Do airlines check the content of checked luggage?

Question: I read Lufthansa "bans AirTags in luggage" after passengers publicly shame it with location of lost bags. Do airlines check the content of checked luggage? I thought only the TSA and their non-US counterparts screened luggage, not the airlines.
Comment: I don't see where that article states that the airline can or does check your luggage.  When you check-in you are asked whether your luggage contains any of a range of dangerous or banned items.  This would be when they check.  I would assume that they have added Air Tags to this list of items.
Comment: @Midavalo hence my question.
Answer:
That's fake news. It originated with a reply tweet, quickly deleted. It was a mistake. If boingboing bothered to ask Lufthansa they would have gotten this reply: https://twitter.com/ethanklapper/status/1578453321546801158

A Lufthansa spokesperson tells me there is no change to the carrier's policy on AirTags.

Instead, they printed this garbage.

Airlines do not check luggage. That's the job of the same security force who mans the security checkpoints. For example, read Toronto Pearson, the TSA about this.
Comment: The "no change in policy" does not actually say they allow them. They can easily point you to their policies stating, based on ICAO rules, that devices containing Lithium-based batteries in checked luggage must be completely turned off. So no, they didn't ban AirTags, they never allowed **active** AirTags in checked luggage anyway. Since there's probably no way to actually turn off an AirTag… on the other hand, airlines indeed usually don't check luggage, but security checks could reveal the presence of a Lithium-based battery and trigger a check (by security, not the airline).
Comment: I believe there's a similar ongoing debate on "smart" luggage (with built-in trackers and/or built-in electronic tags), not sure what the situation is on that at this time.
Comment: Airtags also violate further restrictions, which have been in place for a long time. Not only is the battery in combination with 'can't be turned off' a violation of ICAO rules, but they are also banned (both in checked and carry-on luggage) for containing a radio transmitter, which can't be turned off. Lufthansa also has their own luggage restrictions going beyond the ICAO requirements and do not allow devices containing lithium batteries at all in checked luggage, even if they are turned off.


STLink 3.3V target power

Question: In order to program a target MCU with STLink you need to connect 4 wires - SWCLK, SWDIO, GND and VCC (3.3V). STLink v2 programmer has 3.3V pin already present and ready to use. But let's say I would like to use my STM32F401 Nucleo-64 development board as a programmer. In this case, I need to remove CN2 jumpers and use SWD connector. The problem is, SWD connector does not have target power (3.3V) pin. Where do I get 3.3V? Can I just take it from nucleo board?
Comment: you can take power from the nucleo board yes, within limits of course.
Answer: Even an ST Link does not provide target power. You connect Vcc to power the level shifter in the ST Link.
Such that the ST Link does not blow up an 1.8V target.
The budget version of the ST Link on the development boards do not offer this, and are only capable of interfacing with 3.3V targets. If your target is 3.3V, and not powered from elsewhere, you can connect 3.3V. If it is self-powered you can omit 3.3V.
I cannot find a board photo or circuit of the ST Link V2, but it will have some logic IC that provides level shifting/buffering between the STM32F103 (used in ST Link) and the target connector.
From the user manual of ST Link V2:

JTAG/serial wire debugging (SWD) specific features
  – 1.65 V to 3.6 V application voltage supported on the JTAG/SWD interface and 5 V
  tolerant inputs

And the remark at the pinout table:

The power supply from the application board is connected to the ST-LINK/V2 debugging and programming
  board to ensure signal compatibility between both boards.
Comment: I am talking about ST Link interface like this: https://www.electrodragon.com/wp-content/uploads/2013/09/ST-Link-V2-Programmer-For-STM8-STM32.jpg
Comment: @jurij that's a budget version. Do not assume any level shifting is available. Skip the 3.3V wire.
Answer: On this figure: https://electronics.stackexchange.com/a/330710/33532
The yellow wire coming from the jp1 connector next to the USB on the STLinkV2 of the Nucleo-64 development board is carrying the 3.3v from the STLinkV2 to the target

STLink 3.3V target power


Where would I ask a question about what significance some words have in a song?

Question: Where would I ask a question about what significance certain words have in a old Spiritual song?
Answer: If the question you have in mind is an interpretation-like question, then Literature Stack Exchange would be a good fit. (This site did not yet exist when the previous answers were posted.)
This type of question would be tagged with meaning and song-lyrics. At this moment, the site has 35 questions about meaning in song lyrics.
Answer: There is no site for this type of question at the moment, but there will be one very soon. The Music Fans site is about to be launched into private beta.
As you can see from this question, questions about the meaning of words in a song will be acceptable for the Music Fans site.
Comment: *Probably* will be allowed. As any new community, they may change scope and focus over time. Proposed questions on Area 51 aren't necessarily a guarantee of anything.
Comment: And just 14 hours later, Music Fans is in private beta.
Answer: If you know the language of the words and make it sufficiently narrow, such a question may be on-topic on the SE for the corresponding language, if one exists. If you do not know it, language-identification seems to be on-topic on Linguistics.
If your question is rather about the spiritual interpretation of the song, it may be on-topic on the SE for the respective religion, if one exists.
What of the above suggestions actually fits, if any, strongly depends on your actual question. So be careful to get an idea of the respective Stack Exchanges before asking, lest your question be closed.


DNA sequence and algebra

Question: DNA is made of a string of different proteins.There are 4 different proteins which make up the human DNA.We can represent each protein as a 2 bit sequence of '0' and '1'.However wouldnt it be much better if we had 4 available logic states('0','1','2','3') for every type of protein?How would a algebra having as a base 4 available logic states look like compared to boolean algebra?
Comment: Thank you for posting this question. Unfortunately, your question is unclear, and it is very unlikely anyone could answer it without further details. In particular, it is not clear what you mean by an "algebra" with "available states". We will put the question on-hold for the time being, but you will still be able to edit and improve it. Once you clarify the question you can flag it to get our attention. See our [FAQ#close] for further details!
Comment: Edited.I hope it is more clear now.
Comment: What is the purpose of this algebra?
Comment: To describe a sequence of DNA proteins or what is the complementary of each protein.
Answer: DNA is a long-chain polymer. The monomers that comprise a DNA strand are referred to as "nucleotides".
A protein is a completely different polymer, the monomers of which are called amino acids. The "standard model" relationship between the two (which is a little more complex in practice) is that the "coding regions" of DNA encode sequences of amino acids, DNA is transcribed into RNA, and these RNA transcriptions get turned into proteins.
A nucleotide is comprised of a sugar molecule onto which there are two additional radicals: phosphate, which links the sugar molecules together into a chain, and one of four bases: adenosine, cytosine, guanine, and thymine (hereafter referred to A, C, G, and T).
In bioinformatics, we don't typically care about the difference between a "nucleotide" and a "base" and tend to use the terms interchangeably.
DNA is organised into a double helix structure. We can read each helix strand in a known order, typically 5' to 3'. The sugar molecule has a pentagonal structure, and the primes refer to where on that pentagon the phosphate molecules bond.
The other strand of the helix is (assuming no errors) the "reverse complement". The strand has the opposite order (using 5'-3' ordering), and each nucleotide is hydrogen-bonded with its complement: A is the complement of T, and C is the complement of G.
So, for example, to find the reverse complement of the sequence ATTTG, swap each nucleotide for its complement, and reverse the whole sequence, obtaining CAAAT.
A quirk of the Latin alphabet is that if you represent the four nucleotides in alphabetical order and assign a two-bit code to them, the complement of a nucleotide is its the logical "not".
00 A Adenosine
01 C Cytosine
10 G Guanine
11 T Thymine

The complement of a nucleotide isn't that useful on its own. The reason why it's important is that if you read a sequence of DNA, you could be reading from either strand of the double helix. You therefore need to consider the reverse complement of a sequence, not merely the complement of each base.
There are lots of situations where interpreting nucleotides as algebraic objects are useful, but which interpretation you pick depends on precisely what you're trying to do.
As a real example, I was once tasked with designing an error-correcting code for tagging DNA samples. The first approach I tried was to use a linear code, and that meant interpreting each nucleotide as an element of the finite field $GF(4)$. There might be other uses for that particular algebraic interpretation, but it's not obvious to me.
In summary, DNA doesn't have a "natural" algebraic structure, in the sense of an algebraic interpretation which corresponds to anything chemical or biological. If it's convenient to interpret DNA using some specific algebra to solve a problem that you're faced with, go for it. But it will likely be different depending on the specific problem.
Answer: IMO speaking of algebra here is irrelevant. No computation is ever made on the strings (be them bits or quaternary digits), no boolean operation, only comparisons for equality.
Furthermore, if you somehow encode the digits 0-3 or symbolic values like A T G C, the representation will most probably end-up as the binary numbers 00 01 10 11.
By the way, all computers in the world are binary, as this system is by far the most hardware-efficient. There had been attempts to build ternary computers, but they were abandoned. A quaternary computer is out of question.
Also notice that computer registers always have an even size (most of the time a power of 2), so that bits fit in pairs.

DNA sequence and algebra


Thunderbird runs with an empty profile after I used sudo

Question: I once ran thunderbird with the sudo command and now when I run it (with or without sudo) it does not load my default profile. The files of my default profile are still in the .thunderbird directory.
Answer: You likely messed the permissions of the folders that is uses such as the cache, and it's configuration settings.
Try running the following to get back ownership of all files in your home directory, provided you are logged in as the user who cannot open Thunderbird:
sudo chown -R $USER: ~

Make sure you're in your home directory when you do this!
If you are running as another user in a multi-user environment, you must replace $USER with the user's name.
Ensure in the future that you do not run it as root again.  Similar issues can happen with other software as well. It is safer to use sudo with the -H flag : sudo -H (executable) so that the software runs in root's home directory instead of your own user's home folder.
Comment: Okay, the question did not give me any reason to think that he might want to run that from a second account, but additional clarification can never hurt.
Comment: Agreed @ByteCommander.  I try to never assume these things, mostly because I administer a large organisation :)  In fact, I would probably set the owner in a script by cycling through each /home folder and check the owner with `ls -ld ./ | awk '{print $3}'` and use that to `chown` back to the user, but I don't want to go too crazy with my answer :)
Comment: I fixed your `chown` command.
Comment: @ByteCommander Re-edited.  That's fine if you only have one user, but not in a multi-user environment where you're fixing another account's permissions.  It's always best for one-liner fixes to explicitly specify the username instead of relying on variables.
Comment: Didn't work. I don't know how to use the -p option with thunderbid exactly.
Comment: @Reza try running `thunderbird --ProfileManager` to see if you can select a profile.
Comment: I did and there is only a default profile which is empty.
Comment: @reza At this point you may need to cut your losses and uninstall/reinstall it.  It'll probably be easier in the long run.  Just make sure to delete the thunderbird folders `~/.thunderbird` as well as the Thunderbird folders in `.cache` and `.config`.


