Both t-test and F-test are significant, do I report both?

Question: I undertook a large study (N about 200 in both control and treatment) in which one of the user ratings is significantly different (p < 0.0001). When I ran the unpaired t-test, the F-test also returned significant (p = 0.0003). This violates the t-test assumption of equal variances, but I figured this was OK with these large sample sizes (it's still highly significant with Welch's correction anyway). The t-test tells me that the two means are different, and the F-test tells me the standard deviations are different. Should and can I report both? Whenever I see a site talking about reporting the F-test, it's always in the context of ANOVA, never alongside a t-test. This makes me think that reporting it here isn't common practice.
Comment: *Why* did you run both tests? What questions you were looking answers for? You use those methods to test certain hypotheses and report the results that are consistent with your research questions. There is not point in running any possible test...
Comment: Yes, I know. But *why* did you use them? What were you interested in? If you want an answer for both questions then you report both.
Comment: "Whenever I see a site talking about reporting the F-test, it's always in the context of ANOVA, never alongside a t-test" - but is that because you're looking at a different type of F-test? In particular, for linear models such as ANOVA or regression, an F-test is to see if the overall model is significant (compared to a null model) whereas you seem to be using an F-test to compare variances?
Comment: @Tim the F test was for equality of variances and the t test was for equality of means, that's why.
Answer: It's not clear what you did your F-test for, but I am assuming for now it was a test for equality of variances. If not I will edit my answer. But if it was a test for equality of variances, it probably wasn't a good choice because the F-test assumes that your data were drawn from a normally-distribution population, and is very sensitive to departures from normality. There are alternative tests which are more robust - see this question for discussion. But before choosing a better test for equality of variances, you should consider whether you really want to test for it at all.
A two-stage approach of using an equality of variances test before deciding on whether to use a t-test or non-parametric test, is strongly advised against because it means the operating characteristics of your test are uncertain - see also this question which is closely related to yours. For a reference, see Zimmerman, D.W. (2004),  "A note on preliminary tests of equality of variances", Br. J. Math. Stat. Psychol., May; 57(Pt 1): 173-81.
It's a good idea to use a Welch-corrected t-test if you're in any doubt whether the equality of variances will apply - see this question and accompanying citations. If the variances are similar in your samples, you'll only have a small degrees of freedom penalty applied, so you don't need to worry that you'll lose lots of power by applying the Welch correction in a case where the variances are equal.
If you don't even think that the conditions for the Welch t-test are met, then you should be applying a different test such as Wilcoxon-Mann-Whitney. It need not be a big worry that, should conditions for a traditional t-test hold, that you have needlessly lost power, since asymptotically it will have $\frac{3}{\pi} \approx 95\%$ of the power (in large samples) anyway. In small samples simulations show rank tests don't perform much worse than t-tests either. Another alternative might be to apply a Welch t-test on the ranks of your data: it's been suggested this approach is particularly effective when variances are unequal, see Zimmerman DW and Zumbo BN, (1993), "Rank transformations and the power of the Student t-test and Welch t′-test for non-normal populations", Canadian Journal Experimental Psychology, 47: 523–39.
Is the (in)equality of variances something you are generally interested in, in its own right? If so, then it seems perfectly sensible to state whether the difference in variances was statistically significant by writing up the test results (but preferably not an F-test!). If this is simply a side-issue to deciding which test to apply in the first place, then you needn't bother.
Answer: It's not clear why you did both.
Note that the F-test for variances is very sensitive to the assumption of normality; there are better choices for a test of that, if you actually need a formal test.
If you did the test of variances as a check on the assumptions, it's not advisable to test that and choose a procedure based on its outcome. Better to simply not assume constant variance (the Welch test is a good default if you can't reasonably assume equal variance from the outset). [In that case, I'd simply ignore everything you've done as if you hadn't done it and instead do a Welch test and report that.]
If you're actually interested in whether there's a difference in either mean or standard deviation of treatments, then it makes sense to test for (and report) both -- but I still wouldn't do the F-test for variances in that case.
Comment: (+1) Good point re F-test.
Answer: Another approach would be to use the results from the F-test to justify using a test that does not assume equality of means. You could use a nonparametric approach such as the Wilcoxon rank-sum test instead of the $t$ test.
The nonparametric alternatives are more powerful than the $t$ test (and thus preferred) when assumptions are violated. You have plenty of data to run these and I would expect that you will get the same result as with the $t$ test.
Comment: "Another approach would be to use the results from the F-test to justify using a test that does not assume equality of means" - I don't think this is wise. A major problem with using two stages like this - a first test to decide which test to use in the second test - is that the operating characteristics become uncertain. See [this question for some extensive discussion](http://stats.stackexchange.com/questions/121852/a-principled-method-for-choosing-between-t-test-or-non-parametric-e-g-wilcoxon)
Answer: Your question is confusing because you haven't described the experimental design or the tests you used in enough detail for a reader to be sure what you did. What I assume you mean is that you ran Levene's test for equality of variances and found a significant result?
In that case, if you are running a one-way ANOVA, yes, you should run Welch's test and report the F value, p value, and degrees of freedom in the style recommended by whichever group governs the journals you publish in.
The Wilcoxon-Mann-Whitney is also an option, though Welch's is usually more powerful (see Tomarken and Serlin 1986.


I have a public network. How can I prevent the users from visiting bad websites?

Question: I have a friend who owns a coffee shop and he has a public network.
He asked me for a way to prevent the customers from visiting any web site that present a potential threat to the admin (websites that has either sexual content or any kind of extremism). How can I block such sites?
Comment: Pay someone to maintain it, including managing the legal issues of operating such points. You don't want this mess on your hands.
Comment: @JamesTrotter, that is a very sensible alternative - you should put that in as another answer.
Answer: What you need is a web filter. This creates the ability to inspect the traffic and filter it depending on the destination.
Note that, unlike the other answer, this does not need any SSL interception since all you are doing is reviewing the IP names and addresses.
Typically, you will use a product that uses dynamically updated block lists, generally grouped so that you can disable access to whole categories such as gambling very easily.
There are many products that will do this at different price points. One example is Sophos UTM though that is most likely overkill for your needs as it is an enterprise tool. Trend and most of the other recognised security vendors all have web filtering tools available.

If you want something quick and dirty, you can also switch your DNS service to use OpenDNS. OpenDNS also provides dynamically updated web filter lists but they work simply by preventing an IP Address lookup so it is possible to bypass the restrictions - generally by users manually setting their own DNS servers.
Comment: I really doubt this is necessary. You are only trying to demonstrate that you have taken "reasonable" precautions to protect both clients and your assets. SSL interception would open up a whole load of new issues that you simply don't need to deal with and is overly complex and costly.
Comment: You can only see the IP/Domain in question. What do you do for sites hosted on free webhosting for example? Sophos UTM for example, is able to do real content scanning with SSL interception, but you need to get the end user to install the Root CA first.
Answer: You can block inappropriate websites using OpenDNS  Familyshield service to configure which websites can/cannot be seen on your network
Comment: That does not "prevent" since it can easily be worked around by users setting a different DNS server. In addition, FamilyShield is the simple home version. You just need to register your network with OpenDNS to get full access to the block lists.
Answer: I would suggest using a so called SSL Interception proxy.
To get the user to install the CA Root certificate, its possible to use a captive portal, to force the end user to install the CA Root to gain internet access.
This is how to do it:
first, you have a portal page. This portal page must use a VALID certificate. This portal page, lets call it captive.yourdomain.tld , have a valid certificate that is issued by a valid CA already in trust.
On this portal page, you have instructions how to download the .cer CA certificate and how to import it in browser.
Now, from captive.yourdomain.tld, you set HSTS with subDomains activated.
Then, you have a 1x1 iframe, that is loaded from, lets say validate.captive.yourdomain.tld . This validate.captive.yourdomain.tld uses a server certificate that is signed by your CA Proxy Interception certificate.
This validate.captive.yourdomain.tld page also have a form, that auto-submits (using a javascript) valid credentials to access the WLAN network. Best option here is to use TOTP codes or something, to prevent people from bypassing it.
If you want, you could have a terms of service page instead, but the "I Agree" button is inside said TOTP form behind Iframe (instead of a javascript auto-submit, then the iframe needs to be slightly larger). If the user hasn't installed the Root CA, the "I Agree" button won't load, and the user is unable to agree to the terms.
The result is a captive portal, that REQUIRES installing a CA root certificate in the browser to gain internet access at all. Since the page is bootstrapped with a real certificate, user will be prevented access (by HSTS no user recourse block page) if the validate.captive.yourdomain.tld fails to validate, which it would if you haven't imported the CA root.
The user does not need to authenticate to the captive portal, it happens automatically provided you have imported the CA root.
Here is a video how it looks:
https://www.youtube.com/watch?v=5OXbfnG-hdg
(But it can be implemented on any captive portal device tha allows a custom authentication page to be uploaded)

Then when you have done this, you can use any proxy in-between with this SSL interception proxy to filter content by keywords, URL or whatever you see fit.
Comment: Wouldn't that (at least theoretically) allow the coffeeshop to see all content? Even encrypted communication with your bank, logins, etc. Even when not 100% sure of that anyone slughtly computer literate would just deny the certificate and then complain when things do not work.
Comment: This is not what the OP asked for. Nor is it necessary. All that is needed is a simple web filter.
Comment: The URL is visible always as it is the address. This is sufficient for by far the majority of checks you need to make. The best (e.g. most expensive) products are capable of doing dynamic risk scores and these are done outside your network. So personal websites can be marked as untrusted or not depending on your risk appetite and circumstances. Cheaper products still maintain lists and categorisations of millions of sites and will be more than enough for most casual use.
Comment: You can even get these lists for your own use. For example, someone maintains a really good filter list for the Ubiquity EdgeRouter Lite that I use. It would be perfectly acceptable to use that in most small cafe environments.
Comment: @Hennes : Thats why there should be step-for-step instructions. And there will be no certificate popup, either the certificate is installed and then user is automatically redirected and given access, or the certificate is not installed, and then nothing will happen. And yes, the coffeeshop will see all content. But thats the only way to implement viable filtering. If the user don't want the coffeshop to see all content, user should not use the network. And the traffic is still secured from client to coffeshop, so a illegit user cannot snoop on the wireless signals to read the SSL content.
Comment: so after following the step by step instructions, (or a pre-made EXE can be supplied that will auto-install the certificate), the user only needs to refresh the page to gain access. And the function to reject network access if the CA cert is not installed, works on all platforms, on all devices, that support HSTS.
Comment: @JulianKnight The problem is that you can only see the domain/IP of the site in question. If the OP wants to filter whatever is questionable and can get admin into trouble, he needs to scan the content with a web filter. Like Dansguardian, or other content scanner. Also the full URL can be important, especially for questionable sites hosted on free hosting. Also another problem is that you need well and good updated blocklists over "bad" sites. With content scanning, you instead block by bad keywords so each site gets a "naughtyness" score, and too naughty sites are blocked.
Comment: Let us [continue this discussion in chat](http://chat.stackexchange.com/rooms/46305/discussion-between-sebastian-nielsen-and-julian-knight).


