Analysing change between two variables measured at 3 points

Question: I have two variables measured concurrently at 3 time points, let's call them wealth (W1, W2, W3) and anxiety (A1, A2, A3). Suppose that wealth and anxiety are uncorrelated. Now, I'm interested whether change in anxiety is related to change in wealth. What would be the recommended way of testing this? Naively I would just create 4 new variables W2-W1, W3-W2, A2-A1 and A3-A2 and look at correlation coefficients between W2-W1 vs. A2-A1 and between W3-W2 vs. A3-A2. Somehow this approach seems silly, since I want a single model that would look at the overall change. Should I be looking at mixed/multilevel models? Specifically which model? Thanks!
Answer: I would look at latent growth curves, or specifically, multivariate latent growth curves. In those models, you have "slope" factors (linear, quadratic, or even "latent basis", where the shape of the change is determine by the data). The correlation between these slope factors can be freely estimated if you decide so.
Software that can run those are virtually any structural equation modeling software, such as Mplus, Amos, the packages lavaan (recommended) or sem in R. I think PROC CALIS in SAS can do it as well, though I'm not certain.
References on latent growth curves:

Kline, R. B. (2010). Principles and practice of structural equation modeling (3rd ed.). New York: Guilford. (see chapter 11) (on Amazon)
Preacher, K. J., Wichman, A. L., MacCallum, R. C., & Briggs, N. E. (2008). Latent growth curve modeling. Thousand Oaks, California: SAGE. (on Amazon)
Answer: One big issue will be level of measurement, since continuous-data (e.g., count-data) require different models than discrete-data (e.g., a single likert scale rating of anxiety, or a choice of a single income bracket where wealth has been polytomized). poisson distributions are often useful for counts, whereas irt models (e.g., graded response, partial credit, rating scale) may better suit polytomous data (see Templin, 2007; Linacre, 2000; Wright, 1998; Ostini & Nering, 2006; Nering & Ostini, 2011).
As for the matter of modeling change, I highly recommend reading McArdle's (2009) great review of latent change models, including those @PatrickCoulombe has wisely suggested. I agree that multivariate latent growth-models seem suitable to modeling overall change, but it's not silly to consider whether changes between consecutive time points are more closely related than overall changes. You can even do both! Take a look at autoregressive latent trajectory (ALT) models (Bollen & Zimmer, 2010), particularly Figure 4 in Bollen and Curran (2004). If you've got plenty of continuous data, or can model continuous latent factors from plenty of discrete data (cf. Regression testing after dimension reduction and Factor analysis of questionnaires composed of Likert items), you might be able to fit some pretty mind-boggling models like these...but that's a big "if"—I've seen rules of thumb for model fitting suggest anywhere from 5 to 20 observations per parameter that needs estimating.
Even without sufficient data tonnage, you might consider a different approach. Comparing nested models with various constraints can produce interesting results for general model comparison hypotheses (e.g., Grant, Langan–Fox, & @JeromyAnglim, 2009). In your case, you might try constraining correlations between first-order latent changes to be equal, i.e. (roughly): $$\text{covariance}(W_2-W_1\ \text{with}\ A_2-A_1)=\text{covariance}(W_3-W_2\  \text{with}\ A_3-A_2)$$
in one model, and then fitting the unconstrained model in which the above is nested. You can compare these nested models with a $\chi^2$ test to see whether the unconstrained model fits significantly better, compare other fit indices to see whether the constrained model might make more efficient (not necessarily in the proper statistical sense of "efficiency", which I honestly don't understand myself) use of parameter estimates. See Wikipedia's section on assessing model fit and Lei and Wu (2007) for some discussion of fit indices (Lei and Wu give a great introduction to sem in general), many of which penalize model fit by the number of parameters estimated. Freely estimating two identical model parameters will thus reduce such fit statistics relative to a model that constrains them to be equal; such a constrained model only freely estimates one parameter for both paths. You might also try looking at modification indices for the constrained model to see whether the constraint is a major source of model misfit to your data's variance-covariance structure.
References
Bollen, K. A., & Zimmer, C. (2010). An overview of the autoregressive latent trajectory (ALT) model. In Longitudinal research with latent variables, pp. 153–176. Springer: Berlin, Heidelberg.
Bollen, K. A., & Curran, P. J. (2004). Autoregressive latent trajectory (ALT) models: A synthesis of two traditions. Sociological Methods & Research, 32(3), 336–383. Retrieved from: http://www.odum.unc.edu/content/pdf/Bollen%20Curran%20%282004%20SMR%29.pdf.
Grant, S., Langan–Fox, J., & Anglim, J. (2009). The Big Five traits as predictors of subjective and psychological well-being. Psychological Reports, 105(1), 205–231.
Lei, P. W., & Wu, Q. (2007). Introduction to structural equation modeling: Issues and practical considerations. Educational Measurement: Issues and Practice, 26(3), 33-43.
Linacre, J. M. (2000). Comparing "partial credit models" (PCM) and "rating scale models" (RSM). Rasch Measurement Transactions, 14(3), 768. Retrieved from: http://www.rasch.org/rmt/rmt143k.htm.
McArdle, J. J. (2009). Latent variable modeling of differences and changes with longitudinal data. Annual Review of Psychology, 60, 577–605.
Nering, M. L., & Ostini, R. (Eds.). (2011). Handbook of polytomous item response theory models. Taylor & Francis.
Ostini, R., & Nering, M. L. (2006). Chapter 3 – Polytomous Rasch models. In R. Ostini & M. L. Nering, Polytomous item response theory models, pp. 26–64. Quantitative Applications in the Social Sciences, 144. Sage. Retrieved from: http://www.sagepub.com/upm-data/5197_Ostini_Chapter_3.pdf.
Templin, J. (2007). IRT models for polytomous response data. Item Response Theory Stats Camp '07, University of Kansas. Retrieved from: http://jonathantemplin.com/files/irt/irt07ku/irt07ku_lecture03.pdf.
Wright, B. D. (1998). Model selection: Rating scale model (RSM) or partial credit model (PCM)? Rasch Measurement Transactions, 12(3), 641–642. Retrieved from: http://www.rasch.org/rmt/rmt1231.htm.