Creating a TMS from many large TIFF

Question: I have a set of several tiff:s, the largest is 4,7 MB, that I want to create a TMS out of. If I don't want to use Gdal and write commandlines is there a free software option that I can use?
Answer: One option is to install GeoServer, add your tiffs as an Image Mosaic or as simple layers (you don't say if they fit together or not) and then use GeoWebCache (builtin to GeoServer) to serve up TMS tiles.
Answer: You can upload your Tiffs into http://nextgis.com and get them back as TMS. But each raster will have separate URL. Also stacking on the fly is available (just list all raster styles in TMS url separate by commas).
Details: http://docs.nextgis.com/docs_ngcom/source/data_upload.html#raster-data
Here is an example of TMS URL: http://bushman.nextgis.com/api/component/render/tile?z=13&x=4784&y=2380&resource=36

Also you can create webmap like this: http://bushman.nextgis.com/resource/37/display

Creating a TMS from many large TIFF


Which adjective best describes a person who seeks complex ways of solving a simple problem?

Question: What adjective would best describe someone who seeks complex solutions to simple problems? For example, one who would design the tree-swing in any other of the ways described below except the last one.
Comment: The simple answer to your question is ***"overcomplicating"***. If you're looking for something else, then please clarify. Perhaps you're the one overcomplicating the matter.
Comment: What kind of description are you looking for? *Creative*, *stupid*, *complicated*, *silly*? The cartoon also doesn't necessarily imply anything other than miscommunication. We have no idea what the user *said* was wanted. Was the communication verbal? It could have been "a tree swing," completely open to interpretation, or it could have been "a tire attached to a tree branch by a rope." Or was the communication the last picture itself?
Comment: Thanks Jason, just to leave out any other factors that may be in play, you could imagine a case where you told a group of 6 guys to design a tree swing and each came up with each of the above designs. Hence, which term would describe the guys with the complex designs.
Comment: There are hundreds of possible ways to answer this. You need to be more specific as to what you're looking for.
Comment: Related: [saying that refers to not going overboard in solving a problem when a simple solution exists](https://english.stackexchange.com/questions/192235/saying-that-refers-to-not-going-overboard-in-solving-a-problem-when-a-simple-sol/192240#192240).
Answer: Rube Goldberg / Rube Goldberg-esque /  Rube Goldbergian

Rube Goldberg (adj.)

Ingeniously or unnecessarily complicated in design or construction.
A Rube Goldberg machine Oxford Languages

Accomplishing by complex means what seemingly could be done simply
A kind of Rube Goldberg contraption … with five hundred moving parts
m-w

Rube Goldberg
Attributive. Designating a device or scheme that achieves a simple
objective by exaggeratedly or absurdly complex means; unnecessarily
complicated, impracticable, or ingenious.
Rube Goldbergian adj.
The oil industry provided Rube Goldbergian ice-cutting machinery that didn't work. OED

Linguistically speaking, a Rube Goldberg contraption or Rube
Goldbergian or Rube Gold-bergesque still refers to anything
that's overly complicated, requiring twenty-five steps to accomplish
what could take two. Ralph Keyes; I Love It When You Talk Retro

Instead of using an adjective, you could also say He's a Rube Goldberg when it comes to solving problems to convey overcomplication. As one example below points out, Goldberg's inventions could work, at least in theory, whereas this isn't so for every idea in the the cartoon. Rube Goldberg addresses more your question than the cartoon's humerous "solutions."

JK put a thing together from PVC pipe, some aluminum pie plates, a
circular TV antenna, some capacitors and resistors he took from an old
computer, and a neon light starter. It looked like a Rube Goldberg
thing. CS Moulton; Murders Never Cease

It is obvious that building a Rube Goldberg solution easily
addresses Science and Technology standards, but this was a
cross-curricular project that incorporated Writing standards as well.
D. Ambrose and R. J. Sternberg; Creative Intelligence in the 21st
Century

He would often fashion a Rube Goldberg solution when he wasn't
inclined to travel to the hardware store, so I was prepared for an
interesting solution to the leak. T. .J. Lewis and C. L. Trempe; The
End of Alzheimer's

Also in the Final Destination film series the characters often die in
Rube Goldberg-esque ways. In the film The Great Mouse Detective, the villain Ratigan attempts to kill the film's heroes, Basil of Baker
Street and David Q. Dawson, with a Rube Goldberg style device.
Wikipedians (ed.); American Comic Strips Before 1918

"It all sounds like it makes sense, but the Delta system is really a
giant Rube Goldberg–esque machine," Gleick said, gesturing out the
window at a tangle of muddy canals. "They've twisted so many knobs and
pulled so many levers here that no one really knows how the Delta's
plumbing works anymore." Alex Prud'homme; The Ripple Effect

So it seems that as a nation we've devoted countless resources, time,
and energy to creating a Rube Goldberg-esque system of top-down
reform while overlooking something vitally important: Do our students
care about any of this at all? Bryan Goodwin; Building a Curious
School

He also plans to use the gun to determine just how those Rube
Goldbergian translational activators stimulate protein synthesis.
Ben Patrusky; "An Essential Intruder" in  Mosaic, Vol. 22, n.3

Goldberg, Rube (1883–1970), US cartoonist; full name Reuben Lucius
Goldberg. As creator of the comic strip characters Professor Lucifer
Gorgonzola Butts (an inventor of complex mechanical devices to achieve
simple tasks), Boob McNutt, and Lala Palooza, he satirized American
folkways and modern technology. Lexico
Answer: In British English, Heath Robinson is more common:

Heath Robinson [adjective] [British]
Ingeniously or ridiculously over-complicated in design or
construction.

[(1872–1944), English cartoonist and illustrator; full name William
Heath Robinson. He lampooned the machine age by inventing absurdly
complicated 'Heath Robinson contraptions' to perform elementary or
ridiculous actions.]

His was a Heath Robinson approach to fixing everything

[The Sunday Times; 2005]


Yosef sold into prostitution

Question: I remember hearing of a source that states that Yosef was sold into prostitution, or some other form of sexual slavery, by his brothers, and not just plain slavery as is commonly assumed. Does such a source exist?
Answer: The Jewish Virtual Library on Homosexuality states that

the Talmud records that the Egyptian Potiphar purchased Joseph "for
himself " (Sotah 13b), that is, for homosexual purposes (Rashi).

ArtScroll Gemara Sotah 13b2 and 14a1

Potiphar, a courtier of Pharoah, purchased him Rav said: This means that [Potiphar] bought [Yoseph] for himself, i.e. for his
own illicit purposes (as Rashi explains). However, Gavriel came and
emasculated him. This is derived as follows: Initially, his name
is written as "Potiphar", but in the end it is writtenn as Potiphera
The name change alludes to his transformation into a
eunuch.

Since the brothers did not sell him in Egypt (and as explained elsewhere, they did not even pull him out of the pit to sell him), they cannot be blamed for the purpose Potiphar originally had in mind when he bought him.
Answer: Not that they sold him into the sex trade, but that they thought that is where he ended up due to his beauty. See Bereishis Rabba 91 6 here, when the brothers came to Mitzraim for food, they were also keeping their eyes out to find Yosef. They headed to the area where the prostitutes were, saying our brother Yosef is is beautiful, perhaps he is there. And as Matnas Kehuna explains, perhaps he was sold there to his embarrassment.
(This precludes thinking he was there of his own accord. The term used for the prostitutes area is 'Kuba', which usually means a place for prostitutes who are held there against their will.)
Comment: This may also explain why the brothers didn't recognize Yosef (Rashi says because he had a beard), since they saw Yosef in such a negative light and could not come to terms with even the thought that he was now viceroy if Egypt.
Answer: Perhaps what you are referring to may emanate from Daat Zkenim on Genesis 39:19? (excerpt):
כדברים האלה וגו.

פירש"י בשעת תשמיש
  אמר'  לו כן. ותימה להרב משה דבמס' סוטה פריך כתיב פוטיפר וכתיב פוטיפרע
  בתחלה נקרא פוטיפר  וכשקנה יוסף קנהו למשכב זכור ונסתרס ונקרא פוטיפרע
  אלמא לא היה משמש מטתו וי"ל בשעת  תשמיש לאו דוקא אלא בשעה שעוסק בעניני
  תשמיש. ועוד י"ל שלא נסתרס לגמרי אך כשהיה רוצה  להזדקק עם יוסף היה
  מסתרס

Sefaria.org's English:

כדברים האלה, "things like this;" according to Rashi, Potiphar's wife
  showed him how Joseph had tried to arouse her while she was in bed
  with her husband. This appears difficult, as Rabbi Moshe, quoting the
  Talmud in tractate Sotah, folio 13 pointed out that the name Potiphar
  is spelled in the Torah once as פוטיפר, (39,1) without the letter ע at
  the end, and on another occasion with that letter ע missing (37,36)
  The Talmud concludes that once he had become a eunuch, as a close
  servant of Pharaoh, he could not indulge in sexual activity, so that
  Rashi's commentary seems forced, to say the least.
  and additionally there are those that say that he was not a eunuch completely but when he wanted to have relations with Yosef he became impotent.

According to this, it doesn't state that the brothers sold him for prostitution, but rather that Potiphar, the last person who bought him, bought him for sexual purposes.
Comment: That's no translation of the Hebrew you quote (but the latter does say Joseph was bought for immoral purposes).
Comment: I found it, I think. Gemara Sotah 13b.
Comment: @msh210 While, here, Sefaria, didn't do a complete translation, it seems that it got the main gist of things, I think. Happy Chanukah.
Comment: The bold section is mistranslated. It should say "and additionally there are those that say that he was not a eunuch completelybut when he wanted to have relations with Yosef he became impotent.
Comment: @sabbahillel Thanks. That's a good point. Doing copy / paste.

