Questions about loyalty rewards for playing previous borderlands?

Question: How do i get loyalty reward? Do i need to have both savegame or i just need 1 savegame to get loyalty reward? Right now i just has borderlands 1 savegame
Is there any different reward from BL 1 or 2 save game ?
Answer: The rewards depend on what kind and how many previous games you have.
If you have a borderlands 1 savestate, you get a special weapon and a special skin, also a bunch of moonstones.
With a borderlands 2 savestate, you can be happy about a special weapon, another special skin, a few moonstones and badass points.
When you got both, you get everything, plus even more moonstones.
Comment: Does the save state need to be from a particular part of the game? Like "you need to have finished the game"? or could you even have a save state where you just entered claptrap's cave in BL2?
Comment: Thanks for amswering my question. I just found my BL 2 savegame. And i just about to copy to my documents so BL Pre Sequel can detect. But its possible to get bonus if i played the game almost half the story? Or d i need to do new game?
And sorry for my english :)


How do I add a custom PriceFeed from the SDEX exchange

Question: On the getting-started page I see sdex listed as an out of the box exchange integration. Is that only used for buying/selling or is there a way to use sdex instead of Kraken to get token price info?
Thanks
Answer: Currently you can only place orders on SDEX, but you can fetch data from Kraken, Binance, Poloniex, and Bittrex.

It should be relatively very easy for you to create a new price feed that supports this.
Take a look at the implementation for fixedFeed, which is only a few lines.
Your implementation would fetch the orderbook for your configured SDEX market and use that data to come up with a centerPrice that is returned in the PriceFeed's GetPrice() method.

Once you have your new priceFeed implementation, you can add it to the list in the PriceFeed's MakePriceFeed() factory method.
Answer: All the current strategies only use the SDEX for buying and selling, and no function is yet present to actually pull the relevant SDEX orderbook.
I'm working on a new strategy that will use the SDEX orderbook data, no ETA yet.


1)Se lo pierde . 2) se lo pregunto

Question: I have 2 questions ;
The first one is in relation to a boyfriend and girlfriend break-up. In this case ,I mean to express that after the break-up someone says,''it is his loss'' or'' it is he who will miss out''. The translation I think is '' se lo pierde''.
Is this because the infinitive is '' perderse'' in which case I never understand when to use these types of verbs beyond the obvious reflexive forms .
Or is it more to do with object pronouns where ''le'' and ''lo'' cannot follow each other and then it has to be''se''? Then,I think I understand this.
2)
''se lo pregunto'' is a similar question. I want to say,'' I ask you''. Therefore, is it because the verb is ''preguntarse'' or is it to do with direct object pronouns? I think this is using ''usted'' rather than ''lo te pregunto''.
Comment: perderse (reflexive) versus preguntar algo a alguien. Bear in mind that when you say: preguntarle [a el or a ella or a usted] algo, there are two pronouns, one direct and one indirect: le and lo: ask you or him or her about it. But: you can't have le lo in Spanish. **The le becomes se** referring to whom you are asking: Se lo pregunto [a él o ella o usted]. That is not reflexive....It is an indirect object.
Answer: Whenever "se" is used with another pronoun, this may be due to one of two reasons:

The pronominal nature of the verb.

The simultaneous appearance of a pronominal direct and a pronominal indirect object.

The case of:

Se lo pierde

corresponds to (1), because the verb is "perderse (algo o a alguien)".
With other persons, other pronouns will be used instead of "se":

Me lo pierdo.
Te lo pierdes.
Nos lo perdemos.
Os lo perdéis.

Instead, the case of:

Se lo pregunto

corresponds to (2). "Se" refers to the person being asked, and "lo", to the thing asked. For example:

Voy a preguntar el nombre (DO) a él (IO).

LO voy a preguntar (el nombre, DO).

LE voy a preguntar (a él, IO).

When both pronouns coexist, we cannot say *Le lo voy a preguntar, and "le" is replaced with "se":

Se lo voy a preguntar.

"Se" always refers to a third person, or to second person "usted", which behaves like a third person pronoun.
With other persons, other pronouns will be used:

Te lo voy a preguntar.

Os lo voy a preguntar.

Me lo vas a preguntar.

Nos lo van a preguntar.
Comment: @Lambie What I meant to say by "overlapping" is that two pronominal objects are being used simultaneously, and this results in "le" having to change to "se". I will change the wording to avoid confusions. Thank you for your observation.
Comment: @Lambie It is sometimes hard to explain Spanish grammar concepts in English grammar terms. My point is that objects can be nominal (noun phrases) or pronominal (pronouns).
Comment: Se lo pregunto is not "overlapping." There is an indirect and direct object following each other where the le become se because you can't have le and lo together. Learners often do not know this.
Comment: I get it but we would say in English, a **direct and an indirect object** next to each other when they give rise to le lo or le la. We would never say "pronominal objects".
Comment: I disagree. Objects can be direct or indirect in English, or you can have a reflexive pronoun.  I explained it perfectly simply in my comment under the question. It is very frustrating to try and explain what we use and do not use in English and again getting a kind of "Spanglish" comment. It's like you want to avoid my point. FIne, you have every right to do that. There is nothing more for me to say.
Answer:
It is an idiom:

Ella se lo pierde =

It's worse for her. It's her loss.
Too bad for her. It's her loss.

Él se lo pierde =

It's worse for him. It's his loss.
Too bad for him. It's his loss.

Por eso se lo pregunto(a usted) = That's why I'm asking you.
(That's a formal way of saying that)

Por eso te pregunto (eso) = That's why I'm asking you.

Por eso te (lo) pregunto = That's why I'm asking you.

I asked her/him. = Le pregunté(Sobre eso a él/ella)
Le pregunté a ella/él sobre eso = I asked her/him about that. (Either redundant or to distinguish her from everyone else)

Se lo pregunté/Se lo estuve preguntando(I was asking him/her about that)
Se lo pregunté a ella(Either redundant or to distinguish her from everyone else)
Se lo pregunté a él(Either redundant or to distinguish him from everyone else)

I asked you/I was asking you about that/I was asking it to you =

Te pregunté (eso)/Te estuve preguntando(eso)
Te (lo) pregunté/Te (lo) estuve preguntando/Estuve preguntándotelo.
Te (lo) pregunté a ti(Either redundant or to distinguish him/her from everyone else)

I was wondering that=

Me lo estuve preguntando.
Me preguntaba eso.
Me lo estaba preguntando.
Me estaba preguntando eso.
Estaba preguntándome eso
Estaba preguntándomelo.
Estuve preguntándomelo.

1)Se lo pierde . 2) se lo pregunto


Smallest 3-category not equivalent to a strict 3-category

Question: For modular lattices there is a canonical example of the "smallest" non-modular lattice, $\mathbf N_5$. Is there a similar example for 3-categories which are not equivalent to any strict 3-category? I have read so many times that there do exist such 3-categories but I have never seen an explicit example of one.
Answer: The homotopy $3$-groupoid of $S^2$ is not equivalent to a strict $3$-category. While it may or may not be the strictly smallest weak 3-category with this property, this seems to be the standard example.
This was, as far as I know, first proven by Clemens Berger. For a reference, see Carlos T. Simpson's book "Homotopy theory of higher categories", Corollary I.4.3.3. and section I.4.4. in this draft.
Answer: Simply connected 3-groupoids $X$ have two homotopy groups $\pi_2(X), \pi_3(X)$, and are classified by this pair of homotopy groups together with a $k$-invariant, namely a cohomology class in $H^4(B^2 \pi_2, \pi_3)$. It turns out that $X$ is strictifiable iff the $k$-invariant vanishes iff $X$ is just the product $B^2 \pi_2 \times B^3 \pi_3$.
The case of the fundamental $3$-groupoid of $S^2$ corresponds to $\pi_2 = \pi_3 = \mathbb{Z}$ with $k$-invariant the element of
$$H^4(B^2 \pi_2, \pi_3) \cong H^4(\mathbb{CP}^{\infty}, \mathbb{Z}) \cong \mathbb{Z}$$
which as a cohomology operation $H^2(-, \mathbb{Z}) \to H^4(-, \mathbb{Z})$ is just the cup square. A "smaller" example is to take $\pi_2 = \pi_3 = \mathbb{Z}_2$ with $k$-invariant the cup square $H^2(-, \mathbb{Z}_2) \to H^4(-, \mathbb{Z}_2)$.
Comment: Is there a way to understand this without any knowledge of homological algebra? Maybe a finite presentation? Just a guess but, your "smaller" example has 1 object $x$, 1 arrow $id_x = a $, 2 2-arrows $id_a$ and $b$ (with $a^2 = id_b$),  and... 8 3-arrows? (2 in each of $hom(id_a, id_a)$, $hom(b,b)$, $hom(b,id_a)$, $hom(id_a,b)$ )? Also, what is a "cup square"? I can't find any reference for this.
Comment: @Justaskin_: "cup square" refers to the squaring operation $x \mapsto x^2$ in a cohomology ring (whose multiplication is called the "cup product"). You're not going to get very far studying 3-groupoids without knowing any homological algebra... but in any case, you can think about simply connected 3-groupoids as "braided 2-groups": explicitly, they can be modeled as braided monoidal groupoids in which every object is invertible. Strictness corresponds to replacing "braided" with "symmetric" (or something like that; maybe it's even worse than this).
Comment: The point here is that in this case the interesting data of the 3-groupoid is not in the morphisms but in the coherence data being required on various compositions, which in the braided 2-group model corresponds to the braiding. For strict 3-groupoids you replace these coherences with identities and things are much less interesting.


What is the definition of a polybasic cleavage site?

Question: I keep coming across the term "polybasic cleavage site" which is implicated in increasing the virulence of many viruses, but I'm struggling to find a definition. Is it just a sequence of amino acids where more than one has a basic side chain? I'd also love to know why it is so important to the function of a virus.
Answer: I would define a "polybasic cleavage site" as:

A region on a protein consisting of several basic amino acids (generally arginine (R) and lysine (K), rather than histidine) that determines the substrate specificity of certain classes of proteases for that protein.

It can also be regarded as a recognition site for the enzyme.
The relevance of this to the virulence of some viruses is as follows. Many RNA viruses are translated into one or more polyproteins that are subsequently cleaved proteolytically at specific sites to generate further proteins. In certain instances these sites are 'polybasic', and the products generated by the cleavage of such sites play a role in the virulence of viruses.
This is nicely illustrated by a paper by Nao et al. in mBio on the mutation of haemagglutinin (HA) cleavage site of Avian Influenza Virus, where increasing the number of basic amino acids increased the virulence. I included an illustrative figure from that publication.