What is the difference between preferences lacking "completeness" and being indifferent?

Question: If two preferences are complete, at least one must have a relationship to the other.  If neither has a relationship, doesn't that mean that the consumer doesn't care which one he/she purchases?
Comment: If you never had a pizza or a hot dog before, and I asked you which one you liked better, saying "I don't know" doesn't mean you are indifferent. It means your preferences are incomplete. Colloquially in English, "not having a preference" can either mean you *know* you don't prefer either option more strongly OR it means you *don't know* at all how much you like one or both of the options, so they are incomparable to you.
Comment: I don't understand what you are asking. Preferences describe how you evaluate bundles, But you seem to be talking about the bundles themselves. Perhaps you could provide an two good example to clarify what you.
Comment: The consumer wouldn't know if she cares or not if completeness doesn't hold. E.g. I don't know if or how much I like caviar compared to bread.
Comment: I'm referring to the completeness theorem for rational consumers.
Comment: @BBKing so a lack of completeness is a lack of enough information to decide one's preference?
Answer: As alluded to in the comments the distinction is roughly:

Indifference: The decision maker knows she will receive the same utility from the consumption of $x$ or $y$.
Incompleteness: The DM does not know her preference between $x$ and $y$. (Note, this could stem from a lack of information, or because no preference exists)

So, from a conceptual vantage, the difference is that indifference is the existence of knowledge, whereas incompleteness is a lack of knowledge. While interesting in a foundational/philosophical sense, the distinction is subtle and likely not the reason economists have spent so much thought on the subject. However, the difference has behavioral implications! and this is important for economics.
For example, imagine various choices between "pizza", "hot dog", or "hot dog and $\$0.05$". Perhaps, the decision maker has never had pizza or hot dogs and therefore finds them incomparable. As such, from the choice set $\{p,h\}$ she would choose either (since neither option is known to be inferior[1]). So $C(\{p,h\}) = \{p,h\}$.  Now, the decision maker also likes money, so although she does not know her preference for a hot dog, she will always choose more money to less, all else equal: $C(\{h, h+5\}) = \{h+5\}$. But her indecisiveness regarding the two foods might not be resolvable for 5 cents, so, it is reasonable that $C(\{p, h, h+5\}) = \{p, h+5\}$. But this violates the weak axiom of revealed preference. Such a choice function cannot be rationalized by a complete and transitive relation.
Notice if the decision maker was actually indifference between $h$ and $p$ then, $C(\{p, h, h+5\}) = \{h+5\}$. In summary: incompleteness can cause "thick" indifference curves, and this can violate the basic tenets of rational choice theory.

[1] There are other interpretations of choice under incompleteness, for example, allowing the choice function to return an empty set.
Comment: "There are other interpretations of choice under incompleteness, for example, allowing the choice function to return an empty set."
Do you have a reference for how to construct a choice function for incomplete preferences?
Comment: [Eliaz and Ok (2006)](http://www.tau.ac.il/~kfire/EliazOkGEB.pdf) find necessary and sufficent conditions for a choice function to return all undominated alternatives. I am not aware of an explicit reference regarding a choice function that allows for not choosing anything, but, my intuition suggests: non-emptyness of singleton sets if any only if reflexivity; WARP if and only if transitivity. Therefore the movement from generic non-emptiness to non-emptyness of singletons corresponds to the movement from rationalizing weak order to rationalizing pre-order.


Runescape Slayer rewards?

Question: When slaying how do you receive the slayer reward points? I have completed 34 slayer tasks under Vanaka and haven't received any points. How can I earn them?
Answer: As of 2014, the mechanics for rewarding slayer points has changed a bit and thus the accepted answer is no longer true.
Slayer points can be earned from a few different sources such as completing Slayer assignments or a special challenge from any Slayer Master bar Turael and Spria, by trading in completed Tuska masks, or completing contracts on the Arc assigned by Ling
The smoking kills quest is no longer required to start earning points, it now instead doubles the amount of points gained per task. The values are below and assume the player has completed the quest. Players still earn 5x the points for every 10th task and 15x for every 50th task.

Turael or Spria - 0
Mazchna or Achtryn - 2
Vannaka - 4
Chaeldar - 10
Sumona - 12
Duradel or Lapalok - 15
Kuradal - 18
Morvran - 20

See the Runescape Wiki page on Slayer Points for more information.
Answer: In order to get points for finishing slayer tasks, you must first complete the quest Smoking KIlls. After that, you gain slayer points every time you kill the last monster in a task, starting from the fifth task completed in a row (that is, without discarding a task). You get different amounts of points depending on which slayer master you got the task from (information from this page):

Mazchna - 1 points
Vannaka - 4 points
Chaeldar - 10 points
Sumona - 12 points
Duradel - 15 points
Kuradal - 18 points

You also get 5X points after your 10th task completed in a row and 15X points after your 50th task completed in a row.
Comment: You only gain points if you complete 5 tasks in a row without doing anything else? I completed the quest and I'm still confused.
Comment: Ah, that's not what I meant. You only gain points if you complete 5 tasks in a row without discarding a task by replacing it with one from a lower level master.
Comment: I have never done that and after now 43 tasks nothing.
Comment: Are you *sure* you don't have points? Have you actually checked the rewards screen at a slayer master? And this is 43 tasks *after* you completed the quest?
Comment: Yes 43 tasks after the quest and I have tried buying items at the slayer master but It says "This requires 15 Slayer Points to buy. You currently have 0".
Comment: I have no explanation for this.
Comment: @murgatroid99 After a recent update this answer is no longer valid.  Just figured it should be updated.  You no longer need to finish Smoking Kills to get slayer points. http://services.runescape.com/m=news/slayer-helmet-and-social-slayer-update
Answer: https://runescape.wiki/w/Slayer_reward_point

Slayer reward points are awarded when a player finishes an assignment or challenge assigned by any Slayer Master (except Turael/Spria). This ability is unlocked after completing the Smoking Kills quest. The higher level the Slayer Master, the more points are received. Slayer reward points can be traded in to any slayer master for various rewards. The approximate value is 943 coins per point (based on 35 points per batch of Slayer Dart runes)

https://runescape.wiki/w/Slayer/Challenges

Slayer challenges are unique challenges occasionally offered by each respective Slayer Masters to players coming to seek a new assignment. Each master's challenge is different and offers Slayer experience when completed, in addition to the regular slayer experience gained while killing the monsters in the task. For players who have completed Smoking Kills, completing a challenge for most masters also awards Slayer reward points, in addition to any slayer reward points normally gained for completing a slayer assignment. Turael/Spria, and Kuradal, however, do not award slayer reward points for completing their challenges. (When the challenge is finished, the chatbox lists on separate lines the rewards for the challenge itself and the rewards if any for completing an assignment.)
Players may decline the challenge without a slayer point penalty and accept a regular task instead. Declining will not permanently ban the opportunity to receive a challenge task; players may be assigned it again in the future.
Note: Slayer challenges do count as assignments, take this into account when you're nearly on your 10th and/or 50th task (for more points).
  Turael/Spria
  Turael or Spria asks the player to visit his or her new basement to slay all monsters there in one visit.
The monsters are:

Level 5 goblin (2)
Level 11 goblin (2)
Level 13 goblin (1)
Level 11 wolf (2)
Level 14 wolf (3)
Level 12 minotaur (5)

None of these monsters require any specialized equipment to defeat.
When done, the player is rewarded 1,000 Slayer experience for the challenge itself, in addition to any Slayer experience earned during the task.
Comment: This answer (or at least the first paragraph) seem to be entirely plagiarized from http://runescape.wikia.com/wiki/Slayer_reward_point. Please at least summarize the *relevant* parts of the source and cite it.

Runescape Slayer rewards?


Ergibt und ergibt sich

Question: I am under the impression that "ergibt" means "to give" or "results," in the sense of logical implication. I have seen it both by itself and with the word "sich."  I understand that "ergibt sich" means "giving one," in the sense that one now knows this result. But I do not understand what kind of situation calls for using "sich" versus not using "sich." Could someone please clearify this.
Comment: Note also: »sich ergeben« can also mean »surrender«: »Als die Polizei den Schützen stellt, **ergibt er sich.**« = »When the police put the rifleman, **he surrendered.**«
Comment: @HubertSchölnast Your translation mixes up times, and I'd use probably not "put" here.
Comment: @Robert Hubert probably meant to say "When the police cornered ..."
Answer: It depends on whether the result, in german das Ergebnis, is the object or the subject of the sentence.
If the sentence has the form "A ergibt B", then the result, here B, is the object.

Zwei plus drei ergibt fünf.
Two plus three results in/ amounts to/ yields five.