Yosef sold into prostitution


SEC Form 4: Statement of Changes in Beneficial Ownership [PLTR/Peter Thiel]

Question: Could someone explain to me how an insider disposed shares with "$0.00" price according to PLTR SEC Form 4? I understand the acquired shares with "$0.00" price may be given as bonuses.
Comment: You may want to link to a specific example. Otherwise it could be as simple as a "clawback" or a return of shares for other consideration in an employment contract.
Answer: From this article at geoinvesting that discusses what you might find on a Form 4:

Some of these include "FREE" or below-the-current-price instances such as options, warrants, share based compensation and other indirect transactions.

As you mention, that makes some sense for acquisitions, but isn't quite as intuitive for disposals. Yet there are cases where, for taxation or other legal reasons, shares might be given away at no cost.
In the particular case of the Palantir Form 4, the two lines in Table I that are listed as disposed at a price of $0 both reference footnote 6, which reads:

Reflects a distribution to limited partners effected pursuant to a preexisting Rule 10b5-1 plan adopted by the holder and in compliance with the Issuer's lock-up terms.

It appears that the Rule 10b5-1 plan involved a distribution from the funds (mentioned in footnotes 5 and 9) to some partners. And that may very well have been at an agreed upon price of zero.
A Form 4 for Equinix does something similar, but with a slightly more explicit explanation in the footnote. (Emphasis mine.)

On April 28, 2006, investment funds for which Crosslink serves as investment adviser or manager distributed these securities pro rata to the investors in those funds for no additional consideration, which securities previously were reported as indirectly beneficially owned by the Reporting Persons. The zero in Column 4 is a placeholder only that is required by the EDGAR software.

In summary, two funds for which Peter Thiel is the reporting person distributed shares to others, for no additional consideration. The software used to file the Form 4 doesn't have a way to represent this, so they enter $0 in that field.
I've found a few other Form 4 filings that use similar wording, although they are all in the Table II section. Nonetheless, it appears that the SEC software doesn't handle blank fields well, so the filers end up using $0 where a blank would make more sense.

The price of zero is fictional and only used for purposes of facilitating the electronic filing of this Form.

The price of zero is notional and only used for purposes of facilitating the electronic filing of this Form.

The zero ("0") in this column is a "dummy" amount, solely for the purpose of permitting the use of the following explanation: No price was applicable to the acquisition of this security.


Compact Manifold with Geodesic B0undary

Question: Suppose $(M,g)$ is a 2-dimenensional compact Riemannian manifold with boundary $S$. Furthermore, assume that $S$ is totally geodesic. Now consider the conformal change of metric $\widetilde{g}=e^{\phi}g$ for some smooth function $\phi$. In order for $\widetilde{g}$ to satisfy the condition that $S$ is still totally geodesic, then it is necessary that $\partial_N \phi=0$. Is this condition sufficient?
Answer: Yes, note that under the conformal change of metric $\tilde{g}=e^{2u}g$, the geodesic curvature changes as follows: (see p.1050 in here for example)
$$\frac{\partial u}{\partial\nu}+k_g=k_{\tilde{g}}e^u$$
where $\frac{\partial u}{\partial\nu}$ is the normal derivative of $u$.
Therefore, if $S$ is geodesic with respect to $g$ (i.e. $k_g=0$) and $\frac{\partial u}{\partial\nu}=0$, we have $k_{\tilde{g}}=0$, i.e
$S$ is geodesic with respect to $\tilde{g}$.

Compact Manifold with Geodesic B0undary


Use WordPress' URL rewrite engine

Question: I'm developing a web application with user submissions, i'm not too hot on mod-rewrite and was hoping there is a way to utilise WordPress' amazing rewrite engine and incorporate this somehow into my PHP/AJAX web application?
Comment: To clarify: you want to develop something that does not depend on WordPress, just re-use the rewrite functionality? (Use `@Jan` in your reply and I get a notification)
Comment: @Jan yeah, so each submission somehow gets treated as a post? and therefore gets a fancy url
Answer: I suggest you don't try to take out the WP_Rewrite class and re-use it in your application, but look at other frameworks instead. Many MVC frameworks have nice rewrite engines, that not only offer more flexibility in handling incoming URLs, but also generating internal links according to these formats.
The WordPress rewrite system is tightly coupled to the rest of the code, and for all the effort it would take to rip it out, you can just as easily have learned how to use a "real" framework.
Comment: Take a look of some of Mike Schinkels trac tickets to get an more in depth view of why you shouldn't use the wp rewrite engine
Answer: You need to know a bit about regular expressions, but you can add your own rewrite rules and variables. There's some good examples and documentation here:
http://codex.wordpress.org/Function_Reference/WP_Rewrite
Sorry, I've just reread your question and realised that you want to use Wordpress URL rewriting in an external application. I wouldn't bother doing that if I was you. Either build the whole thing in Wordpress or look at using a framework like Symfony, CodeIgniter or if you want something more simple, Nimble

Use WordPress' URL rewrite engine


Evolution of Android testing methods

Question: I'm doing a research on Android testing methods and their evolution in time. Could someone point me in the right direction (recent articles, books) I'm finding a lot of material surfing blindly but it's hard to distinguish between obsolete methodologies and not.
What is the current state of the art in Android testing?
Comment: Means? You want to know detail knowledge that how to do android app testing?
Answer: The really good source of information related not only about testing on Android platform but mobile testing in general is "Hands-On Mobile App Testing" book by Daniel Knott.
It'll give you a general idea on how to approach to mobile testing and which techniques to use. Moreover it has plenty of information regarding testing tools which are currently trending on the market.

Evolution of Android testing methods


Why does the listing of returnees in Ezra change from families to territories?

Question: In Ezra 2:21 the listing of the returnees from Bavel to Eretz Yisrael switches from lists of families to peoples from specific areas in Eretz Yisrael (the commentary of Daat Mikra identifies nearly all of the locations). I would like to know the reason for this change in identifier.
Answer: Malbim on the verse writes:

"בני בית לחם, אלה שהיו כולם ממשפחה אחת אף שישבו בכמה ערים צרף מספרם ע"ש ראש המשפחה, ואם לא התקבצו ממשפחה צרפם ע"ש העיר שגרו שם תחלה."

Translation: "The sons of Beit Lechem, those who were all of one family even if they lived in several cities he added their numbers together under the name of the head of the family, and if they didn't gather from one specific family he counted them together under the name of the city they lived in originally [that is, prior to the exile]."
According to Prof. Yehoshua Grintz in "Mechkarim Bamikra" (Studies in the Bible), pg. 179, the cities of Yehudah were badly destroyed by the Babylonians while the cities of Binyamin were considerably less so, so the people of Binyamin were able to return to their own cities, while the people of Yehudah had to rebuild practically from scratch. Because they had no cities (yet), they identified per family and not per city.


Does Google Wallet offer an API for generating Virtual OneTime Cards for use by 3rd party commerce platforms?

Question: A client of mine has a very interesting use case:
Enabling consumers to be issued a temporary one-time use debit card number for purchasing goods on 3rd party retailers. Think pinterest for shopping, enabling one to ping goods from 3rd party retailers, and have a digital wallet for the purpose of purchasing pinned goods. The key is that the 3rd party retailer does not necessarily implement an existing wallet solution, like google wallet. Think luxury goods.
It seems that Google Wallet sort of, kind of, enables such a use case via its Virtual OneTime Cards. However, I could not find any indication of API endpoints that would work sort of like this:
Issue a POST to wallet.google.com/virtual_card with customer data, get back a 16-digit debit card number, that may then be used by customer to purchase items on 3rd party retailer sites.
It also seems that AMEX Serve has some kind of beta program in the works: http://techcrunch.com/2011/10/09/american-express-to-release-an-api-for-digital-wallet-platform-serve-focuses-on-data-and-personalization/
Visa has v.me.
Of course, it doesn't seem like any of these services have APIs for issuing temporary debit cards.
Am I missing something?
Answer: The Google Wallet for online commerce API is probably what you're looking for:
https://developers.google.com/commerce/wallet/online/faq
https://developers.google.com/commerce/wallet/online/overview


Jumps up and down

Question: As an English-speaker I would be tempted to translate "Jack jumps up and down" into Jack springt auf und ab, but the English use of "up and down" seems idiomatic and my literal translation might be totally wrong. How does "Jack jumps up and down" get translated? Are there different ways of saying this in German? I've also seen in die Luft (zu) springen, or ständig aufspringen which to my American ears seems the more "German" way of saying it.
Comment: What would you say does "Jack jumps up and down" mean?
Comment: A good, idiomatic phrasing totally depends on context. You should provide more context to your sample sentece. Who is Jack? Why and where does he behave that way?
Answer: The key to translating this idiom is using the verb hüpfen (to hop, to skip, to frisk) instead of the verb springen.
Jack jumps up and down.

Jack hüpft auf und ab.

This is exactly the same picture as the English expression. The alternative

Jack springt vor Freude. (or Jack hüpft vor Freude.)

is very formal und sounds right only in narration. Then usually in Präteritum tense of course.
(Note there's another verb hoppeln which also means to hop. That's what bunnies do, people with a leg injury, and cars with broken suspension. A third verb hopsen means to skip in its narrowest sense. Hüpfen is a catch-all.)
Comment: I was worried that a German would think, yes, I can jump up, but there is no such thing as jumping down once you've jumped up and are at the zenith of your jump. I think I like *Jack hüpft vor Freude*, despite the poetic Klang.
Comment: *Poetic Klang* sounds like the name of a deceased Klingonian Emperor, who sang verses to the glow of a burning planet.

Jumps up and down


How can I get cheats working on the My Boy! emulator?

Question: Are cheats available on the free version of "My Boy!", a GBA emulator for Android? I have pokemon light platinum and wanted to use some cheats. Through extreme trial and error I haven't been able to get a cheat to work. Is it because I have the free version?
Answer: See the developer's page for more info. Quoting from the source:

What cheat systems are supported?