Traces across transmission line

Question: I am designing a PCB which has a chip antenna with a coplanar wave guide.
Having a 4-layer PCB (stackup layer: rf signal, GND, POWER, signal) can I run traces across the antenna transmission line on the farthest bottom layer?
here a picture a CPW just for reference
Comment: What angle are the traces crossing the CPW at?  Also, are the vias full-depth or blinded (stopping at the GND plane)?
Comment: They are crossing it at 90°. Vias are full-depth. Is there any difference in term signal reception if fence vias are full depth or blind?
Comment: Now I have one doubt crossing my mind. It's better to use blind vias for fencing
Comment: ..? If we have full depth fence vias connected from top to ground plane (2nd layer below the top layer) would them act as antennas since they go all the way to bottom layer? The downside of blind vias is the increase of PCB cost.
Comment: ask a new question for that please so it gets the attention it deserves
Answer: Yes, you can run a trace on layer 4 in this scenario. The ground layer on layer 2 means that all field lines from the transmission line are terminated on layer 2, and anything that happens on layer 4 will have practically no effect on the transmission line.
If you are spacing your fencing vias as close as shown in the diagram, you might end up having to skip a via to make room for the layer 4 trace to pass. If you're working below 10 GHz, I don't expect this will create a significant problem. Even at higher frequencies, a single skipped via in the via fence is not likely to cause a noticeable problem (but of course you could do an EM simulation to be sure if your application would be sensitive to a tiny increase in loss or degradation in return loss)
Comment: Many thanks. I am working around 900Mhz. So definitely shouldn't be an issue skipping some vias. I was more concerned the traces running across that could inhibit a proper functioning.

Traces across transmission line


pdf images are RGB, but printer will be printing using CMYK

Question: Most of my images were RAW converted to jpg. I did a book on Costco's website, and the pictures look amazing, but the 60-page landscape-style book (11 x 8-1/2) costs $30 each time it's printed. I couldn't find any partner publishers that do landscape-style books, so I paid someone to do a pdf of the book using AdobeInDesign, so I can give it to Print Ninja (PN) in China, getting the price down to half what Costco charges. Unfortunately I forgot about PN printing the book on an offset printer, and using CMYK, not RGB. I'm concerned that my beautiful nature images will not look the way they do in the Costco book because I've read that CMYK produces a dull image. Without getting too technical, at this stage, is there anything I can do so the PN version of my book will still look good?
Answer: If you were greatly satisfied by the results from Costco, then you will likely be happy with the results from PrintNinja. Both parties have to do color conversions to CMYK and similarly rooted ink systems for images received in RGB (any other color space as well). The difference here is that Costco didn't tell you they were going to do it implicitly.
PrintNinja's website states two options for color conversion from RGB to CMYK, one implicit and one explicit.

Method 1: Let Us Convert Your Colors For You (Less Control)
The simplest method is just to submit your RGB files and let us convert them for you.  We'll show you the CMYK files in your Electronic Proof before going to press, so you'll be able to see exactly how your colors have changed in the conversion process.
However, this method provides the least amount of control for you, since we won't make any changes to your colors beyond the conversion.  If you want to be able to tweak your colors after conversion, you should convert them on your end before uploading your artwork.
Method 2: Convert Colors Yourself (More Control)
If you want the most possible control over your colors, we recommend you convert colors on your end.

If you do nothing further, they will proceed with Method 1, and you can expect the results I've mentioned above.
If it's not too late to resubmit your book, you can do the following to extract the most fidelity from your printing process, and use PrintNinja's second option:

If possible, export your images again from your workflow as 16-bit TIFFs using the "Japan Color 2001 Coated" ICC profile (as mentioned on PrintNinja's page). The ICC profile can be obtained from Adobe here.
Have your designer replace the old images in the InDesign file.
If you have any colored graphics, such as horizontal rules, icons, or vector art in your book, have your designer check for color values that are not specified in CMYK, and select replacement values in CMYK. PrintNinja recommends a number of specific CMYK values for best results.
Also, verify with your designer that the text (presumably in black) in your book is specified using only a K-value (100 or 100% => C=0,M=0,Y=0,K=100), and not the synthetic value (C=100,M=100,Y=100,K=0-100) or any such analogue. Rich Black and similarly constructed color values can cause issues with ink bleed in print.
Last, your designer can export a new pdf file that you can submit to PrintNinja.

One last note, if you wanted to do the same with Costco, they recommend following the preparation guide here for in-store printing; and using profiles from here for send-out printing.
Comment: Darlene, Costco probably uses inkjet or print press, but CMYK and similar derived ink systems are almost universal.
Comment: @DarleneAshley To be even more explicit, pretty much every inkjet printer converts the RGB values sent to it to CMYK since they use cyan, magenta, yellow, and black inks.
Comment: Thank you for your in depth answer. I had no idea that Costco used an offset printer.
Comment: So, are you saying that there wouldn't be much of a difference in how the images look if the printer is using an offset printer versus an inkjet printer?
Comment: They should look similar, as pigments ultimately come from the same manufacturers. Many services in this space try to hide the implementation details of their print processes for fear of overwhelming users with details that they may not understand or even care about. Most professional shops will also do color calibration as part of regular maintenance to ensure color outputs are as consistent as possible.
Answer: RGB is the red, green, and blue pixels as seen on a TV or computer monitor or camera LCD screen. Nothin else works for these devices.
CMYK is cyan (blue-green), magenta (red-blue), yellow and the keying color black. These are the colors of the dyes and pigments that are applied to paper by the printer. If the prints are on conventional photo paper, CMY is used, if the prints are made using ink with dye or pigment, then CMYK. Nothing else works for reflective copy.
Don't worry, all will be OK!


vt100 codes in man-mode

Question: Emacs in this particular installation doesn't parse hyphens in Man-mode. I found the definition and initialization of Man-filter-list, but I don't really know what to do with it, as I cannot really see well the code being displayed incorrectly.
I think, this may also be related to the font not having the hyphen character. So, I'm not sure which direction to take this: try to look for a different font, or try to filter out the hyphens.
Would appreciate a snippet for filtering it out though, just in case.

