How can i get rid of m2_cl tables which are created in my Database

Question: We have outsourced a Magento developer to migrate M1 website to M2, this process is going on since few months now, suddenly since few day my Website is loading super slow, I checked all aspects but nothing actually worked. The Ram usage is suddenly increased by a lot, I tried deleting that new website + its database but still no fix. I tried deleting all the m2_cl tables which are newly created because of the data migration tool, then my website worked smooth for some time and crashed, after restoring it back it was working fine for some time and then again back to the issue. If anyone know how can I remove M2_cl tables safely. This might fix the problem.
Answer: Be aware! _cl tables are NOT related to M1 to M2 migration, but to M2 reindex process.
See here an useful answer: Magento 2 Tables Being Created Ending in "_cl"
Comment: The tables referred to in the question have names that start with 'm2_cl', and are created as part of the Magento 1 to Magento 2 migration. Tables with names that end with '_cl' are not related to migration.
Answer:
php bin/magento migrate:delta -a path to config.xml

once your incremental chnages done then run reindex command it will remove automatically
Comment: Can you pls explain me in detail, the steps and our free lancer developer who was working on this project has left us & I need to figure  a way out to remove those tables.
Comment: you have run this command on server where your data migration tool  is
Comment: I am restoring the new website folder which I deleted to check the website performance. Once its restored I need to check the data migration tool.


Word for purposeful misnomer

Question: I've been looking for a word all day with a very specific definition, It is very similar to a misnomer, yet intentional and usually through unreality to describe something humorously, E.g. "Horse tornado" as a word for carousel or "Cold house" as a word for fridge.
This is a very specific word. The closest I've come is misnomer, or something similar to the opposite of folk etymology, But I'm not able to find anything more specific due to horrendous google search results
Comment: Does this term only apply when the individual say "get on the horse tornado" just to be funny, or can you also use it to describe the situation when the person has forgotten/doesn't know the proper term?
Comment: I believe the definition is more applied to the specific disconnection from reality instead of using a simpler term rather than mistaking the term.
Comment: If it applied in cases where the person forgot or was trying to be euphemistic, I'd call it a [*circumlocution*](https://en.wikipedia.org/wiki/Circumlocution), but I don't know of a term that emphasizes the fantasy aspect.
Comment: Are you looking for a term for a one-off invention, or for a *euphemism* that was recalled?
Answer: The nature of impossibility (unreality) is captured with the literary term
CATACHRESIS

CATACHRESIS (Grk. "misuse"): A completely impossible figure of speech
or an implied metaphor... For instance, Hamlet says
of Gertrude, "I will speak daggers to her." A man can speak words, but
no one can literally speak daggers. In spite of that impossibility,
readers know Shakespeare means Hamlet will address Gertrude in a
painful, contemptuous way.
-Carson Newson University.

and I would say fits your first example:

horse tornado

As a horse cannot be a tornado, nor a tornado a horse ; yet in the context of a carousel the imagery is meaningful and still makes sense, much like the yoking of speaking and daggers, should not make sense, yet it does.
Comment: Note that this term is also used by lexicographers. The OED defines *catachresis* as "Improper use of words; application of a term to a thing which it does not properly denote; abuse or perversion of a trope or metaphor." They have entries marked *catachrestic*, which means "Of the nature of catachresis; wrongly used, misapplied, wrested from its proper meaning." I'm not sure that it's meant to be deliberate.
Comment: Interesting thanks for the further information @tchrist. On the deliberateness of the technique, I would say the above link implies it can be, as they cite Shakespeare's "speaking daggers" as an example of Catachresis, and I doubt they imagined Shakespeare used the technique in error :)

Word for purposeful misnomer


spacelike and timelike event or interval?

Question: Just a short question:
Is it valid to say that some event is space/time-like or is this term reserved for the distance between two events (the space-time interval) and four vectors?
Comment: an event is a point in an affine space. How would you define its length?
Comment: it is still the distance between two events: the event you are trying to measure and whatever event defines the origin
Comment: Ok, that's  what I wanted to hear. On the other hand, a single event can be represented by a four-position, so that its lenght is the distance from the origin or am I wrong?
Answer: The terms spacelike, timelike, and lightlike refer to space time intervals only. They are used when discussing the sign of the distance between two different events. Mathematically, this comes from the sign of the metric tensor acting on two different four-vectors, $g(\mathbf{x},\mathbf{y}) = g_{ij}x^i y^j$. The metric tensor applied to a single four vector (event) will not return a number, but rather a covector. Hence, it does not make sense to talk about the sign of the metric tensor applied to a single vector.


run the same hosts on my local network?

Question: I don't know how to explain that but I want to do the same like if I got in my hosts file any host to resolve but in a network scope. when the try to access to some website like http:///www.google.co.uk/ they redirect to my local web server.
Comment: Do you mean that for any device on your network, if someone tries to go to google.com, they instead go to your webserver?  Would this be for all sites, or just a few?
Answer: In your router you will have a route like this: destination 0.0.0.0 gateway 22.214.171.124 (your network may be different). Change the destination address to the local webserver you want your traffic to point at.  Keep in mind this change will keep any traffic from leaving your local network, effectively cutting internet access to your network.  This may or may not be possible on your router depending on how advanced it is.  In the end you are changing your routers default route.

run the same hosts on my local network?


How do I use fetch_feed() to pull in a large number of posts?

Question: When I use fetch_feed() to pull in posts from a feed, even if I set the maximum posts variable to a very high number, it will only pull in 10 posts. I want to pull in all the posts and then paginate the way I would for my regular blog posts. I thought maybe it was set to the number in my Reading settings, but I changed it to 30 with no change. There are definitely more than 10 posts in the feed I am trying to pull in. Is this possible or is this inherently limited for this function?
Answer: If someone happens upon this and doesn't have the option to change the feed length, my solve was to use an array of feed pages:

fetch_feed( array('http://example.com/feed/', 'http://example.com/feed/?paged=2', 'http://example.com/feed/?paged=3') );
Answer: from wordpress codex: http://codex.wordpress.org/Function_Reference/fetch_feed
<code>    // Figure out how many total items there are, but limit it to 5.
$maxitems = $rss->get_item_quantity(5);

// Build an array of all the items, starting with element 0 (first element).
$rss_items = $rss->get_items(0, $maxitems);
</code>
change the $maxitems to whatever you want. hope this is what you were looking for.
Comment: Thank you, but I should have been more clear. What I meant by "even if I set the maximum posts variable to a very high number, it will only pull in 10 posts" was that I changed `maxitems = $rss->get_item_quantity(5);`  to `maxitems = $rss->get_item_quantity(99);` This didn't change the number of posts.
Answer: It sounds like your source feed is showing only 10 posts. So, regardless of what you pit for get_item_quantity, only 10 posts will show, max.
If you're pulling posts from a WordPress site, you can adjust how many posts are included in the RSS feed in Settings -> Reading.
Change this value: "Syndication feeds show the most recent"


Is blue drywall enough behind shower wall tiles?

Question: We live in Texas. My builder Highland homes just used blue drywall that too just till 12 ft for shower walls. No cement board between tiles and blue drywall.I asked him and he says everything is perfect as is. I checked the contract. It says '1/2" Denshield (or equivalent) board on shower/tub walls'. Is blue drywall considered an equivalent board?
Comment: Also: [Green board with waterproof membrane](https://diy.stackexchange.com/questions/193422/green-board-with-water-proof-membrane), [Tiling on Drywall in Shower](https://diy.stackexchange.com/questions/178956/tiling-on-drywall-in-shower), [Should a tiled shower ceiling have cement board instead of drywall?](https://diy.stackexchange.com/questions/243676/should-a-tiled-shower-ceiling-have-cement-board-instead-of-drywall)
Answer: I would not consider blueboard to be equal to DenShield.
Have the contractor provide the proof in writing, or demand that the blueboard be replaced with Denshield.
Also do not make any more payments until you are satisfied.  If there is a financial institute involved, tell them that you request no draw be released and why.
Answer: Pretty much what RMDman said but maybe a bit more specific.  "Blue board" is for plaster veneer application.  It is not intended for wet environments like a shower stall or bathtub surround.  If you look at the spec sheet or tech guide for a specific blue board product, they should say not to use it for tile application.  For example, from the Home Depot site, the spec sheet for USG blue board states the following under limitations.

IMPERIAL Brand Gypsum Bases should not be used in areas exposed to excessive moisture for extended periods or as a base
for adhesive application of ceramic tile (SHEETROCK ® Brand Gypsum Panels, Water-Resistant, or DUROCK ® Brand Cement
Board are recommended for this use).

That said, there are waterproofing systems like Schluter Kerdi that can be used over regular drywall.  That one is expensive so your builder is probably not using that but there could be some lower price alternative.
From the sound of it, they're probably just putting the tile directly onto the plaster veneer base gypsum boards.  That is bad.  Stopping payments etc as the other answer says is not inappropriate unless you're fine redoing it later.  I would personally try to get out of dealing with that builder (if they're doing this, there are other problems as well) but that may not be an option for you.
As an additional note, because you say

No cement board between tiles and blue drywall.