HA cleavage site sequences of the ShimH5 virus strain and its variants passaged in chickens
The current (2021) interest in polybasic cleavage sites no doubt relates to the presence of such a site (PRRAR) at the S1/S2 junction in the spike protein of SARS-CoV-2 — see, for example, this paper by Peacock et al. in Nature Microbiology.
Answer: A polybasic cleavage site is a cleavage site consisting of polybasic amino acids. An acid is polybasic when it is able to donate more than one proton in aqueous solution. In a titration curve, polybasic acids show as many equivalence points as they are poly.
https://www.w3spoint.com/ionization-of-a-polybasic-acid
Comment: Unfortunately, your logical analysis of the word  —  a site with a single acidic amino acid residue with multiple ionizations — is incorrect because no such amino acids exist in proteins, and, as I indicated in my comment on the question, the usage is for a site with many basic amino acid residues.
Comment: You are right thank you for pointing this out


Word for doing something specifically to undermine status quo

Question: Is there a word which means to do something specifically to undermine the status quo? Perhaps in a political context?
Answer:
subvert  [verb]
undermine the power and authority of (an established system or
  institution)
an attempt to subvert democratic government

[ODO]
Answer: Revolt, according to Cambridge Dictionary:

If a large number of people revolt, they refuse to be controlled or ruled, and take action against authority, often violent action.

One of their examples (quoted from the same page):

Californians may be ready to revolt against broad cuts in government services.

Attribution: "Revolt Meaning in the Cambridge English Dictionary." Cambridge Dictionary. Accessed March 30, 2018. https://dictionary.cambridge.org/dictionary/english/revolt.
Comment: we got skunked on this one!
Comment: no votes for either of our answers ... yet
Answer: game-changer  EOLD

An event, idea, or procedure that effects a significant shift in the
  current way of doing or thinking about something. 'a potential game
  changer that could revitalize the entire US aerospace industry'

Although probably originally a sports phrase, it's used in politics and business.
As for a person who shakes things up, gadfly:

A gadfly is a person who interferes with the status quo of a society
  or community by posing novel, potently upsetting questions, usually
  directed at authorities. The term is originally associated with the
  ancient Greek philosopher Socrates, in his defense when on trial for
  his life. (Wikipedia, "social gadfly")
Comment: I can see _gadfly_, but I don't think that _game-changer_ implies intent in the way that OP needs.
Answer: The idiom rock the boat means "to do or say something that may upset the status quo."
Answer: kibosh TFD and Word of the Day MW Dictionary Podcast
(Related to kibosh: put the kibosh on)

a check, end, or stop.

As in (without a sample sentence):

He put the kibosh/ is trying to kibosh our long standing X.
Answer: I believe the word is sabotage. And I like the French pronunciation.

SABOTAGE [chapter heading] The title we have prefixed seems to mean "scamping work." It is a device which, we are told, has been adopted by certain French workpeople as a substitute for striking. The workman, in other words, purposes to remain on and to do his work badly, so as to annoy his employer's customers and cause loss to his employer. ["The Liberty Review," January 1907]
You may believe that sabotage is murder, and so forth, but it is not so at all. Sabotage means giving back to the bosses what they give to us. Sabotage consists in going slow with the process of production when the bosses go slow with the same process in regard to wages. [Arturo M. Giovannitti, quoted in report of the Sagamore Sociological Conference, June 1907]
In English, "malicious mischief" would appear to be the nearest explicit definition of "sabotage," which is so much more expressive as to be likely of adoption into all languages spoken by nations suffering from this new force in industry and morals. Sabotage has a flavor which is unmistakable even to persons knowing little slang and no French .... ["Century Magazine," November 1910]


Destroy old Apple IDs from my iPhone

Question: I created three Apple IDs on my iPhone. I have signed out of all three IDs one by one. However now I am not able to create a new Apple ID on my iPhone.
Comment: Why did you need to create three, and why do you need to create more? You only need one Apple ID.
Comment: For some strange reason there is a limit to how many can be _created_ per device.  You might be able to create via appleid.apple.com but there seems to be some sort of limit there as well, that is less easy to define.  Why are you creating so many?
Comment: @Tyson Given that any one person only needs one (maybe if you twisted my arm I could get on board with needing two), why would it be _strange_ that there's a limit on how many can be created?
Comment: Can you add some details about why you want to create a new Apple ID in the first place? If it is "just" a case of forgotten password there are other ways to resolve that.
Answer:
You cannot 'destroy' Apple IDs, they last forever.
You only need one ID. You can change the associated email address if needed.
The ID used to set up the phone or to download any software is the only one that can ever update or restore it.
Giving someone else your ID & password details is a security nightmare & foolish in the extreme - open to abuse at any time in the future.
Answer: I suggest creating Apple ID via web page instead of iPhone. The sign in page:
https://discussions.apple.com/login.jspa (click 'create one now' on the right).
P.S. If you should sign out all the apps associated with Apple ID, including iMessages, iTunes Store, App Store, etc...

Destroy old Apple IDs from my iPhone


Kashering with a potted plant

Question: On Friday, my grandmother made a comment about kashering a knife by sticking it in a potted plant (with very loose soil), something which will not kasher anything. What is the origin of this bubbe-meiße (old-wives' tale)?
Comment: My grandparents were "semi" yekkeh. I would sometimes see their famous "knife and fork" plants in the living room. NOW, I know why the cholent sometimes tasted gritty ;-)
Comment: I love the faux-German spelling of "meiße".
Comment: 10 times in the ground is called Neitzah ,it can be found in a few places in Yoreh Deah,not sure what she means though or how she does it
Comment: This is not a bubbe meiße even if most people today don't know about it.
Comment: @Ypnypn, I'm a yekke and Yiddish is a Germanic language, thus I try to spell it as German, rather than some YIVO narischkeit
Answer: You might be referring to the practice of thrusting a knife into dirt 10 times as part of kashering. I will cut and paste some posts I found on the subject from http://www.imamother.com/forum/viewtopic.php?p=248118

The halacha is, if you treif up a knife you can't just boil it in water like you would do any other kind of silverware, you have to stick it into the ground (any firm soil) ten times. This is b/c a knife is used for cutting which means you use more pressure with it than other silverware, and therefore in order to kasher it you have to also use pressure and stick it in the ground.
It follows the principle of "k'boiloi kach poltoi" - however the taste got absorbed into the vessel, you have to use the same method to remove it.
Forgot to mention that this only applies to knives that are made of one piece. Not the ones with a plastic handle which AFAIK CANNOT be kashered. Please correct me if I'm wrong
my mistake....I don't know if it's a lechatchila, but yes, the knife can be plunged in like 10x. My husband was told that nowadays they suggest steel wool because of it's abrasiveness.
The rabbi who teaches a halacha class at our shul mentioned this. He said it was done to kasher a knife if you had only one knife to use for both milchig and fleishig, and no other way to kasher it. It had to be driven into hard ground several times in order to create friction to generate heat.

None of the posts on that website provides a source.
The Star-k website has the following statement:
"Sticking utensils in soil is generally not an effective way of kashering. (There is only one case where it is effective and so that is why some think that this method works.)"
[but I can't find anywhere on their website where they detail the one case]
This site details the practice at the beginning:
"However, when a knife or other utensil is used to cut, chop, grate, or grind a non-kosher food, a residue of that non-kosher food remains on the knife even after the knife is "cleaned".1  This principle, known as duchka d'sakinah, is discussed in the Gemara and Shulchan Aruch,2 where it states that the knife may only be used for kosher food if it either undergoes a process known as נעיצה   or is filed down (i.e. sharpened).  נעיצה   involves thrusting the knife into semi-solid earth 10 times, and it is generally understood that this process is effective, because the earth serves as an abrasive cleaner for the knife's blade.
1 See, for example, Toras Chattas 23:7.
2 See Gemara, Avodah Zara 75b & 76b, and Shulchan Aruch 10:1, 96:1 & 121:7."
Answer: The Simlah Chadasha (10 "יתר דיני סכין"), discusses different ways to mess up a knife and how to fix them. If someone slaughters a טריפה1 (an animal that has certain physical deformities, such that it would not live 12 months), the knife must be cleaned (via rinsing הדחה or rubbing קינוח) from the fats of the טריפה.
But, if one killed three טריפות in a row, without a good שחיטה or הדחה\קינוח in the middle, then that knife needs נעיצה in hard ground to be kashered (10:13). הדחה\קינוח do not help for this case.
If there were three in a row with כשרות in between, then נעיצה is required as a לכתחילה (see above).
One טריפה by itself does not require נעיצה, because the שמנונית איסור (fatty leftovers of forbidden food [= טריפה]) has not really gotten stuck to the knife from just one time ("משום דלא אידבד איסורא בהאי סכין וכו," there 12) -- that only happens on three.
This case is the only case that נעיצה is needed, and, indeed, helps. Read through סימן י there, and this procedure is mentioned only by the knife that was used for three טריפות (as in 13 and 92), or to say that it doesn't work (5, 7, and 11; maybe more).

Sticking it into the ground ten times means sticking it into the ground ten times (there, 7). This does not mean sticking it into the ground nine times, nor does it mean sticking it into the ground once and leaving it there (leaving it in the ground does nothing -- we need abrasive force to scrape hardened [invisible to the naked eye] fat from the knife).
The ground should be hard (5), virgin soil that was not disturbed.

