What do equalizer controls provide in decibels?

Question: What do equalizer controls provide in db? What do equalizers (like New Klark Teknik | High-Performance Dual-Channel 30-Band 1/3 Octave Analogue Graphic Equalizer, DN370 with Low/Hi Pass and Notch Filter) mean when they say +6 and -6 on the y axis? Is that 6db?
Answer: Yes. That means whatever frequency is being affected by the equalizer is being changed by the number of decibels indicated. Most of the time, a change of 3 to 6 decibels at a frequency is audible to most listeners. During mastering of recorded music, the mastering engineer may make important changes of .5 to 1.5 decibels or smaller.
Don't let any of the technical aspects distract you from basically making it sound good to your ears. If you are trying to make music sound good to others, you have to start with your own ears and learn how they are different from others' ears, and the best way is to get in there and start making changes and seeing how those changes sound.
Comment: The difference between a sound that causes physical pain and hearing damage and a sound that can't be heard at all is about 120 dB so there is not much point in any audio processor attempting to change something by 150 dB. Other signal processors (radio frequency or video signal) might benefit from changes that big but that is a huge power level difference. I don't think any real world audio device has a dynamic range of close 150 dB at all.
Comment: I know its indeed for my ears...Do they have 150db equalizers?
Comment: Never seen a 150dB tone control of any sort - it would be far too noisy.  If you want to dramatically cut or boost one narrow frequency you could look for a notch or bandpass filter, these can produce either a "wah" or phasing effect.  But extreme cases becomes unusable.  (Very high resonance filters often oscillate, and in any case they sound "weird".)
Comment: @ToddWilcox 24 bit digital audio has a dynamic range of around 144 dB, so it is not that uncommon.
Comment: By device I meant amplifier, speaker, signal processor, etc., as opposed to a medium or file format.  When you play back that digital audio, there's not much that can actually reproduce that dynamic range.


How do I get rid of two lockscreens?

Question: I have a Samsung Note 8. I took my phone to the store yesterday, and now I have a second lock screen with ads. I have gone through all of my apps that I dont regularly use, and have tried cleaning up junk files off of my phone, but nothing has worked. Does anyone know a way to get rid of this screen?
Answer: That lock screen (the one with ads) is usually from a cleaner app like clean master, 360, baidu etc there should be an On and Off switch inside the app or you can just uninstall the app
If you couldn't find it tell me the name of the app i tell you where it is

How do I get rid of two lockscreens?


What is the meaning of the expression "we have a ball game"?

Question: I've heard the phrase, "We gotta ball game". It could also be "We have a ball game". But I don't understand the meaning of "having a ball game". If anyone has heard this expression before, please help. I'm so very confused after guessing about this for a long time. The person who said it couldn't even tell me what he meant by this.
Comment: Since even the person who said this to OP couldn't explain what he meant, I'm afraid I'm duty-bound to vote to close as "too localised".
Comment: @Fumble: I think your vote to close is premature. People often repeat expressions they've heard without completely understanding their meaning.
Comment: @Callithumpian: Yes, but it seems very likely that in this case the *original* speaker not only didn't understand what he himself meant - he was quite probably misrepeating some version of *"We've got a whole new ball game"*. I find no instances in Google Books of *"We've got a ball game"* followed by, for example, *now, going* or any other word consistent with it not being a straightforward literal statement (as in *...to go to this afternoon*).
Comment: I agree with closing this; the answers illustrate how unclear the question is.
Answer: The prototypical phrase is "We've got ourselves a whole new ball game"; often meaning that the situation has so changed that one has a sporting chance of success in whatever the situation is.  Without the "whole new" part, it means that regardless of whether the situation has changed, one has a chance of success.
Idiomquest.com says, regarding "whole new ball game":

When the state of affairs change dramatically and presents new opportunities.

Edit: As others have mentioned, a phrase like we have a ball game may mean that a contest has developed, in a game that formerly looked like a walkover.  That might be what was meant by the person who said it, and of course is the sort of thing meant by the phrase a sporting chance in my answer above.
Looking at ngrams, it appears that the phrase new ball game is found a hundred times as frequently as any of got a ball game, us a ball game, or have a ball game; and looking at links from ngrams, the contest-has-developed sense is surprisingly rare, but of course does occur.
Comment: I agree this is a common idiom taken from sports jargon, but I don't believe this is the phrase referred to by the OP.
Comment: @FumbleFingers: See my [edit](http://english.stackexchange.com/a/54737/5822). Jwpat7 may be spot-on regarding _whole new ball game_. Unfortunately, that phrase has nothing to do with this particular question.
Comment: @Callithumpian, I've updated my answer to include that alternate possibility
Comment: Ok. I retracted my downvote. Though I have mixed feelings about having what I think is my correct interpretation of the question folded into someone else's answer. Since your answer was already chosen, I suppose it's all good.
Comment: @Callithumpian: Perhaps you'd be so good as to track down a few more instances where OP's "cut-down" version could be anything different to, say, a boxing commentator saying *"We've got a boxing match"* halfway through the fight. Which would simply mean that the earlier rounds weren't much of a contest, but would in no way imply that *"We've got a boxing match"* was something worthy of consideration here on ELU. Whereas jwpat7 is spot-on in pointing out that *"...whole new ball game"* is very much part of the general lexicon outside sports commentating.
Comment: @Callithumpian: You're right, and I was wrong. I can't reverse my vote to close unless it actually gets closed so I can vote to reopen. But I shall gladly upvote your answer as well as jwpat7's - yours because it covers the very specific usage, and his because it also covers the more common idiom which IMHO is likely to influence how far into general parlance this usage might get.
Comment: @Callithumpian, I too upvoted your answer, because it expresses a *possibility* of what was meant within question; but the person using the expression not knowing what he meant to say makes the point somewhat moot.
Comment: @FumbleFingers: I'll take you up on that offer to vote to reopen.
Comment: @jwpat7: That was what I thought when I first voted to close, but Callithumpian's dilligence in proving me wrong about the validity of the expression in the first place has made me doubt my own judgement in all things! I still think it's a highly localised question (because I'm UK, and it's obviously an (emerging?) US usage). But we answer questions where the OP doesn't know what some expression means, so why should it bother us if the person OP heard using it doesn't know either? Always providing it turns out to be a valid expression in the first place, obviously.
Answer: American sportscasters and sports fans will often say we have a ball game (often preceded by now or suddenly) when two sports teams seem equally matched or when the score of a game gets close, thus avoiding a blowout. A blowout could be seen as the opposite of a ball game in this sense. Another way of thinking about it is that having a ball game is synonymous with having a competitive matchup that is fair and interesting to watch.
This phrase has been borrowed from sports jargon and is commonly applied to other competitions, such as a close political race.
Edit:
At @Fumble's request, here's some more examples of the phrase used idiomatically:

from a real estate manual
from a novel
from another close election
Answer: When "we DON'T have a ball game," it suggests that the "match" is one-sided. "It's a ball game again," or "we've got a ball game" means that a recent event "suddenly" made a formerly lopsided game competitive.
Say one team is leading another in an American baseball game 5-0. In professional games, at least, that represents almost a sure win for the first team. But suppose the occurrence of the unlikely event that the trailing team hits a "grand slam" home run (for four points). Now, it's 5-4, not 5-0, and the formerly one-sided game is suddenly "competitive" (especially since the trailing team is still "at bat," and might add more runs).
Answer: Basically,

We have a ball game

is just a shortened form of:

We have a ball game to attend to.

Similary, "I have a meeting." is a shortened version of "I have a meeting to attend to".
People tend to shorten expressions for convenience.
Comment: Given that the OP said, "The person who said it couldn't even tell me what he meant by this." it's probably metaphorical, not this literal.


Algorithm question - check if there exists a path that touches A nodes exactly once and can revisit all other nodes

Question: I am having trouble with a problem where I am given an adjacency list and a list of the nodes that must be visited exactly once to connect two nodes. What is the most efficient way of doing this? This problem is the Hamiltonian Path problem except it is only certain nodes that have to obey this principle. Let me know if there is a name for this problem or if anyone has an idea of how to efficiently do this in maybe polynomial time.
Answer: As D.W. says, it is NP-hard, so we don't expect the problem to have a polynomial time algorithm, but it is FPT:
You can solve it in time $O(2^{|A|} n^5)$ which is polynomial if you consider $|A|$ small, e.g. $|A| = O(\log n)$. The factor $n^5$ can be improved.
Check out the (very accessible) paper by Shortest Cycle Through Specified Elements. Björklund, Husfeldt, and Taslaman, 2012.
This uses exponential space in $|A|$, but there are ways around that (e.g. using inclusion-exclusion methods by Nederlof).
Answer: You can't do it in polynomial time (unless P = NP), since it is as hard as the Hamiltonian path problem (consider the special case where you must visit all nodes).  One standard approach if you have to solve it in problem and the graph is small enough is to use a SAT solver.


Comparing difference between two subsets

Question: I have a large sample of 800 participants who completed a measure of relationship at 2 time points. The result of a paired-samples t-test indicates that there was no statistically significant difference between both time points. I then split the group into high risk and low risk subsets of participants likely to develop relationship problems over time. the analysis then indicated a statistically significant result for both subset! I do not think  that this is correct as I feel that one subset should be significant relative to the other?
am I right in thinking this or is there a better way of splitting the group into subsets rather than my approach of creating a dummy variable for each subset and selecting each subset and carrying out the paired samples t-test twice?
Answer:
I feel that one subset should be significant relative to the other?

From what you posted it doesn't sound like that's the comparison you were making but rather that you were comparing time t1 with time t2 in both subgroups. If that is the case I don't see any reason why the subgroups can't show a significant difference even if the overall population did not.
Assuming that your null hypothesis is that the mean difference between t1 and t2 is 0 it's not hard to imagine situations that might produce such a result: if the high-risk group has greater risk at t2 relative to t1 and the low-risk group has lower risk at t2 relative to t1, the overall group difference between measures at t1 and t2 could be close enough to 0 that you would not reject the null. If you are unsure about this you can always run some simulations with random data to see if this situation arises-- I threw one together in R using rnorm and found 10 such cases out of 10,000 trials.
The method for grouping your subsets seems fine to me, though it's possible that your criteria for subsetting the data could cause an issue (depending on how you categorize people as high- or low-risk).
Comment: Thank you very much for your insight. It just didn't make sense to me. the overall group performed worse at time 2, albeit non-statistically significant reduction in scores p = .88. The subset considered to be at high risk of developing relationship problems at time '1' (n = 31) reported an improvement in scores at time '2' p = <.001, r = 0.8, while the subset that were considered to be low risk at time '1' (n=245) reported a reduction in scores at time '2' p = .01, r = 0.2. From reading your post, i get it makes sense as one subset improved and the other did not.


