Initiate voice recording via Bluetooth dialling in car

Question: I drive a car with a built-in hands-free interface to a Bluetooth phone (it's a Volkswagen Passat).  From the "on-board computer" interface in the dashboard, I can select an entry from my contact list and dial that number to talk to them.
I often find that, as I am driving along, I have a thought that I would like to remember by recording a voice memo to myself.  The only way I know of doing this is to unlock my Android phone, start a voice recording application and hit the record button.  By the time I've typed my pin number into my Android phone to unlock it, this is already very unsafe while I'm driving along, so I don't want to do this!
Is there anyway I can set up my phone such that if I dial some "special" number (#*#*# or whatever) that, when I call it will just record my voice rather than actually dialling an external number?  I could then program this number in to my contacts list and access it via the buttons on the steering wheel of my car.
Ideally, when I hang up the call I'd like it to email me the recording, but that may be going too far...
This would also be useful on the motorbike where the phone is in my pocket, but I can dial numbers (when safe to do so) via the Garmin Zumo 660 GPS.  If I stop at some traffic lights, I can quickly dial a number on the GPS, but I certainly wouldn't have time to take my gloves off, unzip my jacket, take my phone out and run a voice recording application!
Answer: Set up Google voicemail. Call that number and record a message.
Comment: Sadly I can't: Google Voice is only available in the US.


Problem with batch mode Saga Raster Calculator

Question: I have to do a couple of raster multiplications for which the batch mode would save me a lot of time. But the only thing I get are rasters that contain nothing but nan values. If I multiply the rasters one by one without batch mode, it works well. the batch mode also works with the same rasters doing other operations like additions or the gt() command. The Grids product tool shows the same behavior.
Sometimes I also get the alert Oooops! The following output layers could not be open which disappears after restarting QGIS.
To me it seems like that is a bug, is there another easy way to do those operations automatically? Let me know if you need the text from the Log File.
Edit: I know there is another Raster Calculator in GRASS, but to use this one i'd have to import all layers to GRASS which would take me a lot of time as well I fear.
Answer: Ok, I tried around a little more and it only works fine if I select the layers from the file system instead of the open layers table.


Reciting quran in a loud voice when praying alone

Question: Sometimes when I'm praying alone, I like to recite a surah out loud because it helps me concentrate, and because for some reason, it gives me more motivation to recite longer surah's. Am I allowed to do so? Or is it only permissible to recite a surah out loud when in a gama'a?
Answer: It is allowed. Many sahabah used to do it. Prophet Muhammad (SAW) used to listen to the recitation when he (SAW) used to walk in the streets at night.
One night when Prophet (SAW) was walking in front of the house of Abu Musa Ashaari (RA), he (SAW) heard him (RA) reciting during salah. He (SAW) stayed there for a little while to listen to this recitation. The following morning after Fajr, he (SAW) praised Abu Musa Ashaari (RA).

Narrated By Abu Musa:
That the Prophet said to him' "O Abu Musa! You
  have been given one of the musical wind-instruments of the family of
  David."
Sahih Bukhari Volume 006, Book 061, Hadith Number 568.
Comment: @CrescentMoon That is correct for Fard prayers. I strongly believe that the OP was asking about Nawafil. The hadith I quoted also refers to Nawafil, because at the time of Prophet (SAW), *all* men used to go to Masjid for prayers.
Comment: I'd like to add that you can recite aloud only in Fajr, Maghrib and 'Ishaa prayers. In Zuhr and 'Asr you should recite silently.
Answer: Abu Qatadah narrated that : The Prophet (peace be upon him) said to Abu Bakr: "I passed by you while you were reciting and your voice was low." He said: "I let He who, I was consulting hear." He said: "Raise your voice." Then he said to Umar: "I passed by while you were reciting and your voice was loud." So he said: "I repel drowsiness and keep Ash-Shaitan away." So he said: "Lower your voice."(Tirmidhi)
Comment: Please consider that evidences are not self-explanatory and elaborate your answer (see [answer])!
Answer: Allah said in Surah al-Israa 17:110 =
"...And offer your Salat (prayer) neither aloud nor in a low voice, but follow a way between."
So it's not allowed to pray loudly as the ayah prohibits that, and instead Allah tells us to follow a way between loudness and lowness.


My DIY printer only boots when all my endstops are triggered. Why is that?

Question: Recycling a Robin Nano board to build a 3D printer using an old computer PSU (300 W), it only boots on when I have no endstops pugged in at all or if I trigger all the ones I have plugged. At the moment I release them the screen goes off (but the fan of the PSU is still on). Does anyone have any clue about what's going on ?
Comment: Sounds like the endstop switches are shorting VCC to GND when not pressed. I guess the logic board has its own 5V regulator because I imagine the computer PSU would happily melt cabling or weld the switches.
Comment: @R_asidkog your comment is good. It may not be right,  but it is good. I can't upvote it because it is not an "answer". Could you submit it as an answer?
Comment: Welcome to 3dPrinting.SE! What controller are you using? Have you double checked to ensure you've attached everything correctly? Have you tried it without anything plugged in (no endstops or motors)?
Comment: I doubled and tripled check the wiring. When nothing is plugged it goes on properly. Controller board is a Robin nano board.
Comment: I used the nano board previously on a printer with a 24 v psu without any endstops related issues. The nano is supposed to manage both 24 and 12 volts. I doubled checked on the endstops boards to make sure signal, ground and VCC are corresponding.
Comment: In line with @r_ahlskog 's comment - either that or your board is expecting NO switches but yours are somehow N/C switches.
Comment: It ended up I had like super cheap endstops that were actually shorting VCC to GND. Just bought other ones and now it's working Thanks all !
Answer: From your fault description of printer logic board losing power when endstops are released it sounds to me like those endstops are shorting VCC to GND when not pressed. That the fault also goes away when the endstops are unplugged reinforces this.
I guess the logic board has its own protected regulator because otherwise you would be shorting out the power supply and that would also turn itself off after likely causing a lot of damage to the logic board.
Answer: It ended up I had like super cheap endstops that were actually shorting VCC to GND, as suspected by r_ahlskog. Just bought other ones and now it's working fine.
Comment: I'm starting to think that those switches were just wired wrong for your printer. Should I try and edit in that into my answer.
Comment: it is relevant in context qith this question if your endstops are NO or NC. It sounds they are NC.


What is the best way to install a C# windows service that doesn't require running installutil manually?

Question: I'd like to package a C# windows service project so it can be easily installed by anyone without having to use installutil command prompt utility? Is there an easy way to configure a Visual Studio setup project to do that similar to how winforms applications are installed?
Answer: I like to create a install project to get a nice and clean MSI installer, this should help you:
http://support.microsoft.com/kb/816169
And codeproject has a good example too: http://www.codeproject.com/KB/dotnet/simplewindowsservice.aspx
Answer: There are plenty of extra answers in this question.
If the app is for basic users then the MSI is the best way to go.
If it's aimed at techies then I personally prefer apps that can install and uninstall themselves, and can run as a service or like a normal app. The linked question has answers that describe this.
Answer: For completeness sakes I'll summarise http://support.microsoft.com/kb/816169 here.
You need to add a Service Installer class to your service component.  This can then be called by the setup routine to add you service.  You'll need to create a custom action in your Setup project to call it.  The details are in the KB identified.


How do you properly cook cow tongue?

Question: In Mexico, "Tacos de lengua" (cow tongue tacos) are popular, and I've come to love them!  I want to learn to make them in the U.S.  What is the proper way to cook a cow tongue?  I've seen the taco stands remove the skin from the already-cooked tongue before slicing it to serve on tacos.  But what did they do before then?
Answer: Standard prep for beef tongue seems to be: scrub it well and rinse, then soak it in cold water for 2-3 hours.  Heat water to a low simmer (about 200F) and cook slowly for at least an hour per pound.  Preferably cook as long as you can (5-6 hours) to get a more tender result.  When meat is tender and cooked, remove meat and save the broth. Cool the tongue and peel off the outer skin.  The broth may be reduced and added to vegetables and meat to create a richer, meatier taco.
I also found a tongue taco (how is that NOT slang for some sexual act?) recipe.
Personally, I'm also a big fan of cold boiled beef tongue with horseradish sauce.  You can go from the cooked tongue straight to that just by slicing it up. Now I really want to make tongue tacos.
Comment: That's what she said?
Comment: I would love to try tongue taco!
Answer: I've only cooked cow tongue once, so don't pay too much attention to what follows. The tongue should be blanched to remove impurities (slime). Just put it in cold water and bring that to a simmer (as what Bob said, let it soak for 2-3 hours).
Then, change the water, start with cold water and simmer the tongue until done. Add the flavor you want. Check for doneness by sticking a needle in the flesh and there is no resistance.
Remove the skin. I've tried to remove the skin after blanching. No luck, it stuck to the flesh. Try it after cooking.
Cheers.
Answer: Having grown up on a farm in Nebraska I can speak from experience. There is no need to soak or blanch the tongue first. Thoroughly wash it is all you need to do. In a large stock pot add the seasoning you prefer. I use a large onion sliced, 4 or 5 bay leaves, dried oregano, fresh basil, garlic salt and Fiesta fajitas seasoning. Lay the tongue in the stock pot and cover it completely with water, then simmer for 1 hour per pound. Remove the tongue from the stock pot and let cool long enough that you can handle it without getting burned, then skin it. Do not let it completely cool or it will be much harder to skin.
Let cool overnight in the refrigerator and then slice crosswise in 1/4" slices. I prefer it cold on bread and butter with a sprinkling of salt and pepper; delicious! You can also make a sauce of sautéed chopped onions and garlic mixed with tomato sauce. Throw in several slices of tongue, let simmer for 30 minutes, remove from sauce and put on fresh hot flour tortillas (Lengua de Res tacos, pure heaven)

How do you properly cook cow tongue?


Can you add alcohol to chocolate being tempered?

Question: I want to make a tempered white chocolate coating with brandy flavour. Will adding the alcohol ruin the tempering process, or is there another way of going about this.
Answer: There are two issues, both of which make this a bad idea:

You temper chocolate to give it a hard, snappy texture.  Adding any liquid would be counter-productive to this goal.
All normal alcohol has some percentage of water in it (as much as 60%, for example, for a typical vodka).  Small quantities of water will make chocolate seize turning into a grainy, paste-like mess.

