What does it mean to use a normalizing factor to "sum to unity"?

Question: Would you also be able to provide an example? I have very little mathematical/statistical knowledge and have never understood normalization.
Answer: Unity just means 1, so they have presumably normalized their values so that they all sum to 1 instead of whatever their "natural" total is. I could imagine a few specialized normalization schemes, but this is typically done by dividing, and that's what I would assume in the absence of a more detailed description. If they had normalized so that the values summed to 100 instead, they'd be expressing it as a percentage.
Suppose there is a substance made of three chemicals: 5L of Chemical A, 2L of Chemical B, and 3L of Chemical C. You could do a similar normalization and say that each litre of substance contains 0.5L of A, 0.2L of B, and 0.3L of C (each value has been divided by 10, the total, so all the values together sum to one). If you normalized to 100 instead of unity, then you could also say that the substance is 50% A, 20% B, and 30% C.
One of the most common uses of this technique is to turn event counts into probabilities. By definition, probabilities have in [0,1] (i.e., greater than or equal to zero and less than or equal to one). Suppose you have an urn with 10 balls in it, seven of which are red and three of which are blue. You could normalize these counts so that they sum to unity and restate this as the probability that a randomly chosen ball is red, $P(ball=\textrm{red}) = \frac{7}{7+3} = \frac{7}{10} = 0.7$ and $P(ball=\textrm{blue}) = \frac{3}{3+7} = \frac{3}{10}=0.3$.
Answer: A natural application is conditional probabilities. If I roll a die, the unconditional probability of each outcome is ${1 \over 6}.$ But suppose I roll it and tell you that the outcome is at least 4. You can find the new conditional probabilities for rolls of 4, 5, or 6 by dividing ${1 \over 6}$ by ${1 \over 2}$ for each of the outcomes of 4, 5, or 6. This process of division ensures the conditional probabilities sum to unity as they must.


How to block "No Caller ID" calls but not unknown calls

Question: My phone number is published on the website of a project I run. However, it seems some young people have found it really funny to start prank calling me. It's very annoying and rather humiliating to have them get a laugh out of me at my expense. I would like to block them.
The conventional advice is to enable "Silence Unknown callers" in iOS 13. However, this will block not only Unknown Caller ID but also any number not in contacts. This doesn't work for me, because as a part of the project, strangers will contact me by calling which I do want.
Is there any way to only block private numbers/"No Caller ID" in iOS without also blocking people that are not in contacts? It doesn't seem like a hard problem since one can easily tell if it is a number or if it is unknown but I can't figure it out. I've tried the 000-000-0000 trick but it doesn't work.
Answer: I'm fairly certain it's not currently possible in iOS, but your cell carrier may have this option.


What reccent alternatives to LSTM are there for regression problems?

Question: I have been working for a while on a regression problem - predicting the air pollution in a city based on meteorological features (humidity, temperature, wind velocity a.o.). I have trained an LSTM model to do the predictions and it works somehow fine, but I am not impressed - the trend in my predictions is always lagging behind the trend in the ground truth. LSTMs are more than 20 years old so I wondered if there are some new alternatives for regression problems of the kind I am working on? I have read that attention models are popular for text prediction, but are they also suitable for air pollution prediction? What else is there? Especially models that are implemented in TensorFlow and Keras would be of interest for me. Thanks!
Answer: Transformers (aka "attention models") are being used in place of LSTMs in many areas, as they generally give better results, and/or are quicker to train. They can be used for regression problems, just as easily as for classification or text-generation - just create the final layer accordingly.
The catch is they scale as O(N²) in the size of your data. You didn't mention how long the sequences are that you are trying to analyze, but if they are less than 512 items then a transformer should be fine on a single GPU. (And your LSTM is probably doing a poor job with sequences that long anyway.)
There is a lot of active research in making versions of the Transformer that scale to larger values of N. If you read the papers, the claims of O(N) or O(NlogN) are a little misleading as they end up batching things together for efficiency; but still they are managing to work with sequence lengths in the thousands or higher.
For out of the box implementations https://github.com/huggingface/transformers is a good start. For handling larger values of N, I see both Longformer and BigBird mentioned there; the latter was used not just for text but for DNA sequencing. I'm not aware of any research done on meteorological features, specifically, though. (Please leave a comment if you do find anything!)
Comment: Thanks, I am looking now into the transformers! Since you asked - I am using as input sequences of 1 weak of hourly values (7 days *24 hours=168 entries is one sequence long). So do I understand correctly, that the length of the sequences you mention would be in my case 168? I am putting them in batches of 32 or 64. My output are sequences that each are 24 hours long, so sequences of 24 entries. Each of the entries has 10 meteo features (air pollution concentration, temperature, humidity, wind speed...).
Comment: @NeStack When you said a regression problem I imagined you would want a single number output. To get the 24 predictions, just feed your prediction in as the new input, and run the prediction again. (A lot of the Transformer papers will talk about beam search, but you don't need that extra complexity for a physics problem.)
I think "how to turn 10 measurement features into input to a transformer" would be good as a separate question - though I'm guessing you make some kind of embedding already, for use with the LSTM? In which case it should also be usable with a Transformer model.


How to remove a subdivision of a cube

Question: I want to know if there is a way to remove a smaller cube from a larger cube I subdivided. I removed the faces of the corner cube, but this reveals the inside. Is there a way to make the cube not hollow? So I could remove the outside faces and still not be able to see the inside? Thanks
Comment: i think so you can slice the cube with a smaller cube
Answer: Select the seven verts of the corner. Select the lower right vertex last so it becomes the active (white) vertex.

Extrude the selection with EESCAPE. That way the newly created verts stay in their places. Set the pivot point to 'Active Object' and scale the selection to 0 on the Y axis SY0RETURN. This will set all vertices to the y value of the active vertex, putting them in the back. Depending on how your object is oriented, you might need to pick a different axis.

Select everything with AA, remove doubles with WR and recalculate normals with CTRL-N
Comment: Could you explain the second step a bit more? I tried to scale the object to 0 on the Y axis but I believe I'm doing it wrong
Comment: Whenever I try to scale everything on the Y axis to 0, it pulls all the other blocks to it creating slants, instead of creating flat edges like yours shows
Comment: @JoelBanks Sorry, I goofed up and left a step out. Now it should work.
Answer: You could use a Solidify Modifier.
-I added a default cube SHFT + A > Cube.
-Then subdivided it three times W > Subdivide.
-Deleted the three faces in the top corner by selecting them and pressing X > Faces.
-Then added a Solidify Modifier and set the Thickness to .5 and checked the Even Thickness box.
Comment: I tried this and it still looks hollow. Could you go into a but more detail about how you did this? Im very new to blender
Comment: I edited the answer. I hope it's clear.

How to remove a subdivision of a cube


Building a custom login form - encountering issues

Question: I'm building a custom login form and I've tried two methods: wp_authenticate() and wp_signon().
For the former, I am able to correctly return the WP_User object upon a successful authentication, but no cookies are set to signal to is_user_logged_in() that the user is indeed logged in. I suppose I can set my own cookies but is there an easier way?
For the latter, I keep having the error Cannot modify header information - headers already sent by.... I've tried calling the wp_signon() function from the , the actual header, and in the page template. I see the same error regardless. I've looked online but I'm not seeing any solutions to this exact problem.
The specific error is pointing to line 7 of base.php - Warning: Cannot modify header information - headers already sent by (output started at /srv/www/mysite/current/web/wp/wp-content/themes/mysite/base.php:7).
But looking right there, I don't see any issue (these are lines 4 - 10, line 7 is the doctype):
use Roots\Sage\Wrapper;

?>
<!doctype html>
<html <?php language_attributes(); ?>>
  <?php get_template_part('templates/head'); ?>
  <body <?php body_class(); ?>>

As per WP's own troubleshooting, I've checked that there are no extra spaces.
Regardless of how it's gone about, I just need to be able to log a user in with their credentials and have the ability to check their logged-in status to create a logged-in state on a website.
Any help?
Comment: It might be easier to style the existing login form than to build a custom one. That way you don't have to keep up with a bunch of different Core functions, just some CSS.
Answer: Look at the authenticate filter. This will handle everything for you.
function wpse_custom_login($user, $username, $password) {
    if (empty($username)) {
        $errors = new WP_Error();
        //add some error message, return $errors
    }
    $user = get_user_by('email', $username);
    // do some additional validation, checks, etc.
    return $user;
}
add_filter('authenticate', 'wpse_custom_login', 30, 3);

This is a really barebones example but begins to demonstrate how you would log in a user by email address instead of username.


Collisions when adding an address entry to the new table

Question: What does the bitcoin protocol do to handle collisions when adding addresses to the new table?
Comment: What addresses and what new table?
Comment: The addresses that are in the addr message are placed into the new table of bitcoin core.
Comment: Surely addr entries can't collide because there is no expectation that each peer has no peers in common. If two peers report a common addr entry wouldn't you just keep the common value in your table?
Answer: In case of a collision of addrs in the new table, the existing address will normally stay (and nothing changes) - unless

the existing entry is already present somewhere else in the new table (an address can be in up to 8 different buckets/positions at the same time), or
if the existing entry is of bad quality ("terrible")

In these two cases the existing entry will be replaced by the new one.
There are several criteria by which a node can be terrible, roughly:

if its timestamp is too far in the future or too far in the past from the current time.
if we unsuccessfully tried to connect to it too often in the past

See Addrman::IsTerrible() for details / exact limits.
It may also be worth to mention that the behavior in case of collisions in the tried table is very different from this ("test before evict").


Why does the Metropolis algorithm allow changes even for ∆E > 0?