I just tried changing font, it seems to be unrelated. Also, this appears in ansi-term in Emacs too, i.e. man pages render incorrectly around hyphens (the characters preceding hyphens appear to have a caret on top of them). This doesn't appear in other terminal emulators, like Gnome terminal. However, in XTerm man seems to run in a mode where it doesn't try to hyphenate words (it's slightly uglier, but no botched symbols).

OK, setting Man-switches to "--nh -E ascii" (for no hyphenation and no other weird characters) helps avoiding the botched characters, however, I'd love to know how to have hyphens and have them displayed properly.
Answer: OK, finally, I more or less figured out what the problem was.
Long story short, Emacs was running man with ISO Latin as its encoding system. However, man will still generate a bunch of special characters, hoping that the terminal will somehow interpret that, yet the terminal didn't know how to handle them.
So, one way was to tell man to not to generate strange characters, that is by setting Man-switches to --nh -E ascii.
Or, tell Emacs to deal with Unicode in Man pages by setting Man-coding-system to utf-8.

vt100 codes in man-mode


What benefits does Tau-Chain add over conventional solutions?

Question: I'm currently doing some research on Tau-Chain and its various claims. One of the biggest ways it tries to differentiate itself looks to be the focus on decidable programming languages, instead of turing-completeness. However, I can't seem to find any straightforward example of what practical benefits does that add over the conventional solutions.
Answer: Turing complete languages are undecidable: it can be proved that some algorithm cannot always work as expected for all possible inputs. I believe that most of these problems have to do with deciding if another algorithm can or cannot do something.
An undecidable (programming language) grammar means that you cannot be certain what the meaning of a given program (source code) is just by looking at the code. Look at the answers of this question for examples.
A classic example of undecidability is the halting problem:

In computability theory, the halting problem is the problem of determining, from a description of an arbitrary computer program and an input, whether the program will finish running or continue to run forever.

For completeness also read this, especially the "Mathematical theory" section.
In contrast a decidable programming language can mathematically prove that a program will always have the expected results; e.g. a smart contract written for Tau-chains can be proved that it will not suffer the halting problem before deploying it. It is my understanding that it just helps you reduce possible bugs.
Note, that in Ethereum the halting problem is not a such a big issue since the contract will eventually run out of gas, but it would be good to catch it before deploying it forever in the blockchain!
Having said that, in Tau-Chain they use Ontologies and RDF and in my experience it is much much harder to code anything using RDF and reasoners (although reasoners do allow for smarter programs but I cannot comment more since I do not know the Tau-Chain language's semantics).
Also read this for a comparison between Ethereum and Tau-Chain, from the Tau-Chain guys perspective.


Is it possible to use the 'unity-greeter' for LightDM on Xubuntu 11.10?

Question: I was wondering if there is a way to use the 'unity-greeter' instead of 'lightdm-gtk-greeter' for LightDM on Xubuntu Oneiric. I tried installing the unity-greeter package and changing the greeter-session entry in /etc/lightdm/lightdm.conf, but when I restart the system I get a blinking screen and the boot process get stuck.
Comment: I'm having exactly the same issue.
Answer: Yes, this should work.  Please have a look at /var/log/lightdm/lightdm.log to see why LightDM is failing to start Unity Greeter.
Comment: i have the same issue. and syslog says that : kernel: [   18.799858] unity-greeter[1227]: segfault at 0 ip 00007f3ea4943b70 sp 00007fff665335e8 error 4 in libgio-2.0.so.0.3000.0[7f3ea48aa000+13b000]
Answer: I found a solution for this.. it may work.
In my case, I installed Xubuntu 11.10 - which came with LightDM using the gtk greeter. I edited /etc/lightdm/lightdm.conf to use unity-greeter (after installing it, of course) and had the same issue.
In my case, I fixed it by installing gnome-settings-daemon from Synaptic. Seems it might be required by Unity Greeter, but isn't a dependency.
See: https://bugs.launchpad.net/ubuntu/+source/unity-greeter/+bug/850937
Hope it helps
Comment: That solved the problem almost perfectly. The only issue left is that the unity-greeter seems to be coded to use the Ubuntu indicators in order to display the hour, battery state and the shutdown menu, but I don't want to install them because all the dependencies. By the way, is good to know the bug is reported already.