Can qemu-img uncompress qcow2 file?

Question: We can use the -c option for qemu-img to compress the qcow2 file, e.g., here, but at the cost of uncompressing it while using. Suppose I am given a compressed qcow2 file, does qemu-img have any option or command to uncompress this qcow2 file? Thanks.
Answer: Yes, it can.
Use qemu-img convert with the -O raw option (or -O qcow2 without the -c compression option).  e.g.
qemu-img convert -f qcow2 -O raw input.qcow2 output.raw

or
qemu-img convert -f qcow2 -O qcow2 input.qcow2 output.qcow2

Comment: So, if I want to keep the qcow2 format, do I have to convert again from raw to qcow2? Is qemu-img able to uncompress directly from qcow2 to qcow2?
Comment: RE: "but at the cost of uncompressing it while using" - depending on the size and compression used, reading and uncompressing a compressed file is usually faster than just reading uncompressed data.   CPUs are fast and powerful, while disk I/O is slow (even on a PCI-e Gen 4 NVME drive).
Comment: You could use `-O qcow2` without the `-c` option if you wanted to retain the benefits of qcow2 (like snapshots).     Personally, I use either compressed qcow2 files or ZFS zvols (with compression enabled).....and use `qemu-img` to convert between them if I need to.

Can qemu-img uncompress qcow2 file?


How to use" everyone" or "everybody" in a negative sentence with verb "be"?

Question: When checking if all the students are present in a class, may the teacher ask "Is everybody/everyone here today?" or "Is everyone/everybody present today?"
And if not so, must the students reply "No, everyone/everybody IS NOT here today." or "No, NOT everybody/everyone IS here/present today."?
Answer: "everybody" and "everyone" are equivalent, see these links:
https://www.merriam-webster.com/dictionary/everyone
https://www.merriam-webster.com/dictionary/everybody
The normal way to answer in the negative is:

No, not everybody/everyone is here/present today.

As you can verify with google, "everybody is not here" is much less common than "not everybody is here".
I can see there might be a few cases where you would say "everybody is not here".  It's more emphatic and could be spoken with hostility.  For example, if half the class is obviously missing, someone could say:

Could we get started, since everybody is here?
No, everybody is NOT here.  Don't start yet!
Comment: Can you confirm that "No miss, NOT everyone is here today" in the mouth of students as an answer to their teacher taking the attendance does sound quite natural? To me "No miss, everyone IS NOT here today" sounds more natural. What do you think?
Comment: It would be more like "No miss, not EVERYONE is here today."  I think that sounds more natural than "everyone is not here".  But the more likely way to answer the question would "no, so-and-so isn't here" or "no, some people aren't here yet".
Answer: Everyone and Everybody both mean "all the people", the question is what group contains the people.
Everybody is "all the people" in the world.
Everyone is "all the people" in a smaller group.  This is usually, the people in an already mentioned group, or if no group is mentioned, all the people in the group being addressed.
Many people, even native English speakers, accidentally use "everybody" when they mean "everyone", so be prepared to use other clues to figure out if they really meant "everyone".
When responding, try to use the word "no" only once, and place it close to the verb.  This will have the least chance of being misunderstood.

Everyone is not here today.

Is the best answer

Everybody is not here today.

Is an acceptable way to answer "Is everybody here?"  Even if it not the correct use of "Everybody", since the person asking used the wrong word, there will be no misunderstanding in the answer, as you are matching your mistake to theirs.


How to understand multiplicity $N_{ij}^{k}$ in general fusion rules in conformal field theories?

Question: I cannot quite understand the fusion rules in conformal field theories:
\begin{eqnarray}
\phi_i\times\phi_j=N_{ij}^{k}\phi_k,
\end{eqnarray}
where the coefficient $N_{ij}^{k}$ according to textbooks can take general nonnegative integers. I cannot quite understand why that $N_{ij}^{k}$ is larger than 1 is meaningful. Since $N_{ij}^{k}$ is nonzero as long as
\begin{eqnarray}
\langle\phi_k\phi_i\phi_j\rangle\neq0,
\end{eqnarray}
the specific value $N_{ij}^{k}$ seems meaningless.
Comment: You should provide additional  context on what the $\phi_k$ are, what fusion rules are etc so that your question is a little more self-contained.
Comment: Hi Smart Yao: Is your real question why the fusion structure constants $N_{ij}^{k}$ (after appropriate normalization) is integer-valued?
Comment: @Qmechanic I was simply confused the mathematical meaning of larger-than-1 $N_{ij}^k$.
Answer: In general, the decomposition of a tensor product of two representation $\Gamma_1\otimes \Gamma_2$ (take them to be irreducible for simplicity) will result in a sum of irreducible representations
$$
\Gamma_1\otimes \Gamma_2 = \sum_k N_{12}^k \Gamma_k\, . \tag{1}
$$
Eq.(1) is called the Clebsch-Gordan series.  A particular irrep $\Gamma_k$ can generically occur more than once.  How many times an irrep occurs depends on $\Gamma_1$ and $\Gamma_2$.
As an example, suppose $\Gamma_1$ and $\Gamma_2$ are both the 2-dimensional $\{2,1\}$ irrep of $S_3$.  Then $\Gamma_1\otimes \Gamma_2$ is a 4-dimensional reducible representation which can, by elementary use of character orthogonality, be written as
$$
\{2,1\}\otimes\{2,1\}=\{3\}\oplus\{2,1\}\oplus\{1,1,1\} \tag{2}
$$
so in this specific example the various $N^{\{\lambda\}}_{\{2,1\}\{2,1\}}$s are all $1$.
Looking instead the coupling $\{3,1,1\}\otimes\{3,1,1\}$ of $S_5$ irreps, one finds
\begin{align}
\{3,1,1\}\otimes\{3,1,1\}& = \{5\}\oplus\{4,1\}\oplus 2\{3,2\}\oplus \{3,1,1\}\\
&\quad \oplus 2\{2^21\}\oplus\{21^3\}\oplus \{1^5\}\tag{3}
\end{align}
and you can see that $\{3,2\}$ and $\{2^2,1\}$ actually occur twice in the decomposition.
The same can occur for continuous groups.  Consider the tensor product $(1,1)\otimes(\sigma,\sigma)$ of $SU(3)$ irrep.  One can show using again elementary methods that
\begin{align}
(1,1)\otimes(\sigma,\sigma)&=(\sigma+1,\sigma+1)
\oplus 2(\sigma,\sigma)\\
&\quad \oplus (\sigma-1,\sigma-1)\oplus \hbox{other irreps}\, .
\tag{4}
\end{align}
In this specific example, the irrep $(\sigma,\sigma)$ occurs twice in the decomposition so this particular coefficient $N^{(\sigma,\sigma)}_{(1,1)(\sigma,\sigma)}=2$.
Some observations are in order.  If you think of decomposing the product of two irreps of $SU(2)$, then $N^J_{j_1,j_2}$ is either $0$ or $1$.  For other $SU(n)$, as illustrated in my second example, it may be that some coefficients are greater than $1$.  In general, $N_{ij}^k >1$ will occur when the representations $\Gamma_i$ and $\Gamma_j$ have weight multiplicities.  The problem of constructing the highest weight for irrep $k$ has multiple solutions due to the weight multiplicities.  (In $SU(n)$, both irreps must have weight multiplicities, but I'm not sure about other cases.)
In your specific examples, your fields carry a representation of some algebra.  Quoting this paper by J. Fuchs:

Fusion rule algebras are certain associative algebras over the complex numbers which arise in various areas of physics and mathematics, where they describe the possible couplings among three objects out of some given class.   As examples let me mention:
....

Truncated tensor products of unitary representations of quantum groups with deformation parameter a root of unity...

[the emphasis is mine] so one can think of the fusion rules are a generalized form of the Clebsch-Gordan series of Eq.(1), as opposed to Eqs.(2), (3) and(4) which are examples of the standard series.
Comment: Pretty nice explanation although a little (but trivial) suggestion on the missed square on l.h.s. of Eq. (2). I have a further question for my specific example of fusion rules in CFT. If $N_{ij}^k>1$, does it mean that it is necessary to have at least $N_{ij}^k$ different primary fields with the same weight $h_k$? In this sense, does it imply nondegeneracy of highest weights in minimal models?
Comment: @SmartYao I'm not an expert in CFT, but the game is counting highest weights.  From a representation theory perspective $N_{ij}^k>1$ means multiple distinct highest weights, irrespective of the degeneracy of weight $h_k$ (this weight might occur multiple times in other irreps where it is not dominant).  Thanks for the heads up on the typo, which is now fixed.
Comment: I now understand the source of this larger-than-one $N_{ij}^k$, but I was wrong in my last comment in that $N_{ij}^k\leq1$ does not mean the nondegeneracy in highest weight.


Does USGS Landsat 8 Collection 2 Tier 1 TOA Reflectance need cloud mask before NDVI computation

Question: For computing the NDVI I want to use USGS Landsat 8 Collection 2 Tier 1 TOA Reflectance LANDSAT/LC08/C02/T1_TOA does it need cloud masking or any other form of ''cleaning'' before I can use it?
Answer: The Landsat 8 Collection 2 encompasses Level-1 (top of atmosphere reflectance) and Level-2 (atmospherically corrected surface reflectance) products. Since Landsat 8 Collection 2 level-2 correspond to surface reflectance and;

corrected for the temporally, spatially and spectrally varying
scattering and absorbing effects of atmospheric gases, aerosols, and
water vapor

it should be used to generate NDVI.
However, you need to apply scaling factor i.e., 0.0000275 + -0.2 for Level-2 before calculating NDVI. You should mask pixels which are contaminated by clouds and shadows as well.
Here, I would recommend a worth reading article "A survival guide to Landsat preprocessing" for further enlightenment.
More information about Landsat Collection 2 Level-2 Science Products can be accessed from here.
Comment: Are you sure about the scaling factor for `LANDSAT/LC08/C02/T1_TOA` on GEE? I am new to all of this but here are two observations: 1) the GEE guide [here](https://developers.google.com/earth-engine/tutorials/tutorial_api_06) shows how to calculate NDVI and does not use any scaling. Just `image.normalizedDifference(['B5', 'B4']).rename('NDVI')` where `image` is from the `LANDSAT/LC08/C02/T1_TOA` collection.  2) Before scaling, values should be between 1-65455 but I see values such as 0.2 for B5 in my quick check.
Comment: Please see the link added in answer for more information
Answer: Yes.  There are examples in the code editor for doing cloud and shadow masking.


