Difference between PPI networks and Gene Co-expression networks

Question: What exactly is the difference between protein-protein interaction (PPI) networks and gene co-expression networks? Based on my rudimentary understanding, PPIs are constructed from gene co-expression networks, and so represent processed data. But could someone elaborate more on the differences?
Answer:
Based on my rudimentary understanding, PPIs are constructed from gene co-expression networks

Not really, no. PPI stands for protein-protein interaction. In PPI networks, each node is a protein and each edge (line) connecting it to another node represents an interaction. A very common example is that an edge represents a physical interaction between these two proteins. This means that there have been experiments to indicate that these two proteins come into contact in the cell and interact.
For example, they might form part of a protein complex, so their interaction was seen using chromatin immunoprecipitation, where the two proteins were captured together. Or, they may have been seen together using FRET, a technique that lets you detect when two molecules are in very close proximity.
Alternatively, some interactions can be theoretical, where in silico modelling has suggested that these two proteins can interact, even though we don't have any direct evidence that they do so.
Finally, yes, it is also possible to make a PPI network based on gene co-expression data, under the assumption that if two genes are co-expressed, then their protein products will be present in the same tissue. However, that doesn't mean they interact in any way, so it isn't really a very common way of building PPI networks, as far as I know.
In co-expression networks, on the other hand, each node is a gene and not its protein product. And here, the edges indicate the coexpression. Often the level of correlation between the two genes' expression data.
The most important difference between these two kinds of network, apart from the obvious mentioned above, is that they are used in different ways. A gene coexpression network lets you identify genes that are regulated in similar ways. It is a tool you can use to investigate the regulatory network of the cell, to see what genes are "turned on" or "off" together.
The PPI network, on the other hand, is a way of understanding the result of this gene co-regulation. You are not looking at how the gene network is regulated any more, but how the products of the genes interact with one another. So it is a very different focus.
You can maybe think of this in terms of school children and their parents. You could make a network where each node represents a pair of parents, and then draw lines between them if their children were born in the same year. That would give you a general overview of when this group of people procreated. However, that two children were born on the same day doesn't necessarily imply that the children themselves will ever come into contact. This could be the equivalent of the gene co-expression network.
Then, make another network where each node is a child and draw a line between any children who know each other. This would be the equivalent of the PPI network. You would likely find some correlations between the two, with children who know each other being more likely to have been born at around the same time, but the two networks give you very different information.
Answer: Co-expression networks are based on gene expression data. Genes are compared using their expression profiles over multiple samples. A common distance measurement is the Pearson Correlation Coefficient, assuming that co-expressed genes (genes expressed simultaneously in similar conditions) will have a high correlation coefficient.
In its simple form, a co-expression network is done like this. An expression matrix containing n genes x p samples is used in input (from microarrays or RNA-seq) to calculate a distance matrix of size n x n. Then the distance matrix is thresholded to keep only the most significant relationship (eg correlation >0.8). Gene pairs are connected if their correlation coefficient is above this threshold. Then all connections are visualized in a network, which can then be subjected to community detection algorithms to find more densely connected set of genes.
PPI are usually built on in vitro assays such as Yeast-2-Hybrid. But connections can also be inferred from literature data and expression data. You may have a look at the StringDB for example to see which kind of data can be used to connect proteins.
Comment: It is also possible to infer regulatory networks from gene expression data using specific data (eg mutants in transcription factors and controls) and specific metrics (eg bayesian inference). Infering a regulatory network is generally more challenging.


Are old versions of D&D compatible with new ones?

Question: Some 30 years ago I used to play Dungeons and Dragons: red 'Basic', blue 'Expert', black 'Master' edition box sets, etc. I still have them and was recently playing with my son, who loved them. I want to get him his own sets, and thought the D&D essentials Monster Vault looked good. My question is, would this set be compatible with my old sets in any ways? Thank you for your help!
Comment: The Rules Cyclopedia is a good option if you want exact compatibility.
Answer: Current editions of D&D are not at all compatible with Basic D&D. The new editions are based on the old editions in a very tangential way, each one deliberately transforming the game compared to the edition that went before, but there have been so many superficial and fundamental changes to the rules that they are now completely incompatible. Any conversion between Basic/Expert/Master D&D and D&D 4th Edition or even 3rd Edition would be more of a re-imagining than conversion, and would take as much work as converting to a completely foreign system.
However, your actual goal is getting your son his own copies of what you're already playing. In that case, you're in luck! Lots of people never stopped playing those editions. "Retroclones" of them are readily available, often for free (if you're OK with digital PDF rules), and frequently in print at reasonable prices. These were created based on the principle that you can copyright a game's words but you can't copyright the rules, so people just rewrote the games. There is a thriving community built around these retroclones.
There is a long list of retroclones out there (the list of retroclones at Wikipedia is not exhaustive at all). For the closest one to Basic/Expert/Master (also known as "BECMI D&D"), the leading choice is Dark Dungeons, which is available as a free download and in print.
However, if you're OK with PDF-only options, you can actually still buy the Rules Cyclopedia (which is essentially the BECMI books all edited together into one volume) as a PDF from the current publisher (who bought TSR back in the late 90s).
Comment: @KRyan Eh, 3rd/4th/5th edition are different enough from Basic that suggesting GURPs or Dungeon World would be just as much change, so why suggest it. *I* play the same edition they're playing (with some modifications); it's not like games become obsolete. If it ain't broke (they're having fun & it's not out of print), no need to change games.
Comment: Perhaps also worth noting the alternate route (getting new-edition books for both father and son). Obviously, that's going to be harder to do cheaply, since Wizards is actively publishing and selling them, and it means losing much of what's already owned, but like I said, perhaps also worth mentioning.
Answer: No, it would not be, at least not easily.
But it's all a matter of degree.  Older versions of D&D, like BECMI (red box... immortals), are a little more cross-compatible with earlier and later versions from back in the day but it was still pretty different from say AD&D 1e. Each revision has gotten more different - 2e, 3e, now 4e, and 4e is probably the  most different of them all.  The Monster Vault is 4e and other than "mining it for ideas," it's not compatible with the other versions.
You can get him his own BECMI set, at least in PDF, because Wizards is selling their older editions again at http://www.dndclassics.com/.  Or, you can get him started on a newer version - 4e, or actually it might be better to just start with the free D&D Next (5e) playtest - it's actually more back compatible than 4e is and inherits some of the Basic/2e approach.
There are all the retroclones, but I'm not sure why you'd get one of those when the originals are available again.  See Overview of D&D retro-clones for some options there.
Though the new D&D market leader isn't even D&D any more, it's a variant called Pathfinder and is preferred by many.  It has a beginner box product and a large well supported game line.  You can check that out too.
Comment: I recommended an in-print retroclone because "getting copies for my son" when he's got his own probably indicates a hardcopy preference.
Answer: Unfortunately, no.
But if you have a preference for hard copies and would like to get as close to the original intent of old-school Dungeons and Dragons without a box set or retro "clones", you can actually buy hard-back (non-pdf, genuine dead tree) reprints of the both the original Advanced Dungeons and Dragons 1st Edition and 2nd Edition rule books from Wizards of the Coast.
1st Edition
http://www.wizards.com/dnd/Product.aspx?x=dnd/products/dndacc/02410000
2nd Edition
http://www.wizards.com/dnd/Product.aspx?x=dnd/products/dndacc/35760000
Personally, being my introduction to RPGs in general, I would highly recommend this avenue. They are much more likely to be in line with what your are describing rule-wise and in game tone.
That said, one advantage of purchasing the PDF-only Dungeons and Dragons Rules Cyclopedia as mentioned by SevenSidedDie is for it's "extra features" including:

Rules to convert D&D games and characters into AD&D 2nd edition game statistics and back again

Thus you and your son could have the best of both worlds.
Thanks to SevenSidedDie for pointing out both editions were available as reprints, and that indeed, Advanced 1st Edition is even closer (more compatible) a rule set to Basic D&D than Advanced 2nd Edition.
Comment: There are also [1st edition AD&D reprints](http://www.wizards.com/dnd/Product.aspx?x=dnd/products/dndacc/02410000) in hardcover, which is an edition closer to BECMI D&D than 2nd edition AD&D. It's also worth noting that Wizards of the Coast considers the old edition reprints "premium"; they cost a bit more than they otherwise would, and have fancier faux-leather covers and such, because they're aimed at collectors as well.
Comment: @SevenSidedDie I was unaware that they also did 1st Edition reprints. Nice to see. And yes, they would be even closer to the original Basic D&D box sets.
Answer: The simple answer is that there are three board families of games branded with D&D.
Classic D&D which includes OD&D, Mentzer's BECMI D&D, AD&D 1st, AD&D 2nd and current playtest version of D&D 5e/Next.
D20 D&D which includes D&D 3.0, D&D 3.5, and Pathfinder
D&D 4e, D&D 4e Essentials
Understand there are differences but they are a matter of inches and within each family support material generally just work as is.
D20 D&D and Classic D&D can use each other adventures and settings with a little work.
D&D 4e settings and adventures can be used with earlier editions with work. However the balance of Monsters is very different but on the plus side 4e adventure often come with battlemaps and other useful props. The reverse unfortunately is not often true due to amount of time it takes resolve a combat encounter. The dynamics of 4e Powers and Healing Surges means that combat often takes longer to resolve than earlier editions.


Can I download Raspbian update packages on a Redhat Linux Server?

