Clapping during Amidah

Question: I've seen (and heard) on occasion people clapping during Amidah, and I've always wondered why. Personally, I find it annoying, so I was wondering if there was some source that explained the reasoning behind this.
Comment: R. Reuven Ohana wrote a scathing attack on this practice in the journal Ohr Torah (Siwan 5754, siman 98, pp. 682-686).  The essay is titled בעניו מחיאות כפים בשעת התפלה.
Comment: During chazaras hashatz, or shemona esrei itself?
Comment: @KovyJacob itself. I've never seen anyone clapping during the chazarah unless there was singing, and not allowing that I think is a גזרה שאין הציבור יכול לעמוד בפניה...
Comment: @Harel13 I haven't, either... I ask because first of all clapping during shemonah esrei sounds absurd, and also, I've never seen it.
Answer: Rabbi Nachman of Breslov had a personal belief in the power of clapping, and put this information in Likutay Moharan. Those who count themselves among his students clap to tap into this power to this day. Here is some information about why they believe this.
It is worth adding that Eruvin 65A forbids distracting others during tefillah, and this is brought in the Shulchan Aruch as the halacha.
Comment: I can confirm the answer. It's a terribly annoying practice.
Comment: @Kazibácsi It's annoying and I find the practice to be chutzpadik, drawing unnecessary attention to yourself while davening, as if to say "look at me davening with so much fervor".
Comment: Tefila and shemonah esrei are different - there are different halachos. Just because Rebbe Nachman talked about clapping during davening, it doesn't necessarily mean (and probably doesn't mean) shemonah esrei. It is very, very shver to be in any minute way distracted during shemona esrei.

Clapping during Amidah


How to identify transfer functions in a time series regression forecasting model?

Question: I am trying to build a time series regression forecasting model for an outcome variable, in dollar amount, in terms of other predictors/input variables and autocorrelated errors.  This kind of model is also called dynamic regression model.  I need to learn how to identify transfer functions for each predictor and would love to hear from you about ways to do just that.
Comment: Let me suggest you the [R time series tutorial](http://www.stat.pitt.edu/stoffer/tsa2/R_time_series_quick_fix.htm). It does not provide deep theoretical knowledge, but it does give you a nice introduction. Also, googling for "r time series" gives you a lot of very interesting links
Answer: The classic approach, described in Box, Jenkins & Reinsell (4th ed, 2008) involves looking at the cross-correlation function and the various auto-correlation functions, and making a lot of subjective decisions about the orders and lags for the various terms. The approach works ok for a single predictor, but is not really suitable for multiple predictors.
An alternative approach, described in Pankratz (1991), involves fitting lagged regressions with AR errors and determining the appropriate rational lag structure from the fitted coefficients (also a relatively subjective process). Then refitting the entire model with the supposed lag structures and extracting the residuals. The order of the ARMA error process is determined from these residuals (using AIC for example). Then the final model is re-estimated. This approach works well for multiple predictors, and is considerably simpler to apply than the classic approach.
I wish I could say there was this neat automated procedure that did it all for you, but I can't. At least not yet.
Comment: Are you working on the automated procedure?  :)
Comment: :Shane ; DONE !
Answer: Originally the idea of examining pre-whitened cross-correlations was suggested by Box and Jenkins. In 1981, Liu and Hanssens published( L.-M. Liu and D.M. Hanssens (1982). "Identification of Multiple-Input Transfer Function Models." Communications in Statistics A 11: 297-314.) a paper that suggested a common filter approach that would effectively deal with multiple inputs whose pre-whitened series exhibit cross-correlative structure. They even created a 2 input model data set to demonstrate their solution.
After we programmed that approach and then compared it to the Box-Jenkins pre-whitening approach iteratively implemented by us we decided to not to use either the Pankratz approach or the Liu-Hanssens approach.We would be glad to share the Liu-Hansens test data with you if you wish me to post it to the list.


Selecting wifi adapter on Windows 7

Question: I have two wireless networks at home, 2.4 GHz and 5 GHz. Since my network connection is very fast, I prefer to use the 5 GHz one. However, I have a built in wireless adapter which is 2.4 GHz and a USB dongle which is 5 GHz. For some reason Windows insists on using the 2.4 GHz adapter to connect to wifi and I cannot get it to display the networks from the 5 GHz adapter in the list. I tried to change the metric in the advanced settings of the adapters but that didn't help. How can I tell Windows that I want it to use Wireless Network Adapter 2?
Comment: Disable the onboard adapter?
Comment: Tried that. It disables all WiFi adapters at the same time when you click disable.
Comment: That shouldn't happen, how are you disabling it?  Normally you'd disable a device via the Device Manager...
Comment: Ah, I went to the device in networking settings, right click then click disable. I guess I should have done it in device manager.
Answer: Metric won't help you as it prioritizes established connections. Quick and dirty fix (if you usually don't need your built in adapter): Disable the adapter altogether.

Selecting wifi adapter on Windows 7


Gradient theorem in line integrals

Question: For the line integral
$$\int_{C} \left( \frac{dx}{x} + z^2 dy + 2yz dz \right)$$ where $C$ is the path of the line segment from $(1,0,0)$ to $(1,2,1)$ followed by the line segment from $(1,2,1)$ to $(2,1,4)$.
Can I employ the gradient theorem here? Is it safe to say that the vector field $\mathbf{f}$ is conservative? I found that the curl of the vector field is zero, BUT there's a singularity at $x=0$. However, the path never passes through that $x=0$, so is this okay?
Answer: Yes - the vector field is conservative.
The integrand is  $\vec {\nabla} f \cdot d \vec r$
where $f$ is the scalar field given by
$$f(x,y,z)=\ln x + yz^2$$
The value of the integral depends only on the endpoints of your path.
Comment: Thanks. I think my query is mostly based on the other question - in the other comment on this thread
Answer: Well you can definitely write
$$ \int_{C} \left( \frac{dx}{x} + z^2 dy + 2yz dz \right) = \int_{C} \nabla (\ln(x) + yz^2)\cdot(dx,dy,dz).  $$
Then the gradient theorem implies that line integrals through gradient fields are path independent. See Gradient theorem wiki for more on this.
To answer your question in the comment below. Every conservative field can be written as the gradient of a scalar field. This is what I have done above.
So what we have done is written a conservative vector field $\mathbf{V}(r)$ as the gradient of some scalar field $\nabla S(r)$ i.e.
$$ \mathbf{V}(r) = \nabla S(r). $$
Now, we are free to take the curl of the above i.e.
$$ \nabla \times \mathbf{V}(r) = \nabla \times \nabla S(r) = 0. $$
In vector calculus the curl of a gradient is zero. Hence, the curl of a conservative vector field  $\mathbf{V}(r)$ is always zero!
Comment: How would we determine that it is conservative via looking at its curl and region? I recall that if the curl is zero AND the region (domain?) is simply connected, it is conservative. Why is this region simply connected?
Comment: @PaulWoch I've edited my answer to address why the curl of a conservative vector field is always zero.

Gradient theorem in line integrals


I left fully cooked lasagna out all night

Question: I left fully cooked lasagna out on the counter all night. My house is 72 degrees Fahrenheit (22 degrees Celsius). Is it safe to reheat and eat?
Comment: There is insufficient information in the question for anyone to give a definitive answer. For example, how was the dish covered? was is in a container or open for flies and cockroaches to crawl over while you slept.
Comment: Aaronut has written some excellent food safety answers, such as http://cooking.stackexchange.com/questions/16665/is-it-really-necessary-to-wash-a-skillet-that-will-be-heated-up-again-soon/16672#16672 and http://cooking.stackexchange.com/questions/12992/why-is-it-dangerous-to-eat-meat-which-has-been-left-out-and-then-cooked/13009#13009 - have a look at those, before you even think about trusting the more "adventurous" (i.e. potentially dangerous) answers here.
Comment: There are a lot of similar questions out there. The fact you post it means you know, deep down, that it's not safe.
Comment: I don't have any professional experience so just anecdotal and your mileage may vary: I have done so many times, with lasagne and spaghetti bolognese etc. also where it wasn't covered by any means. I have never been sick. Also, I know plenty of people (including my parents) who will always leave what remains of pizza, lasagne etc. in the oven for the next day so it is just a matter of turning on the oven to heat it up. Seems this is just how they were brought up, and has never caused problems. I will usually put in the refrigerator unless I forgot. But I do, I will eat it anywyay.
Answer: Throw this out. The general rule of thumb is that food that isn't otherwise preserved (through  large quantities of acid or sugar for example) must not be in the danger zone from 40-140 degrees Fahrenheit for more than 2 hours. In practice this is an oversimplification - see the incredible and incredibly detailed food safety section in Modernist Cuisine for the whole story. Overnight is way too long. It is quite possible for bacteria to have multiplied and secreted toxins which are heat stable. E. Coli and Staph. Aureus both do this, for example. Reheating will not make this safe. It isn't worth making yourself or your family horribly ill. Order pizza.
Comment: It doesn't take "a bunch". *One* cell of these microorganisms, if allowed to thrive in a warm, moist environment for 12 hours could grown into billions of them. Unless of course your house is a surgical operating theater and your tomato sauce contains bleach.
Comment: @Satanicpuppy: Yes, exactly, they USDA and other agencies post guidelines that minimize risk. That is exactly what they do, and that is exactly what we need to do when answering food safety questions. It is the **only** responsible thing to do. We can certainly go into more detail and attempt to quantify the risk and let people make their own decisions if they wish to ignore the dangers, but simply telling people to ignore the guidelines because *you* think it's safe is extremely irresponsible and inappropriate. By all means add a caveat to the accepted guidelines but don't ignore them.
Comment: @Peter, this isn't an issue of agree or disagree, it's one of fact. There are at least a dozen common household bacteria that thrive in warm, moist environments and produce toxins within 2 hours. 4 hours is the absolute maximum time you can leave hot or warm food out and still be safe. Doesn't matter if it's cooked or not. Obviously the danger is greater with raw meat, but that's only because raw meat has a greater likelihood of being contaminated in the first place.
Comment: @Satanicpuppy: Please, tone it down with your food safety rants. Unless you're an expert on microbiology, you have no basis from which to make such broad, sweeping claims. The fact is, tomato sauce does not have a high enough pH to stop bacterial growth, home kitchens are not sterile environments, and the type of cheese used in lasagna (mozzarella, ricotta, etc.) is more than moist enough to support bacteria, especially after being drenched in tomato sauce and water from the cooked pasta.
Comment: @michael: With a double rate of about 20 minutes, you'd need 10 hours just to get *one* billion, assuming the contamination was instant, the food was in the dangerzone, and also that the food was an ideal growth medium. In practice, you're more likely to get the e coli poisoning from your side salad. I'd put it at higher risk than raw eggs, but at a lower risk than raw chicken.
Comment: @michael I strongly disagree with your perspective here. Staph will not be present unless someone sneezed on the lasagna post-cooking.