1 While it is not explicit in the text of the Simla Chadasha, I asked my rebbi and he told me that the same would also apply to neveila as well. [If you can source this to another ספר הלכה, please leave a comment below!]
2 That is a case where one used a knife that was used (for a long time) by a non-Jewish slaughterer -- one may assume that it was used for many טריפות (and, לכאורה, also נבילות as per the above footnote) and thus requires נעיצה.
Answer: It's called נעיצה, and all the sources I've seen have specified that the ground must be hard when you thrust the knife in. I don't know the exact origin, and this is not an exhaustive list, but it is mentioned by the Rambam (maachalot asurot 6:20 and 17:7), and followed by the Shulchan aruch (YD 121:7, YD 10:1, ), and the Rema (YD 89:4, YD 69:20) in certain circumstances. In other words, it's actually not totally a bubba-meisa, although in practice it is rare.
My guess on why it's so uncommon today (and this paragraph is purely speculation so please treat it as such), is that in times when running water was harder to obtain neitzah was relied upon more because the ground was more convenient than a well. Nowadays with the invention of indoor plumbing and faucets, water is easier to obtain so people use boiling water in cases where either neitzah or boiling water is an option.
Comment: The source I quoted in my answer was very clear on the point that when you need נעיצה, that הדחה קינוח **OR הגעלה** would not work.......
Comment: re:¶2 I suspect that there may also be an element of uselessness, as @Danno pointed out, it only works on items which have one-piece construction.
Comment: Also, knives are cheap, so you can have dedicated ones for different purposes.
Comment: @Shokhet - I assume you're referring to my speculation in part 2. I realize there are some situations in which either will suffice, and some in which only one or the other is needed. That's why I added "in cases where either neitzah or boiling water is an option" to the end. If in all the cases where hadacha was acceptable people started doing hadacha, that would lower the overall number of times people saw neitzah, and make it rarer. I didn't say it was never done, it just seems to be fairly rare and many (like the questioner) haven't heard of it.
Comment: @Bachrach44 Which cases are those, that "either will suffice"? [not attacking, just curious]
Comment: @Shokhet The Rambam [here](http://www.sefaria.org/Mishneh_Torah,_Forbidden_Foods.17.7) has a situation where one or the other is needed. Also many of the other places (for example, Rema in YD 69:20), call for washing as the alternative, which would still require water. For the record, I want to clearly state that I'm not stating any halacha l'maaseh here - I'm only quoting specific opinions. I've only just started learning basar v'chalav, so I couldn't give halacha l'maaseh even if I wanted to.

Kashering with a potted plant


003V SOT23-6 What is this component

Question: This IC produces 29.6 kHz square wave and there is no external components. What it can be? I looked at all codes and I can't find it.
Comment: show a bigger picture showing components around it.
Comment: user2815122 - FYI these are the current "[Component Identification Question Guidelines](https://electronics.meta.stackexchange.com/q/6710)". The more information you can supply from that list, the better the chances of identification. Thanks.
Comment: it going to hef4538 as a clock signal
Answer: It looks like a PIC10F200. The datasheet describes the marking code as having two characters of 'customer specific information', and two of 'alphanumeric traceability code', but in practice the first two digits appear to be the last two digits of the part number ('00' for PIC10F200) and last two are 'random'.

Here are some vendors' images of what purport to be a PIC10F200.
Answer: Based on the limited information you've given, it very likely a programmable timer IC.  Possibly a LTC6906, based on the package and frequency you've listed (10kHz to 1MHz).
See if there is a resistor connected to one of the pins, and if you let us know the pin names I can find the exact part or at least a drop in. Specifically let me know pins tied to Vcc, Gnd, signal out, and the pin with a resistor on it. Also what the Vcc for the part is.

003V SOT23-6 What is this component


PHP Gmail API doesn't fetch emails

Question: I use the PHP google api with OAuth2.
ALL the process of the token procees
has been successfuly completed.
I use the scopes:
$a_scopes = array(
                  Google_Service_Oauth2::USERINFO_EMAIL,
                  Google_Service_Oauth2::PLUS_ME,
                  'https://mail.google.com/mail/feed/atom'
                 );

$this->client->setScopes($a_scopes);

I use the code to retrieve the emails:
$plus = new Google_Service_Plus($this->client);
$person = $plus->people->get('me');
$user = $person->getEmails();

echo("
");var_dump($user);die("
");

The result:
array(1) {
   [0]=>
   object(Google_Service_Plus_PersonEmails)#29 (4) {
      ["type"]=>
      string(7) "account"
      ["value"]=>
      string(17) <My Email>
      ["modelData":protected]=>
          array(0) {
          }
      ["processed":protected]=>
          array(0) {
          }
   }
}

Answer: I don't think that the atom feed is a defined scope for the API. The documentation only defines the basic: Modify, ReadOnly and Compose scopes. The Atom Feed only shows you unread messages, and even then only shows snippets of the message.
To fix your issue you need to define your scope as one of those defined by the Gmail API

PHP Gmail API doesn't fetch emails


Blender 2.8 crashes while compiling scene

Question: enter link description hereI have a new Mac Book Pro - with 32 gig of ram plenty of disk space.  Every time I try to render a scene using cycles I get through 5-30 frames and blender crashes.  Any thoughts or help would be really appreciated.
Comment: Share your blend file
Comment: I added a link above.  This blend file is about as simple as they come but the render still crashes.  I never had this problem in 2.79.  i9 processor 32 gig of ram.  I have reduced as many settings as I can think of but the scene always stops along the way.
Comment: @RSchuler the blend link you shared is not publicly accessible.
Answer: This sort of situation is why it is often recommended that you render to an image sequence rather than to a video file. Once all frames have been rendered you can quickly convert the image sequence into a video format.
If blender crashes after 20 frames, then render 15 frames at a time. You could also use a script that will repeatedly start blender and render one (or 10) frame each time.
In the output panel you can enable placeholders and disable overwrite to get blender to only render frames that haven't been rendered yet, note that crashing in the middle of a render will leave the placeholder. This should allow it to continue rendering from where it was when it crashed.
When you have a blend file that causes blender to crash, consider submitting a bug report so that the developers can find why and find a fix for the next release.
Comment: Just for the sake of clarity.  The output is rendered to an image sequence all out is PNG files.


some properties of consecutive primes

Question: If $p_1$ and $p_2$ are two odd consecutive primes and n is their midpoint, then $p_1p_2$ is the largest odd multiple of $p_1$ not exceeding $n^2$.
This sounds obvious, but I still have problem to prove it.
Comment: What is the "midpoint"? Their average, $\tfrac{p_1+p_2}2$?
Comment: yes it is the average.
Comment: What we have to prove is that  (_1_): $\ p_1p_2\le n^2$ (which follows from geometric and arithmetic means), and that (_2_): $\ p_1(p_2+2)> n^2$, where $n=\frac{p_1+p_2}2$, i.e. that
$$4p_1(p_2+2)\ > \ (p_1+p_2)^2$$
which is equivalent to $8p_1>(p_2-p_1)^2$.
Comment: The first point (1) is straightforward. What we need to prove is a more general aspect of (2): We need to show that $p_1(p_2+2a) > n^2$ for any positive odd integer $a$.
Answer: Continuing Peter's comment, Andrica's conjecture also states that
$$p_{n+1}-p_n=\left(\sqrt{p_{n+1}}-\sqrt{p_n}\right)\left(\sqrt{p_{n+1}}+\sqrt{p_n}\right)<\sqrt{p_{n+1}}+\sqrt{p_n}<2\sqrt{p_n}+1$$
which is better than
$$p_{n+1}-p_n<2\sqrt{2p_n}$$
More than that, it is easy to prove a particular case of Andrica's conjecture, if there are no perfect squares between $p_n$ and $p_{n+1}$ then $\sqrt{p_{n+1}}-\sqrt{p_{n}}<1$
$$k^2<p_n<p_{n+1}<(k+1)^2 \Rightarrow k<\sqrt{p_n}<\sqrt{p_{n+1}}<k+1$$
and the result follows. For example $(2,3)$, $(5,7)$, $(11,13)$, $(17,19)$, $(19,23)$ ...
Additionally, "on average", Andrica's conjecture is true:
$$\frac{1}{n}\sum_{i=1}^{n}\left(\sqrt{p_{i+1}}-\sqrt{p_{i}}\right)=\frac{1}{n}\left(\sqrt{p_{n+1}}-\sqrt{p_{1}}\right)<\frac{p_{n+1}}{n\ln{n}}\cdot \frac{\ln{n}}{\sqrt{p_{n+1}}}\rightarrow 0, n \rightarrow \infty$$
this follows from Rosser's theorem.
From Vallée-Poussin
$$\pi(x)>\frac{x}{\ln{x}}>\sqrt{x}$$
from some $x$. But
$$\lim_{x\rightarrow \infty} \frac{\sqrt{x}}{\ln{x}}=\infty \Rightarrow \pi(x)>\frac{x}{\ln{x}}>4\sqrt{x} \tag{1}$$
from some $x$. The number of perfect squares in $\{1,2,..,n\}$ is $\approx \sqrt{n}$, the number of primes in that interval is $\pi(n)$, the number of primes containing a perfect square in between is $\approx 2\sqrt{n}$ (this may contain duplicates, but we approximate) and approximately (from $(1)$)
$$\pi(n)-2\sqrt{n}>2\sqrt{n}$$
from some $n$. This means that, within $\{1,2,..,n\}$, the number of primes without a perfect square in between is larger than those with a perfect square in between.
A very complicated problem remains, to prove the result for the pairs of primes having a perfect square in between, which is (sarcastically) a "smaller" subset ...
Answer: We have
$$pq \le \left(\frac{p+q}{2}\right)^2$$
if and only if
$$4pq \le p^2+2pq+q^2$$
if and only if
$$0\le (p-q)^2$$
so $pq$ does not exceed $n^2$ (This property is even true for all pairs of real numbers)
We have
$$\left(\frac{p+q}{2}\right)^2\le p(q+2)$$
if and only if
$$p^2+2pq+q^2\le 4pq+8p$$
if and only if
$$(p-q)^2\le 8p$$
So, if the prime gap does not exceed $\sqrt{8p}$ , your claim is true. This is the case for the primes $3\le p\le 10^8$ , so your claim is likely to be true for all primes $p$.
If we could show $q-p\le \sqrt{8p}$ for every odd prime , where $q$ is the prime following after $p$, then we would be done. If the Legendre-conjecture is true (between $n$ and $(n+1)^2$ is always a prime) , then what we need is likely to be true as well.
Comment: You are very close Peter,. A proof of this statement implies that there is a prime between $n$ and $n+\sqrt{2}\sqrt{n-1}$.
Comment: Yes Peter I know that the statement is true. My problem is to prove it for all primes.
Comment: This would probably require to prove Legendres conjecture, so there is not much hope.

some properties of consecutive primes


cannot chose any application in "Open With" for Windows 10

Question: I usually use NotePad++ as my default text editor. I am using Windows 10, and for example I like to set .config files to open using NotePad++.  Usually, in other version of windows you would click on Open with... and choose.  While I do have the Open with... option, it only allows me to select a few applications, or an option to Choose from store, which doesn't allow me to select Notepad++.  Is there any way to get the usual selection for any application back?
Answer: Beneath Choose from store you should have More apps and then Look for another app on this PC
Just try to scroll down.
Answer: Control Panel\All Control Panel Items\Default Programs\Associate a file type or protocol with a program .cfg
Look for another app on this PC
navigate to notepad++ location