Question: I have a Redhat Linux Server that I'm running and I'm trying to create a update repository for Raspberry Pis, is it possible to download the update packages to my Redhat server, and if so, how?
Comment: Why don't you just mirror http://raspbian.raspberrypi.org/raspbian/ and sync it daily?  I don't think there's anything more to it than what you see there (the package manager on the client uses http exclusively AFAICT).  You can then use your repo in place of it in apt sources as per Ingo's answer to your previous question.
Comment: Thank you @goldilocks, I will give this a shot, do you have a link how I would go about mirroring that site?
Comment: No.  Probably a better question for our larger sibling site, [Unix & Linux](http://unix.stackexchange.com/).
Answer: Cloned my previous answer.
Raspbian is a derivate from Debian and it also uses Debians infrastructure. As far as I understand you want to setup your own package repository like that one used by Raspbian and Debian. First of all: the used repositories are configured in /etc/apt/sources.list and in files in directory /etc/apt/sources.list.d/. On Raspbian there are two files by default:
rpi ~$ cat /etc/apt/sources.list
deb http://raspbian.raspberrypi.org/raspbian/ stretch main contrib non-free rpi
# Uncomment line below then 'apt-get update' to enable 'apt-get source'
#deb-src http://raspbian.raspberrypi.org/raspbian/ stretch main contrib non-free rpi

rpi ~$ cat /etc/apt/sources.list.d/raspi.list
deb http://archive.raspberrypi.org/debian/ stretch main ui
# Uncomment line below then 'apt-get update' to enable 'apt-get source'
#deb-src http://archive.raspberrypi.org/debian/ stretch main ui

You can browse the repositories with http://raspbian.raspberrypi.org/raspbian/ and with http://archive.raspberrypi.org/debian/
The former repository is mainly the Debian repository http://ftp.de.debian.org/debian/ just compiled for armhf. The latter repository is from the Raspberry Pi Foundation and contains specific software to run the Raspberry Pi hardware, e.g. the kernel, firmware and drivers. This could be an example for your setup.
I do not have made a Debian repository before so I can give only some pointers. Here I have fond an entry for a Debian Repository Setup. You also can google for "how to make a debian repository".
Comment: Yes that's correct I'd like to set up my own package repository, however I will be setting up the package repository on a Redhat Linux server, are the infrastructures compatible? @Ingo
Comment: @Jbro1945 I don't know. Redhat uses its own package management system with rpm packages. But it should be possible to install foreign software from Debian by hand and run it.
Comment: I don't think the OP needs to install any .deb packages on the RH server (which is potentially possible, but requires you pull the packages apart and check library linkage, etc.) -- the software from that setup page such as "Dak" are fetched from git repos.  WRT "the infrastructures", the infrastucture in this case is an HTTP(S) service, which is platform agnositic.


Civicrm 4.7.20 Register event participant - pay by creditcard

Question: just updated to civicrm 4.7.20 - I wanted to register a late event participant used Register Event Participant in the past.  I can select the event and price but if I check 'record payment' the payment block with CC #, ccv and expiry doesn't come up. I did this once and seemed to get the Contact info page plus a link to enter credit card information.
What is the correct way to get the payment block (not just the priceset for the event) to come up?
Comment: FYI when I test in the sandbox and select credit-card payment I only get a box for 'last 4 digits' of the card - but I want to submit  the  actual payment, full CC number, CCV and expiry.  How can I record a credit-card payment for an event on behalf of an attendee?
Comment: Hi Lesley - are you able to either Accept Karin's answer, or add your own and Accept that so this can be closed off
Answer: From a Contact's summary page -> hit the Events tab

-> then hit the Submit Credit Card Event Registration button - and select an Event. If it's a paid event and you've got a Payment Processor setup/selected that handles Credit Cards - then the Credit Card fields will appear:
Comment: Thank you, KarinG, I had tried this from just Reg.Event Part w/existing contact. When I tried this from the Sandbox (which I assume you did here) it worked as you showed.
Comment: Excellent - glad I could help you out.
Comment: hmm, it seems like if I have several payment processors defined and set one as a 'default', there's no dropdown for payment processor AND the credit card info block isn't shown. If I go into Admin/Payment Processors and make none of them the default, the dropdown for pay.processor shows and then I get the CC info block.
Comment: In the sandbox there's only 1 pay. processor (Test) and you can't add any there. seems like a bug - I can try fixing it.


Draughts: King required?

Question: Can one be compelled to use his king when there are alternative moves? Especially if that move will end up having the king killed. My opponent saud I was obligated to use the king.
Answer: No. You are never obliged directly to use a specific piece to move.
The only exception is trivial: a game played under forced capture rules where there is exactly one piece able to make a capturing move.
Even then, if that piece has a choice of captures, the player may choose which capture to make.
It is likely your opponent has either confused this rule with another, has played in environments with this uncommon variant rule, or the king had a capture available and no other pieces did.
Comment: There's a second variation where you are required to make the best capturing move.
Answer: You are not obligated to use a king because it is a king. There are however rules variants for checkers/draughts that obligate you too make captures when possible. there are two versions of this:

If you have a piece that can capture, you must use a piece to capture, and must continue to capture until that piece no longer has a legal capturing move.
If you have a piece or pieces that can capture, you must take the most captures you can with one of those pieces.

The second rule is harder to enforce, and harder to work with, but it does exist as a variant. It means you need to evaluate the best possible move when you have two choices of where to take before doing anything. If that king was the only piece that could make a capture, your opponent may be correct, though it would depend on the rules variant.

Draughts: King required?


Finding user using an email address

Question: I might be ignorant if there exists such functionality. Can I search for a friend on Stack Exchange with their email address?.
Comment: Email addresses on SO are private. We'd like to keep it that way.
Comment: Normal users like us can't do it, but moderator can do it for some cases.
Comment: If you know their email address, there is a good chance they are using either their real name, or the username of their email address as their display name on SO
Answer: Luckily, no.
If they're your friend they can tell you their username in person, therefore your question seems to imply they're not your friend. There's no reason at all for you to know who is your friend on Stack Exchange apart from to engage in voting fraud; so, I don't see the need for this feature. Each site should be about the quality of the questions and answers not who wrote them.
Stack Exchange is not a social network.
Answer: Actually, you can.
By taking the md5 hash of your friend's email address, you can search the data explorer for other users using the email they used for their gravatar. This isn't foolproof, of course, since the email they used for the gravatar can be different from their usual email.
Though see Ben's answer for why this isn't a particularly good idea. I'm not entirely sure why you can't just, you know, ask your friend for his Stack Overflow username.
Comment: why doesnt it work for me

Finding user using an email address


Europe -> Mainland CN -> Taiwan max Cash?

Question: According to here / here you need not declare up to $5'000 cash entering China / up to $10'000 entering Taiwan. What if I am transiting Beijing on my way to Taipei?
Comment: Are you passing through PRC customs?
Comment: @SpehroPefhany: I hope to spend the layover time outside the airport, that probably means "yes" (I am not planning to leave much money in PRC though).
Answer: Since you are planning on passing through Chinese customs you will have to declare whatever you are carrying (including cash) in accordance with Chinese law.
Declaring it does not necessarily mean that you are not allowed to take it, it just means they want to know about it (and if you fail to declare it, you might forfeit it, or worse). This, apparently official, site says:

RMB20,000 cash or above, or any other foreign currencies in cash equivalent to US$5,000 or above.     Items will be dealt with according to the current regulations.
Passengers carrying foreign currencies in cash worth more than US$5,000 and intending to take the currencies out of China in the future shall fill out two declaration forms. After being endorsed by the Customs, one copy of the declaration forms will be returned to the passengers for future use at the time when leaving China.
Comment: I see. What might be the likelihood that I need to show the cash to the customs at some point?
Comment: Just a guess- pretty good chance that if you declare something they might want to see it.


How can I record a push button sequence and store it in an array

Question: I have 3 push buttons and I want to record the sequence in which they are pressed in array of size 10,i.e, I want to record 10 values for example {1,1,2,2,3,3,1,1,1,3}. I want to blink an array of 3 LED in the same pattern in which the buttons were pressed. I have two extra push buttons for putting the arduino in record and play modes respectively. If any one can suggest how I can store the values in the array I will really be very thankful. I am also facing the problem because it's very difficult to manage the bouncing of the buttons simultaneously.
Comment: Like `button1[3]=readAndDebounce(PIN_BUTTON1);`?
Comment: is it possible to show your wiring pattern?
Answer: You can create an array like this, make it global to easy access it:
int states[10];

And the current index:
int index_state = 0;

And initialize the array (in setup):
for (int n = 0; n < 10; n++)
{
    states[n] = 0; // Unpressed
}

When a new button press should be stored:
states[index_state] = state;

And add one to the index state, if 10 is reached, start over (this means the last 10 are stored).
index_state = (index_state + 1) % 10;

And to check the states you just iterate from index_state.
Hope this helps you get going.
Note this is called a ring buffer.
Comment: thanks a lot. It helped me store the button sequence. If you can please suggest me how can I blink the LEDs in same sequence as stored in the array with an delay of 500 millisecond. I am posting my code in the answer section please have a look.
Comment: The delay of 500 ms might be tricky. That means that for every button you press, you also have to store the time. So you can check if 500 ms have been passed since that press and blink the corresponding LED. Maybe it helps do create the program first for one button and one LED (with 500 ms delay) and than add more buttons/LEDs. Mostly it's better to gradually extend the program instead of going directly to the end goal.
Answer: this is my code that stores the button sequence but it will be great if someone can help me blink the LED sequence an put the micro-controller in play or record mode when desired. Also this code faces some issue as some times it fails to take inputs or takes two inputs at a time:
int arr[10];
boolean previous = LOW;
unsigned long time1 = 0;
int debounce = 200;
unsigned long time2 = 0;
int index_state = 0;
void setup()
{
 for(int i = 3;i<6 ;i++)
  pinMode(i,INPUT);
 for(int n=0;n<10;n++) arr[n] = 0;//initialisition
 Serial.begin(9600);
}

void loop(){
 boolean mode = digitalRead(3) || digitalRead(4) || digitalRead(5);
 while(mode == LOW) mode = digitalRead(3) || digitalRead(4) || digitalRead(5);//wait here till one of the pushbutton goes high;
 //Serial.println("value");
 if( mode == HIGH && previous == LOW && millis() - time1 > debounce){
 //find out which one is high and store that value in array;
 if(digitalRead(3)) arr[index_state] = 3;
 else if(digitalRead(4)) arr[index_state] = 4;
 else if(digitalRead(5)) arr[index_state] = 5;
 else ;
 //print the value and the index;
 Serial.print(arr[index_state]);
 Serial.print(" Stored in index: ");
 Serial.println(index_state);
 index_state = (index_state + 1) % 10;
 //update value of time1 for button debouncing
 time1 =  millis();
}

  //update the value of previous button state
  previous = digitalRead(3) || digitalRead(4) || digitalRead(5);

  }


Integrating Wordpress with Spring MVC

Question: I'd like to have a Wordpress installation to serve blog content for my site under the directory /blog
My site runs on Spring Mvc and I'd like of course to maintain the basic layout (saying Header and Footer) of my site and integrate the wordpress blog on it.
What could be some approach to do this?
I'm using Tiles as my Template mechanism so I was basically thinking to handle /blog request with my requestDispatcher and internally forward the request to Wordpress, then take the response and stream it inside the Content Tile section of my pages so to keep the basic look of my site for header and footer.
But I'm not sure of this approach.
How are you doing this? I can see they also have some RestAPI
Answer: If you simply want to use WordPress as a content management system and Spring MVC + Tiles to display your blog, then exposing your WordPress pages and posts with an API plugin such as WP Rest API or JSON API sounds like a great solution. This is how we manage our faq/contact/terms and conditions/etc. pages.
To make it faster, we synchronize (with a CRON job) each 30 minutes the content between our application database and the WordPress instance so that when the page is requested by an user the content is not pulled from WordPress but from the application DB. And then to make it even faster we created an Hibernate cache that lasts 30 minutes for this kind of data.
Answer: I have recently written a library in Spring, that uses WP REST API plugin to fetch content from WordPress. You might find it useful. Here is blog post on how to integrate Spring Boot and WordPress.

