should you make your choice of gaming location based on the promotions or the players?

Question: I have a few years experience playing in the South Florida area and have over heard several locals make the choice of gaming location based off the promotions the particular casino offers. Personally, I believe this is a sign of a "gambler" not really a poker player. As a real poker player would go where the level of competition is ideal for ROI. But, after considering some of the promotions in the area. It is possible to take down 1 promotion and have a profitable evening without needing to grind out several hours of play. What is the proper way of making a gaming location decision for a person who wants to take a pro player mentality at the game?
Answer: What do you consider a "pro-player mentality" is?
As you mention, ROI is perhaps the most important aspect to consider, if poker makes up a significant part of your income. If you can objectively judge what you gain (e.g. Accessibility, Comfort, Money, Social, etc.) by playing in a particular location, then you may feel that you'd be better off playing there. Even monetarily, when taking up the benefits of a promotion being offered. For example, your opponents may not be as easy to beat but, the gain you receive from a promotion may make up for it.
Being professional just means taking a rigorous, critical look at the information that's available to you and using it to achieve work that is consistently qualitatively superior to that of an amateur. In poker terms, using promotions is similar to "bonus-whoring" and, despite it's name, is a great way to increase your ROI.
Why not use these promotions to your advantage!
Answer: Never play for promotions is my opinion.
The very first thing you need to know about promotions is that they are funded by you the player. Look to the left of the dealers box you will see an extra slot were each hand they take money from your pot to fund promotions.*
There are only two upsides to playing promotions, one you will be fortunate enough to be playing with players stupid enough to think that promotions give them an edge.
Two, you can actually get an occasional upside if you really shop, because poker rooms will put out promotions that are putting the promotion fund in the red, to compete for customers. And sometimes certain progressives are larger than the break even on them, giving you a little EV. (Keep in mind that that little EV on a huge jackpot is not likely to be realized over your life time).
The best way to beat promotions is to never play at the place that takes the extra dollar or two of promotion drop. What promotion drop is, is just another bet. A bet that adds deviation to your bankroll, and takes money off the table, making games generally weaker and more prone to break down.
Promotions also have the downside of modifying play, often just turning games into garbage as they check it down to try and make one hand or the other, slow play aces to get them beat, hurry and fold so we can try to get the promo hand, ad nauseam.
*In Nevada, gaming statue allows taking a promotion drop and stipulates that 100% must be paid out back to players with some other jargon specifying some issues that come with that. I also believe that there is an exception that allows a licensee to retain a small part of the promotion for administrative costs in Nevada (really not sure though). Most regulatory agencies say about the same thing, many do allow taking a percentage, I have heard as much as ten percent to administer the promotion. Some poker rooms are quite liberal with what a promotion is, and fund things like money added to tournaments and I have seen reconciliations to players made from promotion money. Promotion money is one of the most insecure funds in the casino. I mean it is easy to steal a little bit of. I don't steal, but I have seen it done, by really stupid people that did not get caught for a long time. IMHO there is no upside to promotion poker. (The one I saw was the poker room manager writing himself a royal flush bonus once in a while after everyone left. He was caught after a couple of years. He was fired then rehired a few months later)
Some houses do an occasional promotion just out of rake. But that is uncommon and they are just doing it temporarily.
Answer: I think the perspective of "never play for promotions" is way too narrow a viewpoint. It's valid to say that the extra buck in drop is a big drag on your return, but there are other factors that might make up for it.
When you're in a game that involves possible promo cash, you as a thinking player who can modify their game to accommodate the promo will be able to outplay your opponents. You will be better able to understand how optimal strategy changes when you have a $50 insurance policy if your aces get beat, or how much your starting hand requirements should change if the house adds $100 to a pot.  Understanding those changes can give you an additional edge.
But the biggest factor IMO is that if it's a fun room and a lot of outside traffic comes in from the casino floor, those promos will help draw in all kinds of people who have only seen poker on TV. Those are the people you want at the table, and you want them to be having a boatload of fun at the table, and if a few dollars of promo cash or incentives being thrown around in the poker room makes these folks come in and stick around an extra orbit or two, everyone wins.
You need something to loosen people up sometimes, and what can be perceived as free money can definitely do that. And even though it might not be a plus for your bankroll with a given set of conditions, the chances are you'll have more fun at the table and you'll be happier at the end of the night.
So go play at the room offering the promos, but make sure you go while they're having the promo.