If the sentence has the form "A ergibt sich aus B", then the result, now A, is the subject.

Fünf ergibt sich aus zwei plus drei.
Five results from two plus three.
Answer: I try to explain it with an example:

[1] Die Beobachtung von Vögeln ergibt interessante Erkenntnisse.
[2] Aus der Beobachtung von Vögeln ergeben sich interessante Erkenntnisse.

In Sentence [1] »Die Beobachtung von Vögeln« is the subject and »interessante Erkenntnisse is the object«. In Sentence [2] »interessante Erkenntnisse« is the subject and the object.
Comment: I'll tell that to my wife next time she complains about me watching porn. SCNR. ;-P
Answer: You're wrong about "ergibt sich". The "sich" part does not mean "one", which would probably refer to the reader, but it means something like "results itself", which in German occasionally is the way to form what in English would be an intransitive verb. Compare:

I opened the door.
Ich öffnete die Tür.

But

The door opened.
Die Tür öffnete sich.

The same happens with "ergeben", as other answers have pointed out already:

Propositions A and B yield Proposition C.
Sätze A und B ergeben Satz C.

but

Satz C ergibt sich aus Sätzen A und B.
Proposition C follows from Propositions A and B.

Ergibt und ergibt sich


What software can change guitar backing track one-half step lower?

Question: What software can change guitar backing track one-half step lower? Many guitar songs are in E and A flat key and backing tracks are in pure E and A respectively, you know. It sounds obviously differently, especially when there is a vocal on record.
Comment: Are you willing to have a slightly slowed-down version of the backing track, or must the lower version be the same tempo as the original? Some methods of pitch shifting change tempo.
Comment: If you are using Cubase or Nuendo to record your guitar, there is a plugin called pitch shifter for you to do that.
Answer: Audacity is free, and can do this.
Import the audio file.  Highlight it.  click Effects > Pitch shift.  Select the amount (in semitones)
Done.
Comment: (Obviously a real full fledged DAW is better for detailed production work, but for a task this simple there is absolutely no reason not to just use audacity)
Answer: There are many products out there that can do this, ranging from the really simple "slow-downer" type applications that you can get free for every platform, up to professional products such as Melodyne.
As we aren't a software recommendation site, I'll leave it at that - a google search for pitch-shift will give you an almost endless list.
Answer: Transcribe! is such software. Works on Win/Mac/Linux. About $30 and has 1 month free trial. In addition to be able to change the pitch by half-step it can also change it by a percentage (which is useful for some old recordings that are not at A/440).
From the "slow-downers" - VLC player, which is also cross-platform and free, can do that (you have to configure it to actually change the pitch when changing speed).
Answer: Logic Studio is expensive but you can change keys on a recording EASILY. Doesnt matter if it's a guitar track, vocal track, or whatever.
Answer: If you want go half step lower you can do it with the help of windows mixer.
Firstly you need to right click the speaker icon in your task bar.
Then click on 'open volume mixer'.
Click on device speaker then.
Go to 'Enhancements' tab,
Select 'Pitch Shift'
Select -1 in the setting drop down menu.
If the track has vocals, it may sound a little funny, but it does the job.
Comment: Good tip, but it depends on sound card.  Some computers have this and others don't.  If you've got the realtek config panel open and you can't see it, it's probably because your soundcard doesn't have it.
Comment: Yeah right, but many computers may be having this feature nowadays.


Does flaxseed oil need to be refrigerated?

Question: I bought a bottle of organic flaxseed oil to season some cast iron, and the store keeps it in the refrigerator. Does flaxseed oil need to be refrigerated, or is this just a silly thing that the overpriced organic grocery stores do?
Answer: Flaxseed oil goes rancid quickly, and refrigeration slows down this process. So, yes, you should do as the label says (usually a good idea anyway) and keep it in the fridge.
Comment: The label doesn't say, actually, but it's in the fridge.
Comment: Will the life of flax seed oil be prolonged if it is stored in the freezer?


no fuel to carburater on new Kohler CH668 engine

Question: I installed brand new Kohler CH 668 in my mower. Motor does not start, fuel comes to carburator, but no fuel sprays into it. When pouring small amount of gas into carburator, it will run for a few seconds. tried to hold hand over carburator and after pouring gas and trottle at half speed with choke half open it will run on low speed for a minute or two. I know that it has solenoid shut-off, but then why would it run as described above?? I am lost?
Comment: Take a 1/2 inch wrench and tap gently on the carb, see if you can unstick the float.
Answer: It could very well be a solenoid shut-off or it could be that the float height is set incorrectly or the needle valve is jammed.


Is there a link between brain injuries (TBI) and PTSD?

Question: Could (TBI) Traumatic brain injuries be linked to Post Traumatic stress syndrome (PTSD)? I know there is a lot of concern with veterans and PTSD, but I am more interested in all the other situations/civilian cases of PTSD. From what I have read, there are overlapping symptoms between PTSD and TBI? Is it possible for someone to have PTSD from damage to the brain and not from a specific event?
Answer: It is reported that mild traumatic brain injury does not produce Post-Traumatic Stress Disorder however, according to this report in the American Journal of Psychiatry, severe TBI could possibly lead to PTSD in approximately 27% of cases.  In this study of 96 patients  (77 men and 19 women), after 6 months following hospital discharge for severe traumatic brain injury, 27% of them suffered PTSD.  Out of these patients:

19% reported having intrusive memories,
23% reported having nightmares,
31% reported having a sense of reliving the trauma,
65% reported avoidance of thoughts,
65% reported avoidance of places; and
73% had signs of hypervigilance.

However one point of note that the report detailed was that

First, our patients were not selected consecutively, and their
  responses may not be representative of populations with severe
  traumatic brain injury. Second, we did not obtain neuropsychological
  information on each patient.

I must admit that when I was looking at the report, due to the high number reliving the trauma and avoiding certain places, I wondered whether the trauma leading to PTSD was actually the brain injury or if it was the traumatic effect of the event which led to the brain injury.
Another point of note is that it was also reported in a committee hearing in the U. S. House of Representatives, that people with TBI are more likely to develop PTSD than those who have not incurred a brain injury
Personally, from looking at these reports, I think the jury may be still out on this one.
Comment: You are asking a different question here which will be of benefit if you post separately.  The idea of PTSD causing brain damage is different to the idea of TBI causing PTSD
Comment: Based on what I have read online and my own personal experiences; I keep coming across the idea that there might be some pathological occurrence that is directly related to PTSD. From a engineering student and neuroscience hobbyist perspective, it seems possible that emotions from a traumatic event could cause similar circuitry damage that is experienced from a brain injury. I figured I would throw my idea out there and see what people with more experience have to say about it. Thanks again for the info and insight!!
Comment: I might have worded my question wrong but I found an article that is along the lines of what I was thinking. http://neurosciencenews.com/tbi-genetics-brain-damage-6204


I need some help with this 15x15 nonogram

Question:
I have been working on this nonogram for some time and can't seen to figure out what to do next...
This is the link: https://nonograms-katana.com/play/#game
Comment: how come there are 2 pictures?
Answer: Look at the seventh column:

 With the X at the top of the column, you can completely fill out the rest of the column.
Answer: Row, 5 column 15 must be an X, which then yields additional deductions for column 15.
Answer:
In the fifth row,

 the rightmost $3$ can't start from the right-hand edge, because then it would become $4$ with the black cell you've already filled. So the rightmost cell in this row is empty (cross).

Then in the rightmost column,

 there's not enough space for the $6$ above the fifth row, so all those cells are empty. Now there's ten unknown cells to contain that $6$, so the middle two of them at least must be black. That enables you to cross off the rightmost $1$ in two rows.

In the fourth row,

 if the lone black cell in the middle is the $1$, then there must be $3$ to the left of it with an empty cell in between. Then, reading down from the columns, the three cells below that $3$ must be empty, but then the fifth row won't have enough space for its $3,1,3$. Contradiction, so the fourth row can be completely filled in up to the middle (two empty cells then two black cells).
Answer: Here's a couple of different places you can go from there, I'll leave the rest for you to solve:

Red squares are black, and grey squares are crosses, using colours to highlight.
Quick explanation:

The top most red must be filled in, regardless whether the other black to the right is part of the 1 or the 3. This greys out the square below, and means the red 3 can be placed as it cannot fit to the right. Furthermore, the bottom grey on the right cannot be filled, as that would make a 4, and from that some of the 6 can be placed.

Good luck! If you need a bit more I can add some


Upgrade bathroom light and separate exhaust fan

Question: I Have a small bathroom and it has a light that is separate from the exhaust fan. I want to upgrade it to a light and fan combo. Can this be done easily without having to go into the attic? I currently have the original exhaust fan from when the house was built in 1966. I already have three light switches in the bathroom.
Answer: Old school: probably not, unless the guy who wired that ceiling was generous with the wire.
Cool new tech: Yes.  They make electronic switch controls which are designed to solve a different problem:  "I want a light AND fan, but my bathroom is wired for a light only."   This consists of a smart switch that goes in the site of the regular switch, and an electronic control module that sits in the fan housing.
Now, I'm guessing your old fan has a vent - that is to say, a pipe leading from the top/back of the fan to the great outdoors. That will be a consideration.  Which is to say, if your fan/light combo is going where the fan was, that's not a worry.  But otherwise, you will need to be up in the attic reconfiguring that pipe... and while you're up there, you might as well rearrange the wiring to your preference also.
Answer: If you want to control the new fan and light separately you will have to do some re-wiring, and this may be difficult depending on where the existing light is. If you don't mind them coming on together then the wiring part is quite easy.
Whether you have to go in the attic depends on the fan you bought. Most do not install from below without hassle. Some, Panasonic in particular, do install from below quite easily. The venting is another issue, be sure to reconnect the vent and make sure it is not obstructed and vents to the outside.


ETH Smart Contract Confusion.

