Was the word ἐπιούσιον used prior to the Lord's prayer? What does it mean?

Question: The word ἐπιούσιον has been translated in numerous ways, but the greatest modern consensus is to translate the word as 'daily.' Was the word ἐπιούσιον used prior to the Lord's prayer (Matthew 6:11; Luke 11:3)? What does it mean?
Comment: [The word used here in Peshitta is translated "needful, necessary"](http://www.dukhrana.com/peshitta/analyze_verse.php?verse=Matthew+6:11&font=Estrangelo+Edessa&size=150%).
This book contains an in depth look at the phrase from a Semitic perspective. [Tradition of the Text: Studies Offered to Dominique.  (Regarding the Lord's prayer, see pages 117-119).](http://books.google.com/books?id=iy0jfemCJzEC&pg=PA118&lpg=PA118&dq=mt%206:11%20peshitta&source=bl&ots=J50ECJdkQx&sig=LgsgjwVKV22graQOduI8ZTlZR5s&hl=en&sa=X&ei=_HgvUYa8Esby0wGB14HoBg&ved=0CE0Q6AEwBDgK)
Answer: Bruce M. Metzger writes in Bibliotheca Sacra 150 (July-September 1993) (pp 277–278):

The great majority of these hapax legomena occur also in other Greek sources, and so the meaning of most of them is not often in dispute. The meaning, however, of a word in the Lord's  Prayer as recorded in Matthew 6:11 and Luke 11:3 has often been debated. Does "Give us this day our ἐπιούσιον bread" mean "daily bread" or "bread for tomorrow"? Except in subsequent quotations of the prayer, no other piece of Greek literature is known to contain this word. The only time it seems to have turned up was in 1889 when A. H. Sayce edited a fragmentary Greek papyrus containing a householder's account-book listing the purchase of provisions. Here, according to Sayce, in one of the broken lines of the list was ἐπιούσι—, with the end of the word defaced. It is most unfortunate, however, that scholars who wish to double-check this information are unable to do so, for the papyrus fragment has disappeared and cannot be found. Furthermore its loss is particularly distressing because Sayce (whose shortcomings as a decipherer of Greek papyri were generally recognized) may have misread the householder's list. And in any case, even if Sayce did correctly read the word, lexicographers do not know much more about its meaning than was known before, namely, that the expression signifies either "daily bread" or "bread for tomorrow." In such cases when a word is susceptible of two equally legitimate renderings, translators have no choice except to place one in the text and the other in a footnote.—Bruce M. Metzger, "Persistent Problems Confronting Bible Translators"

Context might give us some clues.  It sounds a bit odd to ask for tomorrow's bread today (σήμερον).  Also, given Jesus' subsequent instructions to not be anxious about what we will eat, drink, and wear, the context lends itself to "daily" or regular bread. Especially striking is:

Therefore do not be anxious about tomorrow, for tomorrow will be anxious for itself. Sufficient for the day is its own trouble.—Matthew 6:34 (ESV)

So Jesus seems to teach that we ought to pray for our needs and then trust God to deliver.

Wikipedia cites A Greek-English Lexicon of the New Testament and Other Early Christian Literature for the primary definition of the word:

deriving from Epi and Ousia: necessary for existence, in agreement with Origen, Chrysostom, Jerome and others

It should be noted that Jerome only used supersubstantialem for Matthew's version of the prayer.
Chrysostom seems to take the word mean both daily and needful:

But mark, I pray thee, how even in things that are bodily, that which is spiritual abounds. For it is neither for riches, nor for delicate living, nor for costly raiment, nor for any other such thing, but for bread only, that He hath commanded us to make our prayer. And for "daily bread," so as not to "take thought for the morrow." Because of this He added, "daily bread," that is, bread for one day.
And not even with this expression is He satisfied, but adds another too afterwards, saying, "Give us this day;" so that we may not, beyond this, wear ourselves out with the care of the following day. For that day, the interval before which thou knowest not whether thou shalt see, wherefore dost thou submit to its cares?

Origen considers "needful" to be a better translation than "daily":

But it will be said that the word epiousion, needful, is formed from epienai, to go on, so that we are bidden to ask for the bread proper to the coming age, in order that God may take it in advance and bestow it on us now. Thus what was to be given as it were tomorrow would be given us today, today being taken to mean the present age, tomorrow the coming. Since, however, as far as I can judge, the preceding interpretation is better, let us go on to consider the added reference to today in Matthew or the expression daily written in Luke.

Conclusion
We can make an educated guess about what Matthew, Luke, or their common Greek source (Q) meant by ἐπιούσιον from context, etymology, and historical translations.  The various proposals ("needful", "daily", and "for tomorrow") cluster around the idea that we should ask for the required sustenance that ultimately only God can give.
Comment: Since Metzger wrote that, the original papyrus mentioned by Sayce was located in one of Yale's collections. Indeed it had been mistranscribed. See M. Nijman and K. A. Worp. "ΕΠΙΟΥΣΙΟΣ in a documentary papyrus?". Novum Testamentum XLI (1999) 3 (July), p. 231-234.
Answer: We have no records of the word being used prior to the Lord's prayer. The NET Bible translates:

6:11 Give us today our daily bread

They then note that other potentially valid translations would include "Give us bread today for the coming day," or "Give us today the bread we need for today."
Unfortunately, the Greek term appears only in early Christian literature such as Luke 11:3 and the Didache 8:2. Therefore, we have little to work with.
Working from the construction of the word and possible related words, we find επιουσιος might be related to επιουσα which means "tomorrow."
Comment: The main reference for the claim that the term only appears in the Lord's prayer seems to be B.M. Metzger, "How Many Times Does ΕΠΙΟΥΣΙΟΣ Occur outside The Lord's Prayer?" ExpTimes 69 (1957-58) 52-54.  It does not seem to be accessible online.
Answer: Take the word apart: έπι + ούσιον = on/upon/above essence/substance.  It most likely means "necessary for existence" or "more than necessary." Origen taught that the Evangelists invented the word. The earliest translations into Syriac interpreted the word as continual or for our need.  Supersubstantialis was the original translation into Latin by Jerome, but it was later changed to quotidianus, meaning "daily," in Velus Itala. English is based on the rendering from Latin. But the Orthodox Greeks, Slavs and Russians kept the original sense of the unique word when they recite the Lord's Prayer.
Origen, Chrysostom, and Jerome all understood it as "necessary for existence." This early Christian understanding (which is still retained by the Eastern Orthodox Church) has nothing to do with daily needs such as bread we eat for calories in our diet. Why would Jesus turn around and tell his disciples not to worry about food and drink right after telling them to ask God for it? The Latin best transliterates into English: this is "supersubstantial" bread that we pray for. It is a play on words also (deriving from ἐπιέναι/ἐπιόν): it is the bread of the age to come. Jesus himself is the bread of life; his bread is spiritual bread of eternal life. The Eastern Orthodox Church believes that it partakes of this bread in the Mystical Supper every Sunday.
Most evangelicals assert that it simply means "daily" and thus avoid the sacramental and eschatological language concerning the 'nature/essence' of the bread. Eastern Orthodox Christians believe that this rejection of the sacraments and this sort of language in scripture represents a quasi-Gnostic worldview. That is, the early Christians viewed the world only in terms of Uncreated (God) versus created (everything/one else). The Gnostics viewed the world as a dualism between physical matter and the spiritual realm, a worldview which early Christians rejected. Modern (post-Enlightenment) evangelicals often share this Gnostic dualistic worldview which rejects that physical and spiritual elements can both be holy and even mystically conjoined.
Lexicon Entry

ἐπιούσιος, ον according to Origen, De Orat. 27, 7, coined by the evangelists. Grave doubt is cast on the one possible occurrence of ἐ.
  which is independent of our lit. (Sb 5224, 20), by BMetzger, How Many
  Times Does ἐ. Occur Outside the Lord's Prayer?: ET 69, '57/58,
  52–54=Historical and Literary Studies, '68, 64–66; it seems likely
  that Origen was right after all. Found in our lit. only w. ἄρτος in
  the Lord's Prayer Mt 6:11; Lk 11:3; D 8:2. Variously interpreted: Sin.
  Syr. (on Lk) and Cur. Syr. אמינא continual (DHadidian, NTS 5, '58/59,
  75–81); Peshitta דסונקנן for our need; Itala 'panis quotidianus',
  'daily bread'; Jerome 'panis supersubstantialis' (on this JHennig, TS
  4, '43, 445–54); GHb 62, 42 מָחָר = Lat. 'crastinus' for tomorrow. Of
  modern interpretations the following are worth mentioning:

deriving it fr. ἐπὶ and οὐσία necessary for existence (in agreement w. Origen, Chrysostom, and Jerome are e.g. Beza, Tholuck,
  HEwald, Bleek, Weizsäcker, BWeiss, HCremer; Billerb. I 420; CRogge,
  PhilolWoch 47, 1927, 1129–35; FHauck, ZNW 33, '34, 199–202; RWright,
  CQR 157, '56, 340–45; HBourgoin, Biblica 60, '79, 91–96; Betz, SM p.
  398f, with provisional support).
a substantivizing of ἐπὶ τὴν οὖσαν sc. ἡμέραν for the current day, for today (cp. Thu. 1, 2, 2 τῆς καθ' ἡμέραν ἀναγκαίου τροφῆς;
  Vi. Aesopi W. 110 p. 102 P. τὸν καθημερινὸν ζήτει προσλαμβάνειν ἄρτον
  καὶ εἰς τὴν αὔριον ἀποθησαύριζε. Cp. Pind., O. 1,
  99.—Acc. to Artem. 1, 5 p. 12, 26–28 one loaf of bread is the requirement for one day. S. ἐφήμερος.)—ADebrunner, Glotta 4, 1912,
  249–53; 13, 1924, 167–71, SchTZ 31, 1914, 38–41, Kirchenfreund 59,
  1925, 446–8, ThBl 8, 1929, 212f, B-D-F §123, 1; 124, PhilolWoch 51,
  '31, 1277f (but s. CSheward, ET 52 '40/41, 119f).—AThumb, Griechische
  Grammatik 1913, 675; ESchwyzer II 473, 2.
for the following day fr. ἡ ἐπιοῦσα sc. ἡμέρα (cp. schol. Pind., N. 3, 38 νῦν μὲν ὡς ἥρωα, τῇ δὲ ἐπιούση ὡς θεόν=today viewed as
  a hero, on the morrow a god; s. ἔπειμι): Grotius, Wettstein; Lghtf.,
  On a Fresh Revision of the English NT3 1891, 217–60; Zahn, JWeiss;
  Harnack, SBBerlAk 1904, 208; EKlostermann; Mlt-H. p. 313f; PSchmiedel:
  W-S. §16, 3b note 23, SchTZ 30, 1913, 204–20; 31, 1914, 41–69; 32,
  1915, 80; 122–33, PM 1914, 358–64, PhilolWoch 48, 1928, 1530–36, ThBl
  8, 1929, 258f; ADeissmann, Heinrici Festschr. 1914, 115–19, RSeeberg
  Festschr. 1929, I 299–306, The NT in the Light of Modern Research,
  1929, 84–86; AFridrichsen, SymbOsl 2, 1924, 31–41 (GRudberg ibid. 42;
  3, 1925, 76); 9, 1930, 62–68; OHoltzmann; ASteinmann, D. Bergpredigt
  1926, 104f; FPölzl-TInnitzer, Mt4 '32, 129f; SKauchtschischwili,
  PhilolWoch 50, 1930, 1166–68.—FStiebitz, ibid. 47, 1927, 889–92, w.
  ref. to Lat. 'diaria'=the daily ration of food, given out for the next
  day; someth. like: give us today our daily portion—acc. to FDölger, Ac
  5, '36, 201–10, one loaf of bread (likew. WCrönert, Gnomon 4, 1928, 89
  n. 1). S. also s.v. σήμερον.
deriving it fr. ἐπιέναι 'be coming' ⓐ on the analogy of τὸ ἐπιόν='the future', bread for the future; so Cyrillus of Alex. and
  Peter of Laodicea; among the moderns, who attach var. mngs. to it,
  esp. ASeeberg, D. 4te Bitte des V.-U., Rektoratsrede Rostock 1914,
  Heinrici Festschr. 1914, 109; s. LBrun, Harnack-Ehrung 1921, 22f. ⓑ in
  the mng. 'come to': give us this day the bread that comes to it, i.e.
  belongs to it; so KHolzinger, PhilolWoch 51, '31, 825–30; 857–63; 52,
  '32, 383f. ⓒ equal to ἐπιών=next acc. to TShearman, JBL 53,'34,
  110–17. ⓓ the bread which comes upon (us) viz. from the Father, so
  AHultgren, ATR 72, '90, 41–54. ⓔ The petition is referred to the
  coming Kingdom and its feast by: REisler, ZNW 24, 1925, 190–92;
  JSchousboe, RHR 48, 1927, 233–37; ASchweitzer, D. Mystik des Ap. Pls
  1930, 233–35; JJeremias, Jesus als Weltvollender 1930, 52; ELittmann,
  ZNW 34, '35, 29; cp. EDelebecque, Études grecques sur l'évangile de
  Luc '76, 167–81.—S. also GLoeschcke, D. Vaterunser-Erklärung des
  Theophilus v. Antioch. 1908; GWalther, Untersuchungen z. Gesch. d.
  griech. Vaterunser-Exegese 1914; DVölter, PM 18, 1914, 274ff; 19,
  1915, 20ff, NThT 4, 1915, 123ff; ABolliger, SchTZ 30, 1913, 276–85;
  GKuhn, ibid. 31, 1914, 33ff; 36, 1919, 191ff; EvDobschütz, HTR 7,
  1914, 293–321; RWimmerer, Glotta 12, 1922, 68–82; EOwen, JTS 35, '34,
  376–80; JHensler, D. Vaterunser 1914; JSickenberger, Uns.
  ausreichendes Brot gib uns heute 1923; PFiebig, D. Vaterunser 1927,
  81–83; GDalman, Worte2 1930, 321–34; HHuber, D. Bergpredigt '32;
  GBonaccorsi, Primi saggi di filologia neotest. I '33, 61–63; 533–39;
  JHerrmann, D. atl. Urgrund des Vaterunsers: OProcksch Festchr. '34,
  71–98; MBlack, JTS 42, '41, 186–89, An Aramaic Approach3, '67, 203–7,
  299f, n. 3; SMowinckel, Artos epiousios: NorTT 40, '42, 247–55;
  ELohmeyer, D. Vaterunser erkl. '46.—Lit.: JCarmignac, Recherches sur
  le 'Notre Père', '69; CHemer, JSNT 22, '84, 81–94; Betz, SM
  396–400.—M-M. EDNT. TW. Spicq. Sv.

William Arndt, Frederick W. Danker and Walter Bauer, A Greek-English
  Lexicon of the New Testament and Other Early Christian Literature, 3rd
  ed. (Chicago: University of Chicago Press, 2000), 376-77.
Comment: Howdy, theosis!  I've hunted down an article that I think explains the Latin translation and why you might think it's wrong.  You would be much better served by summarizing that (or something like it) rather than simply asserting "Truth".  Our site prioritized the display of your exegetical process more than individual conclusions.  (As an Evangelical, I'd prefer if you engaged more with the text and less with Church history, but that's your call, really.)
Comment: @theosis I think you'd find that actual Evangelical scholars would not approve of such a dichotomy. I'd happily stand corrected if you could cite your sources and not your straw men. Please be more careful about not flippantly bandying about such  accusations.
Comment: I also noticed that @JonEricson left your last statement mostly intact, yet you removed it. I happen to agree with that last statement (although not the 'tone' in which it was delivered), so I'm also going to add it back in with a slight explanation so that it comes off less as an accusation and more as an explanation. PLEASE review it to ensure I have captured your original intent.
Comment: Yes this is what I meant, but why waste time explaining all that? Good for you. If they just read their own history they would know this. I have no interest in explaining things anyone can read book to learn. I want to talk about stuff no books written yet for.
Comment: Additionally, this is quite the *ad hominem* don't you think? "Most evangelicals assert that it simply means "daily" and thus avoid the sacramental and eschatological language concerning the 'nature/essence' of the bread ..." I'd ask you to do a better job explaining this please. Are you saying that the Orthodox perspective is that ever meal is sacrament, or are you saying that this prayer is only for Eucharist? Before you attack/accuse my questions, I'd like you to know that either is fine with me, I'm just asking the context from which you are asking these questions.
Comment: Everything is sacramental in Orthodox, not just water, wine and bread. Because we believe matter is sacred, we not pagan dualists like most evangelical.
Comment: But I not have time to explain. I did not even explain in my answer, it was edited with that. I agree mostly, but I think you are limiting sacrament to special things not everything. God is everywhere present and fillest all things.
Answer: What does this word mean and connotate?
When the Israelites were in the wilderness, the manna appeared as an act of God's command, and so they were not mediately dependent on the manna for survival as much as they were immediately dependent upon God's very commandment, which brought the manna into existence in the first place. (Jesus quoted this line of reasoning to the devil by citing Deut 8:3 in this exact context.) The subsistence of bread therefore has to do with our reliance or dependence on the words of God, which for the Israelites was a "daily" occurance in the wilderness.
Now if our "inheritance" in the New Testament is not the geographical area of Palestine, but the heavenly Jerusalem above (Gal 4:26 and Heb 12:22), then our sojourn on the earth is indeed a wilderness journey of trials and temptations. Until we "cross the Jordan," we are "daily" in need of the words of God. These words not only provide the grace to give us "daily" food as nourishment for our bodies (for which we are of course grateful), but are also the very words that bestow eternal life upon us.
It is interesting that Jesus described himself as the manna from heaven (John 6:51), and then Peter replied that it was that Jesus had the very words of eternal life (John 6:68). So the words, or commandments of God, are the very source of life. It is no surprise then that Jesus is also personified as the "Word of God" in the New Testament.
ADDENDUM
In Exodus 16:4, the narrative indicates that the Lord had served "le mot du jour" to the Israelites as their food.
Ex 16:4 (NASB)

Then the Lord said to Moses, "Behold, I will rain bread from heaven for you; and the people shall go out and gather a day's portion every day....

In Biblical Hebrew, there is a play on words here (which I have highlighted in bold above). That is, the phrase "דְּבַר־יֹום" is not an adverbial phrase of time (as can be found in the Hebrew text of Ex 5:13 or Ex 5:19, for example), but is an objective phrase in Hebrew. That is, this phrase is the object of the Hebrew verb לָקַט, to gather or pick up. (In Ex 5:13 or Ex 5:19, "mud bricks" function as the object of the transitive verb לָקַט, and in those verses דְּבַר־יֹום functions as an adverbial phrase of time.) But in Ex 16:4 we read that the Israelites gathered "le mot du jour" from heaven in order to eat it -- that is, they were eating the DAILY ALLOTMENT of the WORD (of God). We know that this juxtaposition of meaning is certain because Deut 8:3 says so.
So the manna from heaven was the Daily Word ("Mot du Jour") from heaven. God's word therefore was their DAILY food.
Comment: He didn't cite any authorities on its meaning, so are we to take his word? He simply assumed "daily" is the correct meaning and went from there. That's not how it works.
Comment: I like where you are going with this answer (so +1), but I think you need to make clear right from the start that you are assuming "daily bread" and not some other meaning is correct.  The point of this question is that the translation of this word is tricky because Matthew, Luke, or their common Greek source ([Q](http://hermeneutics.stackexchange.com/a/1452/68 "If it existed.")) invented it.  Nobody had thought to compile dictionaries, so we need to find how the word is used elsewhere to know what it means.  But it's unique to the Gospels!
Comment: I'm interested in how he came to that meaning. Please share the process of how these conclusions were made - particularly the meaning of the word itself. I'm not following the logic in this response....
Comment: Jon - the "דְּבַר־יֹום" in Exodus 16:4 literally means "daily word" but the context was manna. (It therefore cannot stem from a Greek source "Q".) This bread of the day is God's revelation from heaven, whether manna, God's word, or God's son. When Jesus replied to the devil with Scripture, he was not relying on "Q" but on the Torah, which Jesus said had correlated the "daily bread" with God's word. Also, thank you for the +1 - it was an encouragement to bring me back to zero and "break even".
Comment: Okay, team, please read my addendum above. I hope that the addendum clarifies. Very Respectfully, Joseph.


What is the iTunes Connect role I need to add a new app?

Question: I don't see explicitly said in https://help.apple.com/itunes-connect/developer/#/dev82a173c41 what is the role I need. I guess it is 'admin', given 'Access to all sections within iTunes Connect.', but maybe other role can do it.
Answer: The Role Permissions documentation includes a table My Apps: App Store that states Create apps and submit versions is available to:

Legal
Admin
App Mgr

iTunes Connect Developer Help
Role Permissions > My Apps: App Store
Comment: true, although every time I try to create a new App I'm redirected to the initial page of iTunes connect...
Comment: and suddenly it starts working... wow...


