Why is "christou" translated "God" in KJV Romans 10:17?

Question: I was actually looking up the verse for another question I might ask about rhema (actually rēmatos) "hearing, and hearing by..." but I noticed that though I had memory of it saying "the word of God", it clearly shows "the word of Christ" if the concordances are correct. Is there a good argument for using "God" instead or "Christ" or "The anointed" here?
Answer:
Why is "christou" translated "God" in KJV Romans 10:17?

It isn't. The text base used for the KJV was primarily the 1588/89 and '98 editions of Theodore Beza, occasionally departing to follow Stephanus's 1550 Novum Testamentum. These read:1

αρα η πιστις εξ ακοης η δε ακοη δια ρηματος θεου

This was correctly translated in the KJV  ...the word of God. In contrast, the NA-28:

ἄρα ἡ πίστις ἐξ ἀκοῆς, ἡ δὲ ἀκοὴ διὰ ῥήματος Χριστοῦ.
  So faith comes through hearing and hearing through the word of Christ.

The reading Χριστοῦ (of Christ) has broad and early attestation including Papyrus 46; Codices Sinaiticus and Vaticanus; and the Latin (Vulgate and Old Latin), Coptic, and other early versions. Stephanus's and Beza's text is that of Alexandrinus, the Byzantine witnesses, several miniscules, and a later correction of Sinaiticus that read instead ...ρηματος θεου (...the word of God).2
Modern critical editions (SBL, UBS4, and NA28) indicate that διὰ ῥήματος Χριστοῦ is the superior reading. The UBS committee indicated their certainty of this choice with an {A} rating. Their reasoning was presumably due mostly to the nature of the witnesses. In addition, as recorded by Metzger:3

The expression ῥῆμα Χριστοῦ occurs only here in the New Testament, whereas ῥῆμα θεοῦ is a more familiar expression

He points out that ρημα θεοῦ occurs at Lk 3:2; Jn 3:34; Eph 6:17; and Heb. 6:5, 11.3. Scribes may have been inclined to change the less familiar δια ρηματος Χριστου to the more familiar δια ρηματος θεου.

1. Linked is the text of Beza's 1598/1599 edition, courtesy of The Center for the Study of New Testament Manuscripts. Next to the Greek text are two parallel columns of Latin. The middle column agrees with the Greek (per verbum Dei); the final column (per verbu(?) Christi) is consistent with the Vulgate. Commentary on the discrepancy is found in Latin at the bottom of the page for the interested Latin reader.

2. Barbara Aland et al., eds., The Greek New Testament (4th ed.; Stuttgart: Deutsche Bibelgesellschaft, 2001), 61.

3. Bruce M. Metzger, A Textual Commentary on the Greek New Testament (New York: United Bible Societies, 1994), 464.
Answer: Romans 10:17:  "So then faith cometh by hearing, and hearing by the Word of God" (KJV), or "So faith comes from hearing, and hearing by the word of Christ" (NASB)?
James made note that faith in God was not something special: "You believe that there is one God. Good!  Even the demons believe that — and shudder" (James 2:19, NIV).
Salvation comes through Jesus Christ.  Those that confess Christ before men, he will confess them before the Father and His angels.
The dispute is between the Word "Rhema" of God as translated in the KJV versus the Word "Rhema" of Christ.  Rhema or ῥῆμα in Greek, literally means an "utterance" or "thing said". It is a word that signifies the action of utterance.
The KJV primarily follows the Byzantine text or Textus Receptus "received text" of Erasmus.  The name given to the succession of printed Greek texts of the New Testament which constituted the translation base for the original German Luther Bible, the translation of the New Testament into English by William Tyndale, the King James Version, the Spanish Reina-Valera translation and most other Reformation-era New Testament translations throughout Western and Central Europe.
The series originated with the first printed Greek New Testament, published in 1516 – undertaken in Basel by the Dutch Catholic scholar and humanist Desiderius Erasmus. Although based mainly on late manuscripts of the Byzantine text-type, Erasmus' edition differed markedly from the classic form of that text, and included some missing parts back translated from the Latin Vulgate.
The Latin Vulgate is largely the work of St. Jerome, who, in 382, translated Rom.10:17 as: "ergo fides ex auditu auditus autem per verbum Christi" - or word of Christ.  Luther's German Bible offered the same: "So kommt der Glaube aus der Predigt, das Predigen aber durch das Wort Christi" - or Word of Christ.  All of the following also offer "word of Christ":

Nestle Greek New Testament (1904): "ἄρα ἡ πίστις ἐξ ἀκοῆς, ἡ δὲ ἀκοὴ
διὰ ῥήματος Χριστοῦ."
Nestle's latest version 28:  "ἄρα ἡ πίστις ἐξ ἀκοῆς, ἡ δὲ ἀκοὴ διὰ
ῥήματος Χριστοῦ."
SBL Greek New Testament (2010): "ἄρα ἡ πίστις ἐξ ἀκοῆς, ἡ δὲ ἀκοὴ διὰ
ῥήματος Χριστοῦ."
Westcott and Hort (1881): "ἄρα ἡ πίστις ἐξ ἀκοῆς, ἡ δὲ ἀκοὴ διὰ
ῥήματος Χριστοῦ."
Westcott and Hort / [NA27 variants]: "ἄρα ἡ πίστις ἐξ ἀκοῆς, ἡ δὲ
ἀκοὴ διὰ ῥήματος Χριστοῦ."
Tischendorf 8th Edition: "ἄρα ἡ πίστις ἐξ ἀκοῆς, ἡ δὲ ἀκοὴ διὰ
ῥήματος Χριστοῦ."

Personally I support the usage of Word of Christ, because this particular verse refers to where faith comes from.  Obviously the entire Bible is the Word of God and Jesus is the Logos of God; Romans 10:17 refers specifically to the spoken word "rhema" of Christ. There are other verses in the Bible that refer to the Word "rhema" of God, but not every word is spoken by or about Christ, as a matter of fact Jesus did not write anything down that we know of other than some words in the sand.  He spoke the fullness of Word of God, and as such they were his words remembered and written down by his Apostles and Prophets inspired to do so by the Holy Spirit; as was the TANAKH.  However, if the OT was able to save it's hearers there would have been no need for a New Covenant; and Jesus need not have come, suffered and died fulfilling all the Law and Commandments. So faith comes through hearing and hearing the Words of Christ.

"But how can people call for help if they don't know who to trust? And how can they know who to trust if they haven't heard of the One who can be trusted? And how can they hear if nobody tells them? And how is anyone going to tell them, unless someone is sent to do it?" (Rom.10:14, The Message),

"Does anyone care? Is anyone listening and believing a word of it?" The point is: Before you trust, you have to listen. But unless Christ's Word is preached, there's nothing to have faith in.  The Law cannot give faith.  Faith comes through faith in Christ Jesus.
Comment: Welcome to Biblical Hermeneutics Stack Exchange, thanks for contributing! Be sure to take our [site tour](http://hermeneutics.stackexchange.com/tour) to learn more about us. [We're a little different from other sites.](http://meta.hermeneutics.stackexchange.com/a/803/423)
Comment: I've attempted an *Edit* to add some formatting to help clarify the emphasis of your answer somewhat, to try and improve readability. Have a look and make any corrections if I've interpreted anything incorrectly.
Answer: You are right when you say this particular verse (Rom 10:17) refers to faith's origin, but the words that Paul is using come from the Septuagint version of Isa. 53:1 where κυριε refers to YHWH; hence "word of God" is appropriate here.
This phrase - λογοv θεου - appears more than 30x throughout the NT Rom. 10:17 is the only instance of ρηματοζ Χριστου in the NT. I think the only other use of "word of Christ" is Col 3:16 - λογοσ τοθ Χριστου - obviously reading what it says.
Comment: Hi Bruce, welcome to BH-Stack Exchange, we are glad you are here. Please be sure to take the [site tour](https://www.hermeneutics.stackexchange.com/tour) and read our [code of conduct](https://www.hermeneutics.stackexchange.com/conduct). Thanks!
Answer: The Luther bible has "So kommt der Glaube aus der Predigt, das Predigen aber aus dem Wort Gottes."
Comment: The OP is asking about the use of "Christ" in the KJV. Can you please provide additional information as to your answer referencing the Luther Bible? Welcome to Bible Hermeneutics SE and thank you for your contribution. Also, when you get a chance, please take the [tour] to understand how the site works and [how it is different than others](https://hermeneutics.meta.stackexchange.com/questions/653/how-can-we-educate-new-users-about-our-site-distinctives/803#803).
Comment: For the non-German readers among us, can you please [edit] this to explain what that means and how it helps explain why the KJV was translated as it was?


Is there any other use-case of having a decentralised network other than majorly DeFi and GameFi?

Question: I have been familiar with the Web3 ecosystem for almost 2-years now. But I still fail to understand if there is any other real world use-case for a decentralised network other than DeFi, ICOs and NFTs for maybe some games (GameFi) or some raw artwork. Even GameFi isn't fully decentralised. It actually hosts servers on AWS/GCP/Azure and only uses decentralised networks for primarily NFTs. I agree that I am still learning a lot about the space, but I really want to get into some other kinds of projects where web3 could potentially be leveraged.
Answer: You can find the case studios of public blockchain real-world use cases at ValueProp database.


What is the difference between a mouseover and a hoverover?

Question: I have seen both a 'mouseover' and a 'hoverover' referring to the same thing - but it is not clear if there is a difference.
Is there a functional difference between the two terms, or are they identical in meaning?
Comment: How is this a UX question?
Answer: From documentation

mouseover(): source

Bind an event handler to the "mouseover" JavaScript event, or trigger that event on an element.
Meaning only when the mouse is over an element.

.hover(): source

Bind one or two handlers to the matched elements, to be executed when the mouse pointer enters and leaves the elements.
Calling $(selector).hover(handlerIn, handlerOut)

is shorthand for:
$(selector).mouseenter(handlerIn).mouseleave(handlerOut);
A lot of times, these terms are used together because they describe what should happen when a user places their mouse over an element. How will this element look like? But if you want to talk to a developer, it is nice to know the difference.
This is a good explanation with examples

The hover() function is more high level - it's built to call functions
  to handle both a mouseenter event and a mouseleave event. It's very
  convenient for a UI element that has a hover and normal state (e.g. a
  button.)
The mouseover() function specifically binds to the mouseover event.
  It's best for situations where you only care when the mouse has
  crossed the border into an element and you don't really care what
  happens if it leaves. It's also the function to call when you want to
  trigger the event on some element.

From Quora
Comment: Good answer. Alas - it is only good for JQuery.
Answer: Is there a functional difference between the two terms, or are they
identical in meaning?
I think it depends upon who is talking. Most end users will use them interchangeably - which makes sense. As a non-techie a mouseover is basically hovering over the item which causes some "thing" to happen.
However, to someone who write javascript, the two have different meanings.