Question: In the Metropolis Monte Carlo algorithm, why can you accept changes even for $\Delta E > 0$ (provided that a random number is less than a given probability ratio, e.g. $\exp(-\beta \Delta E)$)?
Comment: Basically: you want the global minimum and if you don't allow going up in the energy landscape, you can't get out of a local minimum to get to the global one.
Comment: @Phonon Sorry, I didn't know that was the etiquette around here. Thanks for letting me know. I have since accepted one of the answers.
Comment: user2561523, it would be nice if you accepted one of these guys' answer, they have all provided you clear and sufficient explanation! I've noticed you very rarely accept answers to your posts, it is not a nice attitude on SE to just take your answer and not show appreciation!
Answer: Standard Monte Carlo samples the canonical (NVT) ensemble. So it maintains constant temperature but the potential energy is free to fluctuate - both up and down.
This will only seem odd if you incorrectly imagine the equilibrium state of a system to correspond to that with the minimum energy. The equilibrium state is actually determined by the minimum free energy which balances potential energy with entropy. So although there will be a natural inclination to decrease the potential energy, there is also an inclination to increase entropy (which the $\Delta E>0$ case helps achieve).
As a demonstration, imagine starting with an ice structure and increasing the temperature to 1000 K. What will happen to the structure if you omit the $\Delta E > 0$ case? Absolutely nothing.
Comment: Dear lemon, since you are also very much involved with computational physics in your studies, I was wondering if you had any recommendations for introductory books on MC and MD simulations, in physics. Other than the famous Daan Frenkel & Berend Smit book. Thanks in advance!
Comment: @Phonon Frenkel & Smit is a favourite of mine but a slightly softer introduction is Allen & Tildesley's  classic *Computer Simulation of Liquids*. Otherwise, most MD/MC software come with very detailed manuals - I've learnt a great deal from these.
Comment: By the way, interestingly about the lowest energy vs the lowest free energy point you bring up in your answer, it is also a matter of confusion to a lot of people when it comes to liquid-liquid phase coexistence interfaces, where although the lowest energy would correspond to a planar interface, at equilibrium the interface is actually fluctuating due to a greater entropy (low knowledge on the interface's actual position), which I find very neat! That's why I liked your answer right off :)
Comment: @Phonon That's absolutely right. It actually took me a long time to fully get my head around the role of entropy in chemical systems but, once I had that 'aha!' moment, *so* many things suddenly made perfect sense. It is possibly the most important thing I've ever learnt.
Answer: The underlying reason is purely mathematical (apart from the fact that the relative probability of a state is $\exp(-\beta E)$), so'll give a mathematical answer.
The idea is that you want to sample the state space, meaning that you want to randomly generate states so that the generated states follow a probability distribution, in your case the Boltzmann distribution. One way is to directly generate samples, but that is often not a realistic option. An alternative is to randomly walk through the state space in small steps, where the steps are generated to follow a certain distribution in such a way that the long term sample will follow the required probability distribution. The Metropolis algorithm is one of the simplest such schemes, in which neighbouring states are randomly generated and accepted or rejected in such a way as to fulfill the previously mentioned condition.
The answer to your question is simply that if you would reject changes with $\Delta E > 0$, then you wouldn't be sampling according to that distribution.
If you want I can elaborate on how you can see this.
Answer: It's because you don't want to just find an optimum, but to sample the entire distribution. The MH algorithm satisfies a property called "detailed balance", and for me this video is the most intuitive explanation I've seen.
Comment: Not allowing "backwards" motion also makes it possible that you *can't* find the optimum if your starting conditions are in a part of the phase space dominated by a local but suboptimal extremum.


What sources of data/parameters should I use when Unit testing?

Question: I am performing unit tests across a large system, made up of hundreds of different .java files, all forming the back-end.
In my unit tests, should I pass the variables as they are from the other methods (calling the methods within my test method) or do I test using values that are created/declared in the test method?
I'm thinking that I should come up with values specifically for the test method since these are unit tests and I am trying to test each method in isolation, but I'm not certain about this.  Do I need to copy the functions exactly that fetch said data into the unit tests?
Answer: Generally speaking, you should create the values in the test itself, thus better isolating the system under test.  There are other kinds of tests, as @James mentions, and you can use junit for integration tests as well as unit tests.  But at the heart of junit testing is unit testing, and proper unit tests isolate the system under test.
Update in response to your comment:
So for example if you have classes A and B:
public class A {
  private B b = new B();

  public void callB() {
    b.process(17);
    b.process(22);
  }
}

public class B {
  public void process(int n) {
    // do stuff with n
  }
}

Your test class for B could simply instantiate its own B and call b.process(17) and b.process(22) without any reference to A, nor need to subclass A.  In order to test A in isolation from B you would need some kind of mocking mechanism which would replace B with a mock.  Such a test would only use the mock to verify that b.process had been called with 17 and 22, not worrying about what happened as a consequence of those calls.
Comment: Thanks.  That clears things up for me.  But to expand on this question, how exactly do you override the method that normally passes to the method being tested with the test method?
Comment: Thanks again.  Very concise but explanatory answer.
Answer: The answer is, again, it depends. :)
It depends on what you are trying to test. If you are trying to unit-test a function whose arguments might be returned from other functions or external inputs, then in my opinion, you should manufacture the test arguments in your tests, so that you can test all kinds of scenarios and corner cases.
If you are trying to test the INTEGRATION between a function and other functions or inputs, you are sort of doing an integration test. Then, you'll have to wire the different functions together and execute your test cases with upstream inputs.


Want get rotation based on the details of four corners of a square

Question: I got four corner points of the object which are
topLeft, topRight, BottomRight, BottomLeft
and are as clockwise.
I want a rotation values in X, Y and Z for unity object to rotate based on the rotation of these four points.
Actually, these points are coming from python and I want to represent rotation of it on unity object which has Rotation x,y and z
Comment: These corner points are expressed in 3D space, or are they 2D points in screen space (or calculated with respect to a camera view)? Are the corners known exactly, or is there some error/jitter we need to smooth out?
Comment: This: https://gamedev.stackexchange.com/a/138035/10408 ?
Comment: this is some insanely advanced algebra, I tried writing an answer but I've given up as it was taking hours. you can detect the movement but you need to understand a ton of advanced functions. Theres surely a better way. Why do you need to do this, it seems utterly useless?
Comment: @DMGregory These three points are coming from realsense using stereoCamera and it is accurate as I have checked it by myself. it is in x y and z. these points are coming based on stereoScopic camera
Comment: @Pow Exactly, Well, I found a way to actually do it. I chose to take those coordinates and pass it to Unity Script using Socket and then calculate there.

p.s. this is more easier way to do it. as Python is not pretty complicated for 3d stuff in my opinion.
Comment: I too, also found an equation to do it, but it was very complicated
Answer: If the object is a square, you can do this:
// Find perpendicular vectors running sideways...
Vector3 right = TopRight + BottomRight - TopLeft - BottomLeft;

//...and vertically along the object's edges.
Vector3 up = TopLeft + TopRight - BottomLeft - BottomRight;

// Use a little vector math to get the remaining
// perpendicular axis, forming a basis.
Vector3 forward = Vector3.Cross(right, up);

// Extract the orientation of that coordinate basis.
Quaternion rotation = Quaternion.LookRotation(forward, up);

Then you can use the quaternion directly (good if you need to interpolate/blend the rotation) or extract rotation.eulerAngles if you need the output as angles (just note these are not as nicely behaved and can have unintuitive and large value discontinuities for small orientation differences, even though they still express the same orientation as the source quaternion)


Compilation error: CS0246 in an ASP.net MVC3 project

Question: I'm trying to follow this tutorial word for word. MVC Music Store
I'm already on part 9 however, when I try to press the button "Checkout" it shows this error message:

Compiler Error Message: CS0246: The type or namespace name 'Mvc3ToolsUpdateWeb_Default' could not be found.
public class _Page_Views_Account_LogOn_cshtml : System.Web.Mvc.WebViewPage

I was thinking that, maybe I had added or deleted something, like a "usings" reference line, if that helps. So what I did was:

I tried to clean, build, rebuild the project and the solution.
Deleted temporary log files - restarted the computer.
I researched on the internet for similar errors such as this, but I didn't see anything. I also checked the comments on the tutorial however I didn't see any errors similar to mine.

The links I searched were:
My google search
Stackoverflow search
Kindly enlighten me on what to do. Thank youuuu!
Answer: As far as I can see from the screendump you provided, this has to do with authorization. in the addressbar you can see the Controller action you are trying to reach(redirect URL)
Check if your account controller is valid
Link to account controller


Keep getting small punctures on spoke side of tube

Question: I am using 27.5 x 2.1-2.4-inch tubes in tubeless rims on a hard tail trail bike. Mostly riding trails. I keep getting small punctures on the spoke side of the tube. Could be the same spot but it's hard to map. I thought spokes were sealed on tubeless rims so they shouldn't be able to penetrate the tape/seal. Thought it might be that I'm inflating to 60 psi but never was a problem for years, just now. Can't conceive how it could be anything but a spoke but...
Answer: You got the next step nailed already.  Use an "offset" from the valve to figure out exactly where on the rim is the cause.
Then feel around that area for a sharp point or a sharp corner of some sort.  If you have spoke-nipple access holes then the corner can be burred, or it might be some irregularity at a butt-joint.
Once you find anything sharp, file it smooth with a needle file or a de-burring tool, or accurate sanding with sandpaper.
If you find no cause, look for any kind of edge.   Hard rim tape can even cause punctures through abrasion.  Small pebbles or bark or similar debris can do the same.

One "workaround" for you is to try going tubeless, and store the tube in your bag for an emergency.
Comment: Agree with this.  If you're set up for tubeless, I encourage you to go tubeless. For $6--less than the cost of a quality tube--you'd have enough sealant till next year and very little risk of flats, especially the silly, irksome ones like you're experiencing.  The lower pressures of a tubeless set up only add a positive in terms of increased comfort and grip on trails without a great deal additional rolling resistance.  No tube would actually improve things in that sense.
Comment: You'll be amazed at the greatly improved ride quality and grip on the trail if you went tubeless and had 25-30 psi or less in the tires. If they're 2.3" wide or more, even lower pressures are advised for max comfort and traction.  You should have rims with an internal width of at least 25mm to run wide tires with pressures under 20-25psi.  You could still go tubeless with narrower rims
Comment: @jeff Tubeless is an option that avoids the underlying cause, its not a perfect solution and has its own drawbacks.   The rim might not be air-tight and the tyres might not be tubeless-compatible.   Personally,  I prefer tubes, was only mentioning as a possibility.
Comment: My own tubeless experience is less than 5 years old, and I'm the type to resist change--gimme a loose ball Shimano hub with a quarter turn of a cone nut window to hit for a perfect preload any day--however, the advantages of tubeless I allude to in my comments above are so dramatic to the ride quality that if it seems like the pieces are in place to go tubeless, that's what I must advise. While the OP doesn't specifically mention tubeless ready tires, they do state the rims are (arguably the more important factor for tubeless set up  and tubeless was a thing prior to "tubeless ready" gear).
Answer: The tube could abrade on any sort of irregularity, even something that got loose inside. The first things you should do are: map the location - this should not be hard if you are patching or at least keeping the damaged tubes - and remove the tire and tube and carefully inspect the rim interior and the tire interior. Something stuck low in the sideway could be causing the problem and looking as if it were spoke side.