Synchronize SharePoint 2013 Calender with Microsoft Exchange Server

Question: How to do two-way Synchronization between SharePoint 2013 Calender with Microsoft Exchange Server?
Answer: You can try also some 3-rd party tools for it. Ex. from VirtoSoftware - http://www.virtosoftware.com/sharepoint/exchange-group-calendar-web-part
or from Amrein - http://www.amrein.com/apps/page.asp?Q=5778
Using these web parts you'll be able to synchronize your Exchange Calendar and SharePoint Calendar. And this configuring will work in two-ways. You can add multiple exchange calendars into one view if needed.
Hope it will help you!
Comment: Would you please provide some explanation on your answer. Link only answers are not that good to read for other reader, as sometime links tend to break.
Answer: Integrate an Exchange calendar with your SharePoint site by installing the Outlook Web App, My Calendar Web Part. With the My Calendar Web Part, you can maintain your Exchange calendar from OWA or Outlook, and calendar events will be synced to the SharePoint page where you install the Web Part. This feature is useful for sharing office hours, room schedules, resource bookings for equipment, events, etc.

Go to the SharePoint site, and browse to the page where you will
integrate the calendar.
Click Page and Edit Page.
Click Add a Web Part. Click the Outlook Web App category.
Click the My Calendar Web Part, and click Add.
Click "Open the tool pane" on the My Calendar Web Part.
Enter https://spowa.uark.edu/owa/ in the Mail server address field.
Enter the UARK email address for the account's Exchange calendar.
Click OK.

https://techarticles.uark.edu/sharepoint/sharepoint_integrate_with_exchange_calendar/
Below link is for 2010 but you can try to amend the 2013 MyCalendar webpart.
http://msdn.microsoft.com/en-us/library/office/hh528520(v=office.14).aspx
Comment: Thanks.There is no proper guides or documents in MSDN for the Integration of Exchange-SharePoint 2013 Calendars.My Calender Web Part is Not available in SharePoint 2013.Instead of that,It gives only the "Outlook Web Access(OWA)" through the IFrame(Page view Controller).Does SharePoint 2013 provide any methods to integrate with MS Exchange through the C# Code/Webpart rather Than just a Webview? Is there any documents/guide from MSDN,That provides a clear guide to Integrate SharePoint  2013 Calendar with Exchange Calendar?


losing weight versus getting lighter bike

Question: Which would boost riding performance more: losing weight, or keeping the weight but a lighter bike?  I know that a good bike is not just about weight, so assume that the new bike purely weighs less and not has better mechanical parts.
Comment: Good luck shaving 20 pounds/10 kg from a 25-pound/12 kg bike...
Comment: This is so far into the realm of the hypothetical that no answer is meaningful. This also seems to assume that you could lose weight from your body without any changes to your fitness. It's just not realistic.
Comment: Depends on the individual.
Comment: "Why not both ?"   Once the bike hits 6.8 kg (the UCI minimum) then its as low as it can go ad still compete in UCI races.
Comment: Your assumption doesn't hold in practice.  Yes, it's possible to save some weight with a lighter frame keeping all else equal, but there's quite a bit to be saved by using lighter components, which of course are priced higher.  Whether these are "better" than heavier ones depends on your use case.  If extra weight would guarantee losing a race, then going as light as will survive that race is a good strategy.  It's not so good if you want to ride long distances in variable weather and things wear out before you finish the ride
Comment: @Criggie I don't think I've *ever* seen a bike weighed at any UCI event.  I seem to remember that any weighing must happen before the event, and the "penalty" for an underweight bike is just to get a bike that's not underweight.
Comment: @AndrewHenle they absolutely do - normally at the end of the race, the bike is grabbed straight off the finish line and weighed.  Perhaps more for the top-end races, and less in lower grades.
Comment: Woot looks like my question got on the hot network question list again.
Comment: It depends on how much the extra weight of the rider did cost, (expensive) restaurant-visits-wise. ;-)
Comment: For me, it is obvious I should lose some weight.  I could also spend a lot of money and get a lighter bike.  I could just ditch my panier bag and heavy chain lock and instantly cut a big chunk of weight.  For a high performance cyclists with approximately 0% body fat and a bike made from super light weight unobtanium, there is not much weight to lose.
Answer: If you want to get faster, train better.
On flat terrain, weight is virtually irrelevant for your speed. It is only relevant when you accelerate or brake, but not while you are riding at speed. So stop worrying about weight, but focus on your power output and/or the efficiency of your bike.
On hilly terrain, weight is indeed important. But so is muscle mass. And building muscle mass will both help you get up the hills faster, and help you in loosing weight. The important part is doing the exercise, the weight loss is just a bonus, imho.
Of course, if you want to get competitive in even slightly hilly terrain, you absolutely need to keep your weight low (doesn't really matter if it's bike mass or fat) so that you only carry as much weight up the hills as absolutely necessary. In this case, low weight is simply necessary to turn your body's power output into the highest climbing speed possible. But even top athletes need their muscle mass. And believe it or not, they do a lot of training...
Comment: And when you've done the hard work of carting that mass up the hill, you get the added benefit of a higher "terminal" speed on the downhill.    Which means downhills are faster and quicker and you can pass the lighter riders as they waft down the far side.
Answer: The exact wording of relevant bits of the question is:

losing weight or getting the same weight less in a lighter bike ... assuming that the new bike purely weighs less and not better mechanical parts.

If we take the question's wording literally, then if you lose a certain amount of weight without affecting your physical fitness, that should be equivalent to losing the same amount of mass from the bicycle if all else is held equal. The issue is that holding all else equal is difficult.
The issue with this is that if you're overweight and you lose weight cycling, your physical fitness most likely goes up. So, not all else is equal.
Additionally, while it's likely this situation doesn't apply to you, it's worth stating that if you are already fairly lean and you lose weight, you can reduce your physical fitness. If you're interested in this side of the problem, Google relative energy deficiency in sport (RED-S). This syndrome can affect both men and women, although women face additional social pressure regarding weight and they may affect their reproductive health long term (more so than men) if they get RED-S. This is receiving increasing amount of attention in professional cycling, and I suspect all sports that have weight classes or involve some sort of power vs weight test face this issue.
On the side of the bicycle, we don't know what your baseline bicycle is. If you are going from a city hybrid to even an entry-level serious drop bar bike, chances are the bike will be lighter and noticeably faster. In that comparison, most gains will probably come from better tires and a lower and more aerodynamic position. For mountain bikes, the gains from a low end to a nice bike might be even greater due to improvements in suspension (although your skill may limit your performance). If your baseline bicycle was a good-quality performance bike, then it's now well documented that improvements in aerodynamics, drivetrain friction, and rolling resistance are far more powerful in most situations than weight losses. Strictly speaking, it's probably more cost-effective to improve your own physical fitness than to improve your bicycle. Also, if you get parts that are much too light, you can sacrifice durability, although that tends to happen at much higher price points.
Last, there are also non-objective considerations. Lighter bikes can feel a lot nicer to ride than heavier ones. They often feel faster and pleasant to ride, even if they are not actually much faster. If that feeling would get you to ride more, it is something worth considering.
Answer: As asked, only dealing with weight change, not considering other factors that make a bike rider faster.
For highly trained cyclists, losing weight means losing muscle mass, presumably from muscles that power the bicycle. For these people, losing weight from the bike is the preferred option.
For most riders, losing weight is not only possible, but if done to a plan suitable for someone who care about performance, will also increase muscle mass.  For these riders, its probably cheaper and more effective as a performance gain to lose weight.
For most of us, putting down cash on a lighter bike has the dual effect of not only providing a lighter total weight. Not only the lighter bike, the weight loss in the wallet cannot be ignored, as even when the wallet is left at home, there is a psychological effect that is carried on the bike.
However riding is far more complex than power to weight. Weight has a linear effect when accelerating and climbing and descending, but aerodynamics operates to a square law of speed. Above even a moderate speed, drag become more important than weight. A super light rider has lower power to go with the low weight. This is great on hills where power to weight is what counts. On the flat, especially head winds,  drag quickly becomes the limiting factor, and a more powerful rider, typically bigger, has a much higher power to drag ratio.
Of course, everyone likes to worry about weight and power, very easy beans to count these days and can be given hard, quantified numbers (My bikes 5.3kg, I am 75.7kg and I produce 423.79W). Drag on the other hand is ignored in most discussions involving cycling beyond "less is better, here is how to get less", as it's practically impossible (i.e. insanely expensive) to quantify and come up with hard numbers.   (Every article on any piece of kit gives weight to the microgram, none give a number for drag.)
Comment: Is that your FTP? Jeez.
Comment: Hard numbers are possible today, but I wonder how you can say you produce (present simple, so I assume repeatedly) a specific power with 0.002% precision.
Comment: Clarification - the numbers are completely made up, sorry I did not make that clear.
Comment: "Every article on any piece of kit gives weight to the microgram" Unfortunately this is not true. Plenty of manufacturers don't state a weight at all (or only for one size) or with huge inaccuracy. Reviews are sometimes slightly better in this regard. But I agree that aerodynamics is even less quantified (except for some wheelsets).
Comment: I measure drag from various sources (aero, rolling, acceleration, and mass, but not drive train losses). It's not impossible and it needn't be insanely expensive. It does take time and care.
Comment: 5.3kg?! I'm used to riding  a bike that weighs twice as much as my companions', but by the time I've strapped on my pump and tool kit it's 4x yours
Comment: @R.Chung I've read your methods, and keep considering having a try, but assessing many potential configurations would take quite a lot of work (admittedly in my case it would be about luggage options for fast bikepacking, so far more permutations than a race setup)
Answer: When some years ago I decided to start doing multi-weeks cycling vacation, I asked myself how to make sure I could manage riding about 100 km a day, several days in a row.
Since I already had a light bike for touring (aluminum frame and carbon fork, 7-8 kg), what I could save with a lighter bike which was going to be loaded with panniers was way less than what I could save by losing some weight.
So I paid more attention to my eating, and managed to drop about 12 kg over the winter. Since those kg were mostly fat, it didn't negatively affect my performance, it just allowed me to wear cycling gear and slim fit shirts without being afraid of ripping them open :D.
Unless you are riding a fence with wheels, I think there is more margin of maneuver on your weight than on your bike.
Answer: That depends! Alot of people who use the gym seem to know that muscle weighs more than fat. It's a fact that many good riders who are heavier put out more power than the lighter riders, but the power to weight ratio may work against vs a lighter, less powerful rider. The power rider may win the sprint, the lighter rider may fly up the hills with less effort.
Back in the real world, there are a significant proportion of people for whom buying a bike at 2kg lighter than the old one is "easier" than losing 2kg of body weight, which all helps with acceleration and going uphill.
Hopefully someone will give you a better answer!
Answer: When riding uphill it's simple: Speed is all about power output vs. total weight. It doesn't matter where the weight comes from. If you can reduce weight without decreasing power output your speed will improve.
In flat-ish terrain or during descents drag is more important than weight. Time trial bikes and wheels are usually noticeably heavier than lightweight road bikes but have much better aerodynamics and are therefore faster on flat terrain. The seating position is also often uncomfortable to the point of reducing power output but the gains in drag reduction are worth it. For the rider it mostly boils down to power output vs. frontal area.


