Any Open Source Games That Can Be Ported to Android?

Question: I'm looking for some other open source games out there that I can port (easily or not) to Android.  I know that it's possible to port Wolfenstein and Doom and was wondering if there are any others out there.  I was thinking of Civilization (I remember a linux port some time back) and a few others.  It can be in C/C++ or Java.  Thanks in advance.
Comment: Whoever did the down vote, care to explain why?  A down vote helps me not.  You telling me I'm a newb and can find X stuff in Y place, does.
Comment: Just because the game code is open source doesn't mean you can release a port with the content.  The content (textures, sounds, levels, etc) is under copyright.  You'd have to look for a game that's completely open source, and those are pretty few and far between.
Comment: @Tetrad I don't think I said I wanted to release the game.  This is for learning purposes only.
Answer: Your best bet is probably cube.  It uses the zlib license.  It's been ported to pretty small platforms so running on an android device isn't out of the question.
Comment: @Soshimo, you should really wait more than 4 hours before accepting an answer, as it kind of discourages more answers because anyone else posting **knows** that their answer will not be accepted.
Comment: @AttackingHobo Posting just to get an answer accepted kind of defeats the purpose of the site doesn't it?  Getting points seems kind of secondary to actually having people help others.  Maybe the point system is flawed if that's the only incentive to post.  I have a feeling that a lot of people don't share your sentiment.  Looking over your past comments it seems you have a definite agenda with accepting answers early since you seem to comment whenever you get a chance.  If I didn't know any better I would say it's a bot.
Comment: Not meaning to butt-in here, but I agree with AttackingHobo on this point. 'Accepting' an answer is basically equivalent to saying 'I'm happy with this answer, I don't need any more' which is why questions giving a list rarely have accepted answers. EDIT: Ninja'd by Tetrad.
Comment: @AttackingHobo (and the rest) If that's the case then the developers of this website should turn off the auto notification that you have unanswered questions.  This being my first time here I just followed the suggestions of the notification.  Thanks for all the input though - tough crowd around here.
Comment: Sweet, Cube looks great.  I have something to play with now and maybe get some oohs and ahs.  I have to justify my late nights and evenings to the wife. ;)  I can't upvote but I'll accept this as answer.  Thanks!
Comment: This conversation shouldn't be a part of this comment thread.  If you really want to discuss the merits of accepting answers, take it to meta.


SharePoint Migration from 2010 to 2016

Question: To migrate SharePoint from 2010 to 2016, since there is no direct approach for migration apart from moving it to 2013 first and then migrating it to 2016. Will Microsoft provide a temporary 2013 license for migration or do we need to buy 2013 license as well?
Answer: I disagree with Anand's recommendation.
From your question, it sounds like you're ok with and planning too use the database attach upgrade method. If that is the case, I recommends that you simply download the fully functional 180 day trial from Microsoft here:
https://www.microsoft.com/en-us/evalcenter/evaluate-sharepoint-server-2013
It's a VM img file format. This will give you 4 months to complete the double hop upgrade.
Comment: Yea, this sounds better.  I used the migration tool as I found it easier than creating the complete environment again and migrate the item twice.
Comment: With the img file you simply attach it to a VM. It's already pre installed and configured. That's the beauty of Microsoft's trial images. ;-)
Answer: The best way of migration is to use any Migration Tool. I would recommend, Saketa Migrator as it consists of many features and as per the client requirement, they will customise the price and the product.
All you have to do is register for a trial version which would be of 7 days(which I guess is quite enough if you know how to manage :P) and download the app. Just paste you source and destination and click the play button. Its quite easy.
You can do the same with the other migration tools too and would be cheaper than buying the SP2013 license.

SharePoint Migration from 2010 to 2016


Can I make bread/pizza dough with only cricket flour and no wheat flour

Question: I want to make bread and pizza dough, but all recipes I find online include other types of flours than the one I am interested in. Is it possible to make with only cricket flour? Acceptable ingredients are cricket flour, eggs, yeast, water, salt and baking powder.
Comment: From https://en.wikipedia.org/wiki/Cricket_flour: Cricket flour is **an erroneous term** used to refer to powder made from crickets using various processes. **Cricket flour differs from true flours** made from grains by being composed mainly of protein rather than starches and dietary fibre. (emphasis mine)
Comment: When even the producers of cricket flour only offer recipes including more wheat than cricket, I think you are probably on a hiding to nothing.
Comment: Probably someone looking for low–gluten flour
Comment: Furthermore — and pardon the frivolous comment, — If you really want to up the ante, you could consider using insect eggs.  Grasshopper eggs are especially tasty.
Comment: Soon as I get enough chitin and a weak base which can gummify the chitin while not rendering it inedible, I'll let you know how things go in an answer.
Answer: I think you will be disappointed.
While a fantastic protein source, cricket flour does not contain the gluten proteins that make bread what it is. Therefore, bread made with cricket flour must get its structure somewhere else. The majority of recipes I can find are quickbreads which get their structure from added eggs blown up with baking soda. Dense and tender, not light and chewy.
Some recipes for things like cookie dough or standard bread use cricket flour as a protein enhancer but not a complete substitute for wheat flour.
If you are determined to make bread dough without wheat gluten then you will have to employ tricks from standard gluten-free recipes. Making your "bread" more like a cracker or adding gums of various types. Keep in mind that no gluten-free bread will come close to real bread and especially high protein pizza dough. They just can't get the light, crispy, chewy texture.
Comment: I'm guessing that cricket flour originally came about when someone's flour got infested and they passed it off as "I did that on purpose!" :D
Comment: Agreed. The original poster might want to look at "banting" recipes for "bread" - which is mostly ground seeds/nuts + some psyllium fibre bound together with (a lot of) egg+milk and lightened up with baking powder. Not bad, may take the place of bread/muffins, but not completely indistinguishable from bread either. Pizza base - not sure. I've seen some recipe using cauliflower meal for a base, never tried, never tasted, probably not translatable to crickflour.
Answer: I am presuming you mean cricket POWDER not cricket FLOUR in your question.
There can be some confusion as a lot of companies sell their cricket powder as cricket flour but as it is 100% milled crickets it isn't a flour and shouldn't be labelled as a flour because it leads to this sort of confusion.
There are products on the market that are labelled as cricket flour that are a mixture of flour and cricket powder. If you are using one of these then use it the same way you would use normal flour.
If you have cricket powder then you can still use it but I would advise using it as a replacement of up to 20% of whatever flour you are using in the recipe.
Using 100% cricket powder can be done but its not advisable as cricket powder is expensive and using 100% on a pizza base that won't taste nice doesn't make sense. The base will be grainy in texture and depending on the species used it could have an overpowering earthy flavour that probably put you off using it in the future.
Comment: This is a very good explanation of the differences. Welcome to the site!
Answer: You could make "something" out of it.
It might even be good, but it won't be anything anybody would expect if you said you were making pizza.
Pizza crust is held together with gluten, which is something crickets don't have.
Pizza dough also rises, which is something crickets won't do. At least not when they're dead. 8-)
If you have a bunch of cricket flour, give it a try. It might even be tasty. You'll never know until you try.
Comment: Yeah, I want to try, but cricket flour is expensive and I only have very little, which is why I asked if anyone knew of the correct ratios of ingredients :) I am not expecting it to be like real bread, and see this more of a fun experiment.


Very important peace lily not growing at all

Question: My boyfriend has a peace lily from his 12 year old daughters funeral that was 6 years ago (we have been together a little over a year now) I have cut brown spots off, I need to again. I water 1-2 times a week. It doesn't grow at all. I also just placed it by the door for some light today. Any suggestions would be helpful.  I thought of re potting it but if I kill it , it would really bother me. Hoping I can add pics
Answer: There are several things that could be going on with your Peace Lily.
Over watering can be an issue. As a general rule, you should allow the top 1-2 inches of soil to dry between watering. I also noticed that the plant is in a grower pot that sits inside another pot. Water draining out of the drainage holes in the growers pot will collect in the bottom the outer pot, causing the soil to stay too wet. You can add some rocks (I like to use river rocks) to the bottom of the outer pot to help keep the plant from sitting in water but you should also be careful to empty the water from the outer pot about 30 minutes after watering.
Peace lilies can be sensitive to chlorine and fluoride that is found in tap water. I recommend using distilled water. That is the best way to solve water quality problems such as chlorine and fluoride, which many plants are sensitive to. These chemicals in the water causes the brown leaf tips.
Peace Lilies need bright, indirect light, but no direct sunlight. The plant needs lots of light to flower.
I noticed that a few of the leaves look like they have been chewed on. Do you have a dog or a cat in the house? Peace Lily is considered a poisonous plant.
There are almost no 'safe' plants. Any plant can cause harm to children and animals if chewed or ingested. No matter if it is considered poisonous or not. Even 'safe' nonpoisonous plants can cause stomach upset, skin rash, lip/tongue swelling or could cause a potentially fatal allergic reaction. Especially in young children, puppies and/or kittens.
It is always best to keep all houseplants in a place out of reach of children and pets.
I am very sorry for your boyfriend's loss. Hopefully this will help keep the Peace Lily a healthy, flowering memento.
Answer: They always say peace lillies need bright indirect light, which is most of my house, but ive always had the best luck having them grow in a low light, sometimes I feel like thats wrong because literally everyone says bright indirect light. So I put it in that light setting a few days and the tips start turning brown. I have an app on my phone called Plantera that helps keep track of water and other info. It has be water based on the pot, type of plant and lighting. For my peace lily it has me keeping the soil staying moist, but not soaked. The app also gives advice on when to fertilize and how often to repot, type of soil etc. I used to not think this was an important thing, as well as repotting with new soil, but I have seen so much growth this summer on 30+ plant types by doing this. Pruning damaged or dying leaves when they are ready will also allow the plant to give energy into growing new leaves.


How do I calculate pointing and stability requirements for a platform (Cubesat, UAV) if we know sensor details (IFOV, Integration Time etc)?