If you really want to flavor chocolate that is to be tempered, you should use a pure essential oil.  These have no water, and are used in very small quantities.
Still, the better bet is to flavor the filling or other ingredients in whatever you are making.
Answer: Saj already mentioned seizing. To expand: chocolate is a mix of starch and fat. If you add any liquid capable of hydrating the starch, you have to add enough to hydrate all the starch,. Else  the starch clumps. The minimum amount of water you can add is 27% for milk chocolate and 39% for dark chocolate. I couldn't find numbers for white chocolate, it is very special as it only has cocoa fat and the remainder as fillers. If you add that much liquid, you end up with a thick ganache, not temperable chocolate.
I don't know what you want to cost. If you want to make chocolates, the standard is to put the alcohol in the filling . Even if it is a chocolate based filing, it can have liquid, as these filling s tend to be soft  anyway. Of it is a cake, it is standard to coat  in ganache not tempered  chocolate. In both cases, you can add brandy.


Certreq -retrieve can't find the specified CA

Question: I'm currently writing a Powershell script and have run into a bit of a roadblock.  Basically, the script requests, approves, and retrieves new certificates from our CA using certreq.exe and certutil.exe.
So far, I have the request and approval working fine, but as soon as I try to retrieve the newly-approved cert I get a 'directory name is invalid' referring to the CA.  I'm using the exact same -config string for all the other commands, but it fails on the certreq.exe -retrieve call.  If I remove it, it prompts me to select the correct CA out of a list, of which there is only the one.  I'd very much like to avoid that, as I'm trying to automate the renewal of 450+ certificates and having to sit here and click a button for each one will somewhat defeat the whole point.
Anyone have any ideas?
Thanks.

More info:
Powershell script flows as such:

Create .inf file
Run certreq.exe -new using the generated inf file to create a .req
Run certreq.exe -submit with the generated .req
The RequestID is captured from the -submit command and passed to certutil.exe -Resubmit to approve it
Run certreq -retrieve with the captured RequestID, fails saying it cannot find the CA that was used in both the certreq -submit and certutil -resubmit commands.
Answer: This works for me in PowerShell scripts:
invoke-expression -command "certreq -config `"$OnlineCA`" -Retrieve $RequestId `"$CertificateFileName`" "

Answer: Try using the -config parameter. Please check out the TechNet page for more details on the options included in certreq.exe and certutil.exe.
https://technet.microsoft.com/en-us/library/dn296456.aspx
I know I am too late to answer this, but hopefully this will help someone else.


Safe child seat attachment

Question: I was told by my bike shop that the bike I have can only mount a child seat at the seatpost. My son is 2 and I need a safe child seat for him. I have been having great difficulty finding one that mounts at the seat post online and I am reading that its not the safest if not mounted on the back as well. Any suggestions?
Comment: I would not trust a child seat that mounted only to the seatpost.  It should also tie to the rear axle or the chain stays near the rear axle.
Comment: Related: [Child seat (or rack) at the seat post](http://bicycles.stackexchange.com/a/6253/8), [Toddler bike seat vs. bike trailer?](http://bicycles.stackexchange.com/q/5136/8)
Comment: Check out the Bobike line. I have the front mounted (mini) and it is sweet.
Comment: Just a note as this is old but showing up again: Seatpost mounted child seats are now common.  They don't use a luggage rack, but hardware that's part of the seat
Answer: The conclusions you've drawn from your research are correct. There are racks that are specifically rated for child seats, and they attach to the bike's frame into a pair of rack stays near the seatpost as well as near the rear axle. Any rack rated for touring or hauling heavy loads reliably will use these attachment points at minimum.
A child seat should be mounted on a rack that attaches firmly to the frame of the bike - which usually includes the seat stays near the seatpost. There are racks that attach onto the seatpost themselves, but these are lightweight racks, generally meant for bikes that need a rack only occasionally, or for road bikes without rack braze-ons; such "seatpost racks" are designed for easy removal and attachment, and are not designed to hold more than the weight of a daypack. Mounting a child seat on one of these would be horribly dangerous.
I sincerely hope that you've misunderstood your shop. Attaching a child seat to a seatpost rack would probably break the rack and then harm the child. I suggest avoiding any shop that gave this advice.
But I find it difficult to imagine that even a marginally competent LBS employee would recommend this. Is it possible that what the shop said was to get a rack that attached to the frame near the seatpost, as well as near the rear axle?
Does your bike have attachment points in these locations? from your question, I'm guessing it doesn't, and I'd seriously reconsider and use a trailer instead of a child seat with your bike.
Comment: If the frame for some reason cannot take mounts on the chain stays, then one can tie to the rear axle (with a longer axle installed as needed).  The only reason such a connection would be impossible would be rear suspension.
Comment: @DanielRHicks - Do you mean the sort of axle mount the Old Man Mountain racks use for front suspension forks? I think that would be plenty sturdy.
Comment: Something along that line.  I've never seen that particular mount up close, but from the pictures it should be safe and secure (if carefully installed).
Answer: There are also racks, (good quality, safe racks like this one) which only attach to the seat tube.  NOT the seat post, but the seat tube on the frame.
They are strong, rated to 45kg, and fit most bikes.
Answer: After a few days with no accepted answer I figure I might throw something in that is a little outside the box:
I used a Kelty Child Carrier for my kids until they were old enough to ride their own bikes. Something very similar to this: http://bit.ly/JhWk7J
I used it to go downhilling, trails, actual hiking, skateparks (bowls and some smaller jumps), store, school (I was in school and take them sometimes) and when you get to where you need to dismount, you can leave your bike and keep the kid strapped, VERY useful after they have fallen asleep, then when you get to your destination they have a chair right there and you never had to wake them up for ANYTHING! I modified it with a camelback chest strap to keep the child's shoulder straps together so they wouldn't fall out if slightly inverted. The best part of it was the waist belt, get that strapped right and you dont even notice the kid on your back!! So nice! I gave mine to my brother when he had his first, and he LOVES it too!!
Comment: just went to costco yesterday and saw a Kelty with a full backpack attached to the back! The one I had came with a small pouch about the size of a fanny pack, but these ones had a full backpack compartment behind it!! way jealous! might think about getting another baby just to have an excuse to get one!!
Answer: I bike with two children, now aged 1 and 4, and have tried a number of solutions. A couple specific suggestions for you:
First, some child seats come bundled with their own rack. One of them is the Topeak BabySeat.
Second, heavy duty racks include weight ratings. Old Man Mountain is a respected brand and has a rack in their line rated to carry 70 lbs. Their racks are here. (Beware, it's not cheap!).
My personal experience has been with carrying my kids on a bakfiets, Xtracycle and an electric Yuba Mundo. If you are interested, I have a lot more information and photos about those options on bikes-as-transportation.com. Good luck!

Safe child seat attachment


Is it possible to remove Steam from Plank while running?

Question: is there a way to remove steam from dock but leave it minimized system tray?
Found a topic on it however he didnt explain how he did it https://elementaryforums.com/index.php?threads/steam-x-button-minimizes-to-both-dock-and-the-top-panel.204/
Answer: Yes, it is possible.
You'll need to set the $STEAM_FRAME_FORCE_CLOSE environment variable before run Steam. There's a couple ways to do that. The easiest I found is to add the following to the end of ~/.profile:
export STEAM_FRAME_FORCE_CLOSE=1
Then end your session and log in again. That should do the trick.


Standard deviation in JIRA control chart what does it represent?

Question: Trying to figure out what this represents? If standard deviation is high, does this represent inconsistent productivity?
Answer: The short answer: smaller blue area on a control chart means easier forecasting on that project.

The blue area in the JIRA control chart, is the standard deviation. Standard deviation is a key concept in statistics.  JIRA calculates the standard deviation itself, among a few methodologies that can have been used, JIRA decided that an approach derived from tasks is better than methodologies derived from time. To put it simply, it is calculated by using groupings of 20 tasks.
The lower the standard deviation, the less the team deviates from its "rolling average", and the more predictable team performance on that point of time. This means accurate forecasts while standard deviation/blue area is low/small. While the opposite, high and/or inconsistent standard deviation from its rolling average means that any forecast should be deemed unreliable, a stretched goal at best.
A large standard deviation to the rolling average - could represent inconsistent productivity but this is not necessarily the case. The methodology that JIRA uses to calculate it (see my first point) could be grouping "pears and apples" that would make productivity analysis void.
Answer: Standard deviation is a measure of the spread of the data
As you can see from the Wikipedia article on Standard Deviation:

A low standard deviation indicates that the data points tend to be
  close to the mean of the set, while a high standard deviation
  indicates that the data points are spread out over a wider range of
  values.

In my opinion, higher standard deviation does not necessarily "represent inconsistent productivity". It might just be the nature of the domain. Ken Schwaber noted in his books that complexity in software projects is influenced by requirements, technology and people. If we jump to the conclusion that higher standard deviation (arising from higher complexity) is entirely due to inconsistent productivity (relating to people), we may be overlooking the other two factors.
Also, newly formed teams take time to gel together and arrive at a steady pace of output. See the Wikipedia article on stages of group development.
Comment: But the idea is for it to become consistent overtime?
Answer: In general terms, the standard deviation means deviating from any of the standards defined by Industry standards, or by organization standards, or by your Customer standards and/or by your Project standards.
These standards when set quantitatively is easier to measure. The visual presentation that could help everyone understand is by using the Charts. One of the charts that could represent data statistically is known as Control charts . Control charts help to represent the data pretty clearly. However, there are set of rules that need to followed and to be understood prior presenting the data in the Control chart.
Now your question would be what should I Control? If you unable to comprehend or understand the pattern that is causing the failure, control charts will not help. Rather tools like Fish bone, Pareto, etc. will guide you understand the variables that you need to monitor and control.
For the Control charts, the variables that you could monitor for improving (read as continuous improvement) could be defects, fix cycle, scope creep, design issues, or any other data point that is part of your critical success factors identified by your Customer and by your Project team.
Now, let us move on to the next question:  Why would you need so many standards and how would you measure it in the Control chart? This where the crux is. The Control chart clearly segments the standards into two groups: 1) Specification, 2) Control.
Specification is the limit set by the Industry, your organization, by your Customer. Consider the specification as the guideline. Control is the limit you set for your Project. This could be because you would have tailored many variables based on your project requirement.
Certain organization(s) begin by baselining the data with the Industry specification.  While others will not and will tailor based on their comfort level. There are many such rules here which I will not step into. However, I have been recommending my Clientèle to arrive at the control limit after brainstorming with their team.  Later, baselining the limit after couple of deliverables shall enhance the comfort level of the Project team.
The specification has the min and max level set (boundaries) known as Upper Specification Limit (USL) and Lower Specification Limit (LSL).
For the Control limit (boundaries) set by the Project it is known as Upper Control Limit (UCL) and Lower Control Limit (LCL). Now, you see, it does make sense, right?
When the data gets plotted into the Control chart, it would clearly show the yellow-line and the data points to answer whether the data points are in control or are there any outliers.
Hope you are able to catch the information up until now.

