After the upgrade to El Capitan, Photos crashes

Question: After upgrading to El Capitan Photos app crashes after 75% of conversion process. Neither rebuilding the library launching Photos with Alt-Command had success. The rebuild process stops at 5% saying the Library was not recognized. Same creating a new library from scratch and copying inside it the Masters and Resources folders. At the moment i cannot view my 150 Gigs of photos.
See https://discussions.apple.com/thread/7252715?start=0&tstart=0
Answer: Create a new library, and import all of the other images from the Masters folder. Photos allows you to import images in sub folders, so dragging the masters folder should work.


Dojo to jQuery conversion

Question: I have a requirement to convert dojo to jQuery, for that I need to prepare analysis report.
Mentioning about time required and complicity to convert. Detailed case study. If any detailed document is available about dojo to jQuery conversion, please suggest.
Answer: There is no straight forward solution.
Dojo to jQuery conversion is not single step case, while conversion you can do part by part approach and you can have both dojo and jQuery co-exist.
Do you think, do you really need to do? Dojo is a complete toolsuite, while jQuery is a simple framework for small websites.
Please see.
http://www.slideshare.net/AddyOsmani/tools-for-jquery-application-architecture-extended-slides
and
http://www.slideshare.net/rmurphey/the-jquery-divide-5287573
jQuery can do what dojo has but again you need to set the complete architecture to get things for it. Which says, you already have a proper fully loaded advanced kit and you want to redesign from scratch and build your needs. Following your new architecture can be even end-up tricky and worse than both the frameworks documents.
Kindly think before you proceed.

Dojo to jQuery conversion


Is there a way to store some files in Gmail?

Question: I'd like to store some files in Gmail, in order to easily attach them to letters, without the need to upload them over and over again. Maybe you know of such a service? Of course there are always file hosters.
Answer: Mail the files to yourself, then forward it to the person you want to send it to - you can edit the title and add whatever you need.
Comment: I think this is your best option if you all you ever plan on doing with the files is emailing them to others.
Answer: Google Docs provides the facility to store files of any1 type by uploading them to Google Docs. From there it would be possible to email the files appending the letter text you also wanted to include into the email.
It is also possible to directly link to a file stored in Google Docs, but you might find people can't access the link due to system restrictions on which website they can access and etc.
1. I don't think this includes .exe files, unfortunately.
Answer: If you are on Linux, you can use gmailfs or imapfs, but you have to use the IMAP protocol and not the POP3 to access the mail server.
I don't know if there are other similar solutions for Windows, but you can easily check it on
Comment: I'm trying to make [gmailfs](http://sr71.net/projects/gmailfs/) work.
Comment: Failed to make use of `gmailfs` for my needs (attaching files).


Making my advisor publish manuscript

Question: I gave a manuscript to my advisor while ago but he doesn't read it, what is the best action to do cause I need to publish it fast?
Comment: _I dont want to do anything bad to relationship_ — If asking your advisor to do his job is going to damage your relationship, your relationship is already damaged beyond repair.
Comment: This is one of the positive proportion of questions asked here that makes me wish we had a **Talk to your advisor!** banner as a site feature.  How about you take the time and effort it would require to explain the particulars of your situation to a bunch of random internet academics and use that to **have a discussion** with your advisor: *why* hasn't he read your paper?  Does he intend to read it soon?  Does he understand and agree that you need to "publish it fast"?  **If** you have this conversation and run into a specific wall, then maybe we have something to talk about here.
Comment: Why do you need to publish it fast ? is there a conference deadline ? or a journal final version deadline ? or something else ?
Comment: @Katekalle Could you expand your question? Is it a paper with your advisor, or without? How long did you wait? How does he respond to reminders?
Comment: I have to publish it, because other people are publishing around it! He is telling me we are going to submit it soon. I have to graduate and there is a chance people will publish similar work. I cant publish on my own, he funded the project.
I sent him many drafts!! Nothing works, talking, sending email,... He says we ll do it and just postpones... I dont want to do anything bad to relationship!
Comment: How long ago was a while ago, to be precise?
Comment: @JeffE, I think what the OP means might damage relationship is to publish on her own.
Answer: If talking to your advisor doesn't work, I would suggest emailing your advisor with the draft, saying that you plan to submit it to XXX on such-and-such a date and that you would be grateful for any feedback he or she can provide you before then.
As mentioned by amirg, you might also run it by the head of your lab, if that's the standard in your field.  (It's not in mine: computer science.)
Comment: I would talk to your department head. Something is not going well in your department.
Comment: @ espertus; @amirg; @ RoboKaren; @Pete L. Clark; @Suresh; I have to publish it, because other people are publishing around it! He is telling me we are going to submit it soon. I have to graduate and there is a chance people will publish similar work. I cant publish on my own, he funded the project.
I sent him many drafts!! Nothing works, talking, sending email,... He says we ll do it and just postpones... I dont want to do anything bad to relationship!
Answer: Since, you are near your graduation, that means not only you know whether your research results are publishable or not but where to publish those results as well. Consequently, similar to what Suresh suggests, one of your problems is not only to publish those results but publishing them on a suitable venue which is a) close to your area of interest b) it is a high-profile journal of conference c) your paper has a lot of chances to be actually accepted. So, it is part of your job to actually find such a venue to stress the urgency of your publishing those results.
In this sense, have you checked the nearby CFPs (call for proposals) for related conferences or journals? Perhaps your advisor plans to submit your paper to an event which is 2-3 months from now and is already confident enough for your draft, so there is no immediate hurry to do the final changes now. Many advisors are very busy and allocation for their various tasks is done according to their deadlines, so perhaps this is the reason he has postponed providing feedback. If you have found an alternative venue for publishing those results with a closer deadline, it will be easier for you to convince him to check your manuscript ASAP.
But in the end, we are just random Internet strangers and the most proper solution is (as others have suggested) to TALK TO YOUR ADVISOR.
Answer: Original Answer: If you are submitting to a journal, you do not have to have your advisor's approval (unless you are using his dataset or it is coming out of his lab). If it is based on your own research findings, publish it as single-author.
Editorial Note: You did not indicate your discipline. As state in the original response, this answer is only applicable for disciplines where your research is independent of your advisor's research, lab, or research grants.
Comment: Be very careful, though, if you follow this advise, for you might needlessly damage your relationship. If you are a part of a lab, the lab head has contributed to the science the very least by getting the funds and probably by suggesting the line of research. There are many sad stories on this website alone where going single author, even when partially substantiated, have lead to probes into research integrity and other unfortunate incidents.
Comment: Oops, responded on wrong comment.That's why I added the disclaimer bit to not do this if you are in a joint lab project.
Comment: This is not a good advice. Especially when the OP is near graduation. For example: http://academia.stackexchange.com/questions/21710/how-to-respond-to-allegations-of-misconduct-in-authorship-dispute
Comment: I agree that this is **terrible** advise. Look over the question linked by Alexandros for the possible outcomes of the "ignore the advisor" approach. (-1)

Making my advisor publish manuscript


Searching and smart group for multiple event types

Question: I created a smart group through advanced search maybe 1 year ago for all contacts that had participated in an Event Type A or B or C. If I remember correctly it was very simple because the "Event Type" field in Advanced Search allowed multiple types to be selected. We now want to include Event Type D but when I go to edit the advanced search, it only allows a single type to be selected. Has the select widget for Event Type in Advance Search been changed to single select? Any ideas on how to now do a search for multiple event types?
Comment: Again, thanks @Demerit. Through the API I was able to see what had happened and figure out a way forward. I had created the original search based on the event names. However, then others started naming events with no regard to the protocol I had developed so that no longer worked, which I should have known would happen.
Comment: Daniel - can you now Answer your own Question as Stack Exchange likes to know that answers happen
Comment: What you might have done was create three smart groups separately from single event type searches, then combine on advanced search using the groups field there which does allow multiple. When editing the smart group what's in the groups field, in the basic criteria section?
Comment: Thanks, @Demerit for the idea but, no, I did not do that. This is the only smart group we have. When I go to edit the smart group search, it has no criteria whatsoever so, now it is just returning all contacts in the database.
Comment: If you go to /civicrm/api3, and then for Entity choose "SavedSearch", then click the Execute button at the bottom it will output some gobbledygook. Can you edit your question post and copy and paste that in there (it will be too big for a comment). If you put three backticks before and after it then it will format properly (https://stackoverflow.com/editing-help#code).
Comment: Ahh, makes sense.
Answer: Using the API3 interface I was able to see the information I needed to work though this problem. See the comments.
Answer: Note that there has been a request since 2017 to request this functionality at Multiselect for Event Type in Advanced Search.
Answer: With the new search interface SearchKit now it's possible to get this type of smart group in an alternative and easy way to advanced search.


Best succinct wording for app field

Question: I am just making a little app and it collects team data. One of my fields is "number of players". In this sense I mean how many players are playing on the pitch at any given time. But it could certainly be construed as how many players are in your roster. So i'm a little stuck as to a better way to word this? Any ideas would be great
Answer: Perhaps you could solve this with some data organization. Provide context to the data you're collecting.
Group data related to the pitch together, and group data related to the roster together.

download bmml source – Wireframes created with Balsamiq Mockups
Answer: More context around your app and needs would certainly help better provide a solution, but how about simply labeling the field "Players on Pitch"?
Answer: Number of active players or number of starters would work.
Answer: You could set it as a question that the user will answer.

How many on you roster?
How many on the pitch?

May seem verbose, but clearer.

Best succinct wording for app field


How can I fix my nvidia display problem in Ubuntu 9.10?