Maximum number of members per Google Group

Question: I have 600 members in our club.  Currently I have created 6 Google Groups and have to send out 6 GG emails at least twice a week and adding and updating is a pain.  Is there any way to have 600 people in one group for free or do I have to have the Business version?
Answer: I have a google group (not business) with about 2000 members. Why do you think you are limited to 100? You can direct add only 100 per day - but the next day you can add 100 more. Or you can invite all of them to join, if they know how.


Flash message in control panel

Question: In short, I've got an extra background process running that syncs content for a given section to an external application as well whenever an entry in that section is saved and a certain toggle is set on that entry.
The background process itself runs smoothly, no problems at all there.
However I get a lot of questions from the end users saying they'd like to see some visual clue (besides the added job in the background processes queue) at the bottom of the sidebar. So I thought I'd show them a notice like you see when you save an entry (small blue bar at the top of the screen) indication when the external sync is triggered.
However I can't seem to find out how I can trigger such a message.
So I've got an Event::On block that does all the needed checks and triggers the jobs, and I'd like to expand that so it also shows a message.
Answer: I think setNotice is what you're after;
Craft::$app->getSession()->setNotice('Your message');

Flash message in control panel


Matrix query fails when using multiple fields

Question: I am on Craft3.5 and trying to build a matrix block query where I would like to return results from two different matrix blocks.  The docs seem to suggest that this is possible.
This is the code I have currently (in my twig template)
    {% set headingsAndNavPages = craft.matrixBlocks()
        .field(['contentBuilder', 'pageNavLink'])
        .type(['mainHeading', 'navLinkSettings'])
    %}
    {%
        set navItems = headingsAndNavPages
        .orderBy('navLinkOrder')
        .all()
        |filter(block => block.isNavLink )
    %}

The first matrix block has the handle contentBuilder and contains a type with handle mainHeading
The second matrix block has the handle pageNavLink and contains a type with handle navLinkSettings
The mainHeading and pageNavLink of the two matrix blocks contain fields with identical handles - see screenshot below showing them side-by-side

With the query exactly as above, I get an 'Unknown Column' exception:
SQLSTATE[42S22]: Column not found: 1054 Unknown column 'navLinkOrder' in 'order clause'
The SQL being executed was: SELECT `elements`.`id`, `elements`.`fieldLayoutId`, `elements`.`uid`, `elements`.`enabled`, `elements`.`archived`, `elements`.`dateCreated`, `elements`.`dateUpdated`, `elements_sites`.`id` AS `siteSettingsId`, `elements_sites`.`slug`, `elements_sites`.`siteId`, `elements_sites`.`uri`, `elements_sites`.`enabled` AS `enabledForSite`, `matrixblocks`.`fieldId`, `matrixblocks`.`ownerId`, `matrixblocks`.`typeId`, `matrixblocks`.`sortOrder`
FROM (SELECT `elements`.`id` AS `elementsId`, `elements_sites`.`id` AS `elementsSitesId`
FROM `elements` `elements`
INNER JOIN `matrixblocks` `matrixblocks` ON `matrixblocks`.`id` = `elements`.`id`
INNER JOIN `elements` `owners` ON `owners`.`id` = `matrixblocks`.`ownerId`
INNER JOIN `elements_sites` `elements_sites` ON `elements_sites`.`elementId` = `elements`.`id`
WHERE (`matrixblocks`.`fieldId` IN ('1', '55')) AND (`matrixblocks`.`typeId` IN ('1', '13')) AND (`owners`.`draftId` IS NULL) AND (`owners`.`revisionId` IS NULL) AND (`elements`.`archived`=FALSE) AND ((`elements`.`enabled`=TRUE) AND (`elements_sites`.`enabled`=TRUE)) AND (`elements`.`dateDeleted` IS NULL) AND (`elements`.`draftId` IS NULL) AND (`elements`.`revisionId` IS NULL)
ORDER BY `navLinkOrder`) `subquery`
INNER JOIN `matrixblocks` `matrixblocks` ON `matrixblocks`.`id` = `subquery`.`elementsId`
INNER JOIN `elements` `elements` ON `elements`.`id` = `subquery`.`elementsId`
INNER JOIN `elements_sites` `elements_sites` ON `elements_sites`.`id` = `subquery`.`elementsSitesId`
ORDER BY `navLinkOrder`

However, where I'm stumped, is if I remove either field name, it works perfectly - no exceptions, and the expected content (from whichever matrix block remains) shows on the page - eg if I change the second line to either .field(['contentBuilder']) or .field(['pageNavLink'])
So I'm a bit puzzled as to how the field apparently exists on each one individually, but not when they are combined?
I've also tried removing the orderBy() part of the query so the second part is
    {%
        set navItems = headingsAndNavPages
        .all()
        |filter(block => block.isNavLink )
    %}

However, when I do this, none of the items are displayed on the page  - but I can see them if there is no OrderBy query, provided that I only use one of the two fields.
Something does appear to be returned, but it doesn't seem to be in the correct format, or the expected data is missing, or something - I'm rendering an
 for every navItem, and I've got an empty
 tag rendered, but the actual content is not displayed.
I also found something about needing to include the id field in the first part of the query, in order for content to be shown, and that the matrix block id can be found in the URL when editing the field.
This confused me a bit as I can see the content without adding the id (provided I only use one field at at time), but I tried it anyway - both adding a single id, and both ids, eg
.id(1)
.id([1, 55])
.id(55)

However, I get nothing back at all with any variant of this, not even the empty
 tag is rendered
As far as I can tell, the issue seems to be caused by including multiple matrix blocks in the field part of the query.  I'm guessing that the data returned in this instance is somehow formatted or nested differently, so the field used in the OrderBy can't be found, and the fields I'm trying to render in my html are also not as expected.
But I'm not really sure where to go next - I'm struggling even with how to debug this, as I'm not sure how to even print the results in a readable format - I know you can use {{dump(var)}}, but this seems to print a lot of irrelevant information so I'm struggling to get anything useful from this.
Apologies if I'm missing something obvious here - I've never really used craft before and I'm struggling to get to grips with it.  I'm more used to Laravel and creating queries / writing PHP in controllers, so everything feels a bit alien!
If anyone can point me in the right direction either to accomplish what I'm trying to do with the two matrix fields, or even some suggestions on how to debug this, that would be most appreciated!
Answer: For anyone who may come to this in future, I've found a workaround that achieves the same thing:

Retrieve data from each matrix block separately
do any filtering needed on each block separately
merge the two resulting arrays, and use the 'sort' filter https://twig.symfony.com/doc/3.x/filters/sort.html

Resulting code is as below:
    {# Get data from first matrix block #}
    {% set contentBuilderHeadings = craft.matrixBlocks()
        .field(['contentBuilder'])
        .type(['mainHeading'])
        .all()
    %}

    {# do some filtering on the first set of data  #}
    {%
        set navHeadings = contentBuilderHeadings
        |filter(block => block.isNavLink )
    %}

    {# get data from the second matrix block  #}
    {%
        set pageNavLinks = craft.matrixBlocks()
        .field('pageNavLink')
        .type('navLinkSettings')
        .all()
    %}

    {# Merge and sort the two sets of data  #}
    {%
        set navLinks = navHeadings
        |merge(pageNavLinks)
        |sort((a, b) => a.navLinkOrder <=> b.navLinkOrder)
    %}

This results in a single array which can be looped and outputted in html, which is sorted by the navLinkOrder field as specified in the sort filter
I'm still not clear on why selecting from the two matrix blocks in the same query had such unexpected results, so any explanations on that are still welcome!


Use a sink sprayer on Shabas?

Question: Many kitchen sinks have a sprayer next to the regular faucet. Someone has told me that she grew up with the knowledge that one may not use such a sprayer on Shabas. I have never otherwise heard of such a prohibition; nor can I think of any reason it should exist. Does anyone know of such a reason, or of an authority who has said not to use (or who has explicitly said one may use) such a sprayer?
Comment: Perhaps _Zoreh_ like spitting into the wind? http://hebrewbooks.org/pdfpager.aspx?req=14171&st=&pgnum=288
Comment: @DoubleAA See _BHL_ there s.v. "_M'fazer_" who I think would allow a sink sprayer (and which would make an okay answer to my request for "who has explicitly said one _may_ use"). But maybe other _achronim_ differ.
Answer: From Rabbi Dovid Ribiat's The 39 Melochos (p. 378):

a) Aerosol spray cans
...
The Igros Moshe permits the use of aerosol cans on Shabbos because the scattering is not caused directly by blowing or wind-force, but rather by the pressure of the liquid as it is forced through the microconduits in the nozzle head. Since the scattering is not directly caused by the wind, it is not similar to Zoreh and is permissible.23
...
a-1) Faucet sprayers
Based upon the reasoning permitting the use of aerosol cans, it follows that one may use the "spray" attachment of the kitchen sink for washing dishes on Shabbos. Here too, the spray is not created by wind-force, but rather by water pressure forcing water through the small holes in the faucet or head of the spray attachment. (However, it is of course forbidden to use the hot water on Shabbos; only cold water may be used - see Bishul, Chapter V;1).
23 [Translation by Fred:] In the sefer Hilchos Shabbos by Moreinu HaRav Shimon Eider shlit"a, it is written that he heard directly from R' Moshe Feinstein ztvk"l to permit since "the prohibition of Zoreh applies when the wind scatters it, but here, the air contained inside the vessel propels it outside, and the scattering primarily occurs since it exits through a small aperture." I have also seen brought from the responsa Minchas Yitzchak (VI, §26) that everyone agrees that there is not even a rabbinic prohibition of Zoreh here.

In the footnotes in the back, Rabbi Ribiat additionally notes the general leniency mentioned by Rabbi Akiva Eiger (I, §20, cited in the Bei'ur Halacha mentioned in the comments on this question) that scattering water in the wind is probably permissible even according to the stringency of the Rama (OC 319:17, based on the Y'rushalmi Shabbos 49a), who prohibits scattering spit into the wind due to the m'lacha of zoreh (winnowing).
Comment: +1; many thanks. See also the comments to http://judaism.stackexchange.com/a/742.
Comment: does this include spray bottles as well? If permissible, can one change the settings of spray bottle knobs during Shabbat as well to get different dispersions of liquid?
Comment: @code613 Are you talking about the kind where you squeeze the handle to force the liquid out? It looks to me like the same principle would apply to permit, but CYLOR. I also can't think of a reason why adjusting the knobs would be a problem. If you are using the sprayer outdoors on a windy day, the case is less clear-cut. Also, it would be problematic to spray a scent on a garment or something.

Use a sink sprayer on Shabas?