Download files with Chrome for Android

Question: Is there a way to download media files directly from the Chrome browser? In the stock Android browser I can long-click a link and select "Save link" to accomplish that, but Chrome doesn't offer that option and opens a media player instead.
Answer: In Chrome, keep your finger pressed on the link, and you will see an option "Save Link".
Hence, the file(s) will be saved in the Downloads folder.
To access it and (perhaps) other folders in the future, I recommend downloading a File Management app.
The best ones are said to be ES File Manager and ASTRO File Manager.
While generally, ASTRO is said to be better, the free version has ads.
Your choice!
Comment: Solution found [here](http://android.stackexchange.com/a/53870/5962).
Comment: The option 'Save link' doesn't appear in the context menu.
Answer: Click on the link and close that tab or go back once it tries to play that media.  Go to your chrome history from the menu and long press the link and save it.
Comment: Very helpful indeed! +1
Answer: Chrome on Android has the "save link" now when long pressing on files (such as media) which when just pressed regularly play the content.
the funny thing was that I thought save link would have copied the url or created a bookmark, not download the file...so your question text helped me :)
Answer: Download an app named Turbo Download Manager.
With one click on the file in Chrome, the option comes for this app. Thus, it downloads the files required.

Download files with Chrome for Android


What is the difference between 别人 and 别的人?

Question: What is there difference between these two expressions, or are they synonmyous?
Answer: There are, in fact, two different words written 别人.
The first is pronounced "biérén" and is a noun. It means "other person (other people)" (另外的人). An example of its use is a sentence like

屋子里只有我和他,没有别人。 Only he and I are in the room, no one else.

The second is pronounced "biéren" (note the neutral tone on the second syllable) and is a personal pronoun. It is used to refer to people other than oneself or the person in question. Dan provides a good example (though I would have used 扔 instead of 丢 -- a native speaker will have to weigh in here); in "是别人丢的", 别人 is a pronoun.
As far as I know, 别的人 can be used in place of 别人 in both cases. Nevertheless, I think 别人 is more common in general, and for some reason I tend to think that 别的人 is more naturally a noun than it is a pronoun.
Answer: I'm not a native speaker, but I think they can be used the same in most cases but in some cases are slightly different.
Same:
Did Tom's brother throw the ball?
不,是别人丢的
不,是别的人丢的
Not same:
Is Tom's brother the same guy who threw the ball?
不,Tom 的哥哥是别的人 (I don't think 别人 would work as well here)
Comment: some maybe 别人 implies an _unknown_ other person?


"No Limit" Versus "Unlimited"

Question: Senior programmer in my team in developing hotel management program and there is something about hotel rooms limit, how many room the hotel can provide to customer. He want to add option to indicate that hotel is sure to welcome any amount of customer and he was asking me that should we use "No Limit" or "Unlimited"
Comment: Unless the hotel is being managed by David Hilbert
Comment: Surely the limiting factor is the number of rooms in the building?
Comment: ...or Sarah Winchester
Answer: Is the number of rooms the hotel can provide truly infinite? If so, you can use either one. But if it is not, then you must hit the limit at some point. Therefore "no limit to the rooms" or "unlimited rooms" would be — what's the word I'm looking for here? — a lie.
I suggest you qualify your statement by saying the number of rooms you can offer is "virtually unlimited," to make clear that this is just advertising-speak, and that if a billion people were to show up one night you would have to turn a few of them away.
Comment: I think that the context of the hotel system implies the context of "limited by availability" and that the terms "no limit" and "unlimited" apply only to *extra* limitations that might be applied to a customer.
Comment: @Unreason: The OP specifically speaks of "hotel room limit, how many room the hotel can provide to customer"; I don't see any indication that other factors are meant to be considered at all, much less in place of that principal condition.
Answer: I assume this is not Hilbert's Hotel, which not only had an infinite number of rooms, but could accommodate infinitely more guests even when already full by some deft room changes.
I suspect this is more of a questionnaire trying to deal with people who do not want to give a limit figure for the rooms.  So you might consider words like any or not stated or unspecified.

