Notation for Marginal Distribution

Question: Is there a satisfactory notation for marginal distributions? This would be one that clearly distinguishes the marginal distribution of $X$ relative to the joint distribution $(X,Y)$ from $X$ as it would be envisaged had $Y$ not been introduced.
One option might be $\mathbb{E}_Y(X|Y)$, but this seems to go beyond the basic definition of a marginal distribution.
Comment: I usually just use $p[x]$, i.e. there is no need to reference $y$ (or any other "[nuisance variable](https://en.wikipedia.org/wiki/Nuisance_variable)" that may have been omitted from the analysis!). Is there a particular context you are interested in? (Also, did you mean $\mathbb{E}_y\big[p[x|y]\big]$?)
Comment: If (X,Y) is a continuous bivariate distribution then the marginal for X denoted f is given for each x f(x) = integral of g(x,y) dy over the range of values of y. So is integrated out and similarly h(y) is defined by taking g(x,y) and integrating out x.
Comment: This is probably known by the OP and it illustrates why GeoMatt22 is exactly right. Y can be viewed as a nuisance variable that is removed by integration to give the marginal for X.  Likewise for Y, Xis a nuisance variable that ids integrated out to get the marginal for Y.
Comment: This may not be standard but I suggest that the marginal for X could be given the notation g(x,.) and the Y marginal by g(.,y) This is at least analogous to the notation for marginal means in ANOVA.
Answer: As pointed out by GeoMatt2, there is no need or even no meaning for a special notation.

"...clearly distinguishes the marginal distribution of $X$ relative to the
  joint distribution [of] $(X,Y)$ from $X$ as it would be envisaged had
  $Y$ not been introduced."

There is indeed some confusion in this question in that the marginal of $X$ is the marginal of $X$, no matter how it is derived:
$$p(x)=\int_\mathfrak{Y} p(x,y)\,\text{d}y=\int_\mathfrak{Y\times Z} p(x,y,z)\,\text{d}y\text{d}z=...$$for any completion mechanism one can dream of.
Introducing an extra-notation thus does not make sense when the function is the same.
Comment: Thank you. I seem to have become confused as a result of being confused about adjustment for confounding.
Comment: Didn't my comments from last night say the same thing?  I was expecting that maybe you would want me to write up a shorthand formula for marginalization.  Clearly there is nothing standard and the idea that it just meant integrating out X to get the marginal fo Y and vice versa was explained well before Xi'an gave this answer.
Answer: In my comments, I amplified on the comment of GeoMatt22.  The point was made by both of us that the marginal distribution for $X$ bore no relationship to $Y$ because $Y$ was integrated out.  Prior to Xi'an giving his answer, I suggested that I would like to summarize my comments in an answer because I did have a rational choice for a notation although it may not be standard.  Xi'an answered before the OP answered my comment. I am giving this answer because I am the only one so far to directly address what would be a rational notation for a marginal distribution for $X$. Here is a summary of the comments and the previous answer:

GeoMatt22 rejected any notation that included $Y$ conditionally.  He made the important point that $Y$ is a nuisance variable and said that he just uses $p(x)$. He probably didn't make it a question because his choice is not standard.

I then made three comments elaborating on GeoMatt22. Since my third comment included a notation that may not be standard but gets around the problem with $Y$ not being involved in the marginal for $X$.  Please look at the comments above before judging my answer.

Xi'an enters an answer that acknowledges the key point made by GeoMatt22 and then expresses the point differently that a marginal integrates out the nuisance variable(s).  He does not suggest a notation because, as he says, it doesn't make sense.

The OP accepts Xi'an's answer and gives a comment as to how he became confused but does not seem to have read my comments and possibly not GeoMatt22's either.

Now let me explain my answer by illustrating the ANOVA analogy. When you do an ANOVA, marginal sample averages are given a notation.  In the one-way ANOVA, the observations are denoted as $X_{ij}$ where $i$ represents the $i$th observation from the $j$th group, $i$ runs from 1 to $n_j$ for a given $j$ and $j$ from 1 to $p$ ($n_j$ observations in the group $j$ with $p$ groups).
So the notation $X_{i.}$ represents the average of the observations for fixed $i$, where the group effects are averaged out.
Likewise, $X_{.j}$ denotes for the $j$th group the average of the $X_{ij}$ where each of the $n$ observations for the $j$th group are averaged. So $X_{i.}$ = set of ($X_{ij}$) for fixed $i$, averaged over all $j$ from 1 to $p$ and $X_{.j}$ is the set of ($X_{ij}$) for fixed $j$ averaged over all $i$ in the $j$th group.
So by analogy for $f(x,y)$ denoting the joint density at $X=x$ and $Y=y$, let $f(x, .)$ represent the marginal density at $X=x$ with $Y$ integrated out and $f(.,y)$ the marginal density for $Y$ at $Y=y$ with $X$ integrated out.
Comment: While the notation links to the ANOVA model, using $f(x,.)$ for the marginal density is confusing since, in [mathematics](https://en.wikipedia.org/wiki/Function_(mathematics)#Notation), $a(.)$ denotes the function $a:\,x\to a(x)$ and thus $f(x,.)$ would denote the function $y\to f(x,y)$, that is, the joint density as a function of $y$ for a fixed value of $x$. This is the opposite of the intended meaning.
Comment: Sorry if I seemed unresponsive, but to me @Xi'an's answer addressed the "root cause" of my question in that my question was based on a misconception/confusion. Thanks.
Comment: @Xi'an The notation is a stretch.  I just thought it was an interesting idea that statisticians could relate to.  I don't really think it will be adopted but it was important to make it clear to the OP that conditioning on Y didn't make sense. I think what is currently done is exactly what GeoMatt22 does  completely eliminate the second argument. I guess you can see that I was a little miffed at the OP because he ignored or overlooked my comments and my question to him.  No knock against your answer.It was as good as any and it did gett the idea across to the OP.
Comment: I suspect the central part of the question was to distinguish between what the OP believed were two separate definitions of the marginal, although they could not differ. Defining the marginal by integrating out an auxiliary variable did not seem to cause a problem to the OP.
Comment: @Helmut  Okay. I got a little carried away because I thought my choice of notation was clever.  But it is clearly not important as you can see from my above discussion with Xi'an.  If your confusion was your main concern GeoMatt22 and I essentially addressed that in comments before Xi'an even wrote up his answer. You could check the history. What was it in his answer that rang true for you that wasn't already in our comments?

Notation for Marginal Distribution


Integrating an asymptotic

Question: Let $f \sim g$ mean that $f/g \rightarrow 1$ as $x \rightarrow \infty$. Does it follow that
$\int_{1}^{x} f(t)\, dt \sim \int_{1}^{x}g(t)\, dt$?
Answer: No. Take $f(x) = \frac{1}{x^2}$ and $g(x) =\frac{1}{x^2} +\frac{1}{x^3}$.
Comment: Well, don't both integrals converge at the same time?
Answer: This question is related to the comparison and limit comparison tests for establishing the convergence or divergence of a series or integral. Throughout my answer, I will assume that both $f$ and $g$ are (eventually) positive and continuous everywhere.
As BebopButUnsteady's answer shows, the conclusion in question is not always true. However, one could still say a little more:
Divergent case: If either one of the integrals $\int_1^x f(t) ~\mathrm dt$ and $\int_1^x ~\mathrm g(t) dt$ diverges, then the other diverges as well, thanks to the limit comparison test. In this case, it is true that
$$
\int_1^x f(t) ~\mathrm dt \sim \int_1^x g(t) ~\mathrm dt.
$$
[Both sides approach $\infty$ as $x \to \infty$.] See this post for a proof.

Convergent case: If either one of the integrals $\int_1^x f(t) ~\mathrm dt$ and $\int_1^x g(t) ~\mathrm dt$ converges, then the other converges as well, again thanks to the limit comparison test. In this case, just from the definition of the improper integrals $\int_1^{\infty} f(t) ~\mathrm dt$ and $\int_1^{\infty} g(t) ~\mathrm dt$, we have
$$
\int_1^x f(t) ~\mathrm dt \to \int_1^{\infty} f(t) ~\mathrm dt
$$
and $$
\int_1^x g(t) ~\mathrm dt \to \int_1^{\infty} g(t) ~\mathrm dt.
$$
However, of course, the two integrals might converge to different limits; i.e., we need not necessarily have the equality
$$
\int_1^{\infty} f(t) ~\mathrm dt \stackrel{\color{Red}{??}}{=} \int_1^{\infty} g(t) ~\mathrm dt.
$$
Therefore, it is not necessarily true that
$$
\int_1^{x} f(t) ~\mathrm dt \stackrel{\color{Red}{??}}{\sim} \int_1^{x} g(t) ~\mathrm dt.
$$
Comment: Your second bullet point is not correct unless you impose some continuity condition since one of the function may have a non-integrable singularity at finite $x$ which does not change its asymptotic properties at all.
Comment: @BebopButUnsteady You're right. I will assume the functions are continuous everywhere. Thanks.

Integrating an asymptotic


Port scans: 'traffic denied' VS 'close - age out'

Question: I have been investigating logs from the firewall (Juniper) and I've found out that when someone is portscanning my website, the majority of the traffic through different tcp/udp ports is denied (except for ports 80 and 443, which is allowed). However, traffic is allowed through some of the ports that it shouldn't be, for example, ports 4800, 502, 21025, 88. But after inspecting the log it also says 'CLOSE - age out'. Does that mean that the attacker managed to initiate a session but no traffic was sent for a certain amount of time ? Does the attacker get any information from these different responses ?
To clarify: I do not have access to check what is the exact firewall configuration.
Comment: Some Juniper devices also log "age out" for a TCP reset packet. So its likely the device the firewall passes the request through to does not have the port open and is sending a RST packet.
Comment: @Hector could you please provide a simple schematic (for better understanding) of the tcp connection you described for it to end in a RST packet ? Also, does that mean that the firewall is allowing the traffic through the mentioned ports ?
Comment: https://en.wikipedia.org/wiki/Port_scanner#SYN_scanning - "If the target port is open, it will respond with a SYN-ACK packet. The scanner host responds with an RST packet, closing the connection before the handshake is completed.[3] If the port is closed but unfiltered, the target will instantly respond with an RST packet." - so in a normal syn based port scan whether the port is open or closed you would expect to see a RST packet. It does suggest the firewall is allowing the packet yes. Why will depend on the firewall config.
Answer: Some Juniper devices log TCP RST packets as age out. This is to do with how the ASICs handle the timeout - see here.
A RST packet would be expected behaviour when a SYN based port scanner is allowed through the firewall on a given port. SYN scanners send the initial SYN packet to establish the TCP connection.