Question: My project involves developing a multi-mission modular satellite bus. I have couple of payloads under consideration and have the necessary sensor details. Based on that I am trying to figure the pointing and stability requirements of the satellite.
Comment: I'm afraid the subject is way too broad given the scarce details you have given.
Answer: The pointing stability requirement of a platform is dictated by the payload that will use the platform.
What will the payload do? What pointing accuracy and stability does it require to function well and do what it is supposed to do?
Just as one particular example, if it has a camera and will photograph the Earth, then you need to look into the magnification - how many pixels per degree, and the exposure time you'll need. Do you need to spin the satellite in order to slew the field of view in order to track the image of the Earth's surface with its apparent motion of 7 kilometers per second, or do you just need to hold steady?
Start with the purpose of the mission and work backwards to find technical requirements.
If you want to include some more information about the payload's mission and function, that might help attract a more helpful answer.
However: you might have meant to ask about the pointing and stability performance rather than requirement. In that case you should revise the question.
In any event, please leave a comment here if/when you revise the question.
Comment: It's also worth noting that performing a bit worse than is optimal for the payload may still exceed mission requirements, particularly with COTS components.


Cannot (re)install version 4 of .net framework on Windows XP

Question: On Windows XP, SP3, I had 4 auto updates that would run and then immediately get scheduled again because they needed to run.  No errors reported, they just ran over and over.  I tried doing them manually, I tried downloading different versions of them and doing them manually, I disabled my virus software, I uninstalled my virus software, etc., etc.  I worked on it off and on for months and never got a resolution.
I finally read about someone who uninstalled .NET Framework -- all versions -- and then the updates would run.  I uninstalled .NET Framework and the update problem went away (not to say it won't come back).
However, now I can't get .NET Framework v4 to install again, and of course I have an application that requires it (TurboTax, if that makes a difference).  I have downloaded full and network versions of the .NET Framework install, and get the same informative error message:

  Installation Did Not Succeed
.NET Framework 4 has not bee installed because:
Fatal error during installation.
For more information about this problem, see the log file.

The log file is tens of thousands of lines; I did find:

  Returning IDOK, INSTALLMESSAGE_ERROR[There is a problem with this Windows Installer package.  Please refer to the setup log for more information.]
MSI(C:\DOCUME~1\rcook\LOCALS~1\Temp\Microsoft.NET Framework 4 Setup_4.0.30319\netfx_Core_x86.msi) Installation failed.Msi Log:
Microsoft >NET Framework 4 Setup_20121027_154208640-MSI_netfx_Core_x86.msi.txt

So I searched for and found THAT log file and it had something in it about an inability to update a file because it was in use by another process.
So I used msconfig to disable all startup processes -- since I didn't have any applications running, I figured it had to be something automatically started -- and rebooted, and ran it again.  I got the same results, with different log file names, and now I can't find EITHER of the log files.  I searched all directories under my (admin) user id for files ending in msi.txt - nothing.
Is there something I'm missing about installing this?  I got version 2 installed, because evidently you can (or are supposed to) have multiple versions installed at one time.  I got a similar set of errors on 3.5 on a previous attempt.  Do I have to do 3,0 and then 3.5 and then 4.0, or something?  None of the instructions I've been able to find say so, but then none of the instructions I've been able to find are working...
Answer: I'd start by trying to install 3.5 Sp1 first:  http://www.microsoft.com/en-us/download/details.aspx?id=25150, then move on to trying to get 4 installed.  The versions are confusing, but i've gone from 1.1 to 3.5 sp1 without issue.
Comment: ok, tried that: "An error occurred during setup.  Installed files have been removed from your computer.  For known issues and troubleshooting information, see the online Readme.  For error information see Error Log."  The error log has "MSI returned error code 1603"; a site or two ids this as attempting to install to a folder that is encrypted, on a substitute drive, or for which System does not have full permissions.  I don't know what folder it is they're attempting to use.  I also notice the message refs ".NET Framework 2.0a" is not installed; is it trying to install that before 3.5?


LEGO custom One Piece

Question: Does anyone know where I can find custom LEGO figures or MOCs of the One Piece Manga/Anime, preferably made using authentic LEGO elements?
Comment: What is a "Lego custom one piece crew"? Are you talking about a service that makes custom minifigs? In that case - check out [minifigs.me](http://minifigs.me).
Answer: I'm assuming you are referring to the One Piece anime series.
There are no official Lego sets for the One Piece anime series. If there were, you'd have seen them in the Lego catalogs.
Searching the web, I've found that there is a company called Diamond Blocks that has created One Piece sets. Strangely, they don't seem to have minifigs of the crew.
You could perhaps customize your own minifigs. You could make some stickers and apply them to your existing minifigs, for example.
Or you could contact Lego company and ask them. One Piece is a pretty popular series, so assuming this Diamond Blocks company doesn't have an exclusive license, they might just be interested in creating it.
Answer: There are third party companies like KORUIT that have made "One Piece" minifigures. You can check out the review on the KORUIT "One Piece" minifigure here: https://customizeminifiguresintelligence.wordpress.com/2018/12/14/review-of-koruit-one-piece-minifigures-xp036-041-kt1008-kt1013/

LEGO custom One Piece


What does the "keleven" digit look like?

Question: In the Finale episode of The Office, we learn that one reason Kevin was fired, was for using his made-up number "kelevin" to correct accounting errors.  His replacement is seen asking Oscar about this "strange symbol."  Do we have any way of knowing what this symbol looks like?
Comment: @APaleShadow: No, that would make a bad answer. The question could very well be answered authoritatively, if the "kelevin" digit has ever been written, and if the producers or actors from the show ever disclose this information.
Comment: I think that any answer would have to be speculative at best whihc makes this not a good question
Comment: We may well one day be fortunate enough to see what the Keleven looks like, when the original format recording is hopefully released. It all depends on the producers of the show. We have the technology and the storage capacity to make it happen. The original film recording almost definitely includes the Keleven as seen at minute 7 second 14 in the final episode 'Finale' (s09e23) of The Office. [when Dakota is questioning Oscar]
Comment: Kevin was referring to a 'plug' it isn't a symbol. For example if you are trying to reconcile something and you are off by 200. You would just create a plug (keleven) equal to 200 to have the account balance. Think of it as an offset.
Comment: You've apparently never watched that episode, or read the existing answer or even the question. They clearly refer to it as a written symbol.  "Dakota: Hi. I keep seeing this symbol in the accounts from last year. It's..it's all over the place. I don't know what it means."
Answer: So the keleven, as you say, was used by Kevin to balance the books:

Oscar: [on the phone] Years ago, the senator promised a left turn lane
by the Arby's. So I wanna know where in the name of horsey sauce is
it? Well, yeah, you…hold on.
Dakota: Hi. I keep seeing this symbol in
the accounts from last year. It's..it's all over the place. I don't
know what it means.
Oscar: That's the reason Kevin got fired. It's
his magic number. He used to use it to balance his accounts. He used
to call it a Keleven. He told Dwight, [imitating Kevin] "A mistake
plus Keleven gets you home by seven." He was home by 4:45 that day.

Aside from these words and despite extensive googling, there is absolutely no reference anywhere to what the symbol might actually look like. I even went through a combination of different searches on google images and instagram, but came up empty handed.
Therefore, I'm going to say no, we have no way of knowing what the symbol looks like as the producers of the show have never attempted to release it (and have likely never even created it).
Comment: Ditto. I searched extensively as well.


SQL syntax highlighting and code completion in Eclipse PDT

Question: Is there a way of enabling highlighting (and/or code completion for SQL) for SQL syntax in PHP strings variable while developing some PHP works related to SQL using Eclipse PDT?
Answer: No, there is no such option and currently no Eclipse plug-in exists which provides this feature.
However that does not mean such a feature would be impossible to build.


Is it possible to use more than one focus point on the Nikon D3200?

Question: When focussing with the D3200, is it possible to select more than one focus point? If so, how?
Comment: Possible duplicate of [How can I get everything in focus?](http://photo.stackexchange.com/questions/4748/how-can-i-get-everything-in-focus)
Answer: You cannot choose multiple points to have in focus at the same time in a shot.
You can let the camera choose which one of several points it will use as a focus point in the shot, but the camera will not make any attempt to get all the points in focus - just one.
You have limited control over how much of a scene around a selected single focus point will be in focus.  To do this you control Depth Of Field mainly by selecting aperture.
It is not always possible to get everything you want in focus within the constraints imposed by available light or because you must balance between wanting a small depth of field for compositional reasons and needing a large depth of field for focus reasons.  It takes time and practice to learn to find a good balance between these conflicting requirements when shooting.
Comment: Thanks a lot StephenG for the answer for I have been always thinking that it is possible and has asked many a people and they simply told that they don't know. By the way focus stacking is a great technique that I can use for any further need.
Answer: As pointed by StephenG, you cannot always in a single shot focus on multiple different points, especially if they are at significantly different distances from the camera. You can adjust depth of field (with the associated drawbacks to maintain exposure), but this has its limits.
What you can do, however, is take multiple pictures of the same scene, with the focus set on each of the points of interest. You can then (try to) assemble the different pictures in post production.
There are two approaches to this:

simply use your favourite photo editing tool to assemble the pictures, taking good care of the transitions between them
or use "focus stacking" software that will (try to) do this automatically for you, giving you a much larger depth of field. You'll find a list of such software in the linked Wikipedia page, there may be others.

Note that changing the focus not only changes which points are in focus or not (blurred), it can also (slightly) change the relative sizes of the different objects, so this can make the operation quite challenging.
Also, I believe most focus stacking software is more geared towards assembling images with a range of consecutive focus settings rather than more extensive focus changes (e.g. a person at 1 m from the camera and a background several dozens meters away), but I might be wrong.
Comment: Thanks a lot Jcaron for the answer for I have been always thinking that it is possible and has asked many a people and they simply told that they don't know. By the way, focus stacking is a great technique that I can use for any further need.


on my 98 dakota the brake pedal sticks down i have to pull it back with my foot to release the brakes

Question: The brakes work fine but the pedal gets stuck down and I have to pull it back up with my foot to get it to disengage.  I have replaced the brake booster and the master cylinder. And the problem is the same.
Comment: Did you replace those parts or did you get someone to do it for you?
Answer: Generally, and I believe the 98 Dakota is no exception here, the master cylinder has an internal return spring that pushes the brake pedal back up when you release pressure on it.
Assuming that the master cylinder was actually replaced (and this is my assumption since you said it was) then the problem is elsewhere.
You should check the pedal pivot/hinge and the pedal to master cylinder linkage for binding or obstruction that made be keeping it from returning to it's normal position.
Beyond that, are you 100% the master was actually replace?  Was it a new/rebuilt or a used unit?  Did you do it yourself or was it done by a mechanic?
If you did it, you may want to pull the master cyl. and ensure that it's working normally.  If a mechanic did the work, then in my opinion, it's substandard work as I consider a "brake repair" job to end up with functional brakes.  It may be time to visit the shop and discuss the issue.