"No Limit" Versus "Unlimited"


How to combine vector layer and wms layer based on some constraints?

Question: I would like to group  wms and vector layer together but with some constraints in openlayers. The requirement is, if lets say vector layer 1 is selected then its corresponding wms layer should also be visualized as the merged layer instead of showing two different overlays. I tried to load the wms layer by checking if vector layer is visible or not using changelayer event with evt.property === "visibility". Is there any way I can do the grouping without using events check?
Thanks
Answer: You can use a visibilitychanged event listener to handle hide/show events.
I have created a fiddle (based on this OL example) demonstrating a possible approach, together with an example datastructure to describe required and forbidden layers:
http://jsfiddle.net/hDYu4/
In the example above the zoning layer turns off the building layer whenever it is selected.Try playing with both layers to see the effect in action.
The data structure for expressing conditions could be like the following:
var conditions = { "zoning" : {"requires": [], "forbids": ["building"] } };

and the event listener code that you need to register with each layer:
var working=false;

function visChanged(o) {
if(working) return;

working=true;
if(conditions[o.object.name]) {
    if(o.object.visibility) {
        var requires=conditions[o.object.name].requires;
        for(var i=0, l=requires.length;i<l;i++) {
            map.getLayersByName(requires[i])[0].setVisibility(true);
        }
        var forbids=conditions[o.object.name].forbids;
        for(var i=0, l=forbids.length;i<l;i++) {
            map.getLayersByName(forbids[i])[0].setVisibility(false);
        }
    }
    // add code to handle non vibile case
}
working=false;
}

Note the global variable called working introduced to avoid infinite loops.
Last, this is the event registration code snippet (here layer is a dummy variable, you will have to replace it with your own):
layer.events.register("visibilitychanged",window,visChanged);

Please note that the solution does not handle the initial situation when both layers are on because it would have taken too much time (and left nothing for you to do ;-))
Disclaimer: the code was written quickyl as a POC and does little error checking, but should get you started on the right path.
Answer: you have to customize the openlayers layerswitcher:
- create a datastructure that contains the coupling between a master layer and a slave layer
- create a method where you toggle a layer on or off.
- add the following code to the onButtonClick method (i.e. the method that handles the click event):
a) read the id of the layer that is being clicked
b) fetch its slave layers
c) for each slave layer, trigger a click event by calling the onButtonClick


Books on analytic functions on Banach spaces over a non-Archimedean field

Question: I'm looking for good textbooks on analytic functions on Banach spaces over a non-Archimedean field.
If you know one(s), please let me know.
Answer: One beautiful book is Peter Schneider's Nonarchimedean Functional Analysis, appeared in the Springer Monographs in Mathematics in 2006. A more analytic one (with less emphasis on Functional Analysis and more on Calculus) in Alain Robert's A course in $p$-adic Analysis, GTM 198. But I still think the bible is S. Bosch, U. Güntzer and R. Remmert's Non-Archimedean Analysis, appeared in the Grundlehren der mathematischen Wissenschaften, 261.
Answer: I am not sure why the question is about "analytic functions on Banach spaces". This subject from infinite-dimensional analysis seems never studied in the non-Archimedean setting. Already the p-adic analogs of analytic functions behave quite differently from their classical counterparts.
General monographs on non-Archimedean analysis contain only minimal information on p-adic analytic functions. There are good introductions in the books by Robert and Koblitz. However there are some books devoted specifically to this subject:
Hu, Pei-Chu; Yang, Chung-Chun.
Meromorphic functions over non-Archimedean fields. Dordrecht: Kluwer Academic Publishers. 2000;
A. Escassut, Analytic elements in $p$-adic analysis. Singapore: World Scientific, 1995.
Comment: There is a Bourbaki's volume of the resume of the theory of (possibly infinite dimensional) differential and analytic manifolds over Archimedean(i.e. real and complex) and non-Archimedean fields.
It contains definitions and results but no proofs on the title subject.
Answer: Although they are a little older and Anatoly's remark on general monographs might apply here, maybe A. C. M. van Rooij: Non-archimedean functional analysis and W. H. Schikhof: Ultrametric Calculus still contain helpful information.