Measurement of water

Question: I've been making chicken soup for decades, but today I'm in a little bind. I have two large enough chicken thighs with bone in. How much water and broth should I use?
Comment: I'm unclear.  If you have been making soup for decades, what has changed to make this an issue for you?
Answer: While I agree that the question is unclear, there is perhaps a clear answer to this from either of the directions that I can see.

If you are intending on making the thighs into stock -, add your other ingredients (veges, herbs etc), if any and cover with water.

If making soup from these and adding stock + water to cook the thighs so that they are eaten as part of the dish as a whole - then again, cover them with liquid. How much of each component you use is up to you, but I would suggest all liquid stock for this scenario. If you have a more concentrated stock, then dilute to taste with water.

Measurement of water


Twitter Feed is auto refreshing

Question: This has been happening for a while and I'm finally trying to fix it. Whenever I open my twitter application, it always auto refreshes the timeline feed. If I haven't checked it in a while, it automatically goes to the top of my feed. I've tried clearing the data, uninstalling, even switching phones. Does anyone know whats going on? If not, are there other suggestions for twitter clients?
Comment: I believe this is the default behaviour.
Answer: This is what twitter is supposed to do, it's not a bug, however if you want to try some other twitter clients here are some (Paid and Free)
Talon for Twitter - Paid
Carbon for Twitter - Free
Plume for Twitter - Free
Comment: Correct and +1 but I just want to add that apps like Carbon are only allowed 100,000 tokens for Twitter and tend to fill up quick as people don't know to drop the token if they aren't using the app anymore so you may have that issue with some apps.
Comment: @RossC It's pretty annoying, I wish twitter would loosen up a bit, they can still insert sponsored tweets into your feed so I don't know why they aren't more supportive towards 3rd party clients

Twitter Feed is auto refreshing


What are the best practices for Nationalized SEO?

Question: I am working on Internet marketing for one of the Website designing & development company in India which is located in Mumbai. So the website is performing quite well in local search places or up to state level in SERPs. But not with all major locations in my country, so my question is what are the best ways I have to stay on top of the SERPs.
Comment: What is a SERP? A kind of web-service or search engine?
Comment: SERP means "Search engine results pages" I want to say. So can suggest the right solution?
Comment: I don't know if there is a solution (I highly doubt). A search engine like does differentiate it's results by many parameters. For example, when searching for the same search query, two people will almost never see the same search results, as they personalized. The same accounts for regions and other things, that could be used as filter.
Answer: Rajesh, if you are looking to outrank others in SERPs in Google, then you will need to have physical presences in other metros. Add those addresses to your Google Local (they will even send you a card via snail mail to that address for address verification).
Once you have verified your address for all the major metros, you need to start pushing your fans for reviews across all these locations.
You might even wan't to get listed in the location specific services (although I cannot really vouch for any other service except Just Dial).
Comment: Thanks for you effort Prasad, but these not the whole picture behind. Yes physical location is one of the ranking factor which can help you to boost your website rank in that particular region, but it's even more bigger. Like if you search for "Online shopping" from you place you will get homeshoop18.com on the top and even if you tried with other locations it stays constant. so that dos't mean it's having physical location at all around. What you think?
Comment: hmm, I see what you mean. So you do not want to get higher rankings for particular locations, but instead want to get a high ranking across all locations (independent of the location).

Did you try looking at the linking of homeshop18.com (more than 2500+ sites linking to the site).


filter fields of type date with the view module filters

Question: I have a field in my database of type: timestamp in this format: yyyy-mm-dd hh:mm:ss , with the view module I would like to filter this field so for example I want to select an interval: dispaly only date from x to y. I taked a look in the view module code and there is a date filter that handel data of type date or time in this format, but when I tired to create a new view with view module and set up this kind of filter I didnt found it in the exposed filter list, the availble filters works only with int or string type: like is equal to, starts with...so how to get the time filter from the view module user interface.
Comment: Do you have the Date module installed? https://drupal.org/project/date
Comment: yes but I still dont have the date filter in my view module interface
Answer: You need to enable the Date Views module (part of the Date project) to be able to filter using interval operators such as "Is between":

Take a look at the upvoted answer to this question for details: How do I add a date field that can be filtered by a relative value?
Comment: yes Thank you I have already tried this: the use of the date module and I have obtained those filters in my view module interface but the problem once I apply one filter for example filter date between date1 and date 2 I obtain nothing as a result!
Comment: yes just after publishing the question I tried to use the Date module


Right ascension - Gaia vs Simbad

Question: What is the difference between Right ascension in Simbad and Gaia Archive, please? How to convert the values? For instance, HD 37468: 05h 38m 42.0s vs 84.68652242854718 deg. Should not be these values nearly the same? How to convert in astropy, please?
Answer: 1 hour = 15 degrees.  60 min = 1 hour and 60×60=3600 sec = 1hour.
So to convert: (5 + 38/60 + 42.0/3600)*15 = 84.675
There is a small discrepancy, which is due to the fact that your quoted value is the simbad location of the sigma ori cluster, and not the bright central star, which is at  05 38 44.76538 according to simbad and identical to the Gaia value, as calculated below.
Reverse the process:
84.68652242854718 / 15 = 5.6457681619
0.6457681619 * 60 = 38.746089714
0.746089714 * 60 = 44.76538284
so 84.68652242854718 = 05h 38m 44.8s
Comment: Actually the descrepacy is probably due to the fact that sigma ori is not a point star, but a tight cluster with multiple sources very close to each other.  Simbad gives the ra of the main star as 05 38 44.76538  and the ra of the cluster as 05 38 44.0
Comment: I never understood the advantage of using hh:mm:ss instead of degrees. Do astronomers really find hh:mm:ss more convenient?
Comment: @EricDuminil Some of them apparently (still) do. I do not. I guess in the days of computer processing it is just a relic of the past, much like using sexagesimal angles DDD°mm'ss" instead of plain decimal degrees.
Comment: Thank you so much.
Comment: I have vague recollections of having to do time based math to use the setting circles on an old telescope in a class I took about 20 years ago.

Right ascension - Gaia vs Simbad


Ethereum Internal transactions how to work with it?

Question: I've covered a bunch of forums and I do not understand what Internal Transactions is in etherscan. I have been transferred to the transaction and it is in Internal Transactions. And I do not see her in my balance. How do I bring them to the main wallet, if possible.
Answer: Internal transactions aren't actual transactions on the blockchain and therefore aren't included directly in the blockchain. Internal transactions are value transfers initiated by a contract or when a contract simply makes a call to another contract. The result of the value transfer or contract call isn't stored on the blockchain and therefore you cannot return the result of the internal transaction from the blockchain.
Etherscan obtains the results of these transactions by running a modified node that records all the value transfers by looking at the actual transaction that resulted in the change, and then stores the effects of the transaction separately as an 'internal transaction'. Currently there is not any way to imitate this process simply using the web3 API.
These related questions provide more information:
Normal transactions VS. Internal transactions in etherscan
How to get contract internal transactions
Comment: So it is possible to move ether from one account to another without it ever being registered on the blockchain?


Do all normalized quaternions represent valid rotations?

Question: Basically, I'm getting a bug where the rotations in the animations seem to be skewing the model even though I'm normalizing them. I suspect that the rotations are showing the error, but not causing it, if that makes sense.  But that's based on the idea that a normalized quaternion can't skew a model.
Answer: Yes. There are two equivalent normalized quaternions for every orientation in 3D space (the unit quaternions form a double cover over the space of orientations), and every unit quaternion can be expressed as an angle-axis rotation.
If you're observing skewing, then it's not from your quaternions themselves, but could be due to non-uniform scales at parent levels of your hierarchy, or a math error somewhere. We'll need to see more of your implementation to advise, though.
Consider asking a question "How do I solve this unwanted skew in my skeletal animation?" instead.
Comment: Thank you! I suspect that the some of the data produced by the exporter has a floating point rounding error, which would explain why it doesn't happen with sample animation files made by khronos group; so mostly i just needed to narrow down where the error might be.
Comment: We give floating point a hard time, but used correctly, a single-precision float should have a relative error of only 2^-24 (or less than one part in ten million). This amount of error in an animation keyframe should not be perceptible. You might have an accumulation error somewhere that allows tiny errors to snowball frame over frame or through repeated calculations though. Updating a matrix from a previous matrix each frame is one common way to get this kind of drift if you don't correct dor it.
Comment: @DMGregory How do you correct for that drift?
Comment: [See my answer here](https://gamedev.stackexchange.com/a/114284/39518).


Keycloak Support for JWE & Opaque for Access Token and Refresh Token

Question: I would like to know whether Keycloak supports JWE or Opaque Tokens for access or refresh token. Documentation suggests that jwe is supported for id token but not sure for access and refresh.
Answer: Opaque tokens are not supported in current versions of Keycloak.
Access and refresh issue was closed with resolution Won't do.
However, there is a PoC project available in Github (albeit for older versions) by Thomas Darimont, the maintainer of the Keycloak.