Cement board itself is not waterproof.  It is not damaged by water itself but it will still wick it up and transfer it to whatever is behind it.  If you were to put some cement board over gypsum or even over bare wall studs, there would still need to be some moisture/vapor barrier like plastic behind the cement board  or liquid-applied membrane over the top of it.
Comment: Maybe the op meant purple board.
Comment: @ErikFriesen I'm responding to the question he asked, not the question he may have meant to ask, and purple board is not suitable for setting tile in the shower either.
Comment: I agree it's not suitable but is very common. To stop payment when 95% of contractors in a region do it that way isnt always the best route.
Comment: @ErikFriesen Contract says DensShield or equivalent.  DensShield is gypsum with a waterproofing layer specifically designed for wet area tile.  Purple board is not designed for that application and manufacturer literature will say so explicitly so it is not an equivalent.  Something being a _common_ cop out does not make it acceptable.  Whether that's a battle the OP wants to fight is a decision for the OP.


Which aircraft would be effective in medieval times?

Question: Based slightly off the anime GATE, if I had excess to modern military technology and an army to operate them in medieval times like the anime, which aircraft would be better suited to destroy a city?lets say the modern army already has a base built at the medieval land and they have a good supply line. The only thing to worry about now is to figure out which aircraft out of the two would be most effective to be used by the army
Comment: Which one of those uses fuel you'd have access to?
Comment: Effective in what sense? The number of people they can kill? Travelling long distance quickly? Transporting and deploying troops in the battlefield? Flying over and providing recognisance? Also, what are the requirements for a 'good' answer? I think this may be closed for being too oppinion based or for being unclear what you're asking.
Comment: For anything, the concept of "better suited" strongly depends on the use case. A knife can be better suited at slicing meat, but for eating a soup is quite useless. Unless you define the use case, there is no way to answer this question
Comment: You need to make the question standalone: Non one should be required to look up the anime you reference, so you'd need to make some things clear: must the aircraft be refuelled, landed, repaired, ertc in medieval setting (i.e. no runway...)? What is the aircraft supposed to accomplish? Will it need to destroy things randomly, or be a reconnaissance craft, or be the support of some troops (what kind, what mission?)? Will there be more than one? What range and mission-times are required? Will there be other high tech stuff on the side of the opposition? ...?
Answer: I haven't seen the anime, but I would argue the biggest problem would be fuel and ammunition and spare parts (and to an lesser extent lubricating oil). They should pick the most primitive planes they can find, a helicopter is waaaay to complicated to use in medieval times. I would suggest World War 1 fighter planes, or maybe at most a World War 2 (propeller) fighter plane. A WW1 fighter can probably run on simple  vegetable oil or alcohol and they can even fix broken wooden wings. They can drop primitive medieval grenades or even make ammunition for the fighters gun.
Answer: Given that a fighter jet is mainly built to attack other aircraft while an attack helicopter is mainly built to attack ground targets, the attack helicopter is the obviously correct answer.

A factor is available fuel, unless the army has large reserves of modern fuel. Many helicopters use diesel oil, which might be easier to produce than jet fuel. It might even be possible to produce biodiesel from local farm products.
Answer: How many other airplanes you need to FIGHT in the air in those times?
Or do you would need to ATTACK something? Like a castle, army or similar?
Not to mentions that for helicopter to operate you need a patch of land without trees slightly bigger than the size of rotors. For a Jet you need a large airstrip that would be flat and strong enough for a jet to take off.


In M-theory, are strings created by membranes?

Question: In M-theory there are 2- and 5-branes, but where are the one-dimensional strings which are responsible for all the particles?
Can 5-branes turn into 1-dimensional strings due to compactification?
Answer: The fundamental String of IIA String theory is the M2 brane of M-theory wrapped on the M-theory circle at weak coupling limit.
The weak coupling limit is when the radius of the compactified circle is very small.
More generally at weak coupling limit the best description is the IIA string theory while at strong coupling limit the M-theory description.


uc-logic tablet

Question: I want to use my uc logic wp8060 tablet on linux. I downloaded and installed wizard-pen driver. When I do a lsusb, it does show with the right model. when I move the pen, nothing happens. And I have new battery in it
Comment: This question is also related
http://askubuntu.com/questions/547041/pen-tablet-mousepen-doesnt-work-in-ubuntu
Answer: I recommend using the driver from http://digimend.github.io/ (old wiki at http://digimend.sourceforge.net/wiki/DIGImend ). They recommend against using the wizardpen driver generally. I'm using a modified version of their driver for my Huion h610 successfully, for whatever it's worth.

uc-logic tablet


Creating a Windows XP Professional PE USB ISO on Linux

Question: I am attempting to create a Windows XP PE ISO on Ubuntu 16.04. So far the best way I found was the apparently popular Gandalf PE version that I downloaded and burned to USB.
I am using UNetbootin as software on Ubuntu to burn the ISO file. The ISO I selected was the latest available: http://windowsmatters.com/2016/11/08/gandalfs-win10pe-x86-redstone-build-14393-version-11-07-2016/
But when I insert and boot from USB on the computer that contains Windows XP Professional, it says that there is no boot file on the USB, and starts booting normally.
I am not sure what I am doing wrong, but does anyone have experience creating a bootable USB ISO with Gandalf on Ubuntu, to boot on a different computer?
What I need is command prompt access, to reset the Windows password.
Answer: You should be able to download chntpw from your repo. With access to the physical volume, this will reset/clear your password from a linux environment.
Comment: I am you be more specific for those readers less familiar with Linux than you are


Will clothing effect a baby's S.P.E.C.I.A.L.?

Question: So I've been playing Fallout Shelter for 2 days now and was wondering if the clothing on dwellers affect the baby's S.P.E.C.I.A.L. For instance if both of the parents have average S.P.E.C.I.A.L. (like everything is 1 or 2) but when I put a certain clothing (for example) intelligence and  perception goes up. Will the baby have a higher chance of having one or both of those stats higher?
Comment: Please don't add the game name to the title as we can clearly see what game it is through the tag.
Comment: Ok I just really need an answer, my vault is progressing faster than I thought.
Comment: Actually game title in the question title is completely fine. This was discussed a while back. Its also fine to edit the name out of the title, providing it is not all you do. For the user that undid the edit on SPECIAL, SPECIAL is an acronym. As such, it is properly displayed with full stops after each letter.
Comment: This is also how it is usually displayed ingame
Comment: No, there's no standard for how SPECIAL is spelled. For example, in the in-game help file, it's spelled SPECIAL. You're spelling it SPECIAL in these comments. Most importantly, acronyms aren't typically spelled with periods in them these days. No one writes L.A.S.E.R. or A.T.&T.
Answer: Based on some testing in this reddit post, the stat increases from clothing do not seem to affect the inheritance.
Answer: I am late on this topic but figured I'd add some more context. As being already answered in short, no clothing doesn't affect a baby's stats. Only the actual stats from parents will be passed on to the offspring.
In addition, it seems to be a random pick between fathers or mothers max stat that is inherited. I have been playing for quite some time now and 1 out of 10 babies have inherited the fathers max stat in my playthrough in which I do not intertwine relations (same mother/father for all kids in specific family).
Keep in mind this is 2022 updated client.


Social Networking backend architecture

Question: Ideally, where would an application like Facebook store its "Friends" data?
In a database table? in an xml file?
Comment: pretty sure something the scale of Facebook doesn't use a single database, much less a single table to store anything much less an xml file.
Comment: This is extremely close to http://stackoverflow.com/questions/1009025/facebook-database-design
Answer: From Facebooks engineering page:
"Already, we are the second most-trafficked PHP site in the world (Yahoo is #1), and one of the largest MySQL installations anywhere, running thousands of databases."
and
"We've built a lightweight but powerful multi-language RPC framework that allows us to seamlessly and easily tie together subsystems written in any language, running on any platform. Facebook is built in PHP, C++, Perl, Python, Erlang, Java, and even a little bit of ML—and it all works together.
* We are the largest user in the world of memcached, an open-source caching system. Originally developed by LiveJournal, we've since made so many scalability improvements and performance upgrades that we will be the primary contributor of features in the next major release.
* We've created a custom-built search engine serving millions of queries a day, completely distributed and entirely in-memory, with real-time updates."
Answer: Relational databases?
Answer: check out this blog: http://highscalability.com/ many real-world examples of systems architecures to learn from
Answer: "Friends" data is well-described in a graph database.  Neo4j is an example, though I know it's not the way Facebook stores this information.
Facebook uses a number of database technologies that may be involved:

a patched version of MySQL
Cassandra
Hadoop
... others
Answer: Most probably it should contain some other mechanism. As an example a search engine does not keep its index as a database or XML file. To obtain a maximum performance generally they keep some tree (Binary search tree or more complicated one) and store them on disk in performance effective manner. So I guess such mechanism.
Answer: Certainly not in a XML file.
Yes, in a database, in one or several tables. And for the precise exemple of facebook, on several server.

Social Networking backend architecture


Is it possible to change Field Level Security with Workflows

Question: How can I show a hidden field to a user after triggering a workflow which will evaluate on certain condition and will decide either this field need to be visible or not?
Answer: You cannot change field level security by a workflow. However, you could do something like this:

Create a new record type for your object
Create a new page layout (on which you show this specific field) and assign it to the record type
Create a workflow rule based on your criteria + field update that changes the record type
Answer: No its impossible to change field level security by workflow. @robin but i doubt your 3rd point since field should be hidden before workflow fire and you mentioned to include in pagelayout. ok but workflow only update field it doesn't hide or show field .and if you put hidden field in page layout than Superman condition is not fulfill
Workflow automates the following types of actions:
Email Alerts—Send an email to one or more recipients. For example, automatically send sales management an email alert when a sales representative qualifies a large deal.
Tasks—Assign a new task to a user, role, or record owner. For example, automatically assign follow-up tasks to a support representative one week after a case is updated.
Field Updates—Update the value of a field on a record. For example, automatically change the Owner field on a contract three days before it expires.
Outbound Messages—Send a secure configurable API message (in XML format) to a designated listener. For example, automatically initiate the reimbursement process for an approved expense report by triggering an outbound API message to an external HR system.
Comment: The field update should update the **record type**, not the field in question. This update will make sure a different page layout is shown, on which you can show the field.
Comment: @RobinDeBondt just to make my issue bit clear. I want to implement a functionality in which a user will ask a question and will save the answer of that question in salesforce. On answering the question workflow will compare the answer of the user with the original answer. And if it will be correct answer will be revealed to that particular user. And will remain hidden for rest of the users.