Do I have to do any setup if I want to run a VPN with the Tor browser bundle?

Question: I know there will be some votes against this but I want to run a VPN alongside the Tor browser. Can I just open the VPN program, connect to the VPN provider, then open the Tor browser and use it as normal? No extra setup required?
Answer: TL;DR: No extra setup required.
Concept:
Try to understand what Tor does. Tor builds a Proxy Chain for you to access the Internet. Your single request is routed through several different Tor nodes (known as relays) before reaching the host. The host only sees the IP address of the last node in your Proxy chain as the requesting IP address and returns the response to that IP. Diagrammatically, it would look something like this:
Your Machine ====> Tor Node 1 ==> 2 ==> 3 ==> 4 ==> 5 ==> Internet
Now what would happen if you also connect your machine to a VPN?
A VPN is like a tunnel which makes your OS believe that it is part of a private network, but the actual VPN server hosting this network may be a few hops away from your network. So effectively, when you connect to a VPN, all your traffic flows in the following manner:
Your Machine ====> N/W Hop 1 ==> 2 ==> 3 ==> 4 ==> 5 ==> VPN Server ==> Internet
Only the IP address of the VPN server is exposed to the Internet. Your VPN network adapter however remains oblivious to this route all it sees is:
Your Machine ====> VPN Server ==> Internet
When you merge run both VPN & Tor browser, the network path will look like this:
Your Machine ====> VPN Server ==> Tor Node 1 ==> 2 ==> 3 ==> 4 ==> 5 ==> Internet
Comment: ok, I have one more question. How does this order/way change if my VPN provider supposedly already connects to the Tor network? https://protonvpn.com/support/tor-vpn/
Comment: I would advise you to figure the rest out... It should be pretty elementary after the answer I provided above.
Comment: What I mean is, will being connected to a Tor VPN replace the normal tor connection? Or will it then go **Tor Entree Node ==> Tor Guard Node ==> Tor Exit Node ==> Tor Entree Node ==> Tor Guard Node ==> Tor Exit Node** and have it go through the Tor network twice?
Answer: This depends what you mean with "alongside". If you start your VPN all your traffic will be going over VPN, which means your setup is essentially VPN->Tor when using the Tor browser. Everything you do outside the Tor browser will of course only go over VPN.
So as to your question: yes you can open VPN and then use the Tor browser. This also hides the fact that you are using Tor from your ISP because your traffic first goes to your VPN and then to Tor. There should be no additional setup required.
If you're interested in Tor over VPN maybe this link will also provide further useful information:
https://blog.bolehvpn.net/tor-over-vpn-vpn-over-tor-which-is-better/
Comment: @NeoSkies So after reading it, just to be clear, I have to choose between trusting the VPN provider with my browsing data, or trust that the exit node I'm using isn't malicious? (P.S. I understand there are more pros and cons than that but that is the main issue for me).
Comment: That is correct. You should also note that if you browse sites that use HTTPS, a malicious exit node only sees the encrypted traffic. It really gets nasty when you browse a site that only uses HTTP, because a malicious exit node then sees everything, potentially also passwords. You should never enter any personal data while browsing non-encrypted clearnet sites with Tor.
Answer: You should definitely use a VPN while accessing onion websites for security measures and, of course, for anonymity.
The best solution would be to use a Tor over VPN server. In this way, you will connect to a VPN server first, and after that, you will have all your traffic routed to the Tor node. Plus, you will be able to access onion websites without the Tor browser.
You can read more info here: https://www.ibvpn.com/2017/02/maximize-your-privacy-with-tor-over-vpn/


Mac mini Mac OS 10.6 server migration to new hardware

Question: I have a Mac Mini with Mac OS X 10.6 Server installed. It has two external drives attached to it. One is for Time Machine and other contains data. I have bought the latest Mac Mini with Mac OS X 10.7 and two new hard drives. I want to migrate to the new hardware (the new Mac Mini and the new hard disks). Can Migration Assistant do that for me or do I have to transfer the data in the external drive manually?
Answer: Apple prepared a nice, long document listing the steps needed to prepare for and implement a migration from an existing Snow Leopard server to Lion server.
Have a look and come back and ask more specific question if you run into any snags...

Lion Server: Upgrading and Migrating For Mac OS X v10.7 Lion Server


Do I need an adapter to mount a Sigma lens to a Canon Rebel Ti3?

Question: I bought a Sigma 70-300mm  DG 4-5.6 Macro Zoom Lens for  my Canon Rebel T3. Do I need an adapter of some sort to be able to attach the lens to my camera?
Answer: Sigma produces same lenses for many different mounts, such as Canon, Nikon, Sony, Pentax, micro 4/3, etc... If you bought Sigma lens for Canon, than you don't need an adapter. If you didn't... well, why didn't you? It might be possible to attach it with adapter, and might not. but that depends on the particular mount your lens is compatible with (for example you may adapt Nikon lens to Canon, but not the other way around).
Comment: It's worth mentioning that in cases like this, it is probably a better decision to return a misadvertised lens than to go messing with adapters.
Comment: I bought the lens on eBay the seller said it was for a cannon EOS camera. However it will not go on my camera. Do I'm thinking it's not made with the cannon mount
Comment: I found online that the lens I bought isade for a sony camera is there an adapter that will allow it to fit on my cannon
Comment: @Beckgurl You might want to include photos of the lens mount and camera's body mount so that people can easier recognize the mounts and see what can be done.
Answer: Perhaps your lens was of the manual focus AE 35mm Sigma vintage, not compatible with AF Canon cameras without an adapter?
Comment: Unsure how your answer applies. OP states that their lens is a Sigma 70-300mm DG 4-5.6 Macro Zoom Lens. Sig makes lenses with different mounts so as to not need adapters. (most of their lenses come in the Canon/Nikon/Sigma mount variants)


Are there any specific laws and consequences for claiming to be God?

Question: Is there a specific command to not equate yourself to God?  For instance, someone says, "I am God."  This someone is a believer and a member of the Jewish faith, not an unbeliever.  I'm curious if Moses addressed this at all.
Comment: @AdamHeeg Since Judaism believes God doesn't have a physical form, a person who claims to be God is probably just a blithering idiot. Don't pay much attention to them. They are probably too ignorant of traditional Jewish belief or too mentally unstable to warrant punishment.
Comment: @AdamHeeg You are unlikely to find many references. Judaism (like most intellectual pursuits) doesn't spend much time listing all the stupid things someone could possibly claim.
Comment: Double AA thank you for the advice.  However, I'd like to know if there is anything specific written about this topic.  I came here to ask since my research was not able to turn anything up so far.
Comment: The only person who had such a claim made about him is called the "founder" of a nonJewish religion. If someone actually did make such a claim, then he would not be `a believer and a member of the Jewish faith`. The only reference in the Torah would be the reference in Deuteronymy to a false prophet.
Comment: Can I equate myself to the infinite? There is a difference between imagination and philosophy. If I write a book, what is happening in the book is the fact of G_d for the fictional persons. So I equate myself to G_d. But the reality is not my book and I don't equate myself to G_d. In some psychotic states I can have delusions as being G_d, after a good treatment it will go away.
Answer: The great Torah scholar and codifier of Jewish law, the Rambam (R Moshe ben Maimon, 1135-1204) compiled what he calls the "Thirteen Fundamental Principles of the Jewish faith", as derived from the Torah. They were to him "the fundamental truths of our religion and its very foundations." (from here).
Some have challenged to what extent everyone always agreed with all of them, but to a large extent they represent the foundational beliefs of every traditional Jew.
The first four principles are

Belief in the existence of the Creator, who is perfect in every manner of existence and is the primary cause of all that exists
The belief in God's absolute and unparalleled unity
The belief in God's non-corporeality, nor that He will be affected by any physical occurrences, such as movement, or rest, or dwelling
The belief in God's eternity

These principles are completely and fundamentally opposed to the idea that any man could be God. As such any person claiming to be God could not be called a believing Jew in the traditional sense.
Comment: Very fantastic answer and I hope to find some time to review your reference for other topics as well.  Thank you for taking the time to respond.
Answer: given the many verses which contradict you such as "no man can see me and live" (Ex.33:20) you will probably be seen as a lunatic at best and perhaps get lashes by the Rabbis for a start.


(Energetics) Potential Energy and Kinetic Energy

Question:
This question came up when I was reviewing the energetics unit. In my notes I wrote "systems with a lower potential energy are more energetically stable, because they have a higher kinetic energy and higher kinetic energy means higher level of disorder." Is this correct? If so, does it mean potential energy stored in chemical bonds are converted to kinetic energy during a chemical reaction?
Is energetically "stable" the same thing as energetically "favourable"?
Comment: 1) no, lower potential energy just means lower energy overall which is energetically stable. kinetic energy does not come into play at all. 2) basically the same meaning, but there is a subtle difference, you can call a molecule energetically stable, but you call a process, or a reaction, energetically favourable. e.g. benzene is stable, the formation of benzene is favourable.
Answer: In classical physics, kinetic energy and gravitational potential energy are almost interchangeable.  You do work on a ball and throw it vertically into the air.  Neglecting friction with the air all the kinetic energy becomes potential energy.  However, it then begins to fall, converting the potential energy back into kinetic energy.  Again, with no friction, the kinetic energy is exactly the amount that you began with.
However, we have to be careful to distinguish between ordered kinetic energy and random kinetic energy.  The ball, thrown into the air has both ordered and random kinetic energy.  The energy that becomes potential energy was the ordered form where-as the random thermal motions of all the individual atoms, which add up to no NET motion of the ball, remained the same throughout the entire flight of the ball.
But did they?  Again and again we have to say in these situations: Ignoring friction.  Friction does in fact exist when there is air present, and friction is very relevant to this discussion.  Friction actually converts ordered kinetic energy of motion into random kinetic energy of various particles (air molecules and ball molecules).
The creation of random motion from ANY other form of energy increases entropy and reduces the amount of energy that is available to do useful work.
I'm not sure that totally answers the question.  I think that the statement needs to clarify that random motion and its associated kinetic energy is, as your note claims, a preferred state over potential energy.
Comment: BTW: We usually call the random kinetic energy, THERMAL ENERGY.
Comment: Thank you! I think I need to do more reading. But I was wondering if anyone could explain this in a more Chemistry point of view.