For a closed port most systems would reject this by sending a RST packet (thus letting the client know and not leaving them to time out).
For an open port the client would respond with an ACK. The scanner then (usually) sends a RST so the server knows it can close the connection.
Worth noting this could also legitimately be a time out. I.e. a connection is established but no packets are received within the firewalls timeout limit.

If you are seeing age out on those ports it would suggest the packets do make it through the firewall. Without seeing more information from the log, firewall configuration or server configuration it is difficult to speculate on both why these are allowed through and how far through the connection the process gets.


I'm tired of my lover. How can I break up with them and get a new one?

Question: I just wanted to know how can I break up with someone? With Spec. Treynor in particular. I want to try another one, but it seems impossible when I have someone else. For example I got Liara to the cabin with the time-capsule, but where a guide says to say I "want to be more than friends", I don't have that option and Liara only leaves the cabin after a few dialog choices...
Comment: Well, if there's a relationship with Specialist Traynor in the offing, there *is* no trouser snake.
Comment: Has Shepard finally gotten his trouser snake in check? I'm impressed. Don't recall seeing any options to break up with a romantic interest in ME3. In ME2 you could dump them at almost any time.
Answer: According to a Gamefront guide

NOTE: All serious relationships are final! You can only have one romantic relationship. Entering one will nullify others.

It seems like you confirmed this yourself with a missing dialog option.
Comment: `This is too bad, forcing players to re-play the game to try out all the possibilities?` This comment seems really funny, given how many different ways the game plays out, and seeing some of the changes you'd have to go back in time to Mass Effect 1 to see a different result for. It seems to be working out for Bioware so far! :)
Comment: Damn. I knew there was an option missing, but was hoping I could get it back. This is too bad, forcing players to re-play the game to try out all the possibilities? Bad move, Bioware :/
Comment: I understand that the important choices, like who to let live or who to pact wiith can't be turned over. But since relationships have no real impact on the game, except for one or two cutscenes, it could be changeable..
Answer: According to the romance article the only romances you can actually break up are ones you have previously romanced in either ME1 or ME2
For example, if you bed Ashley in ME1, then Miranda in ME2, then you will be given dialogue choices between the both of them and must decide which one you want to continue with, effectively breaking up with the other.  You also have the option of denying both of them and going for one of the newer ones like Cortez or Allers.

(note, answer written assuming male Shepard, see the above linked article for all possible romance options)


What are the advantages and disadvantages of a low stall angle?

Question: One advantage I can think of is when we increase the wing's angle of incidence to decrease fuselage drag and increase takeoff lift, but would higher stalling angles always be better in terms of flight safety? And how low could a stalling angle be in terms of safety?
Answer:
Increase the wings angle of incidence to decrease fuselage drag.

That's exactly how the B-52 bomber was designed and built in the 1950s.
Other very important factors are weight and airspeed in determining angle of attack necessary for flight.
What designers strive for is optimal wing area and angle of attack at cruise speed within a weight range to minimize fuel consumption.
This is why airliners are excellent gliders, with V best glide near their cruising (indicated) airspeed.
One would also sensibly limit weight so that Angle of Attack does not come too close to the stall limit. However, with adequate power, one can increase the amount of lift being produced by the square of the increase in airspeed.
This is a far safer approach than using increase in AoA to increase lift, as drag increases exponentially as AoA approaches stall.
Finally, "drooping" the nose does not affect wing AoA, but for lighter models (stored in windy places) it is good to be able to get 0 or negative AoA on the wing.  Tricycle gear can help this, with the nose wheel a little lower. Make sure you have enough elevator authority (in design) to rotate at takeoff speed.
Comment: Don't forget pilot vision: The F8U Crusader even jacked the wing up so the fuselage angle during approach and landing was low so the pilot could better see where the plane is going.
Comment: The B-52's wing has a relatively high angle of incidence because the B-52 cannot rotate at takeoff due to the very aft landing gear, not to decrease fuselage drag.
Comment: @sophit well, after the gear is up then it really gets to be an $airplane$.  Lowering fuselage drag helps.  I wonder, instead of swinging the wing back and forth, perhaps an adjustable incidence ...
Comment: Yes, after the gear is up then it really gets to be an airplane but with a wing with an incidence so high that it has to fly with the nose slightly pointing downward. This doesn't help in reducing drag.
Comment: those B-52 flaps have such a large chord & extend so far back, that they behave like a variable incidence wing
Comment: @jkztd bingo! And *slats* can be used to *lower* wing AoA.  Fuselage drag bears study and should be minimized.  Variable wing incidence may help.


Referencing future ideas in abstract of a research paper

Question: Is it bad to reference ideas which have not yet been defined in detail within the abstract for a research paper? For example, if I have a section (lets say section 4) in my paper that defines a new concept such as "The Quadrilateral Optimization", within my abstract, would it be acceptable to write "The Quadrilateral Optimization (§4) excels specifically with points that are randomly generated."
Answer: A paper containing a concept X can be cited with respect to X if any one or more of the following applies:

X is clearly defined
An intuition of X is provided
A constraint of X is explained
An application of X is experimented
An application concerning X is accounted
A logically contradicting definition of X is theorized

A mere inclusion of the name of the concept X does not mean that it deserves to be cited
Comment: So does this still apply if "X" is ONLY defined within the paper that I am writing? Or must it be defined in another source?
Comment: Just to clarify, "X" in this case is a new idea that has not necessarily been defined elsewhere, only later on in the paper I am writing.
Comment: @Arman: If by *'defined'*, you mean clearly defined and you are sure that the concept *X* has not been defined before elsewhere, then by all means you may cite the paper with *X*.


What happened to Dr. Vahlen?

Question: Are there any references in XCOM 2 as to what happened to Dr. Vahlen? Dr. Vahlen was the Chief Scientist who had Tygan's now current role, but she is no longer seen at all, and I can't find any reference in-game referencing her, or any voice comms talking about her, despite the wiki saying that they talk about her being missing.
Comment: Legends say that if you say "Vahlen" three times in front of a mirror then blow the mirror up, she appears.
Comment: I think it was touched upon in the novel but I've not read it and I've not been able to find a good synopsis for it before.
Comment: I wonder if she will turn up in future DLC. It seems possible given the references stated above and how her storyline isn't wrapped as well the other major characters from XCOM EW
Answer: She's mentioned in the XCOM Archives in the Commander's quarters (bold emphasis mine):

Vahlen, Moira - STATUS: MIA
Vahlen, Moira. Birthdate Unknown. Doctor Moira Vahlen, Chief Scientist
  serving XCOM at the onset of the invasion in March of 2015. Very
  little information about Dr. Vahlen still exists following the
  destruction of XCOM's original headquarters. Central Officer Bradford
  is now the only living member of the staff to have had personal
  contact with her, and he generally remains aloof when pressed for
  further information. Notes and various remnants of data from the
  original XCOM database indicate an aggressive pursuit of alien
  material sought for study by Dr. Vahlen, with limited concern for the
  potential outcomes of these theoretical research fields. Dr.
  Vahlen's status following the destruction of XCOM HQ is unknown, no
  further contact has been established.

Other Mentions
Many of the characters will also mention her from time to time in the Avenger:

Tygan will mention having heard that his "predecessor" was "something of a brute" when it came to alien interrogations and autopsies.
Shen will mention coming across some notes written in English and broken German.
IveLostMyLibraryCard points out some additional references.

Additional quotes:

We've been picking up some weird transmissions lately; it sounds a little like German, but it's hard to tell.

I've been digging through some of the old data files Central has been
  holding on to since before the war. I keep running across notes
  scrawled in English and what looks like broken German. I should
  probably ask him about it.

Speculation
I have my suspicions that Vahlen was actually captured by the aliens and used as the basis for the Codex unit, but that's pure speculation at this point.
Answer: Vahlen is mentioned in the prequel novel. Minor spoilers follow.
The prequel novel, in the large, deals with the Resistance's efforts to find and capture the crashed alien vessel which becomes the Avenger.
Early on in the novel, the protagonist and his squad travel via submarine to a volcanic island off the coast of South America. That island contains a hidden Resistance research base known as 'Wunderland', which is headed by Dr. Vahlen.
Unfortunately, one of the protagonist's friends has some sort of tracker embedded in her, and ADVENT forces attack the island. The protagonist's squad heads to the surface to fend off the enemy forces. While they're doing so, the base self-destructs.
By the time they've fought off the ADVENT troops the submarine's departed. They explore the now-wrecked base and discover a diversion - a bunch of wrecked helicopters and dead bodies intended to fool any ADVENT forces looking for survivors. A trap door leads to a cove where the protagonist's squad commandeer a boat to continue their journey.
Vahlen's fate is left unmentioned, although the protagonists theorize that she and whoever survived the assault fled on boats (or even a second submarine) after self-destructing the base.
In short — if the prequel novel is considered canon, Vahlen was alive, well, and conducting research for the Resistance weeks or (at most) months before the actual start of the game, but her current whereabouts are still unknown. She may have died escaping her base, been captured by ADVENT while/after escaping, or slipped away and made it to another Resistance haven.
Comment: The book is called *XCOM 2: Resurrection*. You can get it on Amazon (or presumably other bookstores) [e.g. here](http://www.amazon.com/XCOM-2-Resurrection-Greg-Keyes/dp/1608877124). It was an alright read; I wasn't blown away by it.
Comment: Cool, thanks! Just curious, is this novel like a published book that I could purchase or is free? Or was it a preorder bonus or something?
Answer: Central mentions her from time to time when you hang around in the avenger long enough. Quotes I've personally heard are
"broken transmissions in what could be German have been broadcast lately"
"Dr valhen is missing but I need to believe she's still out there somewhere"
"valhen went missing after xcom fell but I can't imagine she would just give up so easily, not with earth's freedom at stake"
Comment: There's also an entry for her under `Command --> XCOM Archives`, saying basically the same thing.  I assumed her whereabouts would be revealed later in the game, but if not, maybe in a DLC (maybe [Shen's Last Gift](http://store.steampowered.com/app/426321/)?)
Answer: There's another reference to her in the game: If you play the tutorial, when you're waking up after having the implant removed and Bradford talks of losing good soldiers, you see a photo of Bradford, Shen and Vahlen at the time of EA/EW.
Answer: WHAT FOLLOWS BELOW THIS, IS INFORMATION THAT CAN BE QUALIFIED AS SPOILERS. DO NOT READ IF YOU DO NOT INTEND TO SPOIL THE STORY FOR YOURSELF!