GameShark v1&v3 (As far as we know, Action Replay code is just GameShark v3). Format: XXXXXXXX YYYYYYYY
Code Breaker. Format: XXXXXXXX YYYY
Raw code. Format could be one of the following:

XXXXXXXX YY
XXXXXXXX YYYY
XXXXXXXX YYYYYYYY

OK, but where do I input cheat codes?
While you are in a game, select MENU -> Cheats.
I can't seem to get cheats to work. Why?
Well, good question! it could be quite a number of reasons:

The cheat codes were not invented for your game, or your specific version of the game. There are often multiple variants of a single game.  For example, cheats created for [1.0] of the game have little chance to be able to work on [1.1]. In this case, it may crash the game, cause graphics glitches, or simply do not work at all. Believe me, this is the number one reason why people can't get cheats to work.
You may not mix different types of cheats. For example, Code Breaker master code may make GameShark cheat codes not to work.
Some cheat codes have preconditions. For example, some are activated only when you are holding down certain buttons. Read the instructions carefully.
If your cheat codes are for GameShark v1, or raw code, do not select "Auto detect" for code type. Select the right type explicitly.
Your cheats are just wrong codes that are not supposed to work.
There is a bug in My Boy!. Please report to us by email. Seriously this should be the last thing you consider, since the cheats system turned out to be robust.

As Pokemon Light Platinum is a Pokemon Ruby hack, chances are that you are trying to use the wrong codes.
Answer: No, it does not support Action Replay codes.
Answer: So far i've noticed that code breaker cheats work while gameshark v3 (action replay) rarely work. i am playing final fantasy tactics advance and my gameshark v3 codes do not work, auto select said they were valid codes but would never work. i finally got the cheats to work after reading the above text from the developer "You may not mix different types of cheats. For example, Code Breaker master code may make GameShark cheat codes not to work."


How to Import Shapefiles (or any dataset) to a webmap using Openlayers/GeoExt online? WFS-T

Question: I tried Using Heron, But it didn't workout well. The problem is, I couldn't found any good documentation about this matter. I just want to "Update" DataSet using an UpLoad tool to my actual Database.
I'm using GeoExt 1 / ExtJs 3.4 / Openlayers 2 and Geoserver.
Answer: You can load the Shapefile into QGIS, then export a webmap (Openlayers or Leaflet) using the qgis2web plugin. It also allows you to upload directly to the web via FTP.


What if I ask for death since I fear sinning

Question: Is it permissible in this case? I have been looking around but can't find an asnwer
Answer: Asking for death to Allah or anyone else is generally considered to be a serious sin. This is because Muslims view life as a precious gift from Allah and asking for death may be seen as a rejection of this gift. Additionally, suicide is strictly prohibited in Islam, as taking one's own life goes against the belief that life is sacred and that Allah is the only one who has the right to determine the length of a person's life.


What is the difference between data link layer and sub data link layer

Question: Why does data link layer have sub layer but other layers don't have sub layer.
Comment: Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
Answer: The concept of "layers" is an aid to thinking about networking, about where network functions are best implemented. It's not a hard-and-fast set of requirements: the ISO and IETF family of protocols even have different notions of how many layers there are, and which functions belong in each layer. The implementation of a modern ethernet controller breaks layering really hard, but the concept of layers is still use in thinking about what that controller is doing. Remember that it is just a "model", an abstract and simplifing description of the real world as an aid to thought.
It's generally held that link layers need a "sublayer" to implement the near-but-not-really-electrical nitty gritty: detecting the start and end of packets, detecting media availability, manipulating the bit arrangements so that DC bias to be held within bounds, detecting and correcting errors, some sorts of encryption. And between this nitty gritty and the link layer proper we often want some signalling channel: the SONET overhead, the Ethernet autonegotiation and OAM. A lot of the determination of if a function is in the link layer or sublayer depends how we implement the feature. So the definition of sublayer functions gets extremely wobbly.
The same is true for other layers as well. Rather than call these "sublayers" they are usually called "x.5" layers. So ATM, MPLS and some tunnels are "Layer 2.5" as they present a link layer service implemented using network-layer services.
Edit: "near-but-not-really-electrical nitty gritty" might be better described as "electrical concerns addressed by the link layer plus computing functions needed to establish the link later, implemented out-of-band".


run script remotely on windows 2012 server

Question: I have a script that I manually have to run 4 or 5 times a day, in one of our servers. I remotely access the server and execute the script.
The OS is Windows Server 2012 R2 Foundation.
Now, I can´t give remote access to the server to the other users, but I need one of the users to execute this same script. Is there a way, i was thinking of a script, that when that other user executes it, it runs the script lodged in the server?
Answer: While totally overkill for your need, Jenkins could provide a web interface to run a "build" that would be your script.  The script could have admin access (as an example) but the user would only have access to Jenkins.
Another option, you could have a parent script running as a schedule task every couple of minutes.  Have it check for the presence of a file in a file share and if that file exists, run the script you want to run.  All that would require is a parent script and a locked down file share.
Comment: Thanks Eric. Going to give it a go with Jenkins. I have a task created in that server to run the script automatically every 15 minutes, thing is it does not run, and I can't get it to run i don't know why...


How do I open a local file through Remote Desktop?

Question: Is it possible to open a file in a Remote Desktop session locally?
For example, I have a Word document in the remote session and want to open directly to local without downloading. Would this be possible?
Answer: I don't think this is possible.
(I am kinda wishing this answer could get voted down as being wrong as it would be a handy feature, especially when the remote machine does not have word or excel) but I have been using RD for years (maybe decades?) and have never seen or header anything like this).
There is an option to allow you to share your local drives and hence you can access them when you are inside the remote desktop session, but not the other way around.
If the computer you are connecting to is on your local windows network and you have the appropriate permissions, it may be possible to access it using standard windows shares.
Otherwise, I think you have to copy the file to your local hard-disk and then switch back to your desktop and open the local copy. Since this is a copy, you have to copy it back to the remote computer if you make changes, and also make sure no-one has changed the file in between times.
Comment: As far as I know there is no reverse version of the drive sharing.
Comment: what would a reverse version look like?  I don't get it. A local computer can see the remote computers drives with "my computer". And from remote desktop as you mention, a local computer can in a remote desktop session, see its own drives even while in the remote session. So what is it that is not getting shared?


How can I unstick my trackpad button?

Question: The trackpad button on my 2007 Macbook Pro seems to be sticking.  Specifically, it's stuck in the "down" position, which means I'm selecting pretty much everything all the time (you wouldn't believe how frustrating it was just to ask this question).  It was fine yesterday.  What can I do to unstick it?
Comment: Can you determine if it's a software or hardware issue? What happens if you boot into the Mac OS installer, or some other bootable CD?
Answer: The trackpad getting stuck is also a well known symptom of a bulging battery in the MacBook Pros of this generation. I'm dealing with this issue myself and am very annoyed about it too, because this 2007 Santa Rosa MBP I paid for is essentially the most lemon computer I've ever owned (at least four other hardware failures besides this one).
Comment: We appreciate your opinion, but the condescending vitrol really doesn't help. I had this problem in my second of four apple laptop's I've ever had, and there was other notable stress damage on the laptop (bulging case, etc.). Despite my laptop being well out of warranty, the Genius replaced mine free of charge. Problems happen, things go wrong, the company that gives everything away goes out of business. The unfortunate thing is, you quite possibly have the "correct" answer in this question, I admit.
Comment: I'm happy you mentioned bulging batteries, thanks lkraav, very informative.  I had enormous difficulties with the power system in my old 2007 MBP, that machine ate 6+ hard drives, 3-4 batteries, and 4-5 power supplies over 4 years.  I never had the patience to let a battery bulge though, sounds like I made the right decisions
Answer: This is going to sound dumb, but have you restarted the Mac? I've had this issue on my Magic Trackpad a couple of times and the only way I was able to cure it was with a simple restart. (At first I thought it might be because I also ran MagicPrefs, but I've since removed that and the problem still occurs sometimes).
If you find a restart 'fixes' it, as I have done in the past, then it's possible that it's the software getting confused rather than a physical issue. I haven't found a Terminal invocation yet to restart the mouse driver part of the Mac but I reckon that if I found one I could probably use that to unstick the pad when the problem arises.
Comment: As you read around, this defect is actually a very common problem in all Mac laptops and mac trackpads of a certain generation. It no longer occurs in newer models. Apple really should do a recall and repair, but that would cost them too much, I guess.
Answer: I had the same exact problem and it was almost unbearable to search for help. I took out the battery but kept my MacBook connected to the adaptor and, go figure, it works like a charm. Time for a new battery! The bulging on my battery is very noticeable.
Answer: In most models there's a screw directly beneath the trackpad that influences how hard/soft the click should be. If you have the right tools to open it up, you could try turning it a bit to see what happens.
What you can try first is to press down on the button, hold it down, move your finger from left to right a few times and then let it go again. Sometimes this fixes it, but if somethings really broken or worn it probably won't work.
Comment: I tried the loosening of the screw below the multitouch touchpad and it felt good clicking on it. Noticed battery was bulging right around location of the touchpad too. After screwing everything back in and testing ... one side of the touchpad is still extremely hard to press. Time to order a new battery and see if that resolves the issue. Thanks.
Comment: What you can try first is to press down on the button, hold it down, move your finger from left to right a few times and then let it go again. Sometimes this fixes it... Thanks Alec It totally worked. Saved me a lot of frustration
Answer: I've had an iBook g4 that had this "Issue"... it turned out a cookie crumble got stuck in the space between trackpad and case (don't ask). Clicking a few times on different places on the trackpad and some canned air fixed it. Might be worth a try before you pop out the screwdrivers.
Answer: I had something similar happen to my Macbook pro 2010.  I fixed it by:

Open system preferences
Click Trackpad
Uncheck Tap to click, Dragging, Drag lock, secondary click

Not sure if this is the same on a 2007 model.

How can I unstick my trackpad button?


When the topic of transport decarbonization comes up, all I hear is batteries and hydrogen. But what about renewable natural gas (RNG)?