Integrating Wordpress with Spring MVC


How to store data from a ListModel?

Question: Is there some sort of standard or commonly-used way to store data in elementary apps? I currently have a bunch of GObjects contained in a ListModel and would like to persist that to the disk and reload it when the app opens again. The Settings object doesn't seem like quite the right place for it as it's an unbounded chunk of text data from user input. Should I just stuff it in a leveldb instance or something? Or is there a better option?
Answer: I used a json array to save some data for an application I'm building. The data is saved in a file in the user's .config folder. Take a look at the writeServers method.
If you go over the entire file, you'll see that it first verifies that the file exists, and creates it if it does not.

How to store data from a ListModel?


I thought this was a good question: Certifications required to become a PM

Question: I know it polls and there are no unequovical, definitive answers; however, it seems to me that there would be value to hear the opinions of various practitioners: pros, cons, what we do know about them in terms of hiring filters or performance indicators, etc.  Thoughts?
Comment: Ok David, I still think we need more details from the asker, but let's try your experiment with the modified question:  http://pm.stackexchange.com/questions/6161/are-certifications-important-to-becoming-a-pm. I'll reopen, but feel free to edit further if we can make it better.
Answer: I do agree this question could be valuable. But right now, he's pretty much asking for a list of people who know project managers with/without certifications. As it stands, it's not valuable... but like you said... it could be!
I was hoping the asker would come back and maybe be a little more clear about asking for definitive answers. However, I see that's sort of tough to do because of the nature of the question.
I'm off work now and will spend a little editing time to see if I can push it back over the line of constructiveness. Feel free to jump into chat if you're around and we can maybe figure it out together.
As a community, we're still trying to figure out what's best for our site. If we can do anything to improve questions at this point, even if it doesn't make them perfect, that to me seems like a good enough justification to reopen them, if nothing else but to have more data to look at during evals.
Would it help if I indicated in the comments on closed questions that I think other editors could possibly help salvage the question? Would this help encourage more community editing?
I'm going to change the question a bit and try to guess what he's really after. Without the asker in this case, all we can really do is hope we preserve the spirit of the question.


bartik subtheme and css

Question: I want to make some modifications to the bartik theme i am using D8
(like changing the logo position,etc) i created a subtheme
named it "mytheme"
following the instruction i found here:
https://www.drupal.org/docs/8/theming-drupal-8/creating-a-drupal-8-sub-theme-or-sub-theme-of-sub-theme
So, first I created the mytheme.info.yml file containing:
name: mytheme
type: theme
base theme: bartik
description: subtheme for bartik
core: 8.x
libraries:
  mytheme/global-styling
regions:
  header: Header
  primary_menu: 'Primary menu'
  secondary_menu: 'Secondary menu'
  page_top: 'Page top'
  page_bottom: 'Page bottom'
  highlighted: Highlighted
  featured_top: 'Featured top'
  breadcrumb: Breadcrumb
  content: Content
  sidebar_first: 'Sidebar first'
  sidebar_second: 'Sidebar second'
  featured_bottom_first: 'Featured bottom first'
  featured_bottom_second: 'Featured bottom second'
  featured_bottom_third: 'Featured bottom third'
  footer_first: 'Footer first'
  footer_second: 'Footer second'
  footer_third: 'Footer third'
  footer_fourth: 'Footer fourth'
  footer_fifth: 'Footer fifth'

Next i created the mytheme.libraries.yml containing the following:
global-styling:
  css:
    theme:
      css/style.css: {}

i went to appearance and enabled "mytheme" as default, went back to site, looks identical to how bartik was
so far so good
my problem now is, how do i move on with the customizations i want to do?
i created a folder called: "css" in "mytheme" directory, inside the css folder i created a blank file called "style.css" and
there i wrote the first modification i want to do
.region-header .site-branding {
    float: none;
    text-align: center;
}

When i go back to site i see no difference, the logo remains on the left like it was on bartik
Can somebody help please?
I am not sure how to proceed and if what I did by creating a css folder, etc is the right way.
Thank you.
Comment: Just to be sure: did you change to your new theme in `admin/appearance` and did you clear cache?
Comment: yes, i did set as default the new theme and i cleared the cache
Answer: Not sure if this is still relevant or not but I was having the same issue and I was just missing a dash.

libraries:
    mytheme/global-styling

to

libraries:
    - mytheme/global-styling

bartik subtheme and css


Rooting Bougainvillea in water?

Question: How long does it take for bougainvillea to grow roots in water? How long should they be before I transplant?
Answer: I successfully propagate bougainvilleas in water, but there are some tips:

Choose cuttings that are almost hard (to avoid rotting in water).
Put them in a small size paper cup half filled with water; remember that wide opening of cups help evaporating water, so keep the appropriate humidity.
After 2 days when the water level decreases, add some dilute iron powder solution in the cup so the color changes to almost red but you can see the bottom
Remember that the small white dots appear on the body of cuttings after 10 to 20 days, these are not roots but good signs of doing well.
Wait until real roots emerge from the bottom of cuttings, about 2 months or more after preparing the cuttings. Wait another month or more until the roots become between 2 to 3 inches long. You will see that roots go around the bottom of the cup. New growth and fresh leaves are another signs of this final stage.
Put the rooted cuttings in a well draining clay pot and water thoroughly.
More important tips:

a) best time for taking the cuttings is during or after flowering.
b) best temperature for this method is about 22°C (72°F).
c) keep checking the water level inside cups and add water and iron solution when needed.
d) to avoid fungus remove any leaves that fall inside the cup from cuttings as soon as possible.
e) keep the cuttings away from direct sunlight, very little filtered sunlight is enough.
f) keep the pots in the same place that you keep cuttings for several days and move them gradually to the full sun, otherwise your cuttings will wilt after potting due to changes in humidity and temperature.
This was my 3-year experience of propagating bougainvilleas. Believe or not, it is 10 times more successful than other methods like putting the cuttings inside potting mixture or even using rooting hormone and I sure hope this will help you.
Answer: I'm not at all sure it will produce roots in water, I think it's very unlikely, though someone else might know different. The usual method is from non flowering, softwood/semi ripe cuttings in summer, or hardwood cuttings in winter, or by layering. This thread https://garden.org/nga/searchqa/answer/9679 gives pretty good instructions in regard to all three of these. Note they don't like root disturbance, so when your cutting starts growing eventually, be careful not to disturb the root system too much when potting on or planting out.
Comment: Yes you can root bougainvillea in water, I actually have a root, it's actually getting quite long, approx 3".  I was just not sure how long I should let it get before I transplant it in dirt.
Comment: Oh, okay, well pot it up now then, but into proper potting soil, preferably, and not too big a pot - pot on into a bigger pot as  necessary till its big  enough to cope in the ground.
Answer: Yes, you can root them in water. I actually have had more success doing it this way rather than in soil for some reason. I make sure I keep the water fresh by changing it other days. I actually have cuttings with lots of leaves growing and one even has a flower. I have about 12 cuttings from 3 different Bougainvillea and they all are showing root growth and have loads of leaves sprouting.
Answer: I am also researching about the best way to grow bougainvillea.  If the cuttings are developed in water it's best to add the soil you intend growing them on with, to the water gradually to avoid planting shock. Use the same water the roots have developed in, but add the soil very slowly, over a period of four to six weeks depending on pot size, the slower the better, (apparently).
What I am going to try is is put sterilised tiny pots into the pot, or whatever you wil use to contain the water, stand it on another upturned pot, then use the same growing medium that they will stay in, then as you slowly add soil the pots will be slowly filling. To prevent the soil from falling straight through, using the base of the pot as a  guide I cut circles of  kitchen paper, put two together, and fit them inside the base of the pots I have done this successfully many times (the kitchen paper that is). The roots grow through it no problem. Good Luck.

Rooting Bougainvillea in water?


How do I remove many system roots from Apple System Keychain?

Question: The Apple keychain application will not let you remove system roots, it will only allow you to disable them. It will only allow you to disable them one at a time. For each one, you need to go through 3 UI panels and type your password. Is there a way to either automate this or do it all at once? I do not like Apple's current selection of system roots.
Comment: My goal is to remove trusted roots from organizations that I don't trust. I do not trust the government of China. I don't trust the compromised certs from the Netherlands. I don't trust certs from a whole bunch of other organizations. I don't want them.  Why should I trust all of those organizations? I don't.
Comment: I'm looking to find/develop a good list of certs not to trust, and their hashes, which would be handy for distrusting 'em. Seems to me like a good idea to distrust ones not seen regularly outside specialized niches. Maybe netcraft has a list of widely used CAs developed via [their survey](http://news.netcraft.com/ssl-survey/) to determine which are widely used. I'm betting that with around a dozen CAs, I'd have the top 500 sites and all the sites I visit regularly covered. vy32, I'm curious if you have your list of certs you decided not to trust, and why you selected them. Can you share? Also,
Comment: I can't give you an answer/solution, but I can suggest you re-think this.  What do you hope to accomplish/What is your goal?  What are the advantages of doing this?  What are the disadvantages of doing this?  If it is just a matter of wanting to clean up Keychain, I'd forget it. Altering ANYTHING dealing with "system" can lead to problems, and is generally not recommended.  It's one of those "if it ain't broke, don't fix it" situations.
Comment: How do you find out which certificate belongs to which application?
Comment: Certificates don't belong to applications. They belong to the system.
Answer: Backup keychain before trying anything.
Listing root certificates:
sudo security dump-keychain /System/Library/Keychains/SystemRootCertificates.keychain

Just look in a dump for a names or SHA-1 hash values of certificates that you want to get rid of and write them down.
Now you can delete that root certificates using security delete-certificate command.