The .hover() method binds handlers for both mouseenter and mouseleave events. You can use it to simply apply behavior to an element during the time the mouse is within the element.

See: api.jquery.com/hover/


Are my cluster means significantly different?

Question: I have just performed a K-means clustering analysis on 43 variables and as a result I have 2 cluster. Now I want to test if the cluster means for each variable are significantly different between the 2 clusters. Rather then doing 43 individual t-tests, is there a better way to test statistical significance in this case?
Comment: You can do MANOVA and what not.. But what is the reason? Because clustering (classic methods such as k-means) by definition will split your data into nonoverlapping groups those groups are expected to differ "significantly" by many if not all of the attributes used in the clustering.
Answer: It's deceptive to perform this kind of tests. You'd need to perform some clever cross validation, such as using only 42 attributes for clustering, then testing the withheld attribute.
Because if you use the same attributes/samples for clustering and for splitting, this will overfit. You can get highly "significant" differences even on random data.
See the discussion of the **Calinski-Harabasz Variance-Ratio-Criterion ** on why you can't just apply the usual significance thresholds here.


tracking clicks from edm to conversion

Question: I need to track click-thru on my edm, and i need to see how many of these click-thru actually convert (within 30 days) at the end of the day.

So my idea is, on every link on the edm, i point them to my domain (siteA.com), where i set a cookie, then redirect them to the actual site where they initially clicked on (siteB.com).
The user then clicks on buy now and gets sent to the purchasing site (siteC.com).
On the purchase confirmation page, i call a script that resides on siteA.com, to grab the cookie that i set (if any) and logs the transaction.

So far, i managed to get to step 3, where it calls the script residing on siteA.com, but i am unable to get the value of the cookie that i set earlier. I know that it called the script, because the log file gets written to with the transaction details, but no cookie details. Am i using the wrong callback to the script on siteA.com? Or am i missing something totally?
So this is the code i'm using on the confirmation page:

on the tracking.php file, i have the following javascript code:
function logTransaction (orderValue , orderRef, merchantID, uid , htname, pixel, payoutCodes, offlineCode,checkOutDate,currencyCode)
{
    var xmlhttp;

    if (window.XMLHttpRequest){// code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp=new XMLHttpRequest();
    }
    else{// code for IE6, IE5
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    }

    xmlhttp.open("GET","http://siteA.com/tracker/confirmation.php?tranID="+uid+"&orderValue="+orderValue+"&currencyCode="+currencyCode,true);
    xmlhttp.send();
}

and finally, this is what i have on the confirmation.php
if (isset($_COOKIE["myedm"])) {
    $cookie_array = explode(",", $_COOKIE["myedm"]);
    $mc_cid = $cookie_array[0];
    $mc_eid = $cookie_array[1];
    $numberofvisits = $cookie_array[2];
}

$tranID = $_GET['tranID'];
$orderValue = $_GET['orderValue'];
$currencyCode = $_GET['currencyCode'];

$file = 'people.txt';
// Open the file to get existing content
$current = file_get_contents($file);
// Append a new person to the file

$current .=  "\n tranID:".$tranID;
$current .=  "\n currencyCode:".$currencyCode;
$current .=  "\n orderValue:".$orderValue;

$current .=  "\n mc_cid:".$mc_cid;
$current .=  "\n mc_eid:".$mc_eid;
$current .=  "\n numberofvisits:".$numberofvisits;

// Write the contents back to the file
file_put_contents($file, $current);

Answer: Update:
I fixed the problem.. kind of..
changed the javascript calling the file to using a img pix, i.e.

it works! but only in firefox n chrome. In IE, doesn't seem to want to set the cookie even..

tracking clicks from edm to conversion


Why adjoining non-Archimedean element doesn't work as calculus foundation?

Question: Consider the smallest ordered field that contains R and does not satisfy the Archimedean property. I assume this is a much simpler construction than ultrafilters and other big caliber artillery used in non-standard analysis. Why does this approach fail?
Comment: @Arturo, sure, and there's a concrete construction in the article. Without checking all the details, it looks like the fraction field of $\mathbb Q[X]$, equipped with an appropriate ordering.
Comment: @All: the context of the article seems to be the construction of a field which is an initial object in the category of ordered fields equipped with a distinguished non-Archimedean element.  It is of course not true that there is a smallest non-Archmidean ordered field, because if $K$ is such a field and $x$ is a non-Archimedean element of $K$ then $\mathbb{Q}(x^2)$ is a strictly smaller non-Archimedean field.
Comment: @Henning: You would still need to establish somehow that such a thing exists in the first place. This does not seem to be something you can simply "define into existence".
Comment: @Arturo, it contains the claim: "if $\mathbb{F}$ is any ordered field that fails the Archimedean property and $y$ is any positive element of $\mathbb{F}$ that is smaller than every $1/n$, then there is a unique field embedding from $\mathbb{Q}[x]$ to $\mathbb{F}$ that takes $x$ to $y$. This gives us a precise sense in which our example is "smallest"."
Comment: @Henning: If there is a construction, and the construction pans out, fine; but it needs to go beyond merely stating "the smallest a such that b..."
Comment: "Smallest" in what sense? Inclusion? How do you know there is a "smallest" such field?  Maybe I can have two ordered fields $F$ and $F'$ that contain $\mathbb{R}$ and don't satisfy the archimedean property, but with $F\cap F'=\mathbb{R}$; which one is smallest, then? (And it's easy to see that if there is *one* field $F$ that is ordered, contains $\mathbb{R}$, and does not satisfy the Archimedean property, then one can find an $F'$ that also has those properties and intersects $F$ at exactly $\mathbb{R}$ by using [transport of structure](http://en.wikipedia.org/wiki/Transport_of_structure)).
Comment: How about field extension of R adjoining just a single non-Archimedean element?
Comment: @Arturo: You might want to specify that $F$ and $F'$ are *not isomorphic* as well.
Comment: @Arturo, a quick glance at the linked article suggests to me that the field in question is asserted to be "smallest" with respect to the existence of injective field homomorphisms, not by set inclusion.
Comment: @Tegiri: Field extensions obtained by adjunction are defined as subfields of a specific extension; what extension are you considering so that you can talk about "adjunction by a single element"? Or else they are defined as specific quotients of explicit objects. Which object/quotient will give me your construction? I can define "the opensure" of a subset $X$ of a topological space to be the smallest open subset that contains $X$. Doesn't mean that $[0,1]$ has an opensure in the usual topology of the real line, though.
Comment: @Henning: At best, the article is attempting to define a *minimal* structure, without asserting it is a *minimum* structure.
Comment: @Tegiri: You would be defining a transcendental extension of $\mathbf{R}$. That would not be real closed field (=all the odd degree polynomials must have a root). So e.g. Bolzano's theorem would fail. Consequently we would also be in the situation of Henning's answer: you would not get an algebraically closed field by adjoinins $\sqrt{-1}$.
Comment: @Pete: it's only smaller as measured by $\subseteq$, which is probably not the measure we want. There's an ordered field isomorphism $\mathbb{Q}(x^2) \to \mathbb{Q}(x)$, for example.
Comment: @Hurkyl: I agree.
Answer: To perform nontrivial analysis in a nonstandard extension of $\:\mathbb R\:$ requires much more than simply the existence of infinitesimals. One needs some efficient general way to transfer (first-order) properties from $\:\mathbb R\:$ to the nonstandard extension. This is achieved by a powerful transfer principle in NSA. Lacking such, and other essential properties such as saturation, one faces huge obstacles.
One need only examine earlier approaches to see examples of such problems. For example, see the discussion of the pitfalls of Schmieden and Laugwitz's
calculus of infinitesimals in Dauben's biography of Abe Robinson
(lookup "Laugwitz" in the index) and, for much further detail, see D. Spalt: Curt Schmieden's Non-standard Analysis, 2001. In short, viewed in terms of
ultrapowers $\mathbb R^\mathbb N,\:$ the S&L approach mods out only by a Frechet filter on $\mathbb N\:$ instead of a free ultrafilter. Thus one loses full transfer of first-order properties, e.g. one obtains only a partially ordered ring, with zero-divisors (i.e. there are $r,s\neq 0\,$ with $rs = 0)$. Without all of the essential properties of $\mathbb R,\:$ and without a general transfer principle, one obtains a much weaker and much more cumbersome theory as compared to  Robinson's NSA.
Another point which deserves emphasis is the role played by logic, in particular the concept of formal languages. One of the major problems with early approaches to infinitesimals is that they lacked rigorous model theoretic techniques. For example, without the notion of a (first-order) formal language
it is impossible to rigorously state what properties
of reals transfer to hyperreals. This logical inadequacy is one of the primary sources of contradictions in the earlier approaches.
Abraham Robinson wrote much on these topics. It is said that he knew more about
Leibniz than anyone. His lofty goal was to vindicate Leibniz'
intuition, and to reverse the historical injustices done to
him by many Whiggish historians. See Abby's collected papers
for much more, and see also Dauben's superb biography of Robinson.
For a brief introduction to the ultraproduct approach to NSA see Wm. Hatcher: Calculus is Algebra, AMM 1982, and Van Osdol: Truth with Respect to an Ultrafilter or How to make Intuition Rigorous. For a much more comprehensive introduction to ultraproducts see Paul Eklof. Ultraproducts for Algebraists, 1977.
Comment: Thank you for "Schmieden and Laugwitz's calculus of infinitesimals" which brings up many online references, e.g. http://www.gauge-institute.org/delta/InfinitesimalCalculusT.pdf
Comment: @Teg See the link I added to Spalt's paper for a  nice accessible introduction to these topics.
Comment: @BillDubuque, I tried to provide a detailed answer.
Answer: The heavy artillery of the model-theoretic approach to non-standard analysis is doing much more than just producing any one non-Archimedean ordered field or even a non-Archimedean ordered field which is elementarily equivalent to $\mathbb{R}$ (an ordered field is elementarily equivalent to $\mathbb{R}$ iff it is real-closed, so starting with any non-Archimedean ordered field, e.g. $\mathbb{R}(t)$, and taking the real-closure produces such a field).  There is an elaborate machinery of transfer, standard parts, etc. to overcome the fact that calculus does not work as we want it to in any non-Archimedean ordered field.
Note that the unique (up to unique isomorphism!) Dedekind-complete ordered field is $\mathbb{R}$, so any other ordered field is not Dedekind-complete.  More directly, if $K$ is a non-Archimedean ordered field, then the set of positive integers is bounded above (by any infinite element of $K$) but has no least upper bound, so $K$ is not Dedekind complete.  This spells doom for many of the basic results of real analysis.
For instance, for an ordered field $(K,\leq)$, the following are equivalent:
(i) $K$ is isomorphic to the real numbers.
(ii) $K$ satisfies the least upper bound axiom (i.e., $K$ is Dedekind complete).
(iii) Any bounded monotone sequence in $K$ is convergent.
(iv) (Bolzano-Weierstrass) Every bounded sequence in $K$ has a convergent subsequence.
(v) Any interval in $K$ is connected in the order topology.
(vi) Any closed bounded interval $[a,b]$ is compact in the order topology.
So working in a non-Archimedean field -- and not using model-theoretic cleverness to carefully restrict to certain kinds of statements -- calculus as we know it fails dramatically.
Answer: The construction you link to will work as far as it goes, if your only goal is to produce some non-Archimedian ordered field. However, the model-theoretic construction is much stronger; it will guarantee that every formal statement that is true about the standard reals is also true for the non-standard reals, as long as you replace all constants in the statement with their non-standard counterparts. Without this, it could be difficult to transfer results between the standard and the non-standard worlds.
For example, if one takes your simpler construction and adjoins a square root of $-1$, will the resulting field satisfy the Fundamental Theorem of Algebra? You would have to repeat the entire proof from the real case, if it goes through at all. With the heavy-caliber nonstandard analysis, you can just says that every nonconstant degree-$n$ polynomial over $\mathbb C$ has a root in $\mathbb C$, thus every nonconstant degree-$n$ polynomial over $\mathbb C^*$ has a root in $\mathbb C^*$. Case closed.
Comment: I don't think it is a sensible definition, myself... if you use inclusion as your order relation, then there is no such thing in general and you would first need to show you can make it work (say, by working inside some specific field, much like we do with "Galois closures"); if you use "there is an injective homomorphism" as your order relation, you need to show that there is a minimum element of the collection...
Comment: Um, what is not a sensible definition? _I'm_ not defining anything here -- I'm assuming that the reader knows what the heavy-caliber ultrafilter stuff does, and just explaining how that makes it superior.
Comment: Sorry for being unclear; I don't think "The smallest ordered field that contains $\mathbb{R}$ and does not satisfy the Archimedean property" is a sensible definition. By saying "it will work as far as it goes", you seem to be saying that this definition *is* sensible.
Comment: That's what I get for not reading through pages of stuff; the original post here reads like it attempts to define this thing into existence by simply saying the magic words. Sorry about that.
Comment: When you say "every formal statement" I guess you are referring to Łoś' theorem -- so you need to restrict to  *first order* statements only.  The hyperreals $^* \mathbb{R}$ don't satisfy the (second order) completeness axiom for example (a good thing too, otherwise they'd be isomorphic to the reals again).
Comment: @mt, yeah, I'm doing first-order logic by default, and not in the habit of pointing that out explicitly. The development I have the clearest recollection of created an entire non-standard set theory anyway...
Comment: Is this really an answer to the OP's question?  Shouldn't one say something about *why* calculus breaks down for non-Archimedean fields like $\mathbb{Q}(t)$?  Also, of course the field $\mathbb{Q}(t)[\sqrt{-1}]$ does not satisfy the fundamental theorem of algebra: the algebraic closure of $\mathbb{Q}(t)$ has infinite degree over $\mathbb{Q}(t)$, as one can see already by noting that the polynomials $x^n - t$ are all irreducible.
Comment: @Pete, if you can write a more complete answer, by all means do so. I'm not claiming a monopoly on the question. :-)
Comment: For more or less the simplest use of such an extension field $\mathbb{R}^\ast$, we need, for *every* differentiable function $f$ on $\mathbb{R}$ an extension $f^\ast$ to $\mathbb{R}^\ast$ with the property that for any infinitesimal $\epsilon$, the standard part of $(f^{\ast}(x+\epsilon)-f(x))/\epsilon$ exists and is equal to $f'(x)$.  This is a very strong requirement. Sure, we need failure of the Archimedean property, but we need enormously more.
Comment: Why Fundamental theorem of algebra is needed in calculus, i.e. where irreducibility of x^^n-t matters?
Comment: @Tegiri: well, for instance, the Intermediate Value Theorem holds for all polynomials with coefficients in an ordered field $K$ iff $K(\sqrt{-1})$ is algebraically closed.
Comment: @Tegiri, FTA was a more or less arbitrary example of a property you might want to use in the non-standard world. It tends to crops up everywhere if you dig a bit for it. As a single just-as-arbitrary example, if you're doing vector analysis, sooner or later you'll probably want to look for roots of the characteristic polynomial of a Jacobian matrix.
Comment: Sorry to be obtuse but isn't Intermediate Value Theorem scope is any function, not just polynomial? Is there a more elementary counterexample (copmpared to Jacobian matrix). If you demonstrate, say, that there is a problem finding derivative of a square function (or any other derivatives rule for that matter), than it is much more convincing:-)
Comment: @Tegiri: right, so whether IVT holds for polynomials only is a weaker property of the field.  (But there are branches of mathematics in which one is interested primarily in polynomial functions, e.g. **real algebraic geometry**.)  Related to my answer, IVT holds for all continuous functions over an ordered field $K$ iff $K \cong \mathbb{R}$.
Answer: If the assumption of the question is that using a simple-minded non-Archimedean field cannot be used to get interesting mathematical results, that assumption can be challenged.  For example, Dehn used a simple-minded non-Archimedean field to resolve one of Hilbert's famous problems; see here.
Comment: Yes, it is clear now that you are interpreting the question "why does this approach fail" more generally than the scope given in the title ("doesn't work for *calculus foundations*").
Comment: Note that the title refers to it working for "calculus foundations*, not "interesting mathematical results".  But no doubt other applications may also be of interest to readers.
Comment: @BillDubuque, the OP's concluding question is  "Why does this approach fail?"  This question is what my answer is a response to.