27 bit parallel Bus @65MHz: Use 3.3V or 1.8V?

Question: I've a LVDS transmitter (SN75LVDS83B) connected to the GPIO bank 0 (as DPI24) of a raspberry pi compute module 3. The pixeclock is 65MHz, the 27 parallel lines are 3 x 8 bit RGB + Hsync + Vsync + DE. The length of the lines is approx. 80mm.
Now I have the choice to power the GPIO bank 0 and the LVDS receiver with 1.8V or 3.3V. Both works and I ask myself what would be the better option. My pro/cons:

3.3V pro: Higher signal to noise ration
3.3V contra: Higher electromagnetic emission and energy consumtions
1.8V: The above inverted: lower signal to noise ration but less emissions and power consumption.

Are these assumptions correct and are there other reasons to prefer 3.3V or 1.8V (both are present so there aren't additional expenses for a second voltage)
Comment: Leave yourself with both options open and test to decide the best configuration.
Answer: As all things are equal in your description (ICs available and operate  in both voltages), the 1.8 V solution will be the better choice. Your reasons listed are correct and signal rise/fall times should be better and will be no worse.
The 65 MHz signals should not be corrupted on their 80 mm trip to your PCB if you use a good, standard cabling/grounding scheme (outline more in your question and I can expand this answer).


Can I use one number on two different phone(Device) on Whatsapp?

Question: I just want to know if it is possible to have on two phones the same whatsapp messages.
Comment: normally its not possible i think
Answer: The short answer: you can't do it using the native app, but there is a web interface that will work on Chrome, Firefox,  Opera and most other browsers  in desktop mode (i.e. "request desktop site" or "user agent: desktop").
Whatsapp allows only one device to pull your messages from their servers. You can make the app think you only have one device by changing the MAC address and some other files using root access, but that doesn't mean it will work.
Whatsapp messages are stored only temporarily on the whatsapp servers. This means thay when device A downloads those messages, device B can no longer see them. This means that, in order to keep your messages synchronized, you will need to constantly sync your messages using tools with root access. This is not very usable to most people.
The easiest solution would be to use the app on device A and the web interface, (web.whatsapp.com), on device B. To make this work on an Android device you need to make it request the desktop site. There you can scan a QR code into your first device by opening the menu and selecting "whatsapp web". Point your camera at the QR code and you can use Chrome to send and receive whatsapp messages.  This requires the device with the official app to be on and connected to the Internet.
Comment: Most up-to-date browsers work with WhatsApp Web. I know for sure that Chrome and Firefox work. The  latest Opera browser works as well, but I couldn't get Opera Mini to work. Those are all the browsers I use on a daily basis, other browsers should work as well as long as you can request the desktop version of the site.
Comment: Does this only work on chrome? Have you tried other browsers?
Comment: Okay thanks. Please correct the "constantly" spelling in your answer.
Comment: I updates the answer, thank you for notifying me. I'm not a native English speaker so feel free to edit my answer if you see more spelling/grammatical errors.
Answer: Once your phone number is verified by WhatApp, whatapp will just keep sending the messages to your internet connected device from where you sent the message for verification. If you take a titanium backup of whatsapp and restore it to any device, it will start accepting messages from whatsapp.i have recieved messages on either devices and it worked if the devices are synced off line. I used one at a time. But never both of them together and  think doing so will require re-verification of phone number. For receiving and sending messages and identifying your device whatsapp doesn't check phone number of device but the verification saved in your device.
Answer:
is it possible to have on two phones the same whatsapp messages?

No
Whatsapp messages are stored locally on the phone, with periodic encrypted backups to sdcard. Its unclear that the messages are stored on the server once they are delivered. And even if they are, whatsapp doesn't provide a sync feature to sync messages to multiple devices as of now.
On a 1st device, when a message arrives, it gets stored locally on device and backed up to sdcard as a file. Say on the 2nd device (whatsapp cannot be used simultaneously actually), when a message arrives, same thing happens and u have a backup of file. So, you have got two files from each device, but you cannot restore messages from two backup files. And restoring messages is an option only when adding an account, not when using the app normally.
So, as of now, you cannot have duplicate message copies in both phones.

Can I use one number on two different phone(Device) on Whatsapp?

No, not atleast simultaneously. Ofcourse excluding Whatsapp Web (see below).
Say you have logged in to whatsapp on 1st device. Then, say, you login to 2nd device and complete the verification process. Now when you open whatsapp on 1st device, it complains about whatsapp logged in from elsewhere and asks you to reverify. And if you reverify, the 2nd device gets unlinked, and it continues.

Whatsapp Web

This can be used only if the browser and whatsapp linked device is side-by-side and the device has active data connection enabled. You need to scan the qr code displayed in the web browser from whatsapp on your phone (actually only this verification part requires devices side-by-side). Then you can use web version till the device looses data connection. The web version is a blue print from the device. You will see all the contacts and messages on the device in the web version. But considering qr scanning and always on data on mobile, the web version is far from multi-device usage.


How to write test case for catch in following method?i want to cover catch block in code coverage

Question: <code>@RemoteAction
public static  List<Account> GetAccountOwnerEmail(String AccountId) {
    List<Account> lstAccount = new List<Account>();
    String [] conFields = new string[]{'Email'};
    if ( !se.isFieldAccessible('Contact',conFields,FLS_Security.FLSType.ISACCESS) ) {
        throw new MyCustomeException ('You do not have sufficient privilege to perform this operation for Contact, Please contact to system admin');
    }
    try {
        String queryString ='Select Id ,(Select Id,email from contacts) from Account where Id= :AccountId';
        //return(database.Query(queryString));
        lstAccount = database.Query(queryString);
        return lstAccount;
    } catch ( Exception e ) {
        ErrorLog.createErrorRecord(e.getStackTraceString(),e.getMessage(),e.getTypeName());
        throw e;
    }
}
</code>
Comment: Your question appears to be asking for other people to write code for you. SFSE is a Q&A forum where we look to help each other by asking and answering questions about real problems or errors with our code. Posting requests to write code for you will get closed. If you post what you've written so far and where you're stuck, I'm confident you'll find plenty of people willing to assist you
Comment: As told by @ninja.hk try by passing some junk value to parameter accountId like 123 it will give you error "ERROR at Row:1:Column:30 invalid ID field: 123" and execute catch block.
Answer: The try block contains only a string assignment statement and a query statement. The string created is straightforward, so no chance of getting an exception there.
Another statement is Database.query() which may throw an exception if the query is wrong but as the query string is hardcoded there, you cannot get a QueryException as well.
So to force an exception you will have to change the code a little bit. Instead of directly using the variable AccountId in query, first create a local variable of type Id in try block, assign the value of AccountId to it and use this variable in query.
Here if the value of AccountId is not actually an Id, a StringException will be thrown saying Invalid Id while assigning it's value to variable with Id type.


Suggestions for removing a crankset from 1980s-era bike

Question: I've removed a number of cranks from bikes built in the mid 1990s and later with my inexpensive crank-pulling tool, but I have been unable to remove the drive-side crank from a 1980s-era bicycle. The NDS came off with a little coaxing. No luck on the drive side. The steel of the BB spindle is harder than the metal of the crank pulling tool and is chewing it up.  I'm open to suggestions. Are vintage versions of these tools made of stronger metal?
Answer: You can get these tools with a rotating contact part. The park tool does this amongst others. You have to be willing to invest a little more but the tool is more capable.