Usage: delete-certificate [-c name] [-Z hash] [-t] [keychain...]
-c  Specify certificate to delete by its common name
-Z  Specify certificate to delete by its SHA-1 hash value
-t  Also delete user trust settings for this certificate The certificate to be deleted must be uniquely specified either by a

string found in its common name, or by its SHA-1 hash. If no keychains
  are specified to search, the default search list is used.

For example you can delete chinese root certificates using this command:
sudo security delete-certificate -Z 8BAF4C9B1DF02A92F7DA128EB91BACF498604B6F /System/Library/Keychains/SystemRootCertificates.keychain

Comment: When the list of root certificates is dumped under what attribute do I find the SHA-1 hash value?
Comment: @BrightIntelDusk you can use the following command: `sudo security find-certificate -a -c startcom -Z /System/Library/Keychains/SystemRootCertificates.keychain`
Answer: Thank You! Worked for me with the -c option. Find the name of the root certificate in Keychain.app, then sudo security delete -c "CERTNAME" /System/Library/Keychains/SystemRootCertificates.keychain
If you keep Keychain.app open with that certificate in view, you notice it immediately deletes when executing the command in terminal.
Answer: Distrust of a root with delete-certificate by hash is broken: sudo security delete- certificate -Z 8250BED5A214433A66377CBC10EF83F669DA3A67 / System/Library/Keychains/SystemRootCertificates.keychain This always fails with: "security: SecKeychainItemDelete: UNIX[Operation not permitted]" even if this referenced certificate is present.
Here's a workaround from a talk at DEFCON24.
Instead save the root certificate as a cer file and use: security add-trusted-cert -d -r deny -k "/Library/Keychains/System.keychain" certname.cer
Answer:
Open Keychain Access app (/Applications/Utilities/Keychain Access.app)
Select System Roots in keychains
Select Certificates in category
Search for the expired certificate's name
Right click on the certificate then select "Delete"
Enter system admin password
Comment: This does not work anymore since el capitan due to system integrity protection. However you can choose not to trust.


Is the Star Wars galaxy plausible?

Question: There are a ton of planets in GFFA that can support life. There are tons of exoplanets in our own Milky Way Galaxy have no sign of life. So is the Star Wars galaxy plausible with its so many planets full of sentient life, or is it truly a work of implausible fiction?
Comment: This question is not off-topic. The plausibility of plot elements in science fiction is well within the range of acceptable questions. It shouldn't be shunted off to some science-focused SE either, since correct answers will depend (as often as not) on the internal consistency of the work in question.
Comment: The question is whether it's *scientifically* plausible. That per-se is beyond the scope of the site.
Comment: @Richard What other form of plausibility is there? If you're going to redefine plausibility, then the answer to this question will be yes. If you're not, then it will need to be answered within the scope of a scientific and evidence-based discussion. Not saying that this necessarily means we should close the question.
Comment: @Richard They're off-topic **unless they related directly to a cited work of fiction**, like Star Wars, as this question does.  The question is asking about whether something _in-universe_ is plausible.
Comment: The essence of the question is "is this a scientific possibility, please explain why using science jargon"
Comment: @Izkata - He's not asking "why are so many planets in the Star wars universe populated?", he's asking if it's possible **in our galaxy**. It's a straight science question about the Drake Equation.
Comment: @Richard That's a different tangentially related question, but the point here is that it _requires_ SciFi/Fantasy domain knowledge to answer.
Comment: @Richard - it's not too different from this ["is Middle-earth plausible?"](http://scifi.stackexchange.com/questions/26808/how-exactly-is-arda-supposed-to-be-an-ancient-earth) question, which could also be argued to be a straight science question about continental drift, geology and rising sea-levels.
Comment: The most implausible point is that on all those planets there is a woman who will marry a fellow who compares her to *sand*.
Comment: Just by making a comparison to the real universe makes it off topic, since questions that deal with if a technology or setting is realistic are off topic (or were last I checked).
Answer: Some astronomers now suspect planets around nearly every single star. There are 300 billion stars in the Milky Way. We know of very few exoplanets, and we tend to see only the larger ones. Quite possibly, those same star systems have smaller, more amenable planets.
What we know so far is such a small sample size of the whole, that I don't think it can in any way be representative of this galaxy.
Now, it's unclear whether sentient life is typical on a life-bearing world. So perhaps they exaggerate a bit on that front. But if they have 1 million species in that science fiction universe, it would still only be 1 per 300,000 stars. Additionally, an intragalactic economy might go far to preserve sentient species that would go extinct on their own... thereby boosting the numbers you'd see. This is speculative, but in a galaxy where faster-than-light travel is possible and there are thousands of sentient species zipping around, might they not have decided to take action to prevent the extinction of Neanderthals on our own world?
Of all the highly implausible things that are depicted in Star Wars, I do not count the depiction of numerous sentient species to be one of them.
Comment: @Kalissar I'm sure they're capable of large-scale (and rapid) terraforming if they can build megastructures like a death star. Not sure there's a point though, when there are likely many ready-to-go worlds to pick from.
Comment: Very good answer, but it lacks a single yet essential detail for my +1 : you didn't mention colonization nor terraforming as part of the SW universe and yet, I'm sure people with such advanced technology would be able to make small-but-hostile planet a nice home for new species
Answer: When you say "tons of exoplanets in our own Milky Way Galaxy have no sign of life", you are referring to the state of knowledge in astrophysics today. This, as any examination of the history of science shows, can change.
A lot of what we accept as "facts" from science are merely "the closest assessments available today". No one on Earth has been on those planets and near those stars to determine if there is life, all we can do is suggest models that take our own experience - our own planet with our own species - and project that onto the the galaxy. "That planet is close to its sun, and if that had happened here, it would probably be too hot for creatures like us". There are a lot of assumptions made here - assumptions freely admitted by the scientists themselves, though they tend to get blurred when reported - that these "no sign of life" planets are only blacklisted for very specific signs of life, in very specific conditions.
So the explosion of life-supporting planets in the GFFA isn't really implausible, as long as you accept the basic assumption that what we know today isn't the whole truth. And that's an assumption that you have to make for science fiction in general. And, to be honest, for science, too.
Answer: Yes, it's plausible, given our current knowledge.
If we lived in the Star Wars galaxy, assuming no direct contact with other civilizations, it would look much like this one given our current technology. We'd have started being able to detect exoplanets only recently, but only ones that are very large and/or very close to their stars -- just as we're doing here and now.
We might know about the gas giant Yavin if it were close enough. We wouldn't yet be able to detect its habitable moon Yavin 4.
Just recently, we've already started detecting planets with just a few times the mass of Earth within their stars' habitable zones. But we just don't know whether they actually support life, because we haven't yet been able to examine them closely enough. Kepler-22b could be swarming with Ewoks for all we know.
We don't actually know that there are other Earth-like planets in our own galaxy, but given the distribution of planet sizes and orbits in our own Solar System, and of the subset of exoplanets we've been able to detect, it's very likely that there are plenty of them. It's entirely plausible that our own galaxy is as rich in habitable planets as the Star Wars galaxy.
There is at least one one visible difference. The Star Wars galaxy is home to a galaxy-wide civilization with easy faster-than-light travel (an Empire or a Republic, depending on when you ask). Most civilizations would have been contacted by now, and probably annexed. The Empire certainly had no qualms about setting up bases on primitive inhabited worlds, such as the Forest Moon of Endor.
But given that we have just a single example of a galaxy with no apparent galaxy-wide civilization, that doesn't make the existence of such a civilization in another galaxy implausible.
Answer:
There are tons of exoplanets in our own Milky Way Galaxy have no sign of life.

Yes, but about 1% of them do exist in what we refer to as the "Goldilocks Zone", where liquid water can exist. Just because 99% or more of all planets couldn't possibly harbour life (among those that we've found, most of them are so hot that you could melt iron and rock on the surface - we've found planets hot enough to evaporate sand - and thus rain liquid glass), doesn't mean that life is not abundant in our galaxy. You just have to remember that the numbers are literally astronomical. There are hundreds of billions of stars in our galaxy. If 1% of them have life, that means there's billions of habitable worlds out there. If 1% of those have life more advanced than bacteria, that narrows it down to "only" hundreds of millions of worlds with plants and insects. If 1% of those have intelligent life capable of forming civilizations, that still means there are millions of planets with such. And we're now talking about a ratio of 0.0001%! For space-faring civilizations to number in the hundreds or even thousands in an area as large as a galaxy, the chances of that don't have to be very high at all, even shrinking to infinitesimally small.
Answer: If I had to pick one least implausible thing about the star wars universe, it might be the proliferation of different sorts of life in it. Some of the forms might be less plausible than others - for example, the giant space worm from Empire seems a bit of a stretch - but the sheer number is exactly what you'd expect given the vast number of opportunities for life to arise, and the amazing capacity for life to adapt to wherever it finds itself.
On the other hand, among the more implausible elements of the star wars universe is the fact that these life forms meet and interact. So depending on whether you're interested in the raw number of forms of life or the number of different sorts of aliens in the Cantina, my answer is either "yes, it's quite plausible" or "no, it's a complete fantasy".
Answer: We've only been to one of the hundred(s) of billions of star systems in our own galaxy, so I don't think we're qualified to say "how plausible" a galaxy with many species in it is. Also, as far as I know, we don't know the history of race proliferation in the Star Wars galaxy. The fact that many of them are very human-like or at least humanoid, may suggest that many races may have originated on one planet long, long ago, and spread around to different planets long, long before the events shown in the films.
The most implausible thing about the life forms in the films, to me, is the depiction of the water creatures in Episode I, when Obi-Wan and Qui Gon are taking a submarine on Naboo, to meet Jar Jar's New Orleans-esque underwater people (...which also re-destroyed my credence, for other reasons...). During the submarine ride, we are shown a series of increasingly-large "fish" swallowing each other, while the Jedi *cough*nonsensically*cough* "impress" us with their lack of concern. That scene was a peak of implausibility for me, because unless they were just there for an incredibly unlikely and infrequent event, I can't imagine that any environment could sustain that phenomenal rate of biological destruction, because of the time surely required to generate the larger fish, shown being destroyed in seconds. All I can think (besides that it was done in a lame attempt to impress audiences assumed to be dumb and in need of excessive spectacles) that might make that plausible, would be if those creatures don't actually digest each other, but instead are about to vomit each other out alive, or they do some bizarre reformation after swallowing each other.