What do you think about having very different tones in a single story?

Question: What if a chapter is incredibly depressive, dark, with intense language. And the next reads almost like a dialogue from a Seth MacFarlane comedy. Or even better, what if the tone switches occur between scenes.
I think most books I've read maintained a consistent mood, even if the characters emotions were flipping. So what do you think about breaking this rule?
Answer: You could get away with drastically different tones if you had two different POV narrators. If one is Tina Fey and the other is Sylvia Plath, they will of course see the world differently. The contrast will probably make your book lean more towards humor/dark humor/satire, so as long as you're okay with that, give it a shot.
This is not the same as a lighter passage in a bleak book or a dramatic scene in a funny book. We're talking about entirely different tone, vocabulary, and imagery.
I would not have a third-person limited or omniscient narrative voice which changes from Fey to Plath without explanation. The whiplash would be off-putting.
Comment: That's what I wanted to say.
Answer: You don't want to break the reader's immersion.
With your writing, you build the reader's identification with your characters and his expectations about the future progress of the story. If your characters suddenly act out of character, they become unbelievable. If you story progresses in a random fashion, your readers will be confused.
Sure, life isn't always the same, and in long novels the characters often are granted a respite from their toil, so that they can tell campfire tales or make love, but these interludes have meaning in the overall storyline, they fit the internal logic of the fictional world, and they usually don't completely fall out of the rest of the narrative stylistically.
On the other hand, there are books that break all the rules and do whatever they want. Apparently there are people who buy and read them. I cannot say much on these, as I cannot bring myself to read them, they annoy me so much. If you like them, you should ignore my advice and probably know much better, what you want to do.
Answer: In Shakespeare's Othello, Othello's speech often changes tone between scenes. He often sees himself as uncivilized however his tough is quite the contrary. However, in some scenes his language becomes more "brutal".
This was just an example, I think that changing the tone of dialogue in a character can both allow the reader to identify the mood of a situation. For example, if a character who is always optimistic suddenly starts contemplating his life and mortality it would allow the reader to see that this character is in a perhaps "grave" circumstance.
This question allows for a lot of opinion and this is just mine, you may find some people who think that changing a characters tone is "inconsistent" with the story.
Comment: Shakespeare's plays were performed in a bar-room-like revelry and had to appeal to both simple drunkards (so lots of below the belt jokes) and sophisitcated courtiers (so lots of erudition). His plays are not fitting blueprints for literature today.
Comment: @what Shakespeare is "not fitting blueprints for literature today"? Do you kiss your mother with that mouth? ;)
Comment: @LaurenIpsum Huh? My English must be failing me. Was that foul language?
Comment: @what I'm teasing you. You're saying *Shakespeare,* who is considered the greatest English writer of all time, is no longer appropriate as a role model. I'm joking that your comment is so wrong that it verges on profanity. :) (Obviously that's not true, and I'm just joking.)
Comment: Shakespeare is considered at all only by scholars (and pupils in English tests). The average reader doesn't read Shakespeare. The greatness of Shakespeare (or Goethe or Proust) is a fiction perpetuated in elitist circles. Enid Blyton is probably read more than Shakespeare. As a writer, you should rather study her. Or Twilight.
Answer: If you switch narrative tone, it will distance the reader and make it harder for him or her to achieve suspension of disbelief.  If you are writing a post-modernist novel, or a post-post-modernist novel (say, a fable about life in a you-tube-saturated short-attention-span society), this might be a good thing.  Otherwise, it is probably something to avoid.


Does hot water make more foam?

Question: A message has been floating around saying that it is better to wash your hands with warm water, as it helps the soap create more foam.
Is it true? If it is true, why is it so? Is there a temperature dependant factor in the soap's cleansing mechanism?
Comment: Foam is hardly relevant at all. It might be true that warm water cleans better, though.
Comment: @Waylander A virus particle is hardly a fat, and soap does not chemically break down fats either. ???
Comment: All chemical processes have a temperature dependance, higher temperatures increase reation rates. The breakdown of fats (including virus particles) by soap is a chemical process.
Comment: The lipid bilayer is similar enough for someone who is not a chemist, as is the dispersal of fats by detergent
Comment: At high temperature, the dissolution rate of any substance in water is greater than at low temperature. This has nothing to do with the nature of the solute, soap or not soap.
Comment: https://chemistry.stackexchange.com/questions/113103/does-the-main-washing-effect-of-soap-come-from-foam
Answer:
Is there a temperature dependant factor in the soap's cleansing mechanism?

Yes, because hydrophilic-hydrophobic interactions are always driven by entropy. Entropy contributes to Gibbs Energy which is the final quantity determining whether a reaction takes place or not (or in which direction it takes place for that matter). But your question implies other questions that should be answered.
Does soap create more foam with warm water?
I don't know. In general, mixtures exhibit phase separation at a lower temperature bound of miscibility and a upper temperature bound of miscibility. Some mixtures do not have a temperature range where no phase separation occurs, some are miscible in all circumstances, you get evaporation/freezing before you get phase separation, think water and acetone.
Does more foam in my soap help clean my hands?
No. Foam/bubbles are small sheets of water with surfactant towards the gaseous phase on the in- and outside. Hence the oily look and texture. What you cleans your hands is the surfactant, because it also helps solubilize hydrophobic stuff like certain proteins. The cleaning is done by hydrophilic stuff being dissolved in the water, and hydrophobic stuff being covered inside micelles of the surfactant, which are soluble in the water.
Does more soap help against viruses?
If your hands are really dirty, maybe. Surfactants are known to denature proteins. You wish to denature the virus proteins so that they can no longer carry out their functions. This would also rob your skin of its protective fatty outside layer. You need not worry to denature your own proteins unless you are trying to drink soap water. Also, aggressive surfactants like SDS work better than your standard fatty acid soap, being even more damaging to your skin as well.
How can I optimally protect myself against viruses on my skin?
Use a desinfectant like ethanol or iso-propanol with at least 70% concentration. It denatures proteins quite effectively. Usage for at least 30 seconds is the official recommendation to kill most common viruses and bacteria. I personally don't wash off, but wait for it to evaporate, which is a good heuristic for the 30 seconds. Make sure to use some sort of lipid replenishing cream every now and then to recover your skin.
Comment: The T-dependence of a reaction (whether it shifts to the left or right, and by how much, as the temperature is changed) is determined by the T-dependence of the equilibrium constant (Keq), *and the T-dependence of Keq is determined by the sign and magnitude of the enthalpy, not the entropy*.  Yes, the T-dependence of the Gibbs free energy is determined by the sign and magnitude of the entropy, but Keq  is related to the Gibbs free energy through a factor of T, which shifts the T-dependence from the entropy (in the Gibbs free energy) to the the enthalpy (in Keq).
Comment: @theorist higher temperature means higher entropic contribution to reaction directionality, no matter how you put it. Either it increases the factor in front of dS or it acts as a divisor for dH.
Comment: Nope, that's incorrect.  The entropy has *no effect* upon the T-dependence of the equilibrium constant (i.e., upon the first derivative of the equilibrium constant with respect to T).   The T-dependence of the equilibirum constant is given by the van't Hoff equation:  $\frac{d ln K_{eq}}{dT} = \frac{\Delta H}{RT^2}$  Note that $\Delta S$ is not present in that equation. To understand why $\Delta S$ disappears, you should go through the van't Hoff equation's derivation.  This can be found in any good pchem textbook.
Comment: If something is not present in the first derivative of something, it could as well have a constant contribution to an quantity, right? The van't Hoff equation shows that with rising temperature, the contribution of enthalpy to the equilibrium constant approaches zero.
Comment: Now you're confusing two different things, the T-dependence of Keq, and the value of Keq.  At the beginning of your answer, you were saying there is a T-dependence in Keq because of the entropy, which is wrong, as shown by the van't Hoff eqn.  Now you've switched to talking about the value of Keq itself, which does depend on the entropy change, but misapplying the van't Hoff equation to the value of Keq, when in fact the van't Hoff equation is for the T-dependence of Keq.

Does hot water make more foam?


Refrigerator water line leaking even though not hooked up

Question: I recently moved into a home and decided not to hook up the water line to my refrigerator. It was fine for a few weeks, but there appears to be a leak. Now the tube that flows from the water valve is leaking water. I'm not sure what needs to be fixed. Is it the water valve itself that needs to be replaced? I'm pretty sure the valve is turned off because it wasn't leaking before.
Answer: If you are talking about the water supply to the fridge from the house the valve may have been bumped. If you can find the valve try and turn it off "lefty loose right tight" (I still have to remind my kids that sometimes LOL). If you find a Saddle valve that looks like this these are notorious for leaking at the connection point and dripping when not connected. the valve may need to be replaced. Hope that helps.
At first I thought you were talking about the fridge itself but after re reading revised, putting both in just in case.
If the water is dripping out of the tube on the refrigerator where you normally supply water to it, it will stop soon. Once a little air got into the tube the system started to empty out. To speed things up pull the water filter if it has one and trip the water in the door these will remove some water and allow more of the water in the system to drain out quickly.  There is nothing wrong or to worry about.


Where to buy a SIM card at Ben Gurion airport, Israel?