My Minecraft optifine cape wont appear

Question: I don't know if this is the right place to ask but just about an hour and a half ago I donated to optifine to get a Minecraft cape and when I join Minecraft both single player and multiplayer the cape simply will not appear on my back. I even restarted the game and asked people on the hypixel server if they could see my cape and they all said no. I've been searching all over the internet for help and the things I found didn't work, like toggling capes on in the video settings. one website said I should change my optifine cape and it might work but when I DO try to change my cape on the optifine website it says that the password is invalid even though I know with 100% certainty that the password is correct, I even went to my email and found the email receipt I got for the payment going through and I checked my bank account and saw that the money had come out so I definitely paid for it. the optifine website doesn't specify whether it needs my Minecraft password or my email password either btw and I tried both passwords and it was STILL invalid.
Comment: DO NOT ENTER YOUR MINECRAFT PASSWORD OR YOUR MAIL ACCOUNT PASSWORD ON ANY OTHER WEBSITE THAN MINECRAFT.NET, MOJANG.COM, THE LAUNCHER OR YOUR MAIL WEBSITE/PROGRAM! Now you've sent them your password, so they can access your accounts! You should immediately change your Minecraft password and your mail password!
Answer: Optifine capes can only be seen with the Optifine version of Minecraft (or the Forge version with Optifine loaded), because it's not an official cape by Mojang. It's not saved on your account, but instead the Optifine version of Minecraft checks on Optifine's servers for a cape.
So of course other players can't see your cape and you can't either, unless they or you play with Optifine.
Also maybe it takes a little while for them to process your donation. Try again in the next few days (maybe it requires manual action and the people don't work on the weekend) and if it's still not there then, contact them and ask if it's finished processing.
Comment: I checked the website in the FAQ section and it said the cape should appear straight away
Comment: and yes I've already launched the game with optifine I'm not playing vanilla.
Answer: You need to have paid a certain amount of money to get the cape. Maybe you bought it from a fake site. If not, you probably didn't say that you wanted a cape. Always make sure it the real site you're on or you might end up wasting money.
Comment: It was definitely the official site, I never buy something from a website unless I know that its the official site for sure. it was 5 days ago I donated and I know I donated enough because I went on the cape section of the website and it said to type my username to change my cape and also said if you don't yet have a cape than use the link to donate and I did and it even got me to choose a cape (I used a custom cape). The money came out of my account and I got an email saying that it went through.
Answer: Just people have OptiFine cape can see OptiFine's cape of others people.
Cape can just be obtain by going to MineCon. OptiFine can't change your personnals skins details, just Mojang can be that.
I hope that my answer helped you !   :-)
Comment: That's incorrect, I could see other peoples capes even when I hadn't even donated, I could see my friends cape when playing on my realm. also, MineCon is no longer an actual convention, it is a livestream as of 2017 so the "go to MineCon to get a proper cape" isn't a thing anymore because they don't do MineCon capes anymore sadly.
Answer: After waiting about a week I finally have my optifine activated after I got a new email saying the cape could be activated now. thanks for the help.
Comment: This question is still marked as unanswered. Can you accept this answer by clicking the check mark to the left just to set it to "answered" and make it easier for people who are having the same problem to find your solution (even if you only had to wait for a delayed email)?

My Minecraft optifine cape wont appear


Why do Walter and Jesse no longer come in cars to the laundry

Question: At some point Walter and Jesse have to come in laundry trucks leaving their cars away. I understand Hank may watch Walter, but why Jesse?
Answer: It's not a case of Hank possibly watching Walt, it's more that the launderette was on his radar and known to him as a potential target.  If he'd been watching it over any space of time, he'd start to notice who goes there regularly.
If that person was someone he knew to have links to drugs, and also was a completely different race from the other employees there, then that's going to set further alarm bells of in Hank's head and confirm his suspicions that something illicit is going on (rightly or wrongly).
By having Walt and Jesse come in the back of a laundry truck, it looks like a regular drop off and doesn't raise any flags with anyone.
Answer: It is a plot hole.
If the lab is secret , then Walt could certainly drive to it as often as he liked provided that he had ensured he wasn't followed and he took different routes to and from it. The same would go for Jesse Pinkman, although he would had to been more circumspect as he al;ready had a police record and that could have been used to call attention to him as a suspect.
Taking them to and from the lab would have been a sensible plan from teh beginning. It would limited any visible connection between the two and the lab. And it would have made it easier to spot any potential tails as the pickup and dropoff sites could be placed under surveillance prior to their use. This very obvious piece of tradecraft seems to have escaped the writers.
In any case, Hank was originally suspicious of Jess Pinkman so if any one was going to be followed it would have Pinkman first and then Walter White , if or when any suspicion fell upon him as being involved in drug activity. It would have made sense to transport at least Jess from the very beginning and then later Walt as circumstances changed.


glBlendFunc and glClearColor alpha parameter

Question: In OpenGL for achieving a proper transparency effect I should use glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) but with that blending function an alpha parameter in glClearColor becomes meaningless. When I change an alpha parameter in glClearColor I still get the same effect. When can I use the alpha parameter in glClearColor? What kind of effects Can I achieve?
Comment: What effect are you trying to achieve?
Answer: glClearColor sets the color (and alpha value) a RGBA framebuffer will be cleared to with glClear(GL_COLOR_BUFFER_BIT). The framebuffer alpha value would be taken into account with GL_DST_ALPHA or GL_ONE_MINUS_DST_ALPHA blend functions.
However your regular on-screen window framebuffer usually doesn't carry an alpha value. Notable exceptions exist of course, for example transparent windows with the background shining through, but they're a bit tedious to set up, and will still receive all mouse events, even if over "transparent" areas.
Framebuffers with an alpha channel are mostly of interest als render to texture targets.
So in your case, the clear color is of no particular interest for you. You're much more likely interested in the 4th parameter of glColor4f or textures with an alpha channel.
Answer: Opacity is the Alpha, not transparency It means you can not see it at all when it's 0. When it is 1 you can fully see it. You can see it at half power, if it's 0.5f.
Comment: The question was about the alpha parameter in `glClearColor` and implicitly the meaning of a framebuffer's alpha channel I  general. Alpha is a user-defined property which can mean transparency, opacity or something completely different, depending on which blend equations are chosen.


tax income - working less than 12 months

Question: If I work less than a year (6 months) and I earn 26,000 per annum. However, I didn't work before, therefore in March the overall amount will be apox. 13,000. Am I entitled to the tax return as they deduct the tax off my salary monthly?
Comment: Please add a country tag, as how tax withholding is managed varies widely.
Comment: also please specify the start date so we can understand the significance of March.
Comment: The answer depends on how much is withheld - you may want to add that too (along with the country tag, of course).
Comment: Hi new user.  Yes, ***IF*** you paid more tax than you had to, yes you will get it back.  But be careful - the taxman always finds some reason you have to pay more. You know?  But yes in THEORY you would get back any excess.
Comment: _**If**_ you are in the UK (clues: use of "March": tax year runs 6th April to 5th April ~= "end of March"; plus use of "per annum") then yes you should either get (or be able to claim) the money back after the end of the tax year; or -- if you continue working -- they may reduce the next years tax deductions to compensate.
Answer: The amount of taxes withheld in a period will be based on your income for the period extrapolated out to an entire year, and taking into account the number of allowances you claimed.  So if you only work 6 months, and have no other income, then your total income for the year will be less than what your wihholdings were based on, and you probably will get a refund.
However, you won't know for sure until you actually file your tax return and calculate the amount due taking into account all deductions, exemptions, credits, and wihholdings. It's possible that you claimed too many exemptions on your W-4 and had less tax withheld than you should have, and would then owe tax when you file.


External Hard Drive To Android Tablet and Power Supply

Question: Is it possible via USB Y cable or any other means to connect a Samsung 10.1 30 pin to
an external hard drive and at the same time, an external power supply to the Hard Drive.
I have concluded getting an adapter for the tablet to go from 30 pin to USB.
Any other takes on this..
Thanks in advance.
Comment: possible duplicate of [Share external USB hard drive over USB between multiple computers](http://superuser.com/questions/227390/share-external-usb-hard-drive-over-usb-between-multiple-computers)
Comment: Judging by your attempt to comment on the answer below it appears you have lost control of your account.  You should consider [registering](http://superuser.com/help/why-register) your account as it will allow you to post comments to answers on your question.
Answer: It is very much possible, the hard drive can be powered seperately and connected to an android device by using a hub like the following : http://www.vantecusa.com/en/product/view_detail/586
You need an OTG cable for the device aswell, whivh you van get at any local store for a couple of dollars.
Comment: No go,I guess I should have been more specific.
The external hard drive is a portable USB powered.
The item mentioned for a fix is for SATA.


Server communication of RSA new pin mode using RADIUS

Question: I'm implementing RADIUS authentication procedure on a client in a java application.
The RADIUS Server uses RSA SecurID to authenticate the users. As known RSA SecurID uses a token. When a user forgets his pin for the token, the token can be set to a special new pin mode on the server which forces the user to set a new pin on the next login attempt.
As fas as I know the communication workflow with the server would look like the following:

Client: Send Access-Request Package to the Server with the usual attributes.
Server: Reply with a package indicating the special new pin mode
Client: Display an Interface to the user to enter a new pin. Send a package to the server containing the new pin.
Server: Reply with a Package saying that the pin has been successfully set.
Client: Display a confirmation message and ask the user for a new passcode which he created using the new pin on his token. I assume this is basically the same package as in step 1.
Server: Reply with an Access-Accept package if OK or and Access-Reject if Not-OK

For step 2, 3, 4 and 5 I do not know how the package structure looks like and therefore cannot implement any logic on the client. Has anyone knowledge about the Server communication with a token is in new pin mode?
Cheers
Simon
The tokens used look like this. To create a valid passcode you need to first type your PIN and hit the diamond key below the 7:

(source: comprosec.ch)
Comment: Are you talking about the RSA [SecurID](https://en.wikipedia.org/wiki/SecurID) token product?  The term "RSA" by itself usually refers to the [cipher algorithm](https://en.wikipedia.org/wiki/RSA_%28algorithm%29).
Comment: Yes, exactly. Just edited the question.
Answer: It turns out you need to look at the 'Reply-Message' (Type 18) attribute sent within the RADIUS packet from the server. It's very hacky, but it's the official solution since the RADIUS protocol doesn't support such states (see RFC 2865). Talk to your RSA contact, they can provide you with a test server and 2 test tokens to test your parsing code.
Here is what I have found out so far:

New-PIN-mode entry

Reply-Message contains "Enter a new PIN having from 4 to 6 digits:"

New-PIN-mode request confirmation PIN

Reply-Message contains "Please re-enter new PIN:"

New-PIN-mode success

Reply-Message contains "PIN Accepted"

Next-tokencode-mode start

Reply-Message contains "enter the new tokencode"


Interpreting the RGB or HEX value from a description of the color using NLP

Question: We do have models that predict the basic color from its description, by basic color I mean red, blue, black etc. But I would like to develop a model that can spit out the RGB or HEX colors by a description of it, an example being, "yellow that is glossy and sorta dark" should give the respective value for the same. Another example would be, "Clear green plastic". This is relative to 3d modelling where I input this text and change the material of the object on the screen.
Comment: Look at encoder-decoders more generally (not limited to NMT).
Comment: https://xkcd.com/1492/
Comment: @Loukik Encoders decoders are used in several applications, including (but not limited to) neural machine translation (NMT). For example, Seq2seq approaches are encoder-decoders applied to language (https://en.wikipedia.org/wiki/Seq2seq), autoencoders are applied to unsupervised learning of features (https://en.wikipedia.org/wiki/Autoencoder), etc. You might find things of interest in other approaches with the same enc-dec architecture principle.
Comment: @clef can you be a little specific?
Comment: @user3067860 whats that?
Comment: @Loukik https://www.explainxkcd.com/wiki/index.php/1492:_Dress_Color It's a cartoon based on an image of a dress that went viral because no one can agree on what color the dress is. In the cartoon, the two dresses are both the exact same color, just the background and the person change.
Answer: In fact, you want to translate "yellow that is glossy and sorta dark" by (170,173,11).
A good way to solve this, is by using a neural machine translation model.
Therefore, you can use a encoder/decoder system like many translation models, but with 3 digits as output. To achieve this, you will want to have training data with plenty of text to color translation, but they don't need to be too exhaustive if you cover enough scenarios. The output sequence could be 3 digits 170 173 11. The neural machine translation should adapt itself to the different results automatically, and make good predictions because we have a similar sequence structure as any language.
You have plenty of neural machine translation code examples, here is one among others: https://machinelearningmastery.com/develop-neural-machine-translation-system-keras/
Comment: Thanks for that, will use this idea
Comment: You're welcome. Be aware that the best output would be 3 integers digits, but it would require a specific decoder, i.e. some modifications of a language translation's decoder. It is due to the incremental nature of RGB digits: such a translation system should guess the increase or the decrease of R,G and B according to the color description (ex: "quite dark" means a decrease of each RGB values, or "very clear" means an important increase of each RGB values). This system would be better to translate shades than plain text as output.
Comment: yeah I was thinking about the same, I will have to try different ways and firstly gather the training data, do let me know if you have any links or references that might help, thanks once again.


force:recordData gives unsupported entity error for a newly created Business Platform Object BoatReview

Question: I want to use force:recordData component for BoatReview's addReview functionality. But I am getting this error "This entity is not currently supported by force:recordData." What else I need to do as per new entity setting to make it available for force component. I am new to this, went through existing questions but still issue is not resolved.
Answer: In my case BoatReview is not a custom object (Its a internal entity), so by default It was not enabled for LDS. To enable that I had to follow few steps and change core files. Those who are struggling with issue and are internal user, please follow my solution at internal thread on Slack. Just search this issue you will find the answer.


Is the marriage of disbelievers valid? Were the parents of Prophet (PBUH) married as per Islamic law?

Question: A Christian brought this argument. He stated that under Islam the polytheist marriage isn't exactly "valid". He stated the fact that the Prophet was born out of a disbeliever makes him a child of adultery (audhubillah). This really disturbed me and I wanted to make sure what the take is. I've already read ahadith where the Prophet stated that he wasn't allowed to supplicate for his mother indicating she died upon disbelief.
Comment: Please focus on one question per post.
Answer: The marriages of disbelievers among themselves are valid according to the predominant opinion (Hanafi, Shafi'i, Hanbali). This is evidenced by the following verses about the wives of Pharaoh and Abu Lahab:

وقالت امرأت فرعون
And the wife of Pharaoh said ...
— Quran 28:9

وامرأته حمالة الحطب
And his wife [as well] - the carrier of firewood.
— Quran 111:4

In these verses Allah has called called these women wives of their husbands, and He would not do that if they were not married in His judgement.
Further it is known that when a couple accepts Islam then their marriage is retained and they do not need to remarry. Also their children born before conversion are considered legitimate and inherit from their fathers. This would not be the case if their marriage was invalid.
The Prophet Muhammad ﷺ  is born through marriage and not zina.

خرجت من النكاح، ولم أخرج من سفاح، من لدن آدم إلى أن ولدني أبي وأمي
I was born from Nikah and not from fornication, from Adam till my father and mother.
— Sahih al-Jami'

Also on a side-note whether the parents of the Prophet ﷺ were disbelievers is a matter of dispute as some have argued for them being among the Ahl al-Fitrah and have offered alternate interpretations of the ahadith regarding his father and mother.
Comment: Jazakallah khairan for the references. If you happen to find a source for the first point about disbelievers nikah being valid, do send it. As for the parents of the Prophet, how do they then explain the hadith that says the Prophet PBUH wasn't allowed to pray for his mother?


How does an equity partnership relate to company's valuation?

Question: I was recently made a partner in the firm that I work in. I received 15K shares at a face value of $0. I was told that a vesting would occur after 5 years where the anticipated vesting price would be $17.50 i.e. I would receive $262K. Last Sep'23, I received a K1 stating i'm 0.2% partner in the company. The company is valued $2B. The math doesn't add up. What am I missing?
Comment: CPAs are usually local to where you are, but with a 0.2% stake in a $2B business I'd suggest not to be cheap on legal counsel.
Comment: Partnerships don't have shares. You should talk to a CPA to understand how this works
Comment: That's where i'm stuck. The CPA I was working with doesn't even know how to file a K1 properly so had to go with TurboTax due to shortage of time. Any knowledgeable CPA you can refer who is reliable and would not charge me a ton?
Answer: The first thing to do is either.

Contact HR or a senior partner you trust to discuss the numerous valid explanations for the inconsistency.

Then ask your CPA or lawyer to go through the agreement if necessary after doing #1

Vesting Schedule: You need to know the exact nature of the vesting schedule. Is it a lump sum?

Valuation Methodology: Crucial to understand. Who is valuating it and based on what method? Verbally say it's worth $2B and actually see the method could be 2 different things.

Share Class: Companies may have different classes of shares with varying rights and privileges. Confirm the class of shares you received. If I had to take a guess this would be the most probable reason.

Dilution: Has the capital of the company been diluted since your partnership?

Based on all this, your 0.2% could lead to a lot of different numbers.

Overall, you will need to seek outside professional advice on this if HR and partners cannot satisfy your query. It is probable that this could be easily answered internally.


Some basic probability dilemma

Question: So I started studying probability and while it seemed all ok I'm having trouble wrapping my head around this one. So the question is: We have 100 balls , 10 black and 90 white. In 50 tries what is the probability of getting 0 to 10 black balls? Now I need to get probability for excels BINOM.DIST function and am having dilemma. Do we need to calculate 1 black divided by total black (10) or getting 10 black out of 100 total? I get 0.1 for both cases and that makes this bit more confusing.
Comment: if this is HW please add the self-study tag
Comment: Your question is vaguely worded: could you please be more specific? After all, it's obvious that you *must* get somewhere between 0 and 10 black balls in 50 tries, making the probability 100%. That's so trivial, though, I would guess you really want to compute eleven separate probabilities: the chance of getting exactly zero black balls in 50 "tries," the chance of getting exactly one black ball in 50 "tries," *etc.* That brings up another ambiguity: what exactly is a "try"? It sounds like it would be observing the color of a single randomly drawn ball *and then replacing it.* Is this so?
Answer: Draws with replacement
Assuming you mean draws with replacement by tries:
To help you clarify the question: Is the probability in the binomial distribution the probability of a success or is the probability of drawing a particular ball given a success?
Draws without replacement
If you are looking for a distribution and draws without replacement. (ie what is the probability of drawing 0,1,2,3...?) then you should consider:
How many different states/draws there are where you take 50 from 100 balls? How many of the 10 black balls would you draw? How many of the white balls would you draw? How can you combine these into a probability?

Some basic probability dilemma


Mean centre on the roads network

Question: I am trying to evaluate the current police stations. so I want to find the mean point of crime points in the city and compare the OD cost matrixes of the results.
Is there any way to find the mean centre of points on a network?
Comment: So you want to find a location *on the network* that satisfies some "centring" criterion? Would the location that minimises the sum of squared distances along the network to the crime points work?
Comment: Well the arithmetic mean x and y coordinate (which is probably what arcgis gives) minimises the sum of squared distance in 2d space, so do you want the location that minimises the sum of squared travel times to the points?
Comment: Actually ArcGIS 10 has a function to find the mean center but it does not consider the network. I added the historic traffic to the network. so drive time is the variable to  centring.
Comment: I think so but not sure about the sum of squared travel times.
Answer: For 2D case there are many options possible. One of them is arithmetic mean as per @Spacedman comment. I prefer very elegant peel away techinque by @whuber

As one can see for the pattern of 'crimes' I've used the results are very close.
Note you cannot use weight (more than 1 crime in the same place) using peeling.
In case of network I don't see any other way but going through all network nodes and picking one that meets your criteria

In this case criteria is a minimum total distance of travel, perhaps total of squares is better. I guess it can be done using Network Analyst. I used networkx python package. Network shown has 2951 nodes and 3761 links (62 scenes). It took  45 mins on my rather solid machine. Time can be reduced using multi-processing

Mean centre on the roads network


Word 2010 caption has no number

Question: I am trying to place a Table caption above a table in Word 2010. It shows correctly in the insert caption box, but when it appears on the screen there is no number and no hyperlink colour. The word Table and the caption text appears, but no number? Why? How can I get my numbers to appear?
Answer: Try updating the labels by pressing CTRL+A and then F9. If that does not work, show field codes by pressing ALT+F9 and see if the field structure is there. It should look something like this: Table { SEQ Table \* ARABIC }
Comment: I Have the same problem as the above. Showing field code does not work as caption is not being inserted as a field that can be updated...
Answer: I had the same problem with Figures. To solve it, I inserted a second figure caption. When I did, Word assigned it the number 1. Then I used Alt+F9 to show field codes, copied and pasted the field code from the second caption to the first, and updated fields. I then had numbers (1 and 2) for both figures. You can delete the second one if you don't need it.
Answer: I tried Missy's solution but the second caption did not work.
However,it got me thinking, so I added a table, inserted a caption, and the "Table" label worked with a number field.  I then inserted a "Figure" label to the same table and it worked.
I copied the "figure" number field to the other figure captions that did not work before and they adjusted the numbering themselves.  Automatic numbering for the Figure labels worked automatically afterwards.