Is the Star Wars galaxy plausible?


If in t-SNE digaram of binary classification both classes follow the similar curve what does t-SNE diagram show?

Question: If in t-SNE digaram of binary classification both classes follow the similar curve  what does  t-SNE diagram show for instance: Figure1 or  Figure2
Answer: To have intuition, let's make simplify the problem. Let's say that you are using PCA and that you are getting a linear function.
If you don´t get any clusters it means that it is not possible to separate them by linear combinations of the features that you have. And since it is a linear function, as you move in this direction there is a change in the variance.
t-SNE is similar to PCA but it does nonlinear combinations of features. And the dimensionality reduction that you have maintains the variance in a nonlinear way.
So just change the world linear for non-linear in the second paragraph to answer your question.
By the way, this doesn't mean that if you make a classification problem with Machine Learning you are going to have bad results. ML can still work in this case.
Answer: T-SNE is not a clustering algorithm and should mainly be used for data visualisation as authors outline in the abstract of their paper (you should read it: http://www.jmlr.org/papers/v9/vandermaaten08a.html). It has been show that it can separate well-defined clusters, which is not the case here.
There is no immediate separation between frauders and non-frauders on your main data. Basically your graph say that frauder and non-frauder are a part of a similar class with overall similar properties. So basically it means that the frauding characteristic is not immediate. Other ML algo may or may not be able to learn on 'secondary' variables.


Redirect user to specific link after login

Question: I am new to wordpress so I will surely need more help than others to understand your answers. So, the question is:
I have this website with a login page on home. Let's supose you are a member. If you want to log in, you should put your username and password, right?
Let's suppose your username is Malcovich. After you put your username and password, you click on "enter the website" button, and immediatly you will be redirected to www.mywebsite/MALCOVICH

How can I do that? How can I redirect people after log in to a specific page that is named as the username they use to access the website?

And also I want to put a voice "PROFILE" in the menu that does the same thing, redirects people to a page named as their username. And I want this button in menu to be seen only by loged in people.

Thank you very much for being my saviors
Answer: The login_redirect filter should works (add this code into your theme functions.php):
function my_login_redirect( $redirect_to, $request, $user ) {
    $redirect_to =  home_url($user->user_nicename);
    return $redirect_to;
}
add_filter( 'login_redirect', 'my_login_redirect', 10, 3 );

For "PROFILE" in the menu (add this code into your template file where you want to display it):
if ( is_user_logged_in() ) {
    $current_user = wp_get_current_user();
    echo 'user_nicename ) ) . '">PROFILE';
}

UPDATE: If you manage menu from backend, I don't know if any better solution, but this will works:
Add a custom menu item with name "PROFILE", and add this code in your theme functions.php:
function filter_nav_menu_items( $menu ) {
  if ( $menu->title == 'PROFILE' ) {
    if ( is_user_logged_in() ) {
      $current_user = wp_get_current_user();
      $menu->url = home_url( $current_user->user_nicename );
    }
    else {
      $menu->_invalid = true;
    }
  }

  return $menu;
}
add_filter( 'wp_setup_nav_menu_item', 'filter_nav_menu_items', 999 );

Comment: Hi, I'm really happy your advice worked perfectly. Now users are redirected to their own page after login. I have another question. Where should I put the code for the profile button in menu?
Comment: I updated my answer. It should works for you.


Append text while user is editing without disturbing user interaction

Question: In Windows forms and HTML textboxes, it is not possible to append text without influencing the current user action on the same textbox.
My usecase is that i get constantly new (from speech to text app) text and need to present the last 3 lines on a public screen. Those most recent 3 lines are subject to be changed by a human live editor. All actions the human editor does are visible for the public viewers.
My current approach is to develop 2 applications, a sender and an editor app.
The sender app is receiving the inputs from the speech to text application which inserts sentence by sentence. The receiving application receives each letter/sentence and adds it to the editors textbox.
I cannot imagine that it works to just store and restore the carret position of the editors textbox when appending new text to the editors textbox.
Any idea how to make this work: constantly apply new text to a textbox that is currently being edited by human?
My current approach is to develop a "sender" and a "receiver" application. The sender takes the new content and posts it to the receiver. But how to insert the new text at the receiver side without influencing the current users interaction?
Basically google docs can do this but in my case the latency between sender and receiver textbox should be under 10ms or best without latency.
Comment: Well it definitely does not work to set caret position as i cannot control the time when users write stuff, nor can i block any user interaction. My current approach is to implement my own google docs...
Comment: "I cannot imagine that it works to just store and restore the carret position of the editors textbox when appending new text to the editors textbox" - did you try it? because that seems to be the solution to me
Answer: Don't allow 2 inputs at the same time: from receiver, from user keyboard. Allow only from keyboard. And other way must go to the second textfield. When user ends keyboard using (eg pause 10 sec), app can merge second field with main field. Then user begins using keyboard, and app gets text from receiver to second field again.
Comment: Sorry, cannot block any user at any time :-(


Is it possible to reconstruct the Hamiltonian from knowledge of its ground state wave function?

Question: Is it possible to "construct" the Hamiltonian of a system if its ground state wave function (or functional) is known? I understand one should not expect this to be generically true since the Hamiltonian contains more information (the full spectrum) than a single state vector. But are there any special cases where it's possible to obtain the Hamiltonian? Some examples would be really helpful.
Comment: In fact, even if you know *all* of the eigenstates, you still can't uniquely identify the Hamiltonian.
Comment: Related: [In quantum mechanics, given certain energy spectrum can one generate the corresponding potential?](http://physics.stackexchange.com/q/13480/).
Answer: IF you know that your Hamiltonian is of the form
$$
\hat H=\frac{-\hbar^2}{2m}\nabla^2+V(\mathbf r)
\tag 1
$$
for a single massive, spinless particle, then yes, you can reconstruct the potential and from it the Hamiltonian, up to a few constants, given any eigenstate. To be more specific, the ground state $\Psi_0(\mathbf r)$ obeys
$$
\hat H\Psi_0(\mathbf r)
=\frac{-\hbar^2}{2m}\nabla^2\Psi_0(\mathbf r)+V(\mathbf r)\Psi_0(\mathbf r)
=E_0 \Psi_0(\mathbf r),
$$
which means that if you know $\Psi_0(\mathbf r)$ then you can calculate its Laplacian to get
$$
\frac{ \nabla^2 \Psi_0(\mathbf r) }{ \Psi_0(\mathbf r) }
=
\frac{2m}{\hbar^2}\left(V(\mathbf r)-E_0\right).
$$
If you know the particle's mass, then you can recover $V(\mathbf r)-E_0$, and this is all you really need (since adding a constant to the Hamiltonian does not change the physics).
However, it's important to note that this procedure guarantees that your initial $\Psi_0$ will be an eigenstate of the resulting hamiltonian, but it does not preclude the possibility that $\hat H$ will admit a separate ground state with lower energy. As a very clear example of that, if $\Psi_0$ is a 1D function with a node, then (because 1D ground states have no nodes) you are guaranteed a unique $V(x)$ such that $\Psi_0$ is an eigenstate, but it will never be the ground state.

If you don't know that your Hamiltonian has that structure, there is (in the general case) no information at all that you can extract about the Hamiltonian from just the ground state.

As a simple example, without staying too far from our initial Hamiltonian in $(1)$, consider that Hamiltonian in polar coordinates,
$$\hat H=\frac{-\hbar^2}{2m}\left(\frac{1}{r^2}\frac{\partial}{\partial r} r^2\frac{\partial}{\partial r}  + \frac{1}{\hbar ^2r^2}L^2\right)+V(r),$$
where I'm assuming $V(\mathbf r)=V(r)$ is spherically symmetric, and encapsulating the angular dependence into the total angular momentum operator $L^2$.
Suppose, then, that I give you its ground state, and that it is an eigenstate of $L^2$ with eigenvalue zero (like e.g. the ground state of the hydrogenic Hamiltonian). How do you tell if the Hamiltonian that created it is $H$ or a similar version,
$$\hat H{}'=\frac{-\hbar^2}{2m}\frac{1}{r^2}\frac{\partial}{\partial r} r^2\frac{\partial}{\partial r}  +V(r),$$
with no angular momentum component? Both versions will have $\Psi_0$ as a ground state (though here $\hat H'$ will have a wild degeneracy on every eigenspace, to be fair). Carrying on with this thought, what about
$$\hat H{}''=\frac{-\hbar^2}{2m}\left(\frac{1}{r^2}\frac{\partial}{\partial r} r^2\frac{\partial}{\partial r}  + f(r)L^2\right)+V(r),$$
where I've introduced an arbitrary real function $f(r)$ behind the angular momentum? This won't affect the $\ell=0$ states, but it will take the rest of the spectrum to who knows where. (In fact, you can even tack on an arbitrary function of $L_x$, $L_y$ and $L_z$, while you're at it.)
A bit more generally, any self-adjoint operator which vanishes on $\left|\Psi_0\right>$ can be added to the Hamiltonian to get you an operator that has $\left|\Psi_0\right>$ as an eigenstate. As a simple construction, given any self-adjoint operator $\hat A$, the combination
$$\hat H {}'''
    = E_0 \left|\Psi_0\right>\left<\Psi_0\right|
     + \left(\mathbf 1 - \left|\Psi_0\right>\left<\Psi_0\right| \right)
        \hat A
        \left(\mathbf 1 - \left|\Psi_0\right>\left<\Psi_0\right| \right)
  $$
(where the factors in brackets are there to modify $\hat A$ into vanishing at $\left|\Psi_0\right>$ and its conjugate) will always have $\left|\Psi_0\right>$ as an eigenstate.