Question: When the topic of transport decarbonization comes up, all I hear is batteries and hydrogen. But what about renewable natural gas (RNG)? The milage is better, less energy loss, as I understand. You can refill it in an instant (unlike recharging your Tesla). Plus, you can make your own fuel by decomposing your food waste and poo in your anaerobical digester in the backyard, it's also an advantage. What's the catch?
Answer: Leakage.
Hydrogen isn't a greenhouse gas.  If it escapes into the atmosphere, no big deal: it'll either combine with oxygen to produce water, or it'll reach the outer atmosphere and escape.  Either way, no global warming effect.
Methane is a rather potent greenhouse gas, second only to carbon dioxide (it has a stronger effect, but doesn't last as long -- and it combines with atmospheric oxygen to produce carbon dioxide).  Any leaks during production or use will make global warming worse, not better.
Comment: Liquefied natural gas is less likely to leak, but if it does leak, the effects are the same as with the gaseous form.
Comment: Does it apply to its liquified form too?
Comment: Liquefied natural gas is more likely to leak. You can liquify natural gas only if you make it very cold. The trouble is, it won't stay cold forever. Heat is slowly leaking into the liquid natural gas container, which makes the liquid gas due to evaporation. The pressure starts to build up. If you aren't prepared to consume the produced gaseous natural gas as quickly as it is being produced, the only solution to prevent a pressure explosion is to vent that gaseous natural gas into atmosphere. Thus, liquid natural gas slowly leaks, even in ideal conditions. Pressurized natural gas never does it.
Answer: Renewable natural gas ain't happening, ever, at the scales required.
We are using massive amounts of mobile energy as gasoline and diesel. The only feasible way to replace that is a generation mix of onshore wind, offshore wind, solar, nuclear, hydropower and maybe little (but very little) natural gas should hydropower and nuclear be incapable of meeting the momentary demand in the electric grid. About the only feasible way to store that energy in mobile sources is batteries. Hydrogen has very poor electricity-to-hydrogen-back-to-electricity-again efficiency (about 38% as opposed to over 90% of batteries), electrolysis cells are expensive, fuel cells are expensive and have a short lifetime, and storage of hydrogen is difficult due to it having very poor volumetric energy density. Therefore, the total cost of a hydrogen solution would probably be higher than what the market expects from the gasoline and diesel replacement technology. Batteries, on the other hand, have been demonstrated to be economically viable, and carmakers are adopting batteries as the definite solution.
The problem of renewable natural gas is that it releases carbon. Where do you get it if you create "renewable natural gas"? From carbon dioxide, naturally, combined with hydrogen produced using electrolysis. Combusting fossil fuels to get carbon dioxide is counterproductive. Atmospheric carbon dioxide capture is too expensive due to the low concentration of carbon dioxide in the atmosphere. If you capture carbon dioxide from office spaces where the concentration is higher (about double that of general atmospheric concentration), you make the economics of carbon dioxide capture from air more favorable but then you run into the problem that there aren't enough humans to breathe enough carbon dioxide. So about the only way to get sustainable carbon dioxide is from combustion of biofuels. The trouble is, we don't have enough biofuels to create enough carbon dioxide. Not only that, but if carbon dioxide of biofuels is captured from stationary sources like forestry industry plants, you could directly store that carbon dioxide underground (BioCCS) as opposed to creating "renewable natural gas" for combustion in cars where it would release its carbon dioxide back to the atmosphere. So claiming the product is "renewable" is silly because there's a far better place for that carbon -- under ground, not in atmosphere. Thus, so-called "renewable natural gas" contributes to the global warming problem due to atmospheric carbon dioxide.
Thus, the only solutions feasible are solutions that emit zero carbon dioxide. Those are basically hydrogen and batteries. It seems batteries are winning.
Comment: But if the feed is plant-based (e.g. food waste, seaweed), it's net-zero
Comment: Yes, it is. However, there is not enough plant-based feed available.
Comment: ...and besides, you could store the plants underground in anaerobic conditions to capture the carbon. You could also burn them directly for energy, capture the carbon dioxide, and store the carbon dioxide underground. However, if you create methane and sell it for use in mobile sources like cars, they will emit the carbon dioxide directly to atmosphere, with no possibility to capture it.
Comment: Seaweed. 6 more to go...
Comment: If it's a closed loop, no biggie. We need to make our emissions net-zero, not our atmospheric CO2 concentration


oracle tablespace extending

Question: While under massive write (insert and create table as) load, when Oracle RAC needs to extend tablespace, all write activity gets blocked for however long it takes it to finish extending (tens of minutes), with all sessions blocked by "data file init write".  Is there way to configure Oracle to extend the file proactively so that things can keep moving while it is doing it?
Comment: Tens of minutes sounds incredibly long. Why don't you preallocate?
Comment: @Mat well, yeah, we are going to try to preallocate, but I'd like to know 1) is it normal for this to take 30 minutes to extend by 1Tb 2) is it normal that all writing stops?  Can it pre-extend before it really needs it to avoid stopping?
Comment: Yes, extending by 1T can take a while, depending on your I/O system. Not sure how the locking works there though - 1T extent is pretty huge, it's usually done in smaller chunks (meaning disruptions are shorter, but total time spent extending probably a bit longer).
Answer: 30min for 1TB is quite normal. That all writing stops is also normal if your tablespace completely run out of space. When writes has nowhere to go they have to wait for the RESIZE operation to complete. If one extends datafile while there is still space in it database I/O does not stop.
Just why you extended for such huge amount? Now those +1TB will add to your RMAN backup. Of course they will compress well but still not 100% and RMAN will need time to read all those blocks.
I would setup autoextend on those tablespaces:
ALTER DATABASE DATAFILE '+DG/sid/datafile/datafile_01.dbf' AUTOEXTEND ON NEXT 10G MAXSIZE 30G
Then you would not get wasted space in tablespace and also even in case your data grows fast and catches up with autoextend operation - there will be only small delay in writes because 10GB will not take a long time to format.
And Oracle will autoextend tablespace proactively. It will not wait for the last blocks to fill up.
Comment: So how do I tell it to autoextend before it runs out of tablespace?
Comment: Did not find such information. Basically if you expect such bursts of data load and cannot have writes delayed for some time - monitor and preextend tablespace. Otherwise I never had problems while autoextending in 1-2-10GB chunks.
Answer: We solved this at my previous company by scheduling a cron job for out of trading hours to grow the tablespace when it fell to within a couple of standard deviations of average daily growth free. I researched it extensively at the time, and there is no way to tune the threshold for when Oracle does it (and you probably wouldn't want to anyway, since you still couldn't guarantee it wouldn't hammer you at the wrong time). We could have used this mechanism exclusively and turned autoextend off completely, but we thought that pausing to autoextend during the day was at least better than running out of space altogether. It can be hard to make the judgement objectively tho' since Oracle doesn't log autoextending events anywhere (at least not as of 10g which we were on then).
Another job checked the max sizes of all the autoextending DBFs, and compared it to the space actually free on the disk, to make sure we weren't overcommitting.
Comment: you would think that Oracle could handle such a basic thing, eh?  11g _still_ doesn't log extends!!

oracle tablespace extending


Blender 2.8 VSE scene strip preview does not show image (as plane) from 3D viewport

Question: In scene1 I have a simple image as plane + some extruded text; eg the title. The number of frames is set to 90. When I add a this scene strip in the VSE, I can only preview the text. The image itself is displayed as a white plane. When I add a camera and render a frame of this strip, I can see both the image and the title. Is it possible to preview also the image in the VSE while scrubbing through the strip?
Answer: You should open Properties panel (press N), select scene strip, then find in Properties panel Scene Preview/render tab. You can set here Render or LookDev to view the textures
Note, Sequencer must be in Preview or Sequenser/Preview mode

Comment: I can't find this Scene Preview/Render tab. Scene > Filter > Annotations > Custom properties. No scene preview/Render or Safe Areas tab. I' m working in the latest version (2.8.51). Is your screenshot from a previous version? Or am I missing something?
Comment: Sequencer must be in **Preview** or **Sequenser/Preview** mode
Comment: Great! Thanks. In the default Video editing workspace, you can set the Properties panel of the top window; where you can see/preview your video. This window is already in Preview mode.


Interactions between Oblivion Sower and counter spells that make you pay mana to prevent them?

Question: Lets say I am casting Oblivion Sower. The on-cast effect would activate, exiling the top 4 cards of my opponents deck. The person decides to cast Mana Leak to counter my creature. Assuming I don't have enough mana to prevent the Mana Leak on my own, could I tap the lands, assuming I get three, that are exiled with Oblivion Sower to prevent Mana Leak from countering my creature?
Comment: Today I learned that "in response to" is an actual phrase in the comprehensive rules glossary (I always thought it was player slang). It means to cast something while another object is on the stack. In this case you have *two* objects on the stack, and so the question needs clarification. When exactly did your opponent cast Mana Leak? Before, or after Oblivion Sower's trigger resolved?
Comment: @Rainbolt it was a more casual game, so I don't think we truly specified. Also probably because we didn't really separate the on cast trigger and the spell itself. We are still learning.
Answer: It depends on exactly when your opponent casts Mana Leak; he can prevent you from doing so.
Your opponent has 2 options here... cast Mana Leak in response to the "when you cast" triggered ability, or to wait until that ability resolves, and then cast Mana Leak in response to the Oblivion Sower instead.
When you cast Oblivion Sower, the "when you cast" ability will go on the stack on top of the Oblivion Sower. At this point your opponent could cast Mana Leak on top of both of them, and the triggered ability will not have resolved yet, so you will not have those lands.
Note that even if Oblivion Sower is countered, the triggered ability will still resolve normally and you will still get the lands.
Comment: Okay, so Oblivion Sower gets countered first, and I must pay the mana right then and there. And once the counter spell has finished on the stack, then the on cast effect would happen? So technically they could counter a spell after the on cast effect but still counter the spell, or they could counter it before the on cast effect, though it would still resolve.
Comment: @ShadowZ. does the explanation in my answer below help? I tried to be thorough and break it down step by step.
Comment: @ShadowZ. `Okay, so Oblivion Sower gets countered first, and I must pay the mana right then and there.` No. If you allowed Oblivion Sower to be countered, then you already lost your chance to pay for Mana Leak. You either pay, or the spell is countered. The two options are mutually exclusive. `[...] then the on cast effect would happen?` As the answer states, the on cast trigger happens regardless.
Answer: You would not be able to use the lands gained by Oblivion Sower to pay Mana Leak's cost.
The reason for this is that you will not have those lands when you need to Pay Mana Leak's cost.
Here is the interaction broken down step by step, assuming proper play from your opponent:

You cast Oblivion Sower, it's ability goes onto the stack on top of it.
Your Opponent responds to your spell by casting Mana Leak targeting your Oblivion Sower, Mana leak goes onto the stack on top of Oblivion Sowers Ability.
Assuming no responses, the stack will now begin to resolve the spells/abilities.
Mana Leak resolves, you must now pay the 3 generic mana or have your oblivion sower countered.
The on-cast ability of Oblivion Sower resolves, you would now get your lands.
If you paid the costs for Mana Leak, your Oblivion Sower would now resolve and enter the battlefield.