Showing an estimator is consistent

Question: Show that $Y_1$, the first order statistic is a consistent estimator of the parameter $\alpha $ of a uniform distribution with $\beta = \alpha+1$
 Here $f_{Y(1)}(y_1)=
\begin{cases}
n*[1-(y_{(1)}-\alpha)]^{n-1},  & {\alpha <Y_{(1)}< \beta} \\
0, & \text{otherwise}  \\
\end{cases}$
By definition If  $P[|Y_{(1)}-\alpha|<\epsilon]$ approaches 1 as n goes to infinity for all $\epsilon >0$ then $Y_1 $is a consistent estimator for $\alpha. $
Thus,
$P[|Y_{(1)}-\alpha|<\epsilon]$=$P[\alpha - \epsilon< Y_{(1)}<\alpha +\epsilon]$.
My question is with the limits of integration.
What is the lower and upper limits of $\int n*[1-(y_{(1)}-\alpha)]^{n-1} dy_{(1)}$ be? should it be from $\alpha$ to $\alpha + \epsilon$ Or from $\alpha $ to $\beta$.
I think it should be from because this should work for any value of  $\epsilon $ and if I put limit as  $\alpha$ to $\alpha + \epsilon$  then this would violate $\beta = \alpha+1$  for a particular $\epsilon$.
Please tell me what the limits should be to show that this is a consistent estimator
Comment: How exactly do you define probabilities "$P$" in terms of integrals in the first place?  Giving some thought to that might reveal the answer to you.
Comment: Sorry I don't understand what you mean
Answer: You must take into consideration the fact that you are examining a distribution with a closed interval as support. This means that
$$\alpha \le Y_{(1)} \le \beta = \alpha +1 \Rightarrow 0\le Y_{(1)} -\alpha  \le 1$$
so you already now that $\sup|Y_{(1)}-\alpha| = 1$ and so for $\epsilon >1 $ the condition required for consistency holds.
So you need only to prove
$$\lim_{n\rightarrow \infty}P[|Y_{(1)}-\alpha|<\epsilon] =1\,\qquad 0<\epsilon \le 1 $$
Furthermore, since $0\le Y_{(1)} -\alpha  \le 1$ we have that
$$P[|Y_{(1)}-\alpha|<\epsilon]= P[Y_{(1)}-\alpha<\epsilon] = P[Y_{(1)}<\alpha +\epsilon]$$
Then use the cumulative distribution function to express this probability in the usual way (no $\epsilon$ under consideration here will send you out of the support) and consider the limit as $n\rightarrow \infty$, for $0<\epsilon \le 1$.
Comment: Thanks for the great explanation .In a similar way I was able to show that $Y_{(n)}$ is also a consistent estimator for $\beta$.There $\alpha - \beta <= Y_{(n)}-\beta<=0$ and thus $0<=|Y_{(n)}-\beta|<=1$.Thus $sup |Y_{(n)}-\beta|=1$.And for $0<\epsilon<1 $ case $P[|Y_{(n)}-\beta|<\epsilon]$ since  $Y_{(n)}-\beta$<=0 this probability becomes $P[-(Y_{(n)}-\beta)<\epsilon]$

Showing an estimator is consistent


How can I enable WinHTTP trace logging in Server 2012 R2 for viewing raw HTTP commands and application details?

Question: I have an application running on a Windows Server 2012 R2 system and the app leverages winHTTP for various network requests.  It's not able to communicate with another server on the network and I suspect (but can't confirm) that there's a network issue.
All of the troubleshooting commands/tools that I'm familiar with leverage WinINET so I don't have an easy mechanism for verifying connectivity.  As such, I'd like to increase available logging.
Back in Server 2008, I could run something like:
netsh winhttp set tracing trace-file-prefix="C:\Temp\dpws" level=verbose format=ansi state=enabled max-trace-file-size=1073741824

I got that from this microsoft article.
When I try running the same command on Server 2012, I get an error (or perhaps information statement?):

I tried following the instructions and tried running netsh trace start scenario=InternetClient but the resulting ETL file didn't look quite right (perhaps just newbie error on my side).  When I reviewed the etl in network monitor 3.4, I saw what looks like system calls:

...but I'm not necessarily interested in that -- I want to see the information occurring at the network connection and HTTP levels.  Is there an easy way to see that?
Mr. Google also pointed me to this article but none of the event viewer messages seemed to help or capture the type of information I'm looking for.
Help?
Answer: Had similar problem as yours, this guide was helpful, i atleast now see stuff in it but not in the most helpful format. The short summary is

Update the parser profile to use windows parsers
Filter to HTTP

https://blogs.msdn.microsoft.com/jpsanders/2009/08/24/using-netsh-to-analyze-wininet-problems-in-windows-7-and-windows-8/


Euler's theorem on homogeneous functions proof question

Question: Euler's theorem for homogenic functions states, that an $f:\mathbb{R}^n\to\mathbb{R}$, continuously differentiable function is homogeneous of degree $k$ if and only if for all $r \in \mathbb{R}^n$ the following equation satisfies.
$$\sum_{i=1}^nr_i\partial_if(r)=kf(r)$$
A proof my professor did was fine for the part where we start from the fact that $f$ is homogeneous, so then the equation is satisfied. The other part is where I have problems, when we start from the fact that the upper equation is true.
He did the following:
Define $g:\mathbb{R}\to\mathbb{R}$ to be $g(t) = \frac{f(tr)}{t^k}$ where $t>0$. By the theorem's criterions we know that $g$ is differentiable (since $f$ is continuously differentiable). Taking the derivative of $g$ we get:
$$g'(t) = \frac{\sum_{i=1}^nr_i\partial_if(tr)t^k-kt^{k-1}f(tr)}{t^{2k}} = \frac{\sum_{i=1}^n(tr_i)\partial_if(tr)-kf(tr)}{t^{k+1}} = 0$$
By the criterion, this is zero, and this is where we finished, the theorem is proven. It's not clear how does this finish the proof. Didn't we simlply proved, that $g$ is a constant function, so $f(tr) = ct$ for some $c\in\mathbb{R}$? How can the original statment be deducted from this, that $f$ is homogeneous, by definition, the $f(tr) = t^kf(r)$ equation holds?
Edit: What I thought first is that we can maybe define $g$ to be $g(t) = \frac{f(tr)}{t^kf(r)}$. But then we have no criterion so that $f(r) \neq0$, so it seems incorrect. But even by doing this I'd still have the problem with it simply being a constant function, hence not being able to get rid of the $c$ constant. It seems like I can't notice something.
Comment: The constant is $g(1)=f(r)$. Therefore $f(tr)/t^k=f(r)$.
Comment: Ohh, since $g$ is constant and we know $g(1)$ to be $f(r)$, then $g(t) = f(r)$ for every $t$. I think I understand now.
Answer: Thanks Jens Schwaiger for the tip in the comments, the credit is his, I'm just going to post it as an answer.
By showing that $g$ is a constant function, we can plug in any $t > 0$ value to $g$ and that will give us the constant. Plugging in $1$ we get that $g(1) = f(r)$, hence $g(t) = f(r)$ for every $t>0$.
$$\frac{f(tr)}{t^k}=f(r)$$
Reordering this we get the desired result, which is:
$$f(tr) = t^kf(r)$$


Can I paint the background of my gas fireplace?

Question: I want to paint the background of my gas fireplace (behind the logs) a lighter color so the logs and fire will be more visible.  Do you know of a paint I can use to do this?
Answer: Yes.  These are painted all the time.  I just used this for a traditional wood burning fireplace.  You can search for fireplace paint but really you are looking for it to withstand the max temperature.  Since yours is gas I am guessing your max is well less than 1000 F.
Also most fireboxes are painted black so you can see the fire easier.  And because of the heat a lighter color may get burn marks in it from the heat.
Comment: +1 for black.  A lighter color will only show soot better (even natural gas produces some soot), and won't actually make the fire/logs more visible.
Comment: @Nick2253 - Exactly.  All of the designers want a pretty color to sell a house.  I have seen a lot of orange lately... Which will turn to dirty orange, then brown, then brown with soot/burn marks...  Then we will get questions on how to clean paint in firebox.


Conditionally format a range based on the value of a single cell outside of it

Question: I am using conditional formatting with a custom formula. I want to highlight rows in the range A2:B11 if the values in $B2 (column B starting at row 2) is greater than the value in the cell D5.
I can get it to work if I "hardcode" the value (which I presently happen to know to be 326), by using the formula =$B2>326; but if the value changes, I don't want to have to update the formula. How can I refer to the value in cell D5? I tried =$B2>D5, but that doesn't work (and I don't know why).
Answer: Use the conditional formula =$B2>$D$5.


How do I check if certain pages have been indexed?

Question: What's the Google search to see how many pages are indexed within the search engine?
Answer: If you don't own the website, Google's site: operator can give you some rough info. It's not that accurate, though.
If you do own the website, use Google Search Console to check the Index Coverage report. This should give you an accurate count of the number of pages that are indexed.
Answer: If you want to check a certain page and not get a count of how many pages are indexed, you can search for a phrase from the page.

Choose a 6 to 10 word phrase from that page
Put it in quotes
Search for it in Google

For example if I search for a phrase you used:

"Google search to see how many pages are indexed"

As of now, Google shows no results for that phrase, indicating that this page is not indexed.

If you have a list of pages from your site and you want to see how many of them are indexed, you can create a sitemap of them.

Create a sitemap containing only the URLs you want to know about.
Add the sitemap to Google search console.
Wait until Google reports stats for that sitemap.  It is usually within a week, but I've seen reports recently of it taking months in some cases.
Google will tell you how many of the pages in the sitemap are indexed and give you an index coverage report for just the pages in the sitemap.


Dictionaries in Python

Question: What do these two statements mean in Python?
distances[(clust[i].id,clust[j].id)]=distance(clust[i].vec,clust[j].vec)

d=distances[(clust[i].id,clust[j].id)]

I am guessing that the first statement assigns clust[i].id and clust[j].id keys of the distances map to the result of the distance(..) function. However, I am confused since lists are represented using [] and dictionaries using {} in Python. What's the correct answer?
Comment: "However, I am confused since lists are represented using [ ] and dictionaries using { } in Python.".  What?  The `[]` is for getting an item, not representing a list.  What makes you think it has anything to do with lists?
Comment: Also note that `anything[(a, b)]` can be written as `anything[a, b]`, just like you can do `for x, y in z:` and `for x in y, z:` without needing the parentheses.
Comment: @S. Lott. Is this your way of helping people who have less factual knowledge about a particular programming language than you?
Answer: Dictionary literals use {}. Indexing operations use [], regardless of type.
Answer: distances[(clust[i].id,clust[j].id)]=distance(clust[i].vec,clust[j].vec)

distances is a dictionary where keys are tuples of probably integers and the value is the distance measured between them by the distance function.
in the second line:
d=distances[(clust[i].id,clust[j].id)]

the d variable is just assigned to that distance, accessing the dictionary value just assigned.
other answers provide the summary of what's a dictionary.
Answer: Hopefully this will make it clear:
>>> a = {}
>>> a[1] = 2
>>> a[(1, 2)] = 3
>>> a
{(1, 2): 3, 1: 2}

Dictionaries in Python


When to use subscript and when to make it a function?