You could try supplying a small disc of hard metal at the contact point if you can find anything of a useful size, it may or may not help with your particular tool.
If you are removing the crank in order to dispose of it, there are some alternatives. Please clarify whether that's the case.
__
Destructive option:
Let us imagine that you stick with your old tool or the threads in the crank get destroyed. You still need to remove the crank and it's a sacrificial part in this case.
If the crank is aluminium/alloy, it's easy enough to cut accross the hole where the crank bolt goes, as deeply as possible and with a view to being easily able to smack parts of the crankset with a heavy hammer. You can't cut through the bottom bracket axle because it is made from a metal that is harder than your hacksaw blade, so don't worry about that. Protect the frame where necessary and support it approprately from the other side on the floor to take up the shock. You can either beat the crankset gently, expanding your cut, perhaps with a wide/thick screwdriver blade as a chisel, and alternately knocking it offwards until you have success or you can give it hell and beat it hard until it breaks where you have weakened it with the cut. This technique doesn't work for steel cranks but it's very theraputic and gives your workshop a priceless "no shits given" atmosphere.
Comment: Park extractor +  WD40 +  front wheel off +  right crank touching the floor + adjustable wrench on the extractor + whacks on the wrench with a rubber mallet = drive-side crank removed.
Comment: @Tim I know "no product recommendations*" but the park tool is one of the best crank pullers I've used and should last a long time. *Other brands are available.
Comment: Cutting and peeling will work for steel cranks too, but you'll need a proper cold chisel instead of just a screwdriver, and it's generally a good idea to cut two or more notches instead of just one.
Comment: Thanks. One of the Park tools is now on order. I wouldn't care if the crank got ruined in the process, but I'd like to spare the BB, at least for the time being.
Answer: Grease the end of the puller and threads. The idea is to remove as much friction as possible to maximize pulling force (although looking at your puller, you don't seem to have had a problem generating significant force).
Presuming aluminum cranks, as aluminum expands more than steel, heating the crank arm should help. Try a little heat first then add more. Take care not to over heat the frame, you want the heat focused on the aluminum of the crank.
A bit of percussion with the pressure from the tool can help. Best to have the crank arm supported underneath and hit the top, so minimal forces got though the BB and into the frame.
One very often success technique is loosen the retaining bolt (But leave it in place to stop the crank arm falling off) and go for a ride.  The crank arm will often loosen. If you do this, consider it a destructive technique for the crank arm, but the BB is saved.
Instead of hacksawing the crank, you can often drill a line of small holes. No need to go all the way though. The idea is you remove enough metal the remain amount will easily yield against the tool.  If you do this on diagonal corners of the square, you can then place a punch (or thin screw driver) into the holes and 'open' the crank with a hammer blow (Again, support underneath so the percussion does not get taken by the BB and frame )
Comment: Percussive persuasion: I've succeeded by taking the strain with a crank puller and then going round the hole in the crank arm tapping each side in turn using  a drift.  You might need to tighten the crank puller and repeat
Comment: @Perkins   Thanks for the tip. Does the anesthetic effect kick in before the explosion?
Comment: Thanks. If the new crank puller I have on order doesn't do the trick, I'll loosen the retaining bolt somewhat and spray it with WD40 and then ride it around as you've suggested and see how that goes.
Comment: @Tim  Kroil has much better penetration than WD40.  Starter fluid with upper cylinder lubricant also works, but evaporates quickly and you need to be careful because it's both a general anesthetic and explosive.
Comment: @Tim  It's generally made from diethyl ether.  It's not particularly potent as an anesthetic but if you, say, took a whiff from a jar of it it would probably knock you out briefly.  Use with plenty of ventilation.  As for explosiveness...  Well, it's what you use to start an engine when gasoline isn't volatile enough...
Answer: Instead of the internal puller, we used a universal external puller.
Something like this (I've no affiliation with Gedore, it was just the picture which came up first):

Source
Problem is getting one large enough to fit around the crank. Best case is when the gears can be removed, but with a crank that old, I doubt it.
We opened the retaining bolt just a tiny bit and left it in the BB and used that as the counterpart for the puller (as they likely don't fit into the hole of the crank). We didn't have any damaged threads after this, so the BB should be fine.
If you have to pull at the gears, they'll likely bend and make the crank unusable. Position it in a way so that it'll pull at the position of the mounting points of the gears.
Comment: Note that you can buy more versatile gear pullers that allow you to use 2 or 3 jaws. These often come in packs of several sizes. I bought some to remove a crank arm with stripped threads
Answer: If you're sacrificing the crank arm, use a ball joint fork. Only takes a couple of good licks with a hammer
Comment: Welcome to Bicycle Exchange. You might want to indicate that the person attempting this should protect the bottom bracket area of the frame to minimize damage there.


Are command tips in Texstudio editable

Question: Texstudio has the nice feature that when I hover the cursor over a command the correct syntax of the command and some helpful hints are shown in a window. I was wondering if the content of these windows is editable and if so where this contents reside and how I can add content for my own commands.
Answer: In principle yes. It is extracted from latexhelp.html. However, adding content may be a bit cumbersome. Afaik, you have to list the command in the alphabetical index and create a block below. Try copying the structure of an existing command.

Are command tips in Texstudio editable


In The Magicians why was Q considered for advancement with Alice and Penny?

Question: Alice showed exceptional natural talent as well as she was top of the class. Penny took his exam test in record time and also seemed to be a natural. Other than Quentin's final Intro test he didn't seem to have any remarkable progress. The intro test was explained to him to be a well known first time magic use fluke. He didn't seem to be excelling in class at least not like he was used to before he got to Brakebills. So why was he even considered for advancement?
Comment: Just finished reading this book. It was awesome.
Comment: @OghmaOsiris Same here. I'm waiting until this weekend to read the sequel. Th Magician King.
Answer: Warning! Dont read this answer if you havent finished the book as it pretty much gives away the ending, but answers the question.
I think he was considered because of his potential and

 Because the Watchwoman (Jane Chatwin) was controlling the events of the book and influencing them as they were happening because it had to be HIM and his gang to defeat the Beast in Fillory. If Q didn't advance a year, he wouldn't have made friends with the Physical Kids like he did, wouldn't have ended up with Alice, and Penny wouldn't have ended up a hermit studying the Neitherlands.
Comment: Interesting thoughts.
Comment: That does make a lot of sense. After all another question I had was how Fogg knew her, but if she was able to nudge things at Brakebills that would make sense.
Comment: Okay I read The Magician King and it had not further details to add. I think your answer is the most plausible as Dean Fogg did seem to know who Q was talking about when he described Jane.
Answer: Oghma's comment makes sense. I would also like to add that Quentin is an excellent pupil in his normal high school while exhibiting unhappiness and seemingly depressed most of the time. The story is mostly narrated around what Quentin sees and feels. It is quite possible that Quentin is a competent student of magic, on par with Penny and Alice, but he does not recognize this or does not give much credit to his own skills and talent.


Slider-less time selection.

Question: I'm using the default datetime picker with rails.  I'm mainly focusing on the time aspect of this because for my purposes the day will rarely ever be changed.  I'm looking for some sort of way to make selecting a time a little more elegant.  I'd like to avoid sliders if possible.  Any suggestions would be great.
Comment: Are the times full ranged, or are there only limited values which are acceptable? That is, are there 24 values on the ``Hour`` menu and 60 values on the ``Minute`` menu? Or are the times limited to (say) 15 minute increments between 7:15am and 5:45pm?
Comment: Its mostly for business hours, so like 7am - 7pm.  But I want to be able to say if you are off this week, you'll be returning on X date.
Answer: If you are specifically interested in a time picker, Maxime Haineault's implementation looks good. It minimizes the time selection procedure to single click.

Though I personally feel a lot comfortable if I can type the value directly. Keeping this in mind, there is an interesting datejs project which quite comfortably accepts natural input.
You can also follow these SO discussions on this topic: https://stackoverflow.com/questions/1245245/jquery-date-time-picker and https://stackoverflow.com/questions/476822/jquery-time-picker
Comment: This is the first time I've seen datejs.  Very interesting.  The first plugin you mention though only seems to accomodate time, not the date.
Answer: I've went across the same need today and found the KendoUI's DateTimePicker widget which brings some good inspiration.
It combines a date-picker and a time-picker in the same field: they are accessible through icons, and the date-picker is shown above the field while the time-picker is displayed below it.
The date- and time-picker parts look like this:

EDIT:
Continuing my research on the subject I've found other possible approach like the WPF DateTimePicker from Telerik and the Mobiscroll javascript library (especially the timepicker inspired by the Windows Phone UI).
One of the most innovative approach is this proposition from Dave Cortright:
Comment: The [Dave Cortright's idea](http://www.kpao.org/2009/10/steal-this-idea-a-better-time-picker-widget.html) might've actually been implemented in [Clockface](http://vitalets.github.io/clockface/) by [github.com/vitalets](https://github.com/vitalets).
Answer: I rather like the approach taken by the Calendars app (available on iOS).
By default, it shows this view (focus on the bottom parts of the screenshots):

It does not allow for single minute precision. However, for a lot of applications, I'd imagine that being acceptable. I rather like the division of the time that was chosen. Rather than AM/PM ranges, the upper bar contains the day-time hours, and the lower bar contains the night-time hours. The only weird result of this, is the placement of the 0:00 to 07:00. It right after the 20:00 to 23:00 range, but it represents the time before it. I guess a three-bar variation (with empty parts in them) would be clearer, but not as visually appealing.
On clicking the Date button (or on the All-day button), the view changes to this:

This is of course all in an iOS app, not a website. But you might use a similar approach online, I think.
Comment: I really like this approach, but I am wondering if somebody has already this approach on the web. If I don't find something useful, I might try writing a jQuery plugin.
Answer: I would suggest a combination of the usual dropdown calendar and allowing users to type in the time themselves, with a fallback on dropdowns for mobile devices if you need to accomodate those. There are plenty of dropdown calendars out there, like the jQuery UI Datepicker, that you can drop right in. Good ones are nice and friendly, and also degrade gracefully.
As for the time, of course, just one simple textbox would do, I think. A fancier alternative would be to have a combined box, here's a quick example.
Answer: Lots of interesting and novel answers here, but I think you can solve your problem with something simpler.
Some well-known services use a combination text-input/drop-down for the time--and a similar text-input/calendar-picker for the date.
This allows people to either pick from a list of options (quick for mouse users, low precision) or to type an exact value (higher precision, quicker for keyboard users).
Most importantly, your users will probably be familiar with this pattern :) Remember, don't make them think!
Google calendar:

Zipcar:

Slider-less time selection.


RabbitMQ Cluster in Docker Container among different hosts

Question: I want to create a rabbitMQ cluster that is very resilient to failures.
So far I've managed to create a cluster with three nodes, each of these nodes runs inside a docker container. To enable the nodes to join a cluster, the hosts needs to know each other via links.
Now, the whole architecture runs in the cloud (on AWS to be precise). So far, my containers can only be linked with one another, when they run on the same AWS-instance. I want to create the cluster in a way that nodes can lie on diffrent hosts.
So far I've tried:

Using federation / shovel instead. This does not serve my purpose, because I need CP from the CAP-Theorem and not CA. I need my nodes to be all replicas of one another and to be able to act as the same broker to clients.
Creating a docker swarm. I am able to set-up the docker swarm and connect two instances via docker swarm. But if I try to run multiple rabbit-containers on this swarm, they either are placed on the same node or I cannot link them with one another. So I end up with the same constellation, of all my hosts running on the same node.