There are three different ways to calculate the standard deviation. I will not get into that. Just keep this in mind. Depending on the software other than the statistically enabled ones (Minitab, SPC, etc), most the product would use average of range.
Now, to your question about Jira Control Charts. Jira follows Agile workflow. The details mentioned above are all meant to be for traditional purists like me who would still bend on these items purely to prove the point. However, I am forced to follow the Agile way (that's where the moolah is…), and the agile purists do not believe in using the Control charts as the manifesto does not recommend to go by Industry standards rather follow the standards of your Client.
So, what does Jira use and how is it used in Jira? Agile follows the Sprint model – the more the releases the better the confidence level (early feedback) of your Client and better profitability for your organization. That's the mantra.
Now, the key variables in Jira shall be the Cycle time. This variable tracks the time taken to close the ticket from the time it is assigned to. Please do remember that if the ticket is reopened, the cycle time increases. This makes sense in terms of Agile. Because Agile talks about only Value and nothing else. Just look at from the Client's perspective. The only question they would ask is what's your time to market? Ah, the cycle time again. You see, the point here?
The next metric used is to produce in the Control chart is Rolling average. The rolling average is based on the average cycle time at every key point; wait time . This also makes sense. Because this will highlight on how long does an issue waits to get resolved. Wow! It is easier to monitor and track the outliers.
The next is your data point – standard deviation. This just paints the picture to show how much the project deviates from the rolling average. Do you understand now?
This means, never worry about standard deviation when using it in Agile as productivity measure, rather understand the cycle time, understand how the rolling average is. Later apply the techniques to control these measures. As simple as that.
However, this measure (standard deviation) can also be used to predict your teams confidence in producing the shippable software - not productivity. Never get into productivity here, it will not answer your question.
Long story short, Standard deviation = Confidence level and not Productivity. How confident is your team to produce shippable software? How much X times will it deviate from normal cycle time? Questions such as these and many such more can have a clear answer. Not productivity. Nope, not productivity. Period.

You got to bear with me for such a long explanation for one-line question. The reason is to help you and others who do not come from Process compliance understand the picture better.
Hope this helps you.


How can I adapt my pedals to account for a difference in leg length?

Question: I have a leg length difference of as much as 1cm due to a non-biking accident.  Adding padding to my shoe doesn't help. A friend recommended that I get pedal stacks (and a longer bolt) to my SPD-style pedals (or any other clipless pedal) for my shorter leg. I know it will affect the rotation, but it's better than wobbling on my bike with uneven hips because of the 1cm difference. Any advice? And where can I buy a pedal stack or any other equipment, so that my leg muscles are as even as possible?
Comment: I thought of posting a comment of a shorter crank on one side, but it doesn't seem like a good idea because it would be lower at the top (instead of higher, like it should be) and would lopside the pedaling effort. I would add to the shoe to stay more 'even' - but the key would really be what makes you most comfortable.
Comment: (The other option is a shorter crank on that side.)
Comment: Are you talking about adding the "stack" to the pedal, or to your shoe?  I would think adding it to the shoe would make the most sense, and one could use a piece of Lexan or such for this duty, after a little work with saw, drill, and rasp.  (I don't know how you could add the height to a standard SPD pedal.)
Comment: I think I might try Daniel's second comment. The "standard" road crank is 172.5mm, but you can get down to 165 and up to 175 which makes for a 10mm = 1cm difference. I *think* that what you would actually need is a 5mm difference as you get 5mm up and 5mm down as the pedals rotate giving you the 1cm. Regardless, I'd involve a good bike fitter.
Comment: @DanielRHicks The gospel according to Sheldon (http://sheldonbrown.com/cranks.html) does not recommend mixing crank lengths. I think Ehyrk has a good point.
Answer: Be very careful about making leg length adjustments on your bike. There are several red flags about this. All of which you may be aware of or may not. 1st, a leg length difference is very difficult to diagnose, ecept with an experienced physio, or an X-Ray/MRI.
Most good physios will send you for an X-ray if they suspect a leg length difference is causing you an issue. 2nd, The body will naturally compensate for up to a 2cm leg length difference with pelvic tilt, and while that is less helpful on the bike, you don't automatically need to add stack height if you have a leg length difference.
And last, a 1cm difference in length does not mean a 1cm compensation, even if you do need to compensate. It is something that needs to be looked at professionally, and any compensation needs to be worked in slowly. Generally, adjustments in the 2mm range in one go are considered appropriate. More than that can(not always, but quite often) cause bigger issues than they solve.
Long story short, be careful what you do, go see a professional medical bike fitter, preferably a physio with extensive bike fitting experience, and follow their instructions. Oh, and be prepared to pay for the privilege, while realizing that it will take time to sort you out properly. There is no magic bullet fix here.
Look up the Boulder Center for Sports Medicine. They specialize in issues of exactly this type, and they designed most of the equipment to diagnose and correct them. Like the 3D bike fitting camera systems.
Comment: Thanks everyone. The length was definitely professionally diagnosed, but as you say, I had never thought of pelvic tilt, which is involved in my case.  I'll seek some professional fitter's advice.  Thanks very much!
Comment: No problem. I don't want to discourage you, but it's easy to damage when you correct an issue like the one you have if you get it even a little wrong.
Comment: @Stephanie - If you're happy with this answer (which seems very helpful), I suggest clicking the Check Mark/Tick on the left to accept it and give the author recognition.
Answer: I have a noticeable difference in leg length and a session with a bike set up professional, resolved the issue on my road bike by switching to Speedplay pedals and using their cleats and shims.  It is not just a question of making the stack height correct but also the fore/aft position of the cleat on the shoe. Using different cranks lengths is not the correct solution.  Although a professional bike set up session is not cheap, it does ensure that all factors (eg, saddle height, arm reach, leg angle at maximum extension etc) are measured and adjusted to give you your optimum riding position.  Well worth the cost to minimize the risk of long term injury.
Comment: How did it go with adding shims under the cleats?  How many did you use?


compute integral $\int_0^{2\pi} \frac{1}{z-\cos(\phi)} d\phi$

Question: Can anybody help me to compute the integral
$$\int_0^{2\pi} \frac{1}{z-\cos(\phi)} d\phi$$
where $z \in \mathbb{C}$ denotes a complex number? Thank you!!
Answer: I suppose that $z \notin [-1,1]$.
$$
I = \int_0^{2 \pi} \frac{d \theta}{z - \cos \theta} =
\int_0^{2 \pi} \frac{ 2 e^{i \theta} d \theta}{2z e^{i \theta} - (e^{i \theta})^2 - 1} =
2i \int_\gamma \frac{d \zeta}{\zeta^2 - 2 z \zeta + 1}
$$
where $\gamma$ is the unitary circle. Since $z \neq \pm 1$, the meromorphic function $f(\zeta) = (\zeta^2 - 2 z \zeta + 1)^{-1}$ has two simple poles
$$
\zeta_{1,2} = z \pm \sqrt{z^2 - 1}.
$$
Now you have to compute the residues of $f$ in $\zeta_{1,2}$, to check when $\zeta_{1,2}$ are contained in the unitary disk, and to use residue theorem to calculate $I$.
Answer: HINT: This is doable by Weierstrass substitution, with an example similar to yours worked out on the linked page.
Comment: I don't think the worked-out example applies to the situation here, $z$ being a complex number.  What to make of the substitution $t = \tan(\phi/z)$?
Comment: The substitution is still $t = \tan(\phi/2)$, and the fact that $z$ is complex is immaterial, as long as $z$ is on on the real interval $[-1,1]$.
Answer: This won't finish the problem off, but it's far too long for a "comment", so I'm putting it here.
Initially it seems heartening that the $z$ just stays put as $\varphi$ goes from $0$ to $2\pi$, but later we may have problems.
So I tried the Weierstrass substitution:
$$
\sin\varphi = \frac{2t}{1+t^2},\qquad \cos\varphi= \frac{1-t^2}{1+t^2},\qquad d\varphi= \frac{2\,dt}{1+t^2}
$$
Then
$$ \int_0^{2\pi} \frac{d\varphi}{z-\cos\varphi} = \int_{-\infty}^\infty \frac{2\,dt}{(z+1)t^2 + (z-1)} $$
If you don't see where the bounds of integration come from then think about how the Weierstrass substitution works.
This becomes
$$
\frac{2}{z-1}\int_{-\infty}^\infty \frac{dt}{\left(\frac{z+1}{z-1}\right) t^2 + 1} = \frac{2}{\sqrt{z^2-1}}\int_{???} \frac{du}{u^2 + 1}
$$
Now we have to worry about the multiple-valued nature of the square-root function and maybe the arctangent function.  The path followed by $u$ through the plane will be an unbounded straight line.
The denominator has zeroes at $\pm i$.  I think one would look at whether the line along which $u$ moves goes between those or they're both on the same side of it.
Maybe I'll add more here later some day.


What type of Paprika

Question: If a recipe calls for "paprika", what type should I use? Does it mean Hungarian, Spanish, California? Also, what type, Hot, Bittersweet, Sweet?
Comment: What recipe?  If we knew what you were making it would be easier to suggest something appropriate.  Defaulting to generic paprika is probably fine, but depending on what the recipe is, and assuming you have a variety of paprikas to choose from, there may be one variety or another that is better suited...
Answer: If the recipe is just asking for "Paprika", they want generic paprika labeled as such. Like this:

According to the McCormick website, this is "sweet" paprika.

The dried, ground pods of Capsicum annuum L., a sweet red pepper.

Similarly, the Spice Islands site calls it sweet

Vividly red in color, paprika is made from ground Capsicum chili peppers. Although, it doesn't pack the punch you'd expect from a chili. Instead, it has a sweet flavor and a delicate aroma that can vary from fruity to sharp.