Question: Let's say, I have a set of cats $C = \{ a, b, c, ... \}$. Each cat has a tail. I can say, that the lengths of the tails of cats are denoted as $t_a$, $t_b$, etc. Otherwise, I can say that they are denoted as $t(a)$, $t(b)$, etc. Which option is preferable and when?
Comment: I'd say whatever is more convenient for you.
Comment: In the case of discrete, non-numeric data, subscripts are fine. The functional notation would be appropriate in discourse explicitly related to set theory, IMO. But the nuance is thin.
Answer: Both are valid, and the choice is based on personal preference and taste.  One benefit of the notation $t(a),\dots$ is that it allows you to refer to the function $t$ that maps from $C$ to lengths, which may be useful in some contexts.  One benefit of the notation $t_a,\dots$ is that if $C$ is finite and small, in some settings it might be intuitive to think of $t_a,t_b,\dots$ as separate variables (though of course the two are still equivalent).


Data - Changes Audit Trail

Question: What are typical scenarios where the user might require a data-change-audit-trail?
Answer: There are many requirements for capturing changed data. I list only three common ones below.

Audits (HIPAA, SAS70, etc.)...one may need to audit SQL Server logins as well as attribute data changes to specific users
EDI...some insurance carriers require one to send to them current and previous data when a policy is altered, say, due to a life event. One may need to send one's previous coverage together with the new coverage. This is a good candidate for using SQL Server Change Data Capture (CDC).
ETL for DWs...require data change capture in order to add new data to facts and dimensions as well as process updates to slowly changing dimensions. Usually, something like SQL Server's Change Tracking would be right for this, since it is a "lighter" tool than CDC.
Answer: You may also want to create an audit trail if you need to be able to selectively fix bad data changes.
For instance, suppose I have imports of the sales roster for the client. One time they accidentally remove a name and our process assumes she doesn't work there anymore and removes her access.  But she does still work there and in order to immediately correct the problem (I can't just run the previous roster as that would remove the new employees), I can find the data that was changed through the audit log and restore her. Or if someone maliciously changes data or runs a bad table update query (I saw someone update the entire  table once because he forgot a where condition, the audit tables saved his job), it is easy to get it back.
I have never worked on an Enterprise system that didn't use and need auditing. This data is critical to the success of the business and the ability to fix it quickly when things go wrong is priceless.

Data - Changes Audit Trail


Problem while maximizing Google Chrome in Xubuntu 20.04

Question: I'm using Xubuntu 20.04. When I am trying to maximize google chrome, the maximize button, minimize button and the close button get above the visible screen area.
Answer: This is not a fix for the problem, but here's what I've done on my one workstation to remove the title bar from above Chrome 95 when it's maximized in XFCE.

In Chrome, enable the Use system title bar and borders option.
In the XFCE Window Manager Tweaks, enable the Hide title of windows when maximized.
In apps that have optional CSD, enable it. In an app like VS Code you would change the Window: Title Bar Style setting to custom.
Learn to live with the fact that some apps (MySQL Workbench, Thunderbird, etc.) now don't have min/max/close buttons in the window title bar anymore when they're maximized. Personally, I can do that all with the keyboard shortcuts so I don't mind too much.

My main takeaways:

I appreciate the extra vertical space that this setup gives me in other apps.
It helps me towards using the keyboard for all window management.
If I happen to be holding the mouse and I want to do things, I can always use a windows taskbar item to min/max/close it.

Before I tried the little experiment above, I did some research to find out what is actually going on with Chrome. Here is what happened: They switched off their custom X11 window management code in favor of using a library called Ozone which handles all the window management features for them.
Here are all the links I collected reading about this:

https://bbs.archlinux.org/viewtopic.php?pid=1990969
https://bbs.archlinux.org/viewtopic.php?id=244031&p=22
https://twitter.com/maksim_sisov/status/1431272534356471964
https://piunikaweb.com/2021/09/23/google-chrome-94-use-system-title-bar-and-borders-checkbox-broken/
https://support.google.com/chrome/thread/127138612/use-system-title-bar-and-borders-broken-in-google-chrome-94-please-repair?hl=en&msgid=127842587
https://www.phoronix.com/forums/forum/software/desktop-linux/1275863-chrome-chromium-s-ozone-x11-code-now-fully-enabled-old-legacy-x11-code-to-be-removed/page4
https://old.reddit.com/r/kde/comments/pgm1n9/chrome_title_bar/
https://bbs.archlinux.org/viewtopic.php?pid=1990969
https://forum.manjaro.org/t/howto-enable-hardware-video-acceleration-video-decode-in-google-chrome-brave-vivaldi-and-opera-browsers/51895/23
Answer: Try to right click on top bar of Chome (where tabs are located), in a free area and then select Use system title bar and borders.
Comment: This is a workaround, but we used to be able to run Chrome without the option of using system title bar and borders. I think we will have to wait until the Chrome team fixes this bug.
Comment: It seemed strange to me because I was playing with my appearence settings and I wasn't sure what did I do wrong. But I realized that what I told you to do wasn't the fix, but a rather a workaround with the incovenience of the window manager bar above the browser.
Answer: It looks like this problem is fixed in Chrome 96.0.4664.45, even when Use system title bar and borders is disabled.
I'm on Manjaro, XFCE 4.16.
Comment: After further testing, the window maximizes correctly when using the maximize button on the window decoration, but it still hides a little under the system bar when using the `Win-↑` shortcut.
Answer: Same thing happened to me, right after I updated Google Chrome on Xubuntu 20.04. I downloaded the previous version from October 7th, 94.0.4606.81-1, and downgraded. On this version, the issue goes away. It's the same story for Chrome Beta and Unstable, the latest version causes some funky fullscreen behavior on Xubuntu.
Here's the deb for the previous version of Chrome:
https://dl.google.com/linux/chrome/deb/pool/main/g/google-chrome-stable/google-chrome-stable_94.0.4606.81-1_amd64.deb
Answer: If you are using fedora, this might help:
wget https://dl.google.com/linux/chrome/rpm/stable/x86_64/google-chrome-stable-94.0.4606.71-1.x86_64.rpm
Comment: Welcome to the site, and thank you for your contribution. Please note that [brevity is acceptable, but fuller explanations are better](https://unix.stackexchange.com/help/how-to-answer). You may want to add a note _why_ you think this approach will solve the OPs problem.


What are the most severe possible sentences faced by the three accused Russian spies?

Question: Three Bulgarian National alleged Russian spies have been arrested and charged in the UK. What is their worst possible outcome on the other end of this?
Comment: Relevant [BBC article](https://www.google.co.uk/amp/s/www.bbc.com/news/uk-66504350.amp)
Answer: My understanding is that the investigation in to alleged spying is on going and yet to be concluded, and they have only been charged with a section 4 Identity Documents Act 2010 offence: Possession of false identity documents etc with improper intention.
The maximum sentence is at s.4(4):

(4)A person guilty of an offence under this section is liable, on conviction on indictment, to imprisonment for a term not exceeding 10 years or a fine (or both).

If they are ultimately charged with assisting a foreign intelligence service under the Official Secrets Act, the maximum penalty is 14 years.
There's also the possibility of being deported at the end of (and occasionally instead of, or completing in their home country) any sentence under section 3(5), Immigration Act 1971:

(5)A person who is not a British citizen is liable to deportation from the United Kingdom if—

(a)the Secretary of State deems his deportation to be conducive to the public good; or

(b)another person to whose family he belongs is or has been ordered to be deported.

[(3)(5)(b) might, for example, be applicable if only one of the married couple was convicted]
What the potential sentence is, if any, for alleged spying will only be known if/when charges are brought.
Comment: @NateEldredge That addition was made by someone else (who probably should've know better) and TBH I ignored it; so good spot. I answered according to the known facts, deliberately avoiding the allegations of spying until further, accurate information is available.
Comment: Your second link describes the National Security Act 2023 which only came into effect this July, while the defendants were arrested back in February.
Comment: As to the National Security Act 2023 (if it applied), you may have overlooked Section 1, "Obtaining or disclosing protected information", which is punishable by life imprisonment.  Previous legislation probably had a similar provision.


If a car breaks down in the drive thru lane of a fast food place, would the driver be liable for lost business?

Question: If a car breaks down in the drive thru lane of a fast food place, would the driver be liable for lost business while waiting for a tow truck?
Comment: Is there a reason you can't push it in neutral gear?
Answer: I know from experience, that when my car broke down at one, the manager sent the cooks out to help me push it out of the way.
Answer: Liability in the sense that you're referring to would have to arise from some wrongful act on the driver's part, so the driver would have to have been negligent in some way. The first step is to establish that the driver had a duty to care about a forseeably damaging situation; then, did he knowingly put the restaurant at risk? The law does not hold you blanketly responsible if someone suffers a loss because of you, but it may hold you responsibly if the loss arises from you doing something that you should not have done. If you refuse to let them push your car out of the way (assuming no compelling justification), they would probably be on the hook, whereas if you were unable to push your car out of the way and they were unwilling, you probably would not be. There is no generic "duty to not drive a vehicle that might break down". At a certain point in the analysis (pretty much here), we would need more details of the event and jurisdiction, since the law varies by state in the US, though foreseeability is a sine qua non as far as I know.


How to successfully delete a Facebook message that you sent someone from their inbox remotely

Question: I sent a message to someone that I didn't mean to, although they haven't seen it yet. It was very personal and I don't want them to read it. Is this possible to accomplish?
Answer: You can't delete message from someone else inbox, it has seen or not that doesn't matter.
Answer: There is no way of deleting your message from your friend's Chat Inbox or from a Conversation once it is sent. Messages will only be deleted from your Chat Inbox or Conversation.
The official article from Facebook Help Center:

How do I delete messages or a conversation?
You can delete messages one at a time, or you can delete an entire conversation.
[...]
Note: Once you choose to delete a conversation, this can't be undone.
Keep in mind that deleting a message or conversation from your inbox
  won't delete it from your friend's inbox. It isn't possible to delete
  sent or received messages from a friend's inbox.


Google showing site links only for USA

Question: Google is showing my websites' sitelinks only to the USA (I can only see the sitelinks via VPN) i already added my country on google search console international targeting. how can i fix this?
Comment: There isn't a lot you can do to control sitelinks.  See [What are the most important things I need to do to encourage Google Sitelinks?](https://webmasters.stackexchange.com/questions/503/what-are-the-most-important-things-i-need-to-do-to-encourage-google-sitelinks)   I doubt that you will get an answer that is different from those posted there, but I'll leave this question open (not duplicate) because the other question doesn't mention anything about them only appearing in certain countries.
Comment: but why is it showing in USA?
Answer: Unfortunately, as Stephen mentioned above, there isn't that much you can do to make Google display sitelinks in organic search results. Per Google's own documentation, "We only show sitelinks for results when we think they'll be useful to the user. If the structure of your site doesn't allow our algorithms to find good sitelinks, or we don't think that the sitelinks for your site are relevant for the user's query, we won't show them."
Basically, if Google shows sitelinks in the US but not elsewhere, it means Google deems your deep site content to be more useful for searchers in the US. There are a few things you can do, in addition to what was already mentioned in Stephen's link to a previous response, but again, this doesn't guarantee anything; it might improve the chances.

