Why isn't my quill stem controlling the front wheel of my bike?

Question: Please excuse me if some of my terminology is off. I don't know much about bikes.
When I came home from college I noticed that the seat of my bike was way to high and the headset was really low, I have a old style quil stem head set,. So I decided to raise the headset. When I raised the headset I did not know that I was not supposed to completely remove the headset stem bolt. I tried screwing it back in but it doesn't work. So now the headset does not control the front wheel, and I have no idea how to fix it. Can someone PLEASE help me!!! I also have a question, why is it that when I hit the bicycle stem bolt with a hammer it fixes it but only for a short time period?
Comment: Duplicate of  http://bicycles.stackexchange.com/q/21360/14414
Comment: I just have one more question. Why is it that when I hit the bicycle stem bolt with a hammer it fixes it but only for a short time period?
Comment: You mean hitting the quill with a hammer?
Comment: I'm hitting the stem where the stem bolt is that connects the headset to the wheel.
Comment: wild guess: you deformed the quill by hitting it with a hammer. This (small) deformation is enough to hold the quill in place within the (fork) steerer tube. But not strong enough to permanently fix the quill in the steerer tube
Answer:
Completely remove the bicycle quill
Hang the bike up-side down
Take out the wedge. If the wedge is stuck, try inserting the quill bolt alone (no quill, just bolt). Take care not to push the wedge further in. Try to thread in the wedge, and remove the wedge when there is enough grip.
If wedge is truly stuck, remove the front wheel from the fork. The fork should have a hole so that you can push the wedge from below (with rod/hammer)
Re-assemble the quill and wedge with the bolt correctly. Make sure you know how to do this, it should be straight-forward.

Good luck
Bicycle terminology (regarding quill stem, which often seen in old bicycle):

Wedge (sometimes 'Expander'): a device that wedge/expand the quill inside the fork steerer tube. This is achieved via compression of the wedge/expander into the quill, using a quill bolt.
Quill: a device connecting (fork) steerer tube and stem. Usually the stem and the quill comes together as one part.
Stem: a device connecting the handlebar to the fork (via quill).


What is this white tuber on my cactus?

Question: Yesterday I noticed that my cactus had a white tuber type thing growing out of it. Is this normal? It's almost doubled in length in the past 36 hours.
Comment: Looks like a root. Is that a flower bud opposite it?
Answer: It's an adventitious root. I think that's a Hylocereus which is an epiphytic plant (grows on other plants). It's native to the jungles/rain forests of central america.
I recommend cutting both offsets off and planting them in some cactus soil. That's if you want three cactus instead of one. You can leave them, but the new shoots will take energy away from the graft (the red part).
You have a Gymnocalycium (scion) grafted onto the Hylocereus (stock). The Hylocereus provides photosynthesis services to the Gymnocalycium. The Gymno can't photosynthesize because it has been modified/bred to not have any chloroplasts. The red is what's left when you take the green away.
Comment: The offsets will flower but they need to grow to 4 feet or more. They will grow to many tens of feet. They have huge flowers and some will make "Dragon fruit". Glad you found the info useful.
Comment: Thanks, that answers a lot of questions. I wasn't sure if the offsets would "flower"as well. Didn't know it was a graft.
Answer: Woah! That looks like a root, right? Not sure why it'd want to shoot off a root from there, unless maybe the junction to the main plant is compromised?
Comment: No idea. The main plant should be fine as far as I know, it's never taken any damage.
Comment: Hi Hanktus, sorry but you have not answered the question, can add more details on what it is?

What is this white tuber on my cactus?


Why is the value of volume charge density $ρ$ zero in lossy medium?

Question: Given is the page of a book which I was studying. I was trying to study the derivation of the wave equation in a lossy medium. As I have underlined a sentence that says, "most of the case in which wave is propagating does not contain the charges". Why is it so?
Answer: This is not true in all cases, but at least approximately valid in most lossy media. Note that even if $\rho\ne0$, it is only the gradient of the charge density ($\vec\nabla\rho$) that appears in the wave equation, so the wave propagation is unaffected by a uniform non-zero charge density. Even if $\rho\ne0$, its gradient is usually (but not always) small.
A lossy medium has non-zero conductivity, meaning charge carriers can get redistributed. For example, if at some point in time there is a large amount of charge localized in a region, the resulting electric field can quickly cause this charge to redistribute, until a zero charge density is reached.
Again, there are lots of counter examples, such as a pn-junction.


How to embed OpenSocial Gadget

Question: I have a gadget in Jira dashboard.
Could anyone clearly and simply explain how I can display the gadget on my html page?
Answer: If you want to show a Jira gadget on your own html page, your site must be an OpenSocial container. Try downloading and running the reference container Apache Shindig.
If you want to use gadgets that access protected resources (like "My Activity"), then you will also need to implement OAuth consumer features to consume resources on your Jira server (the OAuth producer). I can't remember right now if there's a working consumer implementation out of the box. Register your website as an external application on Jira, setup the proper consumer keys and you should be good to go.

How to embed OpenSocial Gadget


Spread SQL Server data files across devices to improve performance?

Question: Would it improve performance of a database in SQL Server if I place the .mdf (rows data) and .ldf (log) files on separate sets of raided disks, as opposed to having both files on the same set of raided disks?
Comment: **As a sidenote:** I hope you have some kind of clustering or another replica of your server running in sync.By keeping logs and data on the same RAID volume you would not be able to recover to the point in time of the failure.
Answer: All performance solutions are based on measurements. As the theory goes, SQL Server requires the transactions to flush to durable storage (disk) before acknowledging commit (WAL). This makes the log write throughput critical for high write loads. Separating the LDF file on a separate physical disk allows the log writes to achieve serial streaming access to disk, which is the fastest way a spinning disk can write (~100-150Mb/s). Having the MDFs on the same physical disk introduces random IO patterns that dramatically reduce the throughput (~10-40Mb/s). This is the background of the separate LDF /MDF disk recommendations. The point is, obviously, mute on SSD storage.
However, to improve the server performance you need to identify the bottleneck and address it appropriately. If your bottleneck is poor indexing, lock contention, CPU, small buffer pool or any other of many more possible causes then separating the LDF and MDF will help nothing. So you should first find the bottlenecks, and I recommend following the Waits and Queues methodology. Once you have measurements that prove a bottleneck that causes performance degradation then and only then you can act appropriately.
Comment: Good answer. I just want to underscore for the OP that this applies to a **single** database. If there are log files from multiple active databases, that's random access, not sequential.
Answer: Short answer: yes for write heavy loads, but the difference is not always as significant as people expect.
You are most likely to see measurable improvement during periods of high write activity, as updates/inserts result in changes to both the transaction log and the data files so if they are on the same physical disks there will be more head movements to services these write operations. SQL Server does try to bunch writes to the log and data files though, so you might not see any difference for some write loads.
We keep out log files on separate volumes because for some load patterns our application sees it does make quite a difference - but you should run tests to see if it is applicable to your application. You may find the difference so small as to not be worth bothering, and you might find other tricks (partitioning the data over the multiple volumes perhaps) give you better results.
Answer: Short answer is yes. The bigger and busier the database the more this helps.
Very simplified explanation is this: you have .mdf file that sql server service reads and it writes to and you have .ldf file that is in most cases only used to write data.
This means you have read/write for MDF and mostly write for LDF and the fact that hard drives can only do one operation at a time.
In reality this is more complex but this is oversimplified reason on why this helps.
Here are two good articles on this topic
http://technet.microsoft.com/en-us/library/cc966534.aspx
http://www.codeproject.com/Articles/43629/Top-10-steps-to-optimize-data-access-in-SQL-Server
Comment: To clarify: traffic to data files is mostly random reads with burst writing during checkpoint operations; traffic to log files is mostly sequential writes. Imagine the work that one disk read/write head has to do to satisfy both operations. So, general practice is data and log files on different spindles. However, as several posters here point out, this is "general" advice - YMMV.
Answer: Well, it helps with I/O performance, although you won't see a huge performance increase.
That is the real problem with Relational Databases. That's why there are No-SQL databases (MongoDb) that address the performance issues
Comment: -1 [Not even wrong](http://en.wikipedia.org/wiki/Not_even_wrong).


Moving an encrypted home folder to a new drive

Question: Is there something I should be taking in to account when moving an encrypted home directory to a new drive? Is it just enough to rsync the contents away, edit fstab etc?
Answer: What I would do:

Be sure to have no user logged when doing the copy, so that encrypted directories are not mounted.
Copy the whole /home/, as there is a /home/.ecryptfs which I think contains all the encrypted data.
As root, run rsync -av /home/ /other/disk/home/ in order to preserve all file attributes.
Comment: In the end I tried to remove the encryption and then just move and re-enable the encryption. Which didn't go so well so I just reinstalled Ubuntu and used a backup. One thing which I wasn't so sure was that the encryptfs makes a hidden mount (if I'm correct), wasn't sure if just moving all the files would be enough.


Is it safe to auto-login if the system is encrypted?

Question: I'm running linux (specifically Debian 9) on my everyday-use laptop, where the disk with the system is encrypted, so whenever I boot it up, the password is required prior to entering the system. In this case, is it safe to setup getty to automatically log in a user with root privileges (sudoer, while sudo does not require password)? Is there any way a potential attacker might get into the system?
Answer: Encryption means attacker can't access and modify your data (when the computer is not used – decrypted). If you log in, you must have physical access to computer to access data (attacker can read everything because sudo).
There is no way for attacker to get to the system if you lock it using some program like vlock.
Answer: In principle, since data can only be read once the disk has been unlocked, regardless of whether the user is automatically logged in or not, auto-login will have next to no effect on security since the user has already been authenticated at boot.
This assumes that the computer is shutdown properly, the encryption password is not shared, the password is long enough, etc... Disk encryption best practices are taken.
Answer:
Is there any way a potential attacker might get into the system?