Question: I had Ubuntu 9.04 working with nvidia display drivers, then I upgraded Ubuntu to 9.10.  It boots to the desktop, the desktop looks great for a moment and then I get a screenful of pink and blue noise.  How can I fix this?  I've read that I should be able to drop out of the GUI with Ctrl-Alt-F1, but that doesn't work.
Comment: are you running 64 bit or 32 bit?
Comment: running 32 bit.
Answer: I got the help of a friend and here's what he ended up doing:
Booted into recovery shell.
Edited /etc/X11/xorg.conf and changed "nvidia" to "vesa".  This allowed us to run the desktop GUI without getting the problem.
He then went to the list of available display drivers under the "hardware drivers" menu and we selected a previous version of the nvidia proprietary drivers (just previous to the latest).  The package manager downloaded and installed these drivers.
We then changed "vesa" back to "nvidia" in xorg.conf, rebooted, and everything was good.  The reason I couldn't drop out to a shell from the start was that the video problem seemed to kill the keyboard too.  We also tried connecting an external monitor per DigitalRoss, but we never got anything to display.  So the bottom line is that I'm not on the latest nvidia drivers, but at least I didn't have to downgrade anything else.
Comment: I am having this same issue. What version of the nvidia driver did you end up using?
Comment: NVIDIA accelerated graphics driver (version 173)
Answer: Go to System > Administration > Hardware drivers
Then activate the recommended drivers.  If you've already done that, it most likely is a bug.  There have been a lot of reported bugs in 9.10
Comment: I just have noise on the screen and can barely see the mouse move, so I can't use the menu
Comment: sounds like bugs to me, id downgrade to 9.04 until they've figured everything out with 9.10...  I don't see how you're supposed to activate the drivers without being able to see anything.  Try rebooting and see if you have enough time before your screen messes up to activate the drivers.
Comment: There is very little time before the screen turns to noise.  I can boot in recovery mode to a root shell.  Can I downgrade from there?
Comment: honestly i think its better for you to post this in the ubuntu forums, easier for the back and forth.  Here is a downgrade howto https://help.ubuntu.com/community/DowngradeHowto
Comment: if you are posting on another forum, please let us know when you find a solution in case someone else has the same problem
Answer: If there is a Fn key on your keyboard, you might want to try Ctrl-Alt-Fn-F1 to get to the text console. The F1 to F6 keys will get you to separate text consoles, and Ctrl-Alt-Fn-F7 will get you back to the GUI.
Check this thread on UbuntuForums if you want to mess with the NVidia VGA driver.
Comment: Ctrl-Alt-Fn-F1 doesn't seem to do anything but Ctrl-Alt-Fn-F2 seems to turn my fan off  :-)
Answer: The problem you are having is not precisely with Ubuntu, except in the sense that they take some responsibility for setting up Xorg and for including drivers for the text-based consoles.
What you really need to do is find an <code>/etc/X11/xorg.conf</code> that works. On a cast-off Inspiron 8000, notorious for not running Linux (unless you have never-"up"graded firmware) I managed to get Ubuntu 9.04 working after some pain. I ultimately found out that the issue was that the Dell firmware was providing bogus data on frequency ranges and so xorg was rejecting all the workable modelines.
I was able to make the system usable for debugging by plugging in an external LCD to the VGA port. Another way would be to boot up into text console mode rather than X, which I believe can be done by having GRUB boot into "recovery mode". (I didn't have to try that due to the external monitor.)
Fixing your Xorg Xserver is going to be painful and it deserves a separate SO question so I don't have to answer it. At least if you can get going in console mode you have a chance. The kernel's console driver is considerably less ambitious and less prone to failure than the Xserver driver.
(And I should add a note: it looks like I have blamed Xorg, but really the problem is the secrecy surrounding the video chips. Because they are afraid of patent wars, they publish no interface info. It's really a pity they don't make an exception for the tiny part of the chip that does the 2D stuff, and it's unfortunate that the patent court and other influences have made the USA such a legal minefield.)


Voltage drop problem with my solid state relay

Question: My solid state relay seems to be dropping the potential by 35 volts.  I read about 80 volts from one end of a modified plug and the other end is plugged into a 120 volt wall socket.   I have the hot wire cut and the ends connected to the leads of the relay.  The neutral wire is not cut anywhere.  I knew there would be a small internal resistance but not by this much.  Is there something I am missing?  I would simply like to control a 120 volt lamp with my arduino.
Answer: More than likely what you are seeing is the leakiness of the SSR when it is switched off. Lets say you meter has 10 Mohm input impedance - the 80V implies a current of 8 uA which in turn implies the SSR has an open-circuit impedance of 35 v / 8 uA = 4.38 Mohms.
Else, the SSR is broken!
Answer: Zero-voltage switching type thyristor SSRs sometimes require a minimum load current.
The gate trigger pulse for the thyristor is generated near the mains zero crossing. If there is insufficient load to reach the minimum holding current (of the pilot device in the case of an opto-triac), then the pilot thyristor switches back off until the next zero crossing- the gate trigger does not persist past the window around the mains zero crossing. Since the holding current of the main triac will be much higher than the pilot triac, the SSR will only turn on for a brief time when the mains voltage is very low. If you've got a meter connected, you'll measure leakage current through the triacs (and possibly a snubber circuit).
Take the MOC0603 opto-triac output optocoupler. This device must see a current exceeding its holding current of 0.5mA before the mains voltage exceeds about +/-12V or the opto-triac will turn off again and never trigger the main triac. Below is a simplified schematic of an SSR with a zero-crossing circuit.

That means that the load resistance RL must be less than 24K ohms (typically, at room temperature) for the SSR to turn on for the full cycle.
If you connect a reasonable load to the SSR (there may be a specification in the datasheet, 100mA is a common requirement for minimum load) then you should measure mains voltage across the load when the input is "on", less a volt or two.


What is the saturation point of dishwashing soap in water?

Question: I am looking to measure the effect of dishwashing soap on the surface tension of water. To select appropriate values for the concentration of dishwashing soap is to find the saturation point first, but I can't find any values for it and don't know how to measure it. How can I select appropriate values for the concentration and if finding the saturation point is a way of doing that, how do I find the saturation point of dishwashing soap in water?
Comment: Dishwashing soap is a generic term. Different brands contain different mixtures of multiple surfactants and other additives in various concentrations and ratios. You would have to restrict the question to a single compound or a products, as the value is generally different for each. // You may want to search for *surface tension measurement*, e.g. [Tensiometer](https://en.wikipedia.org/wiki/Tensiometer_(surface_tension))
Answer: Critical Micelle Concnetration (CMC) is a commonly used parameter to measure when a solution is saturated with surfactant (soap).
CMC is the concentration where the surfactant starts to form small droplets (micelles) instead of spreading out onto the water/air surface.
One way to determine CMC is by measuring the surface tension. When the surfactant concentration is (very) low, the surface tension more or less linearly decreases with increasing concentration, but at some point the surface tension reaches a constant level, as Poutnik mentions. This concentration is called the CMC.
Kruss tensiometers: CMC and surfactant concentration
Answer: I want to point out that saturation usually refers to a situation where chemical precipitates out of solution, but it seems you are interested in soap's effect. That's very different thing.
Soap's effect is very dependent on a situation - amount of evaporation and even type of soap. But in general even few parts per million can greatly change parameters. And then even a few percents won't change much further. While actual saturation is even further, at equal parts or so.
Something like this:
1 part per million - bubbles are normal size
100 parts per million - bigger bubbles
10 000 parts per million - bubbles are large
100 000 parts per million - bubbles are as large, but you can keep dissolving soap as much as you want
Why is it so? Unlike most materials like salt and conductivity, soap's effect doesn't rely on how much soap is in the bulk of water. Soap acts only on the water's surface. As you make a bubble, soap accumulates on bubbles' surface. And because molecules are small, you have a lot of volume against small amount of surface area. So, even few parts per million in water's volume can mean almost complete fill of soap bubble's surface. And if soap bubble's surface is filled with soap molecules, nothing will happen if you keep adding soap in water's volume.
What it can affect is how much evaporation is needed for soap's film to form fully, or how thin can you extend a soap film.
If you want to make bubbles that are more than 10cm, you will need to use more tricks than just soap. Water itself evaporates too quickly at that point. You can fix it by adding glycerine, it evaporates slower. Adding just more soap won't help make bubbles bigger after this point.
Anyway, soap is very different than all other chemicals, because it acts on a surface, rather than in volume. And it is better to ask more specific question, than trying to use a term that doesn't help much with it.
If you meant what you asked, you can mix about equal amounts of liquid soap and water. But for most uses it is too much.
Comment: I suppose the OP may mean saturation in mathematical meaning, where value of measured quantity reaches a plateau on the curve of its dependence on other quantity. Like surface tension not decreasing with another soap addition any more.


Best way to mix essential oils with water?