Mirror telescope: blocked sight

Question: Today I try to watch Venus through a mirror telescope. I am no professional. No matter what lens I take, I see this image: What am I doing wrong?
Edit: What happens when I refocus:Sorry for the bad quality, I didn't manage to make better images. :-(
Comment: That looks like the shadow of the spider for the 2° mirror on an illuminated primary. Your focus would have to be **way** off to see that.
Comment: I second that, this looks like your lens is out of focus. Try to play around with the screws you have on the scope.
Comment: Looks like you're on the right track towards you last image. Can you continue focusing past that point? It might also help to identify what telescope/hardware you're using.
Comment: See the second image in the manual. Both C and D in this image are focusing tools. Unfortunately the manual is not very verbose about what these are and how to use them and I'm not sure anyone here could give more specific information without seeing your telescope in person or being intimately familiar with it. You might get better help by calling the company's help line if you can (or emailing them).
Comment: Try focusing on something on the ground, preferably far away (if you have a view of the horizon that would be ideal).  Venus is a point of light to the naked eye, and it can be difficult to tell when you've focused on it properly. If you're aiming at, say, a distant tree, mountain, or building, it's going to be easier to see a blurry but recognizable image of the target when it's out of focus, and to adjust the focusing knob until it's clear. That will give you at least a rough idea of where you need to be to focus on infinity. *Then* point your telescope at the sky.
Comment: @AtmosphericPrisonEscape I did that, and the results don't quite match what I expect it to be. (edit) Maybe I'm expecting too much? (Changing the lens also doesn't work, I tried all I have.)
Comment: @zephyr When I focus past that point, the image is getting bigger and bigger again, until the first image is reached. Writing on the telescope is "tasco galaxsee".
Comment: The manual for those telescopes indicates there are two ways to focus. A "focus knob" and a "focus tube". Clearly one of these is waaay off as Wayfaring Stranger indicated. Somehow your telescope got really out of whack. You'll need to likely play with both of these two focusing objects.
Comment: @zephyr I can't find anything like that in my manual: http://imgur.com/uxY8KVZ (telescope number is 46-114500)
Comment: Let us [continue this discussion in chat](http://chat.stackexchange.com/rooms/52156/discussion-between-palsch-and-zephyr).
Answer: I think you just need to keep winding the focusser knob, you are way past focus in the first picture but you can see the image get smaller as you approach focus. The last image looks like you may be there or thereabouts, I think the colored diffraction patterns are caused by the camera optics.
Comment: I see the colored diffraction patterns with my eye as well.
Answer: The images in the question show a progression from severely out of focus (large disc with shadow of secondary mirror) to nearly in focus (six-way diffraction pattern). There are a few things you can try:

In daylight, make sure that the the secondary mirror support vanes are parallel to the optical tube axis. This may reduce the diffraction artifacts.
The light from a very bright source will show weaknesses in all but the finest optical systems. Use a neutral-density "moon" filter to reduce the overall brightness.
Point sources make it easier to find the point of best focus. Focus on a nearby star faintly visible to the naked eye, then aim the telescope at the planet and wait for steady air.
Comment: Thanks, I will try that as soon as I will be able to. Currently there are too many clouds in the sky. :-(
Comment: This does not address the obvious massive focus error in the images posted.
Comment: @CarlWitthoft Updated.

Mirror telescope: blocked sight


Why phonemic symbols are different between dictionaries

Question: I find the phonemic symbols are different for the same word between dictionaries. Take the word "tuck" for example. In Oxford Learner's Dictionary, its /tʌk/ for both British English and North American English. However, in Kindle's dictionary which is The New Oxford American Dictionary, it's /tək/.  It doesn't make sense to me that one word pronounces differently.
Comment: You might get /bɪˈfor/ out of somebody as an isolated citation form, but it's certainly going to have to be /bəˈfor/ in any connected speech spoken normally.
Comment: I don't understand your comment, @tchrist.
Comment: Sorry I added wrong phonemic symbols for word "tuck" and have corrected it. @tchrist could you explain it a bit more?
Answer: It doesn't necessarily represent a real difference in pronunciation. The different dictionaries use different conventions.
To understand the reasons for this, you should keep in mind the importance of stress to the pronunciation of vowel sounds in English.
The most standardized use of the symbol "ə" is to represent the "reduced" vowel that is found in unstressed syllables in words like suˈppose or ˈhammock.
For most speakers, this reduced vowel cannot occur in stressed syllables. But the "short u" sound, which can be written "ʌ", does occur in stressed syllables: it is found in words like ˈsupper and ˈmuck.  The "short u" sound that is found in stressed syllables is phonetically similar to the reduced vowel that is found in unstressed syllables. Because of this similarity, and because the stress allows you to predict whether a syllable has the "short u" sound or the reduced vowel sound, it is somewhat common for transcriptions to use the single symbol "ə" to write both the stressed and unstressed vowel sounds. Furthermore, at least some speakers think of these as being the "same" vowel sound in some sense.
In transcription systems that write "tuck" as /tək/, the symbol /ʌ/ is not used at all. This may be considered helpful in that it means that there is one less special symbol for the reader to learn.
Related previous questions:

/ə/ in a stressed syllable?,
Is a schwa ever stressed?,
Difference between /ʌ/ and /ə/ in English IPA
What exactly is the "schwa" sound?
Comment: American Heritage uses *tŭk* and Random House uses *tuhk*, but according to TFD, KEMD uses *tak*. That is neither here nor there, and a [different Kernerman lookup](http://www.lingvozone.com/main.jsp?action=translation&do=dictionary&language_id_from=23&language_id_to=1001&word=tuck&t.x=0&t.y=0) shows *tʌk*, which makes me question TFD's reliability.


Denied permissions for Synchronized Data Extension in Salesforce Marketing Cloud

Question: Can we denied permission for synchronized data extension in Salesforce Marketing Cloud, My requirement is, I don't want to allow users to access synchronized data extension either in contact builder or in Subscribers.
Answer: I don't think you can assign permissions to individual users just for Sync DEs if they have access to the business unit integrated with Salesforce.
You can disable their access to all Data Extensions via Roles but I guess that is not what you really want.
If Salesforce Integration (Marketing Cloud Connector) is configured at a parent Business Unit, Child Business Unit does not have access to Sync DEs in Parent Business Unit, so one option is to only grant Child Business Unit access to some users, so they only have access to Data Extensions in Child Business Units or the Shared Data Extension Folders assigned to that Child Business Units
Comment: Hi Bo Hu,  i enabled Multi-Org connector in my environment and now i hide Sync DE from user because in Sync DE i have universal customers information so now i only have to allow user to see based on that country customer information in business unit but if i will give them sync data extension access then they can see all customer information.


How to use my static IP outside the network?