Question: Are there any places to buy an Israeli SIM card when at the Ben Gurion airport, in Israel?
Answer: Based on a trip in December 2018, after posting my question, I can report there is a booth in the non-secure area of the terminal, on the ground floor (near the exit from the arrival/baggage claim/customs area) that sells 019mobile.com SIM cards at a 66% mark up over their website prices ($50 vs $30) for 2 weeks with unlimited international calling and 2 gig data.  The booth is convenient to get to and they put the sim in your phone for you. The sim card I purchased had a cell number that becomes inoperative after the 2 weeks of service I purchased.  Probably there are better plans (with this or other vendors) for people who will be visiting Israel often, that let you keep the same number, but that type of plan was not offered to me.
Here is the booth, and a map of the ground floor:
Comment: What a rip-off. [Drimsim](https://drimsim.com) would only charge you 20EUR for 2 gigs of data and there are no time limits. Plus you can use the same SIM card in other countries.
Comment: Yes, the SIM does not have an expiration date and does not charge any subscription fees. In the US they use AT&T.
Comment: @JonathanReez   This looks really interesting!  By no time limits, do you mean you can have cell service forever with one purchase, as long as you do not use up the data or minutes? (I could not tell from their English website.)
Comment: @JonathanReez  Can you tell what carrier they use in the USA?
Comment: @JonathanReez. The sim gives you a local number in only one country.  Or is there a way to get a local number in more than one country (with one sim)?
Comment: You only get a UK number, that's true. But personally I never give out my number to anyone as a tourist.
Comment: @JonathanReez.  Oh.  An Israeli number is much more useful when traveling in Israel. Back to 019mobile.com.
Comment: Added a photo and a map. Also, $30 is still a massive rip-off - see my answer.
Answer: In addition to the 019mobile booth, there's this vending machine on the ground floor of the airport:

next to one of the exits, which sells prepaid mobile SIM cards. I haven't checked the prices myself recently, but they are reported to be exorbitant (news item is from 2016). Note the 019mobile prices are also quite high.
 For reference only, and not at the airport: You can get a decent prepaid card for 30 NIS (the HOTTalk package by Hot Mobile: 500 min voice, 500 SMS messages, 5 or 10 GB data, not exactly clear; expires in 10 days). 30 NIS are under 8.5 USD. Again, this is if you actually go to a HOT Mobile store/booth.


Toilet flushes slowly, water comes all the way up, then water goes low, shower drains slow, but sink is fine

Question: When flushing my toilet the water comes all the way to the rim, sometimes it sits then drains slowly, sometimes I have to plunger it or sometimes it flushes ok but then the water goes way down to the siphon part of the toilet. I also have a shower in same bathroom that has started backing up and then slowly drains out. But the sink in same bathroom drains fine but all drains gurgle. I have a septic system 1500 gal tank emptied in 2016 had five people living here for 2 1/2 years only two now for a year. Looked in my septic tank and when toilet flushed or ran water I could barely hear a trickle coming from house. Stack, clog or main pipe clog?
Answer: Gurgling sounds like the air vent might be clogged.  That would make the drains move slowly, but not that slow.  It might be time for a cleanout of the main drain pipe.  Also have you been treating your septic tank?  Mom & Dad's backed up after years and it was actually due to powder laundry detergent plugging the main drain leading to the septic tank, but because they had been putting the enzymes in it, the tank was clean.  Once they broke the laundry detergent clog loose, the house drained properly.
Answer: I would be running a snake down the main line from the toilet, depending on the plumbing the sink could be downstream from the plug. Normally the toilet location is where the vent connects so if it backs up the vent line can be flooded . Running from the toilet is usually the easiest access and only cost a wax seal.  A plunger knocking it loose sounds like a better case for a big snake so you can pull the clog out instead of have it move it around.
Comment: Ed is right. Just be aware that he is talking about removing the toilet first. You don't want to run a snake down through a toilet - it could damage it. As he said you'll need a new wax seal on the flange.
Comment: Thanks @honeydo, sometimes I forget to explain all the basics+


If mastered enough, could Haoshoku Haki destroy a large piece of land, maybe crack an island in half at most? (One Piece)

Question: I was curious because Shanks was cracking parts of Whitebeard's ship just from his presence, so couldn't that mean if mastered enough it could have more of a destructive power to physical objects instead of the mind when mastered enough?
Comment: It can go as powerful as Oda-sensei wants it to be.
Answer: We have no way to answer that because we have not been told by oda if that is possible and we have not seen anything on that level the closest we have seen is when shanks cracked a part of whitebeard ship.
Comment: I did not want to leave you hanging so i gave you the best answer i could sorry :(.
Answer: From the fact that "Channeling a haki, able to produce the more power", I don't think so just simply releasing it 360° from your head would do any good damage! Even mastered haki user Shanks could do so far!
But yes, channeing that same energy of Conquer Haki into your sword can swinging it, probably can destroy a island to half (if you chaki is that much powerful)!
Ref: Roger vs Newgate


Can I connect Nikon D90 to Samsung grand duos smartphone?

Question: Can I connect my Nikon D90 with Samsung grand duos (running Android Jellybean 4.1.2), using HELICON software remote?
Answer: If you take a look at the Helicon remote website it makes it pretty clear: http://www.heliconsoft.com/heliconsoft-products/helicon-remote/
It is compatible with the Nikon D90 and Android 3.1+. It sounds like you have both. It should be compatible.
Note, you do need Helicon Focus Premium license for usage with phones.
Answer: You can use the setup you describe. To connect the Samsung to the Nikon, you will need an OTG connector, to setup the Samsung (micro USB) as host and the Nikon (mini USB) as the client.


Why do stars have absorption spectra?

Question: Absorption spectra are a result of light of a certain wavelength exciting an atom from a lower energy level to a higher one and at the same time being absorbed. However, the atom should eventually go back down to its lower energy state, and at the same time emit a photon of same frequency it absorbed earlier. Overall, no changes to the star's spectrum should occur.
Answer: A similar explanation, is that the intensity at any given frequency is the optical depth weighted average of the plank (black body) function. As the light ray goes deeper (maybe comes from deeper down is more intuitive) for each delta in optical depth the local temperature determines the ratio of emission to absorption. In the center of an absorption line, the opacity is higher, and thus the depth in the photosphere for a given optical depth is less than it is outside of the line. Since in the photosphere, temperature decreases with height, the spectral lines reflect a lower emission temperature. A more intuitive, but less exact way to think of it, is to consider the beam of light to be formed at an optical depth of unity. In the center of an absortion line, that depth is much less, so the strength of the plank function is much lower (reflecting the lower temperature higher up in the stellar atmosphere).
For very very strong lines, you can get the opposite effect -emission lines, as the temperature in the stars chromosphere and corona increase with height, and the closer to the line center you are the higher the effective height of formation.
Answer: When the energy level drops and the photon is re-emitted, it is scattered or re-emitted in a random direction, so less of that frequency reaches your telescope/spectroscope. It is sort of analogous to the "why is the sky blue" question. What you are looking at is direct line photons(line of sight), so photons passing through the star's gaseous layers are depleted in this line of sight by the random scattering.
Comment: As Omega Centauri points out in his answer, the crucial extra ingredient is that the deeper layers of a star have higher temperatures than the outer layers. If a star were at a uniform temperature, then there would be no absorption lines: as many photons would be scattered into your line of sight as out of it.
Comment: What do you mean "random direction"? Stars are spherically symmetric, the photons are already going in random directions.
Comment: @Itai ---photons heading from the star straight to your line of sight are absorbed by gas in their path. The re-emitted photons are rarely re-emitted directly in their former path, hence, they are scattered, so fewer of those original line of sight photons reach your CCD or spectrometer.
Comment: @TedBunn another pop-sci myth nailed.
Answer: Stars have plenty of "cold" gas (atoms in their ground states). If you put some gas on the way from a light source to you, some frequencies will be less represented (dark absorption lines) than non resonance frequencies. Atoms for such frequencies are like a fog on the light way - they capture and diffuse the resonance frequencies to the whole solid angle $4\pi$. So you observe them as less represented than the neighboring non resonance frequencies in the continuous spectrum.

Why do stars have absorption spectra?