Does Battlefield 3 stop you from spot-spamming?

Question: Does the game have a built-in safeguard from spot-spamming (pressing the spot button repeatedly, while aiming in suspicious/distant/smoke-filled locations)?
Answer: It does, however I'm having a hard time finding any official source on it. Other than that all I can offer for proof is first-hand experience and several forums where it is suggested. It seems that you can only spot about once per second. Also if you press the spot button several times within a second, it'll require a few second cooldown time before you can spot again.
I did find a forum thread with a thorough explanation of the spotting function, however it still doesn't relate the information from anywhere official. From my experience it looks correct.
Comment: However, if you aim at an area you think contains enemies, you can often spot them without seeing them. The spot function seems to act like a "cone" - the area spotted expands the farther you are away
Comment: I'll testify to that.  It doesn't explicitly display what the cooldown is, but it does seem to increase if you spam spot.
Answer: I do only play hardcore so things may be different on normal servers:
It has spam prevention. Just try it out by pressing "Q" very often repeatedly until it makes a sound (similar to the one in Half-Life 2 when trying to use something not usable ;-) - it's not very loud, though).
After that there is a cooldown until you can spot again. I'm sorry I don't know the exact numbers for times until prevention is active and cooldown. But it's definitely more than 1 allowed per second.
Answer: I think there is a safe guard against it, but the delay is so small, it doesn't really make that big of a difference. Many players use a macro that auto presses the Q button, making their jobs a little easier.


How do you care for your guitar?