 In the most recent addition of XCOM 2, the Alien Hunter DLC, there is hinted at several NEW campaign missions. I have now endured ONE of these campaign missions, and Vahlen is definitely playing a part. She is not found in the first mission, however. I have, as of yet, not come across other missions, or other implications that she is found later on.
During this mission it is heavily implied that Dr. Vahlen is walking on borderline ethically acceptable boundaries, or even overstepped them. That is all I'll say.

What happened to Dr. Vahlen?


A user in an Owner's group cannot Add Users, only Groups

Question: I would really appreciate someone's help if possible. I have set up a site with a series of sub sites, which I thought was working fine until I asked someone I had set up as an Owner of a sub site to do a test and try to add a new user. Although they have full control they only get the option to add a new group. They are in the Members group of the parent site and the permissions have been broken. I wondered if this had anything to do with it? I'm clutching at straws a bit here ... Any ideas, would be really helpful ... Thanks
Comment: I created an "Core Team" Group and added some users to it. Then I set this "Core Team" Group as the Owner to other groups in my share point. However the users from "Core Team" are not able to invite other users to the groups. As a matter of fact, they are not able to see these groups. The Core Team are not site owners and don't have Full Control. They are not supposed to be Full Owners. Their responsibility is to manage access to the groups assigned to them
Kindly assist
Answer: Exactly, as in the previous answers, groups are managed only through their owners, not through the site owners. This was weird for me at first, too.
However, to work around that: Add the site owners as the owners for the newly created groups!
Answer: The above sugestions would work but would create a dangerous security vulnerability since now any member of the group would be able to add new members.
What you want to do is to create a new group that contains the various adminstrators of your site and asign this group as the owner of the group. This way any administrator can add new members but only administrators have this ability.
Answer: The ability to add new users to the group is generally controlled by "Group Settings":

As a site collection admin, select the group and select Settings > Group Settings to access it.
Answer:
You need to change the Owner Option of the Group Owner.(In your case the SharePoint group to which you want to give access to add user to this group).
It doesnt matter if they have a full rights or not on this site they can still add users to this group if they are owner of this group.


Blender->Unity materials problem

Question: I have a pproblem with materials and their texture. I have a model with 1 material called 'Car_Jack', after i put my .blend file into unity, unity adds 'Car_Jack__Car_Jack_UV', which is white material without textures. I have the only one UV map, called 'Car_Jack_UV'. What is wrong with Unity/Blender?
Comment: In Blender, is it actually a material on the object or just a texture that's been UV unwrapped to the model? You could probably open up the .fbx file (if it's non-binary) and look yourself to see if it's exporting the materials which will help you diagnose if it's Unity or Blender
Comment: Unreal engine reads all materials from this fbx correct with textures and so on. So it's 99% Unity fault. It's material with texture on it in Blender. And also unwraped.
Answer: Try exporting your Blender scene as .fbx and import the fbx from Unity
Comment: I used .fbx too. Almost the same problem.

Blender->Unity materials problem


My landlord won't provide me appropriate documentation after charging me a lawyer fee

Question: I recently ended my lease on 01/31. My landlord had charged us a lawyer fee for adding someone to the lease. He was giving us random amounts and when I asked for receipts, paperwork, and proof of transaction,  he failed to give me any of those. On the day of 01/31, he proceed to charge us ( a different amount that was originally stated) and handed me a receipt that was dated 01/31. He deducted it from my security deposit without giving me a chance to review it. I feel like I am being taken advantage of.
Comment: Where is this? Landlord/tenant laws vary by country, by state or province, and often by locality, so the city or other locality may matter. Also, did your lease have any provision allowing for such fees?  Note that while we can often help people learn what the law requires or permits, we cannot advise on what someone should do in a specific siutuation.
Comment: What exactly is your specific legal question?
Comment: Back when I was a student, I remember something similar, but the charge ($50 iirc) was actually specified in the lease and it wasn't a "lawyers' fee" but stated something along the lines of an administrative fee for making a new lease with the new tenants. Yeah, they were probably making money on that alone, but it was specified in the lease... (FWTW, $50 was also the "deductible" we had to pay for any repairs the landlord made at our request.)
Comment: Also, since the money is being deducted from your deposit, it sounds like you're leaving, otherwise you'd have to pay that fee on top of the rent. In general,                                 people are more likely to "screw you" if they think they never have to do business with you again...
Comment: As an aside, in some European countries, to get the full protection of the law, the lease has to be notarized. (By this I mean that if it's not notarized, some clauses are overridden by the "standard" provisions in the law.) And the public notary fee can vary... so a landlord may not know it an advance, although I think this is a somewhat rare occurrence. And whether the tenant has to pay (some of) it... is again a different matter.
Answer: Review the terms of the lease, and determine (a) what deductions can be made from the security deposit, and (b) what charges can be made for lease changes or tenant changes. If the amount and type of deduction for "lawyer fee" is included in either of those areas, then it sounds like the landlord did what the lease allowed. But if not, then the deduction could be improper. If you're in the U.S., you could see a lawyer specializing in landlord-tenant law; or there might be a "tenants' union" in your area, which is usually a nonprofit organization that provides information for tenants to exercise their rights.
Answer:
He deducted it from my security deposit without giving me a chance to review it. I feel like I am being taken advantage of.

Indeed you are, unless this issue in particular is explicitly provided in the terms of the lease. The reason why I use italics for "explicitly" is that the act of adding someone to a lease is not complex enough to warrant assistance by some lawyer. A landlord is not entitled to unreasonable expenses, especially if he failed to notify you beforehand so that you can make an informed decision on how to proceed.
It is unclear whether you question the legitimacy of the receipt, but you are entitled to proof of the alleged expenses. It seems that you have a viable claim under multiple legal theories such as breach of contract and conversion.
You did not specify your jurisdiction and the amount in dispute. In some countries the tenant might be required to undergo an "alternative dispute resolution" (ADR) venue instead of court. The amount in dispute is also relevant for determining whether the matter would have to be litigated in Small Claims Court or the non-US equivalent. If the lease provides for ADR, then that takes priority regarding how to proceed.
Be sure that your subsequent interaction with the landlord be in writing, since that might make it easier for you to prove your claims.


How do I find out which snaps are using which versions of the runtime

Question: I have Gnome 3.26, 3.28 and 3.34 on my machine (Ubuntu 18.04) and want to know if I can get rid of any of them to save disk space. Is there some kind of snap command I can run that will show me?
Comment: Yes, I expect there probably there is. And I would like to know what it is. Hence my question! `snap info  --verbose` doesn't give me that dependency info.
Comment: I'm not quite understanding your question. By definition, snaps are self-contained binary blobs, so there are no external dependencies. This is by design. However, if you're asking whether you can safely delete snaps such that their removal won't adversely impact your Linux environment, the command to run would be `sudo snap services` which lists active services employed via snaps. For validation, you can also run `sudo systemctl status snap.`. I hope that helps answer your question.
Comment: @cachius `snap list` gives you the list of snaps - and I see I now have Gnome 3.38 and Gnome 42 as well on my machine! But I first spotted this looking at disk space usage.
Comment: @richbi running `sudo snap services` lists a canonical live patch service and a desktop integration thing - but nothing that says "gnome". My question was - as you have I think worked out - is "what will happen if I delete these gnome snaps?". I think the answer is here: https://askubuntu.com/questions/1155957/two-different-versions-of-gnome-runtime. Bur I still don't know where these snaps came from or what ubuntu software relies on them.
Comment: Probably, there is a command that allows you to see details on a snap, including which other snaps it would need. The full documentation of snap is here: https://snapcraft.io/docs
Comment: How do you get the list of Gnome versions?
Comment: On [my answer](http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1851-17402003000100005) I mention that [`gnome-...` snaps are just backends for GTK snap apps](https://askubuntu.com/a/1345181/349837). If you don't use snaps you can remove them. Also "it's possible to remove all the snaps, and remove snapd... the desktop will function fine" (from Popey, former snap developer; now developer of [unsnap](https://github.com/popey/unsnap)).
Answer: Snap Commands to track connections

You may use command below to list all slots/plugs used.
snap connections

or for specific app, example:
$ snap connections snap-store
Interface                 Plug                                      Slot                             Notes
appstream-metadata        snap-store:appstream-metadata             :appstream-metadata              -
content[gnome-3-38-2004]  snap-store:gnome-3-38-2004                gnome-3-38-2004:gnome-3-38-2004  -
content[gtk-3-themes]     snap-store:gtk-3-themes                   gtk-common-themes:gtk-3-themes   -
content[icon-themes]      snap-store:icon-themes                    gtk-common-themes:icon-themes    -
content[sound-themes]     snap-store:sound-themes                   gtk-common-themes:sound-themes   -
dbus                      -                                         snap-store:packagekit-svc        -
dbus                      -                                         snap-store:snap-store            -
desktop                   snap-store:desktop                        :desktop                         -
desktop-legacy            snap-store:desktop-legacy                 :desktop-legacy                  -
...