Gluteus Maximus Development Tips For Men

Question: I'm 29 years old, 5'10", 165 pound, 12% body fat percentage man. I have so small Gluteus Maximus size and I want to gain some size there. I do hip thrusts, glute bridges, squats, deadlifts, hyper extensions and any variation of lower body exercises for gluteus, I consume 2.2 times kg of LBM protein from highly bioavailable sources, enough macro and micro foods but still not enough result. I don't believe about genetic limit if you are not IFBB level. So i need some tips and advices about gluteus development techniques(not about how to do a good diet).
Comment: What do you squat and hip-thrust? Hip-thrusts are the single best way to target the gluteus maximus, so if you're not gaining there it might be you aren't lifting enough.
Comment: Have you tried a regular diet of kettlebell swings?
Comment: What about IFBB suddenly implements a "genetic limit"?
Answer: So your objective is to build muscle, in this case glutes.
To build muscle you need to stress those muscles the proper way. In this case, the proper way would be adequate repetitions  (8-12) and adequate series (4-5) therefore defining the weight to be used depending on the exercise. That is up to you to define. The exercise selection you provided is adequate altough you might want to experience with some sprinting-focussed training (so ... sprinting, jumping, ...) or other glute-focusses exercises like clam-shell, ...
A second parameter you can play with is the kind of muscle contractions. To build muscle, focus on eccentrics (eccentrics tend to increase hypertrophy) so do slow tempo on the eccentric part and then fast tempo on the other parts (isometric and concentric). For a squat, this would mean something like 4 seconds on the descent, 0 seconds isometric, 1 second concentric, 1 second pause and do that all again.
Now in training, routine usually is the enemy so mix it up. Change the tempos, do 1 week eccentric, 1 week isometric, 1 week concentric
Third thing is having the right frequency of training too much or too little and you won't get the gains you want. Again, up to you to determine that. Also pay attention to all the other training you are doing. Performing aerobic exercises during/near your strength training have been shown to impede the signaling pathways for strength gains.
Finally, make sure you are actually using your glutes during the movements and not using other muscles. This requires self-awareness and focus on your part. Or you could use other exercises to fatigue the muscles around your glutes then perform the glutes-focussed exercises to make sure they are actually doing the work. Using electrostimulation during exercises could help a little but this is expensive and not 100% certain it will work.
Answer: If your looking to increase your glute size focus on deep squats. That is squat low, below parallel, the lower the better without compromising your back arch.
You also must squat heavy. You are 165lb, and I don't know what your lifting, but a good goal is to shoot for ~305lb for a couple sets of 12. If getting bigger glutes is your primary goal right now, you should be squatting 3 times a week. Do a heavy-light-medium rotation of the weights and reps. When the weight is lighter do more reps, shoot for 15. When it's heavier do less reps, shoot for 8 minimum.
Every week try to increase your weight across the rep range. You should be able to push yourself like this for 6-8 weeks before needing a break, and that should be enough time to tell if it's working.
Don't get yourself tied up in doing endless sets. 2 sets is fine, just push hard, and get the reps with the heaviest weight you can safely lift.
As for diet, if you are training as hard as I list above, then you should be eating a MINIMUM of a gram of protein per pound of body weight every single day. Doesn't matter how many meals it takes to get that into you.
You also need to increase your caloric intake if you are pushing this hard on squats. Simple rule of thumb, if your really sore, your not eating enough. But you have to eat good food. Filling up on junk food just to get calories in will just make you fat.
You will have to drop all other exercises for the lower body. This is ok, as the squat provides excellent overall development for the legs.
Be warned, you will have to buy new pants. Just getting into high volume heavy squats will start your legs growing like weeds IF YOU EAT. I did about half this much squatting when I was prepping for a powerlifting meet, and I was NOT trying to increase leg size as I needed to stay in my weight class, and I still ended up breaking 2 pairs of pants in a 6 month period. I had to to stop drinking water for 12 hours to make weight.
Heavy squats make you grow. Plain and simple.
Comment: I tried everyday squat also and the weight you said for my size is not realistic for me. 2 times of my weight and 12 reps deep squat. That's insane!My PR for 1RM deep squat is around 250 pounds. I know like 2 times body weight 1RM squat is beginer competative standard. https://www.muscleandstrength.com/articles/strong-strength-standards-raw-natural-lifters To reach that numbers that has to be your only job(I'm office worker).Sorry but this not what I asked,I need tips, not the methods and diet information that I already know about.I'm asking something like technique,tricks for lifting heavier.
Answer: Some say diet is much more important than training regime. What are you eating on a daily basis?... number of calories, grams of protein carbs, fats?
Based on the science, I require 244 grams of protein a day in order to grow, when working a training program. (Google "protein intake calculator" for your amount).
That's 80 gms each meal (3 meals/day), or 60 gms (4 meals). One large egg is about 6 gms, so I eat at least 8 eggs for breakfast. I eat 5 meals, counting my post-workout protein shake... about 50 gms each meal.
At only 3 meals, I would require 13 eggs for maximum growth. And, when training hard, my body would need  every bit of it.
"They" say six meals is best... for metabolism, weight loss and to keep the muscles in a  constantly growing anabolic state vs catabolic.
We grow muscle in recovery, not at the gym. You can actually shrink if you're not giving the body what it needs. The body will catabolize existing flesh, organ tissue including the heart (that's what eventually kills the anorexic).
Bottom Line: If you want to get big, you gotta eat big. And, you gotta rest... get plenty of sleep and naps are good too!
Good Luck!
Comment: I suggest you to read that and find a realistic calculator Liam https://bayesianbodybuilding.com/the-myth-of-1glb-optimal-protein-intake-for-bodybuilders/ My problem is not growing, my problem is not growing in that specific place. The things I want to learn about is more like technique.
Comment: CanESER, you are absolutely right. Thanks for correcting me. The other detail often overlooked is the fact that the myth says, "per pound of BODY WEIGHT," when it's actually, "per pound of LEAN BODY MASS (LBM)."
Comment: So, for me at 240 lbs, the myth had me striving for 240 grams of protein per day... most of which prolly turns to fat, not to mention abundant ketones, kidney damage, an acidic environment prone to cancer and who knows what else!
Comment: So, I found a LBM calculator... http://www.calculator.net/lean-body-mass-calculator.html. I'm fat, so my LBM is around 150 lbs. Think about it... extra fat doesn't need extra protein... just the recovering muscle. And, you pointed out that none of the research supports any more muscle growth over 0.75 gm protein per pound of LBM (and likely more like 0.69). Therefore, I only need about 105 grams a day instead of my crazy 240. Thanks for setting me straight. Any luck on your original question?


How to make the Tor Browser take the same identity each time

Question: I use Tor Browser in Ubuntu. I want to learn a way if possible to make the Tor Browser take the same identity each time I open it. Is it possible?
Comment: Why would you want to do that, it largely defeats the purpose of Tor. It sounds like you may want a VPN instead.
Comment: No, i don't want to do that. I'm just asking for knowledge if it's possible to do that
Comment: That's fine, but explaining why you want to do this might help get a better answer.
Answer: I interpret your use of the phrase "take the same identity" to mean that you want to have the same IP address (of your exit node) as in a past Tor session. In that case, the answer to your question is "Yes, but only indirectly".
Locate and edit your "torrc" file.
Add one new line to it, that says:
ExitNodes SomeExitNodeName

In the place of SomeExitNodeName include the Name of the exit node that is at the IP address that you want to 'be'. Then stop Tor and restart it.
You can lookup the ExitNode name at http://torstatus.blutmagie.de/
If you cannot find the IP address you desire on that page then the party who previously hosted an exit node on that IP address is no longer doing that, so in that case you're out of luck.
Answer: pabouk is correct, I made mistake when I read question.
always the same identity is related to exit node, so, you can choose exit node in your torrc file. just find IP address you want (for example like below) and write:
ExitNodes 10.100.234.333
StrictNodes 1

in that way you will always get the same exit node, if you don't write strictnodes 1, tor can override your torrc parameters. theoretically if you pay some server anonymously with bitcoins and you make tor exit node, you can always use it for yourself, just add mentioned changes in your torrc file.
Answer: why he would do it is not valid question. for example I don't believe 100% to tor bridges and would make my own private bridge to connect to tor nodes.
so, my answer: I am not professional, but I think you can make your own obfuscate bridge and use it to connect to tor network.
I suppose you would have to rent vps if not dedicated server, install obfuscate bridge and configure it to refuse to send information to tor developers so it will not be listed and known anywhere, then use at your PC: Pluggable Transports Tor Browser Bundle (https://www.torproject.org/docs/pluggable-transports.html.en). you can try to include only one obfs bridge, your one. I never tried, you can try it. bridges are written in torrc-defaults file.
Comment: @blah If you think your question is not correct, consider deleting it.
Comment: I think that Helpy understood the question correctly and that it is about how to use an exit node with the same IP address all the time.


is there any way to make an earthlike planet (aside from the atmosphere) have a green sky at noon and a pink sky at dusk

Question: im working on a mostly earthlike planet (aside from atmosphere) have a sky that looks green at noon to humans and pink during a sunset? could it be done via airborne algae? would the atmosphere still be breathable to humans?
Comment: You need to constrain the problem more.

What's allowed with the parent star? Does it have to have a solar G-type spectrum?

Any restrictions on lifeforms? Crust composition? Just how Earth-like does the planet have to be? Does it just have to have a 70/20 N/O atmosphere or does it have to look and feel like Earth (i.e. a big blueberry when viewed from far away)?
Answer: There are a few options to make the color of the sky change. To really get into the physics of this, you will need to get comfortable with scattering and emission spectra.
Firstly, the star hitting that system could just not emit as much blue light, resulting in the next color being more diffracted (and more visible) than blue. This has some downsides, such as blue things appearing black or very much darker than here on earth. If you went the route of having a less hot star or a star with significant amounts of certain elements, you could get a mostly-green emission spectrum. (The less intense heat can cause an issue here, though!)
Secondly, as you point out, you could simply have something in the atmosphere that reflects more green than blue. This has the added bonus of letting blue items remain visibly blue.
For instance, Algae are noted to be frequently green and occur in blooms- but then you simply have the problem of how they get their nutrients and stay aloft! It does seem reasonable that some enterprising micro-organism stumbles upon a way to ride the wind - they experience a much different Reynolds number than we do!
Finally, pink/red skies often happen because of particulates in the air. These conditions happen on earth already! You see odd colors of sunset when storm systems, large forest fires, or other particulates in the air are west of you during sunset.
Answer:
is there any way to make an earthlike planet (aside from the atmosphere) have a green sky at noon and a pink sky at dusk

Maybe!

would the atmosphere still be breathable to humans?

Erm, briefly?
There's a book called "Under A Green Sky" by someone named Peter Ward, who is attempting to describe how Earth would have looked during the boring billion,  according to the Canfield Ocean model.
Roughly speaking, the oceans were anoxic and filled with an interesting bacteria soup rich with sulphate-reducing bacteria and purple sulphur bacteria. The former group thrive in the oxygen-free oceans and generate vast quantities of deadly hydrogen sulphide. It filles the air and wrecks the ozone layer. Ward suggests that the concentration of the gas in the atmosphere results in a greenish sky, though I must confess I haven't been able to find any supporting evidence for that claim or how he worked it out.
The ocean surface is covered with a thick mat of the purple sulphur bacteria who photosynthesise and consume some of the hydrogen sulphide reducing it to elemental sulphur but producing no oxygen.
The colour of the Earth's surface often has influence on the colour of the sky and clouds above it, and certainly an ocean sunset on such a world would be pretty pinky-purple.
So! If Ward was right, not only is your world possible, but it has happened before and if the most pessimistic models of destructive climate change come true, it can happen again! It just isn't really somewhere that people are really going to want to visit, and not much is going to live there.
Answer: Insectoids
Every day after dawn, vast hordes of insect-like creatures with green-tinted, diaphanous wings fly up beyond the cloud layer to soak in the sunlight. The green in their wings is chlorophyll, and the sunlight helps them break down nutrients they have eaten through the night. In the evening, when sunlight fades, they descend to the ground to feed through the night, leaving the sky clear for a typical pink sunset. Their shit and decaying bodies fertilize the ground. It is a sort of symbiosis where plants get the use of photosynthesis secondhand instead of firsthand. Imagine plants sending their leaves up in the air to gather sunlight, and you're not far off. This symbiosis may have evolved because thick cloud layers often block out the sunlight or have in the past.


Centre of the Universe

Question: Why shouldn't the original singularity of the big bang happen to be the centre of the Universe? Assume that the universe is expanding isotropically with a constant speed.
Comment: Hi Jack and welcome to Astronomy on StackExchange.  Your question will likely be flagged as a 'duplicate' question (and closed.)  I can appreciate your curiosity... and that's a good thing.  I would encourage you to use the StackExchange search feature and enter 'center of the universe' to find many excellent answers as this question has been asked and answered several times.
Answer: (I can't comment)- See https://physics.stackexchange.com/questions/136860/did-the-big-bang-happen-at-a-point
TLDR, The big bang happened everywhere in the universe at the same time, because it was the universe. The top answer goes more in depth.

Centre of the Universe


How to get into space from northern latitudes?