As you can see, at the time you need to pay Mana Leak's costs Oblivion Sower's ability is still on the stack, so no fresh lands for you (yet). It is also not possible for you opponent to respond to the Oblivion Sower before the cast trigger is on the stack, as no player is given priority when Oblivion Sower is cast until after its on cast ability goes onto the stack.

601.2i: Once the steps described in 601.2a–h are completed, effects that modify the characteristics of the spell as it's cast are applied, then the spell becomes cast. Any abilities that trigger when a spell is cast or put onto the stack trigger at this time. If the spell's controller had priority before casting it, he or she gets priority.

However your opponent can wait until after the Oblivion Sower's on cast ability resolves and then cast Mana Leak. In that situation you will have the lands, but this would have to be a deliberate choice by your opponent so it is unlikely for that to happen.
An Interesting note to keep in mind is that you will get the lands regardless of whether or not Oblivion Sower is succesfully countered, since the ability is triggered on cast.
Comment: I'm sorry but I don't understand why the on-cast ability doesn't go on the stack in step 3.
Comment: @sinsedrix "603.2. Whenever a game event or game state matches a triggered ability's trigger event, that ability automatically triggers. The ability doesn't do anything at this point." and "603.3. Once an ability has triggered, its controller puts it on the stack as an object that's not a card the next time a player would receive priority." The trigger happens _as you cast_ the Oblivion Sower, because that's what it says on the card. Then the next time any player gets priority, which is the moment you've finished casting the Oblivion Sower, the triggered ability goes on the stack.
Comment: @sinsedrix No need to be sorry, everyone is here to help answer questions and understand MTG. Did @ Arthur's explanation help, or is there something else you need clarified? If you think the question is big/complicated enough feel free to ask it as a new question.
Comment: Thanks @Malco,it's maybe a bit tricky for me. The statement "that ability automatically triggers.The ability doesn't do anything at this point" seems contractictory and set me confused. Also, I'm not at ease with the "priority" concept.
Comment: There is a really good answer that might help you understand things over here: [In plain English, how does casting spells and using creature abilities work with the stack and priority?](https://boardgames.stackexchange.com/questions/12652/in-plain-english-how-does-casting-spells-and-using-creature-abilities-work-with)
Timing and priority is the back bone of MTG as it lets us know when you are allowed or not allowed to preform an action, it can be tough to understand the fiddly-bits of it. Most of the time you just need a basic understanding though.


turn text upside down when using text on path on Sketch 3

Question: I am currently creating a dial in Sketch 3:

I have used Sketch 3's text on path feature to fit the text onto the circular dial. However, the text's orientation is actually upside down from what I want it to be—I would like the number on the bottom of the dial to appear upside down and the numbers at the top, next to the white triangle selector to be right side up.
How would I go about doing this?
Edit: I have so far tried to rotate the text by 180° to make it upside down, but when I put the text on the path it doesn't matter. I have also tried putting the text on the inside grey path and using Layer > Paths > Reverse Order to get the text to go around the outside of the path, however this doesn't seem to work because the text looks to connected to the grey path, and I would like it to appear more elevated.
Answer: So, as I understand you want to come up with this shape:

Create text with numbers, I used 30 font size with 4 spaces between numbers. 4 spaces I think for such font size is comfort space to look ok on oval.
5    4    3    2    1    10    9    8    7    6
Notice that number 6 is placed in the end of the row. It is because we want to place 6 strictly above the oval.
Make sure Width property is in Auto mode.

Text shape width plus additional one space between numbers is a circuit length for oval.
In my case text shape width is 470 px, space between numbers is 146 - 111 = 35 px.
The length of the oval should be 470 + 35 = 505 px, to calculate the diameter (width) of the oval lets use this formula pi(3.14) * D(diameter) = length of the oval.
So D(diameter) = 505 / 3.14 = 160.8 px.
Also make sure border position property of the oval is set to Inside.
Create Oval with the calculated width and equal height (160.8 px).
Place it under text in layers menu. Select text shape go to menu Type > Text on path.
Now slowly move text shape above oval you will se that text inserted inside the circle:

To make text outside the circle, select oval shape and press flip vertically in Inspector view:

Next, slightly move text shape to the rigth so 6 number goes strictly above the oval (I used guide to align the text) and don't forget that text shape width should be in Auto mode:

Now it's time to add small space between bottom border of the numbers and inner oval.
I created copy of the oval named it Inner oval decrease size of it by dragging one of the corners and pressing Shift + Alt so it will stay on place.
Additinally I created black oval with no fill and black thick border, named in Black oval.
Hide the first oval by pressing eye in front of it on the layers menu.

Adding white triangle and red background is simple.
Final result:

Sketch file
Comment: FYI, today in v.49 there is no longer a text width auto option in the inspector. Instead, it is alignment = auto
However, despite this, I was able to get similar results. Thank you for the tutorial!


Can't get Skype to shut up when signing off

Question: I use Ubuntu 12.04 and I don't want Skype to play a sound file each time I sign on, off, receive a text message, etc. So I made fitting settings in the options menu, and it works for everything except for "Skype Logout". Reinstalling didn't work. Here are the things that I tried to do to shut it up: I unticked the box that says "play sound file". At first it worked, but after I had restarted it played the sound file again. Then I made an mp3 which had no sound in it and told skype to play that file. Same thing. First it worked but as soon as I restarted, it made the sound again. 3rd thing I tried: I unticked the box that says "Enable Event". Same results. How can I fix this?
Answer: You could always delete the sound file. I couldn't get Skype to stop playing the sound either so that what I ended up doing. The sound files are located under <code>/usr/share/skype/sounds/</code>


Sentiment Analysis on the first 100 words of a very large essay of 500/700 words

Question: Are there any potential issues on performing sentiment analysis using the first 100 words of a very large essay that is of 500 to 700 words. I am having to do this because since most transformer models have a upper limit of 500 words.
Answer:
Are there any potential issues on performing sentiment analysis using the first 100 words?

No. You could do it and probably get away with it in certain instances. But if proper/accurate results are your aim, this might give you False results.
Why do you want to select only the first 100 words? As you mention, transformers token limit is 500 words. So why limit yourself to 100?
Also you can use more than 500 by some basic NLP preprocessing techniques. Just remove the stop words, punctuation marks, numbers, URL's and extra whitespaces.
All the above steps would have two fold advantage. It will increase your model accuracy and also decrease the total word length of your text.
Comment: Thank you, appreciate your insights!


Which group adhears to the idea of heavenly amnesia?

Question: Ok related to this questions Will people in hell be able to remember people in heaven? , either some individuals or indeed whole groups believe in some form of (for lack of a better term) "heavenly amnesia" where you have no memory of your life once you get into Heaven. Where did this idea come from? Is there any group that officially holds this position to be true, or is it some folklore. (I only say this because the first time I heard about it was from the old folk tale where death is trapped in a bag)
As was expressed in the other question scripture refutes this, but there are groups out their that believe things other than the scripture and use them to explain away plenty of other things.
How widespread is this idea?
Comment: I deleted my answer, because on reading Jay's, that is what people who believe this always say.
Answer: The Bible says that there is no sadness in Heaven, e.g. Revelation 21:4 "And God will wipe away every tear from their eyes; there shall be no more death, nor sorrow, nor crying. There shall be no more pain, for the former things have passed away."
So a common argument goes: There is no sadness in Heaven. If I knew that this person I loved was in Hell that would certainly make me very sad. Therefore it must be that I won't remember them.
To the best of my knowledge there is no more specific Scriptural basis for this theory. And thus I think it's weak. I can easily think of other alternatives.
To take a personal example: My wife left me years ago. In my opinion, she made a real mess of her life, can't hold a job, gone through a series of men, etc. The kids and I feel sorry for her, but for the most part we basically say, "She did this to herself. This is the life she wanted." Okay, some of that is resentment for personal hurts. But if I was a perfect human being, would I being crying for her every day and being miserable because of what she's done to herself? Or at some point is it reasonable and normal to say, "I tried to help you, but you made your choices." This appears to be God's attitude toward sinners. Of course he went way further than I have ever gone for anybody, allowing himself to be tortured to death to save anyone who would accept his offer. But those that don't, eventually he says, "So be it." I think it is plausible that in Heaven we will have a perfect understanding of justice. People are in Hell because of choices they made.
That said, there is one scenario that does really disturb me. My mother once said, what happens if she gets to Heaven, she stands before the judgment seat of Christ and he says yes, you are among the saved. Then the next person comes up and Christ says, No, you are condemned. And then this person turns to her and says, You knew how to be saved, but you never told me?
Comment: `Is there any group that officially holds this position to be true, or is it some folklore` `How widespread is this idea?`
Comment: I doubt someone being dragged down to hell will have the presence of mind to accuse anyone who is saved. That's a silly superstition. They're going to be in shock to the point of being speechless. "And he saith unto him, Friend, how camest thou in hither not having a wedding garment? And he was speechless." (Matthew 22:12) Nor do I think God would allow it: *he shall wipe away all tears*
Comment: What if it is not the person who asks, but Jesus himself: and adds to it "even after I told you to".
Comment: @davidbrainerd Well, I'm not going to argue much about the plausibility of a hypothetical scenario where so much is outside our knowledge. But when criminals are sentenced to death, sometimes they stand there speechless and in shock, and sometimes they scream curses at everyone around. Maybe that scenario is impossible ... but maybe not.
Comment: Many conservative Christians believe this idea to be true. I am not aware of it being part of the statement of faith or creed or otherwise being an "official" doctrinal position of any denomination or other organized group, but I don't claim to know the official positions of every denomination on every issue. To the best of my knowledge, this is not a central tenet of any church's doctrine, i.e. many churches have a committed position on Biblical inerrancy, the virgin birth, celibacy of priests, etc, but I don't know of any committed to "amnesia about Hell".
Comment: PS I gladly yield to someone who can point to any specific official statement from a denomination or other organization.