Antique Chinese painting

Question: Before I ask I'd like to say how much I admire Chinese culture and art. Hence I always dig in antique shops for something from China. A few years ago I bought these beautiful twin paintings (not prints) and they look at least 100 years old, signed by the same artist. Sadly I cannot connect these painting with an artist and I've done some research. My last bit of hope lies in you, would you be able to help me to translate signature and seal. I will be very very grateful.
Comment: both the seal and the signature wrote: 李徯. It is the author's name
Comment: Guys!!! Thank you so much, I love you even more :) so the name of the artist is: Li Xi according to google translation, now I am very confused because I can`t find anyone with that name and the painting is at least 150y old,
Comment: Maybe he was not a famous artist
Comment: You're not going to have much luck looking for "Li Xi", because there are some 50 Li and some 50 Xi in Chinese (though your Li is the commonest one for surnames). It will help you more if you look for "李徯". Another hint: "画家" means "painter", and "绘画", "painting". Maybe if you show us what the painting look like, it also could help.
Comment: Also, use @ before the username, so people will be notified of your message. Like that: @joanna.
Answer: well the signature is (read top to bottom):
李 (u+674e):http://humanum.arts.cuhk.edu.hk/Lexis/lexi-mf/search.php?word=李
徯 (u+5faf):http://humanum.arts.cuhk.edu.hk/Lexis/lexi-mf/search.php?word=徯
then, the seal is the same (read right to left)
if you goggle, there's a 日本篆刻家協会会報,
www.n-tenkoku.jp/download/vol9.pdf
in page 10, there's the same seal, with info:
李徯 河井荃廬
https://ja.wikipedia.org/wiki/河井せん廬
he's a japanese seal craving artist (篆刻家); so, i guess that this seal "李徯" was made by him. further, it's reasonable guess that the painting is "made-by-japanese".
if you need further info, i would suggest you post the pictures in japanese language stack exchange :)
https://japanese.stackexchange.com

Antique Chinese painting


Shor's algorithm: initialization of second register

Question: I am trying to understand Shor's algorithm. I am not quite sure why the initialization, indicated as $|1\rangle$ in the below image at the bottom left is chosen as it is? I understand the modular exponentiation method in principle, but I am not sure which initialization should be chosen.
Comment: I would highly suggest that you look at this tutorial. https://qiskit.org/textbook/ch-algorithms/shor.html
Answer: For preference, in a phase estimation algorithm, you would set the state of the second register equal to an eigenstate of the unitary operator $U$, the plan being to find its eigenvalue, which depends on the period $r$. In fact, any of the eigenvectors $|u_s\rangle$ would do for values $s=0,1,\ldots r-1$ as these have eigenvalues related to $s/r$.
However, the eigenstates themselves depend on $r$, so without knowing $r$, you cannot make the eigenstate, and so you cannot find $r$. That's a problem.
The way to circumvent the problem is that you can prepare the state $|1\rangle$, and it turns out that this state is an equal superposition of all the vectors $|u_s\rangle$. Using linearity, you now know the outcome - an equal superposition of the estimates of the different eigenvalues (entangled with the second register). Thus, in effect, what the phase estimation does is it measures one of the $s/r$ eigenvalues at random (with equal probability). (You then use the continued fractions algorithm to figure out which $s$ it was.)
Comment: I understand now in principle, but why is that in the second (lower) register, the lowermost qubit is denoted $|1\rangle$ and not the uppermost qubit in the lower register?
Comment: It is that the entire register, when converted from binary to decimal, represents the number 1. It's not the state of a single qubit.
Comment: Why do some sources like Wikipedia https://en.wikipedia.org/wiki/Shor's_algorithm, or more profoundly Lomonaco, S., https://arxiv.org/pdf/quant-ph/0010034.pdf, not mention this eigenvector preparation of the second register?
Comment: Typically, there are two approaches to demonstrating Shor's algorithm: (i) build up from phase estimation, using eigenvector inputs, then make the jump to an input that is a superposition of eigenvectors. I believe this method gives the most understanding , or (ii) just happen to pick some particular input state, work though the calculation by brute force, and see that it magically works. It's a valid pedagogical option that comes down to author's choice.
Comment: how can Shor's algorithm in the case of (ii) work if we do not start with |1> as an input to the second register?
Comment: In general, it probably doesn't.
Answer: The initial state of Shor's algorithm is $\frac{1}{\sqrt N}\displaystyle\sum_{a=0}^{N-1}|a\rangle$, and it is OK to move this state to $\frac{1}{\sqrt N}\displaystyle\sum_{a=0}^{N-1}|a,x\rangle$ as our initial state since the modular exponentiation takes $x$ as one of its input.
Here shows the model of a $\text{controlled}-U$ gate, and a circuit for factoring (figure comes from this paper).

So I think the $|x\rangle$ denoted here directs to $|x\rangle$, although I do not know why they are doing so.
Comment: How do you explain why the ancilla register was put into state $|1\rangle$?
Comment: Which part do you refer to as the ancilla? The $|1>$ state in the figure should be the second input quantum register and the ancilla is kept hidden.


Is it ever legal in the UK not to have two brakes on a bike?

Question: When using a bike on a road in the UK, is it ever legal not to have separate brakes on the front and back wheels?
Answer: Yes. A fixed wheel does not need two, it needs only one (on the non-fixed, presumably the front, wheel).
Two separate and independent bracking systems, one per wheel, are required, but as the CTC say

Apart from saying that a brake that
  acts directly on a pneumatic tyre
  shall not be deemed to be in efficient
  working order, these regulations do
  not define how the brakes are operated
  (by hands, feet or maybe even the
  teeth?) or how they work. A lot of
  words are nevertheless devoted to
  wheels that cannot rotate
  independently of the pedals (i.e. no
  freewheel), the effect of which is
  that a fixed wheel drive counts as a
  braking system – on that wheel or
  wheels.

Note also that, when sold, European regulations dictate that it should be left-hand rear, right-hand front.
Comment: So the answer is, in fact, no - given that the fixie is acting as a brake?
Comment: We're arguing semantics - but the problem I have is that the answer is misleading in that its only legal *because* the back wheel is (in effect) a brake. So the answer is still no. Doesn't really matter that its not a brake in the sense of something that has cables and levers and pads (a back pedal brake would also not be a "brake" if we take that definition). Yes, you explain why but I still disagree with the answer starting "Yes" when in fact the answer is No, but the definition of "brake" means that a fixie only needs one rim brake (or similar)
Comment: If you think that in normal terminology a wheel is a brake, then no. But while legally a fixed's mechanism is considered to be a braking system, to most users of the language it wouldn't generally fall under what a normal reading of the original question would mean as a brake, i.e. a system of levers, cables and pads.
Answer: Not too sure on the legal standing on actually using the bike on the road - I think it extends to retailers legally having to sell bikes with brakes, and a bell too I seem to remember.
Comment: and reflectors on pedals!


In Pilot wave theory how far does the wave stretch?

Question: The one thing I find difficult to understand is how far does the Pilot Wave extend. Does the Pilot Wave permeate through the entire universe?
Comment: If you consider a real and physical explanation for the pilot wave, like photons emitted from an accelerated electron then yes. Photons travel across the whole universe as far as we know.
Comment: Yes. See David Bohm's interview in Copenhagen, 1989 https://www.youtube.com/watch?v=ifjD5aqaH-U
Answer: The "pilot waves" are nothing more or less than the ordinary position-space wave functions from standard QM. Thus they "extend" in the exact same manner - which could be through a very large region, or confined only to a very small one.
For example, with a hydrogen atom relaxed to its ground state, the "pilot wave" for the electron is the wave described by the usual orbital
$$\psi(r, \theta, \phi) \propto e^{-a_0 r}$$
In this case the electron, perhaps counterintuitively, shows no motion, because this is a "stationary state" with $\nabla \psi = 0$. Instead it hangs at some, unknown before a measuring experiment, fixed position that is almost certainly near the nucleus.
But the situation is identical to standard QM other than that there is now an added element of a hidden well-defined particle position underneath: the wave is very localized near the atom, filling up approximately its observed volume. In exact mathematical terms it is infinite because the exponential does not actually reach zero, but it becomes completely insignificant more than a few Bohr radii $a_0$ from the nucleus.
Answer: It does, yes. There are two different views; either there is a single 3N-dimensional pilot wave, or there are N 3-dimensional pilot waves, where N is the number of beables in the Universe. In either case the pilot wave(s) permeate the entire Universe.


1700 rated games-On mistakes and how to correct them

Question: What are some typical mistakes in 1700 rated games on Lichess, and what ways are there to correct them? I usually play blitz and bullet games. Occasionally I play. OVB and longer formats.
Comment: Hi Algebrah, StackExchange sites don't usually field opinion-based questions very well. I'd suggest [edit]ing your post to remove that line.
Comment: Thank you for suggestion  , I have edited it immediately
Comment: were there 1700 games or were some games played by a rating of 1700 player.
Answer: Even at 1700, the vast majority of your mistakes are going to be tactical errors...especially at the faster controls. The only way around that is to start studying and practicing.
There may be some people, who can benefit from online tactics, but am of the belief that they lend themselves toward the trainee being shallow, and often the answers are the computer answer, not the human answer.
I am a firm believer in books, so get yourself some good tactic books that are well-categorized. It is better to study specific categories at one time, pins, skewers, etc. I still love the Fred Reinfeld 1001 books.
Try to do 50 per day, spending no more than two minutes per problem. Note in pencil on a scale from 1-5 how easy you found the problem because you will do them again in the future. The more time you spend on tactics, the less you will lose online.
One last thing, and that is I have found that even mid-level players think they are pretty good at tactics, but it is my experience that they are not. I am no longer above 2200 USCF, but even when I was, I always felt I could be stronger at that, and general calculating.
Comment: Endgame study is fantastic. The basics I learned at 1100 USCF, I still have today, 40 years later.
Comment: Thank you for your input :) so some good tactic book and perhaps some book about endgame. I feel that I usually lose endgames when I am facing stronger players (2000+)
Answer: I recommend Dan Heisman's "The World's Most Instructive Amateur Game Book" which has 30 amateur heavily annotated games grouped by useful sections like "Too Fast" and "Too Slow"  for time management.  If you are often mystified by GM commentary like "...and Black is clearly better." then this book may be for you.
Most of these are in the 1400 - 1800 range.
Some quotes from the introduction:

Many amateur tournament players are superior to the average chess book purchaser
Typical mid-level tournament players often play strategically interesting games
Comment: Thanks , I will check it out


Does Piraha syntax lack any recursion or just embedding?