Question: I want to use my static IP when I'm far away of my network / router. Like to make it portable. I'm not sure how to achieve this. Maybe through a vpn or proxy server? What's the simplest way to achieve this? Thanks.
Comment: So your ISP have given you a static IP? This is what identifies your home (or business) on the Internet... Don't confuse this with a static IP on a LAN... If you have a record of your public IP then you can connect to it from anywhere. Set up port forwarding or a VPN to the IP and whatever you need to connect to will work. A VPN is by far the most secure but you need to configure them and not all "public" access locations (such as cafes, libraries etc.) Allow vpn ports...
Comment: If you have a static IP issued by your ISP, simply buy a domain name and configure it to point to your IP address, or get a free subdomain from [No-IP](http://freedns.no-ip.com/). If your IP is not static (dynamic), then use No-IP or a similar dynamic DNS service all the same.
Answer: In my opinion VPN is best solution.

Make sure if VPN server can work on your internet connection (at home). Some providers may have routers without VPN Passthrough and VPN server cannot work behind that kind of router. It's very rare to see router without it used by internet provider.
Buy VPN router (if you dont have it).
Configure your VPN on router (this may be more or less complicated, some routers have simple creators for VPN configurations)
Configure your VPN on device (laptop?), use static IP inside VPN network or configure router to assign same IP
Configure port redirection on router. You can use only port redirections, you cannot use whole IP because it must handle VPN incoming connections.
Answer: If what you are trying to do is access your PC from a remote location then I suggest TeamViewer http://www.teamviewer.com - works on Windows, OSX, iOS and Android - free for commercial use. I am not affiliated with TeamViewer; I am a satisfied customer.
You do not have any guarantee that your modems IP address will not change unless your ISP provides that guarantee (usually only if you pay more). That said it "tends" to stay the same for long periods of time. You can use port forwarding to a SINGLE machine on your network to do what you asked. It is kind of a pain but not overly complex (Kamil's answer addresses this). Repost if you want to know more about this (it would be helpful to know what kind of router and modem you have as well as your ISP).
Comment: I think he wants more than remote desktop.
Comment: If so then you had a great answer. But if he does just want remote access then TV is much simpler than port forwarding and certainly less expensive than a new router.
Comment: I understand your idea now. However - computer at home must be turned on. We don't know why and how he wants to use home ip remotely, I didn't voted down your question, I just commented.
Comment: TeamViewer is NOT FREE for commercial use.


How long & at what temp do I cook stuffed pork sirloin roast?

Question: I have a supermarket, stuffed pork sirloin roast.  I want to make it today.  It wieghs 2.80#  How long and at what temp do I cook it, and should it be covered or uncovered?  I've never made one of these before, and am unfamiliar with how to prepare roasts, so I have to know every little detail.
Comment: "Every little detail" is very simple - get a meat thermometer. I am sure other people will be able to give you guesses, but depending on the shape of the meat, the type of your oven, and the type of vessel you are cooking it in, they can be very far off.
Comment: Hi Leah, this appears to be more of a recipe request than anything else. I would recommend searching the internet or reading the label of the roast for instructions on how to cook it (most of the prepackaged ones have a label on the side with one). We don't really answer recipe requests since they are not constructive, but if you run into any problems cooking up your roast come back and ask and the community will surely be able to help.
Answer: I have a recipe for stuffed pork loin that I have made using anything from a 3 to 6 pound loin. It's been butterflied, pounded flat, stuffing spread on, then rolled tight & tied with twine.
I bake it for 20 minutes at 475 degrees F, then for an additional 30 to 40 minutes at 325 degrees F, whether the roast is 3 pounds or 6 pounds, and then I just check with a meat thermometer to be sure the internal temp is where I want it.
Answer: Depends on what the stuffing is: if it's minced meat you'll have to cook it through to 70C; unfortunately that's a temperature that will mean the pork is horribly overcooked. Best way would be to pasteurise it at a lower temperature (57-60C) sous vide and then brown afterwards but obviously that's dependant on you having the right equipment.


Is it possible to make homemade crème fraiche using clotted buttermilk?

Question: I started making crème fraiche and when adding the buttermilk, the buttermilk had started to clot.  I didn't know this before adding it to the cream.  Am I still able to make the crème fraiche with this buttermilk?
Answer: Chances are the "clots" are harmless. Give the buttermilk a sniff and a (small) taste. Does it seem OK? If so, the curdling probably just means that the cultures are still healthy and doing their job.
Whisk it in, and stay the course. Your crème fraiche should be fine.
Of course if the buttermilk smells or tastes spoiled, throw it out.
Buttermilk (and to a lesser degree, dairy in general) is kind of unique in the food safety world in that the sniff test is 99.9% accurate. If it smells OK and tastes OK, it almost certainly is OK.
Answer: Buttermilk doesn't necessarily lead to crème fraiche when added to cream, there needs to be an active culture which currently exists in the buttermilk for this to be the case.
If you want to make crème fraiche, one of your best bets is to add a plain yogurt you like to the cream. If you leave the cream out with the yogurt mixed in, it will culture and ferment. After about 4 to 10 hours, it should be ready (depending on starting temperature).
The longer you leave it out, the more sour it will become. You can choose according to your preferences. At room temperature it will still be a bit runny, once it cools it will set more.
Comment: If you add any plain yogurt to the cream, you still won't necessarily get creme fraiche. First, many yogurts don't have a live culture. Second, the ones which have, can have the wrong culture. Creme fraiche is made with mesophilic cultures, if you happen to get a yogurt with a different culture, you will end up with schmand or something else. Basically, by using yogurt instead of buttermilk, you haven't won anything if your goal is to have a higher chance of getting real creme fraiche.
Comment: Most of the time I've noticed people leave the buttermilk outside in order to get a live culture in it, but that would also not necessarily yield the correct culture either. The point of using yogurt is to simply increase the chance that you do get a live culture that isn't harmful. Also, by not heating the mixture, you're sort of making it into a better environment for mesophilic cultures (if they are present), since they'll probably out compete thermophilic cultures. I just suggested yogurt since, short of buying a culture, there is no sure fire way to get such a consistent product.