Girl discovers she is psychic and an experiment

Question: I read a book back in the '90s about a school-aged girl who runs into another girl who looks exactly like her and is apparently killing people with psychically induced heart attacks. The main character finds out that she also has psychic powers (she figures this out when she comes under attack and constructs a "wall" in her head to stop it) and is one of multiple girls from an experiment. Any idea what it could be? I've been hunting for any kind of clues about it for ages now. I though it might have been an RL Stine book, but couldn't find any that match the description.
Answer: Is it Eve from the X Files novel series? It fits some of the criteria (90s, girl from experiments) but I think the killing was with digitalis rather than through psychic powers.
Comment: It's not X Files unfortunately, I wish it had been that easy. It would be what we consider today to be a Young Adult book. I know it's not Replica either, because not only do I still own some of those, but none of the girls in that one had psychic powers.


SMTP and POP3 Restriction

Question: My Network administrators decided to disable SMTP and POP3 ? I can't use Outlook, Apple Mail or Thunderbird ? is there a way to get around this ?
Comment: use a tunnel with putty over port 443 to a ssh server outside for example at your home...
Comment: use web clients, I guess
Answer: If they have disabled it, its most likely for a reason. So you probably will get no help here from the folks who put those policies in place.
Comment: Right. From the FAQ, this site is for system admins. You're not one, you're trying to get around the folks who admin your company's systems. Talking with management and/or the sysadmin team about this.
Answer: You can use SOCKS or HTTP proxy.

SMTP and POP3 Restriction


Wiring question

Question: I just had my house painted. The painters took down the exterior lights. When they hooked them back up, the circuit breaker kept tripping when I turned the exterior light switch on. I took the fixture off and found that the ground wire from the fixture had been secured with the wire nut to the black (live) wires. I rewired it the way I had originally wired it (black to black, white to white, and ground to the ground screw) and it will not work. It does not trip the breaker anymore, but it seems as though the light fixture is ruined. Would that ruin the light fixture?
Comment: Bench test the fixture in a separate location, e.g. with a cheater cord made from a cutting the socket off an extension cord.
Comment: It probably did not break from that misconnection. Get a multimeter and use its ohmmeter feature to check for continuity from the input prongs to the sockets. This assuming your fixture isn't one with built-in ballast or something more complex.
Comment: It's not totally clear to me what you're asking, but if you're asking whether the incorrect wiring alone could have broken the lamp, my guess is no. If it's a halogen lamp (you didn't say what kind it is), then they probably knocked it about; look at the bulb to see if the filament is broken. If it's LED or CFL based, you're probably not going to be able to tell what broke just by looking.
Comment: I am more asking if by hooking the ground wire to the live wire it ruined the whole fixture. The bulbs are good. I tested them in a different light fixture.
Comment: Did you try a new lamp?
Answer: Check for a tripped GFI receptacle somewhere.
Miswiring a simple lamp fixture shouldn't ruin it.

Wiring question


Geolocate service I can use?

Question: I can access very accurate geolocate info from Google Analytics, but is there any way to access the geolocate information of Google or otherwise for an IP address, from a computer program, like a web ervice or something? I know there is "whois" but I would like something a little less hassle.
Comment: Obligatory XKCD link: http://xkcd.com/713/
Answer: One of the best options I have found for doing this is MaxMind city GeoIP data. They have an API and a free lite version you can get started with as well.
Answer: There's http://www.geobytes.com/IpLocator.htm which gives 20 IP lookups / hour.  Generally IP lookups are not so accurate (they map to the ISP), and most HTML5-capable browsers can read the location.
Comment: When I used this service, if the site owner forgot to pay for more look-ups, it would interject a page of their choosing every so often.  To me, that was much **much** worse than just not working.
Comment: Well a site-owner has to gauge how many requests will be needed, and pay for extra request as needed.  However that is pretty bad.

Geolocate service I can use?


Likelihood - Why multiply?

Question: I am studying about maximum likelihood estimation and I read that the likelihood function is the product of the probabilities of each variable. Why is it the product? Why not the sum? I have been trying to search on Google but I can't find any meaningful answers.
https://en.wikipedia.org/wiki/Maximum_likelihood
Comment: Note that this is not necessarily the case, and in general the maximum likelihood is defined in terms of the joint density of the random variables. Of course if they are independent their joint density is just the product of the marginals
Comment: say you have a 80% probability of having brown hair, and a 75% probability of having brown eyes. Do you think it is possible that the probability of being brown-haired **and** brown-eyed is `80% + 75% = 155%`? how about `80% * 75% = 60%`?
Comment: Remember that multiplying is just a shorthand for addition.  When I say 2 times 3 I'm saying 2+2+2.  We multiply because we're lazy.  Who has time to do it the hard way?  You can add if it helps you see what's going on (helped me understand the Monty Hall problem) but after a while you'll get bored with it.
Answer: This is a very basic question, and instead of using formal language and mathematical notation, I will try to answer it at a level at which everybody who can understand the question can also understand the answer.
Imagine that we have a race of cats. They have a 75% probability of being born white, and 25% probability of being born grey, no other colors. Also, they have a 50% probability of having green eyes and 50% probability of having blue eyes, and coat color and eye color are independent.
Now let us look at a litter of eight kittens:

You will see that 1 out of 4, or 25%, are grey. Also, 1 out of 2, or 50% have blue eyes. Now the question is,

how many kittens have grey fur and blue eyes?