Question: What makes them such a big deal? Why not have an API to send and request money and then just use any language of your choice with said API to manage money?
Answer: Smart contracts are programs on the blockchain itself.
While it's definitely possible to create an API as you described, you have to trust that the program is running as the creator claims it does. In the same way, it's simple enough to create a monetary system in any language--but how do you trust it?
With a smart contract, every node verifies its execution, in the same way that every node verifies every monetary transaction. This means that, theoretically speaking, the operation of a smart contract cannot be interfered with by any party. This isn't infallible (see: bugs, hardforks, the DAO) but it's unique compared to the average off-chain program.
Comment: Why is trust such a big issue here? You ethier get the money you were expecting or you weren't and then the API is exposed. I'm just playing devils advocate here. Is trust the only thing smart contracts has going for it?
Comment: Suppose you want to lock up 100 ETH for a year, to be released under certain circumstances. (Some kind of insurance, for example.) If you can't trust that your wishes (in code) will be respected, how are you going to risk that 100 ETH?

ETH Smart Contract Confusion.


Why does my active low pass filter produce triangle waves?

Question: So here's what I'm trying to do:
Given a square wave provided by my arduino, use a nth order active low pass filter to modify the square wave into a sine wave by filtering out upper harmonics. This is in the audio range of frequencies, of course.
I've spent a good deal of time trying to do this and I'm pretty close to giving up and buying a function signal generator ic like XR-2206. I don't have any dough for fancy equipment, and may I stress that it's partly a learning exercise.
Maybe part of the problem being is I don't have an oscilloscope, and can't afford one, so oscilloscope is out. It would definitely help to have one, sometimes wishing I could see the signal I'm creating, but here's my thinking: If I can create an audio sine wave that I can hear, then I can change my RC values to work for higher frequencies. Right? (Or wrong?)
But I can never seem to get what sounds to me like a sine wave. I play back a youtube 1000Hz sine wave (or pick your frequency) and compare that to the output of my active RC filter and they just don't sound alike. When I listen to the 1000Hz triangle wave, then that sounds exactly like what I'm hearing from the output of my active RC low-pass filter. But why?
I've read over and over, all over the net and back, that by filtering out the upper harmonics of a square wave produces a sine wave (because of the details of Fourier Transform having an infinite sum of continually doubling frequencies with phase shifts and yada-yada) but the idea just doesn't seem to work. If I filtered out all the other sine waves and am left with the fundamental sine wave, then why doesn't it sound like one? Triangle waves!!!
I'm using n many resistors, n many capacitors, and n+1 many LM358 op-amps. I need the last one to amplify the output signal. I have read that many higher capacity capacitors (like electrolytic) are just too inaccurate for a proper low-pass filter in the audio range, so I'm using 100pF caps with very large value resistors. For example, if I used a 100pF capacitor with 1.62M ohm resistor, then the cut-off frequency is 1/(2*pi*100pF*1.62Mohm) = ~982 Ohms. By using multiple RC filters, you can create a steeper "roll-off" on the upper frequencies, and because the resistance values are so high, the signal needs to be amplified, which is why I'm using LM358 op-amps. The output of one active filter feeds into another, and is filtered again in the next active filter. I'm powering everything with 0 to 5V.
And I know the filter works!! I've modified my filter so that I can hear a crisp 400Hz (triangle??) wave, but by just increasing to 450Hz, the frequency is completely inaudible. Therefore, it's definitely filtering, and pretty damn well! Yet I can still not get a clean sine wave sound. Why? What am I doing wrong? Maybe I'll just torment myself further by trying to make a crystal ladder. Pretty sure I won't do that.
I am not expecting perfection. But I know what I'm hearing and it just ain't sine. Not even close. Any suggestions?
Thanks stack community.
Comment: Draw a schematic and consider using audactity on your PC as an oscilloscope for audio signals.
Comment: TL;DR, draw a diagram, try reducing the words by 70% to leave only the relevant ones.
Comment: You should be able to find an audio spectrum analyser for your phone too. This will show the relative strengths of the harmonics. For a symmetrical waveform you should only see odd harmonics.
Comment: The free program that @Andyaka mentioned is [Audacity](http://www.audacityteam.org/) (sorry to interfere, Andy, but the typo in your comment could really mislead the OP if he doesn't know the program).
Comment: Oops cheers @LorenzoDonati
Answer:
But I can never seem to get what sounds to me like a sine wave. I play
  back a youtube 1000Hz sine wave (or pick your frequency) and compare
  that to the output of my active RC filter and they just don't sound
  alike. When I listen to the 1000Hz triangle wave, then that sounds
  exactly like what I'm hearing from the output of my active RC low-pass
  filter. But why?

One thing to keep in mind is that even a small deviation from a sine wave will produce a sound very different from that of a sine wave. It very strongly depends on the harmonics that were not filtered out by your active filter circuit. You definitely need an oscilloscope.
The good news is, you can make an audio-frequency scope for peanuts:
http://www.instructables.com/id/Use-Your-Laptop-as-Oscilloscope/


Baofeng uv-5r,uv-82. i need disable or block side key moni(monitor) for don´t listen private cts dts

Question: I need to disable or block the side key moni(monitor) so others can't hear on my private CTS DTS.  I use a Baofeng UV-5R and a UV-82. Another team that uses the same repeater, but has different CTS DTS codes, can hear when I press the side key moni.
Comment: Related: [Receiving without configuring CTCSS](http://ham.stackexchange.com/q/5295/29) and [Can two FM radios transmit two separate PL tones at the same time, and be received by two radios with matching PL tones?](http://ham.stackexchange.com/q/1797/29)
Comment: Just don't press the button, then.  And always remember that everybody can still hear your transmit, whether or not you use any kind of tones.
Answer: Don't bother.
CTCSS tones are not an effective privacy mechanism. Anyone at all with a FM two-way radio or scanner can receive your transmissions; attempting to prevent this by locking down your radios gives you only the illusion of privacy.
(P.S. This site is for Amateur Radio, and I'm guessing you're actually a commercial radio user. I'm answering your question anyway because I think it's close enough to being about the technology in general and Baofeng radios are commonly used by amateur license holders as well.)
Comment: I totally agree with @Kevin, and would only add that the only way to disable it would be to take an X-acto knife and cut off the rubber part.  But then there goes any kind of water resistance.  So I echo:  Don't bother.
Answer: CTCSS tones or DTS digital tones, are only for "Receiving intended signals".
If a receiver is configured to receive on a frequency with CTCSS or DTS, then the squelch is only opening when the transmitted signal contains the "matching" CTCSS or DTS.
If a signal is transmitted without the "matching" CTCSS or DTS, then the receiver's squelch will not open, and you will not hear the signal.
However, if a receiver is configured on a frequency without CTCSS or DTS, then it will receive all signals, including those which have CTCSS or DTS, and the squelch will open.
So, if you are communicating on a frequency with many many users, you can transmit with CTCSS/DTS, and receive with the same CTCSS/DTS, and you will only hear these signals....
However, everyone else; with receivers configured without CTCSS/DTS... will also hear your transmitted signal!
This is why it is a "false/illusion of privacy" as answered already.
Use CTCSS/DTS only if you want to restrict a receiver to a specific transmitted signal, with the understanding that others can perfectly receive your signal.
HTH.


Why is "posts waiting review" figure always incorrect?

Question: Not sure where else to ask this, but the "posts awaiting review" figure in the toolbar is always incorrect for me. Often, it says I have three posts awaiting review, but when I go and look, there are none. Alternatively, it says I have 4, but there's only 1 ... most of the time it's out by 3. Any ideas? I know that it indicates it's an estimate (at least, that's what I assume from the ~ symbol), but I find it really odd that it thinks I have something to review when there is nothing.
Answer: When we rolled out the "pending reviews" indicator, we had to make an unfortunate concession to the fact that personalizing it for each user is too computationally expensive. The end result is that the number of pending reviews in the top bar is the total count of still active reviews in the system, including ones that are no longer available to you. (Plus some caching may be at play.)
We'd been thinking about ways to make this experience better, but I'm not sure what the status of that is right now. I'll raise it again internally.
Comment: Thanks Anna, appreciate the insight.
Answer: The number was made deliberately fuzzy a few months ago.  (Despite that post being on MSO, the change applied across the network, prompted in large part by problems on Stack Overflow.)  This was done to address a problem that smaller sites like ours don't seem to have, but I couldn't find any discussion of limiting the change to large sites.
So that's the "why", as best as I can tell.  (Though I don't know why it's usually offset by 3 in your experience.)  If you'd like to request accuracy in labeling on our site, you can make a feature-request either here or on MSE.  It'll be seen by SE in either place, but on MSE it might garner support from other small sites, or opposition from large sites.  Your call.
Comment: No, that change only applied to the close vote queue on SO. See my answer for an explanation of what's going on here.
Comment: @AnnaLear oh, thanks for clearing up my misimpression!  Craig, go with what Anna said; I'm wrong.


authentication on python for wsgi application

Question: I try to make simple wsgi application without any frameworks, only standard library (wsgiref). And now I looking for simple way to make authentication in my application. How I can make it?
Thanks.
Answer: I wrote a very simple authentication module here: https://github.com/comamitc/py-userauth
It should give you some ideas to work on if you want to write your own to handle encryption of the password, password matching, complexity checking, registration, etc.
I would also check out Django's authentication mechanism as it's pretty widely accepted and really fleshed out.
Unfortunately, my example doesn't contain any wsgi specific code, but just some general guidelines to setting up your own authentication.
Answer: If you are not going to use any frameworks or libraries, you just have to implement it manually: use some kind of storage for credentials, generate forms, check passwords preferrably using salted hashes, create and store session identifiers in cookies and so on.
But maybe if it's not intended to be a public application, you can go with just basic HTTP auth implemented in Apache, nginx or any other web server you are using to launch your wsgi app.


Why is AT&T's stock price declining, during the days that they announced the acquisition of Time Warner inc.?