How can I pay a fine I was charged with in Italy while I am now in Budapest?

Question: I am a student in Budapest. I was in Italy in Milano, and I bought a ticket in the underground to go to Sesto to catch my bus to Venice. Unfortunately, I bought a wrong ticket as I did not know that Sesto was outside Milano. The conductor at Sesto checked my ticket and gave me a fine. I explained to him that I am not Italian and I do not know that Sesto is outside Milano, and he still insisted that I pay. I did not have enough money. So, he gave me a check with fine and told me that I can pay when I come back to Budapest in the Posta. Yesterday, I went to the Posta in Budapest to pay. But, unfortunately, they did not accept and told me I cannot pay at the Posta. can anyone advise on how I can pay the fine?
Comment: Unless he got your real address, I would honestly leave it. I already have one French and two German train fines - the simple fact is they're not going to waste resources to track you down and convince the authorities where you live to have you prosecuted.
Comment: Did the conductor write down your name, address etc?
Comment: As soon as the conductor got the OP's national ID number or taxcode, then the company is able to hire a debt collecting agency to reclaim the amount, since Budapest is in EU and debt collection agreements are now active and mutual among all countries. The bus company may still, upon their discretion, decide not to proceed with collection if their fees are excessive.
Answer: First, if you gave them your actual address, they might mail you regarding this, but they might as well give up on the fine. The payment process at the "posta" refers to Italian post offices only. Should you plan another trip to Italy soon, you might solve it then.
Finally, if you want to be over-correct and get this solved, you can contact their "Customer Support" regarding ticketing fines. I would not count on them being able or willing to correspond in any language other than Italian.

Direzione Sosta e Parcheggi e Supporto Clienti
Ufficio Supporto Clienti *
   V.le Stelvio, 2 – 20159 Milano
  Apertura al pubblico: dal lunedì al venerdì dalle 9.00 alle 12.30 e dalle 13.30 alle 16.00
  Telefono: 02.48.03.83.45/46
  Fax: 02.48.03.82.70
  E-mail firstname.lastname@example.com


How does Planck's curve solve the ultraviolet catastrophe?

Question: I previously asked whether Planck's curve actually reaches zero, to which some of you answered that it only approaches it, which raises the question: doesn't this mean that a photon with extremely high frequency will have massive energy? I know that the intensity (number of photons) of such high-frequency photons is close to zero, but even if we have only one photon with high frequency the ultraviolet catastrophe would still be unresolved. So what is it I am missing?
Answer: The Planckian approaches zero fast enough: there can be some very high energy photons in a thermal distribution, but the probability of their presence drops fast; crucially, it drops faster than the energy rises.
Qualitatively, the $\sim e^{-h \nu / k_B T}$ factor in the distribution can be multiplied by any power of $\nu$ and still yield a finite integral.
Therefore, the energy carried by photons that have, say, frequencies higher than $N$ times $k_B T / h$ drops to zero as $N$ grows large.
You could find a $1 \mathrm{J}$ photon in the Sun's blackbody (where the average photon energy is of the order $10^{-19} \mathrm{J}$) but it is astronomically unlikely that you will, so on average the energy contribution by such photons is very small.
I've tried to give an intuitive answer; if you want a more formal one try to integrate the Planckian yourself to find the energy carried in a specific frequency band!
Comment: Caveat: the calculus skills required to "integrate the Planckian yourself" are not insignificant.
Comment: I agree! If OP wants to go down that route perhaps they'd benefit by taking the high-energy limit initially so that the calculation is easier, since they are interested in that contribution anyway...
Comment: @JacopoTissino you know how the OP said intensity is "number of photons"? How? I would have asked OP myself but his bio says it was last seen a year ago whereas u were seen 1 week ago.
Answer: Planck's Law relates the spectral radiance of the body $ B ( \nu, T ) $ to the frequency of the photon by $$B ( \nu, T ) = \frac{2 h \nu^2}{c^2} \frac{1}{e^{ h \nu/ k_B T} -1} . $$
It replaced the Rayliegh-Jeans Law (first put forward by Lord Rayleigh but the derivation was subsequently improved by Sir James Jeans) which gave $$B ( \nu, T ) = \frac{2 \nu^2 k_B T}{c^2} $$
which can be written as $$ \frac{2 \nu^2}{c^2} \times k_B T$$ and interpreted as $$ \# \mbox{ available states} \times \mbox{ energy of each state}. $$
Similarly Planck's Law can be written as
$$ \frac{2 \nu^2}{c^2} \times h \nu \times \frac{1}{e^{h \nu/k_B T} - 1}$$ which is now interpreted as
$$ \# \mbox{ available states} \times \mbox{ energy of each state} \times \mbox{ probability of state being occupied}.$$
Rayliegh-Jeans uses equipartition of energy to assume that each available state has the same probability of being occupied (namely unity) while Planck has the factor $$\frac{1}{e^{h \nu/k_B T} - 1}$$ which is the result for boson's (that photons are an example of).
It follows that there are two main differences between Rayliegh-Jeans and Planck: (i) the energy of each allowed state changes from $k_B T$ to $h \nu$, (ii) though the density of states increases with $\nu$, the higher the frequencies are less likely to be occupied.
Answer: You are missing the Stefan-Boltzmannn law, which states that the total energy radiated by a perfect black body is $$P = \sigma T^4\,.$$ This also means that the total energy emitted is converging.
Answer: The Planck curve is actually about probabilities.
You can always cut a very small interval of time and pretend that photons emitted in that interval don't fit the curve (and they will indeed not fit - they are a discrete events and the curve is pretty much analtytical).
On the other hand, if you wait long enough in order to get some very high energy photon, you will (highly likely) build a great deal of statistics over the photons near the maximum, so you won't get UV catastrophe.


Internet without space

Question: Suppose mankind never developed spaceflight, which precludes any form of space-based stations or satellites. How could a single global Internet be achievable as we know it today? What technologies would need to be developed/utilized to allow the Internet to be available, reliable, and maintainable across oceans, mountains, and other terrain?
Comment: Everyone knows that the internet is a [series of tubes](http://en.wikipedia.org/wiki/Series_of_tubes), no satellites involved.
Comment: In a way, that's true, since wires are just cylinders of arbitrary height.
Answer: Submarine communications cable can cross oceans just fine, no space technology necessary. Started in 1853.
Mountains and other terrains is just hassle. Cable is easy to lay and easier to repair - but repairing even sea cable is possible, see link above.
Pipeline is harder but also possible overland, over or around any terrain.
Satellite in geostationary orbit is 50K km away. Round-trip is 100K km. More than twice than distance around the world.
Few cool factoids:

99% of international data is transmitted by submarine cables, which are as thin as Magic marker pen;
and are sometimes bitten by sharks, and routinely tapped (in international waters) by spy agencies.
undersea cables (technology older than telephone) are faster and cheaper than satellites.
easiest way to wage cyber warfare is in scuba gear using wire cutters.
almost 10% of cables are "spare" - laid but not used.
Comment: Not only that, but they provide much lower latency and are not affected by weather.  The only common uses of satellites for data transmission are satellite TV and radio, and communication in remote areas.
Comment: Why would they? They prowide superior bandwidth.
Comment: Yup, in my day job I get daily emails about degraded service of Inmarsat and others. :-)
Comment: Interesting. I hadn't realized the submarine cables were still in use. I assumed they were replaced by satellite technology.

Internet without space


When filing jointly, does it matter whose bank account is used to pay?

Question: If both the wife and husband filed jointly, does it matter whose account we use to pay taxes due?
Comment: On a typical US income tax Return, **most of the tax due** has already been sent to the IRS via tax withholding, and these amounts are shown on the W2 form(s) that the spouses **receive** from their employers. These amounts need to be added up and the total reported on the tax return. If any additional amount is due, a check for this amount needs to be sent (usually to a different address than the one that receives your tax return). The IRS doesn't care _which_ bank account this check is drawn on, as long as it is honored. If one spouse refuses to pay, the IRS will collect the entire amount...
Comment: from the other spouse: no halfsies there. On a joint return, each spouse is jointly and severally (meaning individually) liable for the _entire_ amount of unpaid taxes. You cannot claim that you paid your half of the amount due and tell the IRS to collect the other half from your spouse.
Comment: @teja - you've asked a series of very basic questions. Do you mind updating your profile with a bit of information, location, marital  status , for example, so we can better help you?
Comment: Thank you when it is necessary sure I don't hesitate to ask you.
Comment: Any how I am single not married
Answer: Whichever account you put on your filing; it doesn't really matter. I file the taxes for my wife and I (married - joint), and I pay the taxes from my checking account because I choose to, but I could use my wife's account. When filing jointly, the IRS doesn't really care which account the money comes from, or goes back into. As with you other question: Question about married couple filing jointly  I think you need to get a better understanding of how to file taxes in general. If you use a tool like TurboTax or HR Block or Tax Slayer (or one of the others), they will basically walk you through it.
One item that may come up is that you may both need to be listed on the account in order to receive a refund. Payment to the IRS doesn't matter, but I believe when receiving funds, filing jointly, the receiving account needs both names on it.
Comment: @teja , you're welcome. If this answer meets your needs, please mark it as the accepted answer.
Comment: @teja It looks like you've already accepted it, but maybe someone did it on your behalf (didn't know that was possible). When you want to mark an answer as accepted, you can hit the check-mark icon under the up/down voting buttons.


9 speed chain on 8 speed derailers to reduce chain rub

Question: I'm getting some chain rub on the hardest gear in the front and 2 hardest gears in the back where the chain hits the front derailer cage outer side.  When I spin the pedal it seems like the chain is not moving straight e.g. in certain points of the revolution the chain comes closer to the front derailer cage to the point of barely touching.  I have tried adjusting the derailer at the LBS but still have this issue of rubbing the derailer cage.  Can I go for a 9 speed chain on my 8 speed Claris since the chain is thinner and reduce this issue?
Comment: I'm going to say "probably" as a direct answer to your question.  But I would also suggest you shouldn't have to be asking it.  If your drive train is properly setup and aligned there should be no rub, maybe back to the LBS for another crack at it.  Would also think that the difference in width between an 8 and 9 speed to be so nominal unlikely there being any real improvement.
Answer:
When I spin the pedal it seems like the chain is not moving straight e.g. in certain points of the revolution the chain comes closer to the front derailer cage to the point of barely touching.