You can count them, the answer is one. That is, $\frac{1}{4} \times \frac{1}{2} = \frac{1}{8}$, or 12.5% of 8 kittens.
Why does it happen? Because any cat has a 1 in 4 probability to be grey. So, pick four cats, and you can expect one of them to be grey. But if you only pick four cats out of many (and get the expected value of 1 grey cat), the one which is grey has a 1 in 2 probability to have blue eyes. This means, of the total of cats you pick, you first multiply the total by 25% to get the grey cats, and then you multiply the selected 25% of all cats by 50% to get those of them which have blue eyes. This gives you the probability of getting blue-eyed grey cats.
Summing them up would give you $\frac{1}{4} + \frac{1}{2}$, which makes $\frac{3}{4}$ or 6 out of 8. In our picture, it corresponds to summing up the cats which have blue eyes with the cats which have grey fur - and counting the one grey blue-eyed kitten twice! Such a calculation can have its place, but it is rather unusual in probability calculations, and it is certainly not the one you are asking about.
Comment: This answer is actually flawed, because it still conflates observed value and expected value. Seeing how popular it is, I will try finding the time to  update it with an explanation why this way of subsetting the cats gives us a maximum likelihood estimator (or, resolving the problem of picking 8 random cats and finding out that they are not the ones I painted in the picture).
Comment: I am aware that the other answers here mean the same thing. Still I think that a visual representation is needed here - if the OP was able to visualize the concept himself, he probably would have arrived at the answer already.
Comment: This is actually a terrific answer as it shows each independent variable as an independent axis in the cat matrix. This makes it very easy to understand. I'll be using this example to teach my children!
Comment: Why can't this be the entire population of such cats?  (Say they have some special research property -- their tongues are chemiluminescent, for instance.)  Then the conflation is non-deleterious.
Answer: Independence between two events means that the occurrence of one event does not affect the likelihood of the occurrence of the another event . So for any two events $A$ and $B$ in a sample space $S$  we say that $A$ and $B$ are independent  iff $P(A$ and $B)=P(A\cap B) = P(A)P(B)$ .Now for more than two events we say that the events $A_1,A_2,...A_n $ are independent iff $P(\underset{i\in I}{\cap A_i})= \prod_{i\in I} P(A_i)$ for all subsets $I \subset [1,2,...,n]$ .
In the likelihood we suppose that there is a sample $x_1, x_2, …, x_n $of $n$ independent and identically distributed observations (iid), coming from a distribution with an unknown probability density function , that means this joint density function is
$f(x_1,x_2,...,x_n|\theta) = \prod_{i=1}^{i=n}f(x_i|\theta)$.
Comment: So is it correct to assume that whenever we use maximum likelihood estimates, we are assuming iid for our observations?
Comment: The correct notation for the joint density function representing the likelihood wouldn't be $f(x_1,x_2,...,x_n;\theta) = \prod_{i=1}^{i=n}f(x_i;\theta)$?

I guess this ";" is used to not confuse with the bayesian version.
Answer: Under the common assumption of independence, $P(A \cap B)$ = $P(A) P(B)$.
Thus, if you assume that all your observations are independent, then the probability of observing all the values you saw is equal to the product of the individual probabilities.
Comment: I think it would help the OP if you also explain why $P(A \cap B)$ is of interest here.
Comment: @HaziqRazali A question like "why maximize likelihood" is a new question (one that has been asked and answered elsewhere on the site)
Comment: Hi thanks for the reply ! Why do I maximize the likelihood (joint density function) ? Why can't I instead maximize the sum of the probabilities of all observation (or any other function) ? I would like to find the reason why the joint density function is chosen.

Wikipedia starts off by using the joint density function. But is there a reason why we use the joint density function ? This is what I have been trying to understand.
Comment: @haziqRazali the idea of MLE is to pick the estimates so as to the make the sample you have most likely given the distribution. Hence the name maximum likelihood
Answer: Why not add?
Because that clearly makes no sense.  Suppose you have a quarter and a nickel, and you want to flip them both. There's a 50% chance the quarter will come up heads, and a 50% chance the nickel comes up heads.  If the chance of both coming up heads were the sum, that would make 100% chance, which is obviously wrong, as it leaves no chance for HT, TH, and TT.
Why multiply?
Because it does make sense.  When you multiply the 50% chance of the quarter coming up heads by the 50% chance of the nickel coming up heads, you get 0.5 x 0.5 = 0.25 =25% chance of both coins being heads.  Given that there are four possible combinations (HH, HT, TH, HT) and each is equally likely, this fit perfectly.  When evaluating the likelihood of two independent events both occurring, we multiply their individual probabilities.
Answer: I am reading these posts because, like the Original Poster, my need is to understand why the 'Likelihood' fn is the 'Product' of the density of each sample value -'x'.
A readable and logical reason is given under the heading Principle of maximum likelihood Ref:
http://www-structmed.cimr.cam.ac.uk/Course/Likelihood/likelihood.html
A further quotation Mathematically, the likelihood is defined as the probability of making the set of measurements  (same ref.)
In short, the probabilty that you arrived at the sample that you have at hand.
Answer: The goal of the maximum likelihood method is find estimator that maximize the probability of observe certains values of the variable ( endogenous variable). That is the reason why we must multiply the probabilties of ocurrence.
For example: imagine that the numbers of phone calls that a secretary can answer in an hour follows a poisson distribution. Then, you extract 2 values of the sample ( 5 phone calls and 8 phone calls per hour)
Now you must answer this question. What is the value of the parameter that maximize the probability of observe 5 and 8 phone calls, simultaneously?. After, try to answer with the probaility of observe all the values of the sam
Due to the independant random variables,
f(y1 = 5 phone calls)*f(y2 = 8 phone calls) = ∏i f(y,θ) = L(θ,y1,y2)
Finally, try to answer, the probability of observe all the values of the sample.
Answer: In practice, when we want to find MLE we would usually take the log of the likelihood function. Then the product of density function or probability (depend on the data type) shall become sum.
As to the question why likelihood is a product of probability. Considering  "The goal of maximum likelihood estimation is to find the values of the model parameters that maximize the likelihood function over the parameter space", we want to maximize the likelihood and a best estimate is the probability. Suppose there is a normal distribution with parameters $\mu$ and $\sigma^2$, response Y, $x_i$ are independent, then $L(\mu, \sigma^2 | Y) = P(y | \mu, \sigma^2)$. Because probability of independent events $P(A\cup{B}) = P(A)P(B)$. The likelihood becomes the product of the probability.

Likelihood - Why multiply?


How to see what command-line options handbrake sends to mencoder

Question: I want to see what command-line options handbrake is sending to mencoder. I looked at the Activity Window and it shows a lot of stuff but not what I'm looking for. How can I find it?
Comment: at least under windows handbrake is not using mencoder. it uses libs from ffmpeg and other projects, but not the mencoder binary as far as i can see it. it uses HandBrakeCLI.exe
Comment: Using OSX. Someone said that Handbrake was a frontend to mencoder.
Comment: Seconded. What convinced you Handbrake uses mencoder in the first place? Also, what operating system are we talking about here?
Answer: Based on my experience with Handbrake on Windows and Linux: it does not use mencoder. Instead it offers its own command line interface: HandBrakeCLI.
On Windows one can click Show Queue>Queue>Generate Batch Script to export a script which contains all the command line parameters passed on to HandBrakeCLI. Although your reference to the "Activity Window" leads me to believe you're using Mac OS X, such an option may exist on the Mac version as well.
Comment: Appears to be outdated.  The only option within Show Queue for me is Start Queue in 1.0.7
Comment: Yup. Handbrake 1.0.7 doesn't even have the HandBrakeCLI anymore... :/
Answer: The reason I found this thread here is because, on
https://trac.handbrake.fr/wiki/CLIGuide
I noticed :
... under "Video Options"
-x, --encopts <string>  Specify advanced encoding options in the same
                        style as mencoder (all encoders except theora):
                        option1=value1:option2=value2

AND :
under "Picture Settings"
--crop: controls the cropping values. The cropping has to be in the form Top:Bottom:Left:Right, so to crop 60pixels from the top, 58 from the bottom, 2 from the left, and 6 from the right, use --crop 60:58:2:6

... do note that this is different from cropping in some other programs,
like MEncoder. If you don't enter this setting, HandBrake will
automatically detect how many pixels to crop to remove black borders.


Is "hot sun" grammatically correct?

Question: Can we use the term 'HOT SUN'. I am always confused if the term 'hot' can be used with sun. Eg: I don't want to go out in this hot sun.
Comment: Hi Ninni, welcome to ELU! I understand completely why you are asking this question. The answer is "Yes!" it's perfectly correct.
Comment: It's those cold January suns that put me off going outside. There's just *no* heat in them.
Answer: "I don't want to go out in this hot sun" is a perfectly acceptable and grammatical English sentence.  Hot is simply an adjective describing the effects of the sun.
Comment: However, if you're talking about the star then it could be a pleonasm, which is a form of tautology - i.e. a construct that repeats the same idea to put more stress on it (the spaceship plunged into the hot sun). That is, unless you are comparing it to other stars, in which case it could be relatively hot compared to all the others.
Answer: What makes the sentence correct is what the word "sun" really means.
The usual definition refers to the actual entity, the star in the middle of our solar system.
The definition of "sun" here does not refer to the star but rather the intensity of heat and light that the sun casts over the environment.
Therefore, it is perfectly logical to say "hot sun" due to the fact that you are commenting on the ambient heat rather than the actual star.
Answer: The answer is YES, it is the right choice. "I don't want to go out in this hot sun" is perfectly gramatical and current usage.
Hot - adj - capable of giving a sensation of heat or of burning.

In addition to "sun", "hot" (specifically meaning "having a high temperature") is often used with several other nouns:

hot dog
hot weather
hot bath
hot dinner
hot drink
hot oven

Hot (adj) can also be used in several contexts (formal, informal or slang) where it has completely different meanings. You'll find most of them at http://www.thefreedictionary.com/hot

Is "hot sun" grammatically correct?


How can I install Chromium browser on a bootable USB?

Question: I am having a hard time installing the Chromium Browser. Do I have to have Ubuntu fully installed to the hard drive to be able to do this?  For the time being, I am booting from USB.
Comment: to get the most useful answer, it s best to include the steps you took to attempt the install and any errors that you got when you did.
Answer: Short answer: Yes you can install apps to the bootable usb.
Long answer: Installing applications require enough space for the programs to run, so if you have Ubuntu on a small bootable usb then it may not have enough space to install. Also any apps that you install to the bootable drive will be deleted as soon as you shutdown or reboot the computer. You may also need to download new updates even with a fresh install of ubuntu with "sudo apt-get upgrade"
The bootable live or "try" ubuntu is NOT ment for daily use
Comment: Mostly true, if you have selected space for "persistence" (a small space is default when installing to USB, I believe) then any chnges you make will remain during reboots.  However, they will not remain during a full install- the installer will just install Ubuntu as normal and all changes will only remain on the USB.
Comment: also the amount of space on the USB is not relevant for the program to *run* the entire Ubuntu OS will be running in the RAM and the USB acts like a HD.  You will of course need enough space to *install* the program.  The USB is meant mostly to *try* but it can be used for repair of another computer or to keep a bootable OS on you that you can boot on any computer(say while travelling).  You will, of course not get the performance  of a full install but functionally it will be nearly the same.  I have used a bootable USB to get the viruses form a Windows system that would not boot.