Ezekiel Temple and Prophecy

Question: The temple detailed in prophecy by Ezekiel chapters 40-48 is very specific in detail. Does anybody have any theological evidence or would like to apply a reasoned assertion that it may ever be fulfilled in the Physical Form detailed?
Comment: Your title asks if it's an unfulfillable prophecy, your question asks if it's an unfulfilled prophecy. These are entirely different. Which do you mean?
Comment: If you asked for an "overview" of the different Christian views on the subject, I think it would be acceptable.
Comment: This question contains too much opinion to be answered well on this site, and it does not fit into one of the [Types of questions that are within community guidelines](http://meta.christianity.stackexchange.com/q/3409) If possible, [edit] this question so that it better fits into one of those question types.
Comment: Perhaps I should have suggested it be moved to the BH site. NicPhillips seems to be looking for a hermeneutical approach.
Answer: Throughout the Book of Ezekiel, the theme often changes dramatically from chapter to chapter, returning in a later chapter to a previous theme, with some of the symbolism being obscure and some of it extremely offensive to modern readers. However, the earlier chapters are essentially a condemnation of Israel and Judah for worshipping other gods. Then, Ezekiel gradually changes to themes of hope and comfort. The Book of Ezekiel is notable for the careful way in which the author regularly tells us the exact date on which he receives his visions. Thus we know that Ezekiel is prophesying after the destruction of Jerusalem and the first temple.
Chapter 37 is notable for the promise that Israel (Ephraim) and Judah will soon be reunited as one nation upon the land, and never again divided into two kingdoms. David (his descendants) shall be their king (37:24-25). The Jews could hold onto these prophecies in their long period of exile, even if they never came true after the Return from the Exile.
Chapter 38 tells of an apocalyptic invasion of the now united and prosperous land of Israel by the legendary Gog of Magog. When Gog invades Israel, the fury of God shall be aroused against him (38:18). Yet this invasion from the north will be instigated by God himself, so that all the nations will know him (38:14-16). Having led the armies of Gog against Israel, God will then ensure their total defeat, such that it will take all the people of the land seven months to bury their carcasses (39:11-12). This is another prophecy that never came true, but it was probably the kind of heroic epic the Jewish exiles wanted to hear.
The book ends, in chapters 40-48 with the promise of a new Israel, a new Jerusalem and a new temple.  Measurements are carefully taken so that the new temple will be on the same grand scale as the old one. Chapter 43:7:

"The voice said to me: Son of man, this is where my throne shall be,
  this is where I will set the soles of my feet; here I will dwell among
  the Israelites forever. Never again shall they and their kings profane
  my holy name with their harlotries and with their high places."

Ezekiel's temple was built, just as he prophesied, although perhaps not to his exact plan.
Comment: What do you mean it was "rebuilt"? There was never a physical structure that matched the floorplan of Ezekiel's temple... ever. If you mean it's allegorical, that could be a *lot* clearer. If you mean the Second Temple matched Ezekiel's description, then it's not correct.
Comment: @Mr.Bultitude Thank you. I concede your expertise on this and have adjusted accordingly.  Of course, Ezekiel was not prophesying in the sense we use today, just giving his people hope.
Comment: `This is another prophecy that never came true, but it was probably the kind of heroic epic the Jewish exiles wanted to hear.` It hasn't happened yet, the way you word it makes it sounds like it never will. It will, same battle described in Joel Chapter 2 and Revelation.
Comment: @DickHarfield "Ezekiel was not prophesying in the sense we use today, just giving his people hope." Can you find a reference to support this? I'm aware of three main views on the prophecy within Christendom: 1) it will be fulfilled symbolically; 2) it has been/is being fulfilled symbolically; 3) it will be fulfilled literally. I've never heard the view you're referring to.

Ezekiel Temple and Prophecy


How much load for a given source?

Question: Given a micro controller with X Volt DC power supply, what is an easy way/rule of thumb to determine how much devices I can connect to the controller (assuming each device requires Y Volt DC)?
Comment: If X != Y, then the answer is 0. If X == Y, then you don't have enough info because you need to know the current required by each device and how much current your PSU can supply.
Comment: there is no rule of thumb ..... you have to refer to the controller datasheet to determine how much current each pin can source or sink
Answer: Assuming you mean a microcontroller module, the key circuit is the power supply circuit of the module, not the microcontroller itself.
To be powered directly from the same power supply, the peripherals must all use the same voltage as the supply provides. If it's a 3.3 V supply, the peripherals must all run from 3.3 V.
The number of peripherals that can be powered doesn't depend on the voltage, but on the current drawn by the peripherals. The total of the currents drawn by all the peripherals (in every operating mode or operating condition) must be less than what the power supply is designed to provide.

How much load for a given source?


Problem with UItableview reload data using alert view with prompt on a custom cell

Question: I have a UItableViewController with a custom cell designed using interface builder. The custom cell has a button and a label on it. The button when click will trigger an alert view with prompt. Once the text is entered and press OK the label on the cell will display the updated info on the table. The problem is the label will not get updated until I click on one of the cells. I cannot use [tableview reloaddata] because I am using IB and it creates a separate .h and .m UItableViewCell files and this is where I put the alert view with prompt code in it. How can I call reload data to update the table when the alert view is dismissed. I have put [tableview reloaddata] in the UItableViewController under viewWillAppear, but it does not work.
Answer: You could keep reference to UITableViewController and call reloaddata on it from cell.
Answer: I have figured it out. See code below:
UItableView *tableView = (UItableView *)self.superview;
[tableView reloadData];

The self.superview is the trick!
Answer: I am fairly new to iPhone development, however, one of the design patterns I have seen again and again is delegation. This allows you to extend functionality while maintaining reusability of your components.
I believe you can set a delegate for a UIAlertView and then implement the protocol on your main UITableViewController via  in the @interface definition. This means that your controller will be notified of events as they pertain to that particular alert as long as you set the delegate property in your AlertView object after instantiation.
Take a look at the function...
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex

If you set up the above delegation, then overload this function, you should be able to call [tableview reloadData] when the alert view is specifically pressed.
Also -- is there a reason you can't define the IBAction method that the button calls in the UITableViewController? This would allow you to avoid passing around the parent of the cell, seems like a better adherence to MVC.