Question: A guitar that is used regularly will sooner or later show signs of wear and tear. How do you best care for your guitar and make sure it stays as good as it is for as long as possible?
Answer: Every once in a while, I polish the main body with a soft cloth to remove dust and smudges.
When changing strings I give the fretboad, headstock and pickup areas a good cleaning.
A can of compressed air is a good idea for removing dust and other gatherings from tight crevices like the gaps between the pickups and body. Make sure you hold it at least 6 - 8 inches away though.
I polish the fretboard with a brand of polish I get from my local music shop called 'FretFast'. You might be able to find something similar.
Occasionally I'll tighten the screws around the guitar if they're coming loose. I tend to find that the jack-socket on my guitars come slightly loose after a year or two, so I tighten that too.
As for scratches and/or chips, I haven't done anything about them on my guitar. I have one particular chip in the paint on the bottom of the guitar near the jack socket. I'be had suggestions to repaint it with nail polish or something similar, but I'm still hesitant.
Comment: Lemon oil on a rosewood fretboard is very good
Answer: I have some basic maintenance regimes I follow based on as-I-play, weekly, and monthly schedules--along with spot fixing any serious problems I come across as I play my arsenal. I feel like the more instruments you own, the less organized you can be on this and therefore the more problems you end up fixing as you go. Wood moves, screws come loose, and strings age--so you ultimately need to at least check the basics on a semi-frequent schedule. Here's my basic run down for electric guitars:
Once or twice a month
Check all of the pickguard screws, pickup rings, jack plates, potentiometer nuts, and tuning machine screws and lugs to make sure they are tight. Takes less than 30 seconds on my Les Paul--and that's the most complicated guitar I own hardware-wise.
If I'm in need of a string change (and I usually am) and the fretboard is nasty, then remove all the strings and hit the fretboard with some naptha (common lighter fluid) to clean the gunk off followed up with some Gerlitz Guitar Honey--which is basically mineral oil. See this question for some more strategies on how to clean your fretboard.
Check the potentiometer travel for all volume and tone pots making sure to listen for any scratching (obviously you'd need to plug the guitar in for this part). Also, make sure all the volume knobs are secured tightly and won't come off through normal use.
Quickly check pickup height with a small precise ruler (kept in my case) to make sure that the pickup screws have not vibrated loose from my constant abuse throughout the month.
Weekly
Check to see if I need to replace strings, and if I do change them out one string at a time. Some people swap them all at once all the time, but I have found that the setup on guitars equipped with Tune-O-Matic bridges are easily disturbed, so I don't like to do this unless I need to clean the fretboard.
Wipe down the entire body and neck of the guitar, paying special attention to nooks and crannies like underneath the strings and the headstock--no polish though. I have had bad experiences with polish in the past, so I simply use a little distilled water and some naptha for the hardware.
After I Play
Wipe down the front and back of the guitar with a soft cloth when I'm done. I also attempt to prolong the life of my strings by wiping those down as well with a separate cloth. My fingers are quite oily, so I can decimate a pack of strings in less than a week if I play frequently.
Humidity and Storage
Relative humidity is important for any wooden instrument because wood absorbs water, so I make sure I have a humidifier handy in the winter months to make sure that my playing room doesn't get too dry. Dryer atmospheres can potentially cause finish damage on nitro-cellulose and polyurethane finished guitars as the wood shrinks. Anywhere from 35% to 50% are good numbers for acoustic and electric guitars. Don't make the mistake of thinking that humidity only affects acoustics though; electric guitars are made of wood too.
Since I have a couple of nice instruments, I usually keep the serious guitars that I'm not playing in their hard case--but cheapies like my favorite Tex-Mex Telecaster are often found propped up against my amplifier for quick access :D.
Answer: I use a sound hole humidifier because of the climate I live in (Lifeguard, in my case), but not everyone will need that.
Answer: I make sure to wipe down the strings, fretboard and body after each practice/playing session. Strings last much longer and sweaty grime does not accumulate on the body and neck. I have never polished any of my guitars (I have an acoustic and a classical) but the bodies are still as shiny as when I first got them! Never skip the wipe-downs!
My bass, on the other hand, gets more attention, as I play it so much more. Besides the wipe-down, I adjust the intonation from time to time and also make sure the saddle height is not too low. I have a set of precision tools that make this quick work. I also have to tighten the strap nut screws often, as those get loose after a lot of playing.
Answer: keep it in its [hard] case when you're not playing it.
Answer: I'm a terrible person - I leave my guitar on its stand next to a radiator when I'm not playing it. This is a bad idea since the constant changes in temperature will make your guitar go out of tune a lot and may damage the glue used in the guitar (my excuse is that my room is small).
Putting your guitar away in a hard case rather than on a stand will help to prevent bumps and knocks (horror story: my friend left her guitar on a stand; it got knocked over and a tuning peg came off) and also prevent it from getting too dirty.

How do you care for your guitar?


How to tackle long hours of boom operation?