Question: I am using alcohol as an emulsifier. Of course, I can use a lot of alcohol to mix the oil and water but I do not like the color and the % of alcohol in the mix. The best mix I made was 10ml water, 0.5ml (10 drops) essential oil, 5ml alcohol because the mix looks super milky and when left alone the oil does no lt deposit. I repeated this formula again but the result is different (maybe the temperature was different, or the stirring, etc). My question is: what is the best way to stir the essential oil with the alcohol? Should I heat it? Should I stir it with an instrument other than just stirring in a beaker? All emulsifying tips are welcome!
Comment: I want to make a stable emulsion. If I put too much alcohol the mix turns yellow. If I put too little alcohol the oil does not mix with the water. If I put too much alcohol the mix becomes flamable. The perfect mix should turn it into a milky white, but I cannot accomplish it constantly. I use alcohol because it is cheap and easy to get anywhere.
Comment: I am not sure if what I need is defined as a solution or emulsion; I want to spray essential oils diluted in water, but need the best result to make the water and oil mix without having to shake the bottle every time. – Giancarlo 1 hour ago   delete
Comment: It is not really clear what you would like to reach. Do you want to make a stable emulsion? I cannot compute what does "I don't like the % of alcohol in the mix" or color (isn't it white??) mean. Also, why do you use alcohol as emulsifier?
Comment: First of all, alcohol is not an emulisfier but a cosolvent. Please specify whether you want to obtain a homogenous solution, emulsion or dispersion. These are three different goals and require three different approaches.
Comment: Any tips or recommendations?
Answer: A solution would be the best for spraying, and it would require dissolving the essential oil in an appropriate organic solvent. However, if you are concerned about the flammability, then a dispersion in water would be your best option. Basically, all you need is a stabilizing agent and a proper procedure. I am sure that you will find all the necessary information on this site. It has all the basics about emulsions, it lists various emulsifiers (stabilizing agents) and procedures. For your purpose, I think the best option would be the Bottle Method.
Comment: Those two html pages are not available.  Can you provide the information here?
Answer: To make an emulsion, a stable milky mixture of oil and water, you need an emulsifier. Alcohol is not an emulsifier, so the mixture will separate at some point.
The most common emulsifiers used in cosmetics can be found here.
If you are making this at home and do not have access to these kind of products, you can try with organic soap. This is normally oil hydrolyzed with caustic soda (NaOH) and is in essence what is listed as neutralized fatty acid soap.
Normal stirring is also many times not enough and a high shear mixer is generally used. So mix it as hard as you can.
Comment: The link you shared is not available.  Can you share the information here?
Answer: By alcohol, I assume you mean ethanol. A better choice might be isopropanol (rubbing alcohol). If either ethanol or isopropanol can be mixed with your essential oil in a 10:1 ratio to give a clear solution, then the alcohol is a solvent. The water is not a solvent for the essential oil, but the alcohol might be able to dissolve some water without expelling the oil.
I suggest you make a triaxial graph to plot the concentration ratios of ingredients that are clear (solution) or milky (stable (?) emulsion) or quickly separating (unstable emulsion). The advantage of a triaxial graph is that you can find a location on the equilateral triangle for any combination of three ingredients - and do some interpolations to find where you can be. This is a picture of a triaxial graph:

It might be possible to use another solvent, e.g., acetone, in whole or in part. One way to stabilize an emulsion is with surfactants; high shear is best for reducing the size of the micelles. Another way to stabilize an emulsion is to use a thickener that prevents the oil micelles from settling or creaming.
Comment: @user12711: The 10 to 1 ratio is to determine whether the oil is soluble in pure alcohol (i.e., isopropanol). If so, maybe water can be added. But some oils are not soluble even in pure isopropanol, so the mixture will be cloudy and will probably separate. In this case, adding water will not help. The OP made one successful mixture, but could not replicate. Using a triaxial graph can map what compositions are useful. It may show how some compositions are milky, some settle, some are clear, depending on composition. Procedure (heating, stirring) needs other experiments.
Comment: I'm trying to make a 1 to 2% solution of cedarwood oil with water/alcohol (rubbing) to spray for fleas inside a living space.  My plan is to mix my 1 ounce bottle of pure essential oil with 10 ounces of isopropyl.  That should look milky white.  Then I'm going mix that with 5 to 10 parts water to make the ultimate solution stable enough to shake once and spray for several minutes (1 to 2% cedarwood oil).  Should that work?
Comment: actually more 70% isopropyl will need to be mixed than 10 to 1 ratio because it's only 70% ??
Answer: You can use ultrasonication and no solvent (water + oil + sonicating = emulsion). The sonicator degasses the water which allows the oil to disperse homogeneously throughout the water.
I hope you can access a sonicator if not there are freezing techniques which also degas water.


Where does the phrase 'Crazy as a Coconut' originate from?

Question: I recently overheard someone referring to another person as being 'Crazy as a coconut'. I hadn't heard this phrase before so later on I started researching. My initial thought was that he had made up himself as I didn't find many results. I did however see this phrase used as lyrics in a song by a band called 'The Avalanches' titled 'Frontier Psychiatrist'.
I see someone else had raised question on Answers.com and received an obscene response but hoping someone here might provide a more helpful response as to its origination.
Comment: Understand that "crazy as a X" is a common expression, with many different objects being used for X.  It's often ad-hoc.
Answer: The phrase is "crazy in the coconut":

Popularized by the Australian electronic music group The Avalanches in their song "Frontier Psychiatrist".

Lie down on the couch, what does that mean?

You're a nut! You're crazy in the coconut!

What does that mean? That boy needs therapy

It refers to the slang meaning of coconut as head whose usage dates back to the first part of the 19th century.

1848 -    Bell's Life in Sydney 30 Dec. 2/6: Kenny shook his cocoa nut like a mandarin in a Ludgate Hill Grocer's.

(GDoS)
Answer: When the coconut was brought back from the tropics people found it so strange milk from a nut strange delicious pulp found up a tall tall tree SO STRANGE & CRAZY!!!! so crazier than a coconut.
Comment: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).


How would you make something like this using illustrator?

Question:
How can I calculate the necessary transformations to construct circular path and maintain the pattern? Can anyone provide me with or reference to relevant resources? Thanks!
Answer: You could use a polar grid, and a grid of vertical lines snapped to the edge of each circle, then use the shape builder, delete the outer vertical lines, and fill in the chequered pattern.
For example
Making the grids, and using the shape builder to delete the outer lines

Using the shape builder to create the pattern
Comment: Your step-by-step explanation using a polar grid and the shape builder tool is incredibly insightful. It's a brilliantly simple method I wouldn't have even considered. Do you have any recommendations for resources or books that delve into these kinds of techniques? I'm eager to expand my understanding of design principles, especially in the way you've demonstrated here. Learning more about how different elements and forms can be constructed and manipulated in design would be extremely beneficial. Thanks again for sharing such a clear approach!
Comment: Youtube is good resource for learning how to draw specific things in Illustrator.
Answer: I'm afraid there's no single nor 2  click effect available for the wanted effect.
As already said by others it can be got by dividing a set of concentric circles with vertical lines and by filling half of the areas which are formed by the intersection.
Filling the areas with the shape builder may take while, if there's say 30 circles an 60 vertical lines, but there's another approach for faster result. Essentially it also divides concentric circles with vertical lines, but it needs less clicks.

In the left there's a white and a grey rectangle aligned side by side . Both rectangles are exactly 4 mm wide. A duplicate is made and rotated 180 degrees.
Both rectangle pairs are dragged to the swatches panel. It generates 2 fill patterns which are otherwise the same, but white and grey are in the opposite places.
There's a set of concentric circles. The smallest one is 8 mm wide, the next is 8 mm wider, the next is 8 mm wider (etc) and the biggest one is 80 mm wide. As well one could say the circles are concentric, but their radiuses are 4,8,12,16, 20, 24, 28, 32 36 and 40 millimeters. The largest circle is in the bottom of the layering order and the smallest is on the top.
The easiest way to get these circles is the polar grid tool. The grid should have with and height = 80 mm and have 9 concentric dividers.
In Illustrator Blending is the other easy way to get numerous modified copies of a shape, but the polar grid is perfect just in this case. The circles must be ungrouped. It must be done twice to get them all free. The layering order becomes right by default.
The circles which have widths 80, 64, 48, 32 and 16 mm are selected in the same time  (hold shift and click he wanted ones). They all got the first fill pattern. The rest of the circles got the second fill pattern. The strokes are removed.
This method has 2 drawbacks:

You must select all circles and move them to the left edge of the artboard to force the fill pattern to start at the edge of the largest circle. Illustrator relates the fill pattern to the artboard. To make the shapes freely movable the fill pattern must be expanded (Object > Expand > Fill)

After expanding the fill this is still a bunch of circles. They must be grouped to keep then surely together. In addition the circles are clipping masks for a big bunch of white and grey rectangles. Many of us will not want to have such burden behind the curtains, because it shows its existence as soon as the mouse hovers over it (an outline ghost) and it's not a path which could be used as a path in other effects.

It looks right, but it has a massive invisible complex behind the visible part. There's no easy way to convert the internal structure of the result to as simple as what's got with the shown shape builder method.
Definitely not asked and not useful in this case, but check the next Illustrator functions 1) Art Brush 2) Pattern Brush 3) Scatter Brush. They all offer ways to make a pattern to follow a curve, but differently. If they happen to be new things for you, you will probably soon find ways to utilize them. I believe even GDSE contains hundreds of them.
Comment: Thanks a lot for this explanation! I played around with your example today, along with the advice from the previous comment, and it worked perfectly. Has  opened my eyes to new possibilities in Illustrator.

I'm now interested in diving deeper into this type of geometric and pattern-based thinking. Do you have any recommendations for books or resources that could help sharpen these skills further? I've been wanting to improve my understanding of geometry and pattern design in a creative context, but I'm not quite sure where to start with this mode of thinking.
Comment: YouTube and many other sites are full of "how to draw this" tutorials. GDSE is one of them., no matter many users would like to see something finer. "What is this font" or "What's the name of the style of this drawing" are not such finer questions. Try at first to to work along some Indian and Arabic style pattern drawing tutorials. Another way to see a pattern is to imagine it as an obscure 3D item. Your example could well be a headache causing tunnel. How to insert the extras which create the illusion of 3D depth is an area worth checking.  I do not have any recommendations of books.


How can I prove that a Regular Language is closed under Union given two languages with different alphabets?