Word 2010 caption has no number


Make [install] a synonym of [installation]

Question: There are already two synonyms for installation: installing and setup. So install would fit, too.
Comment: Smells meta to me.  Burninate.
Comment: In Ask Ubuntu we removed this tag in favor of [software-installation]. In Unix and Linux we just banned it. StackOverflow is a programming oriented site, not a user oriented one, yet two user oriented sites removed a tag about a user/administrator task.
Answer: This is now done:
installation ← install
installation ← installer
installation ← installing
installation ← setup
And some more:
uninstallation ← uninstall
uninstallation ← uninstaller
Answer: Looking at the tag pages for install, installing and installation suggests they should be the same tag:
installation (synonym - installing):

The process of installation is the deployment of an application onto a device for future execution and use.

install:

Installation (or setup) of a program (including drivers, plugins, etc.) is the act of putting the program onto a computer system so that it can be executed.

It's high time this happened.


How can I create a clickable hyperlink in DocuSign after the document is complete

Question:
I have created a hyperlink in DocuSign like it is described here https://support.docusign.com/en/articles/How-to-create-a-hyperlink-in-DocuSign. Sent it to email and opened. All created hyperlinks were clickable. But after a document is complete hyperlinks can't be clicked. How can I create clickable hyperlinks? This is intended behavior or if something is missing in the API call?
Embedded doc hyperlinks are clickable after a document is complete but can't be clicked when signing.
Why it clickable only when signing?
Answer: Hyperlinks during the signing session are more of a DocuSign interface trick than anything else - they are not embedded into the PDF and thus become inactive.
In order to get a hyperlink that's clickable outside of DocuSign, you'll need to edit the underlying PDF to include it there. Since PDF links aren't clickable inside DocuSign, you can place a hyperlink tag in the same location (such as a text box with white-colored underscores) so that it's clickable either way.


Why won't my 3D model unwrap, even with all seams marked

Question: I made a basic character model, and I wanted to add textures, although I cannot unwrap it in the UV editor.
Comment: what do you mean when you say that you can not? You first need to select the faces you want to unwrap (select all if you want to unwrap all)
Answer: When you click "Unwrap", it will only unwrap whatever you have selected. In your screenshot, since you have nothing selected, when you hit Unwrap, nothing will happen.
In edit mode, select the parts you want to unwrap, then hit unwrap. If you want to unwrap the entire thing, you can select the whole model with "Select > All" in edit mode. Now that you have the entire model selected, hitting Unwrap should unwrap the full model


Is there an official blueprint of Hogwarts?

Question: I would love to make Hogwarts in Minecraft, but I have no idea what the whole castle looks like, or where specific rooms are inside. I have seen plenty of angles of it, but what I would like is some sort of official layout or blueprint of the whole shebang. Does such a resource exist?
Comment: The interior would be hard to do, because it can rearrange itself, and there are rooms which don't comply to the rules of Euclidian space.
Comment: I myself have built Hogwarts in Minecraft and you can check out my images if it will help you out! http://www.facebook.com/StaplersHogwarts
Comment: @vsz - Pistons and redstone can make rearranging rooms (though not often compactly), and Nether portals can defy Euclidian space.
Comment: If you do, please post a link here!
Answer: J.K. Rowling drew a basic layout of Hogwarts and its surrounding grounds:

I will see if I can find any other drawings having to do with Hogwarts specifically. I think the movies are really wonderful, and they have J.K. Rowling's input and approval, so using ideas from the movies should be within the spirit of canon, if not perfectly, technically canon. Sachin Shekhar has already mentioned the Order of the Phoenix video game; make sure you get another source or two verifying the game is based on official movie blueprints, as most movies have only partial sets and a lot of the Harry Potter movies are filmed in front of the green screen. Enjoy building Hogwarts!
Comment: Hmm. In *Quidditch Through the Ages*, it says that a regulation Quidditch pitch is 500 feet long and 180 feet wide at the center. That would make the scale somewhere roughly around 1":250'. So now you know. :D Connecting all the pieces of where rooms are located within the castle is the hard part, now. :P
Comment: @GabeWillard - You could take screenshots of the Marauder's Map to help place the different rooms. :)
Comment: +1 for the grounds map. Would you happen to know a rough scale of that map?
Comment: @GabeWillard -- I'm terrible at math so I wouldn't begin to muster a guess, and I don't know the scale from canon or J.K. Rowling. However -- and this would be time-consuming -- if you were to re-read the books, there are hints here and there as to the size of different aspects of Potterverse. I believe Hogwarts has 7 levels (as opposed to the, what, twenty-five we see in the movie when looking up at the changing staircases). The movie *OotP* shows the scale of Azkaban (it's *huge*). Thank you for the +1 :)
Comment: I found this quote and thought of this question. **Joshua from Navigation Primary School:** How were you involved in making the Harry Potter films and did Hogwarts look like you had imagined it? **JKR:** *Hogwarts looked just as I imagined it. It was the most bizarre experience when I walked onto the set of the Great Hall; it really was like walking into my own brain*. So I think you could use the movie sets in your quest to design Hogwarts.
Answer: Use official video game of Harry Potter & the Order of the Phoenix. It uses official movie blueprints, J.K. Rowling's drawings and books' descriptions to recreate known places of Hogwarts. Its not an action game. The main objective of game is to explore Hogwarts & follow story of movie/book. You can visit almost all parts of Hogwarts & stop to look around. You can use it to create Hogwarts in Minecraft.
Comment: Sounds like quite an undertaking!
Answer: You can actually buy a replica of the Marauder's Map.
This (in theory) provides a blueprint of Hogwarts. However according to the customer reviews, it does not provide a proper map, since major locations are missing.
Answer: Lego recently released a beautiful Hogwarts castle.
Buy it, read the instruction booklet, and follow the exact steps in Minecraft.
Comment: Lego is "licenced" rather than "official". It's rarely (if ever) to scale and large sections of the castle (as described in either the film or the books) will be missing.
Comment: @Valorum For Minecraft, it's the best you'll get.
Answer: There is an excellent map that can be found at http://www.oddment-tweak.com/, that is very helpful in getting an idea as to how Hogwarts is laid out.
Comment: @ Niall: In this case "including the essential part" should be copy here all maps from the remote site: I do not think this is acceptable. There is the Wayback Machine for old invalid liks. This answer is good as any other.
Comment: The Harper Robertson map isn't canon. It's fan-made; http://readingharry.com/news/harper-robertson-vision-of-hogwarts/


Ethereum adoption in Enterprise without tokens/Ethers

Question: from an enterprise perspective, we may not need to deal with tokens/ethers.
Can an enterprise use ethereum at the same time decide not to use tokens/ethers (for example not supplying gas for every transaction)?
such financial arrangements could be made outside of the transactions by participating organizations.
Answer: Consortium networks can use Ethereum technology. The network design constraints are different and that means consortiums can apply different approaches to specific concerns:
Since members of a consortium network are known and admitted into the system by a governance process, they don't generally need to address large numbers of anonymous bad actors. A return to accountability negates the need for some of the processes one finds on public networks.
The public system relies on economic incentives to financially punish mischief by unidentifiable assailants. This is the core purpose of the ETH token. If a unit of account wasn't required to incentivize good actors it wouldn't exist at all.
As it happens, the public network boasts rather impressive replication and strong assurances that contracts will always run as coded. Strong assurance of the integrity of the system and the fact that it's accessible to everyone are two key properties that make codified tokens possible. It does not imply that tokens are the only valid use of a public system that provides exceptionally high assurances. It does, however, imply that it is not possible to summon thousands of participating computers to assist with a transaction without attaching a small fee for transaction processing. On public network, "who pays?" is an ever-present concern at a granular level. There is no possible way to make a state change free.
A network of vetted participants that achieves convincing assurance that Byzantine nodes will be ejected and does so without a financial incentive has no need for an incentive-based solution. The "coin" concept is absent in the design of systems like Quorum (Enterprise Ethereum) and competitors such as the Hyperledger projects. There's just no need for it.
Having said that, software patterns around "tokenized" assets and documents are often very applicable even a context where there is no cost to execute a transaction and no expectation that the "database" is compatible with exchanges or convertible to other currencies.
Hope it helps.
Answer: If you are talking about a private Ethereum blockchain, then yes, you can forget about gas usage (set its price to 0) if you want to. Also, nothing forces you to use tokens within the network - tokens are just smart contracts and if nobody writes token contracts on the network there will be no tokens.