Question: If I am supposed to do long hours of boom operation in interviews, is there any technique to tackle the situation so that i can conserve my energy for the rest of the shoot.
Answer: Having swung the boom on 9 feature films, I offer this:
1) Sit down...during scene's and when you're not needed, sit down.  My feet are always the first things that complain.  But don't miss your rehearsals, they are crucial to successfully and painlessly swinging a scene!
2) Learn the correct techniques on holding a boom.  Gently, without force.  Arms shoulder width and straight up (initially this may seem tiring, but after one or two days of this you will find it the easiest way to balance the boom with the least energy being expended).  Literally you want to rest the boom in your hands, not hold it as that chews away at your energy.  Bend your knees ever so slightly because locked knees will become painful too.  Conserve your energy whenever you can.  Move your whole body instead of moving your arms whenever you can - This gives you greater stability and reduces the amount of handling noise on the boom itself.
3) Use your bones.  i.e. lock your arms in such a way that your bones and skeleton take the weight and not your muscles. I personally don't like doing this as I find it impedes your flexibility and ability to quickly adjust the boom for an actors unexpected movement, that being said, sometimes it works depending on the situation.
4) Between takes, rest the boom on your foot (on your toes) and relax your arms and back muscles.
5) Be organized:  Have extra batteries, cables, gaffer tape etc, with you in a belt pouch so you don't have to put everything down and delay the shoot whole you're running off to get something.
6) Keep hydrated:  Sip water (not cool drink) between takes, not in huge gulps as your bladder will get the best of you, but small sips thats will allow your body to keep hydrated and you will conserve energy that way too.
All that being said:  The sound mixer on one of the movies told me:  "When you can serve me a glass of wine on a tray attached to your boom , without spilling a drop, I shall call you a boom swinger."  He did use me on three more movies after that one so I guess I was doing something right in his books!  :)
Happy swinging and above all, enjoy it, you are in a privileged position with great responsibility!
Comment: nice stuff!  the true unsung heroes...
Comment: thanx for the tips
Answer: If the interviews are relatively static you can consider investment in a boom stand that supports the pole for you but still allows you to pivot.
Answer: I find that keeping my arms in the same position helps, I will rest the boom on my head in between takes, it looks daft but it helps me.
I'd also take up a bit of weight training, you just need dumbbells, which you can keep in the house so there is no need to join a gym.
Finally invest in a decent boom pole with good grip, you will find that it is nicely balanced and will help you rotate silently.
If you are doing your job properly you will be so busy concentrating on making sure that you are not in anyone's way, not casting any shadows, not in shot, have a consistent audio perspective, have no movement noise, are minimizing reflections and anticipating responses that you will really not notice the fatigue until you hit your first break.
It takes a while to get used to boom operation but it is worth it.
Answer: Iain and Rene have given two of the tips I would have mentioned, but I've got one other. You may want to look into an articulating boom. I don't know if any company besides K-tek makes them, but they're great if you're working with shorter distances from the subject.
http://www.ktekbooms.com/products.php?id=39
Answer: One thing that makes a huge difference over time is simply keeping your arms as straight up as possible rather than out at an angle -- think of your body as an "H."  This not only helps to prevent premature fatigue but will allow you more lateral movement of the boom without having to move your feet (leaning in and out with your hands closer together moves the mic farther).
Answer: A few things for you:
If it is a sit down interview get a Remote Audio Boom Boy and a C-stand.  If the subject isn't stationary (in a chair) then holding the boom is obviously needed.  Nothing beats being in generally good physical conditional. Like everything in life, the better shape you're in the more energy you will have.
In spite of other responses on here, I would strongly advise AGAINST locking your arms.  You need to be quick and agile with the boom, not locked in.  Also, NEVER hold the boom on your shoulders or head during the take.  Between takes, sure, go for it.  During the take the movement against your coat, shoulder, head, etc can and will transmit through the boom pole and into the mic.  You don't notice it on headphones but when it is magnified through a theater system it becomes a huge problem.
If I am booming and mixing at the same time I am able to move the boom pole using very slight, careful, small movements with my fingers.  The more experience you have the more you will get used to what you can get away with and what you can't.
I chuckle when a director or producer tells me they will just have a PA as the boom op!  I have never, in my 12 years of doing location work, come across a PA who was a good boom op.  I always tell the director/producer that the boom op is like a 1st AC/focus puller.  Would you trust a PA to be in charge of focus?  Nope!
Answer: THANKS to everyone for there comments.......
The only lapels available here are the Sennheiser G3 series.Is it advisable to use them over Sennheiser MKH416 if the interviews are over 1hr.Having said that i would like to add a fact that i have never seen a boom stand(in kolkata, india) and my budget never allows me accommodate a boom guy.
Comment: The G3 series are fine, but keep an eye on which frequency you are using as there are a lot of things that can interfere with radio mics.
Comment: The G3 won't sound as good as the 416, assuming you can get within 12 inches of the interviewee.  What capsules would you be using with the G3?  The stock capsules won't sound nearly as good as a Tram, Sanken COS-11D, or Countryman.  But, in this situation, use both the wireless and the 416!  Pan one left and the other right and make a note of it on the camera log.  The editor can pick which one sounds better for the picture.