Analyze the search trends from different countries. You can use Google Search Console, Google Analytics (or whatever analytics program you have installed), and any other service you may be using (like Moz or Ahrefs) to look at search queries that bring users to your site, broken down by region. Then examine their behavior on the website, their site search queries, etc. Look for differences in US vs other country trends, and pivot your content strategy based on that.
Have you implemented hreflang meta tags? If not, and your website is available in different languages and regional variations, you may wish to do this. Here's the Yoast guide; see if this applies to you, and if you have it implemented properly.
Do you have structured data properly implemented on your website? It can help search engines understand what the website is about. If the data is in English, for example, but you have different language versions (per #2 above), you may consider structured data that matches the language of the website.

Again, these are general good practices and they may work, but there's still no guarantee.

Google showing site links only for USA


Vcenter Virtual Appliance External SSO Server Setup

Question: I have recently downloaded Vcenter 5.1 virtual appliance and deployed it as a virtual host on a ESXi host. Currently I am using the embedded SSO for user authentication and authorization, but as we already have an existing setup of LDAP server with samba PDC, is there some way to integrate VCenter appliance with the existing system ? In Vcenter configuration, external SSO requires an external lookup service URL with username and password. Any thoughts on possible solutions please ??
Answer: Add a vCenter Single Sign On Identity Source


What are the validations I need to perform before transferring data from source system to target system and if my source system doesn't any have data?

Question: What are the validations I need to perform

Before transferring data from source system to target system?
If my source system doesn't have data to transfer to DWH, how do I test in that scenario?
Answer: Q. Before transferring data from source system to target system?
Before transferring data from source system to target system, why there is a need to validation ?
 So to answer it, the prime focus of validation here that the data which is going to be loaded into target system must be accurate, complete without data loss. So based on that data in the target system different solution and alternatives can be taken as business decision for growth.

-Verify Data Uniformity i.e. there must be exact match of the entities actual values wherever used. For ex. it might be within same schema or across schema (i.e. Consider BookId from Books table and BookId from Readers table must be exact matching within source system or across target system).

-Find out Data Entity presence / absence / present with different name throughout source system and target system as per design model.
-Verify Data is logically accurate, finding issues in quality not only from source system but also from target system by execution of test on target system and rechecking with the source system for defects.
e.g. verify the accuracy on Non-numerical content (for ex. Emails / Pin codes / Phone) and domain based analysis (for ex. Gender[M/F], Age range[1-18,18-30, above 50], reference files any) on stored data.
-Verify the data model design is as per business requirement for that firstly we need to look out for metadata defined for the target system and then move on to tables and fields level definitions for their accuracy. To be precise, we need to cross check Data Type, Data Length, Index and Metadata check across environments.
-Sometimes there are some change taken in source system in the mid-way when the project is in progress and did not get implemented in target systems. Identify such change and take it into consideration in either next phase or stop and re-run based on the priority.
-Verify one must validate Data Integrity constraints like Foreign Key, Primary Key reference, Unique, Default, etc.
-Verify Data Completeness which can be done with help of record count (i.e. matching count of records) and column data profiling (i.e. filtering unique values, picking up minimum, maximum, average values, filtering out null values on important columns) by comparing source and target system.
-Verify transformation logic on data of source system by preparing and executing some test on source data and identifying the mistakes comparing with expected values ahead from actual execution.
-Verify uniqueness of data by identifying the unique values in column based on data model prepared. Verify by running test if they are unique in the system and then next move on to identify actual duplicates if exists.
-Verify for Mandatory fields from source system and also must have default values associated with field.
-Verify that you document tests that you are working with data from specific time period. For e.g. There might be an instance where every bi-weekly there is a discount change logic on different products and you may end up with wrong values. Consider in your planning such instances.
-Firstly filter out NULL data columns and validate if null is allowed and secondly, if found important we should make sure that they cannot be null in future as it might be important for making business decision.
-Also it is extremely important to consider Range check on columns specifically for e.g. consider For Life Insurance policy Age must not cross 60 / Purchase quantity must not exceed above 2000 as per business requirement.
-Document if any business requirements to be met i.e. From date must be greater than to date, Age criteria for Driving license, Left date must be null on Active Employees, etc.
-Please ensure about the Aggregate functions used are purely documented with examples and verify the calculated values stored in target system must give same aggregate values based on calculations.
-Verify data truncation and rounding logic concern with business needs.
-Verify encoding values from the source system should be rightly populated into target system.

Considering above points before transferring data from source system to target system will really helpful in successful data transfer and optimum data in Target system.
Q. If my source system doesn't have data to transfer to DWH, how do I test in that scenario?
In such case, we can do it in 2 ways,

We can contact to actual concern Database Architecture person who have knowledge related to tables and entity relationship between them.

Else you need to understand the entity relationship and database architect of the source system and create / add data by your own.


AWS SES with Google Apps MX Record Record Delete Necessary?

Question: I don't have much knowledge, so before proceeding on something too fast, I'd like some help on AWS and Gsuite MX records.
I have a domain example.com, which is registered on Godaddy, but i have its DNS set up to use it with Route53, since Im hosting the site on AWS and using a variety of their services, such as SES which the bulk email service for my website's transactional email such as notifications.
Previously did not have it set up with a mail server like Gsuite or anything, since no emailing was being done with the example.com domain. The only Email work being done is Amazon AWS's SES service at the moment. I know want to be able to send and receive emails with same domain name, and also keep SES running with my website normally.
I added example.com to Google Apps domains, and already verified by adding CNAME records through Route53's DNS management tool. Google's Gsuite needs me to add MX record to the domain on the DNS tool.
The issue is the following:
I already have MX records created on route 53 for smtp bulk emailing with this MX record: 10 inbound-smtp.us-west-2.amazonaws.com
Google's G suite's instructions say I have to delete all present MX records to be able to add their MX records. If I delete this MX record, it will disable my SES service from Amazon.
Question:
Can I add google's MX records and leave the current one supporting SES as well into route 53, without affecting each other and both services work fine? (Gsuite + SES related MX records together?
Answer: If you are only using SES for outbound, then delete the SES MX record and use the Google records.  MX only affects inbound mail.
You can't use both on the exact same domain name because the MX records dictate where all mail addressed to any user at the domain name is to route.  The routing cannot be more granular than that.
In the future, if you need inbound SES, you can create a subdomain and use that for your inbound addresses, with a new MX for the subdomain pointing to SES.


Is it possible for individual faces to have separate materials from the rest of a mesh?

Question: I've only got maybe a week's worth of total experience with Blender and I figured it would be fun to attempt something that isn't overly complex, i.e. something cube-like, so I decided to recreate the Companion Cube from Portal 1.    In modeling and figuring out the center circle pieces I noticed something I missed earlier though. See how to the top of the center circle the pink actually continues into the base of the circle?

I thought I could use loop cuts aligned with the cut out parts of the cube core

which I would then separate from the rest of the mesh in order to have separate materials but I learned that with a subdivision surface modifier involved the results are not that great.

Is there a way for only the two faces resulting from loop cutting to have the pink material and also not go wacky or am I going about this in a way that won't work?
Thanks in advance for any and all help, assistance, and advice given and shared.
Answer: You can assign multiple materials to the same mesh, and then in edit mode select faces and in the material tab assign those faces to whichever material you want.


Can I have Data Exported into Shared device automatically

Question: I have a requirement where I should be able to export users on weekly basis and keep them in shared Device. By going through the salesforce docs it says that we can able to schedule data export but can we keep them in shared device along with this scheduled Export?. Any help please
Answer: You can use native data export to export the data in the system. But when this process complete it send zip file to you on email which you need to manually download.
As per docs.

Salesforce creates a zip archive of CSV files and emails the user who
  scheduled the export when it's ready. The email address for this
  notification can't be changed. Exports complete as soon as possible,
  however we can't guarantee the date and time of completion. Large
  exports are broken up into multiple files. To download the zip file,
  follow the link in the email or click Data Export. Zip files are
  deleted 48 hours after the email is sent.

Export Backup Data from Salesforce
We also have one more option here. You can use Data loader CLI to schedule to export data from Salesforce and store that in you local system. This way you don't need to worry about download files from email in a time frame. This complete process will be automate and run in background.
You can find more details here: Automate Salesforce Data Import/Export Using Data Loader CLI


Fails to create publishing site collection in scripted web application

Question: I have a problem on my SharePoint 2013 farm. I have a script to create web applications in my farm, but when I do I cant create publishing site collections within that web application. (Originally posted here: https://sharepoint.stackexchange.com/questions/64308/fails-to-create-publishing-site-collection-in-scripted-web-application
So, the environment is setup like this:

We are using host headers for the applications.
We have BackConnectionHostNames set up in registry.
For now we use the Farm admin account to run the app pool.
We have mysites setup and apparently working.
No search is setup.
We have a content type hub setup and apparently working.

So, the symptoms are appearing to me like this:

I cannot create publishing site collections in my new host header based web application when I created it from my script. When I go through the GUI to create the publishing site collection it says "working on it" for a while, then presents me with an error while still spinning the "working on it". In the event log there is this to read:
<code>Event log message was: 'The site template was not provisioned successfully. Delete this
site collection in Central Administration, and then create a new site collection.'.
Exception was: 'Microsoft.SharePoint.SPException: Provisioning did not succeed. Details:
Failed to initialize some site properties for Web at Url: ''
OriginalException: Access is denied. (Exception from HRESULT: 0x80070005
(E_ACCESSDENIED)) ---> System.UnauthorizedAccessException: Access is denied. (Exception
from HRESULT: 0x80070005 (E_ACCESSDENIED))
</code>
If I created the web application from Central Admin GUI I can successfully create a Publishing Portal in it.
If I created the web application with my script I can create a team site successfully.