One idea that came into my mind is I use 'Field Update' with some static text in the field and update it after the workflow. I think this can work.
Comment: Could you use a Formula Field somehow to solve that? If the Answer and Solutions match than in the Formula Field display the "Correct" or similar output.


How to fix the weird surface in fluid object

Question:
Hi Guys, this is my first time to make a fluid simulation. However, I got some problem. The surface looks so weird. I am trying to make an animation so I do not decide to use sculpt mode to fix it. Is it any other method to fix this problem
Comment: What does it mean "face looks so weird"?
Answer: The issue is caused by insufficient domain voxel resolution. If you don't want to do high resolution such that these artifacts are not visible, you can:

smooth it with sculpting manually, but this is only viable for still images, this will be very time consuming for an animation.
design the fluid in such a way it will fully intersect with the inner surface of the glass. Then you can create a special mesh that represents the glasses inner volume and do a boolean intersection with the fluid. The problem is that a fluid simulation can lead to some non-manifold meshes (water droplets joined in single vertex where the voxels meet) and the boolean operation in Blender will fail for some frames. You can apply some smooth to the fluid with modifiers before the boolean one - this should further mitigate the problem of failing boolean, but it does not solve it completely. You can correct the failed frames manually, or use another software that has more robust boolean algorithms to do non-manifold booleans (CGAL, Houdini, ..).
Answer: Mr Zak: I think Justin_bob is referring to the "blockiness/aliasing/staircase-steps" of the fluid at the fluid/curved glass interface.
I believe the best way to correct this problem would be to use dynamic paint to smooth out the fluid (assuming you're using a sufficiently high resolution) at the fluid to glass interface.
Johnathan Williamson from CGCookie explains the technique at:
https://www.youtube.com/watch?v=Avos5B5H6E4


Crystal Report - How to deal with empty data?

Question: I have sub report linked with EmployeeID. But for some employees I don't have data so report get suppressed. And I get record at wrong place. I want to avoid this so what can I do ?
Answer:
I get record at wrong place

What do you mean the wrong place? Don't you mean the sub-report is taking up space when there are no records for an employee?
It depends on the sub-report layout, but I usually make the sub-report very thin in the main report and then I'll set suppress formulas in the visible sub-report sections. That can be done with an isnull() check on some key. I think there is also a special keyword you can use to check if there are records, I forget the name though.
Answer: You should be able to use the section suppress option on all the sections of the sub-report. I believe you can tie the section suppression to a formula. In that formula you need to check against the record count variable(I forget the exact name) and return a boolean in that formula to show/hide the given section.


How do you describe a quantum field theory state?

Question: Intuitively, quantizing a field implies that there exists a probability for each state of the field denoted as
$$\Omega[\psi]$$
So the vector $|\Omega\rangle$ must be a superposition of all possible field states weight with an amount relating to probability
$$|\Omega\rangle=\Omega[\psi_0]|\psi_0\rangle + \Omega[\psi_0+\delta\psi]|\psi_0+\delta\psi\rangle+\Omega[\psi_0-\delta\psi]|\psi_0-\delta\psi\rangle+...$$
$$|\Omega\rangle=\Omega[\psi_0]|\psi_0\rangle + \sum_{n=1}^{\infty} \left[ \Omega[\psi_0+n\delta\psi]|\psi_0+n\delta\psi\rangle + \Omega[\psi_0-n\delta\psi]|\psi_0-n\delta\psi\rangle\right]$$
Or written with integral notation
$$|\Omega\rangle=\int d\phi \, \Omega[\psi_0 + \phi] |\psi_0 + \phi\rangle$$
Is this the correct formula for the field state and is there any other way of writing the field state in terms of any other basis like energy, particles, and other properties.
Comment: This is called the Schrodinger functional representation, but it's rarely used for computation. A standard introductory QFT book is all about the particle basis for the free 'in' and 'out' fields.
Comment: @RichardMyers I've got "Quantum Field Theory: A Modern Introduction" by Michio Kaku, and It doesn't give enough satisfying answers to this question. I'm asking on here because I'm self-taught and books are quite expensive.
Comment: The answer to this sort of question will appear in the first couple chapters (if not pages, historical notes aside) of any quantum field theory textbook. You're more likely to get a detailed (and correct) picture of what's going on from any of those sources than here.

If you would like references, the standard is Peskin and Schroeder, but there are many many others with varying levels of detail on any given topic.
Comment: The sum in your third equation doesn't really make sense since there's no way to reach all field configurations by moving in fixed steps $\delta \psi$ otherwise this seems accurate if not computationally useful.
Comment: @jacob1729 What would be the correct way to write it? Also, how would you write it in a different basis such as the number of particles?
Answer: Particles should be identified with states in the Hilbert space that transform in unitary irreducible representations of the Poincaré group. Single- and multi-particle states are eigenstates of the momentum operator $\hat P^\mu$, with $\hat P^\mu \vert X \rangle = p^\mu \vert X \rangle$ for a set of real numbers $p^\mu$ with $p^0 \gt 0$ and $p^2 \ge 0$, which transform in the 4-vector representation of the Lorentz group. Single-particle states $\vert X \rangle$ transform under unitary irreducible representations of the Lorentz group as well, as $\vert X \rangle \to exp (i \theta_{\mu \nu} S^{\mu \nu}) \vert X \rangle$ where $\theta_{\mu \nu}$ are the boost and rotation angles and $S^{\mu \nu}$ are the generators of the Lorentz group in the representation of that particle. The vacuum $\Omega$ is assumed to be Lorentz invariant and to have zero momentum: $\hat P^\mu \vert \Omega \rangle = 0$.
The completeness relation is
$1 = \sum_X \int d \Pi_X \vert X \rangle \langle X \vert$
where the sum is over all of the single- and multi-particle states $\vert X \rangle$ and
$d \Pi_X = \prod_{j \in X} \frac{d^3 p_j}{(2 \pi)^3} \frac{1}{2 E_j}$
Quantum fields are operators and are defined as integrals over creation and annihilation operators, respectively $a_p^\dagger$ and $a_p$, for each momentum
$\phi (x) = \int \frac{d^3 p}{(2 \pi)^3} \frac{1}{\sqrt{2 \omega_p}} [a_p (t) e^{-i p x} + a_p^\dagger (t) e^{i p x}]$
where
$x = (\vec x, t)$
$signature = (+, -, -, -)$
$a_p^\dagger \vert \Omega \rangle = \frac{1}{\sqrt{2 \omega_p}} \vert p \rangle$
and $\vert p \rangle$ is a state with a single particle of momentum $p$.
You have $\phi (x) \vert \Omega \rangle = \vert x \rangle$, that is $\phi (x)$ creates a particle at position $x$.
Note: In QFT the symbol $\Omega$ is reserved for the vacuum state in an interacting theory.


How do I exclude a promo code to a free shipping shopping cart rule?

Question: I am trying to exclude a specific promo code from receiving free shipping. The free shipping is also a shopping cart rule.
Comment: specify magento version
Answer: First, you need to ensure the priority of each rule is set appropriately (this should be under the first tab or section when editing the rules).  Make sure the free shipping rule has a very low priority.  Higher numbers are lower priority (eg 2 is lower priority than 1).  0 would be the highest priority (and happens to be the default priority)
Next, under the "Actions" tab/section, check the box for "stop processing other rules" (in M2 it is called " Discard subsequent rules") on the promo that you don't want to allow free shipping on.  This will cause Magento to stop checking rules for matches if it matches on that promo.


Andy Android Emulator Windows 8 issue

Question: About a month ago, I loaded the Android emulator "Andy" on my windows 8 laptop and it seemed to work fine (except it kept kicking me out of Clash of Clans after a couple minutes, but the emulator kept running).
Yesterday, something happened.  While in Clash of Clans, the background turned all black and just the small images were visible.  This has happened before and I would kill Andy using the X in the upper right corner.  I would then restart Andy and things worked OK again.
However, yesterday when this happened, I killed Andy in the same way, but when I tried to restart Andy the frame would display for a second or two and then go away.
I figured that a bit got twisted somewhere, so I uninstalled that version of Andy and downloaded and installed a newer version, but I get the same results.
I checked the web and the closest I came was "Andy won't launch on windows 8".  The suggested solution was to roll back the display driver.  I did that with the same results.
I figure that there may be a flag somewhere that thinks Andy is running, so it shuts down any new version, but that is just a guess.
Has anyone else run into this problem?
If so what was the solution?
Answer: Try to change the compatibility setting to windows 7/8

Andy Android Emulator Windows 8 issue


Wifi channel selection

Question: Is it possible specifically select a Wifi channel use? I am defaulting to channel 6 which has a low signal to noise ratio.  "Wifi Signal", ver 1.3 suggests that several other channels offer better qualities.  Is there a way to move another channel?
Comment: This is something that would need to be set within the WiFi access point itself. Please edit your question to provide information on what router or other WiFi access point you are using.
Comment: I was about to put this same thing into the answer, but you beat me to it. :-)
Answer: Many wifi access points look for the quietest band, and start on that.  Your computer when it isn't connected essentialy listens on 1, then 2, then 3, then 4...
It creates a list of all the ones it finds, then presents the list to you.
Some WAP's also can be configured to set a particular channel.  In addition you may be able to change the default power setting.
My experience has been that WAP location and antenna orientation have far more to do with SNR than channel number.  If this is a home network, you may want to look at putting a WAP at opposite ends of your house.  If you do this, only ONE of them serves DHCP requests.  Or both serve to a central computer.  Or you set all local addresses manually.  2 DHCP servers is a pile of grief.
To formally answer your question:  At the client end, no it is not possible.  At the WAP yes it is possible.
Hope this helps.