Is there any solution or other approach, with which I could create a rabbitmMQ-cluster inside docker containers among different AWS-instances / hosts?
Comment: How about docker overlay network? https://docs.docker.com/engine/userguide/networking/dockernetworks/#an-overlay-network
Answer: You mentioned "To enable the nodes to join a cluster, the hosts needs to know each other via links" .. but I'm not sure why you require the links.  The main thing is for each of the containers to be able to locate each other, which is basically a service discovery problem. I've done something similar (with rabbitmq) using consul on a bunch of different VMs (not even using swarm), but if you're already running a swarm cluster then you might be able to hit the API to discover other instances of the container?


Can I use dual license for a python package which uses library with GPL license?

Question: I have created a python package with several files and directories out of which only one particular module requires a library (PyQt) with GPL license. Since GPL license of the used library puts a restriction on the program to have same license. I was wondering if I can have separate license for other files of the package?
Comment: Note that while PyQt is GPL (or you can buy a commercial license), PySide/Python for Qt is LGPL. Consider porting your project to PySide/Python for Qt and you can avoid this issue entirely.  Normally, there are only minor things (if any) that you would have to change. For example in PyQt there is a Python version of QString defined that acts like Qt's QString. In PySide they generally str (Python strings) instead. So if you depended on QString in your code, you would have to code around that; if you didn't, then maybe no change would be required.
Answer: The GPL license on the library does not strictly imply that you must use the GPL license on the program. The GPL license requires that the rights that users get under the GPL license are extended to all code in the application, but that can also be achieved by using a GPL-compatible open-source license.
Additionally, the GPL license requires that you inform recipients that the terms of the GPL apply.
As long as you inform the recipients of your program that the GPL terms apply due to and as long as there is a dependency on PyQt, you can use a dual license (with one of the licenses being GPL compatible), or even a single GPL-compatible license for your own code.
Answer: A GPL-licensed library requires that any programme making use of it is also distributed under the GPL. However a GPL-licensed programme does not require that all libraries (or modules) it uses are also GPL-licensed. The modules can be under GPL or other licenses which are more permissive (like BSD, Apache, LGPL etc).


Is the age restriction lower in Japan than in western countries?

Question: For instance, the anime Darker than Black is R-17+ (violence & profanity) in the West, but is it higher or lower in Japan?
Comment: What type of media are you specifically referring to? Different media have different regulators.
Comment: i am referring to anime
Comment: Where are you seeing this rating?
Comment: As far as I know DTB has not been rated as "R - 17+ (violence & profanity)" by any Western TV ratings organization. [IMDB](http://www.imdb.com/title/tt0995941/parentalguide?ref_=tt_stry_pg#certification) doesn't list any such rating.
Comment: They have a rather different standard on profanity over there, one time Sonic the Hedgehog gives a very emphatic yell of "s**t" in an anime.
Answer: The television rating system in Japan is the same as the movie rating system.
Their regulations are as follows:
Unrestricted

G: General audiences
PG12: Parental guidance suggested. Some content may be unsuitable for children under the age of 12.

Restricted
These are regulated, and all movie theaters are required to check for ID. Allowing in an underage child is a criminal offense.

R15+: Restricted to teenagers 15 and over only.
R18+: Restricted to teenagers 18 and over only.

It is a lot more difficult to regulate television watching than to regulate movie-watching, so just because a rating is given for a television show, it doesn't mean that it is being followed, whereas in a movie theater, at least, it can be regulated. Frequently, in America, for TV-MA, a warning will be given that the show may not be appropriate for children under the age of 17.
Darker than Black was actually rated TV-MA in America, not R. R is only used for movies, and Darker than Black is a TV series. The rating is given here.
I cannot (at the moment) find what the Japanese rating is for Darker than Black, but presumably it was either R15+ or R18+.
Comment: Side note: R15+ isn't like the MPAA's R where you can get in if accompanied by a parent. Both R15+ and R18+ are strict no-entry, like the MPAA's NC-17.
Comment: Are you claiming that Eirin rates TV series as well as movies? I can't find any solid sources to back that up, including their own website. Even if they do, I'm not sure that late night anime get rated.
Comment: Both http://rating-system.wikia.com/wiki/Eirin and http://en.wikipedia.org/wiki/Television_content_rating_systems#Japan say it, though they may be pulling from the same source/each other. I have no first hand experience, but it is from what I found.


Is the SO prototypejs tag correct?

Question: I just posted a question to StackOverflow regarding the PrototypeJS library. I tagged my question with [prototypejs] because I figured the [prototype] tag was too generic, probably for function prototypes. But [prototypejs] only has ~89 usages making me question if it's a duplicate tag, and if I should have tagged my question as [prototype].
Answer: Tag Overload Exception
[prototype] can mean various things depending on the context, and most likely there are some questions about PrototypeJS that are tagged simply prototype, but the one you used is better.
Seems like there were other people with the same doubt, and said What the hell, better safe than sorry.
Answer: [prototype] is too generic - it's the name of a language feature in JavaScript, and should probably have been limited to that...
Unfortunately, it isn't. Of the 912 questions tagged prototype, a good many of them have nothing to do with prototypes and everything to do with the Prototype.js library. Which makes it rather difficult to find questions about, say, prototypal inheritance...
I commend you for choosing a better tag... Let's hope your thoughfulness isn't rewarded with indifference.

Is the SO prototypejs tag correct?


Can a third-party flash made for Canon be used on a Contax G1?

Question: Is it feasibly possible to attach a third party Flash made for Canon on a Contax G1?
Answer: You can attach third party Canon flash to a Contax camera but, because the contacts are not the same, it would be advisable to cover up or blank off all but the center contact, and then use the flash in manual mode only.
Answer: Theoretically, yes. The Canon hotshoe and the Contax G1 hotshoe are both ISO-compatible, so physically the flash should fit, and the ground (rails) and sync signal (large contact/pin in the center of the square) should be interchangeable.
However.  You do want to try and do some research to find out what the safe sync voltage threshhold is for the Contax G1.  Since it's a film camera, it should probably be ok, especially if you have a low-voltage digital-era Canon EX speedlite.  But if you're using a vintage film-era Canon flash and the sync voltage on it is very high you may want to get a Wein Safe Sync or other voltage limiter just to be on the safe side so that you don't fry the G1's hotshoe.
Be aware, too, that you won't have anything other than sync. No TTL, no HSS, and no way to set the flash's power output other than to put it into M mode and dial in the power level you want.


If an in-the-money put option is not exercised by 4 p.m. ET on the expiration date, does it become worthless?

Question: If an in-the-money put option is not exercised by 4 p.m. ET on the expiration date, can the shares be assigned to the seller of the put option, or does it expire worthless?
Answer: Options that are in the money by more than one cent are automatically exercised, by most brokers. If you hold a contract without instructing the broker not to auto-exercise, and you let it expire, you run the risk of waking up Monday to a losing position. Best to check to see your own broker's rules for auto-exercise.
Answer: Apart from auto-exercise, you may have until as late as 5:30 pm ET on the expiration Friday to exercise.
Answer: If an option is one cent or more  ITM at expiration, the Option Clearing Corp (OCC)  will automatically exercise your options whether they are  long or  short.  This is called Exercise by Exception.
For equity options, you will end up with a position in the underlying.  Index options are cash settled.   A broker's threshold for automatic exercise may or may not be the same as OCC's.
If you are long the option, you can designate to the OCC via your broker that your options are not auto exercised at expiration.  This would make sense if they are ITM by pennies and your commission to close the position exceeds the ITM amount.


Lightning strike on aircraft

Question: Is an electromagnetic pulse sufficient to account for the complete dscharge of an aircraft struck by lightning?
Answer: It is not quite clear what you mean by an electromagnetic pulse and why you seem to assume that an aircraft struck by a lightning will be completely discharged.
So, I'll try to describe what I believe might happen during a strike and, hopefully, it'll clarify matters for you.
As clouds get charged (due to processes outside the scope of this question), they are "looking" for an opportunity to get rid of their charge by sharing it with any conductors close enough to be reached, like earth or other clouds or an opposite side of the same cloud that happen to carry a charge of an opposite sign.
From this prospective, a passing aircraft is a legitimate target, just like another cloud but even better considering that its skin is highly conductive and its geometry includes a lot of sharp edges: both of these features will facilitate the formation of strong electrical fields and the initiation of a discharge.
When a discharge or a lighting strike between a cloud and an aircraft occurs, the aircraft ends carrying a fraction of the charge lost by the cloud, i.e., it will be charged - not discharged.
It is likely that an aircraft was carrying some charge before the strike had occurred.
If so, such charge could make the strike more or less likely, depending on the sign of that charge and the sign of the charge in the cloud, but, once the strike occurs, the end result won't depend on the magnitude of that initial charge - it'll rather be dependent on the magnitude of charge in the cloud and on the relative effective capacitance of the cloud and the aircraft.
This is because the initial charge on the plane is likely to be insignificant with the charge in the cloud and will be, so to speak, lost in transaction.
Even in the absence of charged clouds, a charged aircraft will gain and lose charge continuously as it goes. I suppose that, when it passes through a neutral cloud, it could discharge completely, but I am not sure if such discharge could be violent enough to qualify as a lightning strike.
Comment: Thanks! However, I am not sure my question is fully answered. Does the
Comment: Could you complete your question please - it seems to be truncated?
Comment: Sorry! Am I correct in assuming the rate of dissipation of charge on an aircraft depends onthe difference in charge between it and the surrounding cloud?
Comment: It seems that you are not talking about a strike, but rather about a "non-violent" or gradual dissipation or flow of charge. Yes, the rate of such dissipation, facilitated by dissipators installed on most aircraft, depends on the strength of the field and therefore on the difference of potentials between the aircraft and surrounding clouds and therefore on the difference in the charge levels.
Comment: Actually, I was thinking of a direct strike on an aircraft. What is he essential difference between charge dissipation beween a a direct strike and a non-violent event?
Comment: "Non-violent event" is a variation of a corona discharge, which happens when the field is strong enough for the local ionization of air, but not strong enough to cause a breakdown of the whole path to a remote object (arcing or lightning). The strength of lightning, or the discharge rate accompanying lighting, will depend on the strength of the field (potential difference/distance).

Lightning strike on aircraft


Is the size of a photon dependent on its wavelength?