Even if you know all the eigenstates, it's still not enough information to reconstruct the Hamiltonian, because they do not allow you to distinguish between, say, $\hat H$ and $\hat{H}{}^2$. On the other hand, if you know all the eigenstates and their eigenvalues, then you can simply use the spectral decomposition to reconstruct the Hamiltonian.
In general, if you really insist, there is probably a trade-off between what you know about the Hamiltonian's structure (e.g. "of the form $\nabla^2+V$" versus no information at all) and how many of the eigenstates and eigenvalues you need to fully reconstruct it (a single pair versus the whole thing), particularly if you allow for approximate reconstructions. Depending on where you put one slider, you'll get a different reading on the other one.
However, unless you have a specific problem to solve (like reconstructing a Hamiltonian of vaguely known form from a specific set of finite experimental data) then it's definitely not worth it to explore the details of this continuum of trade-offs beyond the knowledge that it exists and the extremes I noted above.
Answer: Assume for simplicity that all the operators are bounded. If you know the wave function $\psi$ associated with the ground state of the unknown Hamiltonian $H$, then $H$ has the form
$$H = E_0|\psi\rangle\langle\psi| \oplus K$$
where $K$ is another Hamiltonian defined on a subspace of the original Hilbert space of co-dimension 1, and $E_0$ is the energy of the ground state, which we might as well assume to be zero (in particular, the spectrum of $K$ is bounded below by $E_0$). This shows that in general it is not possible to reconstruct $H$, since there is an infinite family of Hamiltonians $H$ parametrised by strictly positive self-adjoint operators $K$ that will solve the original problem.
Comment: So, if I understand it correctly, you mean a particular wave function can be ground state to many different systems (Hamiltonians).
Comment: Correct. A wave function is just a normalised vector in a Hilbert space. There are many operators on such Hilbert space that you can write that have this vector as an eigenvector.
Comment: Do you know of any very special example(s) where one can fix the Hamilton?
Answer: There's no analytic proof, but numerical evidence suggests that if you know that the Hamiltonian is local, and it satisfies the Eigenstate Thermalization Hypothesis (which most local Hamiltonians do), then you can extract the entire Hamiltonian from a single excited eigenstate, though not from the ground state: https://arxiv.org/abs/1503.00729.
Comment: Can you clarify what "local" means in this context? (Given the theme of my answer and Vladimir, you could take it to be a hamiltonian such that $⟨x_0|H|\psi⟩$ is uniquely determined by the values of $⟨x|\psi⟩$ at $x=x_0$ and possibly a neighbourhood around it, or even restricted to $⟨x_0|\psi⟩$ and a finite number of derivatives. However, if you're talking about the ETH and therefore about many-body hamiltonians, it could mean an entirely different thing.)
Comment: @EmilioPisanty In this context a many-body Hamiltonian defined on a graph of discrete sites is defined to be "local" if it can be written as a sum of terms with finite spatial extent.  In others words, in the form $\hat{H} = \sum_i \hat{O}_i$, where $i$ runs over the sites and each operator $\hat{O}_i$ is supported only on sites that are within a distance $r$ of site $i$, where the "radius" $r$ is an integer that does not depend on the total system size.
Comment: @EmilioPisanty So for instance the $\hat{O}_i$ might consist of first-, second-, and third-nearest-neighbor couplings.  The maximum number of neighbors away that are coupled can be arbitrarily large, but it must be *finite*, so that in the infinite-system limit each coupling only stretches an infinitesimal way across the entire system.  Then if you "zoom out" enough, the couplings can be made to appear arbitrarily short-range.
Comment: Yeah, I figured that would be the case. Given the level of the OP and the broad (HNQ) audience of this post, it's worthwhile including some of that explanation and context in the post.
Answer: If unknown part of Hamiltonian is potential $V({\bf{r}})$, then you can write a stationary Schrodinger equation and figure out what the potential should be.
Comment: Sorry, I didn't follow your suggestion. Can you expand your answer a bit?
Comment: You have $\psi$, you differentiate it $d^2/d{\bf{r}}^2$, you write $E\psi$ next to it, and you must obtain $V\psi$. Are you familiar with the Schrodinger equation?
Comment: Yes, I am familiar with it. Actually I thought along the similar line but then got confused because I thought Hamiltonian has more info than a single state. That's why I am looking for particular "class" of Hamiltonians where this reasoning works.


What kind of workouts I can do in the sea?

Question: I love going to the beach, and I wish I could combine my love for the sea with excercise. What type of movements can I do in the sea so it'd be more like a workout rather than just chilling in water?
Answer: Sorry if this sounds weird, but why not actually go swimming?
Assuming you know how to swim and it is safe there (life guards, weather conditions, cordoned off, etc) then swimming is an amazing workout. It's even more of a workout with some waves and it could cover multiple muscle groups plus improve endurance and breathing. Low impact on the body as well.
The most simple exercise would be breast stroke as you can be relatively stable and have good visibility of what's in front of you. You can make it harder by doing it under water as long as possible to increase resistance and improve endurance and breathing.
If you don't want to go out deep into the sea how about treading water. This will also give you a work out as you work on staying afloat while coordinating legs and arms. To make it more difficult, keep your arms up like you're trying to keep something dry/put hands on your head so you only use the legs. Add on treading while moving to one side of the beach to the other.
Answer: You can jog about 100 yards and back in the low, wet sand to warm up with less resistance and do some but kicks and high knees during the run, also take some time to stretch your calves, hamstrings, quads and glutes. If you are not used to running in the sand it can easy to pull a muscles.And swimming is obiviously one of the exercise.And you can also do spiderman crawls and push ups and also shoulder ups
and you can also do some frog jumps this is not easy to don in sand but this is very helpful because these beach workout challenge your entire body.Working out on beach test your stability,fitness level and mental toughness due to unstable surface.I hope this enough.


Exchange Calendar in Sharepoint

Question: My client have their corporate calendar as an exchange calendar.  How can I setup my SharePoint to view the exchange calendar entries in the SharePoint calendar.  Currently if you connect to exchange it only shows on SharePoint the logged in users' exchange calendar.  I want all the users to see only this one calendar.  How do I set that up?
Answer: You are not able to import your exchange calendar to sharepoint, but you are able to create a new calendar in SharePoint and open it in Outlook by clicking on "calendar" in the ribbon bar of SharePoint (if you are in a SharePoint calendar). Then the SharePoint calendar will open as normal calendar in your Outlook client and you are able to copy your events from your exchange calendar to the SharePoint calendar. Then you will see them in the sharepoint calendar and also users are able to sync it to outlook, if they don't want to open SharePoint.
Comment: So there is no way that you can setup the calendar to invite users from that exchange calendar - the Corporate Calendar. (In other words, that the invite shows that it comes from the 'Corporate Calendar' and responses is shown in the corporate calendar)  Is the only method that you schedule a meeting, you have to do it form your own outlook account, invite attendees and the invite will come from your outlook account and responses will go to your outlook account - one can only copy the event to the exchange (Corporate Calendar)?

Exchange Calendar in Sharepoint


Is there any circumstance in which it is necessary to mark extra payments on a loan as going to "principal and not interest"?

Question: I've heard for years - and not believed - that it was necessary to mark extra payments, clearly targeted towards a particular loan, as "apply to principal" or any other such magic wording in order to get the payment properly applied. Are there circumstances in which this is true? If so, what happens to a misapplied payment?
Comment: Related: [Is asking to pay off principal first a placebo?](https://money.stackexchange.com/q/64580/10997)
Answer: It could be a couple of things besides extra principal:

Future payment. If your payment is $500/month, and you write a check for $2,000 applied to future payments in January, you wouldn't need to make another payment again until May.  This is different than applying to principal, because if you did that, you'd still owe $500 in February, but would be closer to paying off the loan.
Escrow payment. If for some reason you wanted to fund your escrow account (for tax and insurance payments made on your behalf by the lender) more than its current level, you could do this.

I seem to remember hearing that some (shady?) lenders would just pocket extra payments if you didn't specify where they were headed, but I've also been told that this just isn't true.
Comment: 'greedy' as in 'greed is good' might be a better phrase than shady.
Answer: The mortgage I got last year through Wells Fargo explicitly indicates in its terms that excess payment will be considered against future payments (i.e., pay $500 extra in January and you owe $500 less in February) unless you indicate otherwise. It goes on to state that with electronic payments you do not get to specify where excess payment goes, so excess payment made electronically always goes toward future payments. If you want to make excess payments toward principal, you must actually send them a check and your payment stub, with the appropriate box ticked.
This won't be very different for other major banks, I wouldn't imagine.
Comment: This is actually very different from my bank. Countrywide and now Bank of America have three extra boxes in their online payment form: "Additional Principal", "Escrow" and "Other" (other is used for "special fees or late charges").  I think the only way to make a "future payment" (I've done it once accidentally) is to just submit the whole form again.
Comment: That's pretty evil, because it means you don't get any interest on the excess payment.
Comment: I have a very different experience with the US Bank which would randomly assign payments to either future or principle depending on... the weather in Kansas, I want to say? Not sure.
Comment: I've had two mortgages, back in the last century.  The check was mailed with the payment coupon, anything extra in the check simply paid down the principal.
Comment: @littleadv When I had a mortgage with US Bank it appeared that any payment that matched your monthly payment amount would be applied to your next outstanding payment, while any other amount would be applied to principal. It became an issue one year when my escrow amount decreased and was off by a month in adjusting to it. My payment was slightly larger than the monthly payment amount, and that caused it to get applied to principal, causing it to look like I had missed my payment for the month. It took a two-hour phone call to clear it up.
Answer: I had a car loan through GMAC and extra money was applied to future payments.   At one point, I received a statement telling me I had 15 months until my next payment was due because I had not marked extra payments as going to principal.
Answer: I would always presume that given a choice of doing what is in its own self interest verses in the customer's interest, a bank will ALWAYS do the former rather than the latter.
Banks are in the business of making money, always presume that their policies, processes and contractual terms will be slanted to maximize their ability to make money.  It's not being evil or anything, it's just business, they are under no obligation to be altruistic or do what's best for you at the expense of their profits.
So, especially since it's not exactly a hardship, I would always make extra principal payments using a separate check and clearly mark it as an extra principal payment.