You have to fix that first. The front rings are bent and need to be trued so that they track straight. The lateral motion from a bent ring is more significant than the differences in chain width.
No matter how true you have your front rings, under heavy pedaling, like during hill climbing, there is frame flex, and derailleur rub may show up which is absent under light pedaling. If you lower your expectations to accept this, you will have an easier time.
Make sure you understand the limit screws. Front and rear derailleurs have them. The limit being set too tight on the front derailleur can promote rubbing. To loose a limit can result in the chain coming off. You have to fine tune it.
Check the rotation of the front derailleur around its mounting axis (the seat tube). The cage should be "aimed" toward the center sprockets of the cassette.   When the derailleur is rotated around the axis, because it has a curved profile to match the rings, under rotation, its aperture will appear slanted. That creates an offset between how it tracks the smaller and larger rings. Even if it looks well positioned, it's one more parameter at your disposal; it may be worth playing with to optimize it.
The height of the derailleur (up and down position on the seat tube) is another parameter to tweak that can interact with the rubbing issue.
I can personally attest that swapping a 6-7-8 KMC chain for a 8-9-10 speed SRAM on an 8-speed bike stopped front derailleur rub in the extreme positions. (This was in a bike where the rear derailleur is a Shimano Sora, which is rated for 9 speeds, so at least that component specifically "likes" the thinner chain.) The bike's rings were true, and everything was adjusted as well as could possibly be. In the end, the narrower chain made final difference in eliminating the remaining faint rub.
Comment: +1. Funnily enough on a new/old cheap bike I've just bought, I've got the same sort of problem - bad rhythmic chain rub in the big ring, and at a low torque part of the pedal stroke (right foot 12 o'clock to 1 o'clock).  The big ring is clearly bent if I look down while pedalling.  What's odd is that the plastic chainring guard is fine.  But that provides a point of reference.  It takes a clear road and a certain level of confidence to watch the chainring through a couple of strokes at a time, but if the ring is bent it should show up turning the pedals on a stand.
Comment: is it the rings or the say axis on the crank not inserted properly?  this can come from multiple culprite or is it the rings for sure?
Comment: @Lightsout Cranks on an entry-level 8 speed system typically don't have rings intended for replacement; they are permanently mounted to the crank. It's unlikely that out-of-true wobble is caused by some mounting problem; it's much more likely that the ring is bent. Bent rings can be bent back. It's not easy to get it perfect, but it can be improved a lot.
Comment: its a fsa tempo crank so I can buy a new ring but will run $40 at least
Answer: This might work, but it will likely be trading one problem for another.
9-speed chains do shift on 8-speed cassettes, but there tends to be noticeable lag to complete the shift compared to using the correct chain.
In front, the mismatch between chain width and cage inner width can cause issues where, for example, by the time the starting position of the inner cage is close enough to the chain to shift it smoothly from the small to large ring (or middle on a triple), the gap with the outer cage when in the high gear is too large, which can result in derailing or poor shifting in the other direction.
This issue is usually the result of a front derailleur that's either tweaked or needs re-positioning.
Comment: so would you say I need to adjust the limit screw outer and not the cable tension?
Comment: @Lightsout I wouldn't want to speculate without seeing it, but what I will say is that a very large portion of "unsolvable" front derailleur situations I see, where it rubs somewhere no matter what, are the result of it being mangled and in need of replacement.
Comment: @Lightsout I guess it could be both. The limit is a hard limit beyond which the FD can't go, no matter the cable tension. However, it needs a certain amount of tension so that it gets to the outer position. If you can manually move the FD so that it has enough free room but it doesn't go there through the STI, probably more tension, otherwise, give the limit screw a twist as well. That's the parameters, adjustment is always a bit of try & error. ;)
Answer: This feels like patching the symptom and not the root cause.
Yes you could use 9 speed chain on an 8 speed bike, but shifting will be a little sloppier.  You'll be moving from 7.1mm wide chain to 6.7mm wide chain, saving 0.4mm ( 1/64th of an inch or 15 thousandths of an inch) which is not a lot.  Personally I wouldn't bother.

Does your front derailleur support Trim?  That is more stop positions than your crank's total number of chainrings, and you an access them with smaller/shorter pushes of the shifter.
Another option is to try adusting the "low" limiter on the front derailleur to get a little more clearance.
Check the inside of the front derailleur cage too - it may have some dings and burrs which are artificially narrowing the entry.   Use a ruler to check if the cage is bent - it may simply need straightening.
Front derailleurs are fiddly and can still function even with minor damage like a bend.
Comment: If the current chain is actually a "6-7-8" speed chain, it could be about 7.3 mm wide.
Comment: Just to check my own understanding, but wouldn't the effective difference actually only be 0.2mm relative to the derailleur?  Assuming the chain is centered on the chain ring it's 0.2mm on each side +/- a little manufacturing tolerance
Comment: Personally I tend to accept that if a bike has to have chain rub, its better in the lowest gear combinations, so small chainring and big cog.  Mostly because I'm going slow  here, whereas if I'm in a top gear I want to go as fast as possible.


Can't connect to lan using hamachi with macbook and windows 10

Question: Trying to get a lan game going across 2 networks using hamachi. When I host the game (windows pc) and the macbook attempts to join using my hamachi ipv4 address, it is able to connect and load in before being kicked off within 15 seconds and while the computer is connected it is not able to do anything on my screen like move or look around. Now when I ping the mac's hamachi ipv4 address it comes back with around 80 latency, yet when the mac attempts to ping me using my hamachi ipv4 address it is not able to. Yet it is able to using my hamachi ipv6 address. I have tried attemping to connect using an ipv6 address in minecraft but that doesn't work.
I am able to connect to the mac's lan world using its hamachi ipv4 address no problems.
The 2 computers can ping each other and play on a lan game when on the same network no hamachi.
Thanks all
Comment: Please post your solution below as an answer to the question.
Answer: You can try typing this in your IP bar:
<code>[lancode]:[ip address of computer that is hosting]
</code>


How does InnoDB access disk?

Question: I know that block(multiple disk sectors) is the basic unit of data transfer for the virtual file system so, if NTFS uses 4 KB cluster size for files how does InnoDB access disk if it uses 8 KB page size?
Answer: Default InnoDB page size is 16K. Pages go into a larger 1MB data structure called an extent. MySQL allocates 4 extents at a time.
All of these are stored in one large file, so boundary issues have minimal effect on InnoDB.
You can read more about MySQL file space management.
Modern hard drives have read caches, and they read ahead, so contiguous sectors are already available when you ask for them without having to perform another seek.
Given enough working space (innodb_buffer_pool_size), InnoDB will store much of your indexes and data in memory, only waiting on disk for update transactions and commits.
According to MySQL documentation, it seems MySQL reads an extent (1MB) at a time from disk to the buffer pool, where it will access it a page at a time.
Comment: InnoDB only reads an extent at a time in read-ahead when it detects an linear scan. Most of the time it reads a page (16 KB with uncompressed tables) at a time. However the questioner is probably on a wrong premise, the OS is responsible for figuring out how to read the requested size read from the filesystem. MySQL/InnoDB requests 16 KB and doesn't care if the OS reads that from a single (large) page, 2 8 KB pages, 4 4 KB pages, etc... it has no control over that.
Comment: Hi Marcus, what I want to learn is if disk accesses are managed by file system how InnoDB make 16 Kb block i/o request to disk at a time?
Comment: According to [MySQL documentation](http://dev.mysql.com/doc/refman/5.5/en/innodb-performance-read_ahead.html), it seems MySQL reads an extent (1MB) at a time from disk to the buffer pool, where it will access it a page at a time.
Answer: The NTFS cluster size governs the granularity of allocation of disk space to files. InnoDB (and other application software) basically don't care what the file system's cluster size is.
When InnoDB reads or writes an 8K block, it just reads 8K.  When it allocates an 8K block, it allocates two 4K clusters.
That being said, if you're standing up a new file system for a MySQL server, it's a good idea to set the NTFS cluster size to match the block size.
Modern operating systems' physical disk IO can read and write large (46 k bytes or larger) streams of sequential data in single operations.
Comment: so u say that if InnoDB reads one page , file system makes two i/o request to disk?(4K + 4K=8K)

How does InnoDB access disk?


Smart contract gas costs

Question: What is the gas cost of deploying a Solidity contract, and how can I estimate it before deploying? Are there any strategies for minimizing deployment costs?
Answer: Most development environments, ie. local nets for testing you contracts come with some sort of gas measurement plug in. That will show you how much gas it costs to deploy your contracts. (ex. https://www.npmjs.com/package/hardhat-gas-reporter) You can use these alongside test scripts to measure gas of deployments and individual functions.
In terms of minimizing deploy costs, you can approach that mostly be having less code, or minimizing logic in your construction/initialization, but I would also note its much more important to focus on gas costs for users using your system foremost.
Deployments are usually a one time upfront cost, while any interactions users do will be an ongoing gas cost. I would always recommend optimizing the gas of typical interactions at the cost of deployment cost. Also, don't ever deploy to main-nets to test out contracts, since you can do all your testing on local nets or test nets for essentially free.

Smart contract gas costs


How to remove terrain in 3d?

Question: After the release of Minecraft I saw more and more rip offs of the game but some actually began to change it up a bit making the game have a organic look instead of the iconic blocky one that Minecraft does. If you'd like to look at the game that i'm referring to you can do so here. If you skip to around 50 seconds on the first video the steam page offers you can see the mining part that i'm wondering about.

I was wondering how this affect is achieved where they are able to remove part of the 3D object on collison with the players pick. I have heard about constructive solid geometry before and figured that could have been used but i'm not so sure.
Answer: It could be Constructive Solid Geometry indeed. But they said in the store page it is a voxel-based world (unless they lied of course). Which is basically pixels in 3D (or i could say cubes in the case of minecraft, and others).
In this case, it seems to me they smooth out those voxels to achieve that organic looks. Something like Castle Story which you can clearly see some are smoothen out, well not everything is like in Rising World, but you get my point.

How to remove terrain in 3d?