or probably best option with reverse search:
$ snap connections gnome-3-38-2004
Interface                 Plug                                       Slot                             Notes
content[gnome-3-38-2004]  firefox:gnome-3-38-2004                    gnome-3-38-2004:gnome-3-38-2004  -
content[gnome-3-38-2004]  snap-store:gnome-3-38-2004                 gnome-3-38-2004:gnome-3-38-2004  -
content[gnome-3-38-2004]  snapd-desktop-integration:gnome-3-38-2004  gnome-3-38-2004:gnome-3-38-2004

It may be worth adding, search by interface too:
$ snap interface content | grep gnome
  - firefox:gnome-3-38-2004
  - snap-store:gnome-3-38-2004
  - snapd-desktop-integration:gnome-3-38-2004
  - gnome-3-38-2004:gnome-3-38-2004

Explaining snap connection
Due to the objective nature of snaps. Snap runs regular apps in confined environment. So each snap app that depends on another app, its developer has to declare the "connection" (or we may say plug-slot), mook765's answer here has used it for his approach (snap.yaml contains the dependencies declaration). The type of the connection is called "interface" content[gnome-3-38-2004]. And each connection composed of (one "slot" which is connected to either no, one or many "plugs"). Slot gnome-3-38-2004:gnome-3-38-2004 in this case is provided by gnome core snap, app declares and uses a plug ex:snap-store:gnome-3-38-2004 to that slot.
A good reference to read more: snapcraft.io: gnome-3-38-extension - plugs
Removing gnome-extension snap (Test)
Connections may auto/manually be connected or disconnected, that why I expect snap doesn't force uninstalling of dependent apps. I tested it within Ubuntu 22.04 in Virtual-box. Snap disconnects plug/slot and then removes the app. The app fails to run anyway.
$ snap remove gnome-3-38-2004
gnome-3-38-2004 removed

$ snap connections snap-store
Interface                 Plug                                      Slot                            Notes
appstream-metadata        snap-store:appstream-metadata             :appstream-metadata             -
content                   snap-store:gnome-3-38-2004                -                               -
content[gtk-3-themes]     snap-store:gtk-3-themes                   gtk-common-themes:gtk-3-themes  -
content[icon-themes]      snap-store:icon-themes                    gtk-common-themes:icon-themes   -
content[sound-themes]     snap-store:sound-themes                   gtk-common-themes:sound-themes  -
dbus                      -                                         snap-store:packagekit-svc       -
...

$ snap-store
ERROR: not connected to the gnome-3-38-2004 content interface.

$ firefox
ERROR: not connected to the gnome-3-38-2004 content interface.

Comment: Interesting. So, for your example, it looks like the `gnome-3-38-2004` snap is used for the `firefox`, `snap-store` and `snapd-desktop-integration` snaps. If you were to remove the gnome snap, presumably those other 3 snaps would be affected/break/need to be uninstalled as well. Do I have that right?
Comment: so why is firefox and chrome also using such an old library from 2004?
Comment: BTW, I have no idea what connections, interfaces, plugs or slots are when it comes to snaps. I thought a snap was just a different way if installing software - so all these other terms are brand new to me. I guess I'd need to read the docs... Thanks for your help
Comment: @charlesdeb You are right however  you don't have to remove dependent apps, but they may have limited/partial functionality or completely break. (I didn't test it, i will soon, I have Ubuntu in a virtualbox).
Comment: @charlesdeb About idioms, Snap create  isolated runtime environment for each app. So each app needs another app, its developer  has to declare the "connection", type of connection is called  "interface". And each connection composed of (1 "slot" and  0 or many "plugs"). Slot in this case is provided by gnome core snap, each app that depend on gnome, declare and use a plug to that slot.
Comment: @rubo77 Snap core is built after releasing Ubuntu. So they are released and updated in sequence: Ubuntu 22.04 -> core22 -> Apps migration. They are kind of slow in stable channel, only if some prefer installing from edge channel.
Comment: Note that this doesn't seem to list the base (core18, core20, core22, and so on).
Answer: You can find out the dependencies of a snap by examining it's snap.yaml-file which is
/snap/<snapname>/<revision>/meta/snap.yaml

The commands
~$ grep "default-provider:" /snap/*/*/meta/snap.yaml
~$ grep "base:" /snap/*/*/meta/snap.yaml

will produce a list of all needed dependencies for all installed snaps, a dependency not listed can safely be removed. See the example in this answer.


Bycicle on Shabbos for adults.

Question: Why it is forbidden. Uvdin dechol? But on weekdays I have no free time for such pleasure activities. We have an eruv in my town.
Answer: It is assur for a few reasons
For one as you mentioned because of uvdin dechol, is not subjective. Rather it's defined as something that is primarily a non Shabbos activity. So just because you have no time to do it during the week doesn't remove the technical defintion or classification of the act of biking.
Secondly it's forbidden to ride it in a place where there is no eruv.
Furthermore it is forbidden because it's common to fix the chain or the spikes if it breaks. So it's forbidden for that fear.
See here
See Rav Ovadia in Yalkut Yosef as well:

יש להורות למעשה שלא לרכוב על אופניים [המיועדים לאנשים גדולים] בשבת.
  ואין לפרוץ גזר בזה. [ילקוט יוסף שבת כרך ה עמוד נו]. ונכון מאד להחמיר
  שלא לנסוע בשבת על אופניים, אפילו כשרוצה ללכת לדבר מצוה, וכמו שהסכימו
  כן הרבה אחרונים משום עובדין דחול. ובאיסור שבת החמורה ראוי לחוש
  לדבריהם להחמיר. [יביע אומר ח''י חאו''ח סימן נד אות יב, ושם בהערות על
  רב פעלים ח''א בתחלה]. אבל אופניים קטנות תלת אופן [שלש גלגלים] המיועדות
  למשחק הילדים, מותר להניח לילדים שישחקו בהם בשבת, באופן שאין שם בטריה
  ולא נדלקת מנורה. [ילקו''י דיני חינוך קטן עמוד רטז]

See here as well with a bit more clarification into the opinion of Rav Ovadia:

Maran Harav Ovadia Yosef Shlit"a (in his Chazon Ovadia-Shabbat Part 4
  page 43, as well as in his Responsa Yabia Omer Volume 10 in his
  comments on the Responsa Rav Pe'alim) agrees that riding a bicycle on
  Shabbat is prohibited based on what the Gemara in Masechet Shabbat
  (113a) writes, "'If you shall turn away your foot because of the
  Shabbat-by not making your ways,' your mode of walking on Shabbat
  should not be like your mode of walking during the weekdays." The
  Poskim derive from this Gemara that one may not run on Shabbat, as we
  shall discuss in the following Halacha.

>

> Thus, since bicycle-riding is meant for traveling a long distance
  which is not the usual way of walking on Shabbat, it is forbidden to
  ride bicycles on Shabbat. He proceeds to bring many sources to defend
  his opinion, one of which is based on the Gemara in Masechet Beitzah
  (25b) which states that one may not go out in a chair on Shabbat. This
  refers to the custom of an important figure sitting in a chair and
  being carried around by people to his destination of choice (as is
  common in some lands in the Far East even today). Our Sages prohibited
  this practice on Shabbat, for this is not respectful to the Shabbat as
  this is considered a weekday mode of travel. Maran Shlit"a brings
  other reasons to be stringent as well.

>

> Thus, halachically speaking, one should not be lenient to ride a
  bicycle on Shabbat; even if one is doing so for the purpose of
  performing a Mitzvah, one should still act stringently regarding this
  matter. We shall, G-d-willing, discuss the laws regarding
  bicycle-riding for children in the Halacha that will be published on
  Thursday.
Comment: Thanks for the answer.But why riding is inside uvdin dechol?? Let's say it is a kick scooter, so therr is no opportunity to fix technical stuff. We have an eruv.
Comment: @JosefKlimuk I'm not familiar with that type of bike. There are some poskim that say it would allowed of there is no chashash of coming to fix it. But it doesn't negate the uvdin dechol issue
Comment: Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/76317/discussion-between-josef-klimuk-and-shoel-umeishiv).
Comment: Regarding rich men carried by others - it was his day by day way of travelling, so for him to travel by feet was a shinui, but we have to deliberate on the question wether riding bycicle is so regular way to get to destination, or rather pleasure activity. IMHO
Comment: @JosefKlimuk how, may i ask, is that called a shinui (abnormal way of preforming a function)? Shinui would be if he walked on his knees (even that isn't that simple)
Comment: I meant, like in dinei de muktze, that by restrict himself from muktze things rich will make a difference between weekdays and shabbos.

Bycicle on Shabbos for adults.


elasticsearch.exceptions.NotFoundError: NotFoundError(404, u'search_phase_execution_exception', u'No search context found for id [id_num]')

Question: I am trying to retrieve a large number of documents from an Elasticsearch index, the query to elasticsearch is a simple exists query. The actual number of documents returned by the query is 71790 so in order to process them correctly I am using the helpers scan function, helpers.scan(elastic_search,query=doc, index=index,size=1000, scroll='1d'). What my script does is to retrieve all the documents that contain a certain field, which I call temporal field, in order to assign the value of that temporal field to the non-temporal field of that same document.
Initially I had a scroll time of 25 minutes but as I was getting this error I decided to increase it to 1 day to see if it was really a problem of the scroll time but I still get this error. Obviously the code doesn't take 1 day to run, when it takes about 50k documents to be parsed this error pops up. Everything I find on the internet is that it is due to the scroll time but I have already seen that this is not so because I have set it to 1 day and still the error pops up after about 5 minutes.
Does anyone have any idea what could be causing this error? If you need more information about the node or whatever, feel free to ask for it, I don't know exactly what information I should add.
Thank you all!!!
The specific error is as follows:
    for hit in result:
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/elasticsearch/helpers/actions.py", line 459, in scan
    body={"scroll_id": scroll_id, "scroll": scroll}, **scroll_kwargs
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/elasticsearch/client/utils.py", line 84, in _wrapped
    return func(*args, params=params, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/elasticsearch/client/__init__.py", line 1307, in scroll
    "GET", "/_search/scroll", params=params, body=body
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/elasticsearch/transport.py", line 358, in perform_request
    timeout=timeout,
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/elasticsearch/connection/http_urllib3.py", line 257, in perform_request
    self._raise_error(response.status, raw_data)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/elasticsearch/connection/base.py", line 182, in _raise_error
    status_code, error_message, additional_info
elasticsearch.exceptions.NotFoundError: NotFoundError(404, u'search_phase_execution_exception', u'No search context found for id [12671416]')```

Comment: @Avision didn't quite fix it but behavior got better when I increased the timeout parameter
Comment: hey there, I'm having the same problem right now. Did you end up solving it?
Comment: @avison I have also run into this issue, would be happy to hear about possible solutions.
Comment: I saw a discussion of this indicating that the timeout parameter is key and that the API isn't really meant for using to slowly go through data and process it, but on the other hand it seems that as long as the timeout parameter is long enough it should work. Here's the link: https://discuss.elastic.co/t/what-does-no-search-context-found-for-id-mean/103316/9
Answer: resolving exception when the index is not created yet :
elasticsearch.exceptions.NotFoundError: NotFoundError(404, 'index_not_found_exception'

check if the index is created


Can you really put 2 transformers in parallel connected to a single voltage 220VAC 60hz?