The Cold Boot Attack:

attacker with physical access to a computer is able to retrieve encryption keys from a running operating system after using a cold reboot to restart the machine

New Cold Boot Attack Unlocks Disk Encryption On Nearly All Modern PCs

If you are connected to the internet an encrypted system is still
vulnerable to the network attack.


Database Object That Reads From Two Tables and Writes to One

Question: I am updating a database design that must be compatible with old and new applications. My goal is to make a design change which minimizes impact on the existing code.
The Design Change
Currently our database has universal data that is stored in each customer database. I want to move this common data out to a different DB/server to make maintenance easier. However, I also need to retain a local copy of these tables so customers can add and edit custom items (which we will not be responsible for maintaining).
What to Use?
So basically I need selects to return data from both tables and update/delete/insert statements to modify data from the local table.
I think I can use a view to return data from both of the tables as an aggregate, but is it possible to set it up to write to only the local table?
I'm using SQL Server 2008 with VB.NET.
Comment: This doesn't sound like good design to me.  Your SELECT and UPDATE statements need to reflect what's actually happening, not hide some magic functionality.  If you really want to do this, *write a stored procedure* that does it.  That way your intent becomes crystal clear.
Comment: See also [Views](https://en.wikipedia.org/wiki/View_(SQL)#Read-only_vs._updatable_views), and [CREATE VIEW (Transact-SQL)...Updateable Views](https://technet.microsoft.com/en-us/library/ms187956(v=sql.105).aspx), and [Designing INSTEAD OF Triggers](https://technet.microsoft.com/en-us/library/ms175521(v=sql.105).aspx)
Answer: Yes, you can use views to obtain an aggregate representation of rows from two (or more) tables.  On the other hand, as you seem to already realize, views are not normally writable.  Even if MSSQL (or any other RDBMS) offers some magic features to write to a view, I would advise against using them, because magic tends to turn and bite you in the end.  (Magic works very nicely until it doesn't.  And it makes it very difficult to understand what is going on.)
The vast majority of database operations performed by any application are reads, so you can cover those with views.  For the remaining very small percentage of operations that are writes, just do it the straightforward way and modify the code to write to the right tables that are meant to be written.
However, keep in mind that breaking a database down into separate databases is hardly ever a good idea, because transactionality and referential integrity are usually lost when you do that.  Are you sure what you need cannot be accomplished by adding one more column which identifies whether a given row belongs to a specific customer or to the universe?
Comment: I want to break the database up so that we can easily maintain the common entries. Otherwise we will be running update scripts on hundreds of customer databases


Update Panel not working in Firefox 2013

Question: Update Panel is not working in SharePoint 2013. It is working in SP2010.
In Internet Explorer, it is working fine but in Firefox, the page is refreshed.
Answer: There appears to be some sort of change in the postback mechanism that's used by SharePoint and ASP.NET in SP2013.
Here's a solution provided on MSDN

In Visual Studio, add a reference to Microsoft.Practices.SPG.AJAXSupport.dll. Add a SafeScriptManager control to your page and set the EnableUpdatePanelSupport flag to true. This changes the postback script that is needed for the UpdatePanel control to work in a SharePoint environment. The following code demonstrates how to add a SafeScriptManager control to a page.
Comment: Can anyone help me to find this Microsoft.Practices.SPG.AJAXSupport.dll . Am struggling to resolve the Sharepoint Updatepanel issue
Comment: This solution is not work on SharePoint 2013. Solution probably for SharePoint 2007


HOTP/similar - how about standard backups of mobile devices?

Question: I was considering adding HOTP as an option to my website (alongside things such as SMSed one time tokens which I already have). But I was considering one issue that HOTP inherently has:
Things such as the iPhone usually get backed up along with all app data. That would mean, say I'm using Authy to generate my OTP tokens, the secret keys from within Authy would get included in such backups as well. Well, the entire purpose of OTP is so that information on the computer is not enough to break into an account and you need that second factor just in case something such as malware gets onto the computer (if I understood properly). But this backup means, if I have access to your computer, I can get your password through conventional manners such as a keylogger, but I can also look through your mobile phone backups for the HOTP secret key and without your phone, successfully log in.
So what's keeping people from doing that, and why should I also offer HOTP or is it better for me to still just stick with only SMSed tokens?
Answer: Some phones send SMS messages to a computer in realtime when nearby it (Samsung has a little thing for their android phones that does this, or did), and if the phone is plugged into a computer and supporting Hayes modem commands, those can read text messages in realtime too.
Really, what OTPs get you is protection against people guessing passwords, though they are sometimes helpful with stolen ones too.  That said, TOTP would be better for this given that it is ephemeral and thus the chances of getting it right don't increase as the number of attempts do.  The HOTP is really not much better than a password consisting of the key and counter (in my opinion), except that it effectively comes with its own challenge auth for anti-replayability.
If you need to be secure against people stealing the tokens from phone backups or whatever, you really should issue hardware tokens.
Answer: SMS and and smartphone apps are vulnerable to different attacks. I would not call SMS a secure method to transport a one-time password. As Falcon was pointing out: If you really want to do two-factor authentication (2FA), you should use a second factor that cannot be sniffed and cannot be copied. The first is not valid for SMS and the second is not valid for smartphone apps. So, for a real 2FA you really shouldn't use a connected piece of hardware.
But nevertheless, security is shades of grey. So sending an SMS or using a smartphone app (no matter if HOTP, TOTP or mOTP) in addition to the password, is better than only having the password. You just need to be aware of "how much better" it is.
Having a smartphone app has some advantages over sending SMS:

you do not have any SMS costs
you will be also able to authenticate, even if you have no GSM service (like in datacenters with big walls or under the earth).

Ofcourse SMS provides an easier registration process for the end-user than installing an mobile app and sharing the HMAC-key with the server.
So providing HOTP and SMS is primarily a convenience for the end-user.


How useful were Chinese contributions to the defeat of Japan in WWII?

Question: While there is no doubt China contributed a lot of blood and treasure in the War with Japan, how useful were those contributions given that Japan was strangled by a the navy, bombed by the air force and finally hit with nuclear weapons all of which were delivered from the Pacific? It has been said that China tied down a lot of Japanese troops, but would those troops have made much difference given that you can only pack so many defenders onto an island and you have to have ships to move the men around? If China had fought twice as effectively or half as effectively how much difference would it have made to the outcome of the war and to the military expenditures of America and other western allies in the Pacific?
Comment: What would have happened had the US never become involved and Japan had never signed a pact with the Axis countries?  Japan had already spent over a decade fighting in China and were not approaching a peaceful equilibrium of domination.  There were well respected voices in Japan arguing for a diplomatic solution in China and rollback of military activity.  But the prospect of the humiliation of defeat caused the militarists to "surge" internally in Japan, leading to a string of political assassinations and an atmosphere of fear and intimidation where common sense no longer ruled the country.
Comment: "China's fight supported the anti-Fascist struggle in the European and Pacific theaters, disrupted the overall plan of Japanese ... thwarted Japan's "northern march" plot to invade the Soviet Union, &  delayed its "southern march" schedule for unleashing the Pacific war ... **67 percent of the total Japanese military strength was tied up in China during the most dangerous period of the Pacific war** - [**article**](http://www.chinadaily.com.cn/china/China-Japan-Relations/2014-02/25/content_17304855_2.htm). It's a [**Forgotten Ally**](https://www.goodreads.com/book/show/20256718-forgotten-ally)
Comment: I don't know how to link one question to another, but this question that was asked shortly after mine seems pretty relevant especially in light of Tom Au's answer. https://history.stackexchange.com/questions/40359/was-it-militarily-possible-to-island-hop-the-philippines-if-not-for-macarthur
Comment: Head counting how many soldiers were "tied down" is not the only factor. If Japan had created X army divisions less than IRL because they were not needed in China, this would have freed $ and resources, including supplies and logistics. How many ships or planes or whatever could they build extra? By how much their logistics situation would improve? Armies are expensive.
Answer: China was the "anvil" to the Americans' "hammer."
Japan had about one million troops tied up in China proper (and another million in Manchukuo), and one million in India and Southeast Asia not facing the Americans (except in New Guinea and the Philippines). This compares to the one and half million or so that the Americans fought in the Pacific (counting New Guinea and Philippines) and the two million that they feared facing on the Home Islands. Basically, the Chinese inflicted almost as many casualties on the Japanese as the Americans, with far inferior weaponry.
By early 1944, American B-29s were bombing Japan long range from Chinese airfields. The Japanese undertook the Ichigo offensive to capture these airfields, right at the time when the Americans were launching their central Pacific offensives. Japanese attempts to reinforce and resupply their forces in China by sea made excellent targets for American submarines.The Japanese were forced to fight a two front war against two different enemies, and lost.
Comment: I find this a bit dubious, given that the most strategic islands invaded were indeed small, and that once the naval balance swung to the American side, resupply became very difficult.  My suspicion is that most of those million soldiers would have sat on the Japanese mainland, and would have only mattered had the home island invasions been necessary.  Of course, given that the root cause of the war was Japan's actions in China, the whole question is a bit odd.
Comment: So if the Japanese had not been fighting in China they could have put more troops in New Guinea and the Philippines? Would it have mattered in places like Wake and Iwo Jima or were those islands pretty well saturated? Wouldn't the attempts to reinforce and resupply troops on islands have made even better targets for American subs? Could America have simply skipped the larger islands? Thank you for the link to the Ichigo offensive. I will have to read up on that.
Comment: @Readin: The Americans didn't have to fight the million soldiers that were killed in China/Manchuria, or the two million the remained there. They would otherwise probably have been placed on the Philippines and New Guinea, also modern Indonesia (captured by Australians late in th war). The other Pacific islands, unlike the previous, were "pre" supplied, and therefore seldom "resupplied." The Americans managed to interdict supplies/reinforcements to New Guinea, but the ones to the Philippines were escorted by the whole Japanese navy.
Comment: @congusbongus I'm not questioning the decision making that lead to the Chinese and other fighting on the Asian landmass.  Certainly at the time there was no way of knowing that America would develop an A-bomb or even of being certain that America would gain such dominance in naval and air power.  But I do wonder - in hindsight - how much the fighting on the continent mattered knowing what we know now.
Comment: @Readin I'm not a fan of this kind of thinking - island hopping was successful therefore the China theatre didn't matter - it's too Monday morning quarterbacking. The tide was turning in China too, with [Shanghai soon to be liberated](https://en.wikipedia.org/wiki/Second_Guangxi_Campaign), so the atomic bombings (using airfields including Iwo Jima) beat that to the punch, by a few months at most. Had the advances in China happened a few months sooner, we might be here arguing whether the taking of Iwo Jima was moot - note that Shanghai is closer to Hiroshima/Nagasaki.
Comment: @congusbongus About the Chinese ready to liberate Shangai, would you hace more abot that? I always thought Ichi go was the last large battle in China, and was a Japanese victory. The wikipedia article you linked is very short
Answer: There are troops and then there are troops. Even among the Germans, much less the Japanese, there was a relatively small set of highly-trained, high-quality, and mechanized divisions, and a much larger set of non-mechanized troops that were good for lesser duties like occupation.
A couple of interesting opinion, although fact-supported, articles, are at the blog linked to below.
The author makes the point that...
"The Japanese demonstrated an ability to shatter the Chinese at will – when they could spare the effort or inclination. But the great Japanese advances against the Western Allies in Asia and the Pacific were made by the ten most well trained and equipped divisions, while the Army staff acknowledged that the ninety odd divisions assigned to China and Manchuria were both fully occupied, and incapable of contributing much of additional value. Those ten divisions were of greater importance than the other 90, and no advance was possible without them..."
http://rethinkinghistory.blogspot.com/search?q=numbers+fallacy
http://rethinkinghistory.blogspot.com/2011/02/statistical-confusion-whose-troops.html
Comment: The Imperial Japanese Army did not get along with its naval counterpart.  The dominant army was  occupied guarding against a Soviet invasion leaving the heavy lifting against the U.S.to the navy.
Answer: The contributions of China in defeating Japan were major because China's territory was under attack.
I mean: Suppose the Chinese contribution was minor. Then you should accept that no Chinese contribution does not change the course of the war in a major fashion. But no Chinese contribution does not mean that China is neutral: it means that the nationalist army is defeated and Tchang Kai Chek fell.
Lets's consider a situation where China's resistance collapsed in early 1942: Then the Japanese could:

Destroy the Flying Tigers on their bases
Use one more million soldiers, including tank divisions, and some supporting air power on another theater
Have no problem on the North-East flank of Burma

Thus, the situation in the Pacific might have not changed, but in India the Allies would be in danger: Imphal and Kohima would have happen earlier and probably be victorious for the Japanese. This is a major change in the course of war because it would force the Americans to direct air, land and sea power to defend India, and thus the Japanese would have another chance to try to inflict them losses, or even beat them.
Comment: While the Burma-into-India campaign would be my first guess for where extra Japanese soldiers could have made a difference, my understanding is that it took place in a region with abyssmal logistics. Would it really have been possible to bring significantly more troops to bear on the frontlines here, even if they were available in general?
Comment: @Arno Well the Japanese lanaged to bring 3 divisions in Burma (two fighting, one in charge of logistics) and 2 in Burma in less than six months and with ennemy opposition. This could be even more important in occupied territory
Comment: How would  any success in the Burma theater influence the US navy/army at all?
Comment: @Greg Potentially because India falling is not a good idea
And less forces for British in India influences their air and naval situation, thus the Japanese are potentially in better shape against the US Navy
Comment: @totalMongot Does "the potential better shape" mean more skilled pilots? More air carriers? More commercial convoys that capable to move the row materials to the Japanese industry even under American attacks? Nope. Also, those guys were army, not navy (and in Japan the two were famously cancelling each other out during war).
Comment: Well overall this means more skilled pilots. No more air carriers, but Japanese did not lack air carriers: they lack efficiency in air and naval defense. More commercial convoys because less tied to supply forces in China


Cck date field save not working properly

Question: I am saving a date field and when i print the value as
print_r($node->mydate[0]['value']); it is printing only year 2012. This problem is only for one field. If i adds a new date type field in that content type that works perfectly.I checked all actions and in my custom code but still not found anything wrong with that. If i update timestamp value with my sql query using db_query that still have problem. I can't delete my field because of my previous content. Please help.
Answer: Check that the granularity on the field isn't set to year only. You can edit this by going to admin/structure/types/manage/[CONTENT TYPE]/fields and selecting "edit" on the appropriate field.
Comment: I am on D6 and I added the select list widget of date. I added year, date and month. With the same settings the other field is working fine.
Answer: Solved problem just by renaming the field. I couldn't found any reason what the problem was. I didn't found anything related to this in my custom code either.


Remove Netatalk "Network Trash Folder"

Question: I'm sharing files with Netatalk from Ubuntu 14.04 to Mac OS X. On my macs, there is no network trash folder, however on Ubuntu there is a "Network Trash Folder" and "Temporary Items".
Anyway to prevent these folders from getting created?
Answer: I guess you have samba installed!!!
edit the smb.conf
sudo nano /etc/samba/smb.conf

and add these lines
# Veto the Apple specific files that a NetAtalk server creates
   veto files = /Network Trash Folder/Temporary Items
   ;delete veto files = yes

uncomment the last line if you want to delete these files or folders
restart samba
sudo /etc/init.d/samba restart

and don't forget to restart your client computer

Remove Netatalk "Network Trash Folder"


Add Ponytails in avatar

Question: I don't use blender so much and I need help.
I would like to create a ponytail like the image in the link, I don't know how to create the curve (shape) in the image. Can you help me?
I appreciate also YouTube tutorial.
Thanks!
https://cgcookie.com/posts/how-to-model-hair-in-blender
Comment: Please add an image to your question so that we don't have to go to an external site to see what you're talking about. https://meta.stackexchange.com/questions/75491/how-to-upload-an-image-to-a-post
Comment: Hello and welcome. While files, images, and external videos or links may be helpful additions they should not be the only way to obtain information about your issue. Don't make understanding your question rely on downloading a file, watching a video or visiting an external site. Use the builtin tools to upload [images](https://meta.stackexchange.com/questions/75491) or [gifs](https://blender.meta.stackexchange.com/questions/963), along with thoroughly explaining the problem in written form so it can be indexed and searched for thus helping future visitors with similar issues.
Comment: Asking for links to resources about X is considered off topic here, asking directly about X is encouraged though. If you can rephrase your question to focus on the specific difficulties you are encountering, rather that point you to some site, please [edit] your post so it can be reopened. As it stands it is not a good fit for this site.
Answer: To create hair, a method is to create a curve, and under Object Data > Geometry, click on Object, and choose your Object and your Taper object, which are 2 other curves that you need to edit the way you want to define the section profile and the length profile:

Add Ponytails in avatar


How long can the National Forest put off responding to my request?

Question: I own an inholding within Inyo National Forest. I requested to gain motorized access to my property but was denied citing that it was reasonable to walk in or take mules. About a year ago, I emailed the Forest Lands Officer asking if I could do some trail repairs to make it accessible by mules. I received an email saying they would get back to me with some stipulations and guidance. That was a year ago; since then, I have emailed kindly asking for an update. I recently (a month ago)  received an email saying that someone from the NF was supposed to call me. This still has not happened. I sent another email asking for an update. In the meantime, I wanted to see if there is any legal obligation for the NF to get back to me. I've thoroughly searched the internet but have not found anything. They can't put this off forever, right?
Answer: Forever
AFAIK, they have no legal duty to respond to your request. It's their trail and the default position is you can't modify it without their permission. You don't have their permission until they grant it and they don't have to grant it. Therefore, they can ignore your communications for as long as they like.
You can approach your elected representative to apply political pressure, but you have no legal recourse.
Comment: of course you have the right to petition the government, but nothing says they have to do anything with your petition.
Comment: FWIW, in some rare circumstances you can sue to demand access.


Should I use the present form of every verb after a did?

Question: Should I use the present form of every verb after a did? Example: I didn't find anything misplace vs. I didn't find anything misplaced -> misplaced vs. misplace
Answer: The verb that goes with did in your example isn't misplace(d). It is find, which is correctly in "the present" form (actually bare infinitive, which isn't the same, but let's not split hairs). Misplaced is acting as an adjective here, not a verb.
Comment: It's not "correctly in the present form" - it's ***only*** an unmarked infinitive.
Comment: @FumbleFingers Sorry, I'll add the dubiousness quotes... done. Happy?
Comment: I'll go for that. I realise you probably think I ***am*** splitting hairs, but I think it's bad enough that many nns learners (although virtually ***no*** native speakers) refer to "Past Infinitive" in the context of English verb forms. We should stick to standard terminology.
Comment: Oh, I've nothing against hairs being split for good reason.
Answer:
I didn't find anything misplaced

In this sentence "misplaced" isn't a verb but an adjective. Take this sentence for example

I didn't find anything wrong.

And yes did shall be followed by a bare infinitive.
Comment: Eefar, it's not the present form, it's the bare infinitive. @Faminha: what sort of sentence are you talking about? If they are two verbs that are actually what *did* is applying to, then they are both bare infinitives, like "I did run and jump" (don't use that, it's a contrived example).
Comment: Nice! Thank you. What about when there are two verbs after a Did? Are the twos in the bare infinitive, or only the first?
Comment: I was not aware of that. Are all the verbs that follow "did" bare infinitives?
Comment: @eefar Yes. Generally any verb that follows an auxiliary like "did", "do", "have", "was" and so on will be in a non-finite form. That can be a bare infinitive, a past participle or a progressive participle (or, depending on interpretation, a gerund, which looks just like a progressive participle).
Answer: Only one verb (usually the first) in each clause takes a finite form. In "I didn't find anything misplaced", "did" is the finite verb, and it's in the past tense. "find" is the bare infinitive, which as the name suggests, is not a finite form. "misplaced" is the past participle of "misplace", and participles are also not finite forms. With a lot of verbs, "misplace" included, the past participle and past tense look the same, but there are some verbs such as "break", the forms are different, and with those verbs it's clearer what's going on. It's not grammatical to say "I didn't find anything broke", because "broke" is the past tense (finite) form of "break", but it is grammatical to say "I didn't find anything broken", because "broken" is the past participle (nonfinite) form of "break". So when the past tense and past participle for a verb are different, make sure to not use the past tense if it's not the main verb in its clause.
Comment: We don't usually call the auxiliary verb the main verb. The main, or principal verb is the one that defines the main action (or state) of the sentence or clause. Where there's an auxiliary, it is the one that inflects for person and time, you're right about that, but that doesn't make it the main verb.