Question: I think we're all familiar with the background. Piraha is said to contradict the principles of universal grammar because it lacks embedding, but embedding and recursion aren't the same thing. Other forms of recursion exist. Does Piraha appear to have any?
Comment: Can you explain the difference between embedding and recursion? Note that even if Piraha does not exhibit any syntactic recursion -within- single sentences, Everett gave examples where complex 'multiply embedded' concepts can be expressed with multiple sentences, ie, "The man has a dog that killed the cat that ate the rat..." -> "The man has a dog. The dog killed a cat. The cat ate the rat...."
Answer: I take the word "appear" literally, that is, it's a question about the evidence. Almost all of the publicly available evidence comes from Everett. You can consult the other works on listed Glottolog (please only consult those where it is probable that the author personally worked with speakers of the language); you can also consult Everett's thesis from 1983, which may reveal relevant data not generally discussed. Or you could start with Nevins, Pesetsky & Rodrigues (2009) 'Pirahã exceptionality: a reassessment' in Language 85, which will tell about the interepretation if not the data.


Recognizing intervals without interval songs?

Question: I would love to know all my intervals by ear but where ever I search for help it says to learn interval songs e.g. Jaws theme for minor 2nd. I find this to be pretty ineffective honestly. I don't hear those songs when I am transcribing or improvising. So I would love some advice on how you guys learned to recognize intervals. I have done the whole thing where I sit at the piano and sing the same interval descending and ascending for an hour but that hasn't helped much either. Thanks for any advice in advance.
Comment: How do you know that it hasn't helped? (As for advice, I would suggest an ear training app)
Comment: I always liked remembering songs to remember intervals.  This probably works by appealing to our emotions, the song has meaning to us.  You shouldn't being hearing Jaws when you're soloing, but the point is to get better at hearing intervals on their own.  Ear Master Pro is a good software for ear training.  Band in a Box has an ear training video game.
Comment: The problem with trying to use a familiar tune to identify an interval is that the tune uses the interval _between fixed scale degrees_, e.g. between 1 and 4. But if you're then trying to identify a perfect fourth that's actually between 2 and 5 it's harder. Best sing scales, but not just up-and-down, but crabwise and other permutations too.
Comment: @BrianTHOMAS - Honestly, I thought that some interval songs using the tonic first (e.g. "Twinkle Twinkle Little Star" for perfect 5th), some other interval songs using the tonic last (e.g. "O Christmas Tree" for perfect 4th), and some rarer interval songs not using the tonic at all (e.g. "It Came Upon A Midnight Clear" for major 6th) would wipe out any association of interval songs with fixed scale degrees.
Comment: OK, take the opening four note horn motif in John Williams "Jurassic Park". This has a rising perfect fourth to the tonic, followed by a descending major third. The context makes even these familiar intervals sound exotic. And trying to match those sounds against familiar tunes is really hard.
Answer: Recognizing intervals is purely a matter of memory recollection. Hence, the most important aspect of interval training is the amount of time you spend practicing, not the particular technique you use to practice.
Reference songs (like Jaws) are useful because they anchor the interval to an existing memory. It's like taking a shortcut--you don't have to form a new memory of every single interval and can instead rely on existing memories that are already strong. However, it's okay to eschew this approach, because memories are pretty easy to form. Learning intervals without a reference song can work perfectly fine.
Regardless of where the memory comes from, your ability to recollect is strengthened with practice. Every time you retrieve the information from long-term memory (e.g., the information of what a minor second sounds like), you strengthen the memory and make its recollection quicker in the future.
Practicing intervals in the context of scales is very useful, as Heather S. describes. This is a particularly useful way to learn intervals when your goal is to transcribe, because it cultivates the ability to hear a pitch and immediately recognize its scale step. While extremely useful, it can be a crutch to only recognize intervals in the context of a given scale. Solos will often involve things like modulation, "playing outside" of the scale, non-diatonic chord progressions, etc. These are cases where it can be very helpful to simply recognize the interval.
So interval training is practiced most effectively when the student simply follows the usual best practices, like:

diversify your practice
spread out your practice
practice applying what you've learned

For the first item, you can practice both broken intervals (ascending and descending) and simultaneous intervals (chords). You can start the intervals on many different notes instead of always starting on the same note. Avoid playing every interval within just a single scale. You can play the intervals in different octaves and on different instruments. Instead of practicing just a major 3rd, you can also practice identifying a major 10th, a major 17th, etc. Randomize your practice so that the order the intervals appear in is always different. (An app or set of recordings with many different intervals could be useful.) For the second item, practice a little bit (e.g., 10 minutes) every single day for half a year, and by the end, you'll be an interval master. For the third item, transcribing is an excellent way to apply what you've learned. If you want to stretch yourself, find solos where the chord progression intentionally plays outside of the scale/chord progression.
Answer: Learning and singing major and minor scales and the relationships between the pitches of the scale is the best way to really learn intervals, in my opinion. Learn your solfege syllables. When sight-singing as Lawrence suggests, it is extremely helpful to know which role each note in the scale each note has.
Comment: Nice simple straightforward answer. It's important to know intervals from root note to whatever, but also intervals between notes to be sung/played. Tonic sol-fa works best with moveable do. I'm working with French musos at the moment, and their fixed do really messes me about - while they are excellent - in any key!
Comment: Thanks, @Tim. I do not really understand the usefulness of fixed do myself.
Comment: Yep.  Singing, even (or perhaps especially) for instrumentalists, is key to getting those intervals in the head.
Answer: My personal favorite exercise:

Get a standard deck of playing cards.
Rules
A. Red = Up
B. Black = Down
C. Number = # of semitones
Pick a starting pitch
Flip over a card and sing the corresponding interval up or down according to the color
Continue your way through the deck, checking periodically if you're on the correct pitch.

Suggestions

Start with just aces (half steps), then add twos (whole steps), then threes (minor thirds), etc.
As you introduce new intervals, you'll quickly get out of your singing range, so you'll also have to learn to make octave adjustments on the fly.
At the beginning, check every note, then every other note, then every third, or check every interval that tends to give you trouble.
When checking your pitch, it's helpful sometimes to check the exact pitch and other times to check relative to your starting pitch.
Try naming the notes either as an alternative or in addition to singing the pitches.
Instead of naming exact pitches, use solfege (do, re, mi, ...). Remember that your starting pitch need not be 'do', and choosing different starting syllables may help develop your contextual sense of pitch. This requires a chromatic solfege system.
Comment: Wow. I'm not always one for intervallic singing, but this is brilliant. And it's not an exercise limited to singing; it could be used to practice (non-sung) post-tonal interval distances, too.
Comment: @Richard In fact, Post-tonal singing is where I first learned it. But I use it routinely for ear-training in general. Glad you share my enthusiasm. It's good stuff.
Comment: This is brilliant. Is this your original idea? I've not come across this before.
Comment: @BrianTHOMAS I wish I could take credit, but no. It came from a choir director as training for singing post-tonal music.
Answer: Practice sight-singing from notation.  Real music, not just interval exercises.
Comment: Singing is key.
Answer: I think most of us have dabbled in the method of using songs to hear intervals.  My first intervals were STAR WARS for a fifth or, the starting note of BLUE MOON.
Frankly, I'm not a fan of gimmicks.  I suggest you go to your local church and steal a hymnbook (God will forgive you), okay, ask to borrow or have one, then AWAY FROM THE PIANO, take one or five hymns a day and sight sing the Soprano, then the Alto, Tenor and Bass lines.  It may be hard at first but it gets easier.
Then, AWAY FROM THE PIANO, sit down with staff paper and try to write out at least the melody. Hymns are great because they are easy, repetitious and short.
Knowing the numbers 1 through 8 in every key is mandatory. If you don't know, start off with all the hymns in the key of C, then F, then . . . Soon, you will hear music on TV or the radio and just know what the pitches are without thought. This is the secret to improvisation and "playing by ear." Far superior to the "hunt and peck method."
Without touching a piano, can you figure out these two ditties?  The starting pitch or key is irrelevant:
87654321 56 67 78
3212333 222 355 3212333322321
This, BTW, is the secret to sight transposing: Reading numbers instead of letters.  Letter readers are at a huge disadvantage because letters are absolute. Numbers unlock the universe of music.
Comment: Just using numbers is only half the job when sight-singing. I sometimes ask students to recognise well-known tunes, which I play with all the notes in the right order, but change the timing. Rarely get correct answers! Your first one's got me.  there's also the problem of notes with accidentals, as in non diatonics.
Comment: Do you have any specific hymn books to recommend ?
Comment: Any Protestant hymnbook should work.  Obviously songbooks won't serve your purpose.  You may also go to websites such as Hymnary and peruse thousands of hymns online:  https://hymnary.org/hymnal/CYBER


Is there re-syllabification in Chinese?

Question: I'm reading prosodic phonology, and wondering if there is any re-syllabification process happening in Mandarin Chinese?
Comment: The resyllabification here means the processes like French Liaison rules.
Comment: I do not know Mandarin at all. However, I believe I've heard of possible contractions formed from multi-syllable words that smush together different syllables. Would that sort of thing count?
Comment: By the way, what is the definition of "resyllabification"? I've been trying to find it.
Answer: Cholin 2010 ("Do syllables exist"), Chen, Chen & Dell (2002) ("Word-form encoding in Mandarin Chinese as assessed by the implicit priming task") claim there is not. Duanmu (1992: dissertation) claims that onsets are obligatory, so C#V resyllabification would not arise. However, he notes p. 18 that there are "weak interjection syllables" which allow C-V linking, viz. tian-a "Heavens!". This is consistent with the view that there is no resyllabification, as long as you don't initially syllabify this as .tian. + .a. which he accomplishes by claiming that the domain of syllabification is the word plus any weak suffix.
[EDIT]
This assumes what has become the standard theory of what resyllabification means: where a syllable is formed, then a morpheme is added or segments are deleted or inserted, and then syllable structure is re-assigned. Since there is no relevant epenthesis or deletion in Mandarin, only concatenation of words would count.
Comment: For syllables that seem to start with "a," is the obligatory onset considered to be a glottal stop?
Comment: Duanmu allows glottal stop plus γ (not a phoneme) and geminate [ŋ], so /mian ao/ "cotton coat" → *mian ʔao, mian γao, miaŋ γao* and *miaŋ ŋao* (and \**mianao*)).
Answer: (note: this answer is not complete, I am not a linguist and I have no personal knowledge of Chinese. I hope it is still of some use despite this.)
I have found several sources that say that resyllabification does not occur in Mandarin Chinese. However, it is possible that they are just making general statements, and not mentioning some rare examples.

syllables in Chinese are not re-syllabified in connected speech, for
  instance, 西安 (/xi1.an1/, capital of Shanxi Province in China) (a dot
  indicates a syllable boundary and the number indicates tone) cannot be
  falsely identified or pronounced as/xian1/(e.g., 鲜, fresh). In
  contrast, the syllable boundaries of a phonological word in Dutch or
  English differ from a lexical word's canonical syllabification. For
  instance, for the word "predict" (pre.dict), different contexts
  require a different re-syllabification, such as "predicted"
  (pre.dic.ted) when using the past tense and "predict it" (pre.dic.tit)
  when producing the cliticization.