Question:
The 10 volt secondary transformer will be used to ATMEGA328P while the 25 volt primary transformer will be used for logic gates.
Comment: Depending on transformer ratings, you may have some trouble finding a shared fuse that will adequately protect the 10 VAC transformer while allowing enough current for both of the transformers at full load.
Comment: As a terminology note, when talking about transformers the words "primary" and "secondary" will generally be understood to be referring to the "input" and "output" sides of the transformer.  Your usage of *"the 25 volt primary transformer"* is understandable enough, but given that we're talking about transformers it could be confusing and would be better to phrase it another way (ie: the "main" transformer, the 25V transformer, etc).  Otherwise, we end up saying things like *"the primary transformer has a 25VAC secondary, but, like the secondary transformer, has a 220VAC primary"*  0_o
Answer: Yes, you can connect transformer primaries in parallel - after all, EVERYTHING you connect to your house wiring is connected in parallel.
Incidently, the switch in your schematic is wired incorrectly - exchange terminals 2 and 3. As shown, the switch will have no effect, and the circuit will not get any power.
Comment: Thank you for reminding me about the switch that was wired incorrectly.
Answer: No problem at all doing this; in fact the whole electrical distribution network is done in this way. With some care you can also parallel the output of the transformers (if they are in phase, same voltage and so on) to raise the available current.
If possible it could be better to use one transformer with two separate winding: it will cost less and primary losses will be somewhat reduced.
On the other hand I've seen pro audio equipment with two separate transformers to completely avoid interference between the logic and the analog section. A bit extreme but it works.
Answer: Yes. Compare that to your house, all the loads and devices are separately plugged in so they are parallel.
Answer: If a parallel combination of two transformer primaries is driven by a low-impedance source (one that supplies a voltage that is relatively unaffected by the load imposed by the transformers), and there exists only a single-point connection between the two secondaries, the behavior of the overall system may be modeled by evaluating each transformer separately as though it were an ideal transformer, adding some "uncertainty factors" to accommodate the difference between ideal transformers and those that are actually built, and then adding the current demands.
If a series combination of two transformers is driven by a high-impedance current source (one that supplies a current that is relatively unaffected by the voltage drop across the transformers), the behavior of the overall system may likewise be modeled by considering the transformers separately and combining their effects.
It's possible to wire transformers in parallel or series in other scenarios that don't meet those criteria, but modeling the behavior of such systems is much more complicated.  Fortunately, your schematic appears as though it likely fits the low-impedance-source scenario which allows easy analysis of parallel-connected transformers.
Answer: Yes, You can connect them in parallel or even series.
Comment: It won't hurt anything to put them in series, but the circuit won't work as expected.
Comment: It was general comment about transformers that they CAN be connected in series.


How can i link a group or verticies/edges/faces to be easily selected with the "L" key?

Question: I am not very experienced with blender so apologies if what I'm saying is either obvious or complete nonsense.  I have a model with 4 separate parts that I would like to rig.    When I use the "L" key to select them, it selects mostly the entire piece but a few edges are left out and stick to the main mesh.     I have gone and manually selected these pieces and moved them out of the way for now, but when I need to rig it later, I will need to easily and quickly select them using the L shortcut. How can I join these faces and define a part to my model so I can select the entire body without missing these faces?
Comment: It's hard to understand, but L will select the vertices that are connected, not the ones that are separate. And of course it won't select any mesh that is not part of the same object
Comment: Clearly either UV seams aren't displayed for some reason - pressing Numpad + a few times helps in such situations - or unselected faces aren't connected to the rest of the piece. Try pressing A, M, B to merge all vertices by distance.
Answer: It was just the vertices not being connected at some places. If anyone else encounters this problem, make sure all vertices are connected. Use the merge tool and select merge by distance and set it to something really small to get rid of those double vertices. Worked for me!


How to change my profile picture on my network profile?

Question: I've tried changing my profile picture according to How do I change my profile picture, or avatar? , and it worked fine for all sites. However, on my network profile, I still see picture from my associated Google account. How do I change this one?
Answer: If you don't have a profile there, it automatically syncs to your oldest profile on its own schedule irrespective of clicking on the button to copy to all sites. I manually triggered the sync for you and it's updated now.
If you ever do create a profile on stackexchange.com, you'll have to copy it over manually.
Comment: @Sonic It still creates the profile once you're back on stackexchange.com, at least for now.
Comment: It's no longer possible to create profiles on stackexchange.com, as its login page now redirects to MSE's login page, as part of the discontinuation of OpenID.


Direction of wave propagation unchanged after superposition?

Question: It's quite confusing.Principle of superposition states that the amplitude of two superposing wave eqauls their indivisual amplitude vector sum.But what about direction.Souldnt't wave direction of propagation should also add up and the most confusing part is that the wave continue traveling unchanged after superposition why is it show?Why the change is not permanent?
Answer: The direction does not change due to the same superposition principle.
Let's look at two waves, red and blue, at the diagram below.

The waves intersect and interfere with each other in the area A. The direction of the red wave at point B, beyond the intersection and interference with the blue wave ("after superposition"), should not be affected by this interference, because, according to the superposition principle, the field at B is the sum of the fields produced by the red and blue waves at point B, when they act alone, but the effect of the blue wave, acting along at point B, is obviously zero.
Therefore, the field at B is affected by the red blue only and, therefore, the direction of the red wave at B should be the same regardless of the presence of the blue wave and the interference between the two waves at A.


Regarding new rules for getting a tourist visa for Egypt

Question: I am a Canadian citizen, visiting in Malaysia right now, want to go to Egypt. I read the rules for visas changed in March 2015, but also read that change was reversed or something. I'm wondering if anyone would know if I can get a visa when I arrive there or not.
Comment: I'm curious where did you read the rules had changed ?
Comment: @blackbird57: No idea where the OP saw it, but it's mentioned on [Visa policy of Egypt](https://en.wikipedia.org/wiki/Visa_policy_of_Egypt) (with sources).
Answer: It seems you can still get a visa on arrival in Egypt, quoting the Egyptian embassy in London:

In addition to UK and EU nationals, citizens of the following
  countries can obtain visa upon arrival at any of the Egyptian ports of
  entry: Australia, Canada, Croatia, Georgia, Japan, New Zealand,
  Norway, Macedonia, Republic of Korea, Russian Federation, Serbia,
  Ukraine and USA.

The Timatic-based web tool from Emirates also says the same thing

Holders of normal passports issued to nationals of Canada can obtain a
  visa on arrival for a max. stay of 30 days. Fee: single entry: USD
  25.-; multiple entry USD 35.-.


Azure .ccproj is not supported by this version of application

Question: Recently started developing azure cloud services via visual studio 2013 ultimate, last week everything was working fine and I could create a .ccprog file for my cloud service. I decided to format my PC on monday so re-installed VS2013 and the azure SDK v2.5 oof which I was using before but now when I try and create a new azure cloud service project and select the WCF service web role I get a error saying that "it cannot be created due to the .ccproj file not supported by this version of application. please use a version that supports this type of project file." I think that VS isn't recognizing the SDK but not sure, when I select help the VS site says please update your version of VS but it is already the latest VS2013.4, any help would be great, thanks
Comment: no its a .ccproj (Azure cloud service file) still need to edit the typo
Comment: Similar question [opening .ccproj file in VS 2012 Express for web](http://stackoverflow.com/questions/16646245/opening-ccproj-file-in-vs-2012-express-for-web) has an idea  to install expected version of SDK
Answer: It seems your csproj holds a version of an old Azure SDK version. So you should update it.
Here a quick step by step:
<code>1) Unload the project file (Right click on project, click "Unload project")
2) Edit the project file (Right click on unloaded project, click "Edit X.csproj")
3) Change the product version to 2.5
<ProductVersion>2.5</ProductVersion>
4) Change the Azure tools version to 2.5
<CloudExtensionsDir Condition=" '$(CloudExtensionsDir)' == '' ">$(MSBuildExtensionsPath)MicrosoftVisualStudiov$(VisualStudioVersion)Windows Azure Tools2.5</CloudExtensionsDir>
5) Save the project file, and reload the project
6) This should activate the conversion wizard which will then make changes to your .csdef file, adding the following schema version attribute:
<ServiceDefinition name="SentinelWebAzure" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition" schemaVersion="2012-05.1.7">
NOTE: If you are getting a build error complaining about the schema version, that is because you dont have the right cloud extension dir setting applied.  See step #4.
</code>
Source: http://mvolo.com/visual-studio-build-and-publishing-problems-after-upgrading-to-azure-1-7-sdk/
Comment: thanks for the reply but I cant unload a project file as its not creating one, I unloaded an old .ccprog file from when it worked and in the solution explorer it says "the application is not installed"


How smart card with client certificate is used during SSL/TLS session

Question: Precisely, can I remove smart card from card reader once I successfully started a SSL/TLS session? Will website still 'see' my client certificate (public key) after I removed card from the reader and navigated on the website? Will I still be able to communicate with website in the same SSL/TLS session?
Answer:
Precisely, can I remove smart card from card reader once I successfully started a SSL/TLS session?