Wifi channel selection


Can you sue a person for time spent taking them to court?

Question: I know legal proceedings can be time consuming and stressful. Can a plaintiff sue the defendant for the time and energy involved? Would they need to show something, for example taking time off work to attend a hearing?
Comment: Possible duplicate of [Do courts award legal costs to successful pro se litigants?](https://law.stackexchange.com/questions/36127/do-courts-award-legal-costs-to-successful-pro-se-litigants)
Comment: It's close, but I see a distinction between the two questions. This question is asking one lawsuit giving rise to a new one seeking damages for emotional distress, etc. The previous question asked about awarding costs as a sanction in the case in which they were incurred.
Comment: @Nij this question does not even say the person is _pro se_. OP could still mean having a lawyer representing them. How can this be duplicate?
Comment: If this was the case in all lawsuits, it would simply result in every lawsuit leading to an infinite loop.
Answer: Common law countries -- such as Canada -- do not usually allow these types of actions. There may be exceptions for "abuse of process" cases, in which the plaintiff generally alleges that the other party was pursuing the litigation in bad faith.
Comment: Oh, I think I misread the question. No, you can't sue someone and then sue them more just because you chose to sue them. As long as they comply with the applicable rules of court, I can't imagine you could do anything about the time involved. If they're acting in bad faith simply to drag out the process, though, you could ask the court to impose sanctions.
Comment: How is abuse of process applicable here? From my understanding it usually works the other way around, when the plaintiff starts legal action without proper reason to do so. I am very interested in any legal concept where one party does not make an honest effort to resolve things but instead wastes time.
Comment: Ok I'll ask a new question worded differently


What happened to Harrison's first nanny?

Question: In Dexter Season 5 Harrison's nanny looks like an important part of the story. She is the only one who passed the nanny interview held by Debra. She really even cares for Harrison. So why did she disappear in the start of season 6 ? I am unaware if it's mentioned later.
Comment: according to the dexter wiki she left the series with no in universe explanation. And there was no mention why Batista's younger sister Jamie took over the role as nanny.
Comment: @Jared you can post it as an answer with the wikia link you are telling about.
Comment: It doesn't matter--she was very good, and falls into the category of "forgotten character" Showtime dropped the ball, just as they did for the show in the final season. So many wonderful endings that could have been, for this wonderful show. But you notice all the "new Directors" getting their decorations towards the end, sort of came across as "to hell with the audience and the integrity of the story line through" all the great seasons. Murder Leguerta--kill Deb, leave Dex alone without his son--the nonesense had no end. What crap
Comment: While the given answer is correct in that it was a dropped character, one thing that does happen over the season is that Sonya starts noticing (and quietly disapproving) of how little Dexter interacts with Harrison. Even without the character being dropped, I was already expecting her to leave over this, as it seemed to bother her.
Answer: According to the Dexter Wikia, Sonya left the show without any explanation. There was also no explanation as to why Angel Batista's younger sister Jamie took over from Sonya.
The Wikia page for Sonya also adds

Sonya unfortunately fell into the category of characters that disappear between seasons. This is likely due to their contract only requiring their appearance for one season and/or Showtime deciding to drop them afterwards. It's assumed that Showtime felt a younger, more visually attractive woman was needed to replace her for on screen appearances.

According to IMDB, she took up another role Corp & Anam after season 5, so perhaps she was only contracted for 1 season and couldn't be obligated into another season.
Comment: I just like the character and she has more soul in her acting then Jamie. Anyways nice answer.
Answer: I wondered this as well. I would assume it was because Dexter's late night activities caused a problem. Remember she had already quit once and warned him. He probably left her holding the bag again, like he often did to Jamie as well. The plot line likes to emphasize his role as a parent, but he often was an absent father, getting home with barely enough time to tell his child goodnight and often still letting the nanny tuck him in, then leaving again to go kill someone.
Answer: From Entertainment Weekly, showrunner Scott Buck answered it himself:

Dexter's son, Harrison, has a new nanny named Jamie (Aimee Garcia), who is the younger sister of Angel (David Zayas). First of all, what happened to Sonya (Maria Doyle Kennedy), the old nanny?
She was such a fantastic actress but we had kind of wasted her in a way that she wasn't given enough to play, and it felt that by this time it was already a lost opportunity, unfortunately. We thought it was best to move on in a new direction.

So it seems they didn't see any potential for her future arc.


Re-opening my question on ebook managment tools

Question: My question: Ebook management: how to catalog/access files in their original location
I believe my question can be reopened with probably some minor modifications.
Comment: You're missing the point. If you want to ask me if I'm going to close any question on the site that doesn't comply with the rules set forth by our community, then the answer is yes. Mentioning a product name is irrelevant in this context. The problem with your question is explained in the meta post I mentioned in my initial comment.
Comment: You've only changed the title of the question. You're still asking about a specific product. http://meta.superuser.com/questions/5372/how-do-i-ask-a-question-that-may-require-recommending-software
Comment: @OliverSalzburg so what should be done? Are you going to close every single question on the site that mentions a product name?
Comment: Also, the product mention is relevant for the context: I'm seeking to address a specific weakness that is not addressed by it.
Comment: @OliverSalzburg I think you are the one who is missing the point, my question is motivated by a specific but not at all uncommon use case with a type of software, nobody is going to be fooled that this is not the case even if I make ludicrous attempts to hide it. If you are only concerned with semantics, then say so.
Answer: I have edited your question and voted to reopen.  This is a one time deal to show you how to edit the question to better match what we're looking for here.  Please review the meta post that Oliver pointed out.
Also, I don't really appreciate the tone that you've taken up with him.  Oliver is trying his best to be helpful to you and the site.  Treating him with angst and derision is not going to make you very many friends here.  He makes some very good points and I stand behind his actions/words.


Do I need to define 'IOT sensors' when using the term in claims?

Question: Can one expect the patent examiner to know that an 'IOT sensor' is a sensor that communicates to a computer that is networked into a LAN or WWAN?
Answer: No.
No one here can answer whether a future examiner will be familiar with a given term. There are so many examiners which such a range of knowledge and experience.
However, the fact that you are asking the question suggests that the term has not reached the point that an examiner (let alone the person of ordinary skill in the art) would necessarily be aware of it. In such a case, the prudent thing to do is to include a definition in the description. Because what is the downside of doing so?
Comment: This confirms what I thought the answer would be: I was uncertain if I would be insulting the examiner by describing it.  Thanks
Comment: @gatorback An examiner will probably not even read your description unless there is an issue of what a term means, so you shouldn't worry about that. By way of illustration of how elementary your description might be, it's still quite common for computer-implemented inventions to include description about how a computer includes a processor and memory.
Answer: You will describe it, and give examples, in your specification and drawings. Then you can use it the term in your claims if it makes sense.


What establishes the Rendezvous Point when connecting to a Hidden Service

Question: On which side of the circuit does the RP get selected? Is it a random node that the client making the connection to the HS selects or something decided at one of the IPs or by the HS itself?
Comment: I believe client chooses Rendezvous point and sends it to Introducing point.
Comment: Would this leave a higher risk of attack since you're dictating which RP's (that could be owned by the attacker) instead of the HS choosing the RP?
Comment: Connection between HS and RP is again via tor. So even if RP is compromised, it does not affect either.
Comment: Right. I'm just wondering if it falls into the concern about deterministic path selection because my understanding is unlike a normal three node circuit a HS includes the RP as its final node in the circuit. So in the case of a malicious RP, she would see the IP from the HS's previous node and that node has access to the guard node that the HS is using. While the contents of the connection are protected, does it offer enough defense from data correlation attacks of the HS since there's only two nodes (not 3) remaining to protect the identity of the HS.
Answer: According to the Tor documentation it is the client that randomly selects the Rendezvous Point. From step three of the documentation:

Around this time, the client also creates a circuit to another randomly picked relay and asks it to act as rendezvous point by telling it a one-time secret.

The above is the default behavior of Tor clients, but there is an exception. It is also possible for a client to select, non-randomly, a specific relay to use as a rendezvous point. This is described in a Tor Project ticket and rendezvous points to prefer may be specified in your torrc. The relevant field is called Tor2webRendezvousPoints and the Tor2webMode field must be enabled. Google for the Tor manual, I can't post more than two links.
Answer: The paragraph above slide 6 in the Tor documentation link in the 1st answer says the following:

In general, the complete connection between client and hidden service consists of 6 relays: 3 of them were picked by the client with the third being the rendezvous point and the other 3 were picked by the hidden service.