How does the Mi-26 tilt its rotor like this?

Question:
I watched this video on YouTube, which shows an Mi-26 taking off with its rotor tilted forward about 45 degrees. Is the video fake or is it real, and if it is real, how does the Mi-26 do such a thing?
Answer: It's real and it's simply the blades running at the flapping hinge limits with the cyclic stick full forward.  The blade on the back is at its up limit and the one at the front at its down limit, resulting in an overall disc angle of about 30 degrees off horizontal.  It's being done to accelerate along the ground as fast as possible.  In the air, the machine's body will follow the tilt of the rotor quickly enough that this sort of angle is almost never experienced unless the pilot made a sudden extreme input in flight.
This (blades hitting flapping limits) is something that only multi-blade articulating rotors can tolerate.  You can't do that with a two blade teetering rotor because contacting the blade flapping travel stops, known as mast bumping, will break the mast.
Comment: @ZeissIkon not necessarily, the RuAF uses running takeoffs routinely because they are [safer](https://aviation.stackexchange.com/a/39700/23223).
Comment: Worth noting that this is being done in order to obtain translational lift as quickly as possible -- suggesting that this is either a heavy or high-performance takeoff.
Comment: Im gonna pretend I know everything you said.... anyways, you mean the rotors are attached to hinges like on every door?
Comment: @ipydawa there are [many different rotor hub design solutions](https://www.faasafety.gov/gslac/ALC/course_content.aspx?cID=105&sID=462&preview=true), the Mi-26 uses a fully articulated one: [image](http://www.aviastar.org/foto/gallery/mil/mi-26_4.jpg)
Comment: The blades on 3+ blade rotors are traditionally attached to hinges that let them move up and down and when viewed as a whole, looks like a disc tilting this way or that.. On more modern rotors, they do away with the hinges and provide a flexible attachment using either soft bushings (called "elastomeric" bearings or bushings), or just make the blade root flexible like a fishing rod, that allows the blade to do the same thing, but the result is the same. On a two blade system, the blade going up naturally does so in coordination with its opposite partner, allowing a single hinge in the middle.
Answer: It's less than 45 degrees, I think. Probably less than 30.
There's nothing special about that. That helicopter is built with an important amount of forward cyclic. It's not the rotor head itself that tilts, but the tip-path plane is tilted with the cyclic command...


Why do all flashbacks show the person who's remembering it as if they're being filmed?

Question: What I mean is this: a person will have a flashback, and unless the majority of the flashback takes place in front of a mirror, the person remembering should not be able to see themselves in the shot. For these to occur, why don't they film the scene twice, once from a 3rd person perspective, and once from a 1st person perspective?
Comment: I think this is a fair question - & answerable from 2 perspectives. [The 3rd consideration would be budget - did they shoot the flashback at the time of the current 'episode', or are they having to re-use older footage that they never planned to be used as a flashback?]
Comment: I think one can surely find a film where flashback is filmed in 1st person perspective. I do not think there is clear answer to this and this Q is primary opinion based. For example there are many reasons: filmed or added later and easier-cheaper to use old shoots than to-do new ones in 1st person, for the audience sake who is used to watch films as 3rd person (same applies to dialogue and other similar situations).
Answer: I can't say why things are filmed the way they are.  But I can say that a lot of people remember things in a 3rd person perspective, and in fact a lot of people remember some things in a 1st person perspective and other things in a third person perspective.  There is a lot of psychological research about this and the factors that influence how people visualize memories.  For starters here is the wikipedia entry about it:
https://en.wikipedia.org/wiki/Autobiographical_memory#Memory_perspectives
I tend to remember things in a third person perspective most of the time, so to me, a flashback should be from the third person perspective, with the recaller seeing themselves in the memory from a distance.
Comment: I'll wait a day. If no one else answers, you've got the points
Answer: chuft probably has the psychology of it nailed, but just another point, from a cinematic perspective...
If the entire scene were shot from the protagonist's PoV, it would start to look very uncomfortable.
Firstly, there could be no cuts, as the scene would have to be done in a single shot to maintain the first person perspective. Cuts would feel jumpy, as there would be no clear indication as to why there was a cut.
The camera, unless placed so the protagonist was essentially still and facing a single direction for the duration, would have to pan considerably, as the PoV swung to new points of interest. Our eyes do this all the time, but a camera just can't reproduce the effect.
It would be the equivalent of following a runner with a hand-held camera [no steadicam] - it works for a short while, but you'd get dizzy and lose the plot after a minute or two.[2]
It would probably be OK if [s]he were looking at events from a distance; shot through a bush etc as though they were peeking at the events, though it wouldn't clearly signify who it was doing the peeking without at least one shot of them doing it, to clarify the position to the audience.
It would look very much stranger if it was a dialogue scene - a conversation between protagonist and others... all the others would be constantly looking right down the barrel of the lens[1]  - something which really breaks the immersion of a scene for the audience.
Breaking the fourth wall, as it is called, is usually [sparingly] employed to indicate that the protagonist is speaking directly to the audience, outside of the context of the scene. House of Cards is one of the most famous recent examples of this, though it's by no means a new trick.

[1]
I've seen this technique used, though I can't remember the movie. Maybe a Hitchcock or similar. It was done on a wide lens in combination with a [moving?] blur to indicate the person was 'stuck' or 'trapped' and just staring at the ceiling, maybe in a hospital bed with people coming in and out of shot to interact with the patient. iirc, the amount of eye-contact was kept to a minimum... a nurse would say hello, then get on with changing the drip etc.
There is a technique to looking at rather than down the lens, usually done by putting a mark on the edge of the matte-box [the black square surround on the lens] so that the eye-line is just off to one side.
[2] Late edit
I just recalled, Game of Thrones does this for the wargs' PoV as a wolf etc. Note they don't keep it up for long, as it's quite confusing.
Comment: There are also many shows that use first person shots to showcase any monster/wild animal/stalker roaming around in the wild (before the protagonist is aware of them), mainly to hide the identity of the monster while still providing evidence that it must invariably exist. Predator and Doctor Who comes to mind, and many other examples.
Comment: Funny, this applies to 90% of scenes and is not limited to 1rd or 3rd perspective approach.


Why pulley systems give mechanical advantage?

Question: In a system with 2 pulleys, to lift a x kg object y meters I would need half the force that the object exerts due to gravity but pull the rope double the distance, why does this happen this way?
Comment: Think of it like a lever, one part moves more than the other...
Answer: This can be viewed as a requirement of the work-energy theorem and the conservation of energy. Assuming you alter the system slowly enough that parts don't gain a significant kinetic energy, the work you do by pulling the rope must be equal to the work done against gravity or any other forces that may be applicable. If you pull the rope with a force $F$ by a distance $a$, and the object of interest with weight $W$ is lifted a distance of $b$, we have
$$ F a \ge W b, $$
where equality holds in idealized systems where work is only being done by pushing the weight $W$ against gravity. For a pulley system, this means having no friction, massless strings and massless pulleys. If $ a = 2b $ in such an idealized system, then $ F = W/2 $.


Kernel of Hankel Transform

Question: I need to solve a cylindrical diffusion problem that is defined in $[1,\infty]$. I would like to use Hankel Transform that has is defined on $[0,\infty]$. So in order to apply Hankel transform in my case, do I need to change the Kernel of the Transformation.
Comment: You probably have a condition at $r=1$. So your transform should be tailored to that condition.
Answer: Yes, you do.
In general, the Bessel solutions to the boundary value problem require that the function remains finite at r = 0.
If your domain does not include r = 0 (and yours does not!) then you need to use a linear combination of Bessel functions of the first, and second kind.
A bit of Googling will help you to get a good idea about how to go about this. For example, "Theory and Operational Rules for the Discrete Hankel Transform" is a very nice paper which attempts to put the DHT on equal footing with the discrete Fourier transform.

Kernel of Hankel Transform


Are questions about core magento features off-topic?

Question: I want to know more about the differences between Community and Enterprise, specifically what features are included in the core functionality that we wouldn't need extensions to do.  Is this type of question off-topic?
To be clear, I am not looking for an itemized list of features, but specifics.  For instance, with our current Community installation, we have an extension called "Multi Warehouse" that provides functionality to adjust multiple inventories, split orders based on which warehouse the items will ship from, calculate different shipping for each split order, etc.  But this extension is causing some difficulties with other extensions, and even with some of the core functionality (very subtle stuff, but tested and confirmed).
So my proposed question would be something like: "What functionality does Enterprise offer to deal with multiple inventories and shipping centers?"
I am not looking for the answer here, just whether this would be on-topic for the Magento Stack Exchange.
Answer: No, these types of questions are absolutely valid.
And no, EE is not providing functionality for managing multiple stocks.