Yes. I think that is the most likely scenario. The client cert is used to establish the initial connection and negotiate a SESSION KEY. This is the initial session negotiation. After that, you can theoretically RENEGOTIATE any time the server (and sometimes the client, too) feels like it. But that depends on the specific web app. However it would be out of the ordinary, and I don't think it's very likely.
But just try it yourself and/or ask the admins of the web app.
Comment: Note that the client itself may be programmed in such a way that the connection is severed whenever the card is made unavailable by the user (to protect the user from others to use the authenticated session).
Comment: "But just try it yourself and/or ask the admins of the web app." - My problem is I don't have a card nor reader and don't know who to ask :-)
Comment: @MaartenBodewes: I was thinking  about regular browsers. I don't think they get to do that.
Comment: @StackzOfZtuff You may be right, although e.g. IE tends to rely on OS functionality, which - at least in principle - should be able to detect card removal.
Comment: @MaartenBodewes: I'm no programmer, but this sounds like something that you'd need a plugins help for, though. (Flash, Java, ActiveX) And not something that has a regular HTML5 API.


Can you help identify my roller door side track tape?

Question: The "tape" on my roller door is getting old and needs replacing because it's causing a lot of friction against the guides so the door does not move smoothly. I need help identifying the name of this part. I can post more photos if necessary. The "tape" appears to be rubber with a woven fibre type coating.
Comment: I'm not a garage door expert by any means, but some internet searching has failed to turn up any parts for the door itself. I'm not sure you'll be able to find a replacement for just the "tape" along the edges. I'd suggest contacting a couple of local garage door companies, though they may only do standard residential sectional doors. Maybe get hold of the owner/manager of a self-storage place that has roll up doors to find out who they have do maintenance on their roll-up doors. Based on the condition of the door itself in that close up, it might not be bad to replace the whole thing.
Answer: Its called Nylofelt.
B&D claim it as their invention. Good luck finding it for sale.
Comment: Who is "B&D"? Is that "Black & Decker"? If not, a link to a web site for reference might be helpful.
Comment: https://www.bnd.com.au/explore/resource-hub/our-blog/a-guide-to-roller-garage-doors/ simply identifies it as "B&D".  This old ad simply also simply refers to "B&D" https://www.youtube.com/watch?v=qAEgIet0gAI


How do you grow partition on 4 terabyte disk

Question: I used Clonezilla to copy an ext4 1.5 terabyte disk to a 4 terabyte disk.  But when I try to use Gparted to grow the partition to fill the 4 terabyte, it fails. Repeated trials show it only allows me to fill to half the disk (2 terabytes); otherwise I get an error message saying "see details", although there are none.  I suspect that Gparted is operating 32 bit, even though I am running it from a live Ubuntu 64 bit 14.04 media edition DVD.  If Gparted included with 64-bit Ubuntu is limited to 2 terabyte due to 32-bit arithmetic, what else can I use to grow the partition?  Is there a 64-bit Gparted or equivalent?
Comment: MBR partition tables have a 2TB limit. Are you using MBR or GPT?
Comment: It would probably be easier (and arguably safer) to just make more partitions under 2TB each.
Comment: The situation is a data disk (non-bootable) that is running out of space and has to be replaced with a larger one.  It is paired in a RAID array.  To Xen2050: increasing the number of partitions is not an option here.  To muru: I was not aware of the MBR/GPT tradeoff, so thanks to this forum, gparted is off the hook.  I notice that there is a link from @novice about converting MBR to GPT - seems intended for bootable disks, but I will see if it can be interpreted in my context.  Additional help welcomed!
Comment: When it's just about data on a simple EXT4 volume, why don't you just create a GPT partition table on the new drive and a new EXT4 filesystem, then copy all data with `sudo rsync -av` or `sudo cp -a`? If Clonzilla does bitwise copying, it will transfer all the data as is, including cruft and fragmentation, where es copying to a new drive will defragment and ensure that optimal settings are chosen during filesystem creation (like alignment).
Comment: Thanks, @LiveWireBT - This sounds good to me.  Will give it a try.  Better than patching up a clonezilla copy having the wrong kind of partition table.  The newer OSes out there should be using GPT to begin with.  Why not give the installer the choice at least?
Answer: Your filesystem has MBR (Master Boot Record), in MBR maximum partition size is 2TB(tera byte) only, so that's why you are not able to do this.
To make the system capable of this, you need to replace your MBR with GPT (GUID Partition Table). It allows you to create one partition up to 2PB(peta byte).
To replace you can read this link : How can I change/convert a Ubuntu MBR drive to a GPT?
For difference between MBR & GPT go to this link or DuckDuckGo.


How to generate alert on completion of web service with ajax using ASP.NET C#

Question: I am not sure if it is possible to do what I am requesting (have spent some time researching it with no success).
I have an ASP.NET C# page that calls an Ajax function which in turn calls a web service to run a long winded python script. Instead of waiting for the completion of the Ajax call I run the python, show a Toast that the process is running and let the user continue to navigate.
However on the successful completion of the Web service function (post the python run) I would like to alert the user that the process has been complete (irrespective of which page the user has now navigated to). I was interested in calling Toast again from the web service (not sure this is possible), but this is the second prize. The first prize is to send some notification that the process completed successfully (or failed if it did).
Is this even possible or do I need to revert to something like an email on success.
Much appreciated.
Answer: About the only really "easy" way would be if you are "lucky" and are using say webforms, and you have a master page. For each navagation to a page then the master page load events first. Thus, you have a common area/code stub that runs for every web page on your site.
So, when that routine is finished, you could say set some session() value, and your code in the master page could thus check session() each time - and if the process is done (you update some flag/setting in session()), then you could inject via the scriptmanger a toast message. The message would only occur when the user navigates, but you could say include in the master page a iframe - and a timer that checks the session value - say every 5 seconds.
The above is about the only "easy" and practical way. you can also send out (have) push notifications by adopting signalR to your application. The problem with signalR is you do in most cases need "some" JavaScript code in every page - so once again, if you have or are using a master page, then introduction of signalR to your site is a possible (but I do not consider adopting signalR for your site all that great nor easy).
So, when that long running process is done - it would have to call a web method on your site - and that method would update say that session() value, and then your master page could check that session value say every 5 seconds, and if the "done" flag is set, then it could display a message.
SignalR
https://learn.microsoft.com/en-us/aspnet/signalr/overview/getting-started/introduction-to-signalr
I think the timer in a master page (with a iFrame) probably is the least amount of work, as signalR is quite a handful to introduce into a project. But if you don't have a common page (say custom menu bar) or location that  you can "re-check" that status for all web pages in the application, then you have to inroducte some code into every web page - and that's not all of a practial nor great of a idea. So, if you have a master page - then the timer idea, or perhaps chewing on signlR and introducting that into your web site is a road I would consider.
I have a case in which a user hits a page, and in that page I have to fetch some PDF documents, and I display PDF "thumb-nails" for the user. The processing time to load the PDF's, and create the thumb nails? (I only create them one time - save them in a sql server). It takes about 5 seconds - maybe 10 if there are say 6 or more documents.
So, I start a new processor thread to crunch the PDFS. My grid view is in a panel, and I check a session() flag every 1 second. But, once all pdfs thumbs are rendered, then I stop the timer on the form (in that update panel).
Because of the state-less nature of web pages, the only practical "spot" for transferring the done status was session(). If a timer + session() is not practical for you, then you have to bite the bullet and consider adopting signalR for this. For me, it was quick work to use the timer + session() idea, but using signalR is more preferable for such tasks.


Max number of users for free version

Question: Is it possible to build a "free" server (SQL Server Express + Sharepoint Foundation) when the number of concurrent users will be about 20 with the total number of about 100. Both SQL Server and Sharepoint will be running on the same Windows Server 2008 (not sure which edition yet). Will this work? Or I need to consider paid versions?
Comment: I think they bumped SQL Express up to 10gb and you can multiply that ad much as 10x if you implement RBS.
Comment: what deployment will you install? The maximum amount of data you can store in this environment is 4GB.
Answer: This should work. As Rob says, it is only going to be a problem if you put in huge amounts of content (unlikely given the number of users).
However, I wouldn't recommend using RBS (FILESTREAM) to get around the storage limit on SQL Express, other than to get around a particular 2007 upgrade scenario. I just don't think it is worth the trouble and complexity compared to the cost of a SQL Server licence, in my opinion. Can't see it being an issue though with that number of users - you have 10 Gb to play with.
Comment: You will definitley want to monitor your resources closely.  100 concurrent users browsing not much of an issue, 100 users uploading/download docs at the same time you may start to see issues with SQL keeping up.  SQL Express is limited to utilizing only 1 CPU (core), and 1GB RAM.
Comment: He anticipates 20 concurrent users, but a valid point nonetheless.
Answer: Users will definitely not be an issie so you probably only need to be concerned with content volume.  With SharePoint Foundation and SQL 2008 Express you have a 10GB limit but can implement RBS FILESTREAM OR 3rd party RBS provider to increase the amount of content you can manage in the environment...probably upwards of 75-100GB.

Max number of users for free version


Why are compiled Solana programs larger in 1.10.2?

Question: When compiling programs with newer versions of the solana CLI my binary is ~50% larger than before? This is an issue for upgrading old programs built with older version of the CLI. (A program built with 1.9.16 is 1.1mb, the same program built with 1.10.2 is 1.5mb)
Answer: There's no good answer to this unfortunately, except "this can happen".  Typically it's due to additional dependencies that are brought in, or changes to the compiler that result in more code emitted. You can try a later version to see if it reduces the size of the final binary.  And if not, you'll soon be able to increase the size of your program once the ExtendProgram instruction lands: https://github.com/solana-labs/solana/issues/26385


Quick Key Problem HTC G2

Question: I have a Google G2 and for some reason the keyboard has set itself to open apps with almost every letter I push. For instance when I push the letter e on my keyboard it opens the email app. How do I turn this off?
Answer: The slideout keyboard comes with Quick keys which you can assign to quickly open an app or an item when pressed.