So my understanding is that the rendezvous point is the equivalent of the clients exit node on a circuit that is not going to a HS. The HS has a complete (3 node) Tor circuit of its own, which you can see in the Tor circuit view when you connect to a hidden service because you can't see the IP addresses of the 3 nodes on the HS side. The circuit view shows a circuit that looks something like this:
Tor Browser (client) - Entry Guard - Node - Rendezvous Point - Node - Node - Entry Guard - HS
To the point on correlation, If the rendezvous point is owned by an adversary it should not allow them to correlate any data. To perform a correlation attack they would need to own the two entry guards or you and the HS would need to share the same entry guard, and they would need to own that one guard node. See this link to the Tor design document https://svn.torproject.org/svn/projects/design-paper/tor-design.html most importantly, section 5.1

The RP connects Alice's circuit to Bob's. Note that RP can't recognize Alice, Bob, or the data they transmit.


Falcon9 return to Cape vs barge landings

Question: Is there a way to know in advance when stage 1 will land either on the barge or back at the Cape?
Comment: Generally payload mass is a good indicator.  RTLS takes too much fuel for a large payload.  Starilink missions, for example, max out the payload capacity and always land on a barge.  The Transporter missions, usually are quite light, just hundreds of small payloads and RTLS.
Answer: SpaceX would much prefer to return to the launch site rather than landing on a barge. Compared to returning to the launch site, landing on a barge adds risk, complexity, time, and cost. SpaceX lands its first stage on a barge when return to launch site is not possible. A heavier payload or the need for more delta V are the two key items that preclude RTLS.
Comment: This answers "predict in advance" but to "know in advance" I suppose there may be websites...
Comment: The only time I ever hear of it is when I happen to be watching the news in advance of the launch and the newscaster says they will be returning to the Cape, which happens less and less these days, but their most recent launch did. I don't recall what the payload was!


Can I use the name of a TV serial / movie for my novel

Question: I am planning to write a novel in which the name of one of my character is Agent X but I found out that it has been used as a name of a TV serial.
Answer: Under US laws: If your use of an existing trademark (not to mention a REGISTERED trademark) can be viewed as "likely to create confusion" among consumers, as to the source and affiliation of your works, then it would be (by definition) a trademark infringement.  In theory, you would need permission from each and every owner of a confusingly similar brand, i.e., in related fields.
However, it is not generally a trademark infringement to write ABOUT existing goods or services and reference their trademarks, especially if your writing clearly disclaims any affiliation or sponsorship.
Comment: Someone might also be rescued by the **Scène à faire** doctrine in this particular fact pattern. https://en.wikipedia.org/wiki/Sc%C3%A8nes_%C3%A0_faire


Why does my Italian made gas oven take so long to heat to required temperature. Any tips please

Question: I have a Glem Gas Oven that can take over 30 mins to heat to desired temperature.  I was advised to place a pizza stone on the bottom of the oven but it still takes longer than 30 mins to reached desired heat.  Any tips please.
Comment: You do have the correct nozzle in, do you?
Comment: What's your gas source? I've seen an overloaded gas pipe from a tank lead to slow preheating if other appliances are using gas at the same time
Comment: Natural gas.  No other gas appliances other than cooktop and heater which is not on all the time.
Answer: I don't see anything unusual here. Ovens are a big mass of steel and other materials that has to spend some time heating before it is at working temperature. Many ovens turn off as preheated somewhat earlier - see also this question where the answers speak of 15-20 minutes of preheating on average - but this doesn't have to be the correct answer for your case. Maybe you are looking for a higher temperature, maybe your oven is larger, or maybe your oven only has one heater on the bottom as opposed to the two heaters common in electric ovens. Also, I suspect that many ovens, even though they turn their light off as "preheated" after 15 minutes, are not truly as well heated as they should be - if I bake several things back-to-back, the later ones bake quicker and more evenly.
A pizza stone will actually make the preheating slower, because you are adding cold mass that needs to be heated. So don't expect any change there, unless you decide that, by having a pizza stone, you can afford to place the food in the oven before it has reached its desired temperature, hoping that the heating help from the stone will compensate for the too-low-starting temperature.
If this is the case and the oven is working as intended, there is not really anything you can do about it. Baking is a slow method anyway, so you have to just take it as it is. You may consider adding a large-sized toaster oven (one of those with 30-40 cm width and depth of the cooking space) and bake quicker things in it. It will be especially useful if your main oven doesn't have a top heater.
If you think that the oven is designed to preheat quicker, then you have to call customer support or an independent repair service to see where the defect comes from.
Comment: thanks for your input.  Most appreciated.  Will try without pizza stone and see how it goes.


How to fetch record id using Salesforce instance URL address

Question: I have VF page and placed that in home side bar component page and I am capturing the Salesforce instance URL from visual force using custom controller.
public String getReferer()
{
    BrowserURL = ApexPages.currentPage().getHeaders().get('referer');
    return browserURL;
}

Now I want to fetch recorded id using Salesforce instance URL in VF page.
How can I get record id using that URL. Eg:
I am getting Salesforce browser URL like: https://ap1.salesforce.com/0019000000GJMHG
using this URL How can I get Salesforce record id through controller and display the record id in VF page. Like : Record Id: 0019000000GJMHG Can anyone please help me to overcome this issue?
Comment: One thing to be aware of is that because referer information can violate privacy, some web browsers allow the user to disable the sending of referer information. Don't rely on this referral information as it's possible that it will not be present. If it is critical to know the ID from the previous page, pass it along as a URL parameter in the link.
Answer: I've done this in javascript in the past and it boiled down to two regular expressions:
for the / URL format:
/\.com\/\w{15}|\.com\/\w{18}/

and for the ?id= format:
/id\=\w{15}|id\=\w{18}/

It's not foolproof - any VF page can use custom parameter names, but it covers all standard UI pages I'm aware of any any visualforce that uses a StandardController.
Answer: I guess you can use the string methods now to pull the ID.
BrowserURL=BrowserURL.right(15);//Pull from right the 15 digit Id

If your org is not update to winter 13 then you can use  String.Split('/') and get the last array element value .
Comment: This won't work if there are any get params in the URL, specifically the retURL param will be present on a large number of pages.
Answer: Not sure if this is completely foolproof, but seems to be working for me
Example:
BrowserURL = ApexPages.currentPage().getHeaders().get('referer').Split('/')[3].left(15);


Pool alarm with wireless remote alarm, how to integrate with it?

Question: I have this pool alarm http://www.diycontrols.com/p-6711-sensor-espio-inground-pool-alarm-safety-item.aspx. I would like to log whenever the alarm goes off so I know if it is tripping while I am gone very often. How can I find out when a signal is sent? I don't want to hack into the remote alarm, but actually detect the radio signal.
Answer: Looking at the manual, this is FCC certified. That means you can find out a lot about it.
I went to here and searched by the parent company's name, MG International, bringing up 4 applications. One of these is the Sensor Espio.
From there, I can see it works on 433.92 MHz - this is probably the most common band for wireless devices. The schematic is available - it uses a TI CC1100. The operational description says it uses OOK with a 16 bit security word and 8 bit command word.
Most of these 433MHz devices use fairly simple Manchester encoding, sometimes using infra-red remote protocols over RF. I've not used a CC1100 before, but have used a CC1110, which is fundamentally the same. They have a lot of fancy features for FSK and MSK, but are quite basic and hard work for ASK/OOK. I think this means that the protocol is essentially free choice, but most of these will be a long preamble of 1010101010 or similar, followed by the security/ID and then command word repeated several times.
You can use any of the simple 433MHz receivers to pick these raw signals up, but then you will need to use a microcontroller or similar to wait for the preamble and listen to the words. The website JeeLabs has a large number of tools to help you connect a 433Mhz receiver to an Arduino and decode it.
By logging - do you mean simply recording? Any microcontroller can do this. Or do you mean alerting you via SMS or email?
Comment: Wow, this is great info. For now I am going to just log (most likely to a pc), but in the future I may write an Android app and setup a server so I can see it real time.
Comment: As I am US based I was thinking of picking up this http://www.sparkfun.com/products/11018 it looks like it should work.
Comment: I'd avoid the RFM22 modules. They have a microcontroller inside them and it is hard to force them away from using their own internal state machine to deal with reception. They are great modules - I have about 20 in my house reporting various things to a central node.
Comment: I used things like these http://www.seeedstudio.com/depot/433mhz-rf-link-kit-p-127.html?cPath=139_140 which just have a digital out and deal with the automatic gain control themselves. You just need to listen out for the preamble to work out when it is gained up and showing you noise or receiving an actual signal.
Answer: You probably won't have much luck just detecting the radio signal. There is noise on every frequency, so your alarm listener would probably constantly detect a signal. What you would need to do is listen for a valid wireless message. But you will need to do some major reverse-engineering to figure out what constitutes as a valid message. Much better to hack into the remote which is already programmed to receive an alarm message. I would probably just add a mosfet to one of the alarm outputs which activates your own circuit to perform logging.
Comment: This is definitely the problem and unfortuanlty you will need to hack into to the receiving  device and add something to it. Unless you can find the exact frequency and protocol.. its a needle in a haystack
Answer: You can just attach a latching device so when it gets switched on, it stays on. Search for SCR (thrysistor). You can attach one to an LED, and if the LED is on, then you will know. Attach this to the remote.
To log, I know of a clever instrument. You can have a photoresistor attached to a 555 timer circuit. Attach output to tape recorder. As you play back the recorded tape, if there are any frequency changes, you know that it has gone off. Point the photoresistor at the indicator lights.
Or you can just place a tape recorder next to the alarm. Attach mike. Point mike at speaker of the alarm!
Answer: If you can hear the alarm, you dont need the RF signal, just filter the audio tone with a good BPF and a cheap mic and an event monitor perhaps on USB with suitable software or use an auto-dialer to your desk at work.
BPF of my choice is a high Q Sallen & Keys with adjustable F and adjustable Q to tune to Pool alarm. Or higher Q with State Vbl BPF adjusting Q with Ra.
Choose Q>100
Comment: Great idea thinking "outside the box". But I am interested in learning about RF and this is an opportunity to do so.