Question: Why does the stock price decline when a seemingly promising acquisition is announced & agreed on?
Comment: Nobody has any clue, at all, why stock prices go up or down.
Comment: @JoeTaxpayer Excuse me, but the site describes itself as a site for those "who want to be financially literate". This question seems to be a good fit, but how can I know in advance that this question is primarily opinion based if don't know about stock market dynamics? I don't know anything about stock markets, and this question feels like it can be answered objectively by explaining some kind of dynamic, but I wouldn't know about whether this statement is true. I'm sure if I asked "Why don't prices rise if a product sells less to compensate for a loss of profit" it wouldn't be opinion based.
Comment: Welcome to Money.SE. Please [take the tour](http://money.stackexchange.com/tour) to see how the site works and what questions are on topic here. This question is likely to be closed as opinion, although it may be possible to reword it to be more general.
Comment: @DanielAnderson no, Joe Blow is correct. Correlation does not imply causation, and sometimes stock prices move completely contrary to what a reasonable narrative would suggest.
Comment: @Hay - typically, questions about particular stocks are off topic, both as matter of opinion, and for the fact that such a question is time-sensitive. What I tried to imply to the OP was that the question, if closed (which it seems not) could be worded generically, avoiding the mention of a particular stock. Else, this question might be repeated every time there's a takeover announcement and either stock drops. Thank you for your concern.
Comment: @DanielAnderson Mere correlation does not imply causation at all, ever, period. This is drilled into every statistician's head. There's a strong correlation between my weight and the Earth's mean temperature. There's a strong correlation between the number of churches in a town and the number of rapes per year. Neither of these things even imply causation.
Comment: In average acquirer's stock price declines and acquiree's price goes down after the acquisitions.
Comment: @JoeBlow [Obligatory XKCD](https://xkcd.com/904/). ;)
Comment: @DanielAnderson You are inferring that which is not implied because the human brain has evolved to notice patterns and assign meaning to them in order to survive. Correlation does not imply causation. I got out of bed today and the stock market rose. This in no way implies that my getting out of bed caused the stock market to rise. Your quote from Wikipedia lists a connection, not an implication, and is working in the *opposite* direction (causation does imply a correlation by definition)
Answer: It is not unusual for the acquiring company's stock to fall in any time of merger announcement.  Some of it has to do with the fact the acquirer is going to either take on new debt to pay for the cost of the acquisition or they will need to issue new shares.  Either is dilutive to shareholder value, so this is "baked into" the process.
In the instant case, I'm not sure AT & T is making the right move.  Because of its acquisition of DirecTV several years ago, there's little question it will have to shed assets in order to satisfy regulators, and there's a high probability that competitors will move to block the merger for obvious reasons.  There is also the distinct possibility that regulators (either U.S. or European) may block the merger altogether, in which case there's undoubtedly a provision in the merger agreement requiring AT & T to pay a substantial fee to Time Warner.
There's a great deal of uncertainty surrounding acquisitions like this.  After all, it wasn't helpful to Time Warner when it merged with AOL, and there's no assurance this merger will work out any better.
The long and short of it is that nobody knows how this merger will play out, and the amount of attention and resources necessary to complete it will be an enormous drain and distraction to AT & T, so there's the possibility its businesses may suffer somewhat.  Since nobody knows the extent of divestitures AT & T will have to make, it creates uncertainty.
This is what you're seeing in their stock price.
Comment: And what investors dislike the most is uncertainty.
Comment: *"...its acquisition of DirecTV several years ago...."*  Um, you mean that acquisition that officially concluded in July 2015?  (And it only *started* in May 2014, though I guess [two years does qualify as "several."](https://xkcd.com/1070/))
Comment: @Scott if they issue stock, it will almost certainly be at a discount to the market, and therefore cause the price of outstanding shares to fall - in which case it is no longer a $1.5 billion company. If they issue debt it won't be directly dilutive but the interest payments will be costly, again eroding market capital and hence share price.
Comment: Is issuing new shares and using the money raised to buy a business actually dilutive?

Surely you just go from 0.00000015% of a billion dollar company to 0.0000001% of a 1.5 billion dollar company?

I don't think it matters whether the company is buying up the other with cash, debt, or stock issuing.
Comment: @Scott, the reason new stock issues are dilutive is because it puts more supply into a market that may not have any additional demand.  This causes the value of all the stock to decline, thereby diluting the value of shares held by shareholders prior to the issuance.  Taking on debt is dilutive because debt servicing costs reduce net earnings, thereby reducing EPS.  Debt may also inhibit a company's ability to pay dividends, which further erodes shareholder value.
Comment: @chili555 In university a friend was on an investment competition and his team won. A team from another university actually made more money than my friend, but because my friend's team had a better return compared to risk. They train finance majors early that risk is the worst thing you can have in a company.
Comment: This is what really confuses me.  Why does everyone keep trying to buy TWC?  AOL did it and basically broke the economy for a few years, Comcast tried to do it and was blocked, and now it's AT&T's turn.  What's going on?
Answer: Markets are generally skeptical of the benefits of mergers.  History shows that the benefits of merger claimed by the company doing the purchase rarely materialise.
If on the day prior to the announcement the markets value company A as 50 billion and company B as 20 billion, then the market values the combined company at 50 + 20 = 70 billion if they see no benefit in merger.
Therefore, if company A is willing to pay a premium of, say, 5 billion for company B, then the market will mark down company A by about the same amount in order to maintain a combined value of 70 billion.
Of course this assumes that the markets see no real benefit in merging the two companies.  This is not always the case.
Answer: Typically, stocks are falling because more people try to sell than to buy. Why they try to sell is anyone's guess.
In this case, it seems that not everybody shares your optimism; you might not have all the info, or you are evaluating the data differently than others.
Answer: "Buy the rumor, sell the news". That's often a good strategy, since most people tend to be optimists rather than pessimists, and reality turns out to be worse than they hoped for.
It's also a good strategy, because if the majority of other investors think it's a good strategy, the price will rise when they all try to buy, and fall when they all try to sell.
Answer: It's a material change to the company's financials, why wouldn't there be a change in the company's value?
In general the company being acquired sees a value increase.  This happens for a variety of reasons, most obviously the concept that a premium on the value will ensure shareholder approval of the acquisition.
In general the company making the acquisition sees a decline in value.  This happens because of a usually material change in the financials.  Maybe a big spend down of cash, maybe a big issuance of new shares, maybe a new debt obligation, maybe the company being acquired has new liabilities etc.  Usually companies are valued based on some multiple of forward earnings and a big change in the financial situation of the company will change it's forward net earnings.


Is a marriage valid without providing prior divorce papers?

Question: A Muslim lady who was a divorcee married a man without providing her previous divorce papers. Is her marriage OK?
Comment: Did she inform him before he married her that she was a divorcee? Other than that papers are just government formalities.
Comment: In Islamic Jurisprudence you don't need papers to validate your divorce. Both the ex-husband and the husband-to-be have to know that the woman is divorced. Paper work is important if you want to handle things properly, specially related to their property.
Comment: is ir nesassary to give divorce paper  to qazi  at her second nikah
Comment: If papers are not needed, why should it be necessary to show them a qadi? The point that makes divorce take place is simply speaking the end of the 'idah (waiting period) without a reconciliation. Else a marriage would be invalid. This is covered in the given answer.
Answer: Some cultures and countries insist on 'paper work'. But like @Noah and @System Down have sated, they are only formalities.
However, whether paper work is there or not, the following need to be done.

She must be officially divorced (not pending).
Shem must have completed her waiting period (Iddah). No marriage is possible without that.


Why is the circulation around a centrifugal impeller blade tip the opposite to a wing tip?

Question: Why does the circulation around a centrifugal pump blade tip go from low pressure to high pressure as an effect of the slip caused by the non-uniform velocity distribution (the opposite of a wing tip). The reason stated in my book says that below the blade there is low pressure leading to high velocity and vice versa for the part above the blade. In an airplane, there is vortex at wing ends where air moves from below(high pressure) to above(low pressure) as given in the diagram.
Comment: Deepak, your second picture depicts wing tip circulation, which may be a different consideration from evaluation of 2D "circulation" of an airfoil.
Comment: Also how less pressure leads to high velocity? Don't tell me to use bernoulli as the flow has vorticity.
Answer: I think what's confusing you is that the text book is using the term circulation to describe speed relative to the average airflow, not actual circulation around the blade.
There's still a black arrow pointing outwards on the high pressure side of the blade - no air is travelling inwards.
However if you look at the difference between actual speed and the average speed, it's negative on the high pressure side and positive on the low pressure side.
I don't fully understand the theory, but I think you're supposed to imagine the surface of the aerofoil (or an infinitely thin layer of air next to it) to be circulating, and causing the velocity gradients.
Wikipedia says:
Circulation is often used in computational fluid dynamics as an intermediate variable to calculate forces on an airfoil or other body.
Comment: I think you do understand it fairly well.  Look a nor'easter compared with a hurricane.  The circulation in a hurricane is perfectly circular.  The faster moving nor'easter has air flowing "up" and over the "top" of it, and a "downwash" behind it.
Answer: It is important to visualize the flow into this pump is on an axis perpendicular to the plane of the diagram, flowing towards it.  The pump spins "clockwise", there for higher pressure will be on the right side of the blades.
But the centrifugal pump, true to its name, adds energy to the fluid by its rotation, which slings the fluid to the right.  The "centrifugal force", really the fluid being propelled to the right 90 degrees from its in flow, drives it at much higher velocity towards the outside of the impeller.
The circulation circled in the diagram seems to be a minor part of the total flow.  Though there may be some, the majority of the inflow will be driven towards the outside of the impeller as new fluid is drawn in.
Centrifugal compressor designs are seen in early jets, and are still seen in R/C model jets.
Upon futher inspection, look closely, the circulation is the SAME as a wing.  Because the wing is in motion, the circulation may not be fully closed, but the lower pressure areas created by the airfoil as it passes through the air imparts energy to the air in a similar manner as the pump (top lift), as well as the higher pressure area underneath the wing (bottom lift).
The impeller blades are curved oppositely as what we may expect to see in a "wing". Keep in mind this is a rotating device.  The outer part of the impeller blade moves much faster.