E coli will have been killed during initial cooking, and will therefore have already released all the toxins they can.  If it was safe the first time, and not sneezed on or re-infected with E-coli, it will continue to be safe if reheated.
Comment: Well let's take one obvious way it could be contaminated. Presumably it got wrapped with tin foil. Were the hands of the person who handled that tin foil absolutely sterile? Not likely. It is perfectly possible for a few germs to be present on those hands, which get transferred to the foil or plastic, and from there into the food where it will find an inviting warm, wet environment in which to multiply. This isn't just an opinion, it is the law for food handlers everywhere.
Comment: @Peter: It's fine if you would eat it. Really, it is. But the question doesn't ask, *would you eat it?* It asks, *is it safe to eat?* Those are two different questions.
Comment: Well, if my lasagna had a bunch of living *staph* or *e coli* in it after I'd cooked it, I'd think there were bigger problems than it sitting out for a while. There are more sensible bacteria to be concerned about in cooked food, at home.
Comment: +1 Completely agree here.  Your kitchen isn't a sterile environment - well a *normal* person's kitchen.  Its not like any lasagna is worth a potential trip to the hospital.  Odds are you'd be fine, but how stupid would you feel telling the doctor at the ER that you ate the food sitting out all night and thats why you're there.  If in doubt, throw it out.
Comment: @michael: It'll find a layer of cheese, which is a crappy growth medium (it's dry, and it's the byproduct of a ton of intensive bacterial growth, which means less food for newcomers). And then a layer of tomato sauce, which is a crappy growth medium (it's acidic and salty). And no, I wouldn't serve it in a restaurant. Restaurants are like hospitals: you'll find more germs there than any other sort of kitchen, and more potential cross contamination. They are held to a high standard for a reason. In a home environment? The risk is much lower. It's not nil, but I wouldn't worry about eating it.
Comment: @michael: This is the same USDA that thinks I need to cook my thanksgiving turkey to 165F, right? They make recommendations for being as close to 100% safe as possible. Overnight lasagna ain't it. Nor a hamburger with pink in it, or a pork loin with juice in it, and you can throw your steak tartare out the fricking window, because that is like the worst thing imaginable from their point of view...Or you can accept that sometimes its worth not being 100% safe.
Comment: @satanicpuppy - you are right that some of the USDA advice is overkill (and actually, it turns out some of it is underkill - Nathan Myrhvold spent some time with them trying to get them to update some regs based on the research for Modernist Cuisine). However, the degree to which they overprotect is relatively small. If doublings are every 20 minutes, the difference between 2 hours and 14 hours is 2^36 bacteria - about a factor of 68 billion times the original count. Not close. Just because they are a little overprotective in some cases doesn't mean you should throw out basic research.
Comment: @aaronut: And I didn't add caveats, where? The bias here is so far the other direction that any statement of the form "this probably won't kill you" is viewed as the rankest heresy.
Comment: @Satanicpuppy: Who cares? Death isn't the subject of the question, or of food safety in general; sickness is.
Comment: And let me cite one more source: the USDA Food Safety and Inspection Service: fsis.usda.gov/factsheets/Danger_Zone/index.asp, which is crystal clear on the subject. Two hours in the danger zone, period. Overnight isn't even remotely close to safe.
Comment: @Satanicpuppy: You can't say with authority that "this probably won't make you sick", at least not based on any facts presented so far. The best you can say is that it *might* not, and that's not really a very useful or interesting answer to a question which asks, "can this make me sick?" The chances of a plane crashing or falling out of the sky are similarly low, but they still keep oxygen masks and life preservers on board, because a small risk, taken over millions or billions of trials, turns into a near-certainty.
Comment: I haven't had the pleasure of reading Myhrvold's research, sadly. I will say I agree generally with @satanicpuppy's perspective that I would eat reheated lasagna under the terms described above. I agree with Michael and Aaronut that it would not be suitable for guests and certainly not at a professional food establishment.
Comment: Update, I didn't realize Aaronut and Satanicpuppy are in an extended debate on this site re: food-safety questions. I'll bow out now.
Comment: @aaronut: I said "Kill you" not "Make you sick." And even there I said "Probably."
Answer: Was the pasta in a sealed container? If it was left open to the air or was touched by anything that could contaminate it, it might not be ok.
On the other hand, I have left rice and pasta out overnight in the pot with the lid on at room temperature numerous times and never had a problem. This "two hours at room temperature and throw it out" thing is really overkill almost all the time. Only if you are pretty unlucky will the food be unsafe to eat.
Comment: Food safety is not about being safe most of the time, or safe unless you're unlucky. There are a lot of people out there, and we want them *all* to be safe, not just the lucky ones. If everyone follows your advice, a lot of people will get seriously sick.
Answer: If by reheat you mean get the internal temperature up over 140F for more than 10 minutes (and it won't really taste "hot" until you do so), then it's totally fine, provided that it was fully cooked originally.
That said, if you cooked it fully originally, unless there's something a little funky about your ingredients, you're probably fine to eat it cold right now. Of course "probably" is very different than definitely.
Hence, 140F if you wish to be sure. Alternately, touching 165F would be plenty; don't even have to wait the ten minutes.
Comment: I'm sorry, but this is dangerous, terrible advice. Bacteria can leave toxins that you can't destroy by reheating.
Comment: I have thoroughly reviewed the link you post, and stand by my general advice. Which bacteria listed on that link do you believe are at risk of growing here, (and note, at a rate which will cause significant toxins being left out 12 hours?)

If the lasagna was safe to eat at first (and in this case, it seems to be, since the author has posted this question), there is nothing on that list that poses a health risk if the lasagna has been re-heated the following day.

Food safety is important, but there's no point in spreading fear needlessly.
Comment: @michael: Eh. I think the lasagna would be fine, but I agree that you shouldn't think heating makes you safer.
Comment: See my answer below, and read http://aggie-horticulture.tamu.edu/extension/poison.html if you have further doubt - there are several bacteria which produce toxins that you aren't going to destroy by reheating. This lasagna could make someone really sick.
Comment: So there is lots of evidence that proves that this might be unsafe, but there is no evidence that actually proves that it is. The USDA regs are a ridiculous standard ... they introduce more harm by over-sterilization then they actually fix. If this was cooked properly to start with, and the food smells good, then eat it and stop wasting your money.
Comment: See my comment on your answer. Staph and E-Coli would need to be re-introduced to be a significant risk based on the parameters of the question.
Comment: I've explained in the comments above how easy it would be for them to be reintroduced.
Comment: And let me cite one more source: the USDA Food Safety and Inspection Service: http://www.fsis.usda.gov/factsheets/Danger_Zone/index.asp, which is crystal clear on the subject. Two hours in the danger zone, period. Overnight isn't even remotely close to safe.
Comment: The problem is that there *could* be something funky about the ingredients, or the prep/cooking/storage conditions, and we just wouldn't know. "It'd be fine 99% of the time, with no way to tell if you're the one in a hundred who gets sick" is not really an acceptable answer to a food safety question.


Lighting a 2d city in Grease Pencil using a shader

Question: I'm drawing a 2d city in Grease Pencil. I'm wondering if there is a way to light the city using Shaders? Or should I just use an actual 3d light or lighter-colored brushstrokes to achieve the desired effect? Below are some examples of what I'd like to do.
Comment: Both ways work (light objects VS manually drawn lighting). Is your question about which method to choose ?
Comment: Yes. I'm wondering which method would be more effective.
Comment: Both are effective. It depends on the creative direction you want to take, your skills in each domain, ... I don't think there is a good answer to your question.
Comment: I'm aiming for a Sci-Fi type kind of city in the background of a drawing.
Answer: Your example images show a very specific kind of glowing effect/vaporwave of lighting that is being suggested in what you want to illustrate. In CGI terminology, this lighting effect is called, Bloom. For Blender, there is one and currently only one method to create this effect.
In your grease pencil object, select the strokes/fills that you want to light up in your scene and move them to a new layer.

With this new layer selected, we will convert it into a mesh by going to Object $\rightarrow$ Convert $\rightarrow$ Bezier Curve. Grease Pencil objects can't directly convert into meshes so; we must convert them into curves before we can convert them into meshes. Now we can go to Object $\rightarrow$ Convert $\rightarrow$ Polygon Curve. In Edit mode, fill the mesh curves with faces.

Bloom can only be applied to emission materials. Shader materials are different from Grease Pencil materials. Shaders need to be applied to mesh faces to be shown in our renders. Hence, why we had to duplicate our Grease Pencil strokes/fills into mesh faces.
Next, we need to move our newly generated mesh into a new scene. Make sure you have a new separate scene created by going to the top right corner. Go to Object $\rightarrow$ Link/Transfer Data $\rightarrow$ Link Objects to Scene $\rightarrow$ select your new scene; to move your mesh into the newly created scene. You can delete the mesh from your original scene by unlinking the object and deleting the copy.

Now, we can finally apply the bloom. In your new scene, go to Properties -> Render Settings -> and select Bloom. To create a basic emission material, we can use the shader node or switch to emission in the Materials Properties tab. For my example, I copied my grease pencil material HEX color to paste into my emission color and adjusted the emission strength to $30$.