You certainly do not want "smoked". Both of these companies sell this specifically.
Comment: Note that smoked paprika is really great in situations where you want a bacon flavor (think macaroni or shells and cheese with breadcrumbs and smoked paprika).
Comment: I'm not sure if the mentions of "sweet" there are actually the same sense of the word as sweet paprika - the explicitly labeled sweet paprika I've had seemed sweeter than generic. (It's also usually more flavorful though, so might not be a fair comparison.)
Comment: Theres is not a single paprika labeled pepper in my city, all are named "[insert brabd]'s Sweet/mild/spicy/very hot Pepper Powder / pepper / smoked pepper powder/ smoked pepper". It shouldn't be assumed that the word paprika is used.
Comment: @CptEric If it doesn't use the word paprika, it's probably something else... There's hundreds of varieties of peppers.
Comment: it's paprika. we just happen to been calling it "big pepper" since we discovered it. google pimentón.
Comment: @CptEric who is 'we'? I've never personally seen these terms and I'm specifically talking about American brands and recipes.
Comment: spain, sorry. i thought by now you'd have stalked my profile to find it.
Comment: One more note on the "what does sweet mean?" - I've often heard people divide peppers into hot and sweet. So if it's not hot, it has to be sweet - which means it's pretty easy for "sweet" here to not mean the same thing as for sweet vs bittersweet vs hot paprika.
Answer: In the US, generic paprika is probably closest to bittersweet - not sweet and definitely not hot, just a middle of the road not-too-assertive variety. Recipes aren't likely to be too picky about the exact type, so in the end, you can get away with whatever you personally like.
Answer: When a recipe tells about Paprika, it generally means, "whatever" paprika you want.
There are two usages of paprika, colour, and taste.
If you just want colour, use a sweet one, even a cheap one, it will have no taste but gives a nice colour.
However, if you want a real taste, use real Hungarian paprika, there is a serious difference.
The Hungarian paprika comes in different flavor as well qualities depending on its origin in Hungary.
Here is an excerpt from wikipedia:

Noble sweet (Édesnemes) – slightly pungent (the most commonly exported paprika; bright red)
Special quality (különleges) – the mildest (very sweet with a deep bright red color)
Delicate (csípősmentes csemege) – a mild paprika with a rich flavor (color from light to dark red)
Exquisite delicate (csemegepaprika) – similar to delicate, but more pungent
Pungent exquisite delicate (csípős csemege, pikáns) – an even more pungent version of delicate
Rose (rózsa) – with a strong aroma and mild pungency (pale red in color)
Half-sweet (félédes) – a blend of mild and pungent paprikas; medium pungency
Strong (erős) – the hottest paprika (light brown in color)

The most common are Szeged and Kalocsa.
Do not even try to make Gulyasleves without a true and quality hungarian paprika it won't have any tastes at all.
Oh, and never make burn your paprika by throwing it directly on fire, it will become bitter.
Answer: It depends.
There are six different types. Hot, Hungarian, Plain, Smoked, Spanish, Sweet. The recipe you are following and your intended outcome will drive the decision on which to choose.
Paprika releases its flavor with heat but burns easily. So mix it in with liquid, and make sure it gets hot.
Sprinkled onto a cold dish (like deviled eggs), it remains quite bland. Add it to browned hamburger meat, and you're halfway to taco heaven.
Comment: I don't think the link you give is attempting to specifically classify all paprika as one of only six types - the listing in the first sentence is simply an intro listing various terms one might encounter. Indeed, the article goes on to talk about "Hungarian sweet paprika" and the sweet/hot/smoked varieties of Spanish paprika.

What type of Paprika


Keynote presentation view

Question: Today when I set up my Keynote presentation, the "presenter view" appeared on the audience screen and the audience view appeared on my MacBookPro. The MacBook is a brand new computer and the Keynote is ver. 6.5.2 (2119) I have used this same computer, Keynote and projector for the past 4 months and never had this problem. I tried disconnecting the computer from the projector and restarting Keynote. No difference. I disconnected the computer from the projector and restarted the computer with the projector connected. No difference. I looked in preferences but did not find anything helpful in the display settings. I'm obviously missing something. Has anyone had a similar experience?
Answer: When that occurs, you can move your cursor to the screen with the presenter view (in this case the one that everyone could see); some options will appear, including the ability to swap the displays. This will cause your computer's display to become the presenter display and for the "public" display to just show the slide content.
Answer: connect the projector and goto the "System Preferences"->"Display" to check which display is the primary one. by default the keynote show "presenter view" on the secondary display, and audience screen to the primary display. You can easy to "switch the display" this way

Keynote presentation view


PIQ estimation for FIFO limit order book

Question: Assuming that one doesn't have any kind of priveleged data feed (i.e. info is depth of book and volume executed at bid and ask), is it inherently easier to more accurately estimate position in queue in a limit order book that is strictly FIFO (as opposed to those where orders can receive priority according to any factor other than time of submission)?
Answer: Yes, it's easier to estimate position if there are fewer rules to worry about.


Dimensions and inequalities

Question: How does one go about proving that $\dim(T(X))\geq \dim(T(V)) - \dim(V) +\dim(X)$ where $X$ is a subspace of $V$, a vector space, and $T$ is a linear transformation? Thanks.
Answer: Find a basis for $X$ and extend it to a basis for $V$ using $\dim V-\dim X$ additional vectors. Then $T(V)$ is spanned by $T(X)$ and the images of these additional vectors, and the $\dim V-\dim X$ additional vectors can contribute at most another $\dim V-\dim X$ to the dimension, so
$$\dim T(V)\le \dim T(X) + \dim V -\dim X\;.$$
Answer: Here's an approach through the rank-nullity theorem. Let $T : V \to W$ be the linear map, and let $S : X \to W$ be the restriction of $T$ to the subspace $X$. Then clearly  $\ker(S)$ is a subspace of $\ker(T)$, and hence:
$$
\dim(\ker(S)) \leq \dim(\ker(T)). \tag{1}
$$
Using the rank-nullity theorem, $\dim(\ker(T)) = \dim(V) - \dim(T(V))$, and $\dim(\ker(S)) = \dim(X) - \dim(T(X))$. Plugging these in $(1)$ gives the claim.

Dimensions and inequalities


Is it true that one can not convert to Hinduism from any other religion or vice versa?

Question: One of my friends told me that you are either born as a Hindu or not: You cannot convert from any other religion to Hinduism or the other way round. Is something of that sort mentioned in the Vedas or any other religious text?
Comment: Reason for not allowing people of other religion inside a temple is, those people may hurt our beliefs, practices either with or without their knowledge. Say in Vishnu temples, the step with a gold or brass coat (I am not sure) is still believed to be one of the Aazhvaar. Hindus know this fact and they will not step on it. But other religion people will not know this fact and they will step on it. To avoid these, the governing board (Devasthaanam) of a temple decides these rules, not Vedas!
Comment: Vedas don't talk about other religions at all. There is no initiation ritual or Baptism kind of ritual to 'convert' to Hinduism. If you believe you are a Hindu, believe in Hindu Dharma, then you are one.
Comment: @Mr_Green "while Vedas were being written there was only one religion" - I don't know why people keep saying this, but there is absolutely no reason to believe that this is true. At the very minimum, Egyptian religion long predates the Vedas (though I'll grant the Egyptian peoples and the Vedic peoples probably never met).
Comment: @mjosh, In Guruvayoor temple, ASAIK anyone can fill the `faith form`, which proclaims your faith in the presiding deity and can enter the temple.
Comment: @ViswalingaSuryaS you are right. Even recently in Tirupati some non-hindu religion people entered in to temple with slippers. Height of Irony!!
Comment: I doubt it.. because while Vedas were being written there was only one religion i.e Sanatana Dharma (now known as Hinduism).
Comment: But I am talking about `Pamela Fleig`, a Hindu convert who was denied the entry even though she converted to Hinduism and what about `K J Yesudas` who was denied entry `Guruvayoor Shri Krishna temple` because he is christian by birth though he is Indian. I mean if so many temples are doing this there has to be reason behind.
Comment: @Mr_Green: Yeah, but sometimes they do because of ignorance, but they have real Bakthi. So up to me it will be better if the Devasthanam board conduct special classes or distribute hand-posters to all the people and allow them inside the temple. The sad fact is that even Hindus, does not follow the common practices for a temple.
Comment: Why is the vice-versa part even a question given the number of Hindus that have converted over to Jainism, Buddhism, Christianity, Islam and Sikhism
Comment: So why does temples like `Sri Jagannath` Temple said only `Hindus by birth` should be allowed into the temple. Another such temple is 11th century `Lingaraj Temple`.
Comment: maybe those temples have their own rules formed by a king or some famous person. but I am sure that they are not from Vedas.
Comment: @mjosh this are man made ruled made in preeciding years. Not present in vedas.
Comment: @Mr_Green vedas were **not written** by anyone. They are in existence for many `kalpa` and also many `pralaya`
Comment: Hinduism is decentralized. There is no single supreme authority. If you follow a particular way of life, you are hindu. Since hinduism does npt speak against other's gods and it asks respect other failths, no conversion concept here. period.
Comment: @mjosh: Some ethnic and feudal malpractices which creeped into hinduism during middle dark age and then started parading  themselves in name of religion itself by masquerading. 99% of Hindu temples and practices are free of these malpratices/rules now. But just two three major temples of Orissa,South,Nepal still practise the strict ethinicity malpractise. While these 1% need to be eradicated, but we should see 99% and also conclude that this pratise is not part of hinduis itself, then only we can eradicate it from rest of 1%
Answer: Of course someone can convert to Hinduism. Some of the most famous Bengali Vaishnava masters are ex-muslims. One example is Haridas Thakur a direct disciple of Sri Chaitanya. Another example is the millions of Indonesians who have converted to Hinduism over the centuries. Even in recent times Swami Vivekananda has said the non-Hindus can convert to Hinduism.