(Masked Syllable Priming Effects in Word and Picture Naming in Chinese, by Wenping You, Qingfang Zhang, Rinus G. Verdonschot)

Mandarin has a limited inventory of syllables; syllables have a very
  simple structure and re-syllabification is absent.

(The Proximate Phonological Unit of Chinese-English Bilinguals: Proficiency Matters, by Rinus Gerardus Verdonschot, Mariko Nakayama, Qingfang Zhang, Katsuo Tamaoka, and Niels Olaf Schiller)
However, I also found this:

Yin (1986) proposes that the retroflexed rime in Beijing Mandarin is
  the result of re-syllabification of the stem and the retroflex suffix.

Mandarin Retroflex Suffixation: An OT Account, by Ma Qiuwu
The referenced paper is cited as follows:
Yin, Yun-Mei. 1986. An Autosegmental Approach to Retroflex Suffixation and Reduplication in Chinese. Taipei:
The Crane Publishing Co.
Unfortunately, I haven't been able to access this book yet, but I may be able to request it from my library. It seems in addition to the retroflex suffix, it also discusses reduplication.
Answer: Would you count erhua as a form of resyllabification? The er invades syllables like a facehugger to people.

哪儿 "where" (nǎ ér → nǎr /naɚ̯˨˩˦/)
一点儿 "a little" (yì diǎn ér → yì diǎnr /i˥˩.djaɚ̯˨˩˦/)
好玩儿 "fun" (hǎo wán ér → hǎo wánr /xau̯˨˩˦.waɚ̯˧˥/)
一瓶儿 "one bottle" (yì píng ér → yì píngr /i˥˩.pʰjɚ̃˧˥/)

In the last example, the ér literally replaces the nucleus of the prior syllable leaving only the initial and the medial intact.
Comment: I don't think this really counts, because -r and -ér aren't the same morpheme; the former is a suffix mainly with diminutive meaning, and the latter means 'son'/'child', and so there's no reason to think of -r and -ér as allomorphs synchronically.

Is there re-syllabification in Chinese?


Kinivo BTD-300 Bluetooth 3.0 dongle driver driver NOT on Kinivo site

Question: Relevant Specs:
OS: Win7 Home Premium
Machine: Acer Aspire 6676-7739g w/RAM upgraded to 8GB

Preamble:
I purchased a few months ago a Kinivo BTD-300 Bluetooth 3.0 USB dongle, and thus far have had very little issue with it. Today however, the thing didn't want to connect to my Bluetooth headset like it's been doing ever since I bought it, so I removed the headset from Bluetooth devices intending to re-pair it. However, the system wouldn't find the headset, despite being right next to each other and both devices being discoverable. In my very-ticked-off-from-something-else state, I've no idea why I thought uninstalling the dongle would be a good idea, but I did, and now when I try reinstalling, the system DOES NOT recognize the dongle, and the Kinivo support site DOES NOT offer the files in the mini-CD that comes with the device.
The "fun" part is that for reasons unrelated to this question, I no longer have the box/blister where the device came when I bought it, which had the disc with the drivers inside.

The Question:
Does anybody here happen to have the same BT dongle that can facilitate me a copy of the files in the included CD for this device via ISO or some other way? I realize this is partly my own fault for not backing up the drivers from the included disc, but considering that I had saved the box with all its contents, even the instruction manual until my work room got "cleaned up" by the maid, I did not even come close to suspecting I'd EVER lose that box. Now I'm stuck with a completely useless dongle that Win7 won't install, and despite my extensive Google-fu, these drivers apparently don't exist ANYWHERE on the internet.
Answer: I have the cd. Do you still need it?
Also, it looks like you can get the drivers online now:
https://support.kinivo.com/customer/portal/articles/664950-downloads#computer


What is the significance of the title "Agora"?

Question: One thing that's haunting me after watching the movie "Agora" is the title, What was the significance of this title?
Comment: agora - phobia?
Comment: @Richard  : This title relevance with the movie
Comment: Greek word: αγορα, transscription: agora, translates as: market.
Answer: It's from the Greek word "Agora", the meaning of which was

"gathering place" or "assembly".

Many sources discuss and confirm this, but I like Roger Ebert's description the best:

[Hypatia's] father Theon (Michael Lonsdale) was the curator of the Library of
  Alexandria, which had as its mission "collecting all the world's
  knowledge." Scholars traveled there from across the ancient world,
  doing research and donating manuscripts. It was destroyed by
  Christians in 391 A.D., and "Agora" takes place in the years
  surrounding that incalculable loss.
The film's title refers to a name for the public assembly places in
  ancient Greek city-states. The library was such an agora, and we see
  Hypatia teaching a class of young men who listen to her with open
  admiration.
Answer: Per wikipedia

The title of the film takes its name from the agora, a gathering place
  in ancient Greece, similar to the Roman forum.

This was explicitly confirmed in a huffpo interview with the film's lead actress; Rachel Weisz

W&H: The film was huge in Spain. A blockbuster. Can you explain the word Agora?
RW: It's an ancient Greek word that means market place. It's a place where people met. And I guess the premise of the film, or the
  conceit of the title is, the earth is an Agora. It's a meeting place
  for humans who don't get along.
Comment: As an aside, "agoraphobia" comes from "agora", and reveals it's true meaning as a "fear of crowds, or social situations", rather than a fear of being outdoors, which many people seem to think is the meaning.


User always tries to promote their product

Question: If you see all the post from this user Visual Micro. A great deal of his/her answers lead the user to a single product. Is this allowed by SE policy and should be flagged?
Comment: To be precise, 8 out of 25 posts refer to Visual Micro product, although, to be fair, at least [one](http://arduino.stackexchange.com/questions/12276/testing-arduino-with-visual-studio-community-2013-raise-lnk-error/13081#13081) of the answers was to a question about the product.
Answer: Users are allowed post good, relevant answers that talk about their own product or website as long as they disclose their affiliation with the product or website in the answer.
Overt self-promotion should be down-voted or flagged as spam.
The Help Center has a page that addresses this.

Post good, relevant answers, and if some (but not all) happen to be about your product or website, that's okay. However, you must disclose your affiliation in your answers.
Answer: S/he has made some posts which do not refer to Visual Micro. I'm a bit unsure about this one. If this Visual Micro product (which I don't personally use) is so great, why don't other people recommend it? That would be my first question.
I must admit some of my answers have links to my own web site, however I am not selling anything. Everything there is free for the taking, and the site does not have ads. Plus, I know StackExchange doesn't like "link only" answers, so I usually try to at least summarize the information I have on my site, so that the answer stands on its own. On the other hand, it seems silly to copy and paste huge swathes of text from one site to another (eg. how to make interrupts work) just to avoid posting links.
I might try asking this on Meta StackExchange, see if the issue is dealt with there.

In summary, I think answers along the lines of "My product XYZ from my website will solve that for you" are borderline advertisements. Especially if you have to pay for the product.
Without that disclosure, you may think that a trusted member of this site, not associated with the product, is recommending it.
Compare to some of my answers, like "I have code on my website that will solve that problem" (for free).

Related

Is sharing a recommendation for a paid product OK?

If you have used a particular product to solve a problem, it is ok to mention that in your answer, while also explaining how it is used to solve the problem.
It is not ok to link to a product or site in all your answers, or if the link is the whole answer. Especially not if it is your product or site.

How can I link to an external resource in a community-friendly way?

In my experience, posts with links are not downvoted if all these conditions are met:

you paraphrase the content of the linked item (possibly omitting details or examples)
you identify the author (yourself, MSDN, etc)
someone could benefit from the answer without reading the linked item at all
you include information to let the reader decide if clicking the link is worthwhile

Need explanation on the post removal

Linking to commercial products is a fine line to walk. If you are associated with the company that sells the product you link to, you need to disclose that ("our company makes a product called Frobnar, which you should look at").

Recommendations
Visual Micro (or any other similar user) be asked to do three things if s/he links to a related product page:

Disclose that s/he is (financially) associated with that site (it should be obvious from the user name, however some of those links do not mention the product by name until you have followed them).
Disclose that the recommended solution is a paid product
Provide enough information that you can tell, without following the link first, how the product would help, exactly.


What considerations are important when purchasing a new chain?

Question: Are there any special types out there or are they pretty much all the same?
Comment: What type of bike, gearing, etc... You can use tags to specify type of bike, and gearing.
Answer: The two most common sizes are 3/32" and 1/8"  Generally you would use 3/32" for bicycles which have dérailleur gears (road/mountain bikes).  As for length I believe they are all a stock length and you'll be very unlucky if you find it is too short.  You will need to specify how many speeds your freewheel or cassette is (6/7/8/9/10 speed).
You will obviously find lots of variety in quality/weight/material/price etc when you know which type of chain to look at.
Comment: Be aware that these aren't the only widths though. Before you buy anything check it is compatible with the manufacturer of your cassette (Shimano, Campagnolo, SRAM etc) and the number of cogs (5,6... 10,11 speed).
Answer: The last major change in chains happened around 1990, when Shimano changed to their HyperGlide technology. The goal of HyperGlide was to offer more sprockets but retain the same overall axle width for the rear wheel.
Since then, anything with 8 or more gears in the rear cluster has used the narrower chain.
There have been recent developments around asymmetric chains, where the plates on one side of the chain are different from the other side (which makes it possible to install a chain "backwards").
For most vanilla applications, there isn't a gigantic difference between the narrow Bell chain at WalMart and the SRAM chain at your LBS.


When did siddurim first start showing sheva na - nach differently?