First recorded use of a traditional tombstone?

Question: The question is rather straight-forward. I consider a "traditional" tombstone as some sort of monument having an inscribed name and date of birth/death or age.
Comment: @LanceLafontaine: It was the tradition for Pharaohs.  :-)
Comment: It's the date of birth and death that's the clincher here. Ancient monuments/tombstones usually don't have that. Roman tombstones often recorded the age, but not the dates. The practice of recording birth and death on tombstones is certainly not common until the renaissance and possibly even later, but unfortunately I can't find any sources for this.
Comment: @LennartRegebro, An answer considering a monument/tombstone with the age would also be acceptable imo, I've edited the question.

DVK, hmmmmm. I wouldn't say the Pyramids would count, as they certainly aren't "traditional", but no limitation on the status of the individual.
Comment: Certainly these were common (for the well-off) in ancient Rome. I don't know how much further back they date.
Comment: @LanceLafontaine - any limitations such that it must have not been an important personage (e.g. a monarch), or what constitutes a tombstone (do the Pyramids count)?
Answer: Ancient Egypt is thought to be the origination of the funeral tombstone, however the original name was Stele/Stela, and in plural stelae, comes from the latin, to stand.  Stelae have been documented back to the first dynasty - 2890 B.C., they were used later by many number of other cultures.  The highest recorded use is by Attica in Greece, example would be the Greece marble funerary stelae.  The Roman uses of stele came from their expansion into Greece, in which they adopted some of the culture.
Funeral Stele -
Stele - Brooklyn Museum
Heku - Brooklyn Museum
Stele


How to achieve contrast in a black-on-black design

Question: I'm trying to achieve a black-on-black design on a business card. See link here:  AHC 180 Youth Ministry Business Card. The large black arrow and the grunge splotches are a rich black of 40-40-40-100, and the card background is 0-0-0-95. The card is being printed offset and UV coated, probably via an online printer (I'm ordering them through a third party and don't have access to the printer.) It's important that there be enough contrast between the blacks so that the rich black portions are distinguishable, but I still want the background to have a black/almost black appearance. Would I be better to use some version of a rich gray for the background rather than a 95% (or lower) black? I'm open to all suggestions.
Comment: I tried to add the image within the question for you -- odd issues. #1) I would have **never** known there are variations in the dark areas without *reading* what you've typed. I see almost no difference in the image you linked to. #2) If I add your link as an image here, the colors are **really** bad. #3) I download your image, opened in Photoshop and the contrast changes **dramatically**. So, I'm wondering if the image you linked to may be using some odd ICC profile. I realize this doesn't answer your question. But it does make me wonder how accurately the image you linked to is displaying.
Comment: This all may be due to the CMYK color space of your jpg though.
Comment: I noticed it was difficult to distinguish the colors on the jpeg, but it's very clear in the Ai file I created it in, and it was very clear on my inkjet printer. None of which, unfortunately, helps me know how it's going to print on an offset press. :/
Comment: It's very clear when opening the image in Photoshop.
Answer: Don't use a black only at 95%.... make 2 different rich black.
One could be 40-40-40-100 and the other 30-30-30-90.
Personally I recommend you use a bit more Cyan in your recipes rather than making all your CMY values equal: if the printer is not well calibrated (or is digital), a black with more cyan will still look steel black and not dark brown (eg. 40-30-30-100 and 35-25-25-90). You don't need to use a 10% difference, 5% more of cyan is enough.
Usually, if you have a 10-15% difference in your black, it will give a nice soft contrast and will not really look gray. 5% is risky and might not be clearly visible; it could work well though if you were using a spot varnish.
With the 2 rich black recipes I suggested you it should look similar to your example.
Also, when you add a lamination or varnish, it can make the colors little bit darker. Not much, but enough to lose some contrast if you use a 5% difference only between your 2 blacks!
Answer: I would recommend you go with a deep gray instead of 95% black. If your black arrow and splotches are too subtle, they'll look like a mistake rather than a purposeful design decision. A little more contrast will be more visually appealing and more likely to print well.
Another option is to spec out a spot UV coating, rather than having the entire card UV coated. In the case of a spot coat, you'll be able to highlight your design without having different shades of black.
Comment: Spot UV would be great, but it's not an option here. Can you please define for me "deep gray" in CMYK terms?
Answer: Remember that  0-0-0-95 is a halftone of black. So I don't think it's what you'd want. At best, you'd want to use a rich gray and a rich black. What specific rich black and rich gray is hard to say as it could depend on the printer.
Note that subtle black-on-black designs are usually done as clear coats such as UV coating or spot color inks (two separate, but solid colors of black)
As for the sample image, that is so subtle that I don't think you're going to get results you are going to be happy with using only CMYK. However, one thing to try would be to use 100% black and a Rich Black. The rich black will be darker than the 100% black in most cases.


How to build a 3-input NAND gate from 2-input NAND gates or a 3-input NOR gate from 2-input NOR gate?

Question: For NAND, I am doing a truth table for it and then truth tables for all the possible combinations, but as you can see the process is very long and I am still yet to get an answer. Same goes for NOR gate. How do you go about it?
Answer: An alternate approach is given.

simulate this circuit – Schematic created using CircuitLab
The schematic represents the function:
$$Y = \overline{ABC} = \overline{\overline{\overline{AB}} C}$$
Comment: How did you find Step 2 from Step 1?
Comment: @studious \$Y=\mathtt{nand(A,B,C)} = \mathtt{not\{and(A,B,C)\} = \\ not\{and(and(A,B),C)\}=nand\{and(A,B),C\}}\$
Answer: As equations.
\$\overline{ABC} = \overline{(AB)C} = \overline{\overline{\bar A+\bar B}\cdot C}\$
Comment: It's also something that [should have been covered in Boolean Algebra 101](https://en.wikipedia.org/wiki/De_Morgan's_laws).
Comment: Though to build that from NAND/NOR gates would take four gates in total. It can be done with just three gates. Notice that the \$(AB)\$ is a 2-input AND gate, which is equivalent to \$\overline{\overline{AB}}\$ which is a 2-in NAND gate followed by an inverter (another 2-in NAND with both inputs tied together). So \$\overline{ABC} = \overline{\overline{\overline{A \cdot B}}\cdot C}\$
Comment: Wow that's cool
Comment: First week of the semester and so on
Comment: Is there any other way to do this other than this?
Answer: Note that in the above answers, there are three propagation delays for A and B, but only one for C.  Therefore, if propagation delays matter, put two nand gates in series in line C, wired as inverters.


Term for someone with a doctorate in nursing

Question: What would you call someone who had a doctoral degree in nursing? I wouldn't think you'd be able to call them doctor as this would be confusing in the hospital setting. Is there a title used for a nurse with a doctorate degree?
Comment: They are doctors, but not medical doctors. That's why most people's badges in a hospital include one's credentials so you can distinguish, say, an MD surgeon from a PhD researcher from a DNP from a DPharm. Some US states make it illegal (!) for DNPs to use their  rightfully earned title, though, so this answer will have geographic variation.
Comment: This and another recent question http://academia.stackexchange.com/q/59293/16122 make me think about the distinction between "Doctor" as a job title, in medical settings, and as an honorific, for holders of  doctoral degrees in general. It's a distinction that I believe fluent speakers accomodate without ever thinking about.
Comment: I have seen "research nurse" in email signatures. It doesn't imply the PhD degree, but avoids possibility of confusion.
Answer: You call him "Doctor Surname" unless you are sufficiently well-acquainted to call him by his given name.  (I worked with someone with a DScN degree and she was called "Doctor Smith" by the physicians in committee meetings, etc.)
If you and this person will be working with patients, ask "How should I address you when there are patients present?" before the need arises.  As guifa states in the comment above, the badge, or embroidered name, will show the degree, not the honorific.
Edited to add: The scope of practice of licensed healthcare professionals is set by state law, and the doctorate in nursing does not widen that scope in any state that I know about.  Guifa's comment that some states, including my home state, restrict the title "doctor" in the context of health care is correct.  You can expect the holder of a doctorate in nursing to know the restrictions, and to have a preference, so the best way to find out what to do when there are patients around is to ask.
Answer: Dr.
PhDs in psychology go by Dr.; so can PhDs in nursing.
Comment: Please present some evidence that the opinion you give is correct. What you say is plausible but it's also plausible that people would want to avoid confusion between medical doctors and doctors of philosophy in medical contexts.
Comment: @DavidRicherby - Evidence that at least some PhDs in psychology use their title: my son sees a PhD in psychology whom everyone calls Dr.  //  If there is some confusion, it can be cleared up; some medical doctors may look down their noses -- but that would be their problem.  Look, in academia some PhDs choose not to go by "Dr" but that's a personal choice.  Once you have your PhD you have every right to go by "Dr" if you wish to, and in a medical context it would make sense to do so, to make a distinction from the RNs.
Comment: I've also seen PhDs doing research at NIH who were not MDs, but who went by "Dr."


According to the Catholic Church, Does God create each new individual with original sin?