Reverse Sony Vaio language choice

Question: When first booting a new Sony Vaio laptop (VPCEB2E1E/WI), I had to make a language choice (it warned me that this choice would be irreversible). Since this seems to be just software, I wonder how that's irreversible... and I'd really like to undo my choice. Any hints?
Answer: From the wording of the question I'd say that Windows is pre-installed with multiple language options. When you select a language it does "some magic" under the hood finalizing the installation, probably at least deleting the extra language files, etc.
Some sources say that it's possible to change the initial langage selection but it takes quite a bit manual work. The easiest way is to re-install Windows completely, but I'm not sure if the restoration copy that can be burned to DVD after installation is enough, or would one need a fresh (full) copy of Windows.

Reverse Sony Vaio language choice


Only showing unanswered questions!

Question: A day ago I went (for the first time) to the task "UNANSWERED". After that, whenever I go to the "ALL QUESTIONS", when I go to the second page (and more), is ONLY shown unanswered questions! That is very strange! ¿Why?
Comment: I'm not exactly certain where you are in math.SE's tabs. My almost think that your "QUESTIONS" tab is set to the "unanswered" subtab. In this case, just switch over to a different subtab (like "newest").  If this is not the case, could you post a screenshot (or somehow indicate exactly where you are in the tabs)?
Answer: Via cookies, the site tries to remember your preferences.
If you visited the "unanswered" tab, the "unanswered" tab will become your default preferred tab. To switch to a different tab (for example "active"), click on the preferred tab and it should be remembered from now on.
The same is true for the sorting of answers. You have three choices, "active", "oldest", and "votes". Selecting one out of the three will mark that as your preferred viewing method, until the next time you make a selection and chooses a different sorting method.

Only showing unanswered questions!


Controller tests for RESTful actions

Question: Although I generally use the Fat Model, Skinny Controller approach I can see the point of testing complicated controller actions, but I'm wondering: Is there any reason to write controller tests for the RESTful actions generated by rails scaffolding?
Answer: From my experience, your controller specs or tests help to debug paths or values in an action. Often, you'll see:
<code>@post = some_logic_gets_a_post
if @post.present?
   # happy path
else
   # failure path
end
</code>
With the controller tests you can make sure, you'll enter the right state under your assumptions, or that you hit the correct exceptions.
Answer: In general I find it useful when testing authentication and authorization, at this point I don't really care what the content returns but more if I get the right redirects, status codes etc.
A second case where I value controller tests is when the controller can answer in more than one dialect. e.g. JSON, XML and/or HTML. However when the formats get complex it's better to do this with a builder and not hide this complexity in controllers.
Answer: Simply Put: If you have code in your application, maintained by you, test that code.
I avoid writing tests for actions or behavior provided by InheritedResources or other REST gems, but once there is logic, especially redirect and authentication/resource ownership logic, it should be tested. Notably, the last time I used scaffold and rspec it generated all those tests for me as well.

Controller tests for RESTful actions


What is the difference between linux and windows from web application testing point of view

Question: What is the difference between Linux and Windows from a web application testing point of view?
Comment: It might be very different, or same, depending on what you are testing.
Comment: Hi Iqra, your question is quite broad in a way that we can't give you a definitive answer. This means your question risks being closed, unless you're able to expand on the issue and ask for something more specific?
Comment: Hi, I want to ask testing perspective to test an application on Linux and how it is different from Windows. Thanks
Answer: From the testing point of view tester's needs to consider the following:

Make sure Javascript gets loads properly in both OS versions
Design issues will occur make sure the CSS gets loaded properly when testing in a application in Windows and linux
Some of the Ajax calls may not work in linux but will work on windows or viceversa.
Answer: Everything is different.
You're trying to test the same web app on two different systems and that'll affect everything - functional, non-functional, performance, penetration tests, etc.
Even the browser you're using will be different between the two operating systems, so you're effectively testing two different web apps.
In my experience, a large portion of your test cases will remain the same between the two systems (because the functionality will be very similar) but you'll have have to run them twice. Once on Linux, and again one Windows.
Comment: can you elaborate more about functional, non-functional, performance, and penetration tests ?


Visibility of template specialization of C++ function

Question: Suppose I have fileA.h which declares a class classA with template function SomeFunc<T>(). This function is implemented directly in the header file (as is usual for template functions). Now I add a specialized implementation of SomeFunc() (like for SomeFunc<int>()) in fileA.C (ie. not in the header file).
If I now call SomeFunc<int>() from some other code (maybe also from another library), would it call the generic version, or the specialization?
I have this problem right now, where the class and function live in a library which is used by two applications. And one application correctly uses the specialization, while another app uses the generic form (which causes runtime problems later on). Why the difference? Could this be related to linker options etc? This is on Linux, with g++ 4.1.2.
Answer: It is an error to have a specialization for a template which is not visible at the point of call. Unfortunately, compilers are not required to diagnose this error, and can then do what they like with your code (in standardese it is "ill formed, no diagnostic required").
Technically, you need to define the specialization in the header file, but just about every compiler will handle this as you might expect: this is fixed in C++11 with the new "extern template" facility:
extern template<> SomeFunc<int>();

This explicitly declares that the particular specialization is defined elsewhere. Many compilers support this already, some with and some without the extern.
Answer: Have you added a prototype with parameters to your header file?
I mean is there somewhere in fileA.h
template<> SomeFunc<int>();

If not that's probably the reason.
Answer: I had the same problem with gcc4, here is how i solved it.  It was more simple a solution than what i was lead to believe by previous comments.  The previous posts ideas were correct but their syntax didn't work for me.