Add an image to one feature within ArcGIS Online

Question: Using the web map pop up config, is there a way to add an image for one asset (polygon)? It appears the only option is to add an image for all the assets in that layer.
Comment: Enable attahcments on the featureclass before publishing. It will show a add attachment option the popup after publishing.
Answer: Let me know if this solution works: http://arcg.is/1KavGb
I threw it together fairly quickly but the "configure pop-up" feature allows for quite a bit more customization.
My process was this:

Create a shapefile in ArcGIS (I use Pro but any desktop version will work).
Include a text field for the link to a photo hosted on the web.  In this case it is on Wikimedia Commons.
Be sure to project the shapefile you create.
Upload the zipped shapefile and open it in a map.
Configure the pop-up in AGOL by choosing "A custom attribute display" and under "Pop-up media" add the field name where you placed the url in step 1.  (In my case I used {photo}.)

Using this process you could add a photo to any of the features.  If it is just one feature then that is the only one that does not have a null value for the photo attribute.
Good luck.
Comment: Thanks, I found a workaround by first creating a field to contain the link then adding the attachment directly to AGOL and sharing it to generate a URL. Now, the popup doesn't need to be modified and users can click the link next to appropriate field.


Android: Kernel Debugging with KGDB

Question: I'm trying to do kernel debugging for my Nexus One, and have been following instructions from http://bootloader.wikidot.com/android:kgdb. I was wondering if someone has actually got this to work? And has anyone done a more up to date solution for using KGDB to debug the kernel?
Comment: While having tools is nice and it would be great if you get this working, you might have faster luck solving a given gating problem and resuming with your project by careful use of printk's
Comment: Related question: [Android Kernel Debugging](http://stackoverflow.com/q/6697754/816008)
Answer: I found this post when I was looking for information of KGDB on Android so, despite it being a few years old, I thought it worth posting a link to some work I did to get this up and running on the Nexus 6.
http://www.contextis.com/resources/blog/kgdb-android-debugging-kernel-boss/
I hope this helps anyone else looking for similar answers.
Edited following feedback (thanks all):
To get this working I had to make a UART debug cable based on this Accuvant blog. This is quite a simple circuit which consists of a FTDI 3.3v basic breakout (available from SparkFun at the time of writing), as well as 4 resistors (2 x 1K Ohm, 1 x 1.2K Ohm and 1 x 100Ohm), and a 4-element Tip-Ring-Ring-Sleeve (TRRS) headphone jack. The resistors are essentially providing a voltage divider to reduce the 3.3v down to something a little safer for your phone. By inserting the audio jack with the other end connected to your circuit board, the audio subsystem recognises that a voltage (~2.8V) on the one of the pins and it knows to provide a UART interface via that cable. The FTDI breakout plugs into your PC via USB and from here you can access console messages via a terminal emulator like minicom. However, you now have a serial interface through the same mechanism and that's what we can use for a KGDB connection.
So at this point some relatively minor changes are required to the Nexus 6's serial driver (msm_serial_hs_lite.c) to support KGDB (specifically, the ability to perform atomic character I/O operations). I just ported these changes from the Linux Kernel mainline code as a chap called Stephen Boyd had done the hard work to the full MSM (Qualcomm) serial driver msm_serial.c. His changes can be found here or just search for "msm_serial: add support for poll_" on Google. The port wasn't difficult and my code can be found on github.
Aside from that you need to be able to build a custom kernel for your N6 which google provides lots of information on. You then need to create a boot image which contains the KGDB modifications in the github repo. I took the stock kernel from https://developers.google.com/android/nexus/images, extracted it (using abootimg -x) and then used the following command to repack it with my custom kernel (zImage-dtb) and additional command line params to ensure KGDB would be loaded and point to my serial port like so:
abootimg -u boot.img -k zImage-dtb -c 'cmdline=console=ttyHSL0,115200,n8 kgdboc=ttyHSL0,115200 kgdbretry=4'

With my boot.img created I could boot into it using the command fastboot boot boot.img, open an adb shell and then trigger a breakpoint in the Android kernel using the command:
echo -n g > /proc/sysrq-trigger

It is worth mentioning for completeness that you need superuser privileges to access /proc/sysrq-trigger so you need to have root.
With the phone halted, and your debug cable connected, launch a version of GDB for ARM on your host PC with your uncompressed kernel as an argument (e.g. arm-eabi-gdb ./vmlinux). Note: I'm running Ubuntu 14.04 and using arm-eabi-gdb from the 'prebuilts' directory in my AOSP source repository. Finally, enter the following commands:
set remoteflow off
set remotebaud 115200
target remote /dev/ttyUSB0

All being well this should immediately break into the kgdb breakpoint (that your write to /proc/sysrq-trigger produced) and you can start debugging.
Comment: This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post - you can always comment on your own posts, and once you have sufficient [reputation](http://stackoverflow.com/help/whats-reputation) you will be able to [comment on any post](http://stackoverflow.com/help/privileges/comment).
Comment: Hi Sufian. Thanks for your feedback. The OP asked two questions: 'has anyone got this working?' and 'does anyone have a more up to date solution for using KGDB to debug the kernel?' I couldn't get this working over USB (as referenced in the OP's link), but I got it working using a debug cable on a current Android device so I thought that satisfied the second question. Interested to know if you disagree?
Comment: That's a fair point. I've edited the post to provide more information. This is my first proper post so apologies for the lack of info (I actually responded to a similar question today and have fixed both now).
Comment: Is the down vote still applicable now that the info is contained within the answer and the second question was answered?
Answer: I know that you've already asked a question at the Android Kernel Dev list and got no answers, but did you search through the archives for posts about kgdb and debugging?: http://groups.google.com/group/android-kernel/search?group=android-kernel&q=kgdb&qt_g=Search+this+group
In particular, you might want to look at this post: http://groups.google.com/group/android-kernel/browse_thread/thread/5233e03391867c98/320beef11e737a62
Here's a few other random links that might be helpful:

http://www.cs.gmu.edu/~astavrou/courses/ISA_673/Android_Debugging/Android_GDB.pdf
http://www.cs.columbia.edu/~nieh/teaching/w4118/ubb/Forum6/HTML/000122.html
http://wiki.ncl.cs.columbia.edu/wiki/AndroidVirt:Guides:Kernel_Debugging
http://source.android.com/porting/debugging_gdb.html

Anyhow, this is an interesting question, and I'm really having a hard time finding anything on it. You might want want to try hopping on IRC sometime (#android-dev or #android-root on freenode) and asking some people there for pointers (please post up what you find here), or maybe asking on the xda-developers Android forums.

Android: Kernel Debugging with KGDB


Required documents for minor U.S. citizen entering and returning from Canada

Question: My 17-year-old daughter's passport expired on April 1, 2015. She is a U.S. citizen. I need to know if she will be allowed to across the border from Rochester, New York to Canada and back from Canada to Detroit. She has with her the expired passport and her original birth certificate, and will be traveling with her mother.
Answer:
Entering Canada by land: A birth certificate and photo identification should be enough to enter Canada.
Returning to the U.S. by land: A birth certificate is enough for children under 16. But your daughter is 17. Children 16-18 can also cross with just a birth certificate if they are in some kind of a group; that probably doesn't help.
An "enhanced driver's license" is also acceptable; only a few states have them, but New York and Michigan are included, if she is resident of either.
Finally, as a U.S. citizen, she cannot be denied entry to the U.S. as long as she can satisfactorily prove that she is a U.S. citizen, though they may give her a hard time. To that end, an expired passport (especially one recently expired) will work well. A U.S. birth certificate with photo ID will also work.
Comment: @Hoppe: I have updated the link
Comment: Is this statement still valid for July 2017: "Returning to the U.S. by land: A birth certificate is enough for children under 16"? I couldn't find the info on the link


Invite 5 friends to app and more

Question: I am trying to build a new Facebook application that will work only after the user will invite 5 of his friends and more.
So I found the possibility of using general engine inviting friends:

    <title> try </title>

     click here

Is there a way to add an option that must enter at least five members, and then transferred to new page? I'm still relatively new to PHP I'd love your help.
Answer: If you are after sending a apprequest to selected friends you can keep the selected friends Id in session and read it from your FacebookInviteFriends method.
function FacebookInviteFriends()
        {
            FB.ui({ method: 'apprequests',
            message: 'My diaolog...'});
            to: '<ids from session>'
        }
Answer: I think this question is not related to facebook or it's php sdk, but anyway, you can do it in so many ways I think. I do something like that in one app I just released:
1) In the FB.ui method, add the max_recipients option, like this:
FB.ui({
method: 'apprequests',
message: 'My diaolog...',
max_recipients: 1
});
2) Remember that the ui method allows you to attach a callback to it, so you can do something like this:
FB.ui({
method: 'apprequests',
message: 'My diaolog...',
max_recipients: 1
},function(response){
console.log(response)
});
In this response variable you have the ID of the user selected.
What I do next is to populate a form using this response. I have a form with hidden fields like this:
<form id="miform">
<input type="hidden" name="friend1" value="" id="f1">
<input type="hidden" name="friend2" value="" id="f2">
<input type="hidden" name="friend3" value="" id="f3">
<input type="hidden" name="friend4" value="" id="f4">
<input type="hidden" name="friend5" value="" id="f5">
</form>

With jquery, I populate the hidden inputs (remember, we're still inside the callback function):
$('#f1').attr('value',response.to[0]);

3) The last step is the validation, you can do it with javascript or php:
$('#myform').on('submit',function(){
// check if the fields are not empty and submit the form or alert if the fields are empty.
});

Hope this gives you a more clear view of what you have to do.
Regards.