Why is alcohol so expensive in Australia?

Question: How is it that alcohol is so expensive in Australia? Is it just because of taxation?
Comment: You can buy Aussie wine in the U.K. for the same or less than in Australia.....something wrong there!
Comment: Do you think the government lowers the excise on exports so they can make money from selling it overseas in terms of share volume that can be sold overseas
Comment: I believe there is a 3 tier tax system in Australia, state, national and VAT (or equivalent) that keeps the price high. As far as export goes it's the same in a lot of places. You can buy Scotch cheaper in Oz or Spain etc than you can in Scotland. It's the international trade scam 'sell us your thing cheaper than you sell it at home and we'll do the same'.
Answer: Why is alcohol so expensive in Australia?
It is mostly due to taxation. But not all of it is.

The World Health Organisation's latest Global Alcohol Report put Australia in the second-highest band of alcohol consumption: total per capita consumption is between 10 and 12.4 litres of pure alcohol a year.
According to the Australian Hotels Association, around 20 per cent of the cost of beer at the pub is made up of tax.
INCOHERENT SYSTEM
Regardless of whether you think we pay too much or too little, Australia's current alcohol taxation system is, put simply, a complete mess.
It's a hodge podge cobbled together over 30 years of deals, dodges and industry favours.
Case in point: commercially produced beer today is taxed at no fewer than eight different rates, depending on a range of factors including alcohol volume and the type of packaging.
Meanwhile, wine is taxed not on alcohol content but sales value, meaning the cheaper the wine, the less it is taxed.
At the moment, there are broadly three different federal taxes that apply to alcohol:
• Excise, indexed twice annually in line with the Consumer Price Index
• The Wine Equalisation Tax (WET), which is based on sales value
• Customs duties — a combination of alcohol content and sales value
There is also the flat 10 per cent GST on all retail alcohol sales.
The automatic indexation was introduced by the Hawke Government 30 years ago as a way of avoiding negative headlines every budget.
At current taxation levels, drinkers pay 45c for every 1 standard drink in a full-strength beer. For spirits, which are taxed the highest, it's an extra $1 per standard drink — a mark it hit for the first time this August. - Why do we pay so much for alcohol?

To this one can add the production price, distribution prices, markup prices at alcohol outlet stores and import costs when applicable (transportation and import duties).


OR/AND in Google Drive search terms?

Question: I can imagine situations where it would be really nice to be able to use complex conditions on Google Drive searches. Is it possible to OR and AND search terms?
Right now, I'd like to search on Google Drive for a document with several possible owners. I have a personal Google account as well as on for work and I sometimes create a document using the "wrong" account. When I do this share the document with my alter ego. However, this means that I can't do a simple search using owner because my "other self" might be the owner.
So, I'd like to be able to do something like this:
owner:email@example.com OR owner:email@example.com
Is this possible?
Answer: Instead of
owner:firstname.lastname@example.com OR owner:firstname.lastname@example.com

use
owner:(email@example.comfirstname.lastname@example.com)

OR/AND in Google Drive search terms?


What do we gain from hashing the length in Merkle–Damgård?

Question: Assuming our fixed compression function $h$ works for inputs of length $i(n)$ and output strings of length $o(n)$, if $2o(n) < i(n)$, why do we need to calculate $h(z_B||L)$ where L is the input's length instead of just concatenating $z_B ||L$? What do we gain from hashing the length?
Answer: I am making the assumption you are asking why not just append the length to the output of the hash, the question is not quite clear on that. Take a very simple example of SHA-1 modified to do what I think you are asking. The results here are fake, but the example stands.
If we hash a byte stream of 0xFE25B6A1C8, we may receive the digest a9993e364706816aba3e25717850c26c9cd0d89d0000000000000028.
If we hash a byte stream of 0xFE25B6A1C800, we may receive the digest a9993e364706816aba3e25717850c26c9cd0d89d0000000000000030.
It should be clear that this is not a desirable property.
The same property applies to other inputs where there are trailing 0 bits within the same compression function call and the same total number of compression calls, the bits have no effect on the hash function without the length because of how they are used to generate the message word array.
Comment: Deterministic bit padding would make this answer incorrect (currently there is only padding when required *because of the length* but that's easily fixed).
Comment: Rereading that last comment: it should be preceded with "Note that" as it doesn't invalidate the answer; I've actually voted up this answer in Januari '17.
Answer: Well, there are two immediate reasons, besides the points given by the answer linked to by CodesInChaos about the harder security proof:

the size of the hash value would grow by 64 bits to encode the length;
the size of the message would be directly leaked.

The second property is not good at all; think of hashing passwords, or even hashing a message using HMAC while the size of the input is always leaked. That would certainly leak information that you do not want to be leaked.
Answer: From theoretical point of view, we CAN, if the underlying hash is collision resistant than using the modified version you suggested would create collision resistant hash, BUT, the size of the output will grow, instead of size $o(n)$ we would get output of size $o(n)+i(n)$. Note that hash function does not need to hide anything, it just needs to have the collision resistance property.


Maxima 02 gear stuck in neutral

Question: My manual transmission is stuck  on neutral I was driving on freeway when I exit and took out of 6th gear it would not go into any gear no noises does it make just wount go into any gear not even reverse. Any suggestions on what I can do my self before taking to shop? I appreciate any help.  Thank you
Comment: Welcome to the site. Is this a manual transmission?
Comment: Yes it is manual
Comment: Haha, I guess I could have just read the post ... sorry about that, lol.
Answer: There are usually three possible things that I know of that prevent shifting between gears other than internal transmission problems. Hydraulic clutch master or slave cylinder issue or a bad clutch or God forbid all three at the same time.
Comment: Thank you for that. See I had the all those 3 parts replaced 3 months ago.  The clutch feels normal has pressure.
Comment: I remember before it gave out  while going into 6th gear it felt different than all other gears. It felt as if it was forcing to go in not smooth felt as if it was rubbing against both sides gearbox? And when going out of gear same difficult to take out of gear and felt as if it would go into 5th gear at times it would and I would go to neutral from 5th

Maxima 02 gear stuck in neutral


Sanding between coats of water-based finish

Question: I built a farmhouse table with Douglas Fir, applied Saman water-based stain, and then applied the first coat of water-ased finish. The folks at the store said I should sand after the first coat, using at least 220 grit sandpaper, which I did, using my random orbital sander. But the sanded surface is now full of milky white scratches, and in a couple of smaller patches the stain came off. What did I do wrong? Should i not have sanded, or did I sand too hard or should I have used a finer grit? Finally, do I need to start all over again and re-stain the table?
Comment: Stain should soak in...you shouldn't be able to sand it off unless you actually remove some of the material you're staining. It would be helpful if you could improve your question, by saying _exactly_ what product you've used, and providing photos of the post-sanding condition that you're asking about. I've never sanded after using a product that is strictly a stain; but maybe you're using a two-in-one finish, with stain and surface coat. Light sanding is all that's needed...I wouldn't use a power sander, and if I did I'd make sure I used a very light touch.
Answer: sanding between coats should just be a light rub, usually it's less effort to use a hand block, or a sanding sponge than to lift a power tool,  you only need to remove the sheen, when the paint looks mostly dull that's enough rubbing.
Water based finishes can take considerable time to set, especially during cold or humid weather.  If you ignored the makers advice for suitable painting conditions you will have to wait longer than the label suggests for the paint to be hard enough to sand.


How do I water my two apple trees?

Question: I have two apple trees. I have lived here for three years and I am sure they are a couple of years older than that. They are both producing fruit but I do not know how to water them. Do I put a ring in the dirt around them about ten inches from the base and soak them once in a while, or do I just water the ground. How often do I water them. And how do I prevent the little pin hole size bad spots on the fruit? I live in northern California just above Sonora at about 3000 feet.
Comment: I'd ask about the spots on the fruit as a separate question. It's more likely to get attention and better answers.
Answer: I didn't need to water any of my fruit trees regularly in Ontario, but when they were new the advice I was given was to get a large bucket and put a small hole in the bottom, then put the bucket near the base of the tree and fill it with water. This would release water into the ground slowly enough that it could soak in rather than running off.
If your trees are looking healthy and the leaves are not wilting, they are unlikely to need watering. If you are having a drought, this technique will probably work. You could also put on a sprinkler near them so their root area (which typically mirrors their branch area) is getting water.
Answer: I'm in zone 7A and get around 43 inches of rainfall a year.  Not all that different from where you are.  Other than when my trees were young - first year or so - I've only given them water when we hadn't had rain for more than 10 days or so.  The roots tend to grow pretty far down (ask me how I know!) and are able to extract water from the soil quite well.  I honestly don't think you need to generally do supplemental watering unless you're in drought conditions.
You might find some useful info here on spots on apples.  I'd bookmarked it a few years ago when I was trying to diagnose a problem I was having.
Answer: Five (or more) year old fruit trees shouldn't need supplemental water if you get enough rain. If you are experiencing a drought, you should water deeply and infrequently. E.g. the bucket-drip method that Kate Gregory mentions, every other week, making sure that you use plenty of water so that it gets deep to the roots.
Frequent watering with small amounts will encourage the tree to form shallow roots, and without deep roots it will be unable to secure its own water from deep in the soil.
I get about 40-45" of rainfall annually, and except for the first year I don't irrigate on a regular basis. Last year during the drought I gave each tree 2 x 5g pails of water every other week. (Bathtub water works well for this.)

How do I water my two apple trees?