    ----------header-----------------
    template < class A >
    void foobar(A& object)
    {
      std::cout << object;
    }

    template <>
    void foobar(int);

    ---------source------------------
    #include "header.hpp"

    template <>
    void foobar(int x)
    {
      std::cout << "an int";
    }

Answer: Per the specs, your specialized function template should never be called outside fileA.C, unless you export the template definition, which no compiler (except Comeau) currently supports (or has it planned for the forseeable future).
On the other hand, once the function template is instantiated, there is a function visible to the compiler that is no longer a template. GCC may re-use this definition across different compiler units because the standard states that each template shall only be instantiated once for a given set of type arguments [temp.spec]. Still, since the template is not exported, this should be limited to the compilation unit.
I believe that GCC may expose a bug here in sharing its list of instantiated templates across compilation units. Normally, this is a reasonable optimization but it should take function specializations into account which it doesn't seem to do correctly.
Answer: In Microsoft C++, I did an experiment with inline functions.  I wanted to know what would happen if I defined incompatible versions of a function in different sources.  I got different results depending on whether I was using a Debug build or a Release build.  In Debug, the compiler refuses to inline anything, and the linker was linking the same version of the function no matter what was in scope in the source.  In Release, the compiler inlined whichever version had been defined at the time, and you got differing versions of the function.
In neither case were there any warnings.  I kind of suspected this, which is why I did the experiment.
I assume that template functions would behave the same, as would other compilers.
Answer: As Anthony Williams says, the extern template construct is the correct way to do this, but since his sample code is incomplete and has multiple syntax errors, here's a complete solution.
fileA.h:
namespace myNamespace {
  class classA {
    public:
      template <class T> void SomeFunc() { ... }
  };

  // The following line declares the specialization SomeFunc<int>().
  template <> void classA::SomeFunc<int>();

  // The following line externalizes the instantiation of the previously
  // declared specialization SomeFunc<int>(). If the preceding line is omitted,
  // the following line PREVENTS the specialization of SomeFunc<int>();
  // SomeFunc<int>() will not be usable unless it is manually instantiated
  // separately). When the preceding line is included, all the compilers I
  // tested this on, including gcc, behave exactly the same (throwing a link
  // error if the specialization of SomeFunc<int>() is not instantiated
  // separately), regardless of whether or not the following line is included;
  // however, my understanding is that nothing in the standard requires that
  // behavior if the following line is NOT included.
  extern template void classA::SomeFunc<int>();
}

fileA.C:
#include "fileA.h"

template <> void myNamespace::classA::SomeFunc<int>() { ... }

Answer: Unless the specialized template function is also listed in the header file, the other application will have no knowledge of the specialized version.  The solution is the add SomeFunc<int>() to the header as well.
Answer: Brandon: that's what I thought - the specialized function should never be called. Which is true for the second application I mentioned. The first app, however, clearly calls the specialized form even though the specialization is not declared in the header file!
I mainly seek enlightenment here :-) because the first app is a unit test, and it's unfortunate to have a bug that doesn't appear in the test but in the real app...
(PS: I have fixed this specific bug, indeed by declaring the specialization in the header; but what other similar bugs might still be hidden?)
Answer: @[anthony-williams],
are you sure you're not confusing extern template declarations with extern template instantiations? From what I see, extern template may only be used for explicit instantiation, not for specialization (which implies implicit instantiation). [temp.expl.spec] doesn't mention the extern keyword:

explicit-specialization:
      template < > declaration


Why do AC-to-DC adapters have long cables on both ends?

Question:
Why do AC adapters have long cable on both ends? I believe that almost everyone using one would want it either directly next to the gadget it is powering (even possibly joined together with it if possible) or next to the power plug (possible made into a single unit with the power plug). It is inconvenient to have it hanging in the middle of a power line. Is this simply a design flaw, or does it have particular reason?
If I were to replace either the AC side or the DC side cable with a very short one, does it have any difference between the two options electronically?
Comment: AC-to-DC wall-warts don't have long cables on the AC (mains) side...
Answer:
Usually for thermal management or mechanical compliance.

thermal -- placing the power supply away from the potentially hot device and away from the wall (better airflow) results in the most efficient operation.
mechanical -- large power supplies would block adjacent outlets if connected directly. They can also be heavier than can be safely suspended (hung) from wall outlets.

Basically no... except for the above mentioned reasons.
Comment: @JoeBaker and that voltage drop would be factored in by the manufacturer either way.
Comment: Theoretically you could have a voltage drop on the DC side from wire resistance, but that would only be significant for a much longer cable than you will likely ever see in this configuration.
Answer: Two main reasons. Ease of use, and appearances. Ease of use because sometimes the power supplies are too bulky or heavy to plug right onto a outlet or power strip. You can even buy mini extensions just so that you can plug a wall wart into a power strip without taking 4 spots.
On the other side, it can be extended for the same reason. A power adaptor might be a pound or three, and you wouldn't want that extra weight on a laptop or monitor. And then there is aesthetics and appearances. The cable length allows the bulky, ugly power adaptor to be hidden. Again, with like a monitor or printer or anything really, you don't want to have to put the power adaptor right next to the device, on a desk, or hanging half way off the device. You get a generous length so it can go flat on the ground where it can't be seen, where it will get proper air flow as well.
Answer: When doing EMC testing in order to meet legislation a long cable on the AC end can reduce the conducted emissions back to the AC because of the filtering the longer cable provides. This assumes the adapter is a switch-mode type. The longer cable can reduce the adapters susceptibility during EMC testing too.
Answer: I think there is one more reason, outside of what has been mentioned already. Laptop power supplies can be changed to be used in multiple countries just by replacing the cable that connects the