Lossless extraction of streams from WebM

Question: I would like to extract streams from WebM video files without converting them (re-compression), can somebody recommend any software that can allow this?
Answer: To extract audio from a WebM file, using the ffmpeg tool (https://www.ffmpeg.org/download.html) :
ffmpeg -i "input.webm" -vn -acodec copy "output.oga"
Explanation :
"-i input.webm" designates the input file
"-vn" removes the video stream from the output
"-acodec copy" tells ffmpeg to copy the audio stream as-is (no re-compression)
"output.oga" designates the output file.
NB : Use quotes "" around filenames that contain spaces.
The output file extension has to match with the format of the audio stream contained in the source webm file.
I use ".oga" as output file extension because most webm files I handle contain Vorbis audio.
".oga" is the prefered extension in this case, even if .ogg is still a frequently encountered extension for vorbis audio-only files.
This command line based on ffmpeg should give you the audio format from the source file :
ffmpeg -i "inputfile.ext"
Search for the line containing the text "Audio", usually near the end of the command output.
In my case, this is the output :
Stream #0:1: Audio: vorbis, 44100 Hz, stereo, fltp (default)
Reading this wikipedia page might give you some insight on which file extensions should be used with which audio formats : http://en.wikipedia.org/wiki/Audio_file_format
Comment: If the webm source has a [Opus](https://en.wikipedia.org/wiki/Opus_(audio_format)) stream, the`.opus` file extension is encouraged.
Comment: Thanks for a detailed answer! I actually needed to convert the audio to AAC (because XLD doesn't support OGG yet), so I had to just switch the audio codec flag to use AAC. https://trac.ffmpeg.org/wiki/Encode/AAC
Comment: [Media Info](https://mediaarea.net/de/MediaInfo) is a good tool to inspect the, well, media info of media files. Can inspect files and folders and can output to userdefined formats. Which one could then input to ffmpeg.
Answer: Since WebM is a Matroska subset, mkvtoolnix should let you demux the files. It's open source, cross platform, and the author provides binaries for Windows.
Comment: How do I use it on webm files?
Comment: I don't see any demultiplexing options in the latest version of MKVToolNix.
Answer: With MKVToolNix – Matroska tools for Linux/Unix and Windows:
mkvextract.exe "file.webm" tracks 0:"file_audio.ogg"
(assuming audio track ID is 0 - you can check with mkvinfo.exe or mkvtoolnix-gui.exe)
Answer: Video files have a container format and codec formats.
Its hard to 'extract' the video bits easily, but it is possible to change the container format to something you can consume whilst not altering the video bits:
ffmpeg using -vcodec copy (and typically -an to strip any audio)


Meaning and usage of the slang "gold"

Question: I often hear the word gold as a slang to describe something great such as "last night's party was gold" or "that movie was gold" etc. What exactly does gold mean and how do you use the slang?
Answer: It is commonly referred to as merit and stems from the rarity of gold and its use in medallions such as "Gold Medals." (Even this very Q&A board uses Gold / Silver / Bronze in its token system)
It is closest described as "priceless" when used in the context you described.
Comment: I don't know that "priceless" is necessarily the correct word.  Gold may be valuable, but certainly isn't priceless.
Comment: I think the meaning **in this context** is the same, ie "of the highest quality".

Meaning and usage of the slang "gold"


How many $2$'s are needed?

Question: There is a positive integer $N$. $N$ is made up of only two distinct digits- $2$ and $3$. $N+18$ is divisible by $37$. What is the minunum amount of times the number $2$ can appear in $N$? I'm pretty sure the answer is only one time. But how can I prove this?
Comment: are there any better tags I could use?
Comment: I'm afraid I don't share your optimism; the smallest count of twos I managed to come up was three.
Comment: @PeterKošinár but is it possible to prove that the smallest amount of two's is 3?
Comment: Note that $1000\equiv 1 \mod 37$ so you can reduce the problem to analysing the sum of digits (with some cases to check).
Comment: @MarkBennet Thanks. That should be an answer.
Answer: Let's start with a simple observation:
The number $37$ plays very nicely with powers of $10$... The value $10^m$ can only have three possible remainders modulo $37$: $1$, $10$ and $26$. If $N+18$ is divisible by $37$, $N$ must be congruent to $19$ modulo $37$. This observation will be quite useful in subsequent thoughts.
The number $N=2323323$ satisfies the given conditions and contains three twos. In order to show that we cannot satisfy the conditions given with fewer twos, we need to consider three cases:

Numbers consisting solely of digit $3$: An $m$-digit number of this form is equal to $$\frac{3}{9}(10^m-1)=\frac{1}{3}(10^m-1)$$
Using the observation mentioned above, we find that such numbers produce remainders $0$, $3$ and $33$ modulo $37$; none of which is equal to the desired $19$.
Numbers having exactly one occurrence of $2$: They can be obtained by the numbers in the preceding group by subtracting number of the form $10^k$ with $k\leq m$. The observation allows us to quickly conclude that the only remainders of such numbers modulo $37$ are $2$,
$7$, $11$, $14$, $23$, $27$, $30$, $32$ and $36$.
Numbers having exactly two occurrences of $2$ are just as easy to deal with; there are just more remainders to cover... but still no $19$ among them.
Comment: How did you come up with $N=2323323$ or any N with three digits 2 to begin with?
Comment: Being lazy, I just ran a simple computer search :-) It can be done by hand quite easily too, though: Make a table consisting of four rows and $37$ columns (each column corresponding to one remainder modulo $37$). Mark cells $0$, $3$ and $33$ in the first row (those can be produced with no twos). Connect each marked cell in the first row with three cells in the second row; those $1$, $10$ and $26$ positions to the left of it (wrapping around from left to right if necessary). Do the same for third and fourth row. The path from cell $19$ in the last row tells you how to build your number.
Answer: Just another observation since I'm late to the party.
We can also use an algorithm for divisibility, which is to group the digits by threes from the right, and add them, repeating the process until we have a three digit number.  If that's divisible by 37 then so is the original number.
If the number is of the form $33...333$, then the number $+18$ is $33...351$.  The grouping sums form a pattern:
$$351, 354, 384, 684, 687, 717, 18, 21, 51, 351, ...$$
As none of these are divisible by $37$, there must be at least one $2$.
From there, it would remain to show that introducing one $2$, and then two $2$s, wouldn't produce any numbers divisible by $37$ either, and then it becomes a matter of searching.
You might be able to see that each $2$ rolls back the digit in the same place it lies in the group of three.  Then, $687-21=666$, which is two $2$'s in the tens place, and one $2$ in the ones place.
Hence, not only does $3323322$ work, but also $2323323$ and $3322323$!
Answer: Let $k$ be the minimal possible number of $2$'s. Let $N$ be a minimal number of the given form with $k$ $2$'s.
Since $333\cdot 10^n \equiv 0\pmod{ 37}$, $N$ does not contain three consecutive $3$'s. Thus only finitely many candidates need to be checked with less than three $2$'s. In fact, if $N$ has only $3$'s, then  $N\equiv 0, 3,$ or $33\pmod{37}$. If there is one digit $2$ somewhere, then $1,10,$ or $26$ is subtracted depending on its position; and the same for a possible second $2$ occuring. We need to achieve $19\pmod{37}$. Obviously, zero $2$'s don't work.
If we add $1,10,26$ to $19$, we get
$$20,29,8 $$
which is a set  disjoint from $\{0,3,33\}$.
All sums of two nombers in $\{1,10,26\}$ plus $19$ are
$$21, 30, 9, 2,18, 34.$$
again no match with $0,3,33$.
We conclude $k>2$. From $3323322$ we learn that $k=3$.

How many $2$'s are needed?


Linux Interrupt Handling in User Space

Question: In Linux, what are the options for handling device interrupts in user space code rather than in kernel space?
Answer: Experience tells it is possible to write good and stable user-space drivers for almost any PCI adapter. It just requires some sophistication and a small proxying layer in the kernel. UIO is a step in that direction, but If you want to correctly handle interrupts in user-space then UIO might not be enough, for example if the device doesn't support the PCI-spec's interrupt disable bit which UIO relies on.
Notice that process wakeup latencies are a few microsecs so if your implementation requires very low latency then user-space might be a drag on it.
If I were to implement a user-space driver, I would reduce the kernel ISR to just a "disable & ack & wakeup-userpace" operation, handle the interrupt inside the waked-up process, and then re-enable the interrupt (of course, by writing to mapped PCI memory from the userspace process).
Comment: When we do userspace driver, Does it make sense to clear interrupt in kernel or in userspace ? I think it should be clear when handling is done (so in userspace), Right ?
Answer: There is Userspace I/O system (UIO), but handling should still be done in kernelspace. OTOH, if you just need to notice the interrupt, you don't need the kernel part.
Answer: You may like to take a look at CHAPTER 10: Interrupt Handling from Linux Device Drivers, Third Edition book.
Answer: Have to trigger userland code indirectly.
Kernel ISR indicates interrupt by writing file / setting register / signalling. User space application polls this and goes on with the appropriate code.
Edge cases: more or less interrupts than expected (time out / too many interrupts per time interval)
Linux file abstraction is used to connect kernel and user space. This is performed by character devices and ioctl() calls. Some may prefer sysfs entries for this purpose.
This can look odd because event triggered device notifications (interrupts) are hooked with 'time triggered' polling, but it is actually asyncronous blocking (read/select). Anyway some questions are arising according to  performance.
So interrupts cannot be directly handled outside the kernel.
E.g. shared memory can be in user space and with some I/O permission settings addresses can be mapped, so U-I/O works, but not for direct interrupt handling.
I have found only one 'minority report' in topic vfio (http://lxr.free-electrons.com/source/Documentation/vfio.txt):
https://stackoverflow.com/a/21197797/5349798
Similar questions:
Running user thread in context of an interrupt in linux
Is it possible in linux to register a interrupt handler from any user-space program?
Linux Kernel: invoke call back function in user space from kernel space
Linux Interrupt vs. Polling
Linux user space PCI driver
How do I inform a user space application that the driver has received an interrupt in linux?

Linux Interrupt Handling in User Space


In RStudio, how to quickly hide/show a panel?

Question: Is there a keyboard shortcut to quickly hide the left/right panels in RStudio? I can drag the vertical bar to resize the panels but that's cumbersome.
Answer: I'm not sure that there's a hotkey for hiding the left / right / upper / lower panels, but you might find the shortcut keys for zooming to a given quadrant pane useful.
For example, in Linux (and I'm guessing Windows):
CTRL+SHIFT+1 = Zoom Source
CTRL+SHIFT+2 = Zoom Console
...
CTRL+SHIFT+0 = Show All Panes

The whole list of the pane zoom shortcut keys can be seen under the View > Panes menu. These hotkeys seem to be rather recent additions, as the earliest mention that I can see of them is for release v0.99.902.
Answer: To hide/show all the right panels you can use CTRl+Shift+1.
(this was tested in Rstudio 2023.06.2)


Two points are randomly selected on a line of length $1$

Question: Two points are randomly selected on a line of length $1$. What is the probability that one of the segments is greater than $\frac{1}{2}$? Points can be placed anywhere between [0, 1], for example. Thanks!
Comment: @TomUltramelonman  What if the first point is at $.1$ and the second at $.9$?  Then the segment between them has length $.8$.
Comment: @TomUltramelonman That's not correct. Two points divide a segment into three parts and *any* of them may be longer than $\frac 12$...
Comment: Notice that a line segment will only be greater than 1/2 if both chosen points are either both to the left or to the right of the middle point. So knowing this I guess you could work out the details
Comment: Oh damn, how could I overlook this ^^ Yea sorry
Answer: Probability is $3/4$ if points $x$ and $y$ are chosen with uniform probability. That corresponds to the area in color in the picture below.
Answer: With probability $\frac 12$ both points are on the same side of the midpoint, so we are guaranteed success.
If the points are on opposite sides of the midpoint(a probability $\frac 12$ event, with $P<\frac 12< Q$ say, then again with probability $\frac 12$ we have $Q$ is nearer $1$ than $P$ is near $\frac 12$,so the segment between them has length greater than $\frac 12$.
Thus the total probability Is $$\frac 12+\frac 12\times \frac 12=\frac 34$$
Note:  this is equivalent to asking how probable it is that the three segments formed by the two points can form a triangle (the above shows that the answer is $\frac 14$).  Many proofs for that can be found e.g. here
Answer: Ok suppose you take some point $x\in[0,1/2]$. Now taking a second point $y\in[0,1]$, there are two situations where you obtain a segment of length at least $1/2$. Firstly if $y\le 1/2$. Secondly if $y\ge x+1/2$. So for taking a first point $x$, the chance that you have a segment of desired length is $1/2+(1-1/2-x)=1 - x$. Now integrating this over $[0,1/2]$ you get $3/8$. Yu can do the same for $x\in[1/2,1]$. So this gives you a chance of $6/8$.
Comment: Thanks to lulu and CiaPan for the comments.
Comment: This is solid (+1).  My variant, below, does the same thing geometrically...without referring to an integral.  But the underlying principle is the same.