Question: What would be the best way to launch space craft/get into space from a northern latitude? Canada, Scandinavia, UK, Russia, Alaska, those sorts of places. I understand that being closer to the equator gives benefits due to rotational speed etc, but what are the options for those not on the equator? Space elevator is out but what are the other options? Would a skyhook work? Space fountain? Just regular old rocket launches?  Which would be more energy efficient: fountain or launches?
Thanks!
Comment: Related on [space.se], our sister site for spacecraft operators, scientists, engineers, and enthusiasts: [On a Super-Earth 1.5x the volume and mass of Earth, would our rocket technology allow us to reach orbit?](https://space.stackexchange.com/q/5320/415), [Is space travel possible from a large planet?](https://space.stackexchange.com/q/17423/415) and [How much bigger could Earth be, before rockets would't work?](https://space.stackexchange.com/q/14383/415) (and others). See also [Is this a correct understanding of Tsiolkovsky's rocket equation?](https://space.stackexchange.com/q/13763/415)
Comment: *Which would be more energy efficient: fountain or launches?* - fountain, any time, anywhere
Answer: The difference isn't large, rockets will work fine
Escape velocity is calculated from setting the potential energy and object has in earth's gravity well equal to the kinetic energy it would need to escape from it: $mgh = \frac{1}{2}mv^2$. Since the mass of the object is the same on both sides, we can drop it and solve to get $$v = \sqrt{2gh}.$$
The force of gravity is not constant at different heights. I did my calculations accounting for the differences, and accounted for them in each equation. The exact radius of the earth at the poles (modeled by WGS-84) is 6356.752 km. Plugging into the above equation, escape velocity at the north pole is $$v = \sqrt{2\cdot9.854\frac{\text{m}}{\text{s}^2}\cdot6356752 \text{m}} = 11193 \frac{\text{m}}{\text{s}}.$$
The radius at the equator is 6378.137 km, and lets assume we get a free 465 m/s boost from the earth's rotation. Plug those numbers in to get
$$v = \sqrt{2\cdot9.788\frac{\text{m}}{\text{s}^2}\cdot6378137 \text{m}} - 465  \frac{\text{m}}{\text{s}} = 10709 \frac{\text{m}}{\text{s}}.$$
If we convert those two numbers into kinetic energy terms, it takes $6.26\times10^7\frac{\text{J}}{\text{kg}}$ at the pole and $5.73\times10^7\frac{\text{J}}{\text{kg}}$ at the equator with a rotational boost.
So escape velocity is 4.5% higher at the pole and escape energy is 9.2% higher. Significant differences, for sure, but no reason that rockets won't work.
Answer: Well, given that places such as the Pacific Spaceport Complex exist in Alaska... I'd say rocket launches.
If you want to use other options like sky hooks or space fountains etc. you are welcome to do so, but for the amount of space traffic we have today rockets are pretty much the only thing that has proved economical/feasible.
Answer: Just to add to kingledion's answer.
Its useful to launch from a location close to the equator if you want an equatorial or geo-stationary orbit, since you don't have to waste delta-v changing the inclination of your orbit.
If you want a polar orbit you can launch in a roughly north or south direction from anyway on the planet.
Alternatively you can launch due east from anywhere on the planet to obtain a inclined orbit at a specific latitude for example the ISS's orbits at 51.6 inclination to make it easier to resupply it from Baikonur Cosmodrome (45.95N).
As kingledion points out an easterly launch, helps but its not a show stopper.


Renaming of administrator directory

Question: Can be administrator directory effectively renamed (for example by simple change in Joomla! core code) for example to admTZ34? The main reason is to obfuscate standard pattern where www.example.com/administrator could be used to check presence of Joomla! installation (in older releases also Joomla! version etc.)
Comment: Before Joomla SE was set up I asked this same question here on SO: http://stackoverflow.com/questions/15034980/change-joomla-administrator-url
Answer: It's not really recommended or very simple to do. The admin path gets hardcoded in a lot of extensions with calls to things like JTables which means changing the directory name could have a lot of consequences.
That said if you want to prevent direct access try with one of this solutions:
A) Password protect /administrator with a .htaccess password protection.     This uses HTTP authentication to prevent anyone from getting to the admin directory.
http://httpd.apache.org/docs/current/programs/htpasswd.html
B) Require a keyword in the URL with an extension like:

AdminExile
JSecure
KSecure
Admin Tools
Admin tools is capable of doing both options for you.
With one of this extensions the admin url will be:
yoursite.com/administrator/?mySpecialPhrase
Comment: I don't believe so because .htpasswd will only check for http access. When copying files around via the installer I think all that happens at the server level so I don't think this will matter. That said, I have seen issues with things like javascript being stored in /administrator and being called via HTTP on the front end and asking users to login. So this isn't always a workable solution.
Comment: Quick question regarding your first point. Will protecting it using a .htaccess file prevent files being moved the necessary directories within the administrator folder upon installation of extensions?
Comment: @ChadWindnagle +1 from my side in your answer and your comments.  Backend Protection through htaccess is a good solution but few extension fetch site's images and javascript  from site's backend, In-that case htaccess restrict to access these images and javascripts.
Comment: Continue @ChadWindnagle answer
 3) Use two factor authentication http://extensions.joomla.org/extensions/access-a-security/site-security/login-protection/24822
Comment: Nice suggestion on 2 factor. That said I think it's in Joomla 3.2+ so an extension shouldn't be necessary if running latest version of Joomla.
Answer: You can't really change it as it would prevent extensions from installing properly. You can however use Admin Exile which allows you to add a value, key or both to the administrator URL. In addition to this, if the standard admin URL is typed it, it will redirect the user to a site of your choice.
http://extensions.joomla.org/extensions/access-a-security/site-security/login-protection/15711
Hope this helps
Comment: Extensions in general, not just plugins. There are also other reasons why you should not change the name of the folder. One reason @Chad explains regarding JTables
Comment: So if I understand, the main problem is plugins, right? Can it be said that Joomla! installation without extensions can withstand renaming of administrator directory relatively safely?
Comment: In addition to that, the whole thought process of renaming /administrator/ in general as a practice is not a good one. It's not "real" security. The author of Akeeba backup and a Joomla security expert wrote about a similar type of move regarding configuration.php [http://www.dionysopoulos.me/keep-your-files-where-i-can-see-them/] I'd recommend reading that to understand why this type of change is frowned upon.
Answer: If your only concern is bad-bots identifying your website as joomla website then you need to do a lot more to hide this truth.
A lot of technique exist to identify your website as joomla and its version.
This .htaccess file helps in these attacks.

Renaming of administrator directory


Where did the estimation rule of thumb originate that time spent will be one-third in each of the following: design, implementation, and testing?

Question: I'm looking for a reference to the following.  I commonly hear that one-third of a projects time will be spent in design, one-third in implementation, and one-third in testing.  The three phases of development seems to be derived from the waterfall model.  But, where did the time division originate (1/3, 1/3, 1/3)?  Is there a paper or book that this is from?
Comment: [Citation needed]
Comment: Bryan Oakley, you are asking my question.  I am asking for a reference when I ask, "Is there a paper or a book that this is from?"  What person originated this rule of thumb? Brooks (Mythical Man Month), Yourdon, etc.?
Comment: This was [discussed on MSO](http://meta.stackexchange.com/questions/158158/why-was-this-closed) prior to being migrated here. The way I read the question it's about finding the source of an oft quoted rule of thumb (I've heard the "1/3 rule" quite a few times myself), and _not_ about discussing its merits - we have a [ton of questions about estimation in general](http://programmers.stackexchange.com/questions/tagged/estimation?sort=votes&pagesize=50) were answers discussing the merits of various estimation techniques would be more appropriate.
Comment: What makes you think this is a standard rule of thumb? Can you site a reference?
Comment: @BryanOakley It probably isn't a standard rule of thumb, but I've heard it (or slight variations of) constantly since my early days in the field, a little bit over a decade ago. I'm certain I also read it somewhere online, but I can't remember where (and it probably was some blog or something like that).
Answer: The rule of thumb you're describing sounds extremely similar to Brooks' rule of thumb, as presented in the Mythical Man-Month:

For some years I have been successfully using the following
  rule of thumb for scheduling a software task:
1/3 planning
  1/6 coding
  1/4 component test and early system test
  1/4 system test, all components in hand.
This differs from conventional scheduling in several important ways:

The fraction devoted to planning is larger than normal. Even so, it is barely enough to produce a detailed and solid specification, and not enough to include research or exploration of totally new techniques.
The half of the schedule devoted to debugging of completed code is much larger than normal.
The part that is easy to estimate, i.e., coding, is given only one-sixth of the schedule.

I don't know where exactly your rule of thumb comes from, but it certainly looks like a derivative of Brooks' rule of thumb.


Is Tor a P2P network?