Question: Some (most?) widely used siddurim today give the reader some pronunciation information that is not obvious in standard Hebrew lettering: when a sheva is pronounced (e.g., by making the sheva na bold, as in the Koren).  When did that information first appear in a siddur?
Comment: FWIW some Siddurim probably starting listing Shva-Na before they started including the line "HaYom Yom X..." which was only added after the Kitzur Shelah (~1700) and wasn't even that widespread at first.
Comment: My recollection - Siddur Shilo began emphasizing this. I have no proof that they were first. However, at least from what I recall from Nusach Ashkenaz & Nusach Sefard siddurim, I don't recall seeing this in Adler, Philips, Birnbaum (in 60's - maybe later editions began doing it?) or Tikun Meir.
Comment: @DanF later editions of Birnbaum do emphasise shva' na' and kamatz katon. I'm not a huge fan of them, but since I was gabbaing a minyan which uses Birnbaum machzorim over Rosh haShannah, I did notice that, as I did daven out of one (mostly). I believe that one of my grandfather's old siddurim, a Dutch impression from the 1830s (?) has a rafeh over shva' na' usage, although I'm not certain
Comment: @NoachMiFrankfurt I gather that Birnbaum was quite popular among the Yekke community. Would you have one dating from one of his very early editions? I'm curious if he began his siddurim this way.
Comment: @DanF, I don't know about it being popular amongst Jekkes (it's a fairly standard eastern variant of Nusach Ashkenaz) but I have a copy from one of the early editions. Currently, I'm away from my copy, so I couldn't check for features until I get back next week.
Answer: This siddur, printed in 1904, as well as this one, published in 1916, emphasize a sheva na by placing a line above the letter. For example:

בְֿ

However, not all Siddurim from this period emphasized them.
Comment: ArtScroll does this (I believe the line is called a rafe), and Kehot puts a star above each sheva na.


Will the armour piece where I put Protection affect its effects?

Question: If I put Protection on a Chestplate (for example) will it have a greater effect than on Boots?
Will Protection be more effective on some armour pieces than anothers?
Comment: Very nice question, I'm testing it now.
Answer: No.
While the mechanics of enchanted armor are different in 1.8 and 1.9, the protection enchantments reduce damage equally, no matter on which armor piece they are placed. There is a formula on the wiki to calculate the extra protection from enchantments (in 1.9):

The EPFs of all applicable enchantments are added together and capped at 20. The damage is reduced as damage = damage * ( 1 - cappedEPF / 25 ), giving a maximum reduction of 80% at EPF 20.

Only the total (capped) EPF (Enchantment Protection Factor) is used for the calculation, and EPF calculation is the same no matter what armor piece you are looking at. This is true for both 1.8 and 1.9.
I also ran some tests in the 1.9 pre-release right now. I created a 3x4x3 obsidian box with water at the bottom (to prevent burning), and a single block window at one side as well as the top open. The window was used to trigger a set of command blocks to teleport me into the center of the box and summon a Fireball with Explosion power 3 above myself, heading downwards:
/tp @a 59 57 1
/summon Fireball 59 70 1 {direction:[0.0,-1.0,0.0],ExplosionPower:3}

I put on a diamond helmet, boots, and chestplate, one of which was enchanted with Protection IV. The fireball consistently did 4 Hearts of damage, regardless of which armor item was enchanted. Without any enchantments, the damage was 5 Hearts.
Comment: Please note that damage mitigation formulas will change in couple of weeks with the release of Minecraft 1.9. Also, please indicate which version your answer is about.
Comment: @OrcJMR I ran the tests in the 1.9 prerelease, but the formula from the wiki might be outdated, which might explain why there was no randomness to the damage. I will look into it some more.
Comment: In 1.9 snapshots, full armour damage absorption was reduced from 80% to 66%.
Answer: I conducted an experiment to test your question(In 1.8.9) and the answer was NO.
First I tested each piece of leather armor without any effects:   Boots:
Chestplate:
Helmet:

Leggings:

Each test with normal leather armor ended with the same amount of damage taken. I had jumped from a height of 11 blocks and tested each armor piece one at a time with leather so the damage would be more significant and easier to read. You could probably draw the conclusion from this, but I decided to test just to make sure.  I gave myself Protection 2 leather armor and repeated the test.
I used a command like this:
/give @p leather_helmet 1 0 {display: {Name: "hat"},ench: [{id: 0,lvl: 2}]}

Although the damage was decreased by half a heart the damage taken with each one on stayed the same.  As a last and final test I gave myself Protection 4 armor and jumped from a height of 15 blocks to make sure that my data didn't change.
...As I had expected the data didn't change and the damage taken was equal even on different pieces of armor.  I received a damage of five hearts on each of the last jumps with the different individual armor pieces.
This test should prove that enchantments don't change the defense value depending on the armor piece within one set.
Comment: Wow, Pink Leather Armour.
Comment: What was your experiment? How much damage did you subject yourself to? Why did you test with leather armor, that reduces damage only slightly - are you sure you didn't overlook anything due to rounding?
Comment: Thanks for the questions, I edited my post to try and answer all those questions.
Comment: Unenchanted armour doesn't reduce fall damage, you know.


ECC error injection on Intel Xeon C5500 platform and issue with unlocking Integrated memory controller registers

Question: I am working on Error Detection module and was attempting to test using the error injection implementation mentioned in Intel® Xeon® Processor C5500/C3500 Series Datasheet, Volume 2  in section 4.12.40. It asks to program the MC_CHANNEL_X_ADDR_MATCH, MC_CHANNEL_X_ECC_ERROR_MASK and MC_CHANNEL_X_ECC_ERROR_MASK registers but attempting to write to this has no effect. Realized there is a lock for this space which is indicated by status in MEMLOCK_STATUS register (device 0: function 0: offset 88h), which in my case is reporting 0x40401 as the set value. This means MEM_CFG_LOCKED is set and I am not able to even unlock using the MC_CFG_CONTROL register (device 0:function 0: offset 90h). I am writing 0x2 to this register but that does not help to unlock the ECC injection registers for writing. How can I achieve this? I am running FreeBSD on the bare metal and not as a virtual machine.
Comment: `4.4.7 MEMLOCK_STATUS`, Bit 0 `MEM_CFG_LOCKED` has for the last sentence of its description the sentence _Can only be changed when in Authenticated Code Mode._ Are you?
Comment: Thanks for the reply. How does one enable Authenticated Code Mode?
Answer: To the best of my knowledge, the whole TXT thing that is necessary for this is not supported on FreeBSD.
But this a quite an arcane area. You might have more luck asking this on the freebsd-hackers mailing list.


Broken Shimano FD-R453

Question: I have a Shimano FD-R453 front derailleur that needs replacing. 50t and bottom pull with a 31.8 clamp.  There are three gears in the front and 9 gears in the back.  Could somebody help me with getting something similar as they don't make these anymore.
Comment: I did a quick search for Shimano 453 and 450 series. There was a 6 speed MTB group but no 9 speed. Can you check the group set series and provide us either the name? Was this road or MTB? Aprox how old is the bike?
Comment: Road Bike (Specialized).  The Bike is 7 years old, and bought it new.  Seems like they had a lot of trouble with the FD-R453.
Comment: Avid is the name on the hand controls on handlebars, does that help?
Answer: Looks like The FD-R453 is a non-series (i.e. it does not get the 'Tiagra', '105' etc label) component. I believe it's roughly equivalent to Tiagra in quality though.
Any Shimano 3x9 front derailleur is going to work, Tiagra 4500 series - which is not current but is probably available, Sora 3400 or 3500 series also. The Sora FD-3030-B looks right.
Comment: @jimmyg. Sora is Shimano's dedicated 9-speed groupset. For a triple front the latest selections are FD-3503, FD-3403, FD-3030.  The 3030 mech is designed for a 50t chainwheel.  Thought I'd offer that as you referenced "50t" in your question, which i assumed that to mean what you have now.

Broken Shimano FD-R453


When do I give notice to my employer if offered a job while on maternity leave?

Question: I wasn't actively looking for a job while on leave, but I was alerted to an opportunity at a company worth better benefits and they offered me the job. I'm on maternity leave and am due to return to work in about a week.
The new job knows of my situation and knows that if my current employer requires me to pay back the medical premiums, that I can't afford that and they are willing to wait until the waiting period for that is over. I need to find out if they would for sure require me to pay back the premiums, how much it would be if that's the case and what the date would be if I return for the time period required so as not to incur the cost (I simply can't afford to absorb it).
Do I go ahead and tell my boss now or wait until I return? Do I talk confidentially to my hr dept but not tell my boss until I have the info and can give appropriate notice?
Comment: "I need to find out if they would for sure require me to pay back the premiums". We can't help you answer this; you need to get this information from your company. Whoever you talk to there works for the company, HR included, and they won't necessarily keep confidential your intention to resign if you tell them. Congratulations on the new job.
Comment: HR is there to protect your company, not you--at least not except insofar as doing so protects your company, which doesn't appear to be the case here. In particular they will not collude with you to help you keep secrets from your boss on this sort of thing. Also if you're using your real name here, you might be exposing yourself to some risk by posting your situation on the web.
Comment: Can you ask if your new Job would take the medical premiums?
Comment: Asking the answers to these questions is going to require some incredibly delicate enquiries.  But surely all this information concerning your liabilities is spelled out in your contract.
Answer: I feel like you should look to either your employment contract, an attorney, or to your HR department to have your question answered.
If you don't have a piece of paper that you've signed / been given as a result of your employment explicitly outlining under what conditions you would have to pay this back for, I'm inclined to think that you won't be obligated.
Then again, it's not really my area.
If you don't have anything that specifies you must pay it back, ask the HR department for a list of employee policies. You may be able to find it along with other policies, and this allows you to keep your request vague.
If that doesn't work, you may have to explicitly ask whether employees are required to reimburse these payments under any scenario. Don't be specific about why you're asking.
Before doing so, it may benefit you to consult an attorney to see if there are any actual laws stating that you must pay this back or whether they can require you to pay it back or not.
Additionally: Change your display name on Stack Exchange. If you're worried about your company knowing that you intend to leave, you do not want your actual name associated with a question like this (Just to be safe).


Why is HCl the acid of choice for swimming pools?

Question: Why is muriatic acid the go to acid to put into pools? Does it work better than nitric acid, sulfuric acid, or another strong acid? I mean they all will add the same amount of H+ right? Note, we use some cyanuric acid as well, but mainly HCl for adjusting pH.
Comment: "muriatic acid" term is not used for many decades, some young chemists may not even know what it is. Hydrochloric acid is the term to use. I see this is not the first post combining the archaic term with pools and the author (you?) was already informed.
Comment: The HCl not only increases the acidity of the pool but also increases the concentration of "free chlorine", or as chemists like to call it, hypochlorous acid. This is why most pools smell strongly of bleach. Also, HCl is much cheaper and less dangerous than nitric and sulfuric acid.
Comment: @Poutnik well I took a few chemistry classes so I know it as HCL. But when marketed as pool supplies, they call it muriatic acid. Even says so on the box
Comment: Yes, I have already guessed it would be the case.
Answer: There are several reasons not to consider these acids to be interchangeable for use in swimming pools. A total answer covers aspects of chemistry, biology, safety, availability, and cost. As hydrochloric, nitric, and sulfuric acids are all strong acids and can provide the desired acidification, they are very different when you consider their respective counter ions. Do you want chloride, nitrate, or sulfate in your pool water?
Safety First:

Hydrochloric, nitric, and sulfuric acid are all strong acids that are capable of causing chemical burns and present inhalation hazard from their fumes.
Additional safety information can be obtained from PubChem.:
Hydrochloric acid
Sulfuric acid
Nitric acid

Chemistry:

Nitric and sulfuric acids are more corrosive to copper and stainless steel. Copper (I) chloride is significantly less soluble in water than copper salts of nitric and sulfuric acids. Swimming pool heaters are likely to contain copper pipe.
As an added benefit for salt pools, which use an electrochemical chlorine generator, the Cl- ions are converted to chlorine for disinfecting the pool water.