Offsetting capital gains with previous losses

Question: I only trade options. Nothing exotic but just buying and selling CALLS and PUTS.
So for example if I lost 30,000 USD trading options for the 2020 Tax Year. In 2021 I go on to profit 40,000 USD. Does this mean I can offset 30,000 from previous years losses and only owe taxes for 10,000 ?
Answer: For 2020, if you had no gains to offset, you would take $3000 against ordinary income.
Then $27,000 is carried forward and would offset up to $27,000 of gains.
Answer: The annual deduction for losses is $3k so your carryover loss from 2020 would be $27k which would offset $27k of gains in 2021.
However, if you qualify for Trader Tax Status, the $3k annual limit does not apply.  Read this if interested in more details.
Comment: "Holsinger was in 2008 and the court held that the actual days where trades occurred (i.e. the taxpayer executed 372 trades on 110 days) was a rationale for excluding the taxpayer from trader status as the trading failed the "frequency, continuity and regularity" test."  That is quite a high bar. From the nature of the OP's questions, I'm guessing this won't apply. But, good to know, regardless.
Comment: That is an insanely high bar.  When I lived off nothing but trading I would make a few dozen trades a year tops.
Comment: 372 trade in 110 days fails the frequency and quantity tests.  LOL, I've done that in a week (back in 2008). The Poppe vs. Commission case  awarded trader tax status (TTS) with 720 trades (60 trades per month).  For other limits, see the Green Trader Tax opinion on it.
Comment: @Fattie must have been nice only working a few minutes per month that year. ;)


Is it possible to have separate permissions for a form and the library it submits to?

Question: We are using SharePoint 2010 and InfoPath 2010. I would like a form hosted on SharePoint to be available to any logged-in user, however after they submit I would like the library that receives the form to only be viewable by a custom group. Is this possible using only permissions in SharePoint? Or does the form take its permissions from the library hosting it? If I embed in a page viewer does it inherit permissions from the page its embedded in?
Answer: I was wrestling with this a while ago and while I never implemented it, I came up with a couple things to try. These may not be correct (someone else can probably offer more insight) but these are what I'd try.
Create a library that has write permission for all, but not read, then create a form with a specified submit path to that library. I think that should do it. If not, my alternate plan was to create a workflow to grab any form submitted to a "drop box" library and route it as needed. That would be more complex and require more effort, but I think that may be a good plan b. I look forward to hearing if this works as I will very likely be doing something similar in the future!
Answer: Set the default view of the forms library to a filter that does not return any documents.  Users can create new items, but will not see any items in the library. Don't allow users to create personal views on the forms library.
Create a document library with web part or wiki pages. Add list view web parts showing all forms in the forms library to such a page. Allow access to that page only for the custom group.


Which is perferred - a standalone login page or a javascript popup over a MyAccount page?

Question: I am designing a new website, and am thinking about the UX for accessing a personal account page. Is it "better" to have a standalone login page (and then redirects to My Account details), or a Javascript popup which is on top of the My Account page?  In the first situation, the interface will be "cleaner" (less potential clutter appearing to the user), but in the second scenario, it might appear like a faster, more streamlined UX.  Are these correct observations? Any other reasons pro/con to consider one over the other?
Comment: So users can already be on the *My Account* page before they need to login?
Comment: @Izhaki only if navigating there initially. If they are not logged in, then the JS popup should appear, or they should be auto-redirected to a login page.
Answer: Often times you need both.
The pop up sign in (or a drop in panel) is the smoothest experience for most use cases. It allows users to sign in without leaving their current path.
But you will also run into cases where you need to land users on a sign in page. In my experience, this should be the exception, not the standard.
One example of the exception path:
The user follows an inbound link to a registered user function (via an email, bookmark, help link, etc). If they don't already have a session cookie set, you'll want to land them on an intercept sign in page. Be sure to open with a brief but helpful message explaining the interruption.
Comment: @Conrad At this point, if you don't like js the web doesn't want you!
Comment: Can you talk about scenario(s) where you have seen the exceptions happen? I am not coming up with any off the top of my head.
Comment: @Conrad I added the most common scenario I've run into.
Comment: +1 Also, another reason is if the browser disables javascript, a page redirect is often necessary as a fall-back.
Comment: Yeah, there's a handful of good, undesirable reasons to have that alternate path ready  (^‿-)
Comment: @tohster if JS is disabled; my site simply just won't function - it's a prereq. (I will create some little note for the 1% who feel the need to do that. :) )
Answer: I agree that both are beneficial, but a separate login page is essential.
The reasons for having a login page on it's own page shouldn't just be to "declutter" but rather it should be decoupled in the case where a "users" primary task(s) have to do with logging in. I think the pop-up works but should be carefully considered, if the login is "in the way" of what the "user" is attempting to accomplish, I can see why the popup is better.
Pairing social understanding
In some of my past social research (primarily United Kingdom/United States) some groups have learned through experience and second hand experience (socially and culturally) that popups are not to be trusted.
Some first hand "users" experienced popups as "unstable", unforgiving, demeaning, and "fragile".

Unstable: they leave (especially on mobile) if you accidentally press around it unlike the regular space.
Unforgiving: "If I get something wrong, It doesn't come back or wanna help me"

as a social scientist this was fascinating for me.

Fragile: Since it isn't a real screen I may not have the url to go back to and it may not save anything.

I also recall that auth helper apps including web browsers, ones that keep password data rely on "urls" to autofill data. I recall one of these usability tests where a user attempted to login to MediaTemple (mediatemple.net), which features a "responsive" break point which somehow points , but they had to navigate to the login page . The browser's login did not autofill the initial popup form,
If the width is 985px or smaller then you are given a hamburger menu.

After clicking login you are provided with a popup. Notice the autofill does not work on the popup.

If the width is 986px or greater then you can click the text "Login".

The "Login" text takes you to a private login page where autofill works successfully.

When the user reflected on this, they noted how they used an in-browser password generator, which means that certain users may not ever become familiar with their password. In this case the "user" increased the browser width and clicked login to avoid having to reset their password.
Some sensorial research reveals that digital user interface objects like "pop-ups" have perceived "weight" just as material does. Some of these same  "users" translate "pop-ups" as being "cheap", "not-so-safe (for my data)", "light"(could be positive).
The idea here is that while materials can be directly touched, digital user interface objects inherit our understanding of "material". When we figure out that the material glass is fragile, the result is our embodied and thoughtful action around glass becomes careful and strategic. Whether we  watch a glass vase shatter into a million pieces, mum and dad insisting we never touch or sit on the glass table, and/or learning the "atomic" structure, serve to teach us how to deal with such a material. The issue with this learned "definiteness" is that it will probably be tougher for people to be immediately ok with standing or jumping on glass or begin believing that it can also stop a bullet.
Whether it's glass or "pop-ups", objects have a history that social groups see and experience differently. Pop-ups may be remembered as being obtrusive web adverts or virus carriers (you won a prize) to being the cause behind the flush of pop-up blocker plugins, this understanding will provide/influence certain "users" with how they understand and engage with your designed solution.
So the goal may be to understand what's already there for "users" and their understanding of "pop-ups" beyond formal rules of cognition or bias.
If you should choose to use pop-ups I believe that the decision should consider looking at how your "users" experience certain components beyond analysing the differences in speed, but also to look at how different groups "understand" components and it's historical context and incorporate this understanding into your design. That may mean building a pop-up form that gives a sense of security and responsiveness or not using them at all.
Comment: The autofill of usernames/passwords is an important reminder. I use LastPass, and unsurprisingly really dislike it when it won't work on a site.
Answer: How user could go into a page with out log in to ?
I have never seen any major website use pop up for log in ; i think one of main reasons ; it's not accessible.  but if  are looking to find a solution that user don't leave  the page , you could go for drop panel .
Answer: What about XSS - cross-site scripting?
Due to security reasons, it is advisable to implement stand-alone plain html login pages (as well as other sensitive pages) with as few external dependencies as possible.
In the current meta of rich javascript applications, that means to actually exclude the login page out from the application and:

no linked external libraries hosted on public CDNs
no javascript module dependencies from NPM or others
no everything that isn't hosted from your own server/files

link: A comprehensive tutorial on cross-site scripting
hackernoon: I'm harvesting credit card numbers and passwords from your site. Here's how.


Auto reconnect two identical USB devices in VSphere

Question: I have two identical APC UPS's that have USB controllers. I want to map both of the USB ports from the ESXI host to a VM and always have those USB devices reconnect, including if they are unplugged or the VM is restarted. Both of those devices have the same Vendor and ProductID though. When I restart the VM or unplug and replug the cords only one USB device gets reconnected. Are there any solutions for this?
Answer: At this time there is no auto-reconnect feature for the USB devices.
My suggestion if you're concerned about shutting down VMs within VMware is that you would look into the powerchute software that either connects over the network to each computer individually or use the integration of the UPS with the VMware servers themselves and set up alarms/actions to gracefully shut down the servers.
Answer: I was able to get this to persist through a reboot & usb disconnect/reconnect. I had to edit the VMs .vmx & change usb.autoConnect.device0 to autoclean:0. Referenced this VMware KB. As long as I insert the USB plugs back into the same USB slot it works.


How to calculate Virtual Memory Size in Mavericks

Question:
I would like to know if there is a command (or set of commands) that calculates each of (Virtual Memory, File Cache and App Memory) parameters listed in the screen shot above.
Answer: I believe between top and vm_stat you could get most of that output, though in a less legible form. (Why do you want to read it from the terminal, curiosity?)
top has most of the physical and virtual memory stats, but vm_stats has the amount of compressed, and they both have swapping, though thanks to compression that is low.
App Memory and Filecache specifics I could not find, they are included in virtual memory count.
vm_stats:
Mach Virtual Memory Statistics: (page size of 4096 bytes)
Pages free:                              262614.
Pages active:                            818894.
Pages inactive:                          287658.
Pages speculative:                        46300.
Pages throttled:                              0.
Pages wired down:                        411565.
Pages purgeable:                          56793.
"Translation faults":                 255617431.
Pages copy-on-write:                   10812762.
Pages zero filled:                    165910381.
Pages reactivated:                      3419113.
Pages purged:                           2058688.
File-backed pages:                       246635.
Anonymous pages:                         906217.
Pages stored in compressor:              396258.
Pages occupied by compressor:            269783.
Decompressions:                          625574.
Compressions:                           1816628.
Pageins:                                1693962.
Pageouts:                                223513.
Swapins:                                      0.
Swapouts:                                     0.

top:
Processes: 253 total, 2 running, 6 stuck, 245 sleeping, 1101 threads             14:53:50
Load Avg: 1.42, 1.43, 1.62  CPU usage: 8.52% user, 5.97% sys, 85.50% idle
SharedLibs: 120M resident, 0B data, 26M linkedit.
MemRegions: 70307 total, 2561M resident, 107M private, 577M shared.
PhysMem: 5919M used (1608M wired), 1218M unused.
VM: 631G vsize, 1312M framework vsize, 0(0) swapins, 0(0) swapouts.
Networks: packets: 7933197/5221M in, 5685549/2563M out.
Disks: 1748536/37G read, 1726987/42G written.