Question: When detecting radio waves in space, we use very large telescopes or arrays of telescopes.  But according to QM, aren't photons point particles when measured?  Does a photon with a large wavelength have a wider probability distribution with regard to where it can be expected to be detected?  Is that why photons with long wavelengths require large telescopes to be detected relative to shorter wavelength photons?
Comment: Related: http://physics.stackexchange.com/q/53023/2451 http://physics.stackexchange.com/q/95905/2451 and links therein.
Comment: More on [size of photon](http://physics.stackexchange.com/search?q=is%3aq%20size%20photon).
Answer: We can describe light as either a wave or a particle, and we normally choose whichever is the best description of the situation we are modelling. If you're trying to understand diffraction then a wave description is simplest to work with, but if you're dead set on using photons then it can be done.
The radio waves coming from space are delocalised in the sense that they have no precise position. If you insist on modelling these as photons you would have to treat the wave as a superposition of all possible photon positions. When we detect the photon with our radio dish we have pinned the photon position down to somewhere in our dish. We know the photon interacted with our dish somewhere, but we don't know precisely where. If our dish has a diameter $d$ let's say the uncertainty in the photon position, $\Delta x$ is $d$. Then we appeal to the uncertainty principle to get $\Delta p = h/d$.
Because there is an uncertainty in the momentum there is an uncertainty in the angle from which the photon came. To see this look at the following diagram:

The uncertainty in momentum produces an uncertainty in the angle of $\alpha$ given by:
$$ \tan\alpha = \frac{\Delta p}{p} $$
If we substitute our expression above for $\Delta p$ and use the expression for the momentum of a photon, $p = h/\lambda$, we get:
$$ \tan\alpha = \frac{\lambda}{d} \tag{1} $$
And that's why if you want good resolution you need a large dish, and why large wavelengths give poorer resolution than short wavelengths.
That equation (1) ought to ring a bell, because it's very similar to the classical expression for the angle of the first minimum in the Airy disk diffraction pattern:
$$ \sin\theta \approx 1.22 \frac{\lambda}{d} $$
By choosing a particle description, invoking the uncertainty principle and waving our arms around a bit we have ended up at essentially the same result as doing a classical analysis using a wave.
Answer: The photon's field of influence in this case really is as big as the antenna! If you think of gathering photons one by one from distant stars, then the quantum state of each photon propagates through space and time precisely following Maxwell's equations. I talk about this idea in great detail in my answers here, here and here.
So, for one photon at a time reception, or many unentangled photons at a time, classical optics / electromagnetics is indeed exact for the design of the antenna systems. If you image with a smaller aperture, a photon's field of influence is going to lie more and more outside the antenna and the probability that it will be absorbed by matter outside the antenna increases relative to the probability that it will be registered by the antenna. You calculate the probability density from Maxwell's equations as a normalised intensity at all times: this gives the probability density that the photon will be absorbed at a single point (i.e. a lone absorber atom) at different places. Your design goal is to maximise the probability that this absorber will belong your detection hardware.
Answer: The electromagnetic fields of a photon are confined in the cylinder with length of half the wavelength, whose radius is proportional to square root of the wavelength. Here, it has the definite frequency and is different from the well-known wavepacket which consist of the plane waves of different frequencies, as described in the paper: Shan-Liang Liu. Electromagnetic fields, size, and copy of a single photon. ArXiv: 2016, 1604, 03869.
Comment: What you you mean bu the radious of a photon? Are you thinking in terms of wave packages here? Could you explain more withour refering to your own newly published ariv paper.


FCP software development.

Question: I heard that FCP (final cut pro - editing software by Apple) has stopped developing. Any editing software if not updated will become useless in short while. So FCP will not be of much help if they are not going to develop it. Is it true that they have stopped the development?
I have heard this especially from people who are working on Adobe.
Comment: There's a big difference between FCP and FCPX.  If you're sure you are talking about FCP, then yes, support disappeared a long time ago.  FCPX, however received an update last weekend.  In either case, I don't really think this question is appropriate for this forum in its current state.  This is not a rumor site.  It's not a place for idle speculation or open ended questions.
Comment: You might want to reword your question a bit, at it's current state its rather confusing to read.
Comment: @ProfessorSparkles Sparkles I agree with you. Even I wanted to delete the whole question itself! Now it is not making much sense to me! I am myself wondering why I have asked this question when FCP has launched FCP 10 (version - .2) quite recently! but still I have not thinking that it will be an insult of the person who has answered it.
Answer: Your question is simply mistaken on multiple levels.  To the best of my knowledge, there has been no announcement about an end of development of Final Cut Pro.  FCPX is the current version and still gets updates and it is still a very popular piece of software.
Additionally, even if they stopped development today, your premise that editing software rapidly becomes obsolete without constant updates is also 100% incorrect.  Video formats change at a near glacial pace for the tech world.  Almost decade old software can still be used comfortably today and often is.  Outdated software results on missing out on some interesting new features like hardware acceleration and 64 bit support, but it still gets the job done just fine.
In fact, part of the reason that Adobe switched to their subscription model is because many users would make a habit of only upgrading every 2 to 5 versions of the software.  It is commonplace to use software that is 3 to 5 years old or more.
All in all, it sounds like you are probably confused about what you are hearing and even if you are not, there is no reason to worry for some time yet.

FCP software development.


Maximum recommended cassete size for 26 inch wheels

Question: Hello I was looking to upgrade my 2011 Specialized Stumpjumper Hardtail comp to a 1x drivetrain. 11 speed Shimano deore M5100 caught my eye with its low price and wide range (max 51 tooth cassette). But can i run a 51 tooth cassette on a 26er? I'm afraid the derailleur in the lowest gear would hang so low it would interfere with the tire or the rim. Thanks.
Comment: Why do you even consider this? Converting a hardtail to 1× is generally a _downgrade_, unless you're replacing a low-quality and/or worn out 3× with a top-end new 1× (but then replacing it with a good 2× would be an even better upgrade, though those are unfortunately getting more and more difficult to obtain). Only on full-sus  bikes does 1× play out its advantages, but especially on a 26" bike even a good 1× will probably leave you spinning out on flat asphalt or gravel.
Comment: @leftaroundabout 1x lets you go up to around 35km/h with an cadence of 90rpm, that's not sustainable for a long time on flat asphalt. Even less on gravel. If you want to do this often, then a MTB is the wrong bike for you, a road/gravel bike would be better.
Comment: @airace3 an MTB with 2× is the right bike (certainly for me) because it works great _on both_ asphalt and proper offroad. Of course this requires relatively light-running tyres and riding in a somewhat aero position. Sure, my gravel bike makes the latter a little bit easier, but on the flip side it's _much_ worse on rooty off-road than my hardtail MTB. I don't sustain 35 km/h for a long time with either bike, but I do like to go faster than that on shorter rides, and on longer tours I like the ability to ride a tailwind at low cadence.
Comment: @leftaroundabout I have a 3x10 with 24-33-44 gears in the front and 11-36 cassete. I like the range but on rougher terrain the chain slaps alot and sometimes even falls. From my understanding, I would need a 1x derraileur with a clutch to fix this. Or do the 2x deraileurs with a clutch work just as well?
Comment: @KarelPrdel yes, older 3× are noisy but the clutched 2×11 on my hardtail works almost as reliably as the 1×12 on my enduro bike. Only on extremely rough descents, the chain sometimes comes off (because it's not a narrow-wide chainring), but also only when riding so fast that it's plain painful without rear suspension. And even when the chain does come off, shifting once back-and-forth with the front derailleur is usually enough to get it back on. Really, I think the widespread opinion "1× is better" just stems from the fact that people compare old 3× with new 1×, so it's not a fair match.
Answer: It's totally doable to use these large cassettes on 26" wheels.
Some high end children's MTBs still use 26" wheels and are sold using such cassettes. For example COMMENCAL Meta HT JR 26" with Sram Eagle 11-50 or Scott Ransom 600 26" using the deore M5100 11-51 cassette and derailleur.
While modern 29ers with the same gear range typically use 30 or 32 tooth chainrings, you should opt for 34 - 36 tooth on 26" to get a similar speed range. The smaller diameter acts like an overall gear reduction.
Answer: The wheel diameter is not related to the maximum cog size on the cassette.
Instead the restrictions are:

The maximum tooth count in the derailleur's specifications
How far over the maximum you can push it
Whether you have a hanger-extender installed
The maximum capacity in your deralleur's specs
The difference between your front chainrings (if more than one)

So a boring 11-32 cassette in a 1x system needs a derailleur with a capacity of 21 or more.
If we select the 1x derailleur from the M5100 groupset as per https://bike.shimano.com/en-EU/product/component/deore-m5100/RD-M5100-SGS.html  it has specifications of

Capacity 40 - the length of chain it can gobble up is some number of links equivalent to 40 teeth on the cogs (which is not 40 links, more like ~20)  This is the difference between fully stretched out and folded up so the chain almost touches.

Compare those specs with the double derailleur at https://bike.shimano.com/en-EU/product/component/deore-m5100/RD-M5120-SGS.html and you see it gets more complex.
If you're hoping to use your existing derailleur, look up the published specs and compare.
Comment: Line 1 - I suppose if the cassette was large enough that it hit the ground, or made the derailleur hang low enough to hit the ground, then that's a limitation based on diameter.


Can you cancel a fixed-income annuity contract anytime?