Invite 5 friends to app and more


Complete IPv4 Address Space

Question: I know this was asked before, but I didn't get a definitive answer. I am trying to download a simple 17GB .txt file that contains the entire IPv4 address space. There must be a file like this already on the web.
Answer: You can simply generate them yourself. They are simply representations of all integers up to $2^{32}$
Which format do you want the address? There are many ways to represent them according to your requirements, due to the fact that they are simply representation of a set of normal numbers:

standard dot-separated e.g. 192.168.0.1
unsigned int32 : e.g 3548551264
hex, dotted hex, octal bytes

You could generate them in Python like this:
def generate_ips():
    """Generate all possible IPv4 addresses, on by one"""
    for i in range(255):
        for j in range(255):
            for k in range(255):
                for l in range(255):
                    yield "{0}.{1}.{2}.{3}".format(i, j, k, l)

The you must loop on the generator function like this to actuall use the values:
for ip in generate_ips():
    print(ip)

# output
0.0.0.0
0.0.0.1
0.0.0.2
0.0.0.3
0.0.0.4
0.0.0.5
0.0.0.6
0.0.0.7

I used a generator (with the yield keyword instead of saving all values in a list) because it will just give you one at a time and not consume all those Gb of memory that you mentioned!
If you want to store all values in a list for some reason, you can alter the function to append each IP address to a list, then return that:
def generate_ips():
    """Return a list of all possible IPv4 addresses"""
    all_ips = []
    for i in range(255):
        for j in range(255):
            for k in range(255):
                for l in range(255):
                    ip = "{0}.{1}.{2}.{3}".format(i, j, k, l)
                    all_ips.append(ip)
    return all_ips

Comment: Could we move this to chat for you to show me out to store them all in a list?
Comment: Are these two separate python files?
Comment: @C.Rutscher - I have added a simple list version. You can put the functions in the same file (give them different function names after `def`) and just run whichever one you need.
Comment: How do I output it to a .txt file though?
Comment: @C.Rutscher - Have alook for a tutorial [(like this one)](https://cmdlinetips.com/2012/09/three-ways-to-write-text-to-a-file-in-python/) online somewhere. There are lots!

Complete IPv4 Address Space


Kinetic Theory Proof

Question: How would I prove that the number of collisions by gas molecules on a wall of unit area per unit time is $r = \frac 1 4 n \left< v \right>$ using the Maxwell-Boltzmann speed distribution function? $r$ is the rate of collisions, $n$ is the number of molecules per unit volume, and $\left< v \right>$ is the average speed of the molecules.
Comment: You don't need to actually know the distribution function for this, just that its isotropic. It might help if you add what $r$ is to your question (presumably rate of particle effusion through a hole in some container).
Comment: What quantity is represented by $r$? (To my knowledge, $r$ is not a common sign for a thermodynamic quantity.)
Comment: I think $r$ is the rate of collisions of the gas molecules.
Answer: So imagine the entire space $z > 0$ is filled with this gas and you are looking at collisions on the plane $z=0$ in some time $t$. Considering the infinite space gives us translational invariance, so look at a small circle of area $dA$ centered at $(x, y) = (0, 0)$. Use spherical coordinates with $\phi$ being a polar angle down from $x=0, y=0, z>0$ and $\theta$ being an azimuthal angle counterclockwise from $y=0, x > 0,$ both measured in radians.
Somewhere out in space we have a small volume $dV = r^2\sin\phi~dr~d\phi~d\theta$ and it has a number of particles $dn = \rho~dV.$ What fraction of those pass through your square $dA$?
Well there's two concerns. One is the amount of solid angle occupied by the area $dA$. The particles at $(x, y, z) = (1, 0, \epsilon)$ for small $\epsilon$ see this area nearly edge-on and have a lot more trouble getting into it than the particles at $(x, y, z) = (0, 0, 1)$, which see it perpendicular. This boils down to a factor of $\cos \phi$, if you work it out.
In addition there's the more obvious concern that even if it were parallel, the chance of the particle having the right direction goes like $dA / 4\pi r^2.$
Finally it needs to have a velocity sufficient to traverse the distance in the given time. The easiest way to do this is with a cumulative distribution function: $F(s)$ is the probability that the speed $S$ is less than or equal to some value $s$, with $F(0) = 0$ and $F(\infty) \to 1.$ So you've got an expression for the rate $\eta$ of collisions, $$\frac{\eta}{dA} = \int_0^\infty dr~\int_0^{\pi/2}r~d\phi~\int_0^{2\pi}r~\sin\phi~d\theta~~\frac{\cos\phi}{4\pi r^2}~[1 -F(r/t)].$$You can immediately complete the angular integrals:$$\frac{\eta}{dA} = \frac{1}{2}~2\pi~\frac{1}{4\pi}~\int_0^\infty dr ~[1 - F(r/t)].$$So there's your mysterious $1/4$. As for the rest, you may first substitute $s = r/t, dr = t~ds  $  to find $$\frac{\eta}{t~dA} = \frac14 \int_0^\infty ds~[1 - F(s)],$$ then integrate by parts, raising $ds \to s$ and lowering $[1 - F(s)] \to -f(s)~ds$ to find an expression $\int s~f(s)~ds = \langle S \rangle,$ and you just check that the boundary terms are both zero.

Kinetic Theory Proof


control multiple inputs with one potentiometer

Question: I'm trying to build an analog synth. I'm reasonably adept in electronics but I have a problem. Its going to be a polyphonic so I want to have one pot controlling 4 oscillators because quad ones are expensive and I'm sure there must be a better way to do it. Is there a chip that could be used or is there something else I'm missing???
Comment: "cos" = "because" in UK casual use.
Comment: Please post a schematic of the design, it's impossible to say otherwise.
Comment: If they are VCOs then there shouldn't be a problem, just feed the same voltage to each.
Answer: Building a polysynth is quite a bit different chore from building a monosynth. Don't expect you can simply just take a mono synth voice, replicate that n times, and somehow magically wire them up as a polysynth.
The trick is that the voice has to be entirely voltage controlled, including all the static parameters that in a mono synth would be controlled by a simple potentiometer or a switch (switches would usually be replaced by a 4053 analog switch or a more modern equivalent). Then you use a microcontroller to generate control voltages and switch signals for the voices, and to read the keyboard, MIDI, digitize the front panel potentiometers and so on. As a free side-effect it's now quite trivial to implement patch storage on the micro.
If you do that naively, for \$k\$ analog parameters and \$n\$ voices you need \$kn\$ DAC channels, plus a bunch of digital outputs for the switches. As even a simple synth voice can easily have 20 parameters, for 8 voices you'd need 160 DAC channels! So the first thing you do is that you of course use just one channel to feed all of the parameters that are identical between voices (typically everything else except pitch control and envelope gates). This is why analog polys are typically not fully multitimbral. The second thing is that you use an analog multiplexer and sample-and-hold (such as a 4052, a hold cap and an opamp buffer) to generate the control voltages (if you're hand building a one-off instead of a commercial product, you might want to just splash out for a lot of multichannel SPI DAC's though, just to save up on soldering at the expense of a lot higher component cost).
By the way, you can probably see at this stage that writing the software for the microcontroller is not a completely trivial task...
In the modern day and age, your biggest challenge in the analog sense is to have an ADSR where the A, D, S, and R are all voltage controlled, without using a huge number of components per voice. Most modern polys solve this by having digital envelopes (but then this means that there's a DAC channel per voice for each of the envelopes, since their output will typically be different), whereas older polys typically had an ADSR IC. As it happens, such an IC is again in production, though it's not cheap: AS3310.
The details on how to do the multiplexing, converting typical monosynth circuits to complete voltage control and so on, are way too long for a EE.SE answer. However, you can get the idea, and a lot of inspiration, by studying the service manuals of the old classics, containing full schematics, many of which are readily found on google. Out of the really big names, at least the OB-Xa and Jupiter 8 schematics are immediately available. Note though that much of the details of the computer control can be done much easier today, since back then microcontrollers with integrated everything didn't yet really exist, so don't try to slavishly copy everything in these manuals.
So, to sum up: if you want to build a poly, you're signing up for quite a lot more than just replicating monosynth voices. However, it is a rewarding task, and if you want to pursue it I wish you the best of luck (and I, for one, would be interested in reading about your progress on a blog or such, if you're so inclined)!
Comment: @FinSmy Thanks! If you think my answer was helpful, maybe you could accept it as the correct answer? :)
Answer: The differences between a Quad pot and a single I can think of are two fold:

In a quad pot the load is only 1/4 of the single pot. This can be compensated by using a single pot of four times lower value.
If the destination is somehow injecting noise on the signal, on a quad pot this will hardly effect the other channels. In a single pot it will feed to the other channels. In that case you could use a a quad set of Op-Amps in 1x amplify mode. That will also remove the load from the pot but may introduce a bit of noise.
Comment: I'm curious about the type of pot you are describing. Can you post a link to a picture or datasheet for your 'quad pot'? OP, I think, was describing a 4-gang potentiometer.
Comment: @Transistor I was talking about a 4-gang potentiometer but using the OP's nomenclature. What I understood he wanted to replicate a one-pot voltage divider, four times but on one axle, thus providing the same voltage four times to four different end-points.


Scraping sound from front right wheel area

Question: Was driving earlier when noticed what sounds like scraping from drivers side front wheel. Doesn't make a sound while driving at normal speed. Only while driving slow or slowing down I've had in up on the jack and not making a sound unless I spin wheel one direction then quickly change direction but even then only a small knock then nothing. Have no idea what's causing the sound but sounds like something is scraping alone the ground (there isn't)
It's a seat Leon 58 plate.
Answer: You may not hear it at normal speed because perhaps the sound changes its pitch to some higher frequency, but that sound can be "mainly" two things:
a) brake pads wasted to their steel supports
b) bearings going out of lub
Check as this:
a) Jack the car, try to move the wheel first pulling in/out horizontally (one hand at 10:00 other hand at 3:00, and pull in/out one hand first then the other). If you feel it "loose", hear noises, clicks, etc you may have tie rods problems...great to find but that's not your issue :) Now do the same but vertically (one 12:00, the other 6:00, pull in/out...loose, noise, clicks means bearing problems)...that's what you need to address.
b) Jack the car, rotate the wheel to driving direction and with the help of someone "slightly" very slightly press brake pedal. The idea is not to stop the wheel but let the pads rub the disk then rear the noise. If something resembles what you heard, then the pads are done.
c) Jack the car, remove the wheel, visually inspect the brake pads. If needed, put the wheel fasteners to secure the brake disk and rotate it. With the help of a screwdriver pinch the pads. Also check if the dust cover inwards the brake system touches the disk, maybe it is bent or loose.
e) Silly but also makes those sounds: put the car on ground, check if there is any plastic cover, rubber, hose, etc rubbing the wheel!
Bearing problems are commonly a grinding non-intermittent sound. By scrapping sound I infer it is an intermittent sound, so maybe not the bearing...but good to check as in a) anyway.
Answer: Check for an object between the breaking disc and the well behind it
There are instances of rocks getting stuck behind them and you might hear them at certain lower speeds. At higher speeds the frequency of the sound changes and other road and wind noises overlay the sound of the friction.
Jack the car, get the wheel off, then look between the disc and the well. See if there is an object between the two, usually a small rock. If so, use e.g. a screwdriver to remove the rock, make sure the disc and the well are still aligned properly and then put the wheel back on.
This is of course but an option. The suggestions by @AramAlvarez are just as valid.