This option only works with the Eevee rendering engine. To show bloom in cycles, we must use the Glare node in the Compositor workspace. Even though, I just mentioned a different method to create bloom, it doesn't change the fact that we still need the emission material to accomplish this.
In either scene, go into the Compositor workspace. With the Transparent background selected in the properties tab, use an Alpha Over node to place your new scene over your old scene.

The result is as shown. Bloom is considered a post effect within Blender. Likewise, so is Grease Pencil. In case you didn't know, grease pencil always renders first in front of the camera before any other post effect. Hence, why we had to separate the mesh into a new, different scene and, why we needed the compositor to control the order of post effects rendered.

Additionally, in Object Properties -> Visibility -> I unchecked Use Lights for the grease pencil object to control how the grease pencil renders and I did a little more modeling for the mesh then I had previously demonstrated. For any more additional properties that I could have omitted, below is the blend file of my example.

Blender 4.0.2


How do I gain access to files that an Android app stores in its persistent internal storage directory?

Question: I was playing a game that had hidden achievements and wanted to find the conditions necessary to unlock these achievements. To do this, I've tried to get the source code of the game, to find the achievement trigger. The PC version of the game seems to have been written in C++, making the decompiled code near unreadable. So, I got the APK for the android version of the game, and managed to convert the classes.dex file into a jar, which I have now decompiled into readable code. The problem is, there was no code for the classes I was looking for. I don't think any of the code I've seen even relates to the sort of game features I want, having more to do with file and asset management than player control, stat records, NPC behavior, or events. I asked a question about this on a different Stack Exchange site, but have since done a bit more research. It seems that, when the APK is installed onto a device, it requires an internet connection, in order to download all of the other files necessary for the game to run. Is there a way I can gain access to these files? I'm pretty sure that they are in the persistent internal storage directory for this app.
Answer: Best way to access app internal (persistent) storage directory is a rooted device. Once you have root permissions you can access the app internal directory which is located in /data/data/<app packagename>
On an unrooted device you don not have direct access to the app internal (persistent) storage directory.
If the app allows backup (most apps do not) via adb backup <packagename> then you can get indirect access to the app internal storage directory.
Note that Google has limited adb backup on Android 12+: It only works for apps that have a targetSdkVersion of less than 31. App data of app that have targetSdkVersion 31+ are excluded from backup, the backup will stay empty for such apps.

Make sure debugging is enabled on phone and Android SDK/adb is installed on your PC and the phone is connected via USB to the PC
On the connected PC execute adb backup <packagename> this will backup all app data to an encrypted backup.ab file.
If the created backup.ab file has a size of 0 bytes then backup is disallowed for the selected app
If the backup.ab file has a size greater 0 you should be able to decrypt and convert it to to a TAR archive using Android Backup Extractor (abe)
Extract the created tar file and you should have all data stored by the app in it's internal storage.
Comment: Thank you for the help. I tried doing as you suggested, and the resulting app data on the extracted tar file did not have all of the data that I wanted. To put this into perspective, the app on my phone takes up more than 800 MB of space. The data for the app stored within the extracted tar file take up less than 60 MB of space. Will I just have to root the device? And is it possible to do the rooting on some sort of emulated device, in order to get the files I want?
Comment: Okay, so I got a rooted emulator with the app on it, and managed to dig through the files  until I found a .OBB file that had everything I wanted in it. That was pretty good, but the thing is filled with generic garbled file and resource data. My plan is to take these files tomorrow and find some way to decompile, or decrypt, or whatever, them into something useful. How I'm going to do that is pretty hazy, so if anyone sees this and has suggestions, I'm open.
Comment: @Micheal Your question was only about the data files crated by the app. OBB files are AFAIK not downloaded/created by the app but from Google Play Store/Play Services. If you just want the app code it is usually easier to check web sites like apkpure.com or apkmirror.com - often they have the complete app package available for download.


GDB exited when running library

Question: I'm new with gdb and I have spent hours looking for direction but I can't find any.
I need to analyze an executable to find how this program process the arguments and where the output came from. I have it running on my system, got it working correctly to print some encoded string.
After some days trying gdb, I figure that I need to trace the data inside every function, but I can't pass this function __libc_init where the program alwas exited with code 0235. The last process says __libc_init () from /system/lib/libc.so
so i think it's doing something with this external library libc.so. How could I continue the debug process when I hit this type of process? I can't find any reference to understand this.
Answer: If you cannot step inside that function, you're probably missing debug symbols for the library (check with info shared). You can try to either install symbols (usually in a package named libc-dbg or similar), or debug on assembly level by using si (step instruction) command.
Comment: this is new for me, i thought that the external library debug symbol not required in this process. for the code itself, i have make sure that the debug symbol is available. i think i'm not interested with the external library's process, so i want to skip to when this library call is finish, and check for output and other values. is it possible?
Comment: If you want to know why it's exiting in that function, you'll have to go inside.
Comment: ooh so that's how it is. i think gdb is too advanced for now. gonna try analyze the strace and objdump output now before going back here and try your advice. thankyou!

GDB exited when running library


Deleted CA Certificates in Firefox

Question: I was very silly and deleted all my default CA certificates in Firefox. (I'm using Ubuntu). How do I get them all back?
Comment: Hello!hysically deleted? Or from Firefox-User-Storage/configuration System (means as url: about:config)? Which Filesystem do you use?
Answer: You can create a new a new temporary profile and then copy the cert8.db file from the new profile.
To create a new profile you may need to start firefox with:

firefox -ProfileManager

and then click "Create profile". Then start firefox once with the new profile to have it create the profile's files.
After that exit firefox and then copy ~/.mozilla/firefox/[new profile directory]/cert8.db to ~/.mozilla/firefox/[old profile directory]/cert8.db. The profile directories' names end with the name of the profile, so that's how you can know which is the new one and which is the old one.
Finally switch to your old profile (you may need to start with the -ProfileManager option again) and you should have the default CA configuration.
Answer: I had a similar problem, so I made a script to recreate the certificates only with pages I like, or dislike, but have to use, as say google:
address=www.google.com
firefox $(openssl s_client -showcerts -connect $address:443 </dev/null 2>/dev/null|openssl x509 -in - -text |grep ".crt" | sed -e 's/.*URI:\(.*\)\n*/\1/')

or
address=www.google.com
firefox $(openssl s_client -connect $address:443 2>&1 < /dev/null | sed -n '/-----BEGIN/,/-----END/p' | openssl x509 -in - -text | grep ".crt" | sed -e 's/.*URI:\(.*\)\n*/\1/')

and reload original page.
Or in a more elaborate bash script:
#!/bin/bash
if [ -n "$1" ]; then
  address=$1
else
  address=$(whiptail --inputbox "Enter a URL of the page with an unknown issuer (without https://):" 8 78  --title "Add a new certificate into Firefox" 3>&1 1>&2 2>&3)
fi
crt=$(openssl s_client -showcerts -connect $address:443 </dev/null 2>/dev/null|openssl x509 -in - -text |grep ".crt" | sed -e 's/.*URI:\(.*\)\n*/\1/')
echo "Attempt 1: $crt"
if [ -z "$crt"  ];then
crt=$(openssl s_client -connect $address:443 2>&1 < /dev/null | sed -n '/-----BEGIN/,/-----END/p' | openssl x509 -in - -text | grep ".crt" | sed -e 's/.*URI:\(.*\)\n*/\1/')
echo "Attempt 2 (from crl): $crt"
fi
if [ -n "$crt" ];then
    firefox $crt
    exit
else
    echo No success in finding of crt file.
fi

The main task is to extract from URL (say https://www.google.com) so called "Authority Information Access" where there is exact URL of crt file, which can be imported into Firefox. This is the easiest way which I have found.
The GUI way how to do the same:

firefox/preferences/privacy&security/ViewCertificates/CertificatesManager/Servers/addExeption
Write the URL into the location: https://www.google.com
Then click: GetCertificate
Button: View/Details/AuthorityInformationAccess/
There are the URL of certificate in the Field value:
CA Issuers: URI: http://pki.goog/gsr2/GTSGIAG3.crt
OCSP: URI: http://ocsp.pki.goog/GTSGIAG3
Copy the address crt file: http://pki.goog/gsr2/GTSGIAG3.crt
and open it in firefox window
reload original URL
I do not why, but sometimes firefox imports a crt file and sometimes it just downloads. So I have to import it via this GUI method.

Well, the script is faster, but 8 hours of my life, so I hope it will simplify your life... :-)

Deleted CA Certificates in Firefox


Is being a morning person vs a night person actually a real thing or just a preference?

Question: Are there real physical differences between a morning person vs a night person that can be measured and used to explain the difference?
Or is it just an adapted preference randomly varying from person to person?
Answer: (see also this Q&A over at Biology.SE: https://biology.stackexchange.com/questions/93965/why-do-morning-people-have-shorter-biological-clocks/93966)
It's a real thing, but that doesn't necessarily mean it's set in stone or that preferences can't be changed/learned.
At least some portion of these preferences seem to be genetic and related to regulation of circadian rhythms. In brief: animals, including humans, have a system of molecular "clocks" that keep track of roughly the length of a day. These clocks most often run naturally slightly longer than 24 hours: if you keep someone (or, preferably, a lab animal) in constant darkness, they will still keep a daily sleep/wake cycle, but it will drift over time, corresponding to a >24 hour day.
To actually follow the real cycle of day and night, light is used to resynchronize the clock every day.
If someone's "natural" clock (without light synchronization) runs a bit shorter (faster) than average, you'd expect that person would tend to feel like waking up a bit earlier as well as feeling tired a bit earlier in the evening - a morning person. If someone's natural clock runs a bit slower than an actual day, then morning will come a bit sooner than they prefer, and in the evening they won't quite feel tired yet.
That said, like most traits of this nature, the biological underpinnings of these tendencies only explain part of it, and you would not expect to find people sorted neatly into "morning" and "night" but rather to follow something like a Gaussian distribution, with most people in the middle.
Here's a recent genome-wide association study and a review of some others on "chronotype" (the morning/night preference you ask about):
Jones, S. E., Lane, J. M., Wood, A. R., van Hees, V. T., Tyrrell, J., Beaumont, R. N., ... & Weedon, M. N. (2019). Genome-wide association analyses of chronotype in 697,828 individuals provides insights into circadian rhythms. Nature communications, 10(1), 1-11.
Kalmbach, D. A., Schneider, L. D., Cheung, J., Bertrand, S. J., Kariharan, T., Pack, A. I., & Gehrman, P. R. (2017). Genetic basis of chronotype in humans: insights from three landmark GWAS. Sleep, 40(2).