Help with xmodmap example from archwiki

Question: This article: https://wiki.archlinux.org/title/xmodmap#Reassigning_modifiers_to_keys_on_your_keyboard
Has an example:
clear lock
clear control
add control = Caps_Lock Control_L Control_R
keycode 66 = Control_L Caps_Lock NoSymbol NoSymbol

That maps caps_lock physical to the function control and  physical shift + caps_lock to the function caps_lock.  My problem is that I don't know how this example works.
My intuitive (but incorrect) understanding of how these lines should work is:
you clear the lock/control modifiers. I naively think that lock means caps lock but this is probably incorrect.
Then the add control = Caps_Lock Control_L Control_R means 'the keysyms Caps_Lock Control_L and Control_R will trigger the control modifier.
Then the last line: keycode 66 = Control_L Caps_Lock NoSymbol NoSymbol should mean (in my head but not in reality) map the physical key with keycode 66 (the physical caps lock key) so that alone it gives keysym Control_L (triggering the control modifier per the previous line), and shift+keycode 66 should (and here's where I'm confused) also just trigger the Caps_Lock keycode,  and therefore the control modifier.
I've experimented with various modifications to this with further unexpected results.
I find the documentation for xmodmap (both in the manpage and archwiki) to be terse and unhelpful.
So I am wondering if someone could explain what's going on with this code. Also the functions of the control and lock modifiers because I've realized that the lock modifier is not just caps lock.
I know that XKB is the recommended config tool now, and that doing complicated things with xmodmap is discouraged so maybe this is just one step too far.
Answer: Read this Linux: xmodmap Tutorial, and maybe this topic and you will understand it better.

Help with xmodmap example from archwiki


How to design a complex multi approval expense db schema in MySQL

Question: I'm very beginner in database design and had the following problem to solve.
DB schema design for an expense approval system with these cases

approval system, every company has 1 or many teams where rules can be different
let's say for marketing team invoice needs to be approved by HR & CEO
while for engineering team, invoice needs to be approved sequentially by Engineering Manager to HR and last to CTO
there are also parameters that can define rule like amount of invoice
let's say for invoice > 1000 USD, will need approval from CEO while invoice < 1000 USD doesn't need it,
And for invoice category of office_supplies, need to be approved by GA
User should be able to query and get all the invoices required to be approved

The schema must be dynamic and adaptable to future changes in business logic
I have designed a simple schema as a starting point, please help in adding the approval rules.
I would also appreciate any links or resources which could help me get started for problems like this.

Thanks.
Comment: All of these requirements are better implemented at the application level. The only harder consideration is the data structure for to account fro multilevel approvals and how that is modeled. Look as the SQL queries generated for your current structure and it might become more obvious how to model this different (if there is a need at all).
Answer: Check out database triggers for defining dynamic rules:
https://www.geeksforgeeks.org/sql-triggers/


Multiple comparisons tests

Question: Multiple comparisons tests, such as Dunnett's, Tukey's HSD, or Bonferroni, may be performed without a significant, "preliminary" one-way ANOVA (many of these tests were created to deal with multiplicity in general rather than be a "next step" to ANOVA). Anyways, if a researcher is using a factorial design that includes two main effects and an interaction (e.g., the associated analysis may be a two-way split-plot ANOVA), then does the interaction (or one or both of the main effects) need to be statistically significant before (s)he can perform multiple comparisons tests or simple main effects tests?
Answer: You should dig further into the results only when there are significant interaction or main effects. If interaction effects exist, the main effects are not that interesting.

Multiple comparisons tests


Was Lemuria mentioned in ancient texts?

Question: Lemuria is a mythological place said to exist in Indian ocean, below current indian sub-continent.Was it ever mentioned in texts.
Answer: Lemuria is an imaginary story.
Yes. There is no concept of Kumari Kandam aka Lemuria before 1600s. During 17th century, it was placed between Australia and North America. Later it was renamed as MU and another continent was placed below the Indian ocean adjoining with Madagascar. Due to similarities between lands in Madagascar, Australia  and southern India, it is believed that in ancient times, there may be a continent joining India and Africa(Madagascar).It was named as Lemuria. But today we discovered continental drift theory. As per this theory, India, Australia and Africa including Madagascar were joined many millions years ago. As the continents of Africa and India were joined, that's the reason why we have similarities between Africa and India. So, we don't need any continents in-between.

Coming to your question, let's see whether Lemuria is mentioned in texts before 1600s:
Silapadikaram
It says.

kumarikodum kodunkadal kolla.....

The mighty sea at the end of kumari(kanyakumari,not Kumari Kandam) submerged. Here the author speaks about sea around kumari submerging the puhar(keveri pattinam) port. Silappadikaram'also describes Kadal Vadimpalampa Nindra Pandyan said to have thrown his spear towards the sea. The sea retaliated by swallowing a large area including Pahruli river and Panmalai Adukkam.
Manimekalai
It
Records the same incident of the puhar being engulfed by sea. Silapathikaram and manimekalai both not being eyewitness accounts and known for gross exageration of facts clearly talk sea engulfing the city of puhar.
Kalittogai
Sangam literary work, `Kalithogai' calls it Kadal vowal. The poem says that when tidal waves swept away his land, the Pandyan monarch did not despair, but forged ahead into the territories of Cheras and Chozhas and brought the invaded country under his sway, thus making good the loss of territory due to the sea-swell.
Mahavamsa
It records say sea taking the land (Tsumani, in which a smaller portion of land in Sri Lanka, not Kumari Kandam) in 4th century BC.
If you look at the various arguments, Lemuria is just another attempt to increase the antiquity of Tamil to pre-historic times.

Was Lemuria mentioned in ancient texts?


phase amplitude transform as a solution to reverberation

Question: I am trying to use generalized cross correlation with phase transform (GCC_PHAT) on some audio processing indoor, with the existence of low noise. I ve read here that by canceling the magnitude factor, which what pretty much PHAT does, the result of the correlation will be resistant to reverberation and low noise, but i cannot seem to understand why.
I want to know what is the explanation behind that, what is the relationship between reverberation and magnitude ?
Answer: First of all, what do you mean by "cancelling the magnitude factor"? According to the paper by Knapp and Carter (1976), the phase transform (PHAT) was developed as an ad hoc technique. What the transform does is place equal emphasis on each frequency (pre-whitening), but according to the paper by Braindstein and Silverman (1997), the PHAT-weight is suboptimal under ideal conditions.
I am also not sure what you mean by "the relationship between reverberation and magnitude". Reverberation is the effect of reflection subject to room geometry/materials. Basically this means that lots of delayed and attenuated copies of the signal is added to the signal itself.
Comment: http://www.xavieranguera.com/phdthesis/node92.html, |X(f).*Y(f) | isn't that the expression of magnitude?  i wanted to know what makes it resistant against reverberation? what is the trick in dividing by that expression? i cannot seem to find a clear explanation in their paper.


Why do my particles grow outside the density vertex group?

Question: I made a particle hair system and a vertex group for control its density, but it doesn't seem to have any influence.
as you can see in the picture, hairs grow everywhere. I checked if I weight paint the same texture as I use and I don't know, what other reason this could have. I also noticed, that if i add interpolated (doesn't change anything if it is simple children) children, everything works all right, but not in particle edit mode. I tried rendering it and the rendered image doesn't have any hair outside the density group.
Comment: More information Please. Please show all vertex groups.  In edit mode. Select None. Then select all the member of the vertex group that appears in the density of the particles system.  If you have multiple vertex groups make sure you are editing the correct vertex group.
Comment: Try selecting the vertices of the head in edit mode and removing them from the vertex group.
Comment: PGmath - I tried that. It didn't help.
Comment: In the second image with that selection of the vertex group .... when you move the selection far .... is the selection what you think it should be?
Comment: what do you mean - move far?
Answer:
One vertex group.

The other vertex group.
If you have multiple vertex group make sure you are viewing and editing the correct one.
Also make sure your blue color is exactly blue.  Paint it again to be sure.  Zoom in from different rotation angles for nooks and cranies.  Rotate the model so you are always facing the mesh face directly while painting.  Delete the vertex group, create it again, and use the new name in the Particle System.
Comment: I checked, if I am editing the correct one (this was in the question). I am.


Can libsodium's secret box be configured to use a cipher other than Salsa20?

Question:
I understand this question may seem better-suited for Crypto.SE or Security.SE; I'm asking it here because I'm specifically asking for help with the API rather than asking for technical or historic background.