Where can I find more information of Gov2 specifications/documentation?

Question: Other than the information presented (shown below), is there a way to keep track of the Gov2 technical specifications?

https://polkadot.network/blog/gov2-polkadots-next-generation-of-decentralised-governance/
https://www.youtube.com/watch?v=EF93ZM_P_Oc
Answer: Specifically about the Polkadot Fellowship, which makes up a large part of it, you can take a look at the manifesto: https://github.com/polkadot-fellows/manifesto/blob/main/manifesto.pdf
Answer: I suggest you take a look at this PR adding Gov v2 on Kusama. It might also be worthwhile checking out the ranked_collective pallet, which seems crucial for the new governance model.
Answer: Perhaps overly complex, but until a nicely formatted page is available you can see this file here for the current parameters Kusama has been configured with:
https://github.com/paritytech/polkadot/blob/master/runtime/kusama/src/governance/tracks.rs
e.g. for a small tip:
<code>pallet_referenda::TrackInfo {
        name: "small_tipper",
        max_deciding: 200,
        decision_deposit: 5 * QUID,
        prepare_period: 4,
        decision_period: 28 * DAYS,
        confirm_period: 3 * HOURS,
        min_enactment_period: 28 * DAYS,
        min_approval: APP_SMALL_TIPPER,
        min_support: SUP_SMALL_TIPPER,
}
</code>


Salt = Sodium Chloride, for this question

Question: I think it should be clarified in this question that the salt generally being referred to is sodium chloride. However, the human body requirements for salt may be more than just sodium chloride, so it may affect the context of some of the answers (eg one commenter says they eat salt to avoid cramp. I've heard of magnesium salts being used for this instead!). Any suggestions (or volunteers!) on how to tidy this up?
Answer: If you're talking to the general public, salt means sodium chloride. Everyone understands what is meant by it and there is no need to use the exact chemical term in this case, I think.


Working abroad, get paid in USD or GBP?

Question: I am going to work abroad and be paid by a US organization. They are paying into my UK bank account which charges £6 for receiving a foreign payment. I have the option of being paid in USD or another currency. Their exchange rate should be fair as it's not a commercial company. Should I ask to be paid in GBP, or USD and risk whatever exchange rate my bank has at the time of being paid?
Comment: Get a better bank account? You ought to be able to beat the GBP 6 fee for receiving an incoming international wire transfer
Answer: There are probably no less than a dozen different banks that will allow you to open an account today and be happy that you are making regular deposits into that account, all without ever charging you a penny. If your bank is charging for that, they are either crazy, or ripping you off.
Now as to your question, I've found it to generally be cheaper to have transfers be in the currency of the bank receiving the money. So if your primary account is based in the UK, you're probably best off getting paid in GBP.
Comment: My experience with US banks in particular, however, is that their foreign exchange rates tend to be awful and it almost always works out better to transfer US dollars in and out of the US bank and do the exchange at the overseas bank. A US$-denominated account in the non-US bank to accept the transfer gives one some control over the currency conversion (my Canadian bank gives me a better rate if I accumulate US dollars and convert them in a bigger chunk).
Comment: Isn't the singular "penny"?
Answer: If you are living in US and do not have any payments in UK I think is more reliable for you to get paid in US dollars in a US bank account.
If you see how sterling pound is going down, maybe you can make more cash in the future moving your savings to UK in a cheaper currency using low charges websites like Transferwise.
I did few times from £ to € and viceversa.

Working abroad, get paid in USD or GBP?


Disable remote file cleanup in recentf?

Question: When using recentf with tramp, recentf would clean up its file list including all remote files, which takes a lot of time when the Internet is bad. How can I ask recentf to not cleanup remote files, without disabling recent file list auto cleanup for local files?
Answer: M-x customize-option RET recentf-keep RET, and be sure to read its description.
You can use any arbitrary or conditional expression. And that includes file-remote-p.
Comment: @joefromct: Yes; updated. Thx.
Comment: sort of old, but maybe you mean't `file-remote-p` ?
Comment: I am facing the exact same issue: remote files are removed from the recentf list of my local emacs after a shut-down of the remote server. I would like for them to keep around. What exactly do I have to specify here and where do I have to do that?

Disable remote file cleanup in recentf?


Who is devi Jyoti/jwalamukhi?

Question: According to this YouTube Video, There are 8 children of Shiva. While 7 are known ones, but the last one is devi Jyoti, also known as Jwalamukhi and Rayaki. Can somebody share scriptural reference of her being daughter of Shiva and Parvati and how was she manifested?
Comment: @Vivikta She is also known as Jwalamukhi Devi. I'll better put this in question body.
Comment: Though, i dont remember the exact source but Its no folk tale or anything, like atall. Period. She is the goddess of light (jyoti) and "Vel" (spear) of Lord Kartikeya. Also the destructive fire present in the hand of Lord Shiva's Nataraja Swaroopa so called as Goddess Jwalamukhi. She is also mentioned in tantras as the Kundali Shakti. There are many verses in vedas and Upanishads that are dedicated to devi jyoti (spiritual light).
Comment: Sounds like a folk tale.
Comment: I already read and knew about the Jvalamukhi in the Shiva Purana. Although, that, as per your own question, cannot be the answer, since she's said to be the daughter of Shiva & Parvati. In the answer below, she emanated from Sati only.
Answer: In Shiva Purana, Jwalamukhi Devi is mentioned to be born/created out of the fire in Goddess Sati's body. This was during the event of destruction of Daksha Yajna.

Even as the whole of the world of Devas was witnessing, the process of destruction of the sacrifice was carried out by Vīrabhadra
and others, the followers of Rudra.

The policy in agreement with what is laid down in the Vedas and Smṛtis is this, O Sage, which you must note. When lord Rudra is angry,
how can there be happiness in the world?

On hearing his song of praise Rudra relented. Favourably disposed to the miserable that he was, he granted their request.

Śiva, the great lord, indulging in different sorts of divine sports, became sympathetic and merciful as before.

Dakṣa was resuscitated. The whole sacrifice was renewed under the instruction of the merciful Lord Śiva. All those present were honoured
in due manner.

O sage, in that sacrifice Rudra was honoured by all the Gods with due devotion. They were highly delighted.

41. The flame of fire arising from the body of Satī and delighting the whole world fell on that mountain and it was duly worshipped.
42. The deity became famous as Jvālāmukhī yielding fruits of cherished desires. Even her very vision quells all sins.

Since the Devi was born out of Goddess Sati, she can be considered as a 'child" of Sati and hence that of Lord Shiva too.
She has been mentioned in Skanda Purana too.
Quoting from the "Essence of the Skanda Purana":

'Tripuranthak Kshetra' where the Three Eyed Siva demolishes the
devotees' fear of 'Naraka'; 'Prabhasa Kshetra'where Sri Krishna and
Balabhadra worship 'Chandrardha Sekhar'; 'Jaalandhar kshetra'where
Andhakasura was killed by Siva and Jalandhar did Tapasya to become the
Head of 'Shivaganas'; 'Jwalamukhi' Sthaan ( Place) where Devi
Jwalamukhi worships 'Kaala Rudra'; 'Triambakeswar' on the banks of
Godavari River where Kartikeya secured the Shakti to kill Tarakasura
and so on.

Quite possible that more details about her are mentioned in various other Puranas too.
Comment: They are same only, just the origin differs, even the origins of Lord Skanda also deffers in Mahabharata itself, maybe due to kalpa bheda. Though, as i have mentioned in above comment, i don't remember the exact source where i have read about Goddess Jyoti Devi. ..
Comment: Thanks savdy .... @Savdy
Comment: @Rickross u r welcome. I also read that she is the shakti of the "Vel" of Lord Murugan, that's why his spear is not that of a typical triangular shape but in the shape of a "jyoti" (tear shaped). Anyways, buddy. Cya. Tc. ..
Comment: Check this wiki link: https://en.m.wikipedia.org/wiki/Jyoti_(goddess)
Comment: So Devi Jyothi and Devi Jwalamukhi both are not the same ?@TheLittleNaruto

Who is devi Jyoti/jwalamukhi?


Type name 'serializeObject' does not exist in the type 'JsonConvert'

Question: I am trying to convert some data to Json to send to the CloudFlare API. I am attempting to use Newtonsoft.Json.JsonConvert.SeriablizeObject() to accomplish this but I am getting the Intellisense error that the type name 'serializeObject' does not exist in the type 'JsonConvert'. I have the NuGet package Newtonsoft.Json installed but it does not recognize the SerializeObject() method. I am not sure what I am missing.
Comment: clean, remove bin and obj folder, rebuild before trying anything btw
Answer: Its because you're calling the method wrong, remove the new operator from the line
var json = new JsonConvert.SerializeObject(updateDnsRecord);

to
var json = JsonConvert.SerializeObject(updateDnsRecord);

Comment: Thanks that fixed it. I both love and hate when it is easy. I feel like an idiot but it doesn't take long
Comment: I will. It is telling me I have to wait 6 minutes
Comment: I get what you're saying, and it wont get better with experience its something that sticks though your whole career i feel like. But thats the bane and beaty of SE. Go ahead and mark this answer with completion if you could.
Comment: @reusablePants ah okay. Yeah there seems to be some wait time nowadays - i dont remember that being there anymore. Still feel like there are so many open questions on SO that could've been closed so im trying to do my part.


Are there studies of detriments to using deodorants?