"I want to see you Swami", I began, "on this matter of receiving back into Hinduism those who have been perverted from it. Is it your opinion they should be received?
"Certainly", said the Swami (Vivekananda)," they can and aught to be
  taken."
He sat gravely for a moment, thinking, and then resumed, "Besides," he
  said, "we shall otherwise decrease in numbers. When the Mohammedans first came, we are said -- I think on the authority of Ferishta, the oldest Mohammedan historian --- to have been six hundred millions of hindus. Now we are about two hundred millions. And then every man getting out of the Hindu pale is not only a man less, but an enemy the more. Again the vast majority of Hindu perverts to Islam and Christianity are perverts by the sword, or to the descendents of these. It would be obviously unfair to subject these to disabilities of any kind. As to the case of born aliens, did you say? Why, born aliens have been converted in the past by crowds, and the process is still going on. In my own opinion, this statement not only applies to aboriginal tribes, to outlying nations, and to almost all our conquerors before the Mohammedan conquest, but also to all those castes who find a special origin in the Puranas. I hold that they have been aliens thus adopted. Ceremonies of expiation are no doubt suitable in the case of
  willing converts, returning to their Mother church, as it were; but on those who were alienated by conquest-- as in Kashmir and Nepal -- or on strangers wishing to join us, no penance should be imposed."

― Vivekananda (Complete Works V, p233, interview given in "Prabuddha
Bharat", April, 1899)
A princess of Java recently (2017) converted to Hinduism.
http://www.currentriggers.com/world/indonesia-princess-java-became-hindu/
Comment: ref of Haridas Thakur coversion is here : https://en.wikipedia.org/wiki/Haridasa_Thakur
Answer: No, there is no bar in converting from any religion to Hinduism or vice-versa.
Vedas speak about Mlecchas as someone who is not Vedic and not Indian. Basically, mlecchas are people who speak an illegible language and not Sanskrit. The concept of geography, religion and language was all mixed with each other to be indistinguishable.
Hinduism doesn't have a conversion ritual unlike similar ceremony in Christianity  or Islam which causes the inadvertent feeling of disbelief in the believer about his conversion.
Conversion only requires that person to accept the Hindu way of life and leading a Dharmic life.
Ref
1. Mlecchas in Early India
Comment: in other words, Hinduism is a path, not a destination. A Hindu can cease to be a Hindu at any time by disbelieving/disobeying dharma shastras, while a non-Hindu can be a Hindu at any time by believing/obeying dharma shastras.
Answer: The short answer is yes, anyone can become a Hindu.
As others was pointed out, there is nothing in Vedas which prevent people from becoming Hindus(or following Dharma).
A person is a Christian if he/she pledges to follow the Nicene Creed and/or Apostles Creed which lay the definitions of Christian faith. Hinduism does not have such documents of faith which people need to pledge to follow.
What is to to become a Hindu then ? We'd need a clear definition of what is Hindu to say what it is to become a Hindu. Dr.Koenraad Elst debates the definition of Hindu in his book "Who is a Hindu?". He says that people who follow Vedas cannot alone be called Hindus as there are many non-vedic 'Hindu' sects like Lingayats.
In the books Being Different & Indra's Net, Rajiv Malothra traces a commonality between almost all 'Hindu' sects which is the belief in immanence of divinity in every object & every being, belief in the Human nature being originally divine (as opposed to being originally sinful) as the main commonalities and others being belief in Karma & re-incarnation.
Hence if anyone who accepts the above would automatically become a Hindu without any initiation ceremonies.
Answer: Vineet is right and so is Mr_Green. The name says it all. Sanatana Dharama. The word "Dharma" means "way" or "path". It is a way of life and is not a religion. So the question of conversion does not arise. And as Mr_Green said, there was no other religion as such. Anyone can accept the Dharma and continue with his/her life.
Comment: Mr. Srinivasan, I took the liberty to interpret Dharma as "Path of Righteousness" and also "Way of right conduct". And I hope I am not wrong. I just shortened it as Path or Way. I obviously did not take a literal translation or looked up a dictionary. I am sure, by now you must have figured, my Sanskrit is only rudimentary.
Comment: There are many defensible translation of dharma, including "duty", "righteousness", and "religion".  "Way" and "path" are not among them.
Comment: In Sanatana Dharma, "Dharma" doesn't mean "Path of Righteousness". Better translation is "eternal truth".
Answer: 4000+ persons converted to Hinduism . see https://www.hindujagruti.org/news/2100.html
Where you can legally convert to Hinduism?
Goto any Arya samaj temple. After https://www.sacred-texts.com/hin/m12/m12a064.htmconversion, you will be provided legally valid certificate.

http://aryasamajthane.com/conversion.html
http://www.aryasamajmandir.org/affidavit-conversion.htm
https://www.wikihow.com/Convert-to-Hinduism

Many Hindu/Vedic sects will convert you, such as Arya samaj ,Shaiva Siddhanta Church , BAPS, ISCKON etc. Some sects will not convert one. Those sects who will not convert the desiring person, let them choose not to do so, but they can not speak on behalf of all the sects.

If in case you are asking that whether old religious texts mention about conversion .
Argument1) There was no explicit law in vedas or scriptures, as there was no threat. But the basic principle of not a stuck dharma, but a living dharma, which can fight new challenges was already put by Krishna, which can work for Conversion
"Hinduism has been in existence for thousands of years, however it is only after the advent of Christianity and islam that conversion has become a threat to the survival of the religion. During the ancient times there was no such threat, hence the Rishis did not formulate any rule as such for reconversion. However any threat against Sanatana Dharma was met head on. That is why our Gods and Godesses are armed. They have not preached ahimsa of the mahatma variety, instead Lord Krishna terms any refusal to fight against threats to Dharma as cowardice and sin (kshudram Hrudaya dourbalyam). Refer Bhagavad Gita chapter 2, sloka 3, & 31 to 35. Now there is a serious existential threat against our religion and hence we need to put in place the necessary defenses. Making reconversion easy should be one of them."
ref: http://www.haindavakeralam.com/how-to-convert-to-hinduism-a-request-hk4116#comment-158945
Argument 2) you can see lots of people from middle ages converting from other religions to hinduism here.

https://en.wikipedia.org/wiki/List_of_converts_to_Hinduism
https://en.wikipedia.org/wiki/Category:Converts_to_Hinduism

This is going from centuries. Even before the most orthodox middle ages. Esp, Mihirkula like Huna emperor (Mihirakula ruled his empire from 502 to 530CE ), who destroyed buddhist, hindu sites,killed monks. Later converted from his barbaric native religion to Hinduism.
So obviously during 500 CE also, we have documented cases of conversion. So, obviously conversion was allowed. Only thing is that during dark middle ages, when all the world became too much rigid, then our caste system and conversion also changed to inflexible. And Many people still carry the same impression on conversion which was during dark middle ages, in between. But our ancient india was not so inflexible. When new invadors came and tried to assimilate later here in the culture, they were welcomed then. Though nobody tried to evangelize actively to others, like buddhists.
Argument 3A) SCRIPTURE: There is a scripture named Devalasmriti, which allows you to reconvert back the person to Vedic dharma (like if he was converted forcibly by mlechhas/foreigners to their religion, then he could be converted back through this procedure).

Devalasmriti (in sanskrit) http://www.hinduonline.co/vedicreserve/smriti/upasmriti/devala_smriti.pdf and https://archive.org/details/devala_smriti
English language based detailed book on devala smriti

Volume1: https://archive.org/details/DevalaSmritiMukundLaljiWadekarVolume1IntroductionAndText
Volume2: https://archive.org/details/DevalaSmritiMukundLaljiWadekarVolume2CriticalStudy

http://historum.com/asian-history/85165-want-know-more-about-deval-smriti.html
http://hindudharmaforums.com/showthread.php?10850-Who-is-Maharishi-Deval

Example of application of devalasmriti scripture in ancient times:
ref: https://www.gktoday.in/question/during-the-invasion-of-mohammed-bin-kasim-many-hin
During the invasion of Mohammed Bin Kasim in ad 712 many Hindus in Sindh were converted to Islam through questionable means. All of them were reconverted to Hinduism on the authority of ancient text Deval Smriti written by Deval Rishi. Deval smriti writes down rules for it .
Argument 3B) SCRIPTURES: Mahabharat
Answer https://hinduism.stackexchange.com/a/37970/13287 details Indra in Mahabharat's Shanti parva saying about conversion.
Argument 4) What views and actions the important sages have regarding conversion:
( As detailed in https://hinduism.stackexchange.com/a/414 and https://en.wikipedia.org/wiki/Haridasa_Thakur )  Haridas Thakur(born 1450)  direct disciple of Sri Chaitanya Mahaprabhu was a converted ex-muslim.
So CHAITANYA MAHAPRABHU and Swami Vivekananda also converted people from Christianity or islam.
Also ADI SHANKARACHARYA converted people from Buddhism to Vedic Hinduism
(others who supported conversion as part of hinduism : Shastriji_Maharaj(31 January 1865 – 10 May 1951) ( https://en.wikipedia.org/wiki/Shastriji_Maharaj ) , Swami Prabhupada, Dayanand Saraswati, Jnana guru Siva Yogaswami of Jaffna (1872–1964) ( https://en.wikipedia.org/wiki/Yogaswami ),Ramana Maharishi, Sri Aurobindo )
Comment: also related: see https://hinduism.stackexchange.com/a/26326/13287 and see https://hinduism.stackexchange.com/a/26319/13287 and see https://hinduism.stackexchange.com/a/26324/13287 and see https://hinduism.stackexchange.com/a/24722/13287 and see https://hinduism.stackexchange.com/a/24623/13287 and see https://hinduism.stackexchange.com/a/26301/13287
Answer:
One of my friends told me that you are either born as a Hindu or not. You cannot convert from any other religion to Hinduism.

Strictly (scripturally) speaking, your friend is right. P. V. Kane in his 6500-page History of Dharmaśāstra made the same observation:

Hinduism has not been an avowedly proselytizing religion. In theory it could not be so. For about two thousand years the caste system has reigned supreme and no one can in theory be admitted to the Hindu fold who is not born in it.

A Hindu may lose his caste (if he's not careful) and be readmitted into Hinduism (if the prescribed prāyaścittas are followed) but this provision only applies to people who were born Hindu:

A Hindu may lose caste, be excommunicated and driven out of the fold of Hinduism, if he be guilty of very serious lapses and refuses to undergo the prāyaścittas prescribed by the smṛtis.
...
When the sinner performed the prāyaścitta prescribed by the śāstras, he was to be welcomed by his relatives, who took a bath along with him in a holy river or the like and throw therein an unused jar filled with water; they were not to find fault with him and were to completely associate with him in all ways.