How long can a shutter be cocked before it is damaged?

Question: I have a Minolta SRT-101 for 35mm photography. I always cock the shutter right before taking a picture, however, if I decide not to take a picture what harm will it do if I have it cocked for longer periods of time? How long can I leave the shutter ready to fire before it starts to become inaccurate? Would I be able to leave it like this overnight or for a week?
Comment: Related: [Should film cameras be stored with a cocked shutter or not?](//photo.stackexchange.com/q/60492)
Answer: I have been doing this stuff since the 1950's, I have never actually seen damage to a camera due to the springs taking a set due to prolonged cocking. Not to say that can't happen as I was taught not to leave springs cocked for extended durations (storage). In my opinion, you can safely use photo equipment paying little attention to how you leave the springs. If you know you are going to shelf an item, try and remember to activate the shutter so the spring will not be tensioned for the duration of the storage. I think it is safe to say, if you forget, it's no big deal. I have retrieved cameras off the shelf that have been cocked ready for use, every one operated OK for me.
Answer: I would not lose sleep over it.
There are a number of film cameras - Rollei 35 in small and Bronica ETRSi in medium format come to my mind - that actually require you to cock the shutter after shooting. Rollei will not let you retract its little lens and Bronica will not let you swap lens without winding.
In both cases it is by design: you are meant to be ready to shoot the moment you pick up your camera (the Bronica also wants to ensure that both the lens and body are in the same state - wound / unwound). The springs of the shutter mechanism were designed to be kept in tension for extended time.
Answer: From a metalurgical standpoint, it isn't tension that causes a spring to lose strength, but repeated tension and relaxation. So leaving it either relaxed or under tension won't effect the strength of the spring that much over time. The parts that the tensioned spring is pressing against might fail if they are flawed or badly engineered. Like Jindra says, "I would not lose sleep over it."
Comment: As long as the spring is only cycled below its plastic deformation limit, then theoretically it should last forever and not lose any strength whatsoever. I imagine that the spring probably wasn't considered a failure part on the camera. As you note, the failure parts are probably the stops or retainers that the spring rests against, or the ratchet mechanism, or the ratchet bearings or bearing surfaces. Ditto: "I would not lose sleep over it". =)


How to attach soft tubing to glass

Question: I plan to do some amateur chemistry with some basic equipment. I've watched hours of youtube videos for how to bend and polish glass tubing and push it through rubber stoppers, and I've seen diagrams of such tubing attached to rubber or silicone tubing, but nothing showing how to do that. I've even searched through catalogs of equipment and seen lots of specialized gadgets with hose barbs and such, but nothing basic. I just want to do a simple thing: have a rubber stopper with a glass tube in it, and attach that directly to a flexible tube. Nothing fancy, just one tube connected to another. I see it in diagrams like http://www.mctcteach.org/chemistry/C2224/labman/vacfilt/filter7.htm , but it gives no explanation. What am I missing?
Comment: Why the downvote? Is this not a sincere question about lab procedure that's not answered by a Google search?
Answer: Heat up the soft tubing to make it easier to fit over the connection. Most labs have a heat gun that is used for this (amongst other uses). A hairdryer will serve, or put the end of the tubing in hot water. Many glass connection have what is called an olive which you have to push the tubing over while hot, when it cools it contracts giving a good seal (particularly important for the water lines of condensers which may be left overnight)
Comment: What "connection"? That's the whole of my question--plain glass tubing has no hose barb or anything like that. Am I supposed to just assume that the ID of the hose is a bit smaller than the OD of the glass? Do I attach a tube with an olive to the plain tube by melting them together?
Comment: For plain glass with no olive I would try to choose soft tubing with a smaller internal diameter and soften it so that in can be pushed over (carefully) the glass tube. This is not that satisfactory but should hold if there's not too much pressure in the system.
Comment: That should work. It just seems odd that there are hundreds of different fittings for special applications, but not a simple one just for this.
Answer: You do this with great care, putting rubber or plastic tubing onto glass tubing or taking it off is a major cause of injuries in a chemistry lab.
I always saw that the most dangerous object in my lab is a traditional liebig condensor with short bits of glass tube which you push the plastic water hoses onto.
The best way to do it with rubber hoses (such as semipressure / vacuum hose) is to dip the end into dichloromethane or chloroform to make the rubber more soft, then to push the hose gently onto the glass tubing. To remove it, it if often best to cut the tubing off rather than pull it off if the tube will not come off with ease.
For plastic hoses such as PVC it is best to heat the plastic tube up with a hot air gun to make it more soft before trying to put it onto the glass tubing.

How to attach soft tubing to glass


Convex quadrilateral and perimeter

Question: Convex quadrilateral $ABCD$ is inscribed in a circle with diameter $AC=729$. Sides $AB$ and $CD$ each have positive integer length. I have to find the perimeter if $BD=715$. By Ptolemy's theorem, there is $AB∙CD+BC∙DA=AC∙BD=521235$ and furthermore we have: $CD^2+DA^2=AB^2+BC^2=AC^2=3^{12}$. What can I do next?
Answer: Let $AB=n$ and $CD=m$. Then
$$mn+\sqrt{729^2-m^2}\sqrt{729^2-n^2}=729\cdot 715 $$
can be written as
$$(729^2-m^2)(729^2-n^2)=(729\cdot 715-mn)^2 $$
or as
$$ 729 m^2 - 1430 mn + 729 n^2 = 729\cdot20216 $$
which does not have many integer solutions. Except the obvious $(m,n)\in\{(715,729),(729,715)\}$ there are only $(m,n)\in\{(279,405),(405,279)\}$, leading to a perimeter equal to
$$ 279+405+180\sqrt{14}+162\sqrt{14}=\color{red}{342(2+\sqrt{14})}.$$

Convex quadrilateral and perimeter


How to track dates when new strikes are added to option chain for any underlying

Question: I believe exchanges try to maintain some range of ITM/ATM/OTM issues for a particular underlying/expiry pair. Eg minimum 5-1-5 to maximum 10-1-10, so there are atleast 5 OTM issues and maximum 10 OTM issues at any time for a given expiry/underlying.
How does one obtain this rule set or the dates when new strike options get issued to maintain this rule set.
Answer: This depends on the exchange. The exchanges I have access to release new instruments on schedule, prior to market open, and the strike range is relatively stable. It appears to be based on a formula.
Having rules in the database that alert on new instruments as well as on reference data changes can be useful in this regard. As an example, we have a bot that posts new instruments and changes to a dedicated private channel in Telegram, with a daily report as a backup.
Answer: The option exchanges have a set of general rules for the distance between strikes as well as a fixed schedule for when new expirations are added.
When an underlying first begins offering options, in-, at- and out-of-the-money strike prices are initially listed. New strike prices can be added as the underlying index level moves up or down.
Addition of new strike prices is a price driven not a liquidity driven event. IOW, they're not going to add further OTM strikes just because the Open Interest of current strikes is increasing with price relatively unchanged.
The liquidity of the options is a big determining factor.  For something like the SPY, there are can be 120+ different strike prices for a single expiration.
You can contact the CBOE and request that they add new strikes (see their web site). They will accommodate you if your request is reasonable such as adding a strike for a later weekly option that exists for earlier week(s).
Here's the general outline for CBOE equity options.
Answer: Strikes might be added by the exchange at the request of market participants, i.e. there is not always a set of rules that govern strike availability. I would suggest downloading the options chain each day and comparing to previous strikes, but this is by no means foolproof.


Can you make imines from Formaldehyde or Acetaldehyde?

Question: Title says it all. Wondering if imine formation would work with an aldehyde, even better would be formaldehyde.
Answer: Yes it does. They are reactive species, methylene imines particularly are easily hydrolysed back to amine + aldehyde.
They are the basis of reductive methylation/alkylation of primary amines where reaction with alkyl halides, especially reactive ones such as MeI risks dialkylation. More details here reductive alkylation
Comment: Thank you, I figured it would but couldn't wanted to make sure before I used it in a presentation. Also, I was wondering about alkylation of ammines for a while now!
Comment: @ronnie   Please accept the answer if you are happy with it


Risk of FX Targeted Accrual Redemption Note

Question: What is the risk of investing in FX Targeted Accrual Redemption Note (FX-TARN) ?
Comment: You will need to add more details about your product: can you explain how the payoff mechanism works?
Comment: The length of time before redemption is uncertain (unlike most fixed income securities, which have a predefined term). Generally you want it to be reedemed quickly, which happens if the referenced interest rate stays where it is or goes lower. But if the rate rises you will be "stuck" in the investment for a long time and your overall return will not be good. That is the risk: a rise in the referenced rate, which will lock up your money for longer than you expected, at a below average return.
Answer: An FX Tarn is a structured note whose coupons are calculated from a formula involving one or more fx rates, and whose maturity depends on the cumulative coupons received.  For example , the coupon could be $4pct*(1-FX_0/FX_1)$ where $FX_0$ is the Yen/Usd at issuance and $FX_1$ is the Yen/Usd on a coupon date.  The bond matures when the cumulative coupons received reaches 10%, say.  If this never happens the bond matures after 10 years.
Thus, the risk in this case is that the dollar weakens, causing the coupons to be reduced , and the maturity extends.  Thus, you own a low paying bond for 10years.