Question: Specifically, I'm looking at Old Spice and Axe sprays. The labels warn that users should not inhale the fragrance (ironic given its purpose), but what are the consequences of prolonged inhalation?
Comment: that depends on the composition of those sprays.
Comment: I recommend carefully distinguishing between deodorants and antitranspirants when phrasing the question, as the two are often colloquially used as synonyms but in fact they are not, and there are significant differences in their potential side effects; but then again, this is relativized as you explicitly ask about consequences *on inhalation*, which then would exclude the others. So I'd generally recommend paraphrasing the question to be more specific.
Answer: I can't speak for Old Spice, but Lynx/Axe is basically just a solution of perfume in ethanol. The ethanol kills the skin bacteria that generate the malodour (though the population quickly recovers!) and the perfume just makes you smell nice.
Pure/concentrated ethanol will destroy cell membranes, which is how it kills skin bacteria, so it's more dangerous than its widespread use in drinks would suggest (though fortunately diluting ethanol with water greatly reduces the damage to cell membranes). The solvent in Axe is about 95% ethanol and this is concentrated enough to cause damage. There isn't very much ethanol in a typical few seconds of spray, but I suppose if you pointed the can up your nose and inhaled as you sprayed you might cause some real damage. I suspect the intense pain it causes would mean most people will do this only once!
But I would guess the most dangerous ingredient in the deodorant is the perfume. Perfumes are an unholy mixture of terpenes, alcohols, ketones and lots of other stuff, and many of these chemicals are irritating to skin. Handling flasks of pure perfume is done in a fume cupboard with gloves and protective eye wear. Getting any large amount of perfume onto a mucous membrane like the eyes, throat or lungs would cause irritation and pain. But again, the amount of perfume in a few seconds of spray is small and you'd have to work at it to do yourself any serious harm.
I suspect the warnings not to breathe the spray are largely just being cautious and/or a way of being protected from being sued. Though in principle the contents of the spray can cause harm this would take exceptional circumstances, and even then the result is likely to be local irritation rather than any serious damage.
Later:
To my considerable surprise I have found a safety data sheet for Axe deodorant online (note that this is a 55KB PDF). The sheet gives the formulation though it omits the perfume concentration. I would guess this is because the perfume concentration is below the level where it has to be disclosed. The section on toxicology states:
<code>SECTION XI. TOXICOLOGY INFORMATION
ACUTE EFFECTS
EYE CONTACT: May cause redness or irritation.
SKIN CONTACT: Overexposure may cause a skin reaction such as redness. Do not use on broken skin.
INGESTION: May cause nausea, vomiting and diarrhea.
RESPIRATORY: Intentional misuse by deliberately concentrating and inhaling the contents can be fatal or
harmful.
CHRONIC EFFECTS: None expected
CARCINOGEN CLASSIFICATIONS
NTP: None
IARC: None
OSHA: None
</code>
Comment: I suspect there is more to the warning of "don't inhale" than legal overcautiousness. If it is a spray, there are probably other unsavory things added to it to keep the pressure system working, just like cans of compressed "air" have gases added to it and should not be huffed.
Comment: @rumtscho: the propellants are normally low molecular weight alkanes, and these are entirely harmless.
Comment: @DaveL: I need to be a bit careful because I was at one time employed by the company that makes Axe. I'm no longer employed by them, but I feel uneasy talking about stuff that is potentially confidential - like the formulation of Axe. What sources would you like me to cite? Toxicity data on ethanol is just a Google away, though I suspect finding publically available deodorant formulations would be harder.
Comment: @DaveL: to my surprise i managed to find a safety data sheet for Axe online


What is the most efficient method to iterate geoprocessing operations through an attribute table?

Question: I want to calculate the clipped raster layer percentage for a shapefile consist of overlapping polygons, since ArcGIS doesn't support tabulate area for overlapping features, so I used a loop to process each of these overlapping feature one by one:
1: Create an independent shapefile for each polygon from the attribute table
2: Clip the raster layer using the single one polygon created from step 1.
3: Calculate the raster grid percentage by counting the numbers of raster grids in each categories.
I was able to code this up, and the script run well but slowly for a big dataset. I run this loop for 2000+ big overlapping polygons and it took hours. I tried to optimize this computation by:
1: Use arcpy.da.SearchCursor instead of arcpy.SearchCursor

2: Using in-memory workspace to storage the temperate files.

3: Use Parallel Processing: arcpy.env.parallelProcessingFactor = "100%"

These are all helpful but I still think can improve more. I am thinking about using python parallel processing tool such as map function. Could anyone suggest on how to apply the map function on this loop process?
The following is the skeleton of my script:
featureClass = "E:/ArcGIS/access_to_recreation/new.gdb/Portland_ME_service_2hr"
rows = arcpy.da.SearchCursor(featureClass, ['FacilityID'])

# Loop through attribute table

for row in rows:
    id = row[0]

 # Extract each row as a independent polygon layer throughout the entire table
    inputfc = "E:/ArcGIS/access_to_recreation/new.gdb/Portland_ME_service_2hr"
    outputfc = "in_memory\\feature"         # edit here!
    fieldname = "FacilityID"
    fieldvalue = id
    # construct the where clause by calling the helper function
    where_clause = buildWhereClause(inputfc, fieldname, fieldvalue)
    # execute Select analysis, create separate layers
    arcpy.Select_analysis(inputfc, outputfc, where_clause)

    # # Clip the raster data using each polygon
    inRaster = "E:/ArcGIS/PAD/For_Recreational.gdb/PAD_Parks_continental_final"
    inMaskData = "in_memory\\feature"  # edit here!

    # Execute ExtractByMask
    outExtractByMask = ExtractByMask(inRaster, inMaskData)
    outExtractByMask.save("in_memory\\extract_mask.img")

# build raster attribute table
    try:
        arcpy.BuildRasterAttributeTable_management("in_memory\\extract_mask.img", "Overwrite")

    # Count the 0, 1 pixels in the mask output
    raster_rows = arcpy.da.SearchCursor("in_memory\\extract_mask.img", ['OID', 'Value', 'Count'])

    try:
        for ra_row in raster_rows:
            if ra_row[0] == 0:
                blank = ra_row[2]
            else:
                value = ra_row[2]
        percentage = 100 * float(value)/(float(blank)+ float(value))
    except:
        percentage = 0

    Percentage.append(percentage)
    ID_list.append(id)

    # Delete intermediate files
    arcpy.Delete_management("in_memory")

Comment: Just off the top of my head, you may want to take out some of your variables in the `for` loop, and place them one line above it. Since they don't rely on the search cursor to be defined.
Answer: You should not need to write the temporary rasters on disks. arcpy optimization is quite obscure to me, but not writing the feature class should help. In fact, you should be able to use geometry object directly for the clip
for row in rows:

    # Execute ExtractByMask
    outExtractByMask = ExtractByMask(inRaster, row.getValue(shapefieldname))
    outExtractByMask.save("in_memory\\extract_mask.img")

Answer: If I understand your question correctly, the following workflow could be an alternative.
Create sets of non-overlapping polygon either by code (see this discussion) or manually (run 'zonal statistics as table', identify the zones that have not been calculated and separate them into a new layer. Repeat with the separated layer to find more potential overlapping zones until none exist.)
Then reclassify your parcs raster to a binary grid with zeros (what you refer to as 'blank') and everything else with ones (your field 'value').
Create a script and run the "zonal statistics as table" function with each of your polygon sets and concatenate the tables. The resulting tables will have the total number of cells within each zone and the sum of the values which will be the number of cells with parks. From there it should be easy to calculate percentage.
Zonal stats is lightning fast in current versions of ArcGIS.


"would love/like to" usage?

Question: What is the difference between the sentences
"I would love/like to play cricket" and " I want to play cricket." Is there any difference in the moods?
Comment: What does the dictionary tell you?
Comment: The three forms are not totally interchangeable. For instance, 'Smith Minor, you have a choice of activities for this afternoon. Look at the list: which do you prefer?' would not often be answered with the 'love' variant. 'My eyesight is so poor that I am restricted in what I can do.' would not normally be followed by 'I want to play cricket.' 'You're not going out until you've finished your homework.' virtually mandates '[But] I want to play cricket!'
Answer: Further to tchrist's answer, they're different, but it's more complicated than it looks.
I want to play cricket: whether the option to play cricket is available or not, to play cricket is what I want to be doing right now. I don't want to be sitting at my boring office job wasting time on ELU; I want to play cricket, dammit.
I would love to play cricket. I read this as one of: 1) My friend has asked me if I want to play cricket right now and I've replied "I would love to play cricket!" This could be followed by me saying either "So let's play!" or "But unfortunately I can't because I'm at my boring office job wasting time on ELU."
OR 2) If it were possible to play cricket right now, I would gladly do so, but alas it is not possible at all.
Answer: Yes, the moods are different:

want is in the indicative mood.
would love is (arguably) in the conditional mood, or perhaps the optative.
Comment: Two grammarians walk into a bar ... :)
Comment: @JohnLawler Is this restricted usage of 'tense' now universal (or at least preponderant) among students of linguistics? In my youth it was otherwise: "Tense is ... a deictic category ... a property of the sentence and the utterance" (Lyons, *Introduction to Theoretical Linguistics*, 305). If your usage is now standard, what term is now used for the category Lyons describes?
Comment: Alas, English doesn't have any verb moods. It has lots of verb constructions, however.
Comment: @JohnLawler You're right that English has no morphological inflections of the single-word verb that alter the mood of the verb. I don't think matters so much, though, because it has no shortage of standard multiword constructions that convey the corresponding senses which in other languages are carried by the inflexional morphology alone. French may use *-ai* for future and *-ais* for conditional where English might use (say) *will* vs *would* as separate words. Does that distinction really matter all that much, and if so, why?  And welcome back, John.
Comment: Thanks. The term _mood_ has a precise meaning, and it's a formal meaning. I.e, it refers to inflectional **forms** that have modal meanings of a certain sort (_mood, mode,_ and _modal_ are all the same term). But English has almost no inflections left, so it has no moods, no voices, and [only two tenses](http://www.umich.edu/~jlawler/aue/tense.html). If you want to give some construction a particular name, that's fine, except nobody ever gives it the same name, so it's not grammar, just branding.
Comment: I'm really not sure what Lyons had in mind; things that are properties of sentences and utterances are usually not grammar, but semantics or pragmatics. A standard definition of tense is provided by the SIL [here](http://www.sil.org/linguistics/GlossaryOfLinguisticTerms/WhatIsTense.htm).
Answer: The first phrase is expressing an affection for playing cricket. The other phrase is a basic agreement to play or a statement wishing to fulfill a need.
Context surrounding the phrase may affect how the phrase is received:

In the right conversation and sarcastic tone, "I love to play cricket" can mean just the opposite.
"Love to play cricket" can also imply an unnecessarily exaggerated form of  simple confirmation.
Answer:
would like/want are the same meaning, but would like is more formal: all of these are indicative mood
would love is conditional mood
Comment: How is *I would love* conditional when the identical structure *I would like* is indicative? This answer is wrong, I'm afraid.
Comment: yeah,, I agree with you

"would love/like to" usage?


How can I debug a web service called asynchronously from javascript?

Question: I have a ASP.NET web service that I used to asynchronously save data to my database. I have a button on my webpage that invokes a javascript method which looks through the dom, gathers the data and sends it off to the service.
I'm debugging a problem right now that I believe is happening in this web service, and I would like to debug the web service when it gets invoked, but I'm not sure if this can be done, and if so how?
Something very strange is going on in that service, so I'd like to be able to step through it and figure out where the problem is occurring.
Answer: You will need to attach the debugger to the process hosting the web service. This would be aspnet_wp in IIS 5, w3wp in IIS 6 or 7, or could be the Visual Studio Development Server if it's running in the same solution.
Once the debugger is attached, simply open the source of the service and set breakpoints. If you're attached to the correct process, then the breakpoints will appear as filled-in circles; if not, they'll be hollow circles with a warning icon. Hover over the icon to see what the problem is.
Answer: Have you tried placing a breakpoint in the codebehind in the web service?  It works fine for me... but maybe I'm missing something.
Comment: I tried placing a breakpoint and it didn't catch it for some reason.
Answer: Firebug was made for exactly this task http://getfirebug.com/ on the client side.
On the server side, use standard tools (debuggers, loggers ...)