How to train a keras model on both original and augmented data from ImageDataGenerator?

Question: I have a dataset that contains about 87000 images in a directory, with each class in a separate subfolder. I've tried the class ImageDataGenerator() and the function flow_from_directory() for generating the images, it worked completely fine but I have a question..
Does flow_from_directory() only yield the augmented images? and if this is the case, how can I train my model "which has overfit the training set" on both original and augmented data?
Thanks
Answer: ImageDataGenerator do augmentation on the fly base on the setting you give , so it did not separate "original" or "augmented " data , just the possibility of data been augmented.
so your question actually is " how to tune model when overfitting happens "? I think you can start from adding dropout or reduce number of parameters. Hope this helps, cheers.
Comment: I've tried adding dropout and parameter reduction, they helped by increasing validation accuracy from 0.72 to 0.85, but I think there's still a room for improvement. Thanks!
Answer: Below are the things can be done in order to reduce variance (overfitting):

Add more training data.
Normalization (BatchNorm, LayerNorm)
Data Augmentation
Regularization (Dropout, L2, WeightDecay)
Error Analysis
Tune Hyperparameters
Early Stopping
Use better state of the art model or transfer learning


How is rooting done under the hood?

Question: I recently rooted my device which got me curious regarding the process. I would really like to understand how rooting applications work under the hood. Articles I have found over the internet have been very vague. I really would like to root my device all by myself. How can I get started with the same? Id really appreciate some guidance and/or pointers.
Comment: Have you done any research on say http://forum.xda-developers.com/ that would probably be your best bet. Or even http://freaktab.com/ they have some really nice people willing to help out and point better direction.
Comment: Please read the android tag.
Answer: Basically, it involves exploiting some vulnerabilities(for example, a buffer overflow) in Linux kernel to gain advanced privileges. The exact technique used varies with devices and Android versions. This Stackoverflow answer should give some idea. Androidcentral has a page that gives more information on root.

How is rooting done under the hood?


"Think of" versus "think about"

Question: Could someone help me to understand when I should use think of and when think about in sentences?
What is the difference between using one or the other?
Answer: I'm trying to think of a context where there is a difference, and it's very hard to do that. What makes this tricky is that the two are pretty much interchangeable in many contexts:

When I think about/think of my mother, who passed away three years ago, I get very sad.

but there are other occasions when one would be slightly (or clearly) favored over the other:

I get excited when I think about football season getting underway.
I can think of 10 reasons why you shouldn't text and drive.

And then there's this gem:

I can't think of it right now, but maybe I will, if I think about it long enough.

If I had to summarize, I'd say that think of seems to mean recalling something specific, while think about seems to mean considering some subject in a more vague or general way for some length of time. The two are sometimes interchangable because there are many situations where you can't think about something without also thinking of it, such as when you are fondly remembering your deceased mother.

This is a great question; I hope others weigh in. I think I might be getting close to something here, but I'm not convinced I've nailed it.
Comment: Of course the other meaning to *think of* is the inventive case.  *I just thought of this a new product we could sell.*
Comment: I think you are right on. *Think of* is simply the act of recalling to mind.  *Think about* means to ponder or consider. Lots of times though, one will think *of* something and then think *about* that same thing.  Much like web surfing in your mind...
Comment: Noting your initial point about it being hard to find contexts where the preposition makes a difference, I've just copied across my ELU answer to the same question. I assume that doesn't count as undesirable "cross-posting"!
Answer: Adding to the answer above, "think of" is often used when we wish to express an opinion of someone...

either without actually doing so:

I can't tell you what I think of you.

or with an adverb in-between:

I think badly of him.
  I think well of him.

We would not say "I think badly about him" — that would mean that when we think about him we don't think well!
Answer: As a language teacher, this is something my students ask me a lot. So, I have researched this topic the best way I could, which is by using Corpora (an analysis of millions of texts in English). I did this in order to give the best answer I possibly could, because being a native speaker was not enough to put everything in order. Here's what I found.
Compared to the previous posters, some of what is said is true and other is not. So both of these are actually equally frequent in their use, around 80,000. Mostly, these have very different meanings, except one case, which is giving an opinion (see below). The frequency of this use case, however, is not so high ("what do you think about/of"+"what you think about/of" is 4-5% of total use cases.
Summary:
Think of (Meaning: bring something into your mind)
Use cases:
•   New ideas
•   Reminder of people or things
•   Brainstorming
•   Finding solutions
•   Giving an opinion (About 5% of total use cases)
Think about (Meaning: concentrate and focus on something)
Use cases:
•   Concentrating on a topic, person or action
•   Taking a person into consideration
•   Memories and experiences
•   Giving an opinion (About 4% of total use cases)
Examples of common phrasing:
"Think of someone who helped you." = Search through your memories.
"California is an agricultural state and so many people don't even think of it that way." = Consider something as something, an opinion.
"And that's a funny thing, when you come to think of it." – when it enters your mind.
"What do you think of her?" = Invitation to give an opinion
"Think about it. It's a great idea." = Give it consideration and contemplation.
"I want you to think about your daughter who loves you before you make this decision." = Keep her in consideration.
"You're not a kid anymore. You have to think about your future, Jess." = Keep it in consideration.
"What do you think about that?" = Invitation to give an opinion
The chosen answer in this case gives this example of equal meaning: "When I think about/think of my mother, who passed away three years ago, I get very sad."
These sentences have the potential to be equal in meaning but only when combined in this way. Here's the difference:
"When I think of my mother..." = When I am reminded of my mother. In this case, just the though makes me sad. For example, seeing a picture or her favourite TV show, could make make me think of her, and that makes me sad.
"When I think about my mother..." = When I concentrate on and contemplate her. In this case, the contemplation and concentration on the topic makes me sad. Just being reminded of her doesn't affect me so much, but really concentrating on the topic does. Just seeing her picture or just seeing her favourite things, wouldn't make me sad. But when I sit and think about her and the time we spent together, it does.
Be careful when analyzing sentences outside their context to determine meaning. The meaning although close, is not the same and clearly implies or requires a different context.
Conclusion
In the majority of cases, (95%) these two have different meaning. It is only when giving opinions that they can be used interchangeably. In some cases, it is easy to see the difference and in some specific situations, if you ignore the context, it is not so easy. Have a look at the summary and the examples in order to see when one should be used versus the other.
For more information have a look at https://www.english-corpora.org/coca/
Answer: I'm teaching English in a Senior School as a second language.
With the above examples in mind -
    -When I say what I think of Raul - I'm meaning that I'll say my opinion in general, about him... not in detail, but
    -If I say what I think about Raul - I'm meaning that I'll tell some important details I know about him.
Answer: [I've just copied this answer in its entirety from my original ELU answer.]
In many contexts, think of and think about are effectively interchangeable...

"They say Greece may leave the Eurozone. What do you think of/about that?"
"I'm thinking of/about looking for a new job"

In other contexts, to think of something means you're at least aware of the thing, but may not have given it a great deal of consideration. If you think about something this normally implies more focussed or extended attention.

"I never thought of doing that!" (that possibility never crossed my mind).
"Have you thought about my birthday present?" (have you considered/decided what to get me?)

Much the same distinction applies to hear of/about. You might say you've heard of something meaning no more than that you're aware "something" exists. But if you've heard about something the implication is you've heard some important/current information about that thing.

"I've heard of Amy Winehouse" (the name is known to me, but I don't necessarily know any more).
"I've heard about Amy Winehouse" (strongly implies knowing of her untimely death).

"Think of" versus "think about"


can you "voice to text" without using wifi or data

Question: Is there a way or app that allows  "voice to text" when I am not near wifi or have data?
Answer: For the most part, sure.
I just put my Galaxy Nexus (Android 4.2.2) into Airplane mode and tried to compose an email message with speech-to-text.
It worked, but it was slo-o-o-o-w. And not as accurate as I'd like.
If you go into Settings > Language & input > Google voice typing (settings) you can set which languages are downloaded to your device for speech-to-text. English is my default (and is already downloaded) but I see about 20 other files I can download.
However, whether you can do this or how well it works depends a lot (I think) on your device and the version of the OS you're running.
Comment: Any information on the privacy policy when using this offline? IS the data transmitted later when going online?
Comment: It really does depend as I put my phone into airplane mode and it was very fast at picking up my speech and very accurate.
Comment: "I think it depends..." is not an answer.


Meson color wave function

Question: Is the meson color wave function symmetric of anti-symmetric? I know that in the case of the baryon it is anti-symmetric; however, I also know that baryons(which are made of three quarks) are fermions while mesons (which are composed of quark and antiquark) are bosons. Thanks.
Answer: Mesons have valence quark content $q \bar q$ which does not comprise an identical pair of particles so indeed they are not susceptible to Fermi Dirac statistics but rather to Bose Einstein statistics. There is therefore no enforcement of antisymmetry upon the wavefunction description of the bound state.  However, as an observable hadronic state, it must be a colour singlet and so for a quark $q_i$ and an antiquark $\bar q_j$, where $i$ and $j$ label the colour degree of freedoms, we must contract with the Kronecker delta $\delta_{ij}$ to project out the physically realisable configurations. That is to say, the colour component of the meson wavefunction will always be in the $SU(3)$ colour symmetric state $\frac{1}{\sqrt{3}}(r \bar r + b \bar b + g \bar g)$ as $$|\Psi \rangle = \frac{1}{\sqrt{6}}\sum_{i,j} \delta_{ij} q_i \bar q_j$$ entails. The relevant projector in colour space is the $\delta_{ij}$ which is manifestly symmetric.