Below follows my script, can anyone see something that's apparently wrong with this? Did I forget something that the CA GUI takes care of?
<code>$ver = $host | select version
if ($ver.Version.Major -gt 1)  {$Host.Runspace.ThreadOptions = "ReuseThread"}
Add-PsSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
Import-Module WebAdministration -ErrorAction SilentlyContinue

Function CreateWebApplication($WebApplicationURL, $HttpPort, $WebApplicationName,
                              $ContentDatabase, $ApplicationPoolDisplayName,
                              $ApplicationPoolIdentity, $ApplicationPoolPassword,
                              $PortalSuperReader, $PortalSuperUser) {

Write-Progress -Activity "Creating Web Application" -Status "Creating Web Application $WebapplicationURL"

if($WebApplicationURL.StartsWith("http://"))
{
    $HostHeader = $WebApplicationURL.Substring(7)
    $HTTPPort = "80"
}
elseif($WebApplicationURL.StartsWith("https://"))
{
    $HostHeader = $WebApplicationURL.Substring(8)
    $HTTPPort = "443"
}

$AppPoolManagedAccount = Get-SPManagedAccount $ApplicationPoolIdentity

$AuthenticationProvider = New-SPAuthenticationProvider –UseWindowsIntegratedAuthentication
#Create a new web application using the existing parameters, assign it to the WebApp variable such that object cache user accounts can be configured
$WebApp = New-SPWebApplication -ApplicationPool $ApplicationPoolDisplayName -ApplicationPoolAccount $AppPoolManagedAccount.Username -AuthenticationProvider $AuthenticationProvider -Name $WebApplicationName -url $WebApplicationURL -port $HTTPPort -DatabaseName $ContentDatabase -HostHeader $HostHeader

Write-Progress -Activity "Creating Web Application" -Status "Configuring Object Cache Accounts"

#Assign Object Cache Accounts
$WebApp.Properties["portalsuperuseraccount"] = $PortalSuperUser
$WebApp.Properties["portalsuperreaderaccount"] = $PortalSuperReader

Write-Progress -Activity "Creating Web Application" -Status "Creating Object Cache User Policies for Web Application"

#Create a New Policy for the Super User
$SuperUserPolicy = $WebApp.Policies.Add($PortalSuperUser, "Portal Super User Account")
#Assign Full Control To the Super User

$SuperUserPolicy.PolicyRoleBindings.Add(
    $WebApp.PolicyRoles.GetSpecialRole(
    [Microsoft.SharePoint.Administration.SPPolicyRoleType]::FullControl))

#Create a New Policy for the Super Reader
$SuperReaderPolicy = $WebApp.Policies.Add($PortalSuperReader, "Portal Super Reader Account")
#ASsign Full Read to the Super Reader
$SuperReaderPolicy.PolicyRoleBindings.Add(
$WebApp.PolicyRoles.GetSpecialRole(
[Microsoft.SharePoint.Administration.SPPolicyRoleType]::FullRead))

Write-Progress -Activity "Creating Web Application" -Status "Updating Web Application Properties"

#Commit changes to the web application
$WebApp.update()

}

CreateWebApplication "http://add.ress.lan" 80 "Intranet 3"
"sp_intranet3_content" "Intranet3 Pool" "sp_farm" "P4sswd!"
"sp_superreader" "sp_superuser"
</code>
Answer: Try running from SharePoint Management Shell as Administrator. My script is very similar.  Ensure SuperUser and SuperReader accounts exist in AD.
In the error, the URL is blank.
Your script is to create a Classic Mode Web App, not a Claims-based Web App.


How to use your PC as a display for your Xbox One S

Question: My TV is broken and I still want to play on my Xbox. I tried using an HDMI cable to connect my Xbox to my PC but my PC wouldn't display anything. How do I connect my Xbox to my PC using an HDMI cable?
Answer: You need a HDMI input port on your PC and configure your PC to simply use pass though the signal. I highly doubt there is one, it's most likely a HDMI output port. So you can't do it. If your monitor supports HDMI, you could try that instead (for the PS4, it won't recognize PC monitors unless the monitor supports TV input).
Comment: `for the PS4, it won't recognize PC monitors unless the monitor supports TV input` how can I tell if my monitors support TV input? Shouldn't every monitor with a HDMI input work for PS4?
Comment: @XtremeBaumer I haven't had a problem with recent monitors, but early (and cheap) ones I tried didn't properly process a TV signal. I imagine that as long as it can support a 720p or 1080p resolution you should be fine.
Answer: I know this answer doesn't specifically involve connecting an Xbox One to a PC with an HDMI cable as requested in the original question, but the overall objective of using a PC for sound and video while playing on an Xbox One can be achieved with Game Streaming via the Xbox App running on the PC.
For full details of how to setup Game Streaming see this Microsoft support page.
Answer: It's very rare for PC's to have any input for HDMI. If you have a monitor that you use for your PC and it has a HDMI port, you can plug it in there and change the input to HDMI, although the monitor may not have sound.
Another way is to start your Xbox (Hopefully you have auto sign in selected), and then start Xbox Companion App on the PC (you need Windows 10). Sign into your Xbox account on the Xbox Companion App, you can then stream your Xbox to the PC which has both Video and Sound streamed across.


What are unknowns in linear systems?

Question: I am studying linear algebra right now and my textbook says something about unknowns in linear systems. The number of linear equations is represented by the variable "m" and the unknowns are represented by the variable "n". I have tried researching what unknowns are in the internet but could not find any answer to my question. As a result, what are unknowns? Are they the coefficient's of each variable in each equation? Thanks
Answer: The unknowns are just the variables. E.g. if I have the system $$x+y=1, \quad x-2y=7, \quad 3x+4y=12$$ that's a system of three equations in two unknowns ($x$ and $y$). So in this case $m=3$ and $n=2$.

Note that this terminology makes good sense if we're trying to solve a system of equations: the idea is that each variable represents some value that is fixed, but which we don't know yet - that is, an unknown!

What are unknowns in linear systems?


Is there an ability to use common list across multiple team sites?

Question: I am very new to SharePoint and looking for a way to create a list or library in one team site and then reference that list from another team site. In research thus far I have come across descriptions of ways of achieving this using site collections. However, this appears to go against the modern UI and 'flat world' approach to SharePoint. It would also be preferable to have a solution that is easy to implement for individual users, rather than requiring a site admin.
Comment: In  SharePoint, when we talk about client side code the rest API's are executed in respect to the current site's context. So in that case we don't have to hard-code the names of list. This is helpful while moving solutions from development site to production site,
Answer: A common request that might be similar to yours is to create a central repository of Document Templates, Manuals and so forth in one Site Collection and then reuse that repository in each "Customer Case"/Project/Team Site , each of them a new Site Collection.
This is very often implemented using search. The search result source is defied on the tenant level and therefor readily available on the new sites.
That said, IFAIK Modern UI doesn't have a Search Results web part yet so you have to use a classic page on the site to display any search related stuff :-(


Comparison of 2 multimeters

Question: Can I ask a question about which one of two multimeters would be better to buy or it will be closed? I don't want a comparison between a lot of them as it would be opinion-based but just between 2 of them.
Comment: Adam, you would be better off if you take this question to our excellent [EE.SE chat](http://chat.stackexchange.com/rooms/15/electrical-engineering), at least for pre-screening.  I appreciate that you asked here before posting to the main board.
Comment: @NickAlexeev I am a long time user of the Stack sites so I know how things work :P I have never used the chat thought, so I don't really know how :P
Comment: [EE.SE Chat](http://chat.stackexchange.com/rooms/15/electrical-engineering)
Answer: Could be okay, but be specific about what you are asking. For example, are there certain specs that you don't know how to interpret? Do you have a specific kind of project in mind that might require a specialized DMM?
If you just ask "which one is better?", the answer will be "Read the specs for each and see which one meets your need for a lower price".
Even if you ask, "how often will I need a capacitance measurement function?" that's an opinion or anecdote based question and the answer depends entirely what kind of project you work on.
Comment: Thanks I will try to make it a good one although no matter what people will always find an excuse to downvote in here... :P

Comparison of 2 multimeters


Normed space.. inner product space

Question: Every inner product space is normed space but the converse is not true,  what is the condition we must have to make the converse true?
Comment: It must satisfy the parallelogram law.
Answer: Let $(X,\|\cdot\|)$ be a normed vector space. Then, $\|\cdot\|$ arises from an inner product if, and only if, it satisfies the parallelogram law:
$$\|x+y\|^2 + \|x - y\|^2 = 2(\|x\|^2 + \|y\|^2)$$
for all $x,y \in X$.
Answer: The norm must satisfy the parallelogram identity, i.e., you must have $||x+y|| ^2 + || x-y||^2 = 2 ( ||x||^2 + ||y||^2)$.
Look at the post here Norms Induced by Inner Products and the Parallelogram Law for a proof. (The complex case is done similarly)

Normed space.. inner product space


Propositional logic: Why is there values in "$\lor$" and "$\neg$"?

Question: I'm having some difficulties in understanding why there are values under the symbol $\lor$ and $\neg$ in the truth table. Could someone explain me why and/or how you give a value to a symbol or is there something I'm misunderstanding?