Question: I have a question regarding Tor that has got me a bit confused lately.
Could someone please tell me is Tor a P2P network?
Thank you.
Comment: I think that the only centralization point in Tor is the small group of Directory Servers, the rest of the network should be pure peer-to-peer
Comment: @flagg19 Yes, I am aware of the Directory Servers. But in a peer-to-peer system, users apart from using resources from the system also must contribute to it with their resources. I don't see how my Tor client contributes to it (it does not relay traffic, for example)? Any thoughts on this?
Comment: Every Tor client can be configured to do: 1) nothing but use the network to anonymize the computer it is running on, 2) also relay traffic but only to other nodes inside the network, 3) also relay traffic to the external Internet (exit node). If you are case 1 you're right, you're not really contributing, but in the other two cases you are. Note also that just for using the Tor network (even in case 1) you're helping the community by increasing the total number of users, see "Anonymity Loves Compan" http://freehaven.net/anonbib/cache/usability:weis2006.pdf to understand why this is good.
Answer: No, Tor is not inherently a peer-to-peer network. Tor is network of virtual tunnels an is therefore more like a virtual private network (VPN), but differs from the usual VPN in that the the tunnels proceed from your machine to another (the Entry Guard) and then to a second machine and from there to a third machine (the exit node) and finally, to the point to which you are really trying to connect (e.g., a typical website).
Although Tor is described as an "onion router" I think that it is easiest to imagine it as a series of hosepipes that have been threaded through one another.
To continue this analogy, imagine that you connect a very fat hosepipe from your machine to the Entry Guard. Because the hosepipe is opaque (encrypted) anyone who looks at it will have no idea what it contains, even though they might recognize the hosepipe as being a "Tor hosepipe". Having connected to the Entry Guard, you thread another opaque (encrypted) hosepipe inside the first, together with instructions to the Entry Guard about what machine they should push the second hosepipe along to when the end of hosepie-2 appears out the end of hose-1. So now we have hose-1 connected to Entry Guard, along with hose-2 inside hose-1 also reaching the Entry Guard, and hose-2 alone continuing from the Entry Guard to the next machine.
Repeating this process, having gotten hose-2 to the middle point, we push (encrypted) hose-3 inside of hose-2 inside of hose-1 ... and of course, hose-3 makes an appearance at the end of hose-2 along with instructions for the middle-guy about what she must do with it ... which is to push hose-3 to the Exit node. Finally through the triple hose-pipe, you send request for a web-page on its way. The Entry Guard doesn't know what the request is because it is hidden inside two more layers of hose (encryption) there is a double-layer hose (remember hose-1 only reached to the Entry Guard) that reaches to the middle guy. Middle guy also can't read the request but the smallest of the hoses connects to the Exit Node where your web-request makes an appearance. So the Exit node can now send your web-request to the appropriate web-site and receive the reply ... which he sends back down the pipe to you the way it came.
I hope the analogy is helpful rather than even more confusing. It might also be worth looking at the Wikipedia link I included because it describes things about "tunneling" generally.
There is something else to add: you appear to be asking a question that confuses two very different concepts, a bit like asking "Does it use HTTP or TCP/IP?" or "Does it use wire or is it digital?" when in fact some things with wire are analogue and some are digital, and some things that are digital use wire connections and some use wireless. The questions are ill-formed because they presume that the things that are being compared are of equal status or fulfill similar functions when in fact they do not. Consider this: it is possible ... don't do this, but it is possible ... to run BitTorrent over Tor. BitTorrent is a protocol for peer-to-peer file sharing, and Tor is a network of virtual tunnels. Clearly one thing (Tor/BitTorrent) does not exclude the other (BitTorrent/Tor).
Comment: @flagg19 I just found the Tor design paper. On page 4 under 'non-goals' it says 'not peer-to-peer'. So according to this, [link](http://www.onion-router.net/Publications/tor-design.pdf), Tor is not a peer-to-peer network.
Comment: Yes but as flagg19 said it can be configured to function as a client and as a relay, which makes it function as a client and as a server, respectively, which is basically a definition of peer-to-peer.
Comment: @Visi well, thanks for letting me know, I guess one never stop learning :)
Comment: @flagg19 Your welcome :) But to confuse me a bit more i just found [this](http://www.researchgate.net/publication/265645745_The_TOR_data_communication_system), where it kind of states that Tor is a peer-to-peer network! I guess i just have to stick with the original design paper, until i can really clarify this.

Is Tor a P2P network?


Is loading a built exe from QT Creator different from loading the exe from file system? [webkit issue]

Question: I'm writing a desktop app that connects to my company's intranet. The page I'm trying to load is HTTP, but it will redirect to a login site that uses HTTPS. The app loads the page well when launched from QT Creator (both redirection and authentication succeeded, and the page is shown correctly), but when I run the app from file system (all DLLs are put into the folder correctly), the loading fails (QWebView's loadFinished(bool) signal is emitted with a false, which is a rare case as I learned online). I can catch the first 302 redirection status from QNetworkManager's SIGNAL(finished(QNetworkReply*)), but when the second time the signal is captured, the status becomes invalid. From QNetworkReply's documentation I read that "If the connection was not HTTP-based, this attribute will not be present." I don't know why. In addition, not SSL error signal is emitted. Since the app runs well from QT Creator. I believe it should be due to some difference in environment when launching. Anyone have a clue? Thanks!
Answer: No experience with QTCreator, but check for permission issues?
Comment: QT creator is not running with privilege. One thing is that the app runs ok from FS several days ago but fails now. (I tried the backed up build from several days ago recently but with no luck) I don't know if that's some server side problem since I tried on multiple computers, which all managed to run the app before. But the most weird thing is why it has no problem when launching from IDE.


Prove by induction that $3^{3n+1} + 2^{n+1}$ is divisible by 5

Question: How do I do this? I've tried using logarithms, factoring, but nothing seems to work.
Answer: Hint for the inductive step after the basis case:
$$3^{3(n+1)+1}+2^{(n+1)+1}=27\cdot3^{3n+1}+2\cdot2^{2n+1}=$$
$$=2\left(3^{3n+1}+2^{n+1}\right)+25\cdot3^{3n+1}$$
Answer: You can use modular arithmetic :
Suppose $3^{3n+1}+2^{n+1}$ is divisible by 5, then
$3^{3n+1} \equiv -2^{n+1}[5]$
so you have
$$3^{3(n+1)+1}+2^{n+1+1} \equiv 27 \times 3^{3n+1}+2 \times2^{n+1} [5]$$
$$3^{3(n+1)+1}+2^{n+1+1} \equiv 27 \left(  -2^{n+1} \right) +2 \times2^{n+1} [5]$$
$$3^{3(n+1)+1}+2^{n+1+1} \equiv -25 \times2^{n+1} [5]$$
$$3^{3(n+1)+1}+2^{n+1+1} \equiv 0 [5]$$
Answer: HINT:
If $f(n)=3^{3n+1}+2^{n+1}$
$$f(m+1)-a\cdot f(m)=3^{3m+1}(3^3-a)+2^{m+1}(2-a)$$
If we set
$3^3-a=0\iff a=3^3\implies f(m+1)-3^3f(m)=\cdots\equiv0\pmod5$
or
$2-a=0\iff a=2\implies f(m+1)-2f(m)=\cdots\equiv0\pmod5$
$\implies5|f(m+1)\iff5|f(m)$

Non-inductive methods:
$(1)$Binomial Expansion:
$3^3=25+2\implies3^{3n+1}+2^{n+1}=2^{n+1}+3(2+25)^n$
$=2^{n+1}+3[2^n+\sum_{r=1}^n\binom nr2^{n-1}25^r]=2^n(2+3)+($ a multiple of $25)$
$(2)$Modular Arithmetic
$3^3\equiv2\pmod5\implies3^{3n+1}=3(3^3)^n\equiv3\cdot2^n\pmod5$
Answer: First, show that this is true for $n=1$:
$3^{3\cdot1+1}+2^{1+1}=85$
Second, assume that this is true for $n$:
$3^{3n+1}+2^{n+1}=5k$
Third, prove that this is true for $n+1$:
$3^{3(n+1)+1}+2^{(n+1)+1}=$
$3^{3n+4}+2^{n+2}=$
$27(3^{3n+1})+2(2^{n+1})=$
$27(\color{red}{3^{3n+1}+2^{n+1}})-25(2^{n+1})=$
$27(\color{red}{5k})-25(2^{n+1})=$
$5(27k-5(2^{n+1}))$

Please note that the assumption is used only in the part marked red.
Answer: Other users have already outlined the proof by induction, but I think a direct proof is interesting as well.
By Fermat's little theorem (or by inspection), we know that
$$3^4 \equiv 2^4 \equiv 1 \pmod{5}$$
This means that powers of $3$, modulo $5$, are determined by the exponents remainder when divided by $4$.
$$3^{3n+1} \equiv \begin{cases}3 \pmod{5} &\mbox{if }\,\, n \equiv 0 \pmod{4}\\
1 \pmod{5} &\mbox{if }\,\, n \equiv 1 \pmod{4}\\
2 \pmod{5} &\mbox{if }\,\, n \equiv 2 \pmod{4}\\
4 \pmod{5} &\mbox{if }\,\, n \equiv 3 \pmod{4}\\
\end{cases}$$
$$2^{n+1} \equiv \begin{cases}2 \pmod{5} &\mbox{if }\,\, n \equiv 0 \pmod{4}\\
4 \pmod{5} &\mbox{if }\,\, n \equiv 1 \pmod{4}\\
3 \pmod{5} &\mbox{if }\,\, n \equiv 2 \pmod{4}\\
1 \pmod{5} &\mbox{if }\,\, n \equiv 3 \pmod{4}\\
\end{cases}$$
For each possible residue for $n$ modulo $4$, the sum is $0$ modulo $5$.
Answer: Divisibility by $5$ is unaffected if we multiply the given expression by $9=3^2$. So let's consider
$$
3^{3n+3}+9\times2^{n+1}\equiv(3^3)^{n+1}-2^{n+1}=27^{n+1}-2^{n+1}\equiv 2^{n+1}-2^{n+1}=0\pmod{5}.
$$
Answer: Note $\ 3\cdot 27^n + 2\cdot 2^n  = 3(27^n-2^n) + 5\cdot 2^n\,$ so it suffices to prove $\,5\mid 27^n-2^n.\,$
Below are few ways, using conceptual lemmas, all which have easy (inductive) proofs.
$(1)\ \  \ a-b\mid a^n-b^n\,$ so $\,25\mid 27^n-2^n.\,$
$(2)\ \ \ (2+25)^n-2^n = 25k\,$ for $\,k\in \Bbb Z\,$ by the Binomial Theorem.
$(2)\ \ \ {\rm mod}\ 5\!:\ 27\equiv 2\,\Rightarrow\, 27^n\equiv 2^n\,$ so $\,3\cdot 27^n+2\cdot 2^n\equiv 5\cdot 2^n\equiv 0.\,$  by  Congruence Rules. Most of the other proofs are essentially the same as this, but without the congruence language. See here where I explain how such proofs essentially unwind a proof of the Congruence Product Rule.
Answer: Note that the expression is $x_n=3\cdot 27^n+2\cdot 2^n$.
It is a fact that any $y_n=A\cdot a^n+B\cdot b^n$ satisfies the recurrence relation (which can be verified by direct computation) $$y_{n+2}=(a+b)\cdot y_{n+1}-ab\cdot y_n$$
From this we deduce that if $p\mid y_n$ and $p\mid y_{n+1}$ then $p\mid y_{n+2}$ This explains why divisibility, once established for two consecutive elements, persists for all elements in a wide range of these expressions, which often crop up as examples.
Here $x_{n+2}=29x_{n+1}-54x_n$
This method uses two base cases, of course, so isn't pure induction - but it explains what it is that makes the induction work.