Open the slideout keyboard.
Press and hold Shortcut key #1 to assign the first Quick key . Press and hold Shortcut key #2 to assign the second Quick key .
Tap OK
Tap Apps or Shortcuts, and then tap the app or shortcut that you want to assign to the selected Quick key. If you are assigning a shortcut to an item on your phone, follow the screen instructions to proceed.
Press the Quick key you've assigned. The app or item opens.

source: http://www.htc.com/help/www/howto_iframe.aspx?id=18599&type=1&p_id=325
Answer: I had this phone, and I had this problem. Your "Search" key is stuck down -- press it a few times to unstick it.
This model has a feature where you can press search+e to open email. (It is, in fact, fully configurable.) When the search button gets stuck, those shortcuts activate, leading to the behavior you describe.

Quick Key Problem HTC G2


Firefox doesn't save the web page's title as themselves

Question: I want to save web pages, for example, the link http://antwrp.gsfc.nasa.gov/apod/ap080406.html. In other browsers, like Avant or Opera, the web title saves as itself (for example, for the above link, the web title save as "AP OD_ 2008 April 6 - Wisps Surrounding the Horsehead Nebula"), but in Firefox the web title saves as "ap080406". How can I save the web title's as themselves?
Answer: The appropriately named Firefox add-on File Title is exactly what you are looking for.


Serial interfaces of router are used nowadays?

Question: I've heard the use of serial interfaces of router is not so common in the current network environment.
But in some exams like CCNA, you can still see questions including the knowledge of serial interface.
So, I don't know if it is true or not that using serial interfaces is not common.
Comment: Not common does not mean "non-existent". Almost everything is ethernet these days, but you'll still run across the rare T1, T3, and OC-x (as well as DOCSIS cable, xDSL, and cellular) interfaces. P-t-p microwave still exists, but it was always rare.
Comment: Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.
Comment: Are you talking serial network interfaces or serial management interfaces? (the unqualified word "interface" in the context of routing usually refers to a network interface, but it can also refer to any kind of physical data connection or port)
Answer: As Ricky Beam has already written, even though Serial connections might not be common where you live, that doesn't mean they don't exist.
Over 90% of the connections we have in Europe use either Ethernet or xDSL. But in countries like Philippines, Nigeria and Cameroon, we have a lot of Serial connections.
In the end i guess it depends a lot upon where you are and what is available, that is also why Cisco have not ruled this type of connection out of their certifications. I do not know of any database specifying the most used connections based on which country you are located.
Answer: Serial interfaces are commonly used in my work as a Field Engineer. What you've heard is a misconception.
Answer: Long distance Ethernet has grown massively in popularity, because it is cheap, and because it means you don't have to deal with two different technologies for LAN and WAN.
However, building physical infrastructure has both significant economies of scale and significant regulatory implications. So, except for very short distances, it's rarely economical to do it yourself.
What that means is you ultimately have to deal with what the local communications provider(s) will sell you at a price you can afford. If the local communications network is still using oldschool telco equipment and standards then you will have to deal with that.


USB 3G Modem for embedded Linux?

Question: I have to develop an application on embedded Linux which sends data over Internet. I have to choose a USB 3G modem with a SIM card holder, which works successfully or is supported on embedded Linux.
Comment: Do you have any preference for instance?
Comment: I have seen a few from Huawei and one of them is E372. They have not mentioned anything on their website about its support on Linux though!
Answer: Most 3G modems are supported in Linux. I've used several different models, mostly Huawei, on embedded devices using standard Linux packages and libraries - they all  do pretty much the same thing, just with brighter lights or faster stripes. Good starting points are wvdial and pppd.
The main obstacle to overcome is working out the individual methods each provider uses for authentication and access, but this is generally well documented. The Archlinux wiki pages on configuring wvdial and pppd are pretty good:

https://wiki.archlinux.org/index.php/3G_and_GPRS_modems_with_pppd
https://wiki.archlinux.org/index.php/USB_3G_Modem
Comment: Million thanks, I will start working on it very soon and post my prblems if I find any.
Answer: Lots of USB "hotspot" devices exist now ("wingles"), and so do $1 USB wifi adapters that are well supported on linux.  If you can plug both devices in, you get a really no-hassle way to do linux networking, with the bonus that you can easily share it too if you need.
Here's 2 good references for setting up:
http://greyfocus.com/2018/01/wifi-without-networkmanager/ and https://linuxconfig.org/connect-to-wifi-from-the-linux-command-line/

USB 3G Modem for embedded Linux?


Can you explain about this saying of Imam Ali?

Question: Can anyone explain more about this saying of Imam Ali (from Nahjul-balagha):

مَعَ کُلِّ شَیْء لا بِمُقارَنَة، وَ غَیْرُ کُلَّ شَیْء لا بِمُزایَلَة
He is with everything but not in nearness. He is different from
  everything but not in separation.
Comment: @Bleeding Fingers ,you can ask it there!
Comment: [Philosophy.se] would love this question.
Comment: Please mention the source of this saying by [edit]ing the question.
Answer: Simply Allah is everywhere without being somewhere in the way other objects are said to be somewhere, since He has no alike; and Allah is different from the other objects without the objects ever existing without Him, so He is different without being separated from the other objects.
This example may help better understand this. If I am a student in a classroom, the teacher is teaching and I am thinking about my laptop in my room, then physically I am there in the classroom but I am not really there with all my consciousness, so the teacher speaks and I don't hear without pushing my fingers into my ears, my eyes see the teacher but my brain doesn't understand what the eyes see. Physically being somewhere and noticing (توجه) the environment is different. Allah is the Creator, according to Imam Sadiq peace be upon him He creates so how it be possible that He don't know (according to at least some Shia philosophers creation of Allah is continuous so we don't have anything like "creation+maintenance" but only creation from instant to instant, always renewing all the creation). His knowledge about everything thus is fresh, comprehensive and exhaustive, so Him being conscious, having His will and power, being existed and Alive can be considered for everywhere and together with everything that exists, but obviously that doesn't imply that Allah is positioned in every positions. Similarly an example about how is the creation of Allah is that consider your image in a mirror. Your image is an imaginary image, it doesn't exist in reality but still an observer can describe its quality. About the creation of Allah only Allah exists as independent of anything else, but His creation exists only upto His existence, if there is no God there will be no creation, like the image of you in the mirror, it exists as long as you are there in front of the mirror. So the image in the mirror and everything that exist (creatures of Allah) depend on another existences, they are not separated beings but they are different things.
And Allah is the All knower.
Answer: The most important role that Imam Ali (as) has played in Nahj al-Balaghah is the rational depiction of the essence of the divine sanctuary. In a part of the first sermon of Nahj al-Balaghah, he says about the existence of the Almighty:
(کـائـن لاعـن حدث موجود لاعن عدم. مع کل شیء لا بمقارنه و غیر کل شـیء لابـمزایله. فاعل لا بمعنی الحرکات و الآله بصیر اذ لا منظور الـیـه من خلقه).(1)
God exists not by chance; That is, its existence does not precede non-existence, but is eternal, it has no beginning. He exists, but his existence did not arise from non-existence, but he is the same as existence. Is it possible for non-existence to arise from non-existence while there is no contradiction of existence? A community of paradoxes is impossible; Just as its height is impossible. Moreover, (non-existence) can never be the (cause) of creation, because it is the opposite of existence and the negation of existence, and there is no consistency. The Creator of the universe is associated with everything, because deprivation equals extinction. That is, it is associated with everything and always bestows grace It exists and lives. The lamp needs a power plant to illuminate, it also depends on the continuity of the lighting.
(مـع کـل شیء لابمقارنه .(2)
He accompanies everything, but not that he is with him.
(وغـیـر کـل شیء لا بمزایله (3)؛
And other than anything, but not in the form of extinction.)
It is an agent, but not like other actors who need hands and feet to create work; Rather, the will of the truth is equal to the realization of the act. The Qur'an says:
Whenever he wants something and says exist, he will exist without distance.
He is insightful and aware in his works, because his purpose in creation is not personal gain; Rather, he wants the grace of his existence to reach all creatures.
He is one and only, because there is no fixed being to associate with. Anis and Mons are all creatures, but they do not need love and affection.
Do not be afraid of missing something.
PS:

Nahj al-Balaghah, the same.
2.Haman
Haman
Yasin verse 82
Nahj al-Balaghah, Haman
Haman
Haman
Answer: We can answer to this good question after explaining some points:
First, since that the god is infinite and without any boundaries therefore the infinite include finite things. According to imam Ali's Hikmat (widom) the god as infinite being encompasses all other things. Other beings as contingents are dependent in terms of their being to god as necessary being.
Second, god has many different adjectives like above. some adjectives explain negative dimensions like material ,finite etc. and others explain positive dimensions like necessity, perfect being.
When imam ail piece be upon him talks about mogharanah it means that god is not a material thing though it is thing like other things and when we say the god is along with things namely the god as infinite thing include other things. More study see: Ayatollah Javadi AMOLI, ALAVI WISDOM,RESEARCHER:SAEED BAND ALI,ESRA PUBLICATION.QOM IRAN
Comment: Please improve the grammar. And yeah, welcome to [islam.se].
Comment: .its a a good  question  owari.by infinite I mean god has no any quiddity(mahyyah).in other word the  god has no boundary .even there is anything which limit the god. i know that the god is not compound since that we said such a adjectives are negative namely we have to negate them of god.
Comment: Sorry I cannot easily follow you, what do you mean Allah is infinity and infinity include finite things. You have forgotten that Allah is not a compound object or I am missing a point?


Why does a body not move as if it is in free fall when it is on the highest point on a Ferris wheel?