I'm currently looking at integrating libsodium into one of my projects via PyNaCl. Having scanned the docs for both these projects (admittedly not super thoroughly), it doesn't look to me like there's a way to use an a cipher other than Salsa20, the default.
This doesn't pose an immediate problem for me since Salsa20 seems to be both reasonably secure as well as being performant, but in the future, I may want to use a different algorithm. Is this kind of toggle provided by either library (and ideally at the PyNaCl level)?
Answer: The box operation just performs a scalar multiplication in order to get the shared secret, and then performs authenticated encryption using that secret.
The former is done with the scalarmult API, that you can call manually to get the same key as the one box would compute.
The later is the secretstream API, that you can also call manually using the shared key from the previous step.
Libsodium has a slightly better key exchange API: kx (crypto_kx) that you can use for the first step.
And for the symmetric operation, it also provides alternatives to XSalsa20 (-Poly1305), in particular in the AEAD APIs: XChaCha20 (-Poly1305), AES-256 (-GCM) and AEGIS-256.
But, really, there is nothing wrong with XSalsa20. It has a comfortable security margin, and its large nonce size is very convenient.


Shirk in the mind repeating

Question: Assalamu Alaikum Warahmatullahi Wabarakatuhu,
Lately I have been having thoughts of shirk pop into my head. The other day I was daydreaming and imagining myself talking to someone and In my mind I swore by something other than Allah which is shirk, except it wasn't intentional I was just imagining me talking to someone and then all of a sudden I swore by something other than Allah. It just popped into my head as soon as I had the thought I started saying "Astaghfirullah". Nothing was intentional and it keeps happening to me and replaying in my head. Have I committed shirk?
Answer: Alsalam alikum brother/syster the prophet [pbuh] once got asked if we sre judged by our thoughts and he said

"Allah [swt] has forgiven my ummah for there thoughts as long as thry
don't say or do by that"

so if you get any bad thoughts it is okey the only importent thing is to take refuge by Allah from the Devil and to not react on it or do anything about it.

Shirk in the mind repeating


What is the constant $G$ in Newton's law of gravitation?

Question: I know very little about physics. So, please forigve me if I ask anything wrong. I just read an article about gravitation. Where I saw an equation $$F = \frac {Gm_1m_2}{r²}$$ where $F$ is gravitational force, $m_1$ and $m_2$ are masses of two bodies, $r$ is the linear distance between the bodies and $G$ is gravitational constant. What is this gravitational constant? Can someone will explain it to me? A good explanation will be really appreciated.
Comment: Not sure about this question. It's interesting to think about and explain what $G$ is, but the wiki page is quite good already https://en.wikipedia.org/wiki/Gravitational_constant
Comment: My only issue with the wiki page is that it calls it all sorts of things (Cavendish constatant etc) apart from what I ever hear anyone actually calling it: big G or Newton's constant.
Answer: $G$ is a value inserted to make the two sides of the equation equal. If everything else on the right hand side has a value of $1$ (for example, you have two one kilogram masses separated by a distance of one metre) then $G$ is the numerical value of the gravitational force between them. In SI units the value of $G$ is about $6.674 \times 10^{-11}$.
As far as we know, the value of $G$ cannot be found from theory - it has to be measured in experiments such as this one. Also, as far as we know, the value of $G$ is constant - it is the same everywhere in the observable universe, and does not vary with time.
For more details see this Wikipedia article.


In Android how to concatenate base64 encoded strings?

Question: Please help me to solve this:
I have two strings for email-id and password like
String name = "firstname.lastname@example.com";
String pass = "abc";

I encode these two into Base64 string like
String encoded_name = new String(Base64.encode(name.getBytes(), 0));
String encoded_pass = new String(Base64.encode(pass.getBytes(), 0));

and I need to concatenate these two encoded strings with space like
String merge = encoded_name + " " + encoded_pass;

I checked this string in console by
System.out.print("Concatenate string= " + merge);

but in console I am getting result in two lines like this
11-18 00:25:29.898: INFO/System.out(1244): Merge= eHl6QGdtYWlsLmNvbQ==
11-18 00:25:29.908: INFO/System.out(1244):  YWJj

Why is this happing the result is unexpected for me why it is not printing in a single line. please help me to solve this.
Thanks
Comment: I have never used System.out to show information in android, can you try with the Log class? Log.e("BASE64", merge);
Comment: Check if your Base64 string ends with a "newline", or remove it with *String.trim()*.
Answer: You should use the NO_WRAP flag as described in the Docs, the Base64 class will not add additional newlines.

NO_WRAP: Encoder flag bit to omit all line terminators (i.e., the output will be on one long line).

So change your lines to the following:
String encoded_name = new String(Base64.encode(name.getBytes(), Base64.NO_WRAP));
String encoded_pass = new String(Base64.encode(pass.getBytes(), Base64.NO_WRAP));

This will output the following:
11-17 19:16:51.283: INFO/System.out(354): Concatenate string= eHl6QGdtYWlsLmNvbQ== YWJj

Answer: Please have a look on Android Api reference Document. It will solve all other queries regarding Base64 encoding/decoding in android.
one more efficient way to solve your problem:
String encoded_name = Base64.encodeToString(name.getBytes("utf-8"), Base64.NO_WRAP);
String encoded_pass = Base64.encodeToString(pass.getBytes("utf-8"), Base64.NO_WRAP);

out put:-
11-17 10:55:27.492: V/BASE-64-.encodeToString(525): eHl6QGdtYWlsLmNvbQ== YWJj

Answer: Look at this doc, the mime section states that
MIME does not specify a fixed length for Base64-encoded lines, but it does specify a maximum  line length of 76 characters. Additionally it specifies that any extra-alphabetic characters must be ignored by a compliant decoder, although most implementations use a CR/LF newline pair to delimit encoded lines.
You should only consider removing  the last char of your first base 64 string, it seems to be a \n (a more generic method would be to test wether it is or not.)
Regards,
 Stéphane


Why do airlines over-estimate/over-calculate flight times?

Question: A specific example I'm referring to is Cathay Pacific's CX138 flight between Sydney and Hong Kong. This flight is scheduled to be 9 hours & 40 minutes long (departing SYD at 22:20 local time and arriving HKG at 05:00 local time) but in reality from Flightradar24 data, as well as having been on the flight, it seems that this flight consistently arrives around 03:45 to 04:00 average, which is a very early arrival. So why is the scheduled flight time so over-stated ? (Ironically, other CX flights between SYD & HKG at other times of the day have shorter scheduled flight times)
Comment: Unless someone from an airline answers directly for *their* company, in spite of plausible reasons, answers might be opinion-based.
Answer: Mainly, to improve their image. Though I'm not sure about this specific flight (or airline, for that matter), it appears that over estimating flight time is usual.
For airlines it is better to overestimate the flight times and then claim that they are punctual, rather than correctly say the required time and then be late due to some unforeseen reasons. For example, if an airline says that a flight takes 80 minutes (while in reality, 60 minutes suffices) and then completes it in 70 minutes, the perception will be that the flight is early. After all, nobody is going to check the exact time required for flight.
In general, the airlines would add some extra time to cater for things like tarmac congestion, holding time, connecting flight etc. However, it appears that the airlines are increasingly padding their 'block times' (which includes estimated flight time, taxi time at both ends, and time for short delays) in order to appear punctual.
This report by USAToday points out that (in US) more flights were arriving early than late (in 2012) and it appears that the trend remains the same. The report points out:

The average flight from Boston's Logan airport to New York's LaGuardia took one hour in 1995. In 2012, it took 75 minutes.
Yet the Logan-to-LaGuardia early-arrival rate soared to 38% last year from just 2% in 1995 as Delta and US Airways added nearly 20 minutes to the schedule.

This makes the passengers think that the flights are on time, though they are actually late (when compared to earlier timing). For example, U.S. Department of Transportation considers a flight as 'on time' if it arrives at its destination within 15 minutes of the scheduled arrival time and without being diverted or canceled and can penalize chronically delayed flights i.e. if they are more than 30 minutes late 50% of the time.
There are other issues here- it takes time to buildup data in specific routes and airlines are cautious in the meantime, airports are getting more and more congested making the total flight time to increase etc., but even taking these into account, it is better for airlines to overestimate than underestimate.
Comment: The ability of the US DoT to penalise chronically delayed flights is a big part of it: add 30 minutes to your expected flight time and your company will be fined much less often! Unlike trains or buses, most people don't compare flights based on flight time and just accept "that's how long it takes" so there's little reason to try to under-estimate the flight time. Similarly in the EU delayed flights can cause compensation claims. Perhaps also worth mentioning that if you hit a headwind, you can easily add a lot of time to a journey: most flight times are "worst case"
Comment: "This makes the passengers think that the flights are on time, though they are actually late." I'm sorry but that's complete nonsense. If the flight arrives before its scheduled time, it is in no sense late.
Comment: @JonStory - and if you hit a tail wind, you can throttle back and save fuel.
Comment: @DanPichelman not really, jet stream or no your indicated airspeed is the same, and that is all that matters to the wings.  You might have a bit of room to "throttle back" but you'll also need to ask ATC and every plane behind you will have to slow down as well, so in practice it just doesn't happen.  You fly your dispatched mach number and watch the groundspeed soar.
Comment: @casey, unless you are flying Cost Index, in which case you will slow down to take economical advantage of the tailwind.
Answer: Other than appearing punctual, it will help in preventing connecting flights being missed and to catch up after delays


Is Windows 10 32 bit good for iMac 4,1 running Bootcamp?