Question: I need some help to prove that a Regular Language is closed under the union, using a DFA with two differents alphabets.
Comment: Have you seen the normal proof that the union of two regular languages on the same alphabet is closed? If so, take a moment and think why having two different alphabets doesn't really change anything. If not, you're probably ahead of yourself.
Answer: Suppose you have alphabets $\Sigma\subseteq\Sigma'$.  You can view any language $L\subseteq \Sigma^*$ as being a subset of $(\Sigma')^*$: it just happens to be language of strings that don't contain any symbols from $\Sigma'\setminus\Sigma$.
So, given languages $L_1\subseteq \Sigma_1^*$ and $L_2\subseteq\Sigma_2^*$, you can view both of these as languages over $\Sigma_1\cup\Sigma_2$, since $\Sigma_i\subseteq \Sigma_1\cup\Sigma_2$ for $i\in\{1,2\}$.  Given automata for $L_1$ and $L_2$, you can also modify them to work over alphabet $\Sigma_1\cup\Sigma_2$.
Now, you have two languages over the same alphabet, so you should be on familiar ground.
Comment: I see now, my dificulty is the function of transition of the DFA, I need to change it, and can't see how. Any advice?
Comment: If $L\subset\Sigma^*$ then what do you know about a string that contains some character not in $\Sigma$?
Answer: Using the accepted answer by @David Richerby ->
I think what we have to do is modify the DFAs that recognize L1 and L2.
Let L1 alphabet Σ1 and L2 alphabet Σ2,
let    Σ = Σ1 ∪ Σ2
let's say we have DFA for L1 called M,
For M DFA add a extra state called y and for all the letters in Σ but not in Σ1 add a transition from all the states of M to state y. then for all the letters in Σ add a transition from y state to y. Then we have a new DFA (let's call it M1) that recognize the same strings as M DFA but, over Σ alphabet rather than Σ1 alphabet.
we can do the same for L2 language and create a modified DFA with alphabet Σ.
Then we can use them to create a new DFA that can prove the Regular Language is closed under Union given two languages with different alphabets.


leaflet remove a specific type of features from featuregroup

Question: Is there any way in leaflet to delete  a specific type of features from a feature group (mixed content: markers, polygons, polylines)? I know this code that work: map.removeLayer(drawnItems); but it delete all the objects within the drawnItems featuregroup. I only need a specific type of features, for example all the markers to be deleted.
Answer: In a similar way to my answer to leaflet count by featuretypes in featuregroup :
drawnItems
  .filter(function(layer) {
    return layer instanceof L.Marker;
  })
  .forEach(function(layer) {
    map.removeLayer(layer);
  });

Or in a shorter one-liner using arrow functions:
drawnItems.getLayers().filter(l=>l instanceof L.Marker).forEach(l=>map.remove(l));

Remember to check the documentation for Array.prototype.filter and Array.prototype.forEach.
On the other hand, you should consider creating several L.FeatureGroups, one for each kind of layer you want to add/remove from/to the map.
Comment: thank for your help and for the useful tips. I tested the code and it generates -drawnItems.filter is not a function- error for some reason. I tried to modify but no succes..
Comment: Not "some reason". If `drawnItems` is an instance of `L.LayerGroup`, then it's not an array. OTOH, `drawnItems.getLayers()` returns an instance of `Array`, which has a `filter` method.
Answer: if(map.hasLayer(drawnFeatures)){
    // map.removeLayer(drawnFeatures); <-- this the wrong way
    drawnFeatures.eachLayer(
        function(l){
            drawnFeatures.removeLayer(l);
    });
}

that can delete each layer without delete Features group. can be used again for new drawn items.


JavaCV Vs OpenCV from Runtime point of View

Question: I am building an Android App that includes image processing techniques. From the Runtime point of view, which is better JavaCV or OpenCV ?
Answer: Their runtime overhead seems to be about the same, but the android-opencv wrappers do not give access to raw data via direct NIO buffers, rendering custom processing in Java a lot less efficient. JavaCV is more efficient for those tasks. Being the author of JavaCV, I also like its API better :) It's closer to the original C/C++ API than android-opencv.
EDIT: Another difference is that android-opencv forces users to use the NDK and JNI to write functions. Since JavaCV is based on JavaCPP, we can write native functions more easily without having to deal with neither the NDK nor JNI.
Answer: Writing native code using Android NDK will usually be much faster than using the SDK.
You can find nice tutorial here, using opencv with NDK. Notice that with NDK framework you have access to openGL functions.
Answer: JavaCV is just a Java wrapper around the native OpenCV library.  OpenCV does provide a Java/SWIG binding.  I have used both bindings and didn't see a significant difference between the two.
If you are writing a native only app go with native OpenCV.


TFS: "Source control folder" as parameter in build definition

Question: As i understand the "Source control folder" (under "Source settings" tab of build definition) is used to specify the path from where the source code will be downloaded.  Is there any way this can be made as build parameter?  If so, please share the solution.
Reason: In our project there are several branches and each of them has its own build template and build definition settings, the above solution will help us in creating just one build definition for all the branches.
Thanks in advance.
Regards,
spm
Answer: You can try to add download files activity in templates and pass the source control path as a parameter.


Create a function in Python to check for the data errors

Question: I'm trying to create a function to check multiple conditions of data.
The function will return a list if the data is errors.
Here is my idea:
error_lists = []
def check(A, B, C, D, E):
    check condition 1 for A
    if there is a error -> error_list.append(1)
    check condition 2 for B
    if there is a error -> error_list.append(2)
    check condition 3 for C
    if there is a error -> error_list.append(3)
    check condition 4 for D
    if there is a error -> error_list.append(4)
    check condition 5 for E
    if there is a error -> error_list.append(5)
return error_list

If A, B, C do not meet the requirement, the function will return the error_list: [1,2,3]. Likewise, the function will return [2,5] if only B or E do not meet the requirement
Actually I've already written the code, however I feel that it need to be improved.
P_list = [35000, 50000, 80000, 120000, 150000, 180,000]
def data_check(Staff_id, A ,B, x, y, z, t, u, D):
    error_list = []
    wh = x + y
    tot = z + t
    C = [x, y, z, t, u]
    """First condition"""
    if A not in P_list:
        print(f"Error type 1 in the data of {staff_id} {A} is not True")
        error_list.append(1)
    """Second condition"""
    if B >= 48:
        print(f"Error type 2 in the data of {staff_id} {B} is not True")
        error_list.append(2)
    """Third condition"""
    for k in C:
        if k < 0:
            print(f"Error type 3 in the data of {staff_id} {k} is less than 0")
            error_list.append(3)
    """Fourth condition"""
    if D >= 3000000:
        print(f"Error type 4 in the data of {staff_id} D is not true")
        error_list.append(4)
    """Fifth condition"""
    if tot >= wh:
        print(f"Error type 5 in the data of {staff_id} E is not true")
        error_list.append(5)
    return print(error_list)

data_check("1a88s2s", 50000 ,71, 23, 28, 3,5, 12, 3500000)

Does anybody has any suggestion ?
Many thanks
Comment: Welcome to Code Review! It appears there is a slight flaw with the code: "_NameError: name 'staff_id' is not defined_" - it can be fixed by changing the case on the argument.
Answer:
P_list should be a set, not a list, based on its usage; it's only used for membership checks. You can also pre-bind to the __contains__ member to get a function reference you can call, constraining the set to one purpose.
Add PEP484 type hints
C should be a tuple based on its usage since it's immutable
Your print statements should not be mixed in with your logic, and should be separated to another method
Consider representing your errors not as free integers, but as constrained enumeration values
Use an any generator for your C negative check
180,000 is likely incorrect and should be 180_000
return print is meaningless and will always return None; instead consider returning your error values or yielding them as a generator
staff_id shouldn't be passed into data_check at all; it's only used for formatting error messages which again can exist in a separate method
Your letter-salad variable names are helping no one. You need to spell out what these actually mean.
Moving your intermediate error-checking variables C, wh and tot closer to where they're used is, I think, clearer

Suggested
import enum
from enum import Enum
from typing import Iterable

in_p_list = frozenset((35_000, 50_000, 80_000, 120_000, 150_000, 180_000)).__contains__

@enum.unique
class ErrorType(Enum):
    REJECTED_A = 1
    B_TOO_HIGH = 2
    NEGATIVE_C = 3
    D_TOO_HIGH = 4
    TOTAL_TOO_HIGH = 5

def data_check(
    A: int,
    B: int,
    x: int,
    y: int,
    z: int,
    t: int,
    u: int,
    D: int,
) -> Iterable[ErrorType]:
    if not in_p_list(A):
        yield ErrorType.REJECTED_A

    if B >= 48:
        yield ErrorType.B_TOO_HIGH

    C = (x, y, z, t, u)
    if any(k < 0 for k in C):
        yield ErrorType.NEGATIVE_C

    if D >= 3_000_000:
        yield ErrorType.D_TOO_HIGH

    wh = x + y
    tot = z + t
    if tot >= wh:
        yield ErrorType.TOTAL_TOO_HIGH

def print_errors(staff_id: str, errors: Iterable[ErrorType]) -> None:
    for error in errors:
        print(
            f'Error type {error.value} in the data of {staff_id}: {error.name}'
        )

def test() -> None:
    print_errors("1a88s2s", data_check(50000, 71, 23, 28, 3, 5, 12, 3500000))

if __name__ == '__main__':
    test()

Output
Error type 2 in the data of 1a88s2s: B_TOO_HIGH
Error type 4 in the data of 1a88s2s: D_TOO_HIGH

Comment: Thank you so much for your response @Reinderien!
Answer: Adhere to PEP8
Like keep the style of identifiers consistent. data_check, Staff_id, A ,B, x, y, z, t, u, D - what style is common for all those names?
You can pass a list as an argument
No need to write so many arguments and gather them in a list - you can gather them when you call your function and pass only one c argument. The call will look like
data_check(staff_id, A, B,  [x, y, z, t, u], D)

Also you can gather all trailing arguments in a list with * (the call whouln't change).
Use the loop
All the conditions are simple (one expression), all the messages are almost uniform. Thus, you can use the loop like this:
def data_check(staff_id, *args):
    conditions = [lambda x: x not in P_list,
                  lambda x: x>=48, #are you trying to compare with '0'?
                  lambda x: any(i<0 for i in x),
                  ...
                 ]
    result = []
    for i, (condition, arg) in enumerate(zip(conditions, args), 1):
        if not condition(arg):
            result.append(i)
            printf(f"Error type {i} in the data of {staff_id}: {arg} failed")
    return result

You can change lambdas to local functions; this can make the code more readable (with correct names):
def data_check(staff_id, *args):
    def not_in_p_list(x):
        return x not in P_list
    def greater_then_48(x):
        return x>48
    def any_less_then_0(x):
        return any(i<0 for i in x)
    conditions = [not_in_p_list,
                  greater_then_48,
                  any_less_then_0,
                  ...
                 ]

Of course, you can (and should) give conditions more informative names, like not_listed_in_registry or negative_weight.
Comment: Thank you so much for your response @PavloSlavynskyy !