Question:
When the person is at the top of the ferris wheel $mg$ would be greater than $F_{Normal}$. Hence the person would be accelerating downwards. So why does the person move towards the center of the circle as if he was in freefall? Since Newtons second law is "If there is a force acting on the system, the system would move in the direction of the net force in a manner that $F_{net}=ma$" Similarly when he is at the bottom why does he not accelerate upwards since the normal force is > than mg.
Answer:
If there is a force acting on the system, the system would move in the direction of the net force in a manner that $F_{net}=ma$

I think you are confusing motion and acceleration.  Forces determine the acceleration of an object, not the motion at that instant.
The car at the top is accelerating downward, and the car at the bottom is accelerating upward.  But they also have velocity in the sideways direction
Answer: Actually what happens in situations like these is well explained by the term apparent weight. The direction of the force depends on acceleration which in turn depends on the change in velocity. The key point is that the human at the top is not in equilibrium but is in accelerated motion.
Notice that there only two forces acting on the human at the top. There is the gravitational force pulling down and the seat (the normal force) pushing up. These two forces do not have equal magnitude because the human is not in equilibrium but instead accelerating by moving in a circle. The direction of the acceleration at this instant is downward toward the center of the circle.
Using Newton's law :
N - mg = ma(a in y direction) = m(-v^2)/R
N = m(g - v^2/R)
This says that at the top, your apparent weight will be lower than your actual weight by some amount that depends on both the size of the wheel and the angular velocity.
Answer: The body is going round in a circle and hence undergoing centripetal acceleration produced by the net force due to the two forces acting on the body of mass $m$, the weight of the body $mg$ and the normal reaction of the seat on the body $F_{\rm normal}$.
At the top assuming down is positive and using Newton's second law $mg -F_{\rm normal, top} =\dfrac{mv_{\rm top}^2}{R}$ where $v_{\rm top}$ is the speed of body at the top of the Ferris wheel and $R$ the radius of the Ferris wheel.
Notice that if the Ferris wheel roared fast enough the normal force could be zero or even acting downwards, the normal force in the case being provided by the seat belt.
At the bottom with up as positive, $F_{\rm normal, bottom}-mg =\dfrac{mv_{\rm bottom}^2}{R}$


What are some projects that have taken advantage of Bitcoin's taproot upgrade so far?

Question: Are there any projects as of 2022 May that have taken advantage of Bitcoin's taproot upgrade? I'm still trying to understand what can be built with this taproot feature.
Answer: Projects that support paying or receiving to P2TR addresses are tracked here.
A non-exhaustive list of projects that are working on doing more interesting things taking advantage of Taproot block space savings and improved privacy: Bitcoin Core, rust-bitcoin, btcd, secp256k1-zkp (MuSig2 and FROST), lnd/Taro, Taproot wallets (e.g. TapWallet), Taproot scripting tooling (e.g. btcdeb, Script Wizard). There has been a lot of discussion on the lightning-dev mailing list and elsewhere on how the Lightning Network protocol could upgrade to take advantage of Taproot but at the time of writing that is still at the discussion phase.
Some additional Taproot use cases are listed here.

I'm still trying to understand what can be built with this taproot feature.

For the most part Taproot doesn't support any new functionality (there were no new opcodes added with completely new functionality, just a replacement for OP_CHECKMULTISIG and a tweak to undefined opcodes), what you could do before Taproot you can do after Taproot just with block space savings and improved privacy.
Answer: Citadel:

Bitcoin, LN & RGB wallet runtime supporting Taproot, miniscript,
descriptors, multisigs, PSBTs


Can you make a recharging Tattoo Spell?

Question: Is it possible to make a spell tattoo from the Craft Spell Tattoo feat that is permanently reusable? That is, a tattoo that recharges and can be cast (e.g.) 1/day?
Answer: Custom Magic Item Creation
Following Magic Item Creation Rules, this would be pretty simple and straight forward.
How I Would Do It (Opinion)
Let's break it down.
Base Cost: From the first entry under Spell Effect (Command word), we can see that the base cost should be Spell level x Caster level x 1,800 gp.
Modifications: For a tattoo like the one you mentioned, it would be a slot-less item, which adds the "No Space Limitation" modification, which doubles the price. And, as you suggested, using X times per day, you divide by (5/X), where the higher value for X results in a higher price. This second modification is taken from the "Charges Per Day" row under Special.
Comment: Thanks, this was what I was looking for, I was having a hard time finding it and understanding it.
Comment: No problem. To my knowledge, there's nothing about Magic Item Creation that would prevent you from making a tattoo, though you'd probably still need the Craft Spell Tattoo feat.

Can you make a recharging Tattoo Spell?


Isn't a tenuto marking redundant?

Question: If a tenuto mark means to "hold for the entire value of the note" as it's often defined, isn't this redundant?  Aren't we expected to hold notes for their entire value anyway?  So what is a tenuto mark truly telling us to do differently?
Comment: I'll add that the tenuto marking does disambiguate and emphasize that the note should be played for its full length and not be treated as *simile* with the articulations of notes in similar motives. I once transcribed some of Elgar's Pomp and Circumstance Marches from the original sheet music, and I saw several sections where orchestras had interpreted the articulations as similar to earlier sections with articulation markings, despite the lack of articulation markings on these later sections' notes and the lack of *simile* indications.
Comment: This seems like a duplicate of https://music.stackexchange.com/questions/31365/so-what-does-this-tenuto-mark-mean-in-bernsteins-piano-music and https://music.stackexchange.com/questions/17204/what-is-the-proper-name-of-the-dash-symbol-over-a-note-and-how-to-play-it.
Comment: On bowed strings/woodwind/brass the performer can change the speed of attack used for tenuto accents. But if you're performing on a piano you don't have as much control over the speed of attack - perhaps all you can change is the length and volume.
Comment: @Dekkadeci  there is overlap but the answers here IMHO are more detailed and easier to understand than the answers there.  I wonder if we can mark those others as "the duplicate" :-)
Comment: _"Aren't we expected to hold notes for their entire value anyway?"_ Nope!
Comment: Hi PianoGirl. Welcome to MP&T SE. There are a lot of conventions on how to read music score. For instance, phrase-marked notes may overlap, or playing a repeated section for the second time is (can be) an invitation to change how that music is articulated. Tenuto is making doubly-sure that notes which may be less than full value, for instance, because the player is reaching for a distant note, will keep it's full value. It's a statement of the composer's intention.
Answer: Tenuto markings often show that a note has extra weight to it. Notes with these markings would not have a sharp/edgy beginning like an accented note, but they are often slightly louder than the notes without tenuto markings. They are also useful in helping to communicate the mood of a piece, as they are more often used in slower, heavier, more somber pieces than in pieces that are quick, light, and cheerful.
Answer: There is more to a tenuto marking than that.  It can mean slightly different things in different contexts.  For example, if there is just one note in a phrase with a tenuto marking, then it would suggest that that note is more emphasised than the others.  If you had a row of the same notes, all with tenuto markings, then you would probably play each one with a slight emphasis and therefore making them sound more separated than fully legato.  If you had a row of staccato notes and then one that wasn't, you might put a tenuto marking on that one as a precaution.  I hope that shows that the tenuto marking is not redundant.
Answer: This post is already three years old, but the question "Aren't we expected to hold notes for their entire value anyway?" deserves a more detailed answer than just the simple "No" in one of the comments.
At least in pre-romantic music, notes were expected to be separated by gaps or pauses. IIRC, G.D. Türk (see edit below for correction) gave the rule that the gaps should take half the note values. The pauses are stolen from the length at the end of the notes. This is called articulation, and varying the lengths of these pauses is one of the most important means in music performing. It is mostly used to distinguish good and bad notes in the musical metre, but can also be used for phrasing: a slur connecting two notes, e.g., often indicates that the second note is to be shortened, thereby creating a sighing effect.
The other important means when performing music is agogics, which means altering the length (including the gap introduced by articulation) of the notes. Quantz (ca. 1750) gave the rule that in chains of the shortest note value in a piece the first of each group (falling on a good time in the metre) should be prolonged and the subsequent note(s) shortened. This is nowadays mostly associated with French baroque music and 20th century Jazz, but Quantz made it clear that it applied to all music.
On instruments without dynamics (organ, harpsichord), articulation and agogics are the only ways to make real music from mere notes. On instruments with dynamics (lute, piano, violin) loudness (dynamics) is a third method, but this does not mean that articulation and agogics should not be used on these instruments.
Edit: Just had a chance to lookup the citation in Donington's "The Interpretation of Early Music" (quite old, but still a very useful collection): It was not Türk, but C.P.E. Bach who wrote 1753: "Notes which are neither detached, slurred nor fully sustained are sounded for half their value." G.D. Türk wrote 1804: "If Notes are to be played in the common way; that is to say neither staccato nor legato, the fingers must be lifted a little sooner than the Time of the length of the Note is expired." The recommended amount of "default articulatuon" thus varied, and might also depend on the instrument: if the sound decays much slower (like on a modern piano compared to a harpsichord or a pianoforte), a stronger articulation might sound less natural.
Comment: Quants isn't describing _notes inégales._  Otherwise, this is just the answer I was thinking of adding when I opened this question just now.
Answer: A tenuto marking is somewhat of an accent mark for note length, but to a lesser degree. While a tenuto isn't an outright fermata, it means to put more emphasis on a note. Tenutos used in tempo rubato (free tempo) usually mean to not play the note faster than usual.
A tenuto is somewhat like a swim coach telling you to push hard and swim as fast as you can during a swim meet—you're going to do it anyways, but his reminder serves as extra emphasis.
Answer: Articulation of any kind is never assumed. It is always based on the musical context, what is appropriate for that particular moment. When a composer specifically adds an articulation then he is specifying what he has in mind at that moment. A tenuto merely clarifies that "these notes should be full length", not something else the performer may have had in mind. There is no accent intended, no extra weight implied, no mood, no particular emphasis, etc. If any of those things do happen, it is in no way a result of the tenuto marking, but some other context of the music.
Answer: This is, in a way, not an instruction how to play the note but how to make it appear to the listener.  Without accent markings, there are some freedoms in articulation, like doing things leggiero.  On an instrument with continuous tone control, you wouldn't interrupt tone control (like breath or bellows pressure) for successive leggiero notes but would distinctly separate them (tongueing, alternating fingers on the same key with nary an interruption) and maintain the phrasing.
The notes are not accented on their onset but accent the progress of sound, without merging them into one another like legato would.

Isn't a tenuto marking redundant?