Question: According to the Catholic Catechism, every spiritual soul is directly created by God. At the moment the individual is created by God, does it have original sin? Or is original sin added later?
Comment: Welcome to C.SE.  All your questions are legitimate, and are asked by many people, but for the purposes for this site, you may need to focus on a single concern and phrase it in a way that can be answered objectively by a single authority / theological tradition that you need to specify.
Comment: Sin is passed on by natural generation, a matter of the human nature received from Adam, the first humanity, passed on by parentage (of two parents). The unique individual, with a soul, is a unique creation.
Comment: What's for sure is that 1) God does NOT create a soul with original sin; original sin entered  through no fault of God because we all share a corrupted human nature (see [The Fall](https://en.wikipedia.org/wiki/Fall_of_man)); 2) God offers salvation to everyone, He does NOT send one to hell without the person's input; 3) Why not simply keep them "in Heaven"? Christians answer that this current arrangement is worth it (creation is declared "very good").  God's providence will make things right in the end.  In other words, we are in the middle of an epic drama where we don't see the ending yet.
Answer: You touch on one of the great difficulties that Christians have wrestled with for the entirety of Christian history. I agree with the above comments that your question could benefit from being a little more tightly focused. I will answer the first part about original sin, leaving aside for now the questions about predestination and free will. I have no shame in shying away from those topics or admitting that I'm hesitant/unqualified to deal with them.
From a Reformed perspective (you didn't specify a particular doctrinal tradition so I will answer from the one I know and adhere to), we are under the curse of original sin from the moment of conception. I would point to Psalm 51, where David says that he was "conceived in iniquity", and to Ephesians 2, where Paul refers to us as being "by nature the children of wrath".
When Adam, as the federal head of humanity, sinned, all mankind fell at that moment. (See Romans 5.) Since then, all mankind save Christ has been born in sin, with a corrupted nature inclined toward rebellion against God. This is certainly not an easy thing to grasp, and I do intend to defer on the questions it raises regarding the justice of God because I don't feel I can adequately address matters of such weighty import here. If you are more interested in the Reformed perspective, I might recommend first reading through the book of Romans, in its entirety, at least 2 or 3 times. Subsequently, you might find a Protestant study Bible or commentary on the book of Romans. I could recommend the ESV Study Bible or the Reformation Study Bible, both of which will give you a good but succinct overview of the Reformed teaching on original sin - what it is and why we believe that it makes sense.
For a Roman Catholic perspective, you might check out para. 385-409 of the CCC, and the Confessions of St. Augustine (the latter being a source that Protestants would also readily affirm). However, I'm not Roman Catholic, so another person would be better qualified to inform you on that perspective.
Comment: Is every person created at the same time as Adam? Or is each person created after Adam, in order of their appearance?
Comment: From a temporal perspective I would say that a person comes into being at the time of conception.


Hypnosis in Halacha

Question: Is there a proplem in the Halachic literature with hypnosis? What, if anything, is the issue involved in either hypnotising people or being the subject of such an hypnosis?
Comment: y-oy-y, Welcome to Judaism.SE, and thanks very much for the fascinating question! Please consider registering your account, to help the site keep track of all your contributions, no matter where you log in from.
Comment: What type of hypnosis are you referring to? What is its goal and what methods does it use?
Comment: See Minhat Yitzhak vol. 6 Siman 80.
Comment: http://hebrewbooks.org/pdfpager.aspx?req=1599&st=&pgnum=403
Comment: Related: http://judaism.stackexchange.com/questions/16351/are-you-culpable-for-things-done-under-hypnosis
Answer: The Darkei Tshuva discusses it.
He quotes the Bnei Tzion (Siman 67) who was asked if one was allowed to do a procedure that he called "Magnetization", where one is put to sleep, and in his sleep the person would tell of events occurring far away, and of events occurring privately (in other words, Hypnosis). Being that according to nature it would be strange that such a thing could happen, the questioner wanted to know if this comes from "Kochos Hatumah" or not.
The Bnei Tzion answered that he asked scientists as to their opinion of the nature of Hypnosis. He reported that there were some scientists who said that Hypnosis is a fraud, and all that people see is their imagination. Others tried giving a scientific explanation, but admitted that they don't know how it really works.
In the end, the Bnei Tzion said that it is permitted because it is possible that it has scientific backing, and even though we don't know how it works, we may have just not discovered it yet. Moreover, one is allowed to be cured by a Non-Jew through magic as long as he doesn't use Idolatry, because it could just be a natural cure that we don't know about.
So he ends off that to be cured through Hypnosis is allowed, even if there is no danger. To do it for entertainment could be an issue, though.
Comment: There seems to be a distinction between the "fortune-telling" type of hypnosis mentioned at the beginning, the healing type mentioned at the end and plain old suggestion (not mentioned here?), in which a subject is placed in a semi-conscious state and is more receptive to suggestions of his own or others than he otherwise would be. Does he address that?
Answer: The question also appears in the responsa of Rabbi Moshe Feinstein (Yoreh Deah 3:44 thanks blockhead), asked way back in the 1950s.
He writes that he spoke with someone who knows what hypnotism is; then consulted with Rabbi Yosef Eliyahu Henkin. Neither of them saw it as prohibited; the human mind is a complicated thing, and if using whatever mechanism works to help someone out, fine.
This assumes a person won't get hypnotized to do or believe something against Judaism.
However Rabbi Feinstein viewed the whole thing as somewhat degrading for the human dignity of the subject, so he didn't recommend it just for the fun of it. But if medically indicated (e.g. to quit smoking) or for some other need, it would be fine.
Comment: It's in YD 3:44
Comment: Do you know the language he used so I can search it on responsa.co.il or hebrewbooks.org?
Comment: @blockhead, thanks for the citation and welcome to the site; I hope you stick around and enjoy it.
Answer: From Nefesh HaRav p233
"They asked our rabbi (R' Soloveitchik) if it is permitted for one to
undergo hypnotism not for the sake of healing rather just for fun and
games. Our rabbi answered that this is forbidden. Then they asked what
sort of prohibition is involved in it? And our rabbi answered that is
it "shtus" -- stupid -- and it is forbidden to be involved in shtus."
Comment: R. Yosef Dov Soloveitchik, "The Rav". I'm not sure about the different "types" of psak you mention -- but it is clear from the context that he felt it was osur.
Comment: In which case it might be in keeping with Rambam's view that all sorcery is prohibited by the Torah because it's shtus (rather than, as is the view of other rishonim, that it's indeed effective but goes against Hashem's will).
Comment: Do you know which Rabbi Soloveitchik this was? And do you know whether he meant this as an halachic _p'sak_ or a moral one?
Comment: Since when do we make Peskei Halacha off the idea of "Shtus"?
Comment: @hachamgabriel See Alex's comment above yours.

Hypnosis in Halacha


Please help stock literally screw stuck in wall

Question: Hello I purchased the wall unit and it was free-floating I had to mounted on the wall I don't like the unit so I took it down there was seven screws that went very deep into the wall I took out six of them one is stuck in there I cannot get it out I've used electric drill I've used hammer and pliers I do use needle nose pliers and twist I have been the bar up and back to try to loosen the screw I believe I've done maybe 2 1/2 rotations to the left for it to come off the wall I have to get this screw out of the wall so I could take care of the damage that he already has made I have been the bar which I don't want to do because I'm trying to resell this piece can someone please help me tell me what I should do nothings working. Desperate on the lake DVA
Comment: Punctuation would help if you actually want answers
Comment: How about a picture? Put a link in your question and we can add the pic.
Answer: Get a pair of ViceGrips. Fasten very tightly on the head of the screw and use them to turn the screw out.
Answer: Are you saying you have tried to turn it in and then back out this is what I usually try with tough screws. If going through metal many screws strip out the last thread or 2. If the threads on the screw are stripped I pry up on the screw while trying to back it out. This can be tough but ether the screw will back out or the screw breaks off. Can be frustrating. If all else fails you may be able to rock the screw head back and forth and break it off then shove it in. Option 2 would be to cut the head off and push it in. I have had to do both in the past.then patch the area around the screw.


How important is GRE in Econ Phd Applications?

Question: Does GRE play as a cut-off point in one's Economics Phd application even though s/he has a strong profile including 4.0 GPA, strong recommendation letters, good SOP, and relevant research and teaching experience?
Comment: Every department considers these factors differently.
Comment: Let's say Econ departments in US top 30 schools - Do they really auto-reject your application if the quantitative score is not above 160, without even looking at other factors?
Comment: My image (without evidence) is that economics is *more* likely than other disciplines to use cutoffs for things like GRE scores, GPA, etc. to simplify their jobs and have no qualms with who they might be missing out on, because they see admissions  as a benefit-cost analysis. I could of course be wrong.
Answer: Yes, it does, at a large number of, although certainly not all, top economics departments in the United States. Indeed, they have a lot of applications to read from perfect applicants (at least on paper). Why should they give any exceptions?
But they do give exceptions. I don't know entirely your circumstances, and certainly mathematics isn't economics. But from my own experiences, having 1. written letters for people with bad mathematics subject test GRE scores and 2. being swayed when I've been on committee to admit people with bad mathematics subject test GRE scores, I would encourage at least one of your letter writers to contact someone at each of the schools you applied to to keep a lookout for your application/not throw it out immediately presuming a GRE cutoff, especially if other parts of your application are quite competitive for the schools you are applying/have applied to.
Answer: You can contact the admissions department at the schools you are interested in if their website does not explicitly indicate a cut-off.  A strict cut-off is rare, but does exist.  If you are not getting a straight answer from them, your only option is to just go for it.  There is a lot of unpredictability in PhD admittance decisions.
In my case (social sciences PhD), I had a GRE score that was less strong compared to my GPA, and it was mostly a factor in whether or not I would be offered a scholarship.  At the end of the day, my GPA and recommendation letters were strong enough and I was offered the funding.
Answer: In my experience with economics, it's all over the place.  Some departments do seem to use it as a cutoff, but increasingly more seem to be coming around to using them only at the margins.
This especially holds true if you have good recommendation letters and research and teaching experience; it's difficult to get those things before you start your PhD.  They likely make you stand out well above the crowd.  Heck, it's not unusual for full PhD graduates on the job market to lack teaching experience.
If a GRE quant score is going to be a problem, I anticipate it would matter more at the most highly selective institutions.  Places that only accept a tiny fraction of near-perfect students have few reasons to compromise on any attribute, and GRE scores are an incredibly convenient standardized way to compare everyone.
I've spoken with faculty on admissions committees at both large public research universities and small, selective private universities, and while you can't use my anecdotes as the whole story, the responses I get are invariably that they rely as little as possible on the GRE.