Relative velocity greater than speed of light

Question: Is it possible a relative velocity between 2 objects to be greater than the speed of light?
I know that it is impossible to reach the speed of light considering us to be immobile but is this different?
Answer: Velocity is frame-dependent.  If by "relative velocity" you mean the difference between the two objects' velocities, then (in any given frame) the speed of each object is limited to $c$ so their relative velocity can be anything up to $2c$.  If you mean to choose a frame in which one of the objects is stationary, then, as the other answers have said, the limit is $c$.
Answer: If you shoot one object to the east with speed 0.75 c and one object to the west with speed 0.75 c, then in your frame of reference the relative speed of the objects will be 1.50 c.
But in the frames of each of these objects, the other object will have a speed of only $0.96 c.$
So your question might be interpreted so that the answer can be yes, but the way I think that you meant, the answer is no.
If we transition to general relativity and an expanding universe, then for objects that are separated with a big enough distance, their relative speed can exceed the speed of light in such a way that they can not send signals between each other.
Comment: @Silica19. [The addition law of speeds in relativity](https://en.wikipedia.org/wiki/Velocity-addition_formula#Special_relativity) gives
$$\frac{0.75\ c + 0.75\ c}{1 + 0.75\ c\cdot 0.75\ c / c^2} = 0.96\ c.$$
Comment: How did you get $0.96c$?
Answer: Let's say that due to an explosion, two space ships at a space dock were blown apart from each other and are now moving in opposite directions, with each now moving at a spacial velocity of 0.866c relative to the space dock, but again moving in opposite directions.  They will therefore be moving apart from each other at 1.732c.
Now imagine that we had two massively long objects that were side by side, and that one was moving to the left along side of one of these two spaceships, and the other was moving to the right along side of the other spaceship.  Despite the fact that these two long objects were relatively in motion a total of 1.732c, if those on board either of the two long objects were to measure the velocity of the other long object, they would measure that they were moving relative to each other at a total of 0.98974c velocity, not 1.732c.
The key to understanding relativity, is to understand exactly why this occurs.
Answer:
Is it possible a relative velocity between 2 objects to be greater than the speed of light? I know that it is impossible to reach the speed of light considering us to be immobile but is this different?

Usually the term "relative velocity" means the velocity of one object in the reference frame of the other object.  It turns out unsurprisingly that my velocity in your frame is equal and opposite to your velocity in my frame, so our relative velocity is the same regardless of which of us is considered to be immobile.  So it is not different: if you consider yourself immobile and me moving or if you consider me immobile and yourself moving our relative velocity is still less than c either way.
Comment: But you could have a third observer standing in the middle and see both objects moving away in opposite directions at more than 0.5c, yet the relative velocity between those objects is still less than c.
Comment: Yes. The difference in velocities in a 3rd reference frame is limited by 2c, but the relative velocity is limited by c.
Answer: Velocity is definitonally the same as "relative velocity". This is the point of the first postulate of relativity.
Answer: The answer you're probably looking for is NO. Suppose you have to spaceships that start at the same location but zip off in opposite directions from each other each traveling at the speed of light (c).  The conventional way to calculate the relative velocity would be Vr = V1 - V2 where V2 = (-V1).  So Vr = V1 -(-V1) = 2V.  But that would be 2c if V = c.  Because of Special Relativity this is not possible. The maximum speed at which they could separate would be c.  So the actual formula for relative velocity in special relativity is Vr = [v1 - v2]/[1 - (v1*v2/c2)] = 2v/[1 + v2/c2]. Using this formula you'll see the answer becomes just c(the speed of light).
Answer: Yes. Yes it absolutely can for any definition of velocity we would like to use.
Wait wait hang on Mr. VgAcid(lovely name I know), doesn't this contradict Einstein's theory of relativity? You look new what do you know?
Well, let us stepback. What is 'relative velocity'? Choose a frame for an observer: measure a physically established object's velocity. There you have it. The problem is... this depends upon your frame.
Now certainly, when it comes to inertial frames, nothing exceeds the speed of light.
But when it comes to accelerating frames, it does. In fact, the speed of light isn't even c!
Einstein himself mentioned this! To quote him,
"[...]But at the same time it turned out that one of the basic principles of that theory, namely, the principle of the constancy of the velocity of light, is valid only for space-time regions of constant gravitational potential" (Albert Einstein's paper "The Speed of Light and Statics of Gravitational Field", seen here: https://einsteinpapers.press.princeton.edu/vol4-trans/107)
[Uses is $c=1$ units]
In fact, we know names for coordinates of this: Rindler Coordinates. In this, $dx/dt=ax$ where a is the proper constant acceleration relative to an inertial frame.(evaluated here Does the speed of light vary in non-inertial frames?).
Or what about one of the most famous space-times, the Schwarzschild space-time? Let us choose Schwarzschild coordinates... then, we have $dr/dt =  1-2GM/r$(evaluated here How does the speed of light vary throughout a black hole?)
However, this is an artifact of our 'coordinates' if you want. But really, what else does measuring velocity amount too? You line up a ruler, find your object, tick the time. The only viable this can be done is locally. Now in THIS sense, can we only find that the speed of light can't be broken and that the speed of light is always c. But then it amounts less to a 'relative velocity' of some distant observer. The problem is that we can't cheat with free vectors like we do in both Galilean relativity and Special Relativity, and there in lies the problem. Velocity is not uniquely defined in General Relativity globally. In a curved space, when you try to 'transport' your vector, it depends on what path you take.
So after all this, we actually come to the conclusion that any sensible measurement of something that acts faster then light can't exist, since the only one that makes sense is the local measurement of light. So actually, relative velocity always less then the speed of light. At the expense of no globally applicable definition. You can try to use a more globally applicable definition of cosmological velocities with that of a 'proper distance' but you then get galaxies that can move at greater then light speed. Personally, I think the trade off is worth it.


Wifi - How does channel difference between transmitter and receiver affect the signal/data?

Question: When scanning a channel for wireless signals it is of course possible to pick up signals from surrounding channels. What I'm curious about (and forgive my n00b-ish-ness regarding the physics behind how signals are received/interpreted) is does picking up a signal from an adjacent channel affect any parts of the signal or data, such as the received signal strength measurement?
Answer: Signals from other channels are picked up as noise, lowering your signal-to-noise ratio (SNR). In principle, it could be picked up as data, but will almost always fail some very basic checks (correct preamble, destination MAC address, ...).
The channel mapping is built so 802.11b channels have sufficient distance to not influence each other. With 802.11g, the transmission bandwidth is wider, but the channel mapping was retained for compatibility purposes.
Interfering transmissions cause information to be lost, which is generally corrected for by a retransmission, decreasing efficiency of the system.
If any access points using the g protocol are around, it is generally best if everyone uses channels 1, 6 and 11 exclusively, as this avoids interference between adjacent channels, leaving only conflicts on the same channel, which the protocol is built to avoid even between different networks.
Comment: Discarded or ignored. The packet starts with a certain bit sequence to give the receiver an idea of the transmitter's clock rate, if that is distorted, data recording is never started. If the preamble looks valid, but the recipient address is neither our station address nor a multicast address, reception is terminated to conserve power, and the partial packet discarded. If the packet is received in full, but the checksum at the end does not match, the packet is discarded.
Comment: In order to find out which channel the packet was sent on, you'd have to look at the OFDM subchannels (WiFi uses many narrowband transmissions, digitally mixed to a single broadband channel), however I'm not aware of any implementation that will actually provide that information to the higher layers. The RSS is just a summary over multiple packet lengths, while the interferer you are looking for is most likely also using short bursts.
Comment: So what then happens to the data that fails the basic checks you mentioned? Is it dismissed? To give some context I'm specifically looking at monitoring beacon/probe packets, and trying to figure out the best way to sweep channels for their presence. I was hoping to find some correlation between RSS and channel difference to indicate which channel a transmission really came from without having to completely switch the receiver to that channel.


Is Earth's Surface "In orbit"?

Question: I'm having trouble understanding relative angular/tangential speeds at increasing altitudes above Earth's surface. In particular, I find this comparison of tangential velocities on Wikipedia very confusing. According to it, the tangential speed of Earth's surface (465.1 m/s) is different from the tangential speed required to "orbit" at Earth's surface (7.9 km/s). Why are these different values? My understanding of the Earth was always that material on and within the Earth is orbiting the center of the Earth just like satellties do. Time for multiple questions in one post...

Is material on Earth's surface not in free fall around Earth's center?
How are geostationary orbits even a thing? Seems like the only orbit that could be geostationary would be standing on the Earth's surface.
What changes as you orbit further above the Earth's surface? Does your angular speed increase or decrease? Does your tangential speed increase or decrease?
Is magma near the center of the Earth not rotating faster than material in the crust, like in an accretion disk?
Can two objects be orbiting (circularly) at the same altitude but with different tangential speeds?