Distance covered in Premier League

Question: Where can I find the distance covered by players in the Premier League and the other 5 big leagues? I know you can find the ones for the Champions League on UEFA's site but I can't seem to find it for these leagues.
Answer: The distance covered by players can be calculated from the data via the performance data feeds provided by Opta, however these are commercial and would require some form of payment to access them.

Distance covered in Premier League


Display attachment as image rather than link in custom list form

Question: I am making a custom list form where the user will input texts and can upload images as attachments. This images will serve as an icon next to the inputted text in the allitems.aspx. How can I make the attachment be viewable as image rather than a link? Any inputs will be much appreciated.
Answer: I had similar situation, but for me it was one time activity. Will go ahead and give solution

Once we had image attachment in sharepoint list, we opened all those attachment in explorer view and stored them in Picture library.
Also created custom column of type Hyperlink and selected type picture in a original list. Updated thumbnail URL for each item from respective image from picture library.
Finally we get that thumbnail against each item. Use of picture library is to have thumbnail size images of attachments.
Answer: If you are using SharePoint 2013 farm and want to customize the default list forms (Display/New/Edit forms), you can use Client Side Rendering (CSR). It allows you to define your custom rendering in javascript.
There is a nice article on MSDN regarding CSR implementation. Kindly follow along.
MSDN article on CSR


What kind of medicine would you pack for a 7yrs old first flight?

Question: I mean the flight itself. We have something against nausea (Daedalon) and I am trying to find something for a stuffy nose but since I am more Canadian now than Hungarian I have some difficulty figuring this out. Any good tips?
Comment: None, unless the child has a medical condition that requires some? What exactly are you trying to treat?
Comment: Ask your doctor, what he recommends.
Comment: @CMaster: I don't know about you, but when I travel, I bring along various common over-the-counter medications (ibuprofen, Pepto-Bismol, cortisone cream, etc) to treat various common conditions that I may not have now, but may arise unexpectedly (headache, indigestion, insect bite, etc).  Wouldn't it be reasonable to have an analogous list for a child?
Answer: You are better off asking a doctor this.
A child often needs medication labelled for children and it's important you do not give him an adult dosage.
Does your child have the flu? Or are you trying to pack medication 'just in case'? If he has a runny nose I would recommend a simple salt based nose spray, if he has no complications at all and you are just trying to prepare, don't bother.
Comment: @chx it's not clear what you are trying to prepare for though. Healthy humans don't spontaneously need medical care mid flight, even young ones. Equalizing ear air pressure is normally one of the most difficult things for children, but that doesn't need medication either.
Comment: +1 for if he has no complications, don't bother.
Comment: Do not use travel sickness medication unless he is prone to travel sickness and has good reactions on the medication. (I was always car sick, but much worse when given medication.) Flying it a different kind of motion, very gentle, it is very likely he does not need motion sickness medication at all.
Comment: I am just trying to prepare. And I can read the product labels fine, I still speak Hungarian, I lived here for thirty years (alas).
Answer: Our four year old has two long haul trips under her belt (SE Asia to Africa, SE Asia to America).  We don't take anything different for the flights than we take for a road trip.
She gets a little anti-nausea medicine before the flight (because as an infant she got car sick) and that's it. But we have been cutting that dose down each trip, come March when we fly to the states we will try without.
I don't give her any congestion medicine unless she was suffering from a head cold.
But for your child, a discussion with your family doctor is the best course of action, as your physician knows the child's weaknesses and strengths when it comes to health.
Comment: Good on cutting down the travel sickness medication. Many children grow over their travel sickness. Just remember that any illness may give a temporary setback on growing out. (I still get sick a couple of weeks after a flu while grown out of normal travel sickness at about 16.)


Allowing Flash Player even though its insecure

Question: Sorry but since "add a comment" only brought up a sign-up-window this will be a new question.
It is again about allowing flash content to be played within the TOR-Browser. Every one just answers it would be insecure and thus is blocked even if the plugin is enabled and the player installed. Flash may leak the IP-Adress.. to whom? The flash site itself might get to know who I am, but the provider of the internet I'm using will not. And that is still some kind of anonymity wished for as long as flash is still around.
So one answer is 'go VPN instead'. But why do you want to kick out flash users from the TOR-Community? The whole idea was to get lots of people using TOR for normal reasons so that whistleblowers for example can hide in that crowd. And what is a more normal use of internet/TOR than browsing for porn? As long as the NSA-Buildings we all got to see in the Snowden-News are not hosting a majority of all porn content to get the real identity of TOR-Users that porn surfing crowd is helping to hide other more critical guys.
I do think blocking flash is a terrible decision. Warning about Flash is enough. Also No-Script can be just deactivated allowing Java-Scripts leaking the IP adress and no one is blocking that. It just works the way flash used to work in TOR.
Just allow everything every normal web browsing user would expect to work. And allow to go back to full-safe-mode with one click. And that's it. Security for the ones who require it, Comfortability for the crowd protecting that kind of dudes and porn for the ones takeing a break from being full secure without haveing to rely on another product (VPN).
Answer:
Flash may leak the IP-Address... to whom?

To whoever you're trying to hide from in the first place. The website will load through Tor, but Flash Player does not obey proxy rules, and will make a direct connection to the website.
Once Flash Player makes a direct connection to the website, it doesn't matter if you're using Tor. Your ISP, the website owners, and even someone on the same Wi-Fi network can see the direct connection from Flash Player, and figure out what website you're going to, and possibly see what you're watching in Flash Player.
Alas, since this is a question-and-answer website, there is a way to use Flash Player through Tor. With the Tor Browser open, go to your personal browser, and change the proxy settings to use a SOCKS5 proxy at 127.0.0.1:9150.
Alternatively, with a little more configuration, you can install tor and configure it to only run as a local proxy.


Back reference in Wikipedia

Question: Say an entry A has a cross-reference pointing to entry B. Is there any chance that given entry B, we can know it is referred by entry A (any probably other entries)?
Answer: I'm assuming you're talking about internal links between Wikipedia articles, known as "Wikilinks" or "internal links". You can see which articles link to a specific article by using the "What links here" tool. On desktop, there's a link to this tool in the left sidebar, in the "tools" section. I wasn't able to find an easy way to access the tool from an article if you're using the mobile version of Wikipedia, but the tool is available here.
If I was wrong to assume you meant internal links, and instead you meant links to Wikipedia articles used as references in other articles: that shouldn't happen, because Wikipedia is not a reliable source, and thus shouldn't be used as a reference in other Wikipedia articles.

Back reference in Wikipedia


Apple's wired keyboard (with adapter) doesn't work on MacBook Pro 2019

Question: I just switched from my old MacBook Pro (2011) to the newest one. Because I'm often working with a display I've been using Apple's wired keyboard from 2007 (A1243).
While it still works on my old MacBook, it somehow doesn't work on my new one. The keyboard does seem to be somewhat connected since it sometimes (rarely) reacts (although with a lot of lagging) when I press a key repeatedly on the keyboard, even though the light of the caps lock key isn't working either (when I press it).
But there was one time the keyboard worked perfectly fine. It stopped though when I disconnected and then reconnected it.
The adapter doesn't seem to be the cause of it since it doesn't show any problems with connecting to other USB cables (for my iPhone, iPad and an external hard drive or even my mouse).
Is this problem solvable or do I need a new keyboard?
Comment: How is the keyboard connected to the computer?  Does the keyboard show up in System Information? https://support.apple.com/en-us/HT203001
Comment: Yes, the keyboard shows up there.
Answer: Resetting the System Management Controller on my MacBook seems to have solved this problem.


Does loving kindness meditation help beings other than the practitioner?

Question: For an example when the practitioner wants every being to become free from sorrow, does it actually create a difference? At least when the practitioner concentrates on someone close to himself/herself. All answers are welcome and it's better if references from Pali Canon can be made.
Answer: I don't think it'd make other beings become "free" from sorrow, but it could bring certain level of peace to both the practitioner and the people s/he's interacting with. AN 11.16 mentions 11 benefits of cultivating metta:

"Monks, for one whose awareness-release through good will is cultivated, developed, pursued, handed the reins and taken as a basis, given a grounding, steadied, consolidated, and well-undertaken, eleven benefits can be expected. Which eleven?
"One sleeps easily, wakes easily, dreams no evil dreams. One is dear to human beings, dear to non-human beings. The devas protect one. Neither fire, poison, nor weapons can touch one. One's mind gains concentration quickly. One's complexion is bright. One dies unconfused and — if penetrating no higher — is headed for the Brahma worlds."
Answer: I don't know of a sutta that suggests that prayers or concentration directly affects the well being of beings being prayed to or concentrated on.
Quite the contrary, suttas like the one below suggests that such thing would be wishful thinking. That is, wishing someone to be free from sorrow as the method to make them free from sorrow is a fruitless method.

"Suppose, bhikkhus there was a hen with eight, ten, or twelve eggs that she had not covered, incubated, and nurtured properly. Even though such a wish as this might arise in her: 'Oh, that my chicks might pierce their shells with the points of their claws and beaks and hatch safely!' yet the chicks are incapable of piercing their shells with the points of their claws and beaks and hatching safely. For what reason? Because that hen with eight, ten, or twelve eggs had not covered, incubated, and nurtured them properly.
"So too, bhikkhus, when a bhikkhu does not dwell devoted to development, even though such a wish as this might arise in him: 'Oh, that my mind might be liberated from the taints by nonclinging! ' yet his mind is not liberated from the taints by nonclinging. For what reason? It should be said: because of nondevelopment. Because of not developing what? Because of not developing … the Noble Eightfold Path.
-- SN 22.101
Comment: Actually my question was meant to sorrow, pain,illness in regular life. Not about sorrow arising from clinging. It's quite clear no one can make anyone else's mind get liberated.