Thanks alot!
Answer: I'll be analyzing the second line.
On the third column you should first read the connectives whose scope is the smallest and progress to the connectives with larger scopes.
The 'first level' of these scopes is the second negation in the statement $\neg (P\lor\color{red}{\neg}Q)\lor Q$. This negation affects only the first $Q$ and nothing more.
The 'second level' of these scopes is the first disjunction which affects only the first $P$ and $\neg Q$.
The 'third level' is the first negation which affects only $P\lor \neg Q$.
Finally the 'fourth level' is the second disjunction which affects $\neg(P\lor \neg Q)$ and the second $Q$.
Having established this, I proceed with analyzing the second line.
In the second line $P$'s truth value is $1$ and $Q$'s is $0$.
Now what happens on the first level scope connectives? Since $Q$ is $0$, then $\neg Q$ is $1$, thus a $0$ appears right below all $Q$'s in the statement and a $1$ appears below the second $\neg$ in the second line.
Since $P$ is $1$, a $1$ appears below every $P$ in the statement. The second level is the first disjunction, in which the first $P$ in being disjuncted with $\neg Q$.Since $P$ is $1$, a $1$ appears below $\lor$.
The third level is the negation and it will be flipping the truth value of the disjunction of the truth value just mentioned above, hence a $0$ appears right below the first $\neg$.
In the fourth level, there's a disjunction between the first $\neg$ (and all its scope) which is evaluated as $0$ and the last $P$ which is $1$. Therefore a $1$ appears below the last disjunction.
For a more detailed explanation regarding the concept of 'scope' you can check the section Ambiguity and parentheses on the book Language, Proof and Logic.You can find that section on page 79 of the book (89 of the PDF).
Answer: I think that you have the light gray being the values of $P$ and $Q$ repeated.
The values (black) under the second $\neg$ are the values for $\neg Q$. And the valued under the first $\lor$ are the values for $P\lor \neg Q$. So the values under the first $\neg$ are the values for the statement $\neg(P\lor \neg Q)$ and the final $\lor$ are the values for the whole statement.
I would make the table like this:
$$
\begin{array}{cc|c|c|c|c|}
        P&Q&\neg Q & P\lor \neg Q & \neg(P\lor \neg Q) & \neg(P\lor \neg Q) \lor P\\
        0 & 0 & 1& 1& ...& ...\\
        0 & 1 & 0& 0& ...& ...\\
        1 & 0 & 1& 1& ...& ...\\
        1 & 1 & 0& 1& ...& ...
      \end{array}
$$
You can probably fill in the rest.
Comment: is there any other way to set up this formula in a truth table so it becomes easier to read? I get confused by setting up truth table like this. Would appreciate if you could give an example.
Comment: There's lots of worked examples in standard textbooks, like the one I mention in my answer (which I'm told that students find particularly clear).
Answer: Truth tables of complicated expressions are sometimes written by making separate columns for each of the separate operations that occur in the expression. So, for your expression, we may first make a column that tabulates the values of $P\lor \neg Q$, then make a separate column for $\neg(P\lor \neg Q)$, then another for $P$ and then a final column for $\neg(P\lor\neg Q)\lor P$. This makes it easy for evaluating the final expression for different values of $P$ and $Q$.
However, a more compact method demonstrated in your table is the following:
Under each variable that occur in your expression ($P,\,Q$), we write their respective values that they take on in their respective columns. Then, if a variable is negated, we write the negated values under the said variable's negation sign. Then the values of expressions like $P\land Q$ or $P\lor \neg Q$, etc. are evaluated and are written below the $\lor$ or $\land$ sign. We repeat this until we have evaluated the final expression.
In your case, the final values are written under the $\lor$ sign connecting $\neg(P\lor\neg Q)$ and $P$.
Answer: A basic assumption of propositional logic goes something like that all of the connectives qualify as truth-functional, which in more conventional mathematical terms might get more specifically stated as that all connectives qualify as truth-operational.  This means that if we assign truth variables to any variables, there will exist some value V(a, ..., z) where V indicates a function of propositions.  For your example we have two truth-operations $\lor$ such that
$\lor$(0, 0)=0, and
$\lor$(0, 1)=$\lor$(1, 0)=$\lor$(1, 1)=1.
$\lnot$(0)=1, $\lnot$(1)=0.
You give a value to a symbol $\lor$ or $\lnot$ by using those functions or something similar.
By no means do you have to set-up truth tables in infix notation.  In infix notation the principle connective jumps all over the place, in the sense that it's position varies from well-formed formula to well-formed formula.  You can set up truth tables by writing all binary operations (those like $\lor$ and $\land$ which qualify as truth-operations of two truth values) after their arguments.  Or you could set up truth tables by writing all binary operations before their arguments.  With your example you could write:
<code>  p  q  ¬  ∨ ¬   p ∨
  1  1  0  1  0  1  1
  1  0  1  1  0  1  1
  0  1  0  0  1  0  1
  0  0  1  1  0  0  0
</code>
Or
<code>  p|  q| q ¬| p q ¬ ∨| p q ¬ ∨ ¬| p q ¬ ∨ ¬   p ∨
  1|  1|   0|        1|          0|                1
  1|  0|   1|        1|          0|                1
  0|  1|   0|        0|          1|                1
  0|  0|   1|        1|          0|                0
</code>
Answer: The convention in play is that in the main part of the table (after recording the truth-values of atoms -- if we bother to that again, since that's just copying across the values assigned at the beginning of the line) we write the truth-value under the main connective of the (sub)formula we are evaluating at that step. So it is indeed wffs that are being evaluated -- we just place the resulting valuation under the connective whose impact is relevant at that point in the overall calculation.
You'll find a clear explanation of this convention in most textbooks.
But I'd perhaps particularly recommend looking at Ch. 9, and especially at §9.7 (called "Short working") of P*t*r Sm*th's An Introduction to Formal Logic (CUP).
Well, I would, wouldn't I ...!


In 2 Corinthians 7:3 what does Paul mean by "you are in our hearts to die together and to live together"?

Question:
NASB 2 Corinthians 7:3 I do not speak to condemn you, for I have said before that you are in our hearts to die together and to live together.

It sounds kind of romantic and tragic. What does he mean and was it specific to these Corinthians?
Answer: Paul was contrasting his ministry to them compared to false teachers who were on the "taking" side, not willing to die for them, really not living with them spiritually.  They were the wolves in sheep's clothing, while Paul and company were willing to give their everything for the Church at Corinth (and all others).
Editing to meet requirements: My initial support for any opinion of a given interpretation of scripture (in this case English-KJV) is context before and after, then seeking companion scripture(s) with similar context.
2 Cor 6- 7:2 lays the framework for 7:3.  It declares the high price Paul pays to deliver truth to that area heavily influenced by idolatry and many false religious doctrines, a nest of deceivers. 2 Corinthians 6:8-9 (KJV)
"8  By honour and dishonour, by evil report and good report: as deceivers, and yet true;
9  As unknown, and yet well known; as dying, and, behold, we live; as chastened, and not killed;" is to me a fair summary of that chapter. 2 Cor 3 is a strong background for his plea not to become corrupted by teachers demanding Paul to present documentation (letters) of qualification as practiced deceiver to deceiver as he described.
In short Paul was persecuted nearly to death often but lived on willing to live with the Corinthians in all tribulations, or die with them.
A very familiar pivotal passage is support for Paul's statement in 2 Cor 7:3.
Romans 8:10-14 (KJV)
"10  And if Christ be in you, the body is dead because of sin; but the Spirit is life because of righteousness.
11  But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you.
12  Therefore, brethren, we are debtors, not to the flesh, to live after the flesh.
13  For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live.
14  For as many as are led by the Spirit of God, they are the sons of God."
Paul promised the Corinthians the blessings of departing from corruptions and avoiding deceivers by way of two deaths, one dying to the flesh and sin, and the other death of the flesh in the midst of persecution for the sake of Christ. He was doing that daily as we all should strive toward more and more. Each Christian must be so anti sin as to be as though like a physically dead man is to life in the flesh, detesting sin practices unto death if necessary.  Paul was ready to finish his days on earth but held on for the sake of the Church. My support for that attitude is prevalent in the epistles of Paul.
Comment: Thank you for the response and welcome to the site. What you have provided is, to my mind, simply a thesis. That is, you provided your interpretation but made no effort to demonstrate that what you say is so by providing appropriate references. Can you please provide evidence that what you opine is accurate? It is in fact a site requirement. Thanks.


Samsung S3 will not get detected by computer

Question: I think my power plug is the problem. How can I make sure? PC's USB is working fine.
Comment: Have you installed [the USB driver](http://developer.samsung.com/technical-doc/view.do?v=T000000117)?
Answer: Download   USB Driver and Go to Device Manager->right click your device  ->select Update driver-> Select Browse from my Computer on diaglog->Browse the path where your USB Driver downloaded -> Click ok  or Select Browse from online it will take time but suitable driver will be install.
Answer: If you think there is a problem with your cable, find a friend with a working cable and phone.

Try your friend's working cable with your phone. This should work.
Try the suspected bad cable with your friend's phone. This should not work.


What's the proper terminology for nebula clouds?

Question: I'm writing a research paper over outer space (yeah, yeah, broad topic) and I'm wondering what the proper terminology for nebula clouds is.  This is an excerpt from my paper showing how I'm going to use the term:  "Outer space is the host of all the types of stars and galaxies and a lot of other interesting phenomena, such as black holes, supernovas, and ________."  Long story short, would I use "nebula clouds" or "nebulae"?
Comment: Nebulae is best, same as "supernovas" should be called supernovae.
Answer: "nebula clouds" sound a little bit redundant, because, is there any nebula that is not a cloud?
I would stick to "nebulae". (And if you want to be consistent, you should be writing "supernovae" too).
I am not an expert on this topic, but I have never seen any use of "nebula cloud" before.
Answer: The term "nebula" has been used historically for virtually any astronomical object that was fuzzier than stars. Specifically, galaxies which to the naked eye and in small telescopes looked like elongated clouds were called nebulae (e.g. the Andromeda Nebula), even though they definitely aren't clouds.
Nowadays, the term is mostly used in the context of planetary nebulae, which are the beautifully colored death breaths of low-mass stars, lighted up by a central white dwarf. These objects were originally thought to be planets, but has nothing to do with that.
Other types of nebulae are usually called by their more descriptive names, e.g. molecular clouds, HII regions, and supernova remnants. The only objects I can think of that are often called nebulae, are reflection nebulae, which are the clouds of dust and gas surrounding a young star cluster.


Ruby on Rails 3 modeling complex medical questionnaire

Question: I need to convert a medical questionnaire into an online version. I have looked at Surveyor1
, but the issue with mine is that there a lot of different "tests" or "exams" that require precise answers. For example, if the questions are about blood tests, then the user needs to enter measurements. Should I just model each test or exam separately, or is there a smarter way to do this? I would say that about half are simply yes/no/unknown type questions, and the half require entering measurements. Thank you
Answer: You can use nested attributes like in this episode : http://railscasts.com/episodes/196-nested-model-form-revised. You have other episodes here : http://railscasts.com/episodes?utf8=%E2%9C%93&search=nested+form
Answer: We had a similar issue when creating a customer survey system for a client.  Our issue was that the client needed the ability to create survey's on their own in the future - meaning anything we implemented couldn't be hard coded like you mentioned as an option for you.
In our case, while there were a couple of different scenarios they would encounter, it really wouldn't change all THAT much - it really boiled down to number answers, text answers, ranges, etc...
We added a "style" field to our questions model and implemented validations based on the style that was selected for it.  So a "number" question would check for numerical answers, etc...  We also implemented the validations client-side using js, just so they'd have more upfront info on if their answers were sufficient (time saving seems important in a medical application).  It worked well for our needs - hopefully it'll point you in the right direction.