Thanks in advance!
Comment: If we were in orbit, we'd be floating.
Comment: Consider what happens if you're standing at the North or South poles, and how you move relative to the centre of the Earth.
Comment: Consider that you can have celestial bodies that rotate pretty fast (Jupiter 9 hrs 56 minutes, Saturn = 10 hrs, 42 minutes) or pretty slowly (Venus 116 days, 18 hrs, Earth's moon 27 days, 8 hrs), irrespective of the speed needed to orbit them - which is a function of mass and distance.
Comment: *::blink::* I'd be interested in hearing how you came by the understanding that *"material on and within the Earth is orbiting the center of the Earth"*. No reputable source should say anything like that which leaves me wondering about plausible-sounding chains of conjecture.
Comment: As to #1, free fall is kinda the opposite of "being on Earth's surface". The former means **not** experiencing the forces associated with gravity, such as the force of your seat against your chair or your feet against the ground while standing. Even sky diving is not really "free fall" once air resistance builds up.
Comment: Consider that if Earth was rotating fast enough for you to be in orbit at the surface, then the surface itself would also not be held by gravity and the planet would throw itself apart - at least until the remaining surface was sufficiently below orbital velocity to remain stuck to the planet.
Comment: @dmckee I think my confusion came from descriptions of tidal forces (e.g., https://en.m.wikipedia.org/wiki/Tidal_force). They always show opposite "bulges" facing toward and away from the Moon, which I assumed was due to crust material being pushed into a higher, elliptical "orbit" by the Moon's gravity. I think I see now how the Earth's crust is not in orbit, but now I don't really understand tidal bulges lol
Comment: Earth's speed of rotation is simply not the required orbital speed. That's more a question of how much angular momentum Earth has left-over from its formation.
Comment: Oh, and let's not forget neutron stars, the fastest known of which spins at 43,000 RPM - which means the equator is moving at more than 20% of the speed of light.
Comment: It might be helpful to imagine the Earth as airless and *not spinning*. The orbital velocity at a given height around an airless, uniform body does not change whether the body is spinning or not, right?
Comment: If playing around with absurd scenarios like "an earth-mass planet spinning fast enough that objects on the surface are thrown into orbit", there is a mod to Kerbal Space Program that adds a planet like that to the game. I have not tried it myself but apparently it is quite difficult to land on.
Comment: The Moon provides a force of gravity on the Earth, the same as the Earth does on the Moon, and that force is stronger on the Moon side, and weaker on the opposite side. If it helps, think of the Moon as pulling the ocean on the near side away from the Earth, and pulling the Earth *away from the ocean* on the far side.
Comment: @PM2Ring Aren't we all orbiting the Sun?
Comment: @EricDuminil Fair point, although my solar orbit is slightly modified since I'm gravitationally attached to the Earth. But sure, Earth (and everything on it) is floating in freefall "above" the Sun.
Comment: If it did, we'd have flying cars for quite  a while already ;-). Also, we wouldn't need a space elevator (and couldn't build one; it would fly away).
Answer: 1. Is material on Earth's surface not in free fall around Earth's center?
No. Material on the Earth's surface -- or inside it -- is not in orbit, and so is not in free fall. You can temporarily put yourself into an orbit (and thus into free fall) by jumping up into the air, or jumping off a higher surface. When you do this, you are briefly in a very eccentric orbit (one which would take you very close to the center of the Earth, if the Earth wasn't a solid body) -- but then you hit the ground and are no longer in orbit.
The Earth rotates in the same way that a spinning top rotates; this has nothing to do with orbits.
2. How are geostationary orbits even a thing? Seems like the only orbit that could be geostationary would be standing on the Earth's surface.
Again, the surface of the Earth is not orbiting. The Earth rotates as a rigid body, with (as AtmosphericPrisonEscape noted) residual angular momentum left over from its formation, like a spinning top.
Because your angular speed in an orbit decreases the further away you are from the Earth, there will be a point where it happens to match the Earth's spin rate. If you arrange the orbit so it is above the equator and in the same direction as the Earth's spin, then you will always be above the point on the equator: a geostationary orbit.
3. What changes as you orbit further above the Earth's surface? Does your angular speed increase or decrease? Does your tangential speed increase or decrease?
Both your angular speed and your tangential speed decrease the further away you get. (Your angular speed would decrease even if your tangential speed stayed the same, because the circumference of your orbit increases with altitude; but in fact the tangential speed decreases as well.)
4. Is magma near the center of the Earth not rotating faster than material in the crust, like in an accretion disk?
The Earth rotates approximately as a rigid body, so in general, no. The molten outer core (which is not magma) may rotate slightly slower, while the solid inner core might rotate a little faster, but we're talking about $\sim 0.1$ degrees per year differences, and this has nothing to do with orbits. (The Earth is nothing like an accretion disk.)
5. Can two objects be orbiting (circularly) at the same altitude but with different tangential speeds?
Ignoring minor deviations due to things like the non-spherical nature of the Earth, mass concentrations in the crust, etc., the orbital speed for a circular orbit is a function of the altitude only. So two objects in circular orbit at the same altitude must have the same tangential speed. (Note that they can have different velocities, because velocity is a vector quantity -- so you can have two object orbiting in different -- even opposite -- directions at the same altitude, at least until they run into each other.)
Comment: "You can temporarily put yourself into an orbit (and thus into free fall) by jumping up into the air, or jumping off a higher surface...but then you hit the ground and are no longer in orbit." To paraphrase Douglas Adams, "The knack [to flying] lies in learning how to throw yourself at the ground and miss."
Comment: @JeffY You're using a more restricted definition of an orbit. In general, anything that follows geodesics is an orbit (or in Netwonian models, any trajectory curved mostly by gravity), and we usually allow for orbits that don't _perfectly_ follow geodesics too (e.g. satellites around Earth do not follow geodesics perfectly, because they're accelerated by their collisions with air). In the same sense, a person jumping off a cliff is imperfectly following a geodesic (until he hits the ground). The main point is that objects in orbits move exactly the same way regardless of how many orbits you do
Comment: Nice answer, but minor correction from geophysics: the Earth's Outer Core is molten (mostly made out of iron) and convecting according to magnetohydrodynamics, maybe(!) rotating slightly more slowly on average. The Earth's Inner Core consists (mostly) of solid iron and may be rotating slightly faster then the mantle/surface (but no more than 0.1 deg/year or so faster - with the years this estimated number went down substantially)
Comment: @JeffY Even in the two-body problem, there are hyperbolic orbits (like extrasolar comets!) which are not "cyclic". And more generally, there are chaotic orbits which are not cyclic, either. (As Luaan noted: geodesics!)
Comment: "5. Can two objects be orbiting (circularly) at the same altitude but with different tangential speeds?" Can't let that go without mentioning [horseshoe orbits](https://www.youtube.com/watch?v=gsHBE3DWCP4)
Comment: I think the idea that anything can be "in orbit" in Earth's atmosphere is at least confusing if not inaccurate. "Orbit" implies a cycle, and objects in low-earth orbit, e.g., are considered to be "de-orbiting" when they encounter the atmosphere at any significant density. And aircraft are not considered to be orbiting either (Star Trek dialog notwithstanding (Tomorrow is Yesterday).) In short, no vehicle has the thrust resources (nor the necessary heat shielding) to maintain orbital velocity in the atmosphere.
Comment: Again, it's highly confusing (read counterproductive) to include "any geodesic path" in the definition of "orbit", **especially when there is another perfectly good term** for describing such trajectories **as distinct** from orbits: ballistic. Alan Shepard was not the first American to orbit. Insisting otherwise is, frankly, divisive, crankish, and unnecessary.
Comment: @Rabadash8820 I added a link in the answer to #4 pointing to a Nat.Geo. article (which has links to the original papers) summarizing recent work on the core's rotation.
Comment: frederik -- Good points; I'll edit the answer.
Comment: @PeterErwin fantastic answer, marked as correct! If you get a minute, I'd love to see some links to back up your claims. E.g., the math behind #3 and where you (or rather @frederik) got the ~0.1 deg/year in #4 from. Thanks again either way!
Comment: Also @PeterErwin, regarding #5... What if a rocket was in orbit, and fired diagonally so that its acceleration had a tangential component _increasing_ its tangential speed, and a perpendicular component pushing back in toward Earth...could it not reach a faster tangential speed at the same altitude? I guess that isn't really true orbiting though...presumably once it turned off the engines, its tangential speed would send it up into a higher, elliptical, "true" orbit
Comment: @Rabadash8820 The rocket wouldn't be in free fall; you would feel acceleration onboard the rocket ship (in fact, the same as if you were standing on a surface - you basically made a very silly airplane). That's not an orbit. Being in orbit means you're following geodesics - your trajectory is curved only by gravity (to a reasonable approximation). The crucial point is that as soon as you turn off that engine, you're going to be on a highly eccentric orbit where your altitude when you turned off the engine is the lowest point, and the highest point depends on your velocity at that time.
Comment: @JeffY I've run into that frustration here over the term "orbit" as well - even the NASA website defines an orbit as "a regular, repeating path", and says that "all orbits are elliptical". A more general definition is given by Wikipedia, which is simply a "gravitationally curved trajectory". Most people use "orbit" as shorthand for "orbital trajectory" (which is repeating and elliptical), but it could also refer to a suborbital or escape trajectory (which are non-repeating and non-elliptical), particularly among such a precise and knowledgeable crowd as you'll find here.
Answer: Imagine you are in orbit around the earth, several 100 km upwards. What happens when you slow down? That's right, you fall down until some force stops your fall. That force is the pushback from the ground.
So next imagine: What happens when you throw a ball in the air? It falls back down to the ground. So it follows, that the ball is too slow to be in orbit.
Answer: An interesting corollary to this question: if the ground is not in orbit, how does it move (roughly) in a circle?  If we model a section of ground as an isolated particle, it's clear that in order to move in a circle despite having a relatively low tangential velocity, it would need to have an ongoing force being applied to counteract the direction the particle would 'like to go', following gravity.
Where does this force comes from?  It comes from the electromagnetic repulsion of the nearby material making up the rest of the Earth, which, having been around for a fairly long time, has largely stabilized to an equilibrium where the built-up compression counteracts the force of gravity, allowing material on the surface to move roughly in a circle, despite moving too slowly to be in a free-falling circular orbit.
Normally we think of the ground as 'stopping our fall', which it does, but it also continuously pushes us to keep following the path of the surface's rotation while we're in contact with it.  Fundamentally, electromagnetism is winning out over gravity, preventing our collapse and allowing us to move in a rotating frame without needing to orbit.
Comment: "it also continuously pushes us to follow the path of the surface's rotation while we're in contact with it" - this isn't really true. The material we were made from, and that our parents were made from, and that life itself was made from, was spinning long before we were around. We just have the momentum too - that's why jumping doesn't catapult you west.
Comment: Well, the residual momentum explains the part that has us moving in a rotating frame in the first place; the force from the Earth explains why that doesn't collapse due to gravity, despite that rotating frame not moving us fast enough to be in a free fall orbit
Comment: good point, though; I edited the wording to be a bit more precise
Answer:
I find this comparison of tangential velocities on Wikipedia very confusing.