1.Error Message "Failed to Fetch Updates" 2. Negative Terminal Response to sudo apt-add-repository

Question: Only had E.OS 5.1 Hera a few days and have encountered 2 issues which I cannot resolve and can be best explained by the two uploaded screenshots. The 1st - this dialog appears whenever I open the app repository and only started to appear after I downloaded via terminal the repositories required for flatpak and sideloading. At the same time I installed FreeFileSync from the online flathub repository.The dialog mentions the possibility of manually downloaded repos as being a possible cause but would like to check with other users. The 2nd - I am endeavouring to install the repos necessary for the installation of Timeshift and have been following a procedure shown in an online tutorial. Despite having used the precise same syntax as the tutorial shows the response is as shown. I would truly appreciate any assistance that any one can offer. Many thanks - Bob Deb
Answer: Your first issue appears to be an issue connecting to the Ubuntu archives at au.archive.ubuntu.com.
If that's the issue perhaps its temporary.
I can connect to the server just fine.
In case it is related to other repositories configured, can you run the following command from a terminal and show the output.
This will show your system's configured repositories.
grep -r --include '*.list' '^deb ' /etc/apt/sources.list /etc/apt/sources.list.d/

For your second problem, the command add-apt-repository is provided by the software-properties-common package so you just need to install that.
sudo apt -y install software-properties-common

Comment: Looks like I am breaking protocol here by sincerely thanking you for 1. Connection to the server has been re-established without any further action by me.  2. Installing software-properties-common has enabled me to successfully install Timeshift. This has been my first post and I am totally unfamiliar with the associated protocols but I can see that there is some sort of voting procedure involved. I will be endeavouring to award your answer maximum points possible but, if through procedural ignorance on my part that doesn't materialise, you can rest assured I am extremely indebted to you.
Comment: Sorry to be a nuisance, but I am unable to find the procedure for logging off from stack exchange. I expected to click on my avatar and select "Log Out" from a drop down menu but this is not the case. I have tried every other conceivable method but without success. Could some kind person steer me in the right direction? Many thanks - Bob Deb.
Comment: You're not a nuisance and you're welcome  You should be able to mark an answer as your selected answer, but no worries about that. What's funny is I couldn't find the log out button either. I've never tried to logout before now. It's hidden under the hamburger menu in the top right corner. Just click that button and a _log out_ button should appear. Cheers!
Comment: Found him! Once again many thanks.


What happens when The Hulk goes into space?

Question: In Hulk (2003) when the fighter jet, takes Hulk to the "top of the world" (an altitude of over 95000 feet, and into the beginnings of space, what actually happens to Hulk? He is seen suffocating, his green sheen wears off and he finally collapses mid-way but what is actually happening to him?
Comment: I thought the sheen was him freezing rather than changing.
Comment: @Richard as was so aptly demonstrated by the *Green Lantern* movie!
Comment: Did you know: The max altitude of the F-22 _(which is the fighter jet in question)_ is currently 50,000 feet. To see 'space', an aircraft must reach a height of 90,000 feet.
Comment: @daft - **actual** max or max **safe** altitude? Note that there may be a difference of 20,000 or more feet between those two figures.
Comment: When Hulk was actually shot into space in the comics, he returned as a warlord commanding underlings almost as strong as him. He basically took control of earth until the Sentry stops him. See the comic series Planet Hulk and World War Hulk..
Answer: In reference to the movie, the official novelisation would suggest that he passed out due to a lack of oxygen:

The strategy, developed on the fly, in every sense of the word, by
  Thunderbolt Ross, was devastatingly simple: Take the Hulk on a ride to
  the top of the world, and see what some thin air did for him.
The Hulk clung to the plane as it rose up through the clouds. Frost
  began to cover him, hanging from his hair, his eyebrows. The world
  started to fade around him. Close to losing consciousness, he stared
  into the eyes of the pilot through the cockpit's windshield. The pilot
  flinched, concerned that the Hulk would abruptly recover and try to
  tear the wings off his plane. But he needn't have worried, for the
  Hulk closed his eyes completely, and as the plane tilted back—having
  gone as high as it could safely go—the monster slid off.

Note that although the Hulk is able to hold his breath for a considerable amount of time, he doesn't seem to be able to cope with hypoxia...

But all the Angry Man did was glance up disdainfully at the
  helicopter, and then he took a deep breath and went under again.
Ross remembered the Hulk's ability to survive on a single breath from
  the encounter with the gas. The situation wasn't promising, and Ross
  was beginning to realize that this wasn't simply a case of man against
  man. This was man against a force of nature . . . and unfortunately,
  in such conflicts, man always came up on the losing end.
Answer: Hulk needs to breath, although he's extraordinarily able to keep his breath during long periods of time.
On the event of suffocation, usually victims get unconscious before dying. When Hulk becomes unconscious (or loses enough conscience level) it's unable to maintain it's rage and so it reverts to be Bruce Banner.
Comment: In the comics, [he does not need an oxygen source](http://scifi.stackexchange.com/q/40059/5184), nor does he need to hold his breath.
Comment: The answer in your comment makes reference to him being able to breathe underwater, not to being able to breathe where there is no oxygen. It states that he can "adapt" to it, but don't link any references.

I recall old comics whith him travelling to space (and different dimensions) and having problems to survive on vacuum. Maybe canon had evolved with time, but old Hulk needed to breathe and it can perfectly explain the question.
Comment: It links to Marvel.com specifically saying he can breathe underwater and links to a scan of a comic saying he can adapt to breathe in space. What more do you want?
Comment: And since the question is about the movie, not the comics, I'm not at all saying your answer is wrong, or incomplete - just noting that the *comics* canon doesn't quite match.
Comment: And Hulk doesn't revert to Banner as he falls in the film, not even a little.
Comment: Downvoted since this relates to the comic and not the film.


Word for a statement that's obvious

Question: I'm trying to remember "the" word which is defined as being a statement said in public which is so obvious that it is embarrassing for everyone to have to listen to. For example: if someone enters a house saying that it's raining outside, which can be clearly seen through a window by everyone inside the house, then this statement is so obvious that it is, let's just say, a statement which is not so intelligent a statement for someone to make - such as the statement I just made. HA
Comment: @deadrat I think it was *The Idiocy*.
Comment: Self-evident might be it.
Comment: I think Homer said it best - [Doh!](https://en.wiktionary.org/wiki/doh)
Comment: @bib Was that from *The Iliad* or *The Odyssey*?
Comment: There should be at least two words.  One to conversation. The comment about the rain is obviously conversational.  A second to describe such a statement that embarrasses.  A layman in a group of professionals might make such a statement.
Answer: When you "state the obvious", it's a truism

From wikipedia: A truism is a claim that is so obvious or self-evident as to be hardly worth mentioning.

In some cases, a "self-evident statement" may be a platitude (or less approriate in the question context, a "cliché").

From wikipedia: A platitude is a trite, meaningless, or prosaic statement, generally directed at quelling social, emotional, or cognitive unease. The word derives from plat, French word for "flat." Platitudes are geared towards presenting a shallow, unifying wisdom over a difficult topic. However, they are too overused and general to be anything more than undirected statements with ultimately little meaningful contribution towards a solution.
Comment: The OED gives platitude as  ' "Commonplaceness"; a commonplace remark, esp one solemnly delivered', eg: 'you can lead a horse to water but you can't make it drink'
Answer: If the statement asserts the same thing in two different ways, such that it cannot possibly be contradicted, then it is a tautology.  Eg, "Either it will rain tomorrow or it won't rain."
Answer: I like glaringly, palpably, conspicuously, unmistakably, and inanely for proceeding the word "obvious" in this case.
A statement of the obvious is also called a truism and/or self-evident.
The speaker or statement can be inane or asinine. They are two of my favorites. (<:
Answer: try 'axiomatic' - although this is not entirely correct.
You enter the house soaking wet and say, ironically "Of course, it is axiomatic that it rains on 1st June".
The most obvious is 'obviously' or you could use 'indisputably':
"You're very wet."
"Obviously, it's pouring with rain."
or "It is indisputably raining cats & dogs."

Word for a statement that's obvious


How and when to use sys_refcursor in oracle

Question: Can some one give me a small explanation about how and when should someone use sys_refcursor ?
Answer: A cursor is a pointer to a result set for a query. By returning a sys_refcursor you allow the client to fetch as many or few of the rows from the query as it requires. In stateful applications this could be used to page through results.
A cursor can allow more flexibility than writing a PL/SQL function that returns an array as it's completely up to the client how many rows to fetch and when to stop. That said, I've not found many cases where this additional flexibility is useful.
It's worth noting that the sys_refcursor is weakly typed, so you can return pointers to queries which not only have different from or where clauses, but different numbers and types of columns as well. Alternatively you can use strongly typed cursor where the columns in the result set are fixed.
This enables you to write functions which return different queries, like so:
create function get_data ( type varchar2 ) return sys_refcursor as
  ret_cur sys_refcursor;
begin

  if type = 'EMP' then
    open ret_cur for select * from emp;
  elsif type = 'DEPT' then
    open ret_cur for select * from dept;
  end if;

  return ret_cur;
end;

However, if you're using sys_refcursor to create a generic "open a query" function like the above you're probably doing something wrong!
Comment: @JohnnyWu a "get me anything" function will be harder to manage. How do you test to ensure you've got the right results in all cases? What about security? This may be necessary if you're building a framework. But for general business logic, it's better to have separate `get_emps` and `get_depts` functions
Comment: @Chris...why is your example function is "wrong?"
Answer: As an example of the possibilities:  because it's pl/sql in back, one can define an object to represent a row, define a pl/sql table of those objects,
create type T_MY_TABLE as table of t_my_object;

and end with
OPEN p_recordset FOR select * from table( v_my_table );

So rather than constructing mongo, often dense and/or cryptic direct queries on a database table, one can create an internal table and have the whole power of pl/sql to populate it.  And the client collecting the result-set is none the wiser.  And changing the definition of the internal table is easier from a management pov than changing a database table.
Also when using report-generators like Jasper, you can push the SQL out of the report and into the database, and just call the procedure to get the recordset, leaving the report-side to focus on the formatting.