In practice though, things worked a bit differently:

The ancient smṛtis do not expressly prescribe any rites for bringing
  into the brahmanic or Hindu fold a person who or whose ancestors did
  not belong to it. But as Hinduism has been extremely tolerant (barring
  a few exceptional instances) it had a wonderful power of quiet and
  unobtrusive absorption. If a person, though of foreign ancestry,
  conformed to Hindu social usages in outward behaviour, in course of
  time his descendants became absorbed into the vast Hindu community.
This process has gone on for at least two thousand years. The
  beginnings of it are found in the Śāntiparva chap. 65 where Indra
  tells the Emperor Māndhātṛ to bring all foreign people like the
  Yavanas under brahmanical influence. The Besnagar column inscription
  shows that the Yona (yavana) Heliodora (Heliodorus) son of Diya (Dion)
  was a bhāgavata (devotee of Vāsudeva)...
In the caves at Nasik, Karle and other places many of the donors are
  said to have been yavanas ... Several inscriptions state that Indian
  kings married Huna princesses, e.g. Allaṭa of the Guhila dynasty
  married a Hūṇa princess named Hariyadevi ... king Yaśaḥkarṇadeva of
  the Kalacuri dynasty is said to have been the son of Karṇadeva and
  Āvalladevī, a Hūṇa princess. These and similar examples show that
  persons of foreign descent and their children were absorbed into the
  Hindu community from time to time. This absorption is illustrated in
  modern times by the case of Fanindra Deb v. Rajeshwar ... in which it
  was found that a family in Kooch Behar not originally Hindu had
  adopted certain Hindu usages and it was held that it had not taken
  over the practice of adoption. How Hindu customs and incidents persist
  even after conversion to Islam is strikingly shown by the Khojas and
  Kutchi Memons of the Bombay Presidency, who though made converts to
  Islam several centuries ago, were held by the courts in India to have
  retained the ancient Hindu Law of succession and inheritance.


Tips for A/B testing?

Question: There seems to an increasing number of A/B testing services (such as Google Website Optimiser) and people using them. Have you got any tips on using and analysing the results from them?
Answer: Philip
Re: Analysing the results. Take a look at the Easy statistics for AdWords A/B testing, and hamsters from Jason Cohen.
It's one of the best articles i've ever read about understanding the statistical relevance of the results of an A/B test. Plus (and this is a big plus for me) it's fun to read.
The main message:
The way you determine whether an A/B test shows a statistically significant difference is:

Define N as "the number of trials." -
  (Click results for variant A + Variant
  B)
Define D as "half the difference
  between the 'winner' and the 'loser'."
The test result is statistically
  significant if D2 is bigger than N.

A full explanation is provided in the article.
All the best,
Matt
Answer: There's a really nice article by Cennydd Bowles that you'll probably find useful Statistical significance & other A/B test pitfalls
Answer: I've been involved with Website Optimizer and Omniture, Marketo as well as some home-grown A/B testing tools.  My key finding is this:  Garbage In - Garbage Out.
The key question is "What are you testing?  WHo is deciding that?"  Is it just "Let's try and beat the control" or is it "Lets learn about our audience."  The latter is much more important.  You have to get to the WHY questions, not just the WHICH.
At Intuit, as example, they tested all kinds of terrible designs by committee and never really moved the needle.  They also never learned why one thing was better than another.
User Experience has to be about getting inside people's heads.  It can't just be randomly throwing pixels together and hoping it is better than the last effort.
Sorry, maybe I flew off-topic.  I have seen AB testing go awry in many ways.  And don't get me started on multivariate testing (DOE).
Last thought:  Avinash Kaushik's blog and books are awesome to learn about analytics. He is a superstar in the field.
Comment: Excellent point Glen - Tools are only as good as the people who use them!
Answer: You might find Smashing Magazine's The Ultimate Guide To A/B Testing a useful A/B testing resource:
It includes a section on Tools For A/B Testing, as well as covering the following:

What Is A/B Testing?
What To Test?
Create Your First A/B Test
Do's And Don'ts
Classic A/B Testing Case Studies
Resources For Deep-Diving Into A/B Testing
Comment: Smashing's article does appear to be very well researched and educational +1
Answer: There is a pretty good article by Jon Von Tividar at
http://www.futurenowinc.com/resources/abtesting.pdf
A good bit about avoidance of false maxima - I am with glen  and think you can only possibly reach the peaks by applying a whole host of techniques first - then tweak using A/B or Multivariate testing. In web design at least you do need an 'intelligent creator' and cannot leave it up to evolution by a/b testing natural selection.
[NB: I am also amazed how often I see people claim results with abslolutely no understanding of even basic stats and significance - and don't get me started on marketing people doing creative concept testing...]
Jon

Tips for A/B testing?


Why do ResNets avoid the vanishing gradient problem?

Question: I read that, if we use the sigmoid or hyperbolic tangent activation functions in deep neural networks, we can have some problems with the vanishing of the gradient, and this is visible by the shapes of the derivative of these functions. ReLU solves this problem thanks to its derivative, even if there may be some dead units. ResNet uses ReLU as activation function, but looking online what I understood is that ResNet solves the vanishing of the gradient thanks to its identity map, and I do not totally agree with that. So what's the purpose of the identity connections in ResNet? Are they used for solving the vanishing of the gradient? And ReLU really solves the vanishing of the gradient in deep neural networks?
Answer: Before proceeding, it's important to note that ResNets, as pointed out here, were not introduced to specifically solve the VGP, but to improve learning in general. In fact, the authors of ResNet, in the original paper, noticed that neural networks without residual connections don't learn as well as ResNets, although they are using batch normalization, which, in theory, ensures that gradients should not vanish (section 4.1). So, in this answer, I'm just giving a potential explanation of why ResNets may also mitigate (or prevent to some extent) the VGP, but the cited research papers below also confirm that ResNets prevent the VGP. Given that I didn't fully read all the papers mentioned in this answer, the information in this answer may not be fully accurate.
The skip connections allow information to skip layers, so, in the forward pass, information from layer $l$ can directly be fed into layer $l+t$ (i.e. the activations of layer $l$ are added to the activations of layer $l+t$), for $t \geq 2$, and, during the forward pass, the gradients can also flow unchanged from layer $l+t$ to layer $l$.
How exactly could this prevent the vanishing gradient problem (VGP)? The VGP occurs when the elements of the gradient (the partial derivatives with respect to the parameters of the NN) become exponentially small, so that the update of the parameters with the gradient becomes almost insignificant (i.e. if you add a very small number $0 < \epsilon \ll 1$ to another number $d$, $d+\epsilon$ is almost the same as $d$) and, consequently, the NN learns very slowly or not at all (considering also numerical errors). Given that these partial derivatives are computed with the chain rule, this can easily occur, because you keep on multiplying small (finite-precision) numbers (please, have a look at how the chain rule works, if you're not familiar with it). For example, $\frac{1}{5}\frac{1}{5} = \frac{1}{25}$ and then $\frac{1}{5}\frac{1}{25} = \frac{1}{125}$, and so on. The deeper the NN, the more likely the VGP can occur. This should be quite intuitive if you are familiar with the chain rule and the back-propagation algorithm (i.e. the chain rule). By allowing information to skip layers, layer $l+t$ receives information from both layer $l+t-1$ and layer $l$ (unchanged, i.e. you do not perform multiplications). For example, to compute the activation of layer $l+t-1$, you perform the usual linear combination followed by the application of the non-linear activation function (e.g. ReLU). In this linear combination, you perform multiplications between numbers that could already be quite small, so the results of these multiplications are even smaller numbers. If you use saturating activation functions (e.g. tanh), this problem can even be aggravated. If the activation of layer $l+t$ are even smaller than the activations of layer $l+t-1$, the addition of the information from layer $l$ will make these activations bigger, thus, to some extent, they will prevent these activations from becoming exponentially small. A similar thing can be said for the back-propagation of the gradient.
Therefore, skip connections can mitigate the VGP, and so they can be used to train deeper NNs.
These explanations are roughly consistent with the findings reported in the paper Residual Networks Behave Like Ensembles of Relatively Shallow Networks, which states

Our results reveal one of the key characteristics that seem to enable the training of very deep networks: Residual networks avoid the vanishing gradient problem by introducing short paths which can carry gradient throughout the extent of very deep networks.

In the paper Norm-Preservation: Why Residual Networks Can Become Extremely Deep?, the authors also discuss another desirable effect of skip connections.

We show theoretically and empirically that each residual block in ResNets is increasingly norm-preserving, as the network becomes deeper
Comment: Thank you, as I can see, it is not ReLU that do the main job, but the skip connections
Comment: @FraMan I would say that both contribute to mitigating the problem. The ReLU, as opposed to e.g. the sigmoid, does not squash its inputs. It basically only sets negative values to zero and lets everything else (i.e. positive values) go through unchanged. In the case of the sigmoid, the values are squashed to fit into a limited range between 0 and 1, so this will force the activations to be between 0 and 1 (which are the inputs to the next layer, and so on). Of course, this will lead to more multiplications between numbers in the range $[0, 1]$, which, if multiplied, become even smaller.
Comment: I think the word "skip" is missleading.  The layers between l and l+t are also processed as normal with weighting and activations. What happens is that the input is added at the layer l+t and then activation on this is done. So, I do not understand that the gradient in backpropagation skips from layer l+t to t (there are other layers in between where the gradient needs to be evaluated)


Can I leave the basket in the portafilter after pulling the shots?

Question: Because it is quite hard to take the basket out of the portafilter, I tend to leave it there. But this means I can't clean the space between them. Is that OK?
Answer: The space between them is very hot to be cleaned right after preparing the espresso, actually. It is better to wait for a while and then remove the portafilter to clean if you are not planning to prepare a second one right after. See image below from a manual.

The space in between can be cleaned after given number of use. E.g. after every 50 use.
Normally, I tend to use decalcifying agents after per 100-150 use. Then, I also remove the parts and clean thoroughly. Otherwise, I just wipe the space in between with a wet cloth.
Answer: I guess the answer is it all depends on your taste.
The espresso purest would tell you that there are coffee oils that are left on all surfaces of the brew path after the water flows through the grounds and these oils quickly become rancid.  I'm not really sure how much oil is left on the portafilter after a shot is prepared, but needless to say, this oil will be present, and in order for it to not affect the flavor of any subsequent shots, needs to be cleaned.
If you cannot detect a flavor difference in the second shot and like the way it tastes, don't worry about it and enjoy your doppio.  Otherwise do some experimenting to really see if cleaning it gives you a better result that you desire.