Edit: Ok I looked around for a tool that might find that value of virtual memory. I believe the virtual memory value shown in 'Activity Monitor' is how much memory is really being used. Whereas 'top' shows all virtual memory, and most of it has not been actually placed somewhere. Programs may request a lot more memory then they will use, and since it is virtual memory it doesn't cost anything to let them have a large vm space as long as they don't actually use it.
This link has a top replacement tool  If you run it with 'sudo' like 'sudo procexp -all' it gives out what virtual memory may be more along the lines of what 'Activity Monitor' shows.
-----------------
Process: 0  Name: kernel_task       Parent:     0   Status: runnable
Flags:   64-bit,system,session leader
UID:        0   RUID:     0 SVUID:     0
GID:        0   RGID:     0 SVGID:     0

Virtual size:       7167M (7515574272)  Resident size:         752M (789536768)
Time:     58.03   =   00.00 (User)    +    58.03 (System)
Syscalls:           0   Mach Traps:       0
Disk I/O: Read   9786K  Written:      88547K

#Threads:  96     (Process has no workqueues)

Comment: Thank you for your prompt response but I still can get 12.6 GB number of Virtual Memory shown in screen shot above. The top command returns strange numbers for ex in your answer its say 631G vsize. I just need to get the 12.6 GB number and I want to get it in any way that can be called programmatically (terminal commmand/API/...).
Answer: You can use vm_stat and sysctl terminal commands. Although there was no straightforward way or documentation on how to extract the new attributes from these commands, we had to do some trial and error till we discovered the relations between parameters in the commands and the attribute we need to calculate.
The Steps are as the following:

Run vm_stat
Run "sysctl hw.memsize" and "sysctl vm.swapusage".
The relationship between Memory usage which appears in Activity Monitor and previous commands are described in How to calc Memory usage in Mavericks programmatically.

Sample output from vm_stat:
Mach Virtual Memory Statistics: (page size of 4096 bytes)
Pages free:                               24428.
Pages active:                           1039653.
Pages inactive:                          626002.
Pages speculative:                       184530.
Pages throttled:                              0.
Pages wired down:                        156244.
Pages purgeable:                           9429.
"Translation faults":                  14335334.
Pages copy-on-write:                     557301.
Pages zero filled:                      5682527.
Pages reactivated:                           74.
Pages purged:                             52633.
File-backed pages:                       660167.
Anonymous pages:                        1190018.
Pages stored in compressor:                 644.
Pages occupied by compressor:               603.
Decompressions:                              18.
Compressions:                               859.
Pageins:                                 253589.
Pageouts:                                     0.
Swapins:                                      0.
Swapouts:                                     0.


Sample size and documentation for discriminant analysis

Question: Does anybody have good documentation for discriminant analysis? I have 9 variables (measurements), 60 patients and my outcome is good surgery, bad surgery. Also, is my sample size too small?
Thank you
Answer: I have 3 points to say. First, what is "good" documentation for you? There is a lot of pages on DA and downloadable books on multivariate statistics (where DA is discussed) in the Internet. Some texts are superficial and easy, some are more sophisticated.
Second, because you have just 2 groups your DA will be virtually equivalent to the multiple linear regression with "Groups" dependent variable and your 9 variables as independent variables. The results (coefficients) after DA and the regression will be proportional between the two analyses. So, if you know linear regression that will suffice to understand the results even if you don't know DA.
Third, whenever there is just two groups it is worth considering to prefer binary logistic regression to DA. The logistic regression is less hard-to-plese in regard to assumptions than DA is. Just to mention some: it doesn't require multivariate normal distribution; it doesn't require equality of variances-covariances between the groups; it is less sensitive to disproportion of groups sizes as well as to outliers.
Comment: Thank you. I am advising a student and he is interested in doing DA instead of logistic regression. I explained to him that I prefer logistic regression in his case and I will reiterate that to him. As for good documentation, I am looking for something that explains the discriminant functions and their coefficients as well as the canonical correlations and their meanings. I hope you can help.
Comment: Can you also tell me when is DA preferred to logistic regression?
Comment: @Sara, I'd explain fundamentals of DA right in my answer if I had time. Sorry. _When_ assumptions of DA are met (i.e. normal distribution etc.) DA usually classifies objects somewhat more accurately than LR.


Having someone else file a patent application to retain micro entity status

Question: Budgetary concerns require me to file my patent applications under micro entity status.  I meet all requirements.  However, one cannot submit more than five (maximum four previous) applications at the micro entity filing rate.  I have more than five separate inventions, which makes this a problem.  The obvious thing to do is to file them under a different name, but there is a technicality which states that one cannot file patents in another person's name with any agreement of payment between the parties.  However, I wonder what exactly constitutes payment.  What if, for example, I file some patents in my wife's name (or my mother's name, or my sister's, etc.), and any income generated by the patents is directed into an account of which we are joint owners?  Is this legal?
Answer: You probably shouldn't do this. Even if you filed it in another person's name, you would still be the inventor (who must also satisfy the application filing limit).
37 CFR 1.29(a) requires (emphasis added):

(a) To establish micro entity status under this paragraph, the applicant must certify that: ...
(2) Neither the applicant nor the inventor nor a joint inventor has been named as the inventor or a joint inventor on more than four previously filed patent applications, other than applications filed in another country, provisional applications under 35 U.S.C. 111(b), or international applications for which the basic national fee under 35 U.S.C. 41(a) was not paid;

MPEP § 509.04(a) provides a bit of extra discussion:

All such applications naming the inventor or a joint inventor are counted toward the application filing limit, whether the applications were filed before, on, or after March 19, 2013. Further, it does not matter whether the previously filed applications are pending, patented, or abandoned; they are still included when counting to determine whether the application filing limit has been reached.

It therefore seems quite clear that you would not satisfy the requirements for claiming micro entity status.
The consequences of claiming the wrong entity status can be dire. There are a number of examples in the past relating to wrongly claimed small entity status, where the patents were consequently unenforceable. I would assume the outcome would be no different for wrongly claiming micro entity status.
Comment: That is unfortunate.  Thank you for the information.
Comment: "where the patents were consequently enforceable" - I assume this was meant to mean unenforceable?
Comment: @DonQuiKong Yes indeed. Quite an unfortunate mistake.
Answer: I am a layman but it sounds like you are trying to skirt the law and it doesn't sound legal.
I suggest when you are ready to file the others do so as a small entity where fees are reduced by half ... hopefully by the time you are ready you would have earned some income from the previous patents:
http://www.uspto.gov/learning-and-resources/fees-and-payment/uspto-fee-schedule
http://www.uspto.gov/sites/default/files/aia_implementation/AC54_Small_Entity_Compliance_Guide_Final.pdf


Let P be the language of palindromes over the alphabet Σ = {0, 1}. and let P' be the subset of the palindromes with different numbers of 0s and 1s

Question: Let P be the language of palindromes over the alphabet Σ = {0, 1}. and let P' be the subset of the palindromes with different numbers of 0s and 1s. Is P' context-free? I know that for the language of the set of palindromes with the same numbers of 0s and 1s is not context-free.
Answer: Intuitively you cannot check palindromicity and (un)equality of numbers using a single pushdown, so also $P'$ must be non-context-free.
Formally proving unequal-repeating-numbers to be non-context-free is quite a challenge, see How to prove L := { a^n b^n c^m | n,m >= 0 & n != m } is not context-free? for the language $\{ a^nb^nc^m \mid n\neq m \}$. For that language one needs a special $p!$ trick, as well as Ogden,  a stronger form of the classical pumping lemma.
If one intersects your language $P'$ of strings that are palindromes and have unequal numbers of $0,1$ with $0^*(11)^*0^*$ one obtains the language $\{ 0^m 1^{2n} 0^m \mid m\neq n \}$. It seems reasonable to attack that language with similar methods. Then it would follow that $P'$ itself is not context-free as context-free languages are closed under intersection with regular languages.
Comment: Thank you! I think this is a good way of proofing. Is there any way to do the proof without Ogden, perhaps just using the pumping lemma and intersecting/union of two languages?
Comment: It would be nice to have such a more elementary proof. We have $P = P'\cup P''$, where $P',P''$ have unequal, equal number of $0,1$. Then $P$ is context-free and you claim that $P''$ is not context-free. I cannot conclude that $P'$ is non-context-free, but perhaps I am overlooking some simple argument.

Let P be the language of palindromes over the alphabet Σ = {0, 1}. and let P‘ be the subset of the palindromes with different numbers of 0s and 1s


SPD 2013 text workflow Termination

Question: I have a Termination workflow that runs If Nature is changed to termination
I would like a separate workflow to be run after the Termination workflow and check IF "Last day of Contract" Date field is (that Date i.e. 27/02/2018 + 90 days) and IF Yes then send an email. But I would like the workflow to check each Terminated employee "Last day of Contract".
Answer: in list settings/information management policy settings
you can create a retention policy to run a sp2010 workflow
you can define your conditions based on a date, then the retention policy timer job (daily timer job) will fire the workflow when the date condition is met
Comment: Thank you for answering me! I followed your steps, but I cannot see where to Add a new policy , Under "List Based Retention Schedule" I see " Source of retention for this list:  Content Types (Change source)"  then under "Content Type Policies" I see Contact, Folder and Workflow Task(SharePoint2013) all three have "Policy" as none and "Retention Policy Defined" as No.
Comment: Also the list has 4 different "Natures" meaning States, i.e. New hire, Consultant, Change, Termination. I only want to affect the Terminations and not any other items with Nature being other then Termination. I basically want to send a reminder email back to Managers after 3 months have elapsed from date of Termination reminding them to copy any emails and OneDrive data before its deleted for ever.
Comment: you have to click on the content type you want to run the policy, probably your content type name is "contact",
once there you'll have to tick the enable retention checkbox and there you are going to select the use 2010 workflow,
on the workflow you need to place the If condition to only affect the state that you want
Comment: Thank you so much! I realized that I had to create a 2010 workflow and called it "Termination Reminder" this 2010 workflow only has one thing "Send Email" . I am about to put this into place, but before I click OK then OK again to save it all, Can you answer 1 question. Will this Event trigger on all my current existing Termination items that have an entry in "Last Day of Contract" plus 90 days? I must have 500 entries, or will this only start triggering for New Termination events? I dont want to break anything :)
Comment: it will trigger on all the items that have last day of contract populated, so you have to add the condition inside your workflow to avoid it to send emails on other items

SPD 2013 text workflow Termination


What does non-integer bond order mean?