Biology:

As pointed out in another response, nitrates can promote algae growth.

Availability and Cost:

Hydrochloric acid is commonly available as muriatic acid (31.5% HCl, ~10 molar) from home centers, building and construction suppliers, and hardware stores, because it is used in many construction-related activities, with cost ranging from \$5 - 9 (USD) per US gallon. A gallon will contain approximately 37 mole equivalents of H+.
Sulfuric acid is available from auto parts retailers as battery acid (37% H2SO4) and costs approximately \$10 (USD) per US quart ($40 per gallon). A gallon of battery acid will contain approximately 36 mole equivalents of H+ (adjusting for normality). Sulfuric acid costs 4-8 times more than hydrochloric acid for equivalent pH reducing capacity.
Nitric acid is less readily available to the consumer market. One on-line supplier offered reagent grade (70%) for \$125 (USD) per liter.

Added Note:
Cyanuric acid is a weak acid and serves as a stabilizer. Quoting from PubChem:

Cyanuric acid is used in swimming pools to lower the rate of photochemical reduction of chlorine, hypochlorous acid and hypochlorite ion.
Comment: About the price of H2SO4 versus HCl, I have always thought the latter is generally more expensive with H2SO4 being the cheapest mineral acid. Is it possible that the "accumulator grade" H2SO4 is extra expensive, because like any product aimed to cars is often much more expensive than similar product not aimed on cars ? At least I have such experience.
Comment: @Poutnik Price and availability may depend upon country. I'm speaking for US markets and don't know what the situation is in Europe or other locations, which may be very different. For the US, sulfuric acid is also found in some drain cleaners, but those products contain additives, like gels and "metal inhibitors," that seem undesirable for a swimming pool. Muriatic acid remains the most cost effective. Acid concentration and additives are also treated as trade secrets for some products.
Comment: I had rather meant acid itself may be much cheaper than final products aimed to particular customers.
Comment: Comparing prices from Sigma-Aldrich (now Millipore), reagent grade H2SO4 (95-98%) costs \$85 (USD) for 2.5 L versus reagent grade HCl (37%) which costs \$108 (USD) for 2.5 L. Sulfuric acid is cheaper than hydrochloric acid, but readily available muriatic acid (31.5% HCl) is still less expensive for consumer markets.
Comment: Reagent grade is too good for pools, I guess.
Comment: I would agree with that.
Answer: The equivalent amounts of hydrochloric, sulphuric or nitric acid are interchangeable, acidity-wise. But there are other properties that may lead to prefer one over the others:
Nitric acid would provide nitrates as food to algae or other microflora.
Sulphuric acid is unpleasant for manipulation, as even tiny droplets  create during the time holes in clothes.
Additionally, but not sure if it happens, calcium rich water, when mixed with the acid, may locally and temporarily create a haze of calcium sulphate due its limited solubility, what could raise questions if anything is wrong.
Cyanuric acid is a weak acid ( weaker than acetic acid ), not well suitable for pH adjustment. It is rather used as the chlorine stabilizer.

Cyanuric acid is used as a chlorine stabilizer in swimming pools. It binds to free chlorine and releases it slowly, extending the time needed to deplete each dose of sanitizer.


Can I query a book in two countries simultaneously?

Question: Can I send a query to agents in non-English speaking country and translated version to agents in English country at the same time? I assume I have to inform them about this upfront. How it will affect my foreign rights in potential publishers' deals? Would it be better to focus on one country and then settle that with publisher?
Answer: Foreign distribution to a publisher means $$, so yes, you have to be honest when querying regarding your intent to market your work overseas. Understand, however, that such a move may be off-putting to many potential publishers.
Answer: Like Robjarvis said, it is about money...
When you meet with a publisher they will automatically try to take your foreign rights in the contract unless you demand them. They make money for an outright sale to companies all over the globe and the overseas companies own the intellectual property that should be yours.


How to convert an .xcf file/image to JPEG or PNG?

Question: I use the GIMP photo editor which automatically saves the converted files in .xcf format, but they cannot be reopened with any other app. How can I convert or save my images as JPEG or PNG?
Answer: You have to export the image, not save it.
To convert:

Open the XCF file using GIMP
Click on File
Click on Export
Enter a filename
It'll be saved as PNG by default. You can use any other format by simply adding the extension to your filename (like image.jpg, image.bmp) or selecting another file format in the bottom right of the export window.
Click on Export

The downside of exporting is that you'll only save what you see. So all your layers will be merged, and all editable components you may have added (like text) are not editable anymore.
So, if you would like to easily edit your images in the future, also save it as a XCF file as this will preserve all layers, components and other things as they are when you close GIMP.
Answer: .xcf is GIMP's native project file format similar to how .psd is Photoshop's native project file format. As Louis already explained saving in such formats has the benefit of being able to make modifications to editable components, which comes in handy when you work on big projects and have features like non-destructive editing and a history of modifications.
It makes sense to save into a project file format that is not intended to be viewed in a typical image viewer when you have users that use the program extensively for bigger projects and not just plain open, modify and save modifications workflows and you want to have a clear distinction between project files and image formats.
Earlier versions of GIMP allowed to save directly to standard image formats, this was remodeled into an export function with version 2.8. You can revert this through a plugin if you want:

GIMP 2.8 doesn't allow to save usual image file formats (jpg, png) via Save dialog
Answer: I have been using free XNView to quickly view (top layer) XCF for years. That will batch convert almost all image files too, original program worked perfectly in Windows, One of my favorite programs ever.
Downloaded the multiplatform deb to Linux Mint, works well so far, but can not vouch for stability or integrity. On Windows that new version had issues with a DLL to view SVG. (I didn't purchase that DLL.) No clue.
(It may have lagged the Nero copy working (extensively) from CD Rom drives, I am not using its file manager function now)
Comment: unfortunately, XnView MP Linux 1.0 (64-bit, April 29 2022) does not recognize current (v. 12) XCF files. It fails with a rather plaintive *not a picture* error


2002 Toyota Camry V6 Check Engine Light Code P1135

Question: I have a 2002 Camry V6 with 149,000 miles. My check engine light is on. The code is P1135 Bank1 Sensor1. I purchased an Upstream O2 sensor (Bosch) from AutoZone and changed the front one (right behind the fan) and reset the code. The check engine light went off for a brief moment. But, after a few second the light came back on. I went back to AutoZone, and the sales person told me that often both sensors go bad and suggested I change the rear Upstream O2 sensor as well, which cost another $130. I wanted to see if that's truly the problem and should I go ahead and change it. Please help. Thanks.
Comment: I had a broken flex pipe before the catalytic converter. Then I blew a rear spark plug. It is a 2002 camry xle v6. I replaced the exhaust system from the manifolds back and still had etc 1135, 420 + 430. First I replaced the O2 sensors and all codes cleared. The engine runs very smoothly and quietly. I have a new air fuel ratio sensor which I may not install if the CEL does not turn on again.
Answer: You may need to have your computer "un-learn" the old O2 sensor. Unplug the battery for about 30 minutes. This will reset your computer back to factory, where it will then have to relearn the new O2 sensor and might alleviate the situation. You will probably not know for several warm-up cycles if this actual solves the issue for you.
Also, did you double check to ensure you received the correct O2 sensor? Another thought is that the new O2 sensor might be bad. It would not be the first time this has happened. Here is what the code for P1135 is telling you (from Engine-Codes.com):

Possible causes
  - Faulty Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1
  - Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 harness is open or shorted
  - Air-Fuel Ratio (A/F) Sensor Bank 1 Sensor 1 circuit poor electrical connection
  - Faulty Engine Control Module (ECM)
  Help with Possible causes What does this mean?
  When is the code detected?
  The P1135 is set when the Engine Control Module (ECM) detects a heated oxygen sensor heater circuit malfunction
  Possible symptoms
  - Engine Light ON (or Service Engine Soon Warning Light)
  P1135 Toyota Description
Air-Fuel Ratio (A/F)sensor need to reach a minimum operating temperature of 1200 degrees F to produce an accurate voltage signal. The faster the air-fuel ratio sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM).
In order to achieve the require temperature, a heater element is included inside the air-fuel ratio sensor. The ECM controls the air-fuel ratio sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground.
The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.
Comment: I'd like to point out that you're not really unlearning a sensor it's resetting the stored fuel trims and other stored values.
Answer: The error code mentioned that heater part of the O2 sensor is bad. So it is easy to just check it with ohm meter before changing it. You should read below 20 Ohms on this element. Two of the wires are for element and another two for sensor. Do not connect Ohmmeter to the sensor because you may damage it depending to your Ohmeter.
Answer: bank one sensor one is the upstream sensor on the back side near the firewall not the front one near the fan. I also made this mistake. although if you had changed both you would have fixed the problem by coincident.
Answer: You changed the wrong one to begin with. Should have changed the one at firewall. That is bank1 sensor1. Bank2 sensor1 is by radiator.
Answer: If you did any work on the intake, double check the ground connection on the back. Loose nut can throw a p1135 AND 1150. Happened to me, but I unfortunately bought new sensors before checking this.


Does SharePoint have to be internet facing when connecting to dynamics-crm Online

Question: Hi I'm trying to find some information at to weather SharePoint 2010 installed on prem needs to be available over the internet to integrate with dynamics-crm online
Thanks in advance
Answer: Well basically you need to have access to Dynamics CRM Online or it's webservices, so you need to have internet access.
But what you can do is develop a small integration platform as a console application that can access both your sharepoint farm and Dynamics CRM Online
Comment: Thanks, maybe i could be a little more clearer. Communication  from SharePoint to CRM should be fine as we have internet connection on prem however SharePoint does not have any public facing urls, its intranet only. My understanding is that to access SharePoint documents from within CRM online, CRM needs to have some connectivity to SharePoint be it via internet. Is it possible to not expose on SharePoint intranet over the internet and implement some bridge connection from CRM to SharePoint?
Comment: Okay, so you are talking about the opposite direction. I would say that that fact does not change my answer. You will still need to create some form of integrations layer