Should we have a canonical response for folks intent on blowing themselves up?

Question: Inspired by this question and others I've seen like it.  Do we want to steer clear of advising people who are asking questions about performing experiments that are clearly dangerous beyond their recognition, other than a solid "Do not do this"?
Comment: All right, I added a bullet and warning to the off-topic section of the help center and the tour. I also created the custom off-topic close reason below.
Comment: @called2voyage In parallel -- should we remove the [sugar-rocket] tag?
Comment: The tag does seem to have one non-problematic question: https://space.stackexchange.com/q/21211/58
Answer: Custom off-topic close reason:

Questions about dangerous amateur experiments, such as constructing your own engine or propellants are off-topic. Rockets and their propellants are INHERENTLY DANGEROUS and can pose hazards to not just yourself, but others around you (friends, family, neighbors, etc). It may also be illegal. Please see this meta post for more information.
Comment: I *think* this is the right place to necropost on this.  Would it be worth having--perhaps in the already-linked meta post--some "respected" resources to go to?  I can see that the existing arguments against people using information to blow themselves up might still apply, but I could also see it being good to direct people to e.g. [NAR's list of non-US rocketry organizations](https://www.nar.org/find-a-local-club/national-clubs-outside-the-u-s/) rather than having them leave here and go straight to a Colin Furze video.
Comment: Note: The actual custom off-topic close reason may not be in sync with this community wiki, as edits require the effort of two moderators. Ping a moderator in chat for significant changes. Minor changes will be incorporated at that time.
Answer: I think this is an area that maybe we should decide if we even want on topic at all. Maybe something like:

Questions relating to amateur experiments of extremely dangerous matter, such as home-brew rocket propellant, are off topic

Then, we would have something in the Help Center to point people to and we could immediately close such questions. We could even include a notice in the Help Center saying something like:

DO NOT DO THIS! Extreme risk to your life or health.
Comment: @Jack We do allow questions about rockets that don't go to space, but we are allowed to define the scope here however we want as a community--we are not limited to what does or doesn't fit the title. In this case, I think it would be to our benefit to make such questions off topic, even though they might be in line with other questions that are on topic.
Comment: @Jack Got it. :) I just thought I should be clear about how the topic scope works here for any onlookers.
Comment: It'd be hard to argue the 'Space' part of Space Exploration for amateur rocketry too ;)
Comment: I agree - it's kind of dangerous territory to be condoning homemade explosives. I was just having a sly joke about the likelihood of the rocket getting off the ground :)
Comment: I believe that Chemistry SE may have some policy about questions that may involve danger or even nefarious activity. I remember a question about the stoichiometry of air plus natural gas for example, it quickly received a comment with a reminder and link to something.
Answer: I like it, but in keeping with the other closure reasons on other sites I'd like to propose this

Questions about constructing your own rocket or propellants are off-topic. Rockets and their propellants are INHERENTLY DANGEROUS and can pose hazards to not just yourself, but others around you (friends, family, neighbors, etc). It may also be illegal. Please see this meta post for more information.

I linked back to this question just so it would have one, but I would suggest rolling up a separate Meta for this, elaborating why building your own rocket is dangerous. Once it looks good, tag it faq, and lock it (lest people want to debate it).
The Help Center link really doesn't cut it. We need a page dedicated to just this subject.
Comment: Constructing your own rocket (the entire vehicle) that uses a COTS motor is a widely-adopted hobby.  Building your own rocket motors, on the remaining hand.... (pun intended)
Comment: I like the looks of this, but since we only get three custom close reasons I'd like the reason to be broader than just amateur experiments of constructing homemade rocket engines/propellants. I want to cover any life-threatening amateur experiments. That said, with a change to broaden it in that way, I'd be comfortable with making this the new close reason after the suggested meta faq is created.
Comment: @Machavity All right, you can see the change at the community wiki: https://space.meta.stackexchange.com/a/1028/58. It will be a while before the change is live. I submitted the new close reason, but it requires another moderator's approval.
Comment: @called2voyage I've [created a FAQ Meta question](https://space.meta.stackexchange.com/questions/1031/why-cant-i-ask-questions-about-my-amateur-space-projects-and-development). Feel free to edit as needed. I kept it as broad as possible while still highlighting the dangers involved.
Answer: I disagree with the decision to declare all discussion of home engine development to be off-topic. That decision means we're sending people off into the wilderness instead of informing them.
See this question for example. The decision to close as off-topic means we've lost a chance to inform this person. This person would have been better served with an answer that explains the risks of LOX/RP and a recommendation to take the more traditional part of the rocket hobbyist i.e. going from bottle rockets to solid motors intended for the purpose of flying model rockets.
Comment: I share the way you feel about this but there are problems including providing people the opportunity to *mis*-inform others as well, see [this comment](https://space.meta.stackexchange.com/questions/1026/should-we-have-a-canonical-response-for-folks-intent-on-blowing-themselves-up#comment4259_1039) for why SE isn't the right place to allow anybody on the internet to post bad advice along with the good. Down voting only because of this reason.
Comment: I quite agree, @hobbes, I feel questions are being closed for this reason that don't match either "asking questions about performing experiments that are clearly dangerous beyond their recognition" (from the OP) or "dangerous amateur experiments" (from the close text)
Answer: I think it's important and worthwhile to distinguish merely potentially hazardous amateur questions from people who actually are intent on blowing themselves up.
High power rocketry, experiments with small liquid fueled engines, and the like are all things that highly skilled people can do with a reasonable level of safety. Some of these might be more appropriate for Engineering than Space. People who are smart will do their own research and may ask specific questions that indicate knowledge of the field and the risks they are encountering. Other people, like the linked post, will ask incredibly basic "if you have to ask you don't know" questions or questions about the quickest and easiest way to catch a hypergolic tiger by the tail.
Not answering at all will have the biggest effect of driving people to less-reputable places where they will answer.
I think we should be as liberal as possible with this kind of thing.
Answer: I don't believe that making it offtopic is a good idea.
My arguments:

Also the youtube is full with similar videos. A disclaimer is enough there. And we have a more narrow visitor group.
Legality is heavily dependent on the actual country. It might be legal or not, it is not our business to say it. On this reason, the whole politics SE could be closed, because practically all of its posts are illegal in at least one country of the world.
Typically, making the topic of the site narrower, we expand a gap between (1) What good-standing visitors think this site is about, and (2) what about it really is. The difference causes users leaving us with bad feeling, and these are typically expert users, at least enough expert users to ask about home improvised rocket experiments. And I think we want to improve, expand, both in quality and quantity, to once mature the site. It is our most elemental group interest.
Home-built rocketry is an interesting topic, it is a way to learn about the practical space technology, which is by nature a HQ topic here, attracting visitors and improving the site, both in quality and in quantity.
Citing Benjamin Franklin: He who sacrifices freedom for security deserves neither.
How could we improve the safety of anybody by cutting them off from information? The best way for safety is if you have all the required information.

I think a disclaimer is far more than enough in this case, or at least a FAQ entry with a warning, but not a close reason.
Comment: 1) You can get model rocket motors that are single-use engines with the propellant included when you're making homemade rockets. You do not have to make your own engine or propellant. 2) You can buy them online (this varies with locality), and it improves safety because they are built to be reliable. 3) There is more to rockets than just the propulsion: shape, staging, fins, number of engines, etc. 4) Refusing to share information on homemade engines or propellant does not improve safety for those who do, but it does communicate that we disapprove. Professional development is safer.
Comment: @peterh nobody is *cutting anybody off* from information. But SE is not a good platform for this because there is no control over how wacky, litigious users (or those they injure) may get or how bad advice in answers or comments can get. We can flag stuff but once it's been read it can't be *unread*. Try to ask how to make explosive mixtures in Chemistry and see how quickly you get shut down. Like several other kinds of question, this kind is not a good fit for Stack Exchange.
Comment: We do allow questions on home-built rocketry, just not home-built engines/motors or homemade propellant.
Comment: @called2voyage If you want to become once a mod of the *matured* SpaceSE, I strongly suggest to avoid this topic-narrowing, overmoderating direction with all the influence you have.
Comment: 5) The formulation is intentionally broad to allow us to be judicious and not get into rules lawyering. It is not intended to allow closure of any question one thinks is dangerous. If you disagree with the closure of any question under this reason, you can take it to meta--just like anything else that is closed. We have already closed questions for being dangerous before without this reason, the custom reason just makes things more clear which is good.
Comment: @called2voyage I am not sure, (1) how could a home-built rocket work without a drive or propellant, (2) where could I buy rocket drives on the ebay, how does it improve safety, (3) how could we call a rocket "home-built" if neither its drive and propellant is home-built, (4) how could improve the safety of anybody by cutting them off from the information from anything, and (5) the notice is about *"amateur experiment of extreme danger"*, which is a very broad formulation with the deadly potential to get the site to self-mutilate itself by overmoderation.
Comment: In response to your last statement, the decisions here are made by the community. The community has been firmly against these types of questions for some time, which is why I made the proposal that I did on this question. I am not overmodding because I am not stepping beyond what the community desires, just helping communicate it.
Comment: If you want to know how the community decides such things: votes. For example, the votes in this meta discussion. You can see what was upvoted and what was downvoted. For the record, I didn't downvote your post.
Comment: Personally I don't think we should be "cut off" from parade questions [1](https://space.stackexchange.com/q/30356/12102), [2](https://space.meta.stackexchange.com/q/1049/12102) but the voters have spoken :-(
Comment: @uhoh On some mysterious reason, as sites are growing, *always* a psychotic "core team" appears, whose first task is to make the site terrible for the possible largest group of visitors. Yes, they have always their "reasons". I don't know, what could be done with it. I think, the SE should intervene and eliminate them, but they are mainly ignoring this problem, and their public communication even supports them. Well... somewhere I've heard, "fish is stinking from its head". That means, yes, structural problems of a system are the fault of its top-level controlling body.


What do the three dots on the network icon mean?