Question: I am studying molecular bond theory, and I see that sometimes this happens.
Does this have some significance to the molecule?
Answer: It is one of the man-made tools to conceptualize the nature of a bond between two atoms, to know if there is a single / double / triple / quadruple *) bond between them, and to account for both electrons involved in bonding / antibonding molecular orbitals.  Because the nature of electrons is neither "true and only" particle, nor wave alone, hence sometimes escaping our day-to-day experience with macroscopic objects.
In addition, rarely you look at the bond order of two atoms in a molecule without keeping in mind the situation with other atoms present in the same molecule, too.
*)  Sorry, I forgot at least the three-centre-two electron bonds in diborane...
Answer:
Bond order is non-integral when the difference in the number of electrons in molecular orbital and the number of electrons in anti-molecular orbital is odd.
I don't see anything "significant" in the difference being odd.
Answer: Bonding is more complex than a simple 2-electron picture suggests
In the teaching of chemistry and in the early development of the theory of chemical bonding, bonds are (or were) often thought of as consisting of two shared electrons. This is where the idea of bond order comes from: a bond consisting of two electrons is a single bond (as in a hydrogen molecule). Some elements have enough electrons arranged in the right way to give higher bond orders because more electrons are shared (in nitrogen molecules six electrons are shared between the two nitrogens giving a bond order of 3).
This picture, given how simple it is, does a surprisingly good job of explaining the structure of many chemicals and a great deal of organic chemistry. But it is an overly simplistic picture. Sure, ethene is easy to explain: there is bond between the carbons that has a bond order of two. That bond is shorter than the C-C single bond in ethane but longer than the C-C triple bond in ethyne (acetylene for traditionalists). But this simple picture falls apart for other molecules. In benzene, the archetypal example, we could write the structure as cyclohexatriene with alternating double and single bonds around the six membered ring. That certainly uses up all the electron pairs. But this neither explains the reactivity nor the measured structure where all the bonds are the same.
In reality six electrons in benzene are shared equally among all the bonds ("delocalised" is one way to describe this). Each bond is shorter than a single bond but not as short as a double bond. There is no point in trying to explain this using the simple picture where all bonds share two electrons and have an integral bond order. So we say those bonds have a bond order of 1.5 which is compatible with the actual physical structure.
A full explanation of how those bonds works requires some molecular orbital theory and more complex structures where bond orders can be other fractions are not uncommon. But without getting in the details of more sophisticated theories of bonding, the basic explanation of non-integer bond orders is that electrons are sometimes not very monogamous and share themselves between several atoms in which case we get bond orders that are not integers depending on the number shared and the numbers of atoms involved in the sharing.
Answer: Bond order not being a whole number usually happens when the molecule has different resonant structures....basically what one should understand first and foremost is that a chemical bond is not the stick like thingy we draw...the stick/line is just a representation of the bond...hence a non whole number bond order means a non whole number bond order...which you obtain from 1/2(Nb-Na)..where Nb and Na mean the no of electrons in the bonding and antibonding orbitals respectively
Im not really too sure it means anything more than that

What does non-integer bond order mean?


Did Light Actually Like L (in a friendship way)?

Question: When I watched episode 25 of Death Note (AKA the one when L, Watari, and Rem died), I noticed that Light was strangely kind to L. Is that because he was nice to L before he died, or because he actually thought of L as a friend? This is something I have been pondering over ever since L said that Light was his only friend.
Comment: Related from the opposite PoV: [Was Light actually a friend to L?](https://anime.stackexchange.com/q/62095/2516)
Answer: This might be my personal opinion, but this does not look like the face that a person would show his friend when that friend is dying. Light had been pretending to be L's friend for a while, so by (over-)reacting he achieved two things. The first would be keeping his image and the second would be giving him a reason to go looking for the Death Note, that he knew would be laying around somewhere.
Answer: In the Chapter 32 (Vol. 4), Light was thinking if he should kill L or not, and then Ryuk said he thought that Light's doubt was because L called him his friend. Then Light answered that on the outside, Ryuuga/L is his friend, but actually L is Kira's enemy. And in various other pages, you see Light thinking about "killing L" - hardly a thing a friend would do. So, no, Light (at least with the memories of being Kira) doesn't consider L truly a friend, it's just part of his acting.
Answer: No, he only saw him as an obstacle, but I assume he respected him. Otherwise he would not have gone to such great lengths to kill him.
Comment: I'm not sure I see your reasoning. Light had to kill L because he was an obstacle to Light's plan, the greatest obstacle. Respect had nothing to do with it, unless you just meant "respect to the danger L posed to him". But I read your answer as "respect for L's intellect and skill". Please clarify.
Comment: Yes, as in he saw that he was a threat due to his potential for catching him and thus respected his skills.
Answer: I do believe so yes. Light (that being the Light who didn't realize he was Kira), did like L and considered him a friend. But Kira (that being, the Light who has Kira's memories) considered L his enemy.
What is interesting and what I feel is not really considered by fans, is that Light and Kira are the same person.
Light without his memories, is STILL Kira.
Kira WITH his memories, is STILL Light.
What I mean is, just like how Misa would still remember her feelings for Light even while losing her memory, likewise, I do believe Light would still remember considering L a friend during their investigation together (after he'd lost his memories).
His Kira self is more dominant, but based on how Light was seeing L when he looks at the empty chair, and laments on how things aren't interesting without L, and even cut scenes to Light's blank looking face when he's on a date with Misa right after his lamenting about L being gone, it gives off the idea that Light, somewhere deep down, misses L.
He misses the challenge, he misses his "friend." Even though L was Kira's enemy, Ryuuzaki was Light's friend. They had much in common, they were equals, literally no one could match up to them the way they did to each other, so no matter what, Light found something unique in his relationship with L. I do not believe he never cared at all.
It's just that he cared about being God of the New World far more, and thus was willing to throw away everything else for it.
Answer: There are many animes I have come across that have characters with split personalities. I think this is the case with Light. I believe Light is not truly evil, but his other persona (Kira) is. I think this is also the case for Light and L's relationship. Light does consider L as a friend whereas Kira sees L as his enemy. Although many fans think Light acted a lot, I think there were plenty of moments where Light and Kira were in conflict inside Light. As I read elsewhere, If Light had never found the death-note and became Kira, he would have become a detective alongside L and the two would be friends. I've also come across many scenes where Light seems to miss L.
Comment: original sources for your answer ?
Answer: When L confessed He thought of light as a friend I think on a conscious level it was simply a ploy, but there actually was some kindling of empathy. Also even though L admitted, 'I think I wanted you to be Kira' When he died he had a wide eyed expression seeing Light smile as if he had just been betrayed.
As for Light, he never seemed to portray much kinship for L. Nevertheless I think it would be wrong to assume he hated Light. In episode 36 near is wearing a mask of L, and you can hear Light thinking of how it is dishonouring L, which is really strange considering Light plotted his death.
I don't think L and Light were really friends, but subconsciously I think they both knew that under different circumstances they could've been, and I think that shone through when Light first brought L in from the rain.
Also in lights last moments when he's dying, he sees L. You'd expect him to see his dad as when people pass, they tend to have visions of those they have loved who have passed away. Instead he sees L, I think he really did care for him.
Comment: Interesting take but I'd have to disagree. Reading the manga, I don't get the feeling that Light cared for L at all.  Him seeing L at his last moments cannot be immediately interpreted that he cared for him. That was also not depicted in the manga so I don't think that was what the mangaka wanted to convey at all regarding L and Light's relationship.
Answer: No he did not think of L as a friend (beside when he lost his memories).Light was trying to make L think he was not kira and also light  tried killing L. i'm pretty sure he would of killed L if he would not be seen as suspicious if he did.
Comment: even if he did see light as a friend it would not be mutual   (In an interview he was asked, "Did L have any friends?" We are told, "No. When he told Light that Light was his first friend, it was a lie. L could never have a friend, as he found humans to be a very cunning species."Dec 4, 2015) http://www.deathnotenews.com/news/nathaniel-overthinks-death-note-the-friendship-between-l-and-light#:~:text=In%20an%20interview%20he%20was,be%20a%20very%20cunning%20species.%E2%80%9D
Answer: I personally don't see them as "friends"; both are fundamentally against each other when it comes to their perspectives.
But, that doesn't really mean they hated each other. There are hints that Light and L would have been friends under any other circumstances.
But, that's beside the point, the way I see it… Light and L have respect for each other. Light and L never really had a serious "game" with others before. Light saw in L a chance to prove his worth: if he won, he would be right, and if he lost, he would be wrong. This is evident in his slow decline into insanity as soon as L was out of the picture. With L being the best the world has to offer in opposition to him, he was to be a god, right?
So, ultimately what Light felt towards L was something you or I would feel towards a boss in Dark Souls. Respect. Begrudgingly or not, Light saw his equal in L (even though L is canonically  smarter than Light…), and once he was gone, he didn't feel as much excitement when going up against his successors, ultimately leading to his defeat. He never really gave them as much effort as he did to best L.
Again, this is my take on it.