Question: Can you cancel a fixed-income annuity contract anytime? Why or why not?
Comment: Presumably depends a lot on what the contract says.
Comment: Yes, you can cancel a fixed-income annuity contract anytime.  All you have to do is die.  Other than that, unless you purchase a rider that allows this (if it even exists) then no, there is no cancellation.
Answer: Most traditional annuities are purchased; you give them money once and they promise to send you checks on a regular basis for the rest of your life and/or the lives of anyone else you want to cover. Think of it as a kind of life insurance product; you are paying them to guarantee that you won't outlive this money.
I have recently found that there are some exceptions where you can withdraw your principal again. Presumably without interest other than what they gave already paid you, and I presume you pay a premium for flexibility in the form of lower return. Read the contract carefully to make sure you know what you are agreeing to.
I'm sure there are intermediate mixed time-deposit/insurance products, though I haven't investigated the full range. Generally the longer the period before you expect the principal back, and the less of the principal you expect back, and the lower your expected lifespan, the higher your checks from the annuity will be. I'm getting a guaranteed 8% on mine, but that's a pure purchase insurance product.
When considering annuities, also remember to check out charitable remainder funds, which many nonprofits now offer. These offer a lower cash return than a for-profit annuity might, but have tax advantages which offset that -- and if you're going to make a large legacy gift anyway (and are sure you won't change your mind) this can be a good option, letting them lock in the donation for planning purposes while letting you continue to draw income. I've seen some fairly attractive rates on these recently.
Comment: **Most annuities are purchased; you give them money once and they promise to send you checks on a regular basis for the rest of your life and/or the lives of anyone else you want to cover.** No.  There are fixed annuities for as little as two years.  Variable annuities come in as short as 3 years. Step-up annuities tend to be 5-6 years.  Fixed tend to allow either the interest or a 10% withdrawal per year (gains come out first, then principal) though with short term fixed annuities, it might not be until the 2nd year.
Comment: An "X" year fixed annuity at 5% is just like an "X" year 5% CD except that the annuity is tax sheltered and may allow some amount of withdrawal each year, typically 10% or the annual interest.  They are dissimilar in that a CD has FDIC insurance. It has nothing to do with Whole Life so don't go down that rabbit hole.
Comment: Rephrased/expanded. I'm not sure I consider the shorter-term arrangements annuities, but by whatever term it's a valid point.
Comment: You can consider the shorter-term arrangements annuities to be whatever you want but the industry defines them as fixed annuities with the same features of longer term FA's (tax sheltered, annual withdrawal features, allowable tax free 1035 exchange at maturity, etc.)
Comment: @BobBaerker What do you mean by "for as little as two years..."?
Comment: I've seen fixed annuities whose duration is 2-10 years.  For all I know, there may even be a one year fixed annuities.
Comment: Still feels to me like the same problem as Whole Life: to achieve that result, under the covers they are mixing investment and insurance products, and the combination may or may not be a good one depending on how those components are designed. Read the fine print, understand exactly what is being offered and how it's results may vary, but what makes sense. I find this particular combination more confusing than helpful, but de gustibus...
Comment: **Most traditional annuities are purchased; you give them money once and they promise to send you checks on a regular basis for the rest of your life and/or the lives of anyone else you want to cover.**  That would be an Income Annuity.  Some other types of annuities are Variable, Fixed, Step-up, Indexed and the above is not applicable to them.  Fixed will return your principal whereas Variable and Step-up annuities could return much more or less, depending on the market's performance.
Comment: Something that I recently learned is that all states have a nonprofit guaranty organization.  All 50 states protect at least $250k per customer, per company. The max is $500k in 4 states.
Answer: There are different types of fixed annuities.  Some are irrevocable.
I'm going to assume that you are referring to one that is for "X" years at Y% with the principal being returned at the end of the surrender period.  These tend to allow a withdrawal of 10% a year or an annual withdrawal of interest.  Sometimes, the withdrawal provision may not begin until the second year. You cannot just cancel it and get your money back without penalty.
If you close the annuity before the end of the surrender period, you may incur significant surrender charges and possibly, loss of the income.
The bottom line is that the terms of the contract will determine what, if anything, you can do. This varies from contract to contract and company to company.
Comment: That is an income annuity, aka immediate annuity or single-premium immediate annuity (SPIA). It is irrevocable
Comment: I'm talking about fixed-income, not necessarily fixed-interest. So fixed-income annuity pays one monthly income until one pass away right? I'm saying if you can just cancel this kind of annuity contract and get your lump sum minus any income already paid anytime?
Comment: So you're saying fixed-income annuity means income equity? So I cannot just cancel the annuity contract anytime after purchase?
Comment: Most US states require a grace period, generally 10-30 days. An insurance company may provide a longer free look period.  Beyond that, any cancellation is going to incur penalties, unless it's an irrevocable annuity.
Comment: Ok, so if I can take the penalties and the contract said I can cancel, it's cancellable?
Answer: Fixed-income annuity contracts typically come with specific terms and conditions regarding cancellation. Whether or not you can cancel such a contract anytime depends on the terms outlined in the contract itself and the regulations in your jurisdiction.
In general, fixed-income annuities are long-term contracts designed to provide a steady stream of income for a specified period or for the remainder of the annuitant's life. Canceling such a contract prematurely may result in penalties, surrender charges, or loss of accrued benefits.
It's essential to carefully review the terms of the annuity contract, including any surrender charges or penalties for early termination, before deciding to cancel. Additionally, consulting with a financial advisor or the insurance company that issued the annuity can provide specific guidance based on your individual situation and the terms of your contract.
Comment: Please see https://money.meta.stackexchange.com/questions/3082/use-of-chatgpt-and-other-ai-generators-is-banned


Why aren't the Winter bash hats available in the meta site?

Question: Why aren't the Winter bash hats available in the meta site? Is it a bug or a feature?
Comment: many of the stackexchange sites seem to think tex.sx is an inconsistent feature.
Comment: Some people (including me) like strange things...
Comment: @marczellm -- i haven't got time to dig for citations now, but from the "behavior" of newbies on tex.sx who come from other established sites, it is clear that our "community practices" are rather uncommon.  for one thing, politeness and manners are the norm here; the practice regarding downvotes is one measurable example of that.
Comment: Well we didn't opt in to the whole thing, so ...
Comment: Those winter bash hats are a _very_ strange thing...
Comment: @StiffJokes Then maybe it's part of the strangeness that the hats aren't available on meta :)
Comment: I am inclined to call it as either a bug or an inconsistent feature.
Comment: Well, we cannot see the obtained hats. But I doubt if at least one of them is not available in a meta site. :-)
Comment: @barbarabeeton Can you give an example of that attitude?
Comment: @marczellm: Another example of  odd things is a special typographical convention  to type with lowercase.  No offense. :-)
Answer: It is status-bydesign, as per-site metas (or child metas) don't actually have an exclusive profile. :( The only exclusion is Meta.SO, since it covers network-wide meta-related content, and have individual user profiles separate from StackOverflow.
As reference, see Hat not showing on site meta.


Spotify API models.SEARCHTYPE.SUGGESTION not working

Question: As the user types an artist name to search we want to display a drop-down list of suggestions based on what the user has typed so far.
For example, if the user has so far typed "Bob Dy" we would like to list "Bob Dylan","Bob Dylan & The Band", and "Willie Nelson;Bob Dylan" just like the standard Spotify Radio App does.
We are trying to use the Search API call to retrieve the list of artists to display.  I assume we want to use the  models.SEARCHTYPE.SUGGESTION option however when using that option we always get an empty list.  The models.SEARCHTYPE.NORMAL option does return a list when there is an exact match such as in the case of entering "Bob" or "Bob Dylan" but not "Bob Dy".
Could you please tell us what we are doing wrong?
The documentation we are using is:
http://developer.spotify.com/download/spotify-apps-api/reference/833e3a06d6.html
Here is the code we are using:
<code>       var search = new models.Search('artist:"Bob Dy"');
       search.localResults = models.LOCALSEARCHRESULTS.IGNORE;
       search.searchArtists = true;
       search.searchAlbums = false;
       search.searchTracks = false;
       search.searchPlaylists = false;
       search.pageSize = 10;

       search.searchType = models.SEARCHTYPE.SUGGESTION;
       //search.searchType = models.SEARCHTYPE.NORMAL;

       search.observe(models.EVENT.CHANGE, function() {
           console.log('[models.EVENT.CHANGE observe]', search.artists);
       });
</code>
Answer: Seems like the normal search input in Spotify doesn't support auto suggest for prefixed searches like "artist:Bob Dy". The code below works for me though.
<code>var search = new models.Search('Bob Dy', {
    'localResults'    : models.LOCALSEARCHRESULTS.IGNORE,
    'searchArtists'   : true,
    'searchAlbums'    : false,
    'searchTracks'    : false,
    'searchPlaylists' : false,
    'pageSize'        : 10,
    'searchType'      : models.SEARCHTYPE.SUGGESTION
});
search.observe(models.EVENT.CHANGE, function() {
    search.artists.forEach(function(artist) {
        console.log('[models.EVENT.CHANGE observe] - Found artist %s',
                    artist.name);
    });
});

// Do the search, nothing will be fetched
// if this row is not executed.
search.appendNext();
</code>


Why is a slit needed in Young double slit experiment?

Question: Why is a slit needed in youngs experiment? Can two coherent light sources not undergo constructive and destructive interfernce without the need of a slit?
Comment: That would be an interferometer
Comment: The answer to thw question "Can two coherent light sources not undergo constructive and destructive interference without the need of a slit" is to be found here https://physics.stackexchange.com/questions/630/is-it-possible-to-observe-interference-from-2-independent-optical-lasers
Answer: Slits create a convenient setup, but are not the only way to investigate the wave properties of light. In fact, Thomas Young did not use slits in his famous experiment.
"Strictly speaking, there was no double slit in the original experiment as described by Young. Instead, the sunlight reflected off a steering mirror passed through a small hole in a paper, and the resulting thin light beam was then split in half alongside a paper card."
Young's interference experiment
"Thomas Young, speaking on 24 November 1803, to the Royal Society of London, began his description of the historic experiment. His talk was published in the following year's Philosophical Transactions, and was destined to become a classic, still reprinted and read today."
Thomas Young
Philosophical Transactions of the Royal Society. 94: 1–16.
Answer: If you mean the first slit in the  original Young's design

It is because in order for interference effects to appear the wave impinging on the double slits has to be coherent, i.e. the phases known. Best would be a plane wave, but at that time there were no lasers, as dmckee has observed in the comment, and the way to get a mathematically describable wave with phases known is passing an incoherent beam through a small slit so that a radial wave appears. There are details in the answers to this question here.
If you mean two coherent beams in space, the experiment has been done and yes two beams split off from the same laser, so as to have two coherent beams, do exhibit in space interference effects. See this youtube video .
Answer: The challenge is to have two light sources that are mutually coherent. Two separate laser sources would not produce an interference pattern, because, although they are separately coherent (each has a finite coherence length), they are not in general mutually coherent; there does not exist a fixed phase relationship between the two separate sources. To make them mutually coherent is a nontrivial task. One would have to lock one on the other, which in the end would imply a very complicated experiment compared to just having two slits.