Question: I have an iMac 4,1, 2Gb RAM and installed Bootcamp.
Is Windows 10 Home Premium 32 bit good for that machine? Or is it too heavy, better install Windows 7 Home Basic 32 bit?
Answer: The latest supported Windows version for that machine is Windows 7, 32-bit.
There will be no drivers available for Windows 10.
Ref: Everymac
Comment: What do you think happens when you install windows 7 and then upgrade to Windows 10?
Comment: Someone told me Windows 10 finds old drivers if the machine does not accept new ones.
Comment: @DavidAnderson - The same as if you tried the same on any 12-year-old PC with an X1600 GPU & all that goes with it... ancient drivers, new OS, no support.
Answer: Your Mac meets the minimum requirements to run Windows 7 and 10. Generally, Windows 7 (SP1) requires a product key to download and install. Windows 10 does not. In either case, if you wish to keep Windows after a trial period, you will need to purchase a license. OS X does not have to be installed on the Mac before installing or using Windows, provided you have the Snow Leopard DVD. You could also install both versions of Windows as a dual boot. This way you could boot each and compare speed and features. With dual boot, you first install Windows 7 in one partition, then Windows 10 in a different partition. The Windows 10 installer will automatically setup the dual boot software.
Since Windows 10 did not exist when Snow Leopard was released, you will probably need to run the Boot Camp Support Software installer in Windows 7 compatibility mode. If this still does not work, then consider first installing Windows 7, then the Boot Camp Support Software, and finally upgrading to Windows 10.
When running a newer version of Windows that is not officially supported by Apple, you will often find the Device Manager will show errors. Usually, these errors are generated by redundant hardware that is not used anyway. One solution is to provide a null driver which effectively just removes the errors from being displayed in the Device Manager. If your Mac appears to work properly, then the simplest solution is just to ignore the displayed errors. This problem is not unique to Macs, the same is true for all other of machines capable of running Windows.


Double-hitch longboard

Question: My friend just got a new longboard, and he says it's "double hitched." When I Google double hitched longboard, it comes up with nothing familiar. His longboard turns extremely well, and I'm wondering what the actual name is. BTW His trucks are longer on the inside.
Answer: Double hitch trucks are used in competitive longboarding (yes there is such a thing). They give the board a larger turn range, giving the rider the ability to make hairpin turns at higher speeds than your standard Thunder trucks. I only know them by that name but I imagine every company has their own name for them. Those are high quality trucks.

Double-hitch longboard


Multicast summarization

Question: I was wondering, does it make any sense to summarize(supernet) multicast IPv4 addresses ? Can anyone please explain why yes, or no ?
Comment: The term supernet doesn't make much sense with multicast since each group is an individual address (`/32`). You can summarize multiple groups in routers where you use multicast routing (very different than unicast routing). For example, there are commands in Cisco multicast where you can either use individual multicast groups, or you can use a range by summarizing.
Comment: But if I want to send something from a network three hops away from that multicast group(and where that group is there are more multicast groups also), does it make sense then ? For example, on the first router, i put the summarized address and next hop to the second router, and so on.. , and the last router then decides which group will receive the frame .Thank you for your comment.
@RonMaupin
Comment: Multicast routing is very different than unicast routing. Multicast groups are individual addresses, not networks. Multicast routing is difficult because it must strive to not send traffic where is has not been requested. It starts with IGMP between a host wanting traffic and a multicast router, and there is PIM between multicast routers. The subject is really too broad to deal with here.
Answer: I think it always makes sense to summarize or supernet your IP addresses.
Supernetting is also known as CIDR (classless interdomain routing) as defined by RFCs 1517, 1518, 1519, and 1520. In IPv4, CIDR is one way of attempting to manage the shortage of TCP/IP addresses until IPv6 takes over.
ISPs frequently use supernetting to allocate IP addresses most effectively. There may be scenarios where you have many LANS, WLANs, or VLANs that might be optimally suited for supernetting to best administer your network needs. Keep in mind that supernetting introduces complexity to network administration that needs thorough planning, testing, documentation, and administrator competence.
Most new routing equipment and current operating systems support CIDR in their implementation of the TCP/IP protocol. However, before a supernetting implementation, it is critical to ensure that all components of your network are supernetting-aware. This includes operating systems, network services, routers, routing protocols (RIP2, for example does not support CIDR), and any network-based services used on your network.
Comment: Thank you for Your answer. I was confused, because i found here
https://www.cisco.com/c/dam/en/us/support/docs/ip/ip-multicast/ipmlt_wp.pdf
, and I quote "Because any multicast source can send to any group address and any multicast client can receive any group without regard
to geography, aggregation and summarization of multicast group addresses are meaningless" , so can you please comment that quote ?
Thank you very much
Comment: Well the guide also states: "• Internal policies on the control and deployment of network applications—Depending on the network topology,
certain constrains and protection mechanisms may need to be put in place to protect network resources. A well summarized
address range can help to simplify this process." - This would be a good idea if your locations span wide and you need to control which sites are allowed to connect to the streams.

Multicast summarization


tag and favicon aren't correctly showed by Google Search

Question: I'll go straight to the point.
For a few days I've been working on the SEO on my website and I noticed that the favicon still isn't showed by Google Search and that the <title> tag is showed wrong! See the screenshot.
About the favicon, I have it in my root folder and the tests on realfavicongenerator.net and on the Google favicon checker don't return any error.
About the title, the problem is that it's shown like "Blogsonic: Home", while it should be "Home | Blogsonic". The weird thing, as you can see on the screenshot, is that the title on the About page works fine!
Here's is how my header file looks:
<!DOCTYPE html>

    <title><?= $title; ?> | Blogsonic</title>
    <?php
        if (isset($meta_description)) {
    ?>
        <meta name="description" content="<?= $meta_description; ?>">
    <?php
        }
    ?>
    <link rel="alternate" hreflang="it" href="<?= base_url('it'); ?>">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta property="og:image" content="<?= base_url('public/img/blogsonic-social-preview.png'); ?>">
    <meta property="og:image:type" content="image/png">
    <meta property="og:image:width" content="1280">
    <meta property="og:image:height" content="640">
    <link rel="apple-touch-icon" sizes="180x180" href="<?= base_url('public/icon/apple-touch-icon.png'); ?>">
    <link rel="icon" type="image/png" sizes="32x32" href="<?= base_url('public/icon/favicon-32x32.png'); ?>">
    <link rel="icon" type="image/png" sizes="16x16" href="<?= base_url('public/icon/favicon-16x16.png'); ?>">
    <link rel="manifest" href="<?= base_url('public/icon/site.webmanifest'); ?>">

    <link rel="shortcut icon" href="<?= base_url('favicon.ico'); ?>">
    <meta name="msapplication-TileColor" content="#426e9c">
    <meta name="msapplication-config" content="<?= base_url('public/icon/browserconfig.xml'); ?>">
    <meta name="theme-color" content="#ffffff">

    <link rel="stylesheet" href="<?= base_url('public/css/bootstrap.min.css'); ?>"/>
    <link rel="stylesheet" href="<?= base_url('public/font-awesome-4.7.0/css/font-awesome.min.css'); ?>"/>

Note: If you think that embedding PHP in HTML is bad, you should see the rest of my code... Jokes aside, I just don't care. This is literally my first web project ever and now I'm more focused on using it as a "playground" to test things.

I've also used the Google Search Console to update the pages and everything looks fine. As you can see from this screenshot the last updated date is October 2nd, 03:22 AM.
If you need me to show you other parts of my code, you can ask me here and I'll be very happy to answer you, or you can see the GitHub repository.
Can anyone help me? Thanks in advance!

Note: English is not my mother tongue. Forgive me if I've made some mistakes.
Answer: The size of your favicon must be a multiple of 48 pixels square, for example:
48 x 48 px
96 x 96 px
144 x 144 px
Don't use 16x16 size, Google will resize it automatically.
Define a favicon to show in search results
<link rel="icon" type="image/png" sizes="48x48" href="public/icon/favicon-48x48.png">

Comment: It already is 48 x 48 pixels: https://www.blogsonic.org/favicon.ico
Comment: Try doing the PNG version, I don't know how long it takes Google to update the result. If it doesn't work, the icon may have been misinterpreted by Google robots.


How to trigger the auto-completion in a comment when referring to a non-latin user name?

Question: I want to make a comment for this answer but because one user has a Chinese character as its user name, I failed to refer it in the comment. Shortly speaking, how to trigger the auto-completion (aka IntelliSense in Visual Studio) for a non-latin user name?
Answer: On a qwerty keyboard, you need to copy at least the first character from the name and paste it after <code>@</code> in order to initiate the auto-completion:

If selection from the available comments is difficult (due to hyperlinks), click on the user name and select from the user profile.
Comment: @ガベージコレクタ -- of course, one could say that when trying to comment to you!  (but it's a terrific question, and i'm sure i'll get a lot of use from the answer.)  and i've discovered that if one starts copying from the right-hand side rather than the starf of the name, it's more likely to work; also true for urls.
Comment: @ガベージコレクタ: What the ... this is you, garbage collector/higgs bosom/moderator/underground? Well, [makes sense I guess](http://translate.google.com/#auto/en/%E3%82%AC%E3%83%99%E3%83%BC%E3%82%B8%E3%82%B3%E3%83%AC%E3%82%AF%E3%82%BF) ... :).
Btw, you aren't by chance in any way related to our now unfortunately inactive member [xport](http://tex.stackexchange.com/users/2099/xport)?
Comment: It is a bit cumbersome. :-)
Comment: @barbarabeeton: i see. thank you.
Comment: @doncherry: Only god knows. :-)
Comment: @ガベージコレクタ I knew there was something going on ... :)
Comment: @doncherry: I changed to the current name because in the past we could not use non-latin characters for display name. I  tried it many times long long time ago. The chinese (in question) above inspired me to change to the current name and I believed that this is a new feature from SE.