How long should I sear meat after thawing from frozen state?

Question: I generally sous vide more food than I can eat at one time, so I put the extra food in a water bath and then freeze.  I'm wondering how long and at what temperature I need to sear meats after thawing to make sure they are hot but not overcooked.  I generally sear on the grill but sometimes in a skillet. Thanks!!!
Comment: Aren't you kind of losing the benefits of sous vide this way? If you sear it long enough to fully heat up, you're going to overcook the outside as badly as if you'd never used sous vide in the first place. Are you sure you don't want to reheat with the sous vide instead, and then optionally sear for texture?
Comment: I suppose it depends on why one is using a sous vide.  We mainly use it in order to precook a lot of meat for easy and quick reheating without sacrificing moisture and tenderness. Tonight I couldn't find the answer to my question so I just ended up doing what I thought was best.  I turned the grill up to high and seared  the meat for about 2 minutes on each side.  It worked great!
Answer: The Sous Vide Supreme website recommends reheating in the water bath for 45 minutes per inch of thickness (adding 30 minutes if reheating from frozen).  I would do this at a temperature equal to, or a degree or two lower than, your initial cook so as not to over cook.  Then sear or grill as normal...a minute or so per side.


Converting from Antlr3 to Antlr4

Question: I am in the process of converting an antlr3 to antlr4 grammar. I have stripped out all the syntactic predicates. I am struggling to make a correct conversion of this
    relaxed_date_month_first
  : relaxed_day_of_week? relaxed_month COMMA? WHITE_SPACE relaxed_day_of_month (relaxed_year_prefix relaxed_year)?
      -> ^(EXPLICIT_DATE relaxed_day_of_month relaxed_month relaxed_day_of_week? relaxed_year?)

to antlr4 grammar.Everytime the antlr4 tool runs into "->" character it says "extraneous input '->' expecting {TOKEN_REF, RULE_REF...ACTION}".
How do I fix this?
Answer: ANTLR4 has no tree-rewriting. So, remove -> ... entirely:
relaxed_date_month_first
 : relaxed_day_of_week? relaxed_month COMMA? WHITE_SPACE relaxed_day_of_month (relaxed_year_prefix relaxed_year)?
 ;

Comment: but this code doesn't show how to rewrite to a new tree. How can we do this ?
Comment: There is no way in ANTLR 4 to rewrite a (parse) tree.

Converting from Antlr3 to Antlr4


What are the common tennis terms in Korean?

Question: Particularly for

advantage set / tiebreaker set
game
set
match
love (the term used for 0 or a no score situation)
15/30/40
deuce
advantage in / advantage out
Answer: We commonly use English loanwords when it comes to sports.

advantage set / tiebreaker set : 어드밴티지 세트
game 게임, 경기
set 세트
match 매치, 경기, 시합
love (the term used for 0 or a no score situation) : 러브게임, 무득점 경기, 러브 ex) 이번 게임은 러브로 끝났다.
15/30/40 : 0(love), 15(fifteen), 30(thirty), 40(forty)
deuce : 듀스
advantage in / advantage out : 어드밴티지 인, 어드밴티지 아웃.
Answer: I believe most Korean use the tennis terms in English when playing tennis. I've been playing tennis with my Korean and American friends, but I have never used any terms in Korean.


I found a solution but can't post due to low reputation

Question: I found that the Random Select by André Berg script mentioned in this post is no longer downloadable. So I created my own script to select random objects in Adobe Illustrator. You can find it here. https://ksoftlabs.com/select-random-objects-in-adobe-illustrator/.
But cann't share it in the original post as I don't have enough reputation. How can I share this with the community?
Answer: Go to the answer with the script and hit the edit button. You can then edit it to include this information. Because of your rep it won't show up immediately but will enter a queue for approval.
Be sure to mention you wrote the script as part of your edit. StackExchange requires such things be disclosed.
Answer: Thanks for posting!
I just went ahead and updated my answer with a link to the script on a GitHub gist.
Answer: If you have found a solution, you can post it as an answer to your own question.


How to monitor API requests by user / connected app?

Question: We have clients that access Salesforce API to write data and read data using the salesforce standard APIs. How do monitor the traffic, logs for these API calls? I'm also looking for ways to know the traffic by username or clientId (connected app).
Comment: did you look into Event Monitoring? A OOTB extra cost SFDC feature
Comment: Yes, but the 24hrs time period may not work. I need to look at the hourly log, but even that may not help much with our requirement.
Answer: Winter 20 announces near real time Event Monitoring and this includes ApiEvents and UriEvents
In both event types, you have access to the URI, client IP address, and SFDC UserID of the running user (among other fields such as statistics on run time)

Available to customers who purchased a Salesforce Shield or Salesforce Event Monitoring add-on subscription. To view or manage events, enable the View Data Leakage Detection Events user permission.


A sequence of subsets of an infinite group

Question: Is there an infinite group $G$ such that there is not any sequence $(A_n)$  of its subsets such that always
$$A_n=A_n^{-1}, \quad A_{n+1}A_{n+1}\subsetneqq A_n$$
?
link
Comment: Such a group has to be torsion.
Comment: @Misha I'm not sure of any link with approximate groups, which involve a parameter and finite subsets. On the other hand there should be a link with non-topologizable groups.
Comment: A related question: http://mathoverflow.net/q/179177/24165 .
Comment: It's equivalent to say that $A_{n + 1} \subsetneq A_n, A_{n + 1} A_{n +1} \subseteq A_n$, by going through $A_{2n}$.
Comment: I am not sure of the equivalence.  I think closure under inverse is important (consider riffs on N under min).
Comment: Clearly all $A_n$ contain $1$ and $\bigcap _{n}A_n$ is a subgroup.
Comment: It seems that the question is related to the concept of "approximate groups". Alas, I do not know much about the area, but Terry Tao might be able to say something interesting.
Comment: Masked Avenger: yes, I meant to include that; I meant to replace only the second condition (i.e. we have $A_n = A_n^{-1}, A_{n + 1}A_{n + 1} \subseteq A_n, A_{n + 1} \subsetneq A_n$.
Answer: Here an extended comment. Call Property (P) the assumption of non-existence of such a sequence, so that the question is whether there exists an infinite group with (P)
My comment is the observation that if such a group exists, then it can be chosen to be finitely generated with all its proper subgroups finite ("quasi-finite").
Indeed, a group with Property (P) satisfies the following 2 properties:

it admits no nondiscrete Hausdorff topology "non-topologizable"
it's artinian (or min): it admits no properly descending chain of subgroups

Moreover Property (P) passes to subgroups.
Now I claim that if $G$ satisfies (P), then it contains an infinite quasi-finite subgroup: indeed if $G=G_0$ is not quasi-finite, then it admits a proper infinite subgroup $G_1$, and by induction we define a properly descending chain of subgroups, which has to stop, i.e. we eventually get a quasi-finite subgroup (hence with (P)).
Now a quasi-finite group is either finitely generated, or is an abelian Prüfer group $\mathbf{Z}[1/p]/\mathbf{Z}$ (Hall-Kulatilaka), but the latter is topologizable as we see by embedding it densely in the Lie group $\mathbf{R}/\mathbf{Z}$. Hence the resulting quasi-finite groups with (P) have to be finitely generated.
To conclude, the question boils down to whether there exists an infinite, quasi-finite, finitely generated group with (P).
Comment: I think `it admits no nondiscrete Hausdorff topology` is equivalent to `it admits no nondiscrete metric`. It seems such a group cannot have an infinite chain of (normal) subgroups. It suggests to me (somehow) that Hausdorffness may have a better substitution. Btw, I hope I can find a relation to Banach measure.
Comment: I'm not sure what you mean by "no nondiscrete metric". What do you require about the metric?
Comment: I'm not sure but if there is a sequence of neighborhoods of $1$ which make a base around $1$ in a group topology the topology must be pseudometrizible. If Hausdorff, then metrizable.
Comment: OK, but once we are reduced to finitely generated quasi-finite groups, this discussion is of little relevance.
Answer: This is a partial answer. There exists an infinite group $G$ having no sequence of subsets $\{A_i\}$ such that
$$
A_{n+1}A_{n+1}\subsetneq A_n,
\quad\hbox{and}\quad
\bigcap A_i=\{1\}.
$$
(We omit the inverse condition but add the the intersection-triviality condition.)
Indeed, such a sequence defines a Hausdorff topology on the group where $A_i$ are neigbourhoods of $1$ and all other points are isolated. The multiplication is continuous at $(1,1)\in G\times G$ with respect to this topology. It remains to note that infinite locally non-topologizable groups do exist.


free up space on iphone

Question: Hi I have couple of questions regarding space on my iphone 5s, IOS 10.2
Q1) available space shown in my iphone (2,93 GB) is different than what shown in Itunes when I connect it to mac (3,5 GB). Any explanantion? what to do?
Q2) In my Storage & iCloud Usage > Manage Storage, I have around 1,16 GB used space by messages. However, I have deleted all messages from all my apple products. How do I delete that? I have almost try everything advised on internet. This might be related to question 1.
Q3) when I connect my iphone to mac and open Itunes, in movie section from left side, I have a video that I do not know how to delete it. how to delete?
Q4) every now and then, 3 deleted videos and a picture, show up in my photos on iphone. No matter how many times I have deleted them, they keep showing up like once every 3 days.
Comment: This site works best when you focus on 1 question at time.  See [ask] for info on how structure and ask good questions that will have a chance at being answered.
Answer: There are a few ways you can clear up space on iOS. First of all, there are apps on the iTunes Store that clear up junk on your disk. I used one of these and it opened up 4GB without deleting anything that I noticed. You can also delete browsing data by going into Settings > Safari > Advanced > Website Data. Scroll down to the bottom and click 'Remove all Website Data'. You can also just delete data. There are some others, but there are just a few.
I know this doesn't answer all of your questions but hopefully, it helps some.

free up space on iphone