…

According to it, the tangential speed of Earth's surface (465.1 m/s) is different from the tangential speed required to "orbit" at Earth's surface (7.9 km/s).

That might be, but they have explicitly elaborated "… Earth's own rotation at surface (for comparison— not an orbit) …"

Is Earth's Surface "In orbit"?


Does a cat behave like a dog if it is adopted with puppies when it is a kitten?

Question: As we know, the character of cats and dogs are different, for example, dogs usually follow their owners but cats usually not. But if a kitten is adopted with a group of puppies and grow up together, will it gain the character of dogs?
Comment: Anecdotally, I have a cat who was fostered with dogs; she swishes her tail when annoyed like a cat, and also when she's in a good mood like a dog. It confused my vet on her first visit, when she was purring while "wagging" her tail.
Answer: Yes and no. The cat will behave as much like a dog as a cat raised by humans behaves like a human.
It will learn how to read canine body language and noises, and figure out how to start and stop play, and the other essentials for living with the dogs. It will probably think of the dogs as big confused cats, just as it will think of the humans in the household as big confused cats. (Dogs think they're inferior humans; cats think we are inferior cats.)
So the cat may adopt some habits and tricks to get along with the dogs better. It will certainly consider the dogs good warm things for sleeping with and on. But it will remain essentally a cat; a lot of the basic behavior is built in. (A lot of ours is too, but we combine training the ape to follow directions and making up justifications for behaviors the ape does on its own.)
A friend of mine had a dog that had a pet cat. That was clearly the relationship; the cat spent more time with the dog than with the human, and the dog would carry the cat around as if it was a puppy or toy. But outside of that friendship, and always smelling like dog drool from being carried and washed all day, the cat was a cat.
Answer: I have a cat that was raised with two dogs. She plays like a dog, and chases her tail like a dog. She also has trouble socializing with our two other cats. The cat belonged to my parents, and  we took her in when my dad could no longer care for her.
Answer: I have a cat who was raised by my dog since he was five weeks old.  Delilah nursed him, bathed him, cleaned his bottom, let him eat first - just like he was her puppy. (She is spayed so she only has this adopted child.) Blue behaves like a dog in many ways.  He follows his people like a dog does.  He sleeps on people beds every night, even though he is an indoor-outdoor cat.  He grooms his dog-Mama's face!  They regularly bump noses. Blue is now three-and-a-half.  Still a puppy to Delilah.


Simulate Step down chopper circuit using any Electrical Engineering software

Question:
Here's my attempt:

Could someone tell me where is my mistake ? Or simulate answer the question using any other software,please ?
Answer: The modulation index refers to that sawtooth waveform you have as an input, which is meant to be compared with a 741 (no comment), giving you a PWM output. Thus, your source is not an FM modulated sine, but a sawtooth, with PULSE(). I'll let you calculate your values, but I'll hint about the rise time that can be equal to the period, while fall time and period can be zero.
I can't quite tell if the source needs to be repeating, or not, but even if it's not, PULSE() or PWL() work just fine.
Since the request behind the scenes is to see if you're able to give proper waveforms, then you can choose some models from the internal library (2N5550 is as good as any). Don't forget to set the voltage to the value in the picture.
As a side comment, you can also eliminate R1, R2, and the two voltage sources connected to them, and keep only one source with the proper level that needs to be either .stepped, or dynamically adjusted (PULSE(), or PWL(), or...).


In Adwords is it possible show ads during particular times for multiple time zones

Question: Is it possible to have a campaign covering lots of countries / lots of different time zones, and to have ads showing only during particular times of day as per those time zones -- for example between 9a and 5p for each time zone?
Answer: Seems that this is possible:

Ad Scheduling
Ad Scheduling (also known as "day parting") lets you tell Google exactly when you want your ads to run, and more importantly, when you do not want them to run. In addition, more advanced users can automatically modify their bids based on time-of-day and day-of-week cycles in campaign performance.
Ad Scheduling can help you with improving ROI for your display campaigns by ensuring that your ads show at times where it performs the best. For example, if you notice that you are getting the most conversions from Monday to Friday and nothing on Saturday and Sunday, you can schedule your ads to appear only during those times so that you are maximizing your ad's performance with your given budget.

It also says "You can set an ad schedule for particular hours of the day, or specific days of the week", so this looks like what you want. Still might be a fair bit of work to set up, of course...
Comment: it looks like the time setting applies to my timezone only. as far as i can gather i don't think there's a way to deal with showing ads at different times of days for multiple timezones in one campaign, other than adding countries in and taking them back out again at different times of day
Comment: This takes a few seconds to set up. But I need this to apply to timezones. I'm in the GMT timezone, so if I set times, do they apply to my timezone only? If I set 9am to 5pm as the times my ads show, do they show at 9am to 5pm in the timezone GMT-7 or do they show in the GMT-7 timezone at 9am to 5pm as per GMT time?
Comment: I suspect you would have to ask on the Google Adwords support forums to find that out (or try it and see what happens).. but if you do, can you come back and edit this answer to let us know?


How to mark an ant with the least disturbance to the ant and the nest

Question: How would one go about marking one or more ants in a nest so as to least disturb the ant and the nest? The goal is to be able to know which ant you marked months, or many years up to a lifespan later, while at the same time have the least influence of the markings on the behavior of the ant and the interaction between the marked and not-marked ants.
Comment: lots of previous research has been done marking bees and ants.
Answer: For this purpose, people usually paint ants on top of the thorax (not on the head where it can prevent eyes and antenna to function normally, nor on the abdomen where it can block the spiracles and prevent respiration), with a bit of acrylic paint applied with a toothpick. Combination of colors are used to identify individuals.
These techniques are currently being replaced by the use of RFID tags and Flashcodes in science, to automate recordings.


What is different between Magento 2.3.5-p1 and 2.3.5 version?

Question: I upgraded Magento 2.3.4 to 2.3.5. But Magento site https://magento.com/tech-resources/download is available version 2.3.5-p1? Something different with versions 2.3.5 and 2.3.5-p1? I want to know that is there any difference between both versions which one I need to update on the store ?
Comment: you've accepted the wrong answer, fyi
Comment: it's not wrong ... its correct ... if u have any more details or more specific answer then please add here so it will help to someone
Comment: See the comment I added to the accepted answer
Answer: The p1 suffix denotes the full release for the quarterly update and contains further fixes to a unique error. Generally if you're not experiencing errors I don't think you need to upgrade to p1, though I would take a look at p2 as this update is security related;
https://devdocs.magento.com/guides/v2.3/release-notes/release-notes-2-3-5-open-source.html
Answer: A while ago Magento changed their release process to include security-only releases (https://community.magento.com/t5/Magento-DevBlog/Introducing-the-New-Security-only-Patch-Release/ba-p/141287?_ga=2.215616274.442714052.1591948834-51687988.1567676784). The version 2.3.5-p1 should be one such release.
For security issues, these are highlighted on the Adobe Security Bulletin and it seems for this patch we are looking at https://helpx.adobe.com/security/products/magento/apsb20-22.html and you can see the vulnerability details at https://helpx.adobe.com/security/products/magento/apsb20-22.html#Vulnerabilitydetails
Using github you can do a compare of the two tags 2.3.5 and 2.3.5-p1 https://github.com/magento/magento2/compare/2.3.5...2.3.5-p1
With this overview you can see that there is only one commit difference between the two versions (https://github.com/magento/magento2/commit/13c18d0b3f2e3fa53b317db5452eaab3d28dbeca).
Comment: This is incorrect. From the magento website: "During pre-release, we discovered issues that forced us to create new packages. To expedite delivery, we chose to change the name of the full-release patch from 2.3.5 to 2.3.5-p1. The 2.3.5-p1 package contains all new features and fixes. We also changed the name of the security-only patch for this quarter from 2.3.4-p1 to 2.3.4-p2. Future releases will follow the typical package naming conventions for full-release and security packages."


After copying files from mac to pc and back to mac, my .xcodeproj file is showing up as a folder

Question: How can I get this back to a "file" I can open with xcode?
Answer: There may well be a better way, but you can convince OSX to make the change by first renaming it to something without an extension (myProject.xcodeproj becomes myProject), then renaming again, adding the extension back in (myProject becomes myProject.xcodeproj).
I just tried it and it seems to work fine.
Comment: Thanks, was worried there! :)
Answer: Because HFS filesystems hold a lot more metadata than most others, including FAT and NTFS, copying entire branches, e.g. folders of files, onto other filesystems tends to lose stuff like the bundle state.
Different copy methods also have different copy results, depending on whether the invisible files are picked up by the copy.
The best way to address this is by either compressing the whole branch before moving it off HFS, or by keeping the branch on a virtual disk that you mount from your mac as needed.


When walking, why the foot which get the reaction doesn't accelerate?

Question: To walk we apply a force and the earth gives us a reaction. But the foot which get the force doesn't accelerate.
Answer: You can think of it this way: when you step forward, your body pushes backwards on your foot, I.e. accelerates it, but the ground pushes it forward (via friction) and the net acceleration of the foot is zero. Meanwhile, the equal and opposite reaction when your body pushes backwards on your foot is that your foot pushes forward on your body, so there is a net forward acceleration of your body. As well, nothing counteracts your foot's backward push on the ground, so the ground moves backwards because there is a net acceleration: but we tend to ignore that, because the ground is a massive planet and doesn't accelerate much from our human-sized forces.
Answer: Walking is arrested falling. That is, we use the planted foot to lean forward and use the acceleration of gravity to begin a fall. Then we move the other foot forward to arrest the fall. This now becomes the planted foot and we continue.
Answer: The foot which gets the force is connected to the leg and the rest of the body*. Force applied to the foot is transmitted to the rest of the body. Furthermore, the force applied (by the earth) is a frictional force, and opposes any motion of the foot. In cases of low friction (walking on ice, for instance) the food does indeed move. The active force applied to the foot comes from the mass of the body and gravity.
*To quote the song: "Oh, the foot bone's connected to the ankle bone, the ankle bone's connected to the shin bone, the shin bone's connected to the knee bone, the knee bone's connected to the thigh bone, the thigh bone's connected to the hip bone, the hip bone's connected to the back bone, the back bone's connected to the neck bone, the neck bone's connected to the head bone. Now hear the word of the Lord."