Question: Trying to diagnose my sudden lack of wifi, but I have no idea what this icon means.
Comment: Could you upload a screenshot, please?
Comment: Possible duplicate of [Wifi problems after restart or suspend](http://elementaryos.stackexchange.com/questions/1382/wifi-problems-after-restart-or-suspend)
Comment: Unfortunately, I can't recreate the problem as it seems to be resolved. FWIW, though, it was basically the same icon that appears with airplane mode enabled (three terminals grayed out), except it's three white dots like an ellipsis in the middle instead of a white X in the bottom right corner.
Answer: If you had wifi and then suddenly it disappeared then you should first try switching off and on wifi and if doesn't work then just restart network manager with sudo service network-manager restart.
If you still have no internet then just restart your computer.
I have the same problem sometimes. I couldn't find out better solution.
:)
Comment: If it happens again I'll give it a go, but it only happened while I was trying to get [this fix](http://elementaryos.stackexchange.com/q/9806/7863) working and messed up at some point along the way. And I'm not TOO interested in trying to recreate it ;P
Comment: Well, It is jest restart Of your wifi, so you can use it whenever you have problem with internet. From my experience it happens sometimes even when you don't play with wifi. So if something's is wrong, now you know how to restart it without rebooting computer . :)
Answer: There are various forms of this:
Wifi problems after restart or suspend
Wifi down after waking up from a long suspend
WIFI sometimes not working
Losing wifi connection is a Ubuntu 16.04 wifi issue: 16.04 LTS wifi connection issues.
The change of icon is related to that too - but the form of the icon may vary depending on the icon-set.
It became a rare occurrence for me after I did this: https://askubuntu.com/a/768268/47206
When it still happens I do  service network-manager restart (asks for password anyway). That command can be run from a shortcut or added into a ~/.local/share/applications/restart-wifi.desktop file and run from slingshot.


Why don't Chandler & Rachel recognise each other in "The One With The Flashback"?

Question: I find this event in the Friends episode "The One With The Flashback" even more intriguing than another question I had posted some time ago. In later seasons, it is well established that Chandler & Rachel know each other from college as well as thanksgiving dinners at the Gellers'. How then did they not recognise each other when Chandler dropped the ball?
Answer: The usual explanation is that Rachel and Chandler simply didn't recognize each other.
However:

it is highly unlikely that Rachel wouldn't remember a guy that was the reason of Monica loosing weight, that she was in ER with after he lost a tip of his toe and that she was kissing on a college party
more importantly, in the first episode Monica introduces Chandler to Rachel - if the two had met each other several times before Monica would surely remember this:

This is everybody, this is Chandler, and Phoebe, and Joey, and- you
  remember my brother Ross?

This means that initially Rachel and Chandler simply didn't know each other before her moving in with Monica and their past was retconned in Season 5, most probably to add some interesting events to Monica and Chandler's history. The bottom line is that this is just another Friends plot hole, albeit one of the biggest.
Comment: My personal favourite plot hole(not mentioned in that link) is when Monica mentions in season 1 that she's allergic to cats... and then fails to care when Phoebe starts carrying around a random cat she thinks is her reincarnated mother for like 6 episodes later on.
Comment: @Steve-O: Allergies come in many forms. A family member of mine is allergic to dogs, but has little to no reaction unless they physically touch the  dog. Was Monica''s cat allergy ever elaborated on, e.g. mentioning that she's highly allergic?
Comment: "it is highly unlikely that Rachel wouldn't remember a guy that was the reason of Monica losing weight" — given Rachel's somewhat self-absorbed nature in her younger days, she probably didn't remember anything about Chandler aside his flock of seagulls haircut.
Answer: Chandler did know Rachel well before they actually became good friends. of-course she was the friend of Chandler's best friend (Ross) Sister. Having said that, Chandler probably took Rachel as just another friend of fat Monica. did not pay much attention nor did care much about Rachel Specifically, more because he had probably never thought he will end up living across the hall from her and  share good friendsship
Comment: I think both did not gave much attention for each other, but Chandler knew Rachel mostly because of Ross' crush on her. so he didn't give her much attention and possible he had very little memory of her after all those years until she elope from her wedding
Answer: Only thing happened between them was that chandler used his sarcastic instincts and rachel being posh rich girl, just ignored him. she even didn't give much attention to monica. she just showed her engagement ring to her and gave only one look at chandler. so to chandler, rachel was another girl he failed at flirt and to rachel, he was just another guy she sees at a bar
Answer: I think rachel didn't recognize chandler because whenever they met at Thanksgiving and college chandler have a very different hairstyle.....and the reason rachel didn't recognized by chandler because her nose is not done then
Comment: Hairstyle couldn't be the reason. Strongest characteristics being for chandler was his sarcasm. and in that episode Rachel never paid any attention to Chandler, neither did he.

Rachel's nose was big, yeah I agree. but could you be more wrong if you cant identify a person just because the nose?

Why don't Chandler & Rachel recognise each other in “The One With The Flashback”?


In functional programming, does having most of the data structures immutable require more memory usage?

Question: In functional programming since almost all data structure are immutable, when the state has to change a new structure is created. Does this mean a lot more memory usage? I know the object oriented programming paradigm well, now I'm trying to learn about the functional programming paradigm. The concept of everything being immutable confuses me. It would seem like the a program using immutable structures would require much more memory than a program with mutable structures. Am I even looking at this in the right way?
Comment: It _can_ mean that, but most immutable data structures reuse the underlying data for the changes. Eric Lippert has a great blog series about [immutability in C#](http://blogs.msdn.com/b/ericlippert/archive/2007/11/13/immutability-in-c-part-one-kinds-of-immutability.aspx)
Comment: I would take a look at Purely Functional Data Structures, It's a great book that is written by the same guy who wrote most of Haskell's container library (though the book is primarily SML)
Comment: This answer, related to running _time_ instead of memory consumption, may also be interesting for you: http://stackoverflow.com/questions/1990464/efficiency-of-purely-functional-programming
Comment: You might find this interesting: http://en.wikipedia.org/wiki/Static_single_assignment_form
Answer: The only correct answer to this is "sometimes". There are a lot of tricks that functional languages can use to avoid wasting memory. Immutability makes it easier to share data between functions, and even between data structures, since the compiler can guarantee that the data won't be modified. Functional languages tend to encourage the use of data structures that can be used efficiently as immutable structures (for instance, trees instead of hash tables). If you add laziness into the mix, like many functional languages do, that adds new ways to save memory (it also adds new ways of wasting memory, but I'm not going to go into that).
Answer:
In functional programming since almost all data structure are immutable, when the state has to change a new structure is created. Does this mean a lot more memory usage?

That depends on the data structure, the exact changes you performed and, in some cases, the optimizer. As one example let's consider prepending to a list:
list2 = prepend(42, list1) // list2 is now a list that contains 42 followed
                           // by the elements of list1. list1 is unchanged

Here the additional memory requirement is constant - so is the runtime cost of calling prepend. Why? Because prepend simply creates a new cell which has 42 as its head and list1 as its tail. It does not have to copy or otherwise iterate over list2 to achieve this. That is, except for the memory required to store 42, list2 reuses the same memory that is used by list1. Since both lists are immutable, this sharing is perfectly safe.
Similarly, when working with balanced tree structures, most operations require only a logarithmic amount of additional space because everything, but one path of the tree may be shared.
For arrays the situation is a bit different. That's why, in many FP languages, arrays are not that commonly used. However, if you do something like arr2 = map(f, arr1) and arr1 is never used again after this line, a smart optimizer can actually create code that mutates arr1 instead of creating a new array (without affecting the behavior of the program). In that case the performance will be as in an imperative language of course.
Comment: Out of interest, which implementation of which languages do reuse space as you described near the end?
Comment: @delnan At my university there was a research language called Qube, which did that. I don't know whether there's any used-in-the-wild language that does this, though. However Haskell's fusion can achieve the same effect in many cases.
Answer: Naive implementations would indeed expose this problem - when you create a new data structure instead of updating an existing one in-place, you have to have some overhead.
Different languages have different ways of dealing with this, and there are a few tricks most of them use.
One strategy is garbage collection. The moment the new structure has been created, or shortly after, references to the old structure go out of scope, and the garbage collector will pick it up instantly or soon enough, depending on the GC algorithm. This means that while there is still an overhead, it is only temporary, and won't grow linearly with the amount of data.
Another one is picking different kinds of data structures. Where arrays are the go-to list data structure in imperative languages (usually wrapped in some sort of dynamic-reallocation container such as std::vector in C++), functional languages often prefer linked lists. With a linked list, a prepend operation ('cons') can reuse the existing list as the new list's tail, so all that really gets allocated is the new list head. Similar strategies exist for other types of data structures - sets, trees, you name it.
And then there's lazy evaluation, à la Haskell. The idea is that data structures you create aren't fully created immediately; instead, they are stored as "thunks" (you can think of these as recipes for constructing the value when it's needed). Only when the value is needed does the thunk get expanded into an actual value. This means that memory allocation can be deferred until evaluation is necessary, and at that point, several thunks can be combined in one memory allocation.
Comment: Wow, one small answer and so much info/insight. Thank you :)
Answer: I only know a little about Clojure and it's Immutable Data Structures.

Clojure provides a set of immutable lists, vectors, sets and maps.
  Since they can't be changed, 'adding' or 'removing' something from an
  immutable collection means creating a new collection just like the old
  one but with the needed change. Persistence is a term used to describe
  the property wherein the old version of the collection is still
  available after the 'change', and that the collection maintains its
  performance guarantees for most operations. Specifically, this means
  that the new version can't be created using a full copy, since that
  would require linear time. Inevitably, persistent collections are
  implemented using linked data structures, so that the new versions can
  share structure with the prior version.

Graphically, we can represent something like this:
(def my-list '(1 2 3))

    +---+      +---+      +---+
    | 1 | ---> | 2 | ---> | 3 |
    +---+      +---+      +---+

(def new-list (conj my-list 0))

              +-----------------------------+
    +---+     | +---+      +---+      +---+ |
    | 0 | --->| | 1 | ---> | 2 | ---> | 3 | |
    +---+     | +---+      +---+      +---+ |
              +-----------------------------+

Answer: In addition to what has been said in other answers, I would like to mention the Clean programming language, which supports so-called unique types. I do not know this language but I suppose that unique types support some kind of "destructive update".
In other words, while the semantics of updating a state is that you create a new value from an old one by applying a function, the uniqueness constraint can allow the compiler to reuse data objects internally because it knows that the old value will not be referenced any more in the program after the new value has been produced.
For more details, see e.g. the Clean homepage and this wikipedia article