Meson color wave function


How do you distinguish between "remember" and "remind"?

Question: I used Google to translate "remember" and "remind". Both came out to be recordar. Why is there no distinction made? You can only remember something by yourself, but you have to remind someone else of something. How can recordar represent two different actions?
Comment: Usually the verb `hacer` ("Recordé que tengo que devolver el libro" vs "La tarjeta de la biblioteca me hizo recordar que tengo que devolver el libro") makes the difference.
Comment: Related and beautiful http://www.youtube.com/watch?v=cLbgNvjyS4I
Answer: Recordar (and incidentally acordar) in Spanish works more like recall in English, than like remember or remind.  In English, recall can be used in both senses as recordar, and context determines the meaning:

I don't remember his name / I don't recall his name. → No recuerdo su nombre.
Remind me of his name / Recall to me his name. → Recuérdeme su nombre.

In both cases, the words recordar and recall are more about the act of pulling something from memory (similar to remember), than the act of communication (as in remind).  In the case of recalling to someone, it's the "to someone" part that implies the communication, not the verb itself.

EDIT Remember in English can also work this way, although it's rather rare, archaic or used for artistic purposes.  Consider the traditional English ballad made famous by Simon & Garfunkel as Parsley, Sage, Rosemary and Thyme:

Are you going to Scarborough Fair?
  Parsley, sage, rosemary, and thyme
Remember me to one who lives there
  She once was a true love of mine
Comment: In short, _Recordar_ is a polysemic word that means both _To Remember_ and _To remind_.
Comment: @deStrangis And also "to wake up" (en muchos lugares)
Comment: @belisarius "Recuerde el alma dormida..."
Answer: When Spanish people learn English we have the same problem, why do you use two verbs ? For us recordar is used in both cases.
Recordar means  Traer a la memoria algo.
Whether you want to share it with someone or not is up to you, because before reminding somebody to do something, you have to remember it ;).


Battery imbalance - two 12v lead-acid 100ah in series

Question: I have just installed two brand new 12v lead-acid batteries in series to for my 24v "house system" on my boat. I connected them to my 24v charger to ensure they were charged to 100%, to synchronise my battery monitor. However, the voltages of the two batteries whilst on charge was markedly different: batt 1 15.1v, batt 2 13.8v.
This immediately triggered an imbalance alarm from the battery monitor (mid-point voltage difference). After about half an hour the charger entered its float stage, and the voltages were then: batt 1 14.1v, batt 2 13.4v.
Do I have a problem, or is this behaviour perfectly normal? And if this is normal, how much of an imbalance should I accept?
Comment: Normally you want them balanced << 1% because the 0 to 100% is only 1V and overcharge will boil the acid out of the cell if sustained.  Do you have an active balancer? I would expect 14.5V max 14.2V nom.
Comment: Assuming these are not AGM
Comment: I would contact whomever sold you these batteries.  THere may be some special pre-conditioning charge that you have to do.   I could see if possibly, these two batteries didn't START at the same charge level (i.e. one was more drained than the other).   Charging in series would not fix that.   Maybe you need to fully charge each individually with a 12V charger first so they have a common starting point???   Assume these are "identical" batteries to begin with, right???
Comment: Balance them and try again.
Comment: I second BrianDrummond and KyleB. Fully charge each of them separately, then connect them together again and see how they behave.
Comment: Thanks for the feedback. I'll try charging them individually first, and see how I get on. They are identical lead-acid batteries.
Answer: Yes, you do have a problem.
Series-connected batteries should be balanced, otherwise you always overcharge one of them and over-discharge the other. Neither is good for the battery life and you also get less cycle capacity.
Ways to solve it:

A balancing device. A search for "24v battery equalizer" will get you some ideas.
Charge the batteries in parallel (once, before connecting them in series). The batteries may gradually disbalance over time, but the process is slow and generally negligible for sane batteries.
Use "Balancing charge". In essence, it is a mild overcharge that gets every cell charged to the max while overcharging the already charged ones. Rather harsh and makes batteries to lose some water, but does the job. It also equalizes the cells within the battery. Some controllers do this once in a while, some batteries don't like it very much.

The normal imbalance for a 12v lead batteries is less than 0.5v when charged and way less (less than 0.1v) in intermediate state of charge
p.s. I expect brand-new lead batteries to be of equal (near-100%) state of charge.
Getting two unbalanced batteries means something is not absolutely OK. Either one of the batteries has higher self-discharge, or the batteries are from different batches and were stored for different amount of time.
Comment: Note that equalising and balancing are not the same thing, although they are related! "Equalising" has a specific meaning that applies even to the cells within a single battery, that of a deliberate overcharge to remove sulphate crystals, which shorten the life of the battery. See https://batteryuniversity.com/article/bu-404-what-is-equalizing-charge
Answer: This is normal, and is a result of state of charge imbalance, when the battery reaches above 13.8V it starts splitting the water into hydrogen and oxygen which bleeds off power allowing the other battery to charge. How much imbalance should you accept is a difficult question because no-one really knows about imbalance in lead acid batteries, but it should be okay as long as it doesn't consistently have large imbalances where one battery is over 15V for very long periods.


How to reduce landscape curvature?

Question: My camera is a Nikon D610 which I used with a Sigma 12-24 wide angle lens. Can anyone recommend a software product to straighten up horizons with? I have attached an example where I have a curved lake horizon in my photograph but I don't want to destroy the sharpness of the image.
Comment: There's no way to stretch things in post without giving up at least a bit of resolution. Just ask [Uncle Roger](https://www.lensrentals.com/blog/2013/01/you-can-correct-it-in-post-but/)
Answer: I have not used the latest version, but DxO makes a database of a combination of body and lenses to correct some problems, like chromatic aberration, etc.
They also have a program to correct wide angle lenses deformations: https://www.dxo.com/dxo-viewpoint/
It has a 30-day trial.

Here is another program. A plug in for Photoshop.
http://richardrosenman.com/shop/lens-corrector-pro/

You can also use Photoshop.

Paint shop pro has some basic corrections too.

Affinity Photo has some automatic lens corrections.

And you also have Hugin (This program does so many things)

But yes, you will sacrifice some of the image data. With extreme corrections, you need to crop the image, all the stuff that does not fit in the new rectangle.
In the specific case of your image, you will be fine.
Comment: Thank you Rafael. You have given me much to study. Looks like Hugin will be a worth a good look as well as lens correction for the specific lens. Cheers!
Answer: It's a lake.  It does not have a horizon on this picture (which would be a transition of water to heaven or at least of water to non-water adjacent landscape) as much as it has a shoreline.  The shoreline is curved.
Of course you may want to straighten the lines for artistic reasons rather than geometric ones.  You will sacrifice some subpixel amount of sharpness: that's not avoidable.  To make this not unnecessarily accumulative on top of other camera-internal geometric processing losses, you'll be best served starting with the RAW image and doing all geometric processing in one swoop.  A number of raw processing programs can do geometric correction of both camera and lens starting from profiled parameters, but if you want to straighten a shoreline, the profiled parameters will not be sufficient.
Comment: Thank you for your reply. I do want to straighten the curve to remove distortion caused by the wide 12mm lens. It will be interesting to me to see if I like the finished result, as you say artistic.

How to reduce landscape curvature?


Which films should I see before "The Avengers"?

Question: I haven't seen any of the movies in the universe that includes The Avengers. However, this one is a Joss Whedon film, so of course I'll see it.
But first, should I go watch any other movies in that universe? Like The Hulk and Iron Man?
Comment: Just *The Incredible Hulk* should do it.
Answer: Skippable

Iron Man and Iron Man 2 are, IMO, the best movies in the current Marvel film universe. They are also not very important to understand what's going on in The Avengers - if you understand that Tony Stark is a brilliant jerk and has a robot suit, that's about all you need to know. 2 has Black Widow, but she's not really introduced until The Avengers.
The Incredible Hulk is completely missable if you're even slightly familiar with the Hulk character. It's an average action movie, hardly alluded to during The Avengers, and it's not even the same actor between the two.

Nice to See

Captain America's backstory is used often for humor and occasionally for drama. If you don't see it you'll probably miss or barely catch a lot of the jokes in the first half.

Important

Thor is mandatory - The Avengers is almost Thor 2. The main antagonist of The Avengers is the antagonist in Thor. A scientist in Thor is also a character in The Avengers and is given absolutely no introduction or explanation; if you want to understand the character dynamics in any of the scenes with him, you'll have to see Thor.
Comment: Without watching Captain America, you probably won't know much about the Tesseract, which does have a pretty large part in the plot development.
Comment: +1 for actual details, but I have to disagree with both Thor and Captain America.  I saw neither, and had no difficulty with Thor, Loki, etc. (at least once he was identified as Loki), but Captain America seemed to know a lot more than he should have.  Which I assume was covered in his movie.
Comment: @Izkata: I was thinking particularly about Selvig when I wrote _Thor_ was mandatory. He's given a lot of scenes with no real explanation of who he is and why Thor cares about him (more than, say, Hawkeye). Thor also has many subtle character beats (e.g. going to pick up his hammer) that won't necessarily confuse you if you haven't seen the movie, but you'll just _miss_ them and you'll enjoy the film less for it. Obviously some of this is mitigated if you have read a lot of the corresponding comics, but the question didn't mention any, so I figured it was best to assume no knowledge.
Comment: @Izkata On the Helicarrier, Thor refers to Selvig as a friend.
Comment: It's worth pointing out that Hawkeye was in Thor pretty much like Black Widow was in Iron Man II.
Comment: I just watched *Avengers*, and skipped *Thor* and *The Incredible Hulk*.  Now that I see this answer, this may explain why so much of the story involving Loki's plan seemed so weak and contrived....  It wasn't really confusing, but it seemed to have absolutely no depth.  I should have read this answer before I watched!
Comment: I think the section on Captain America could be fleshed out a bit.  How necessary is it if you're already familiar with his origin story?
Comment: @Keen: You'll understand Avengers just fine without having seen Captain America; it's not *necessary* at all - as long as you know who Cap is, you know all you need.  It is worth seeing, in its own right and because it has nice connections with Thor and Avengers.
Comment: @JoeWreschnig Huh, I never had the impression Thor even knew who Selvig was prior to this movie.  Alright, I'll agree that seeing _Thor_ would let you get more out of _The Avengers_, but there's nothing confusing or out of place for having missed it.
Comment: Jeff: although I think Black Widow gets more to do in Iron Man 2 than Hawkeye does in Thor.
Comment: You need to see black widow in action before Avengers (Iron man 2) to see how utterly capable and unflappable she is, seeing her "scared" at the start of the Avengers (when Ruffalo bangs the table) is sobering. I say they're all mandatory.
Answer: It should be sufficient to know the backstory of each of the characters (two of which - Black Widow and Hawkeye - didn't get a movie, and so their backstory is mostly covered in the new movie) to enjoy The Avengers. If you were a fan of the comic books you can jump right in.
However, if all of this is new to you, then it may help to see the "prequels" to this movie:

Iron Man (2008) and Iron Man 2 (2010) (good movies, both, but skippable; Black Widow makes an appearance in 2, but other than that all you need to know is that Starke is a billionaire genius, basically Marvel's version of Bruce Wayne, kidnapped by terrorists who wanted his weapons expertise and the end result of which is the first incarnation of the suit and the power generator embedded in his chest to keep him alive).
The Incredible Hulk (2008) (Hulk, from 2003, follows a slightly different canon and got mixed reviews; the 2008 film was written under closer supervision by Marvel Studios, but even then all you need to know about The Hulk is that Dr. Bruce Banner was exposed to gamma radiation that makes him transform into a big green guy with purple pants when he gets angry)
Thor (2011) (an absolute must-see, introduces Thor, Loki and Hawkeye which are all central to Avengers)
Captain America: The First Avenger (2011) (worth watching, but can be skipped if you understand who Captain America is; the key piece other than his origin is that

 he is frozen in a block of ice for the 70 years between WWII and the present day, before being found by Tony Starke and revived.

Note: Black Widow does get introduced in Iron Man 2 and Hawkeye is introduced in Thor, but their characters and backstory are significantly fleshed out in The Avengers.
Comment: I moved Hulk down a notch so the order makes more sense.  Seeing Hulk first means you don't understand the final scene, since you haven't been introduced to the visiting character.
Comment: I'd lmost put Thor last, since it seems that Loki plays a major part of the Avengers movie (going to go see it tonight so I might update my opinion)
Comment: Just got back from the film, I've added some details.
Comment: @DForck42 Captain America largely works as either the first or last film in the sequence, given that it mostly takes place during WWII.
Comment: Captain America is also the film that explains what the Tesseract is.
Answer: I believe the correct order should be:

Iron Man 1,
The Hulk,
Iron Man 2,
Thor, and lastly
Captain America.

Then of course the Avengers.
If you watch the cut scenes after the titles for Iron Man you will see Nick Fury approach Tony Stark at the end or Iron Man talking about the Avengers.  Then at the end of The Hulk, Tony comes in talking about a putting a team together and helping with the Hulk problem.  At the end of Iron Man 2, Agent Coulson shows up at the site where Thor's hammer landed in the desert, then at the end of Thor the Tesseract is introduced, and lastly, at the end of Captain America, is the trailer for the Avengers.
These are all the reasons I think this is the order.  Not just the movie content, but for the cut scenes.
Comment: The question didn't ask what *order* to watch the films in, but whether to watch them at all, and if yes, which one(s).
Comment: Minor niggle... Hulk would be first, and not really in the story line.. and "The Incredible Hulk" would be the one that's in this arc, but differnt actor, as mentioned... I'd say all but thor are skippable... I know this is an older question/answer at this point.
Answer: If you want to keep this both time and story lines correct.
1 Captain America
First movie chronologically as others have said and it introduces Shield to the story line without going overboard with it.
2 Iron Man
It continues the "super warrior" idea from a tech angle instead of a biological angle and introduces Tony Stark
3 Iron Man 2
This one brings Shield fully out of hiding and if it wasn't for the final scene in the Incredible hulk with Tony Stark knowing about the Avengers initiative, it would have gotten a fourth place position instead of the Incredible hulk.
4 Incredible Hulk
This one is a bit of a "rework" by Marvel since it trashes a bit of the story line of it's previous iteration on the accident of Hulks creation. It needs to be in fourth place though since it takes the biologically created super warrior to the next level from where Captain America left it and sneaks Tony Stark in at the end to continue the Avengers plot.
5 Thor
This one ties it all together while introducing Thor and Loki. It sets up the stage for the Avengers. Thor also sets up the reason for sheild dropping the Avengers initiative and going to plan B.
6 Avengers
It's really to bad that they reworked the creation of the Hulk. Otherwise, there could have been 7 movies in this list.
Comment: The question didn't ask what *order* to watch the films in, but whether to watch them at all, and if yes, which one(s).
Answer: I agree with most of the above statements, however going from the small snippets at the end of each movie I believe the order to be the following:

Iron Man 1 - This movie serves as an introduction to the entire Marvel/Avengers universe. The clip at the end is when we first meet Nick Fury.
Captain America - this provides back story as to how Howard Stark is involved with the Tesseract and in turn Tony, which leads to one of the main points in the plot of Iron Man 2. The ending clip states "Captain America will return in The Avengers" therefore we wouldn't see any more of the saga from the captains P.O.V. until The Avengers.
Iron Man 2 - This movie is an official introduction of Nick Fury and S.H.I.E.L.D with the clip at the end leading into Thor. We see Agent Coulson at the crash site for Thor's Hammer, this also being a scene in the movie 'Thor' as we all know.
Thor - Starting before the events of Iron Man 2 ended (evidence as per ending credits clip) this movie obviously comes next in the order to watch - ending with Dr Selvig being introduced to the Tesseract project, this leads directly to 'The Avengers'.
The Incredible Hulk - This movie isn't critical to the plot as a whole but it does well to provide how Bruce was able to control the Hulk throughout the fight with the Chitauri and how he was able to remain lucid. The ending clip shows Tony spreading the word about 'The Avengers Initiative' and going in search of Banner.

All in all, the above movies are all important if you are to understand all of the back story, banter and inside jokes that come with the awesome movie titled "The Avengers".
Comment: The question didn't ask what *order* to watch the films in, but whether to watch them at all, and if yes, which one(s).
Answer: I agree with :

Captain America (because it's merely the first in time sequence 1940's) and deals with a major part of the Avengers objective.
Iron Man 1 (due to it being first in release order, and its reference in the end).
The Incredible Hulk (not much you need to know here for Avengers. But carries its own weight in superhero development).
Iron Man 2 (leads into more of the early days of Howard Stark and Shield, which is vital to Avengers, plus the ending references to trouble in the Arizona desert).
Thor (Extremely critical to Avengers, I have to agree they could have called it Thor 2 and gotten away with it. But it was definitely The Avengers. Characters and story line of Thor are without a doubt a MUST in order to get into Avengers.)
The Avengers (crafted brilliance in this movie. Great interaction between heroes and villains alike. Hostility and ego and banter are superb, right out of the original comics. No wonder it's the third highest grossing movie of ALL TIME.

If you have an entire day (sick or bored) watching all 6 in this order would make the most fulfilling saga ever made. Makes Star Wars seem kinda blah! And I'm a Star Wars freak.
Comment: You gave the same answer as @Thomas, but +1 for actual reasons.
Comment: The question didn't ask what *order* to watch the films in, but whether to watch them at all, and if yes, which one(s).
Answer: I think you should just see them all in the order they were releases as they were all made to be watched in order to understand the MCU mythology, especially the ones released after the avengers movie a.k.a from iron man 3 onwards. I also think you should also see the "skippable" ones as Marvel can easily use them to create certain plot points in future films and you would end up not watching them and be confused.
Answer:
Hulk (2003) - not technically the same arch, but does relate to The Incredible Hulk in that it ends where the other could be thought to begin, the origin changes in The Avengers (safe to skip)
Iron Man (2008) - great film all around (recommended watch, safe to skip)
The Incredible Hulk (2008) - does give some backstory (skip unless you like hulk)
Iron Man 2 (2010) - imho not as good as the first one, still fun (safe to skip)
Thor (2011) - recommend watching before avengers, will bring a lot of the antagonist backstory for avengers.
Captain America: The First Avenger (2011) - okay, fun story, but overall safe to skip
The Avengers (2012) - object of the original question, watch
Iron Man 3 (2013) - I thought it was good, but the ending was a bit odd (status unknown)
Thor: The Dark World (2013) - status unknown, probably safe to skip
Captain America: The Winter Soldier (2014) - most likely needed to see avengers 2, though unknown how much influence it will have.
Guardians of the Galaxy (2014) - sideline story, unknown involvement, probably safe to skip
Avengers: Age of Ultron (out April 2015) - of course you want to watch it
Ant-Man (out July 2015) - meh


Not able to fill in a face between an open space

Question: I am starting to model a small character and from a tutorial I was watching and some research I from what I found, selecting the faces and or edges and hitting F would connect them with a face, however, none of that worked. I cannot connect this face right here with F or anything else. Any idea why it wouldn't be working? Thank you in advance for the help. :)
Comment: Is the object under a Mirror modifier? If so, one of the edges you are trying to fill between doesn't exist, to be a target during editing. Instead, with 'merge' and optionally 'clipping' checked in the modifier, move/scale the side which _does_ exist to the mirror plane.
Comment: check in user preferences to see if it is set to fill by the "f" key.  In 2.8, it's in the keymap settings (in 2.79 it's under Input), and the command is called "Make Edge/Face"
Comment: Oh ok thank you, I'll take a look

EDIT: It is set to F and is still not letting me create a face
Answer: By the looks of your screenshot, you do not have at least 3 vertices selected. With only two vertices selected, F will only create an edge. To create the face, try Shift+Click-ing on each of the four faces and then pressing F to fill.
Other ways of creating a bridging face:

Alt+Click, then Shift+Alt+Click on the edges to select the "Edge Loop" on each side of the gap. This will select the two connected vertices. Once all four vertices are selected, press F.
Select all four vertices with Shift+Click. Press F3 and search for "Bridge Edge Loops" and press Enter.
Press B to box select and drag a box over all four vertices, selecting them. Press F to fill.
Change to "Edge Mode" ('2' on the number row) select both edges with Shift+Click and press F to fill. You can get back to "Vertex Mode" with '1' on the number row.

If at any time, you select the wrong vertices, double tap A (dbl-A) to deselect all.
Comment: @RBlong2us you're correct. **A** only selects all by default. The **dbl-A** (double tap A) keypress is the default way to deselect all. It can be changed back to the 2.79 behavior in [Edit > Preferences > Keymap > Preferences > Select All Toggles](https://blender.stackexchange.com/questions/118778/2-8-select-and-deselect-like-in-2-79#answer-118782)
Comment: Just to let you know, I was saying I should've worded my comment differently.  I wasn't saying anything was wrong with your answer.  Now problem with making your answer even clearer, though :)
Comment: Hey, @Austin Martin, just to let you know, I don't think A is set to deselect by default in 2.8rc.  It doesn't for me, anyway.  If I'm wrong, correct me.
Comment: Ah, thank you.  I had noticed in 2.8 that the dbl-A didn't work for deselecting.  That's why I left the first comment.  Should've worded it differently.  Thank you for telling me how to change it back to 2.79 behavior.  I wanted to change it!
Comment: No problem. I've edited the original answer to clear up any confusion.


Maximum limit of charging a capacitor

Question: We say that we can charge a capacitor in proportion to the potential difference we apply across its plates and the maximum potential difference depends on the dielectric strength of the medium. Now suppose there is vacuum between the plates. Is there any limit on the maximum charge we can store in it? My concern here is for atomic properties of the material, as there is a fixed number of charges in a material.
Comment: Fun fact -- if you deplete a metal capacitor plate out of "all its charges" (so much as removing even just "one electron per atom") it simply will explode in gaseous poof of metallic ions! (especially in a vacuum) And you will no longer have a "capacitor plate" but a gas of mutually/electrostatically-repulsive particles...
Answer: The charges that accumulate on the plates of a capacitor are not provided by the material of the plates themselves but by the source that is charging them, so there is in principle no limit to the amount of charge that they can hold, if your source is strong enough.
The maximum-charge limits on actual physical capacitors are dictated by the dielectric breakdown of the medium between the plates, which typically is an insulating dielectric of some kind - common materials are paper, plastic, glass, mica and ceramics, as well as air and vacuum. In a dielectric breakdown, some of the (few) free charges in the dielectric are released by the electric field if it becomes too strong, and as they travel through the dielectric they ionize other parts of the material, setting up an avalanche reaction. The result can be a momentary spark, permanent damage to the dielectric, or even an explosion.
In air, the dielectric breakdown mode is simply avalanche sparking between the plates. If your reduce the air density between them, though, this mode becomes less and less effective, and at a good enough vacuum it will stop altogether.
The failure mode that you do get on a vacuum capacitor is leakage, which is caused by thermal electrons jumping out of the cathode and getting snatched by the electric field in the middle. This mechanism is what makes cathode rays work, but at low temperature it's still present but at much lower intensity. This effect is not a catastrophic breakdown, and it is easily modelled as the capacitor having a small component of resistive reactance.
If you really care about this (and honestly you only really care about this if you're a metrologist and you want a very steady phase reference, with low systematic errors, for AC circuits), then what you can do is cryogenically cool the electrodes, which will drive down the thermal energy the cathode electrons have available to jump out of the cathode, and therefore will limit the leakage current. For an example of this in practice, see

Capacitors with very low loss: cryogenic vacuum-gap capacitors. N.M. Zimmerman. IEEE Trans. Instrum. Meas. 45 no. 5, 841 (1996); NIST eprint.
Comment: Just for kicks, I did the calculation...
Comment: Or alternatively,  heat the cathodes a lot to produce diodes and tube -amplifiers!
Comment: Taking issue with your opening paragraph: since one electrode gets excess electrons (from an external, infinite supply) and the other gets electrons taken away (finite supply), I would say there _is_ a limit: once there is sufficient electron-deficit on the positive plate, the material stops being held together by the remaining electrons. This happens at a charge level orders of magnitude above breakdown / leakage etc. thresholds, but it should be considered an "ultimate upper limit".
Comment: @Floris fair enough, though I don't think there's a realistic experiment that will show this behaviour.
Comment: @EmilioPisanty indeed you reach other limits first - I was just responding to the final paragraph of the question ("concern for atomic properties...fixed number of charges")
Comment: if am charging a capacitor with a battery then, is it the battery that give extra charge to the plates? Actually battery is just the pump that pumps electrons from one plate to anther so i think it is the max. no of free electrons(which depend on material to material) which decides the capacitance
Comment: @Neeraj No, the separation of charges takes place at the battery itself. The number of free electrons in the conductors does not affect this (unless you're doing something crazy like saturating the conduction band, but your battery will be the limiting factor *way* before that point).
Answer: Just to expand a little bit on Emilio's answer, and to address the specific point you made in your final paragraph about "finite charges", I decided to calculate what fraction of electrons would be "missing" from the positive plate of a capacitor when you reach breakdown.
For a vacuum dielectric, the Schwinger limit is about $1.3\cdot 10^{18}\rm{V/m}$ - ignoring all other sources of field emission (see for example the extensive description of Fowler-Nordheim analysis in this article on field emission, you cannot maintain this electric field (note - it is orders of magnitude higher than any realistic field you will ever maintain).
The relationship between surface charge density $\sigma$ of a capacitor with spacing $d$ is given by
$$E=\frac{\sigma}{2\epsilon_0}$$
Setting this equal to the Schwinger limit, we find the maximum surface charge
$$\sigma_{max}=2\epsilon_0 E_S = 2\cdot 8.85\cdot 10^{-12} \cdot 1.3 \cdot 10^{18} = 23 \;\rm{MC/m^2}$$
If the conductor is copper, the size of a copper atom is about 128 pm radius. This means that the number of atoms in the surface layer is
$$N_s = \frac{1}{2\sqrt{3}(128\cdot10^{-12})^2} = 1.8\cdot 10^{19}$$
If you removed one electron per atom, you would have a surface charge of
$$\sigma = N \; e = 1.8\cdot 10^{19} \cdot 1.6\cdot 10^{-19} = 2.8\;\rm{C/m^2}$$
There are about 7 orders of magnitude between these: in other words, you will never be able to create a material that maintains its mechanical integrity and generates a field even close to the Schwinger limit.
If we assume that "one electron per atom missing" is an upper bound, this would correspond to a field of $159 \;rm{GV/m}$ - still a ridiculously high value, well above what can be maintained.
Comment: Where did the $2\sqrt{3}$ come from? Also, shouldn't the electric field inside the capacitor simply be $E = \sigma/\varepsilon_0$, without the factor of $1/2$ ? Also, if you permit "thick-enough" plates, you can probably then extract enough electrons from the material to exceed the surface $\sigma_max=23\,MC/m^2$, although those plates will probably lose their integrity as well, as extracting one electron from every copper atom will result in some weird material comprised entirely of $\text{Cu}^+$ ions likely to simply "explode" on itself over all that electrostatic repulsion!

Maximum limit of charging a capacitor


pci express connector mechanical feature

Question: What is the overhang on pci express connectors for? Is it for a rarely used board latching feature?
I am referring to the feature being pointed to in this picture.
Answer: Exactly, this feature is for optional fastening of PCIe cards and it's known as retention ridge.
Quoting from the PCI Express® Card Electromechanical Specification (Rev. 2.0):

an optional ridge feature is defined on the top of the connector housing on one side.
This feature can be used to facilitate card retention.  A retention clip may be mounted
on an add-in card and latched on the ridge.


Was Thrain aware of the necromancer's presence in southern Mirkwood?

Question: I ask this because when he foolishly went with Balin and Dwalin (I think) to retake Erebor some years before Thorin and co. actually do. He travels towards Erebor but goes through southern Mirkwood instead of the old forest road. Surely he would have known that Mirkwood was called Mirkwood because of the dark presence lying upon it, the source of which was Dol Guldur, so why did Thrain travel south through Mirkwood?
Comment: I believe it was a fairly recent occurrence, as it it the necromancy wasn't there when the mountain fell to smaug, but was by the time thrain decided to head back to the mountain. Because at the time smaug came the forests where still under pretty good protection by the elves, but after smaug the elves started to seclude themselves allow things to move in on the borders.
Comment: @Himarm - Mirkwood was named such in TA 1050; 1720 years before Smaug arrived at Erebor.  The Wise began to suspect that it was Sauron at Dol Guldur by TA 2060; 710 years before Smaug.  It's not that recent.
Answer: The short answer is that there's no particular evidence that he did go through southern Mirkwood; he was caught "under the eaves of Mirkwood" and taken to Dol Guldur.
Mirkwood was certainly evil, and almost certainly known by Thráin to be evil, by the time Thráin went there: according to the Tale of Years (Appendix B of the Lord of the Rings)

1050 ... About this time a shadow falls on Greenwood, and men begin to call it Mirkwood.
  2841 Thráin II sets out to revisit Erebor, but is pursued by the servants of Sauron.
  2845 Thráin the Dwarf is imprisoned in Dol Guldur; the last of the Seven Rings is taken from him.

So why would Thráin have gone into Mirkwood, or wanted to go into Mirkwood, at all?
At the time, according to the section of Appendix A that deals with the Dwarves, Thráin and his people had "made a home in exile in the east of the Ered Luin beyond the Lune," that is, in the eastern Ered Luin, north and west of the mouth of the river Lune. According to the Tale of Years this dates to about 2802 of the Third Age (which however states that their home is "in the South of Ered Luin"; I'm not sure how to reconcile these two statements).
A few decades later (in 2841—as Gandalf says in The Hobbit, "a hundred years ago last Thursday") Thráin became "restless and discontented" (in the words of the Appendix), and decided to try and return to Erebor. He wanted gold; and the Appendix picks up the possibility that the last Ring of the Dwarves was affecting him. To go from the Ered Luin to Erebor, the most reasonable route is roughly the same as Thorin and Company took in The Hobbit: along the Great East-West Road as far as the Misty Mountains, then through the north of Mirkwood, or alternatively skirting around Mirkwood to the north, and so more or less due east to the Mountain.
Although Appendix A doesn't specifically go into Thráin's motivations in picking a particular course for his journey, it does imply that he was trying to take the safer (relatively speaking), more northerly route. But he was a hunted person, and could not simply go where he wished:

It would now seem that as soon as he was abroad with few companions he was hunted by the emissaries of Sauron. Wolves pursued him, Orcs waylaid him, evil birds shadowed his path, and the more he strove to go north the more misfortunes opposed him. There came a dark night when he and his companions were wandering in the land beyond Anduin, and they were driven by a black rain to take shelter under the eaves of Mirkwood. In the morning he was gone from the camp, and his companions called him in vain. They searched for him many days, until at last giving up hope they departed and came at length back to Thorin. Only long after was it learned that Thráin had been taken alive and brought to the pits of Dol Guldur. There he was tormented and the Ring taken from him, and there at last he died.

From this excerpt it's not even clear that Thráin was anywhere near southern Mirkwood. Anduin parallels the western border of Mirkwood for the whole length of the forest; so the dwarves could have been anywhere in the area.
Thus, Thráin knew perfectly well the risk of southern Mirkwood. He didn't go through southern Mirkwood at all. In fact, he didn't get far into the wood, and didn't intend to, apparently; instead, he seems to have tried his best to avoid the area altogether. But he had been chased around since he had left home, and didn't have a choice of which way to go. He was effectively forced to go into Mirkwood—it was not his choice, but Sauron's, and he couldn't avoid it.
Comment: This is pretty good but there's actually no indication that he even took a route near Dol Guldur at all.  He could have been taken by Sauron's servants in a more northerly part of Mirkwood (being driven in a southward direction does not equal going all the way south) and then brought to Dol Guldur from there, for example.
Comment: @DarthSatan Indeed so! I obviously missed something. I'll have to update the answer.
Comment: @DarthSatan some slight improvements :-)


Grammatically , when can we use "you is" instead of "you are"?

Question: Can we say "you is" instead of "you are"?
For example;

"You is smart"
Comment: Based on the answers below and your specification of "grammatically" the answer is therefore "never" in correct English.
Comment: Agreed - it's wrong and you should never say it, even if you hear native speakers saying it.
Answer: The only time you would hear "you is" for "you are" is in dialect forms of English. It is incorrect in standard English.
Answer: When you are teaching someone that 'you' is a pronoun which has no singular form in Modern English.
Comment: Excellent. Or as [lyrics](https://en.wikipedia.org/wiki/Is_You_Is_or_Is_You_Ain%27t_My_Baby).
Answer: There is a time where using "you is" is correct. That situation is when you are speaking about the actual word "you." For example,

The definition of you is 'a pronoun used to refer to the person or people that the speaker is addressing.'

Other than that, you is a pronoun which has no singular form.
Answer: Is is singular, whereas are is plural.
Here is the simple answer from a question asked on ELU:

"you" is always plural. Or at least, it was so historically, and that has carried over into the present in verb conjugation.

The other answer that post offers:

is that "are" is the form of "to be" used for first person plural, third person plural, and both plural and singular in second person (with you). Thus, "are" with a singular "you" is also singular. It just looks exactly like the plural form. The same goes for "were" in the past tense, or for any other verb in second person: The form of the singular is identical to that of the plural.

Although I do think this isn't as simple.
In modern times, you is has crept in as a colloquialism (presumably stemming from this confusion), but is considered incorrect.
Comment: You always takes are but it can refer to one person or to a group of people.
Answer: "You is" is usually ungrammatical in standard English.  You cannot use "you is" as a substitute for "you are".
However, you can say "One of you is responsible", "One of you is stupid", "One of you is innocent".
Comment: That's because in the above sentences the subject is 'one' and not 'you'.


OS X: strange -psn command line parameter when launched from Finder

Question: Our OS X Java application which is launched by a shell script inside the MyApp.app bundle gets a strange command line parameter -psn_0_989382 when launched from the Finder, but not when launched directly from the Terminal. Where can I find information what this command line parameter is good for?
Comment: It also happens if you launch app via the `open` command. Interesting, that since 10.11 (or earlier?) this argument is only passed to the process on first launch.
Comment: I wonder why they chose to use a command line parameter for this, instead of an environment variable. Well, they might have had their reasons.
Comment: I experience this today and behavior is uncertain. I launched from Finder and observed MacOS _sometimes_ passes `-psn` and not always. I found it's very weird and uncertain behavior of MacOS.
Answer: Mac OS X assigns a unique process serial number ("PSN") to all apps launched via GUI. It's used for identifying various processes and instances of executables.
There's nothing I can really add to the documentation, so the best thing is to read the ProcessSerialNumber section of the Carbon Process Manager Reference (original Apple link is dead; this is a mirror).
Comment: Today, on MacOS Mojave 10.14.5, this -psn_ parameter is not normally passed to an app, except the first time when you get the "App downloaded from the internet" warning, and you click the Open button.
Comment: @ToFi Still happens today on MacOS 10.13.
Comment: BTW this answer and the docs don't really mention why the magic parameter is passed or it's format.
Comment: Though I haven't tested it, I'm not surprised. It was bound to happen someday, as Apple has deprecated all of Carbon. (Since 2008 I think?)
Answer: It seems that older applications that used the Carbon API get started with this argument. If the application was already updated to a version not using Carbon any more, you can unregister the application from the LaunchServices database by:
/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -u /Applications/AppName.app/

After this it can be re-launched from Finder to register the new version. Then it should not get this argument any more.


Calculating GSD (ground sample distance) from zoom level and vice versa?

Question: I am an application programmer, a beginner in the GIS domain. I have an image with its ground sample distance parameter. I need to associate the zoom level with GSD. I am using MapBox.
Answer: My rule of thumb is to consider that the GSD is approximately 0.3 mm on the screen at maximum magnification. You could go down to 0.1 mm for pixel peeping, but then you lose the global view without a large gain in the details (GSD is often optimistic).
Answer: Mapbox ecosystem uses tiles that are in Mercator projection (as Google Maps and other do). The GSD will vary not only with zoom level, but also latitude.
See: https://wiki.openstreetmap.org/wiki/Zoom_levels
This along with size of your tiles (usually 256x256 px or twice that for "retina" hi-DPI, you can peek your network traffic what you're getting) can let you calculate GSD.


using private key to prove the you own this account

Question: How do I ensure that the function is performed by the owner of the account using web3.js whose instance is used to call the function, I am using ganache and I have my private keys for account .
Answer: To do that you must verify the transaction's sender in your Smart Contract. For example:
function someFunction () {
    // if who sends transaction is different to 0xbb2048f1...
    // rejects transaction and refunds ETH sended.
    require(msg.sender != 0xbb2048f1be4c6e794b20502437d09552b4bc07f0);
    // if msg.sender == 0xbb2048f1... enter here
}

You can do it with Solidity modifiers
modifier onlyOwner {
    require(msg.sender == 0xbb2048f1be4c6e794b20502437d09552b4bc07f0);
    _;
}

So now you can verify who sends transactions using onlyOwner modifier
function doSomething() onlyOwner {
    // Only if sender is equals to 0xbb2048f1... enter here
    // Else do a revert(); and refund eth sended
}

Comment: but here it ensures that the contract is called from a specific account and not the person who called the function owns that account. I want to use my private key , only the owner of the account who has the key can call functions using the account .
Comment: `msg.sender` proves they have signed the transaction from that account, therefore they have the private key for that account. This is as close as you can get to proving they own the account.


If you move to a new town on a different copy of ACNL, do villagers remember you?

Question: With two different (physical, so they are both being played on separate consoles) copies of Animal Crossing: New Leaf, when your character moves from one town to another, do the villagers from the first town remember you if you go back to visit?
Answer: No. Unless a villager from the first town moves out and subsequently moves into your new town. If this is a Mayor moving, then this is not an option. But if you are moving a second player out to be a Mayor of a new town then it's possible.
You'll need to monitor your old town and when someone says they are moving and have their stuff in boxes. Have the Mayor from the new town come and visit them and ask them to move to the second town. As long as you have room in the second town (ie, you don't have all 10 residents used up), they will move over. It takes a couple of days for the move to happen.
One after thought related to the body of your question. Yes, if your new Mayor goes back to the old town where they were previously a resident, the old villagers will remember them.


Autostart under random WM?

Question: I'm a long-time DE user, however there are some circumstances under which I prefer to use different tiling-based WMs instead of GNOME or KDE (I use GNOME mostly for last year or so).
I've got Fedora 22 Workstation installation, with GNOME installed. For most time on both of my machines I run GNOME. However, sometimes I prefer to run XMonad (for me this doesn't matter much actually - i3wm, xmonad, spectrwm - for all of those 3 I've got nice configurations that I can use).
On XMonad (any non-DE e.g.), I'd like to have some scripts & programs to run when the session starts. Is there any standard way to run them without altering /etc/X11/sessions scripts?
For example, having a user-defined session for GDM or something like standard autostart files or anything. I've used to run all this through ~/.Xsession or ~/.xinitrc, but GDM doesn't execute those.
Comment: Possible workaround: http://subtle.subforge.org/blogs/show/13
Comment: It's `~/.xsession`, not `~/.Xsession`.
Answer: Try placing a symbolic link to *.desktop file of desired application into the ~/.config/autostart/ folder.

Autostart under random WM?