How does an ASA view packets coming from a remote site-to-site peer? As inside or outside?

Question: I'm trying to test ACL's coming inbound from a remote peer site (using packet-tracer) (IPSec site to site VPN) and I wanted to know what interfaces ACL's are checked in this case and which interface I use for packet-tracer command?
If incoming IP's are coming in over a site-to-site tunnel do they hit the inside interface's ACL's? Thanks in advance!
Comment: As long as you're attaching the ACLs in the right place, yes.
Comment: Are you asking about the encapsulating packets with an IP type of GRE or ESP, or the packets that have been decrypted and are ready to route to the local site?
Comment: I'm asking: if I have host A behind an ASA at one side, and host B behind another ASA at a remote site, both sites have an ipsec site to site VPN tunnel between them.. if I were to accurately test ACL's to and from host A to B and vice versa, how would I do this with packet tracer? would I use: packet-tracer input INSIDE in both directions? or use packet-tracer input INSIDE for one way and packet-tracer input OUTSIDE for the other way?
Comment: If I understand your question correctly, you'd use `inside` on both ends. The tunnel endpoint interface is logically on the inside.
Comment: Ok, and that's what I thought, but it does pass physically through the outside interface so I wasn't sure if traffic would bypass the access-lists on the outside interface, or how that worked and the impact it would have on packet-tracer .. tracing?  Please confirm to test traffic in both directions using pcket-tracer input INSIDE for both directions is correct!  Tysm :)
Comment: There's a virtual "wormhole" at the edge of the tunnel. The tunnel interface is in some zone, but packets entering it get magically packaged up and delivered (inside new GRE or ESP packets with completely different headers) to another endpoint, where they're unwrapped and pop out magically from another tunnel interface. Conceptually, pretend that the two tunnel interfaces are just like a pair of Ethernet ports with a wire between them.
Comment: Ok, so as far as processing and ACL's go, it's functionally like INSIDE to INSIDE traffic?
Comment: Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
Answer: They originate on the outside interface. This is one of my NAT entries for an international site connected via L2L:
nat (inside-office,ISPA) source static Corporate Corporate destination static France France no-proxy-arp route-lookup

ISPA -> translates to outside for most people, 0 security interface
Corporate -> object-group network containing the local/MPLS subnets
France -> object-group network containing the remote site subnets
This applies to the ACLs as well. However you will need to use:
no sysopt connection permit-vpn

Otherwise the VPN traffic will bypass the ACLs.
However you can use a VPN filter instead of placing ACLs on the interface and avoid turning off the sys opt connection permit-vpn option.
Example may be found here: http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_configuration_example09186a00808c9a87.shtml#configs
Comment: Ty for your help, I haven't had time to digest this yet, but I will mark answered once I have time to read through what you've posted!
Comment: No worries. Personally I use the VPN filter for my networks. Less ACL maintenance as you don't have to mess with any interface ACLs.


Completely...I mean COMPLETELY wiping my hardrive

Question: I am new to linux, a total noob to be exact. I am using ubuntu 14.04.2 I am having a problem with people at school who have somehow hacked my computer. I have formatted my hard drive 3 or 4 times already but whatever they have put on here will not get erased. In fact this is the reason I switched from windows to linux. I thought that whatever exploit they used was windows based. Somehow they are able to monitor my activities in real time, even when I am not connected to a network. I have even tried disabling networking but it is no use. I constantly hear them making comments about what I am doing and it is driving me crazy. Help please!
Comment: If you have unplugged the network, then it isn't coming from your computer.  They must have a spy cam in your dorm room or something.
Comment: Without networking, no one can see what you're doing. How do you know they are seeing what you do? Are they telling you?
Comment: @Destro Have you enabled sharing your workspace ? or they have done ?
Comment: I agree with psusi. If you sill want to wipe your hard drive though, first boot from Live Media and then follow http://askubuntu.com/a/17650/205638
Comment: @Zacharee1, Well I hear them when we are in lab. its a relatively small lab. I hear them commenting on every little mistake I make. Sometimes I make mistakes on purpose to hear if they are still watching. When I am on the network I know they can see. It's how they see what I am doing when I am offline that really kicks me.
Comment: That's just them watching behind your back. It's impossible to monitor what you're doing without having network access.
Comment: If you disable network they can't see what you are doing. They probably messing with you. Saying stupid stories to see your reaction and on what story will you "fall".
Comment: possible duplicate of [How can I securely erase a hard drive?](http://askubuntu.com/questions/17640/how-can-i-securely-erase-a-hard-drive)
Answer: It is literally impossible for them to be monitoring your computer screen via the OS in real-time if you are not connected to the network. I go through some possibilities below.
Delayed Logging
They could be logging everything to a file somewhere on the computer and then uploading the log when the computer returns to the network. This is the common practice with keyloggers.
If they are making comments in real time this cannot be the case.
You are Still Connected
You could still be connected to the network even though you think you aren't. Perhaps you only disconnected ethernet but are still connected on wifi. Or perhaps they have hijacked your network manager to always stay connected. You can make sure this isn't the case by physically disconnecting your ethernet cable and wifi card.
This is very unlikely since you said the problem persisted from Windows to Linux. Assuming they have infected your computer with some virus, the hack must be below the operating system, and thus running at a privilege higher than the kernel. If this is the case, you are dealing with pro hackers, and "wiping" the hard drive might not remove the hack; depending on the attack vector they could have told the hard drive never to overwrite those sectors.
Button Camera
They could have a spy camera somewhere watching what you do.
Check your laptop, work area, and person thoroughly for anything resembling a camera. Also try covering different areas with paper to see if this stops them.
Direct Observation
Someone could be looking over your shoulder.
This could be the most likely option. It sounds like you are in a rather small work area. Perhaps someone is simply looking directly at your screen.
Comment: ok I see. If they do have something installed on my computer, would it appear on the system logs?


Adobe Indesign: How to measure the width of a word?

Question: Is it possible to measure the width of a word in some way? (via Javascript code, or a built-in software option)?
Answer: The only way I know is to:

Create a text frame. (Make sure that it has basic appearance without insets.)
Paste the word you want to measure into the text frame.
Press Ctrl / Cmd + Alt + C to Fit Frame to Content.
Read the width in the Transform panel.

This width includes a tiny space before and after the word which comes from the way the font was designed. If you want the exact width of the geometric shapes, use Type > Create Outlines instead of Fit Frame to Content.
Although a little hacky, this method can also be used in a script in the exact same way.
Answer: Easy way to do this would be to simply draw a line or box and take the measurements from the chosen rule of the line or box.
I'm sure an InDesign whizz will know a plugin for a rule, however this is my quick fix.


sRGB and AdobeRGB color spaces

Question: They say that AdobeRGB has more colors than sRGB color space.
What do they mean? Should they both have  16,777,216 colors (because they're both RGB color spaces)??
Answer: Adobe RGB also tends to be more red-ish, it's often used when printing stuff, sRGB is more common in the digital world with monitors and digital-media. They are different color-spaces, how many values they can represent it's something that is implementation-dependant, it's not the main difference between them.
In the color-world there are color-models and color-spaces, this 2 are both RGBs so they belong to the RGB color-model family but they are 2 different color-spaces.
The difference here is about how the arrange color values in the space and based on what, to really understand this you should study how a printer works from a color standpoint and how a display works.
It's like how the Mp3 compression works, you have an uncompressed audio source, you want to compress it or in other terms, to represent only the most significant Hz, so you need to make a choice AND you need to give an algorithm, a rule; in the Mp3 case the rule is simply what Hz the human ear can catch easier than others, you discard all the ininfluent or unheard Hz and you only keep the most important ones. In the RGB case you don't have audio but you got colors, you don't have Hz/waves but color-values/hues, and you always got a finite space, meaning that you need to make a choice because you can't store infinite values, so you basically make a choice based on what are the studies behind this 2 color spaces and in a nutshell the AdobeRGB is best for printing and sRGB is for TV, monitors and everything similar. To undestand how they works just read the papers, it's impossible to explain this in a short answer but there are many resources around the web.
Answer: Check out this article http://www.kenrockwell.com/tech/adobe-rgb.htm which basically says that they both occupy the same range, but due to software the Adobe RGB can be unpacked and then further expanded.

Adobe RGB theoretically can represent a wider range (gamut) of colors,
  however:
1.) Adobe RGB requires special software and painstaking workflow not to screw it up. Make one mistake anyplace and you get dull colors, or
  worse. You cannot use Adobe RGB on the internet or for email or
  conventional photo lab printing. If you do, the colors are duller

Further reading about the 2:

sRGB is a RGB color space proposed by HP and Microsoft because it
  approximates the color gamut of the most common computer display
  devices. Since sRGB serves as a "best guess" for how another person's
  monitor produces color, it has become the standard color space for
  displaying images on the internet. sRGB's color gamut encompasses just
  35% of the visible colors specified by CIE (see section on color
  spaces). Although sRGB results in one of the narrowest gamuts of any
  working space, sRGB's gamut is still considered broad enough for most
  color applications.
Adobe RGB 1998 was designed (by Adobe Systems, Inc.) to encompass most
  of the colors achievable on CMYK printers, but by using only RGB
  primary colors on a device such as your computer display. The Adobe
  RGB 1998 space encompasses roughly 50% of the visible colors specified
  by CIE — improving upon sRGB's gamut primarily in cyan-greens.

Source
So, it would appear that the colours available to RGB is much greater than what is offered by either sRGB or Adobe RGB and that Adobe applies a compression technique as well as choosing to select a different range of colours (compared to sRGB).

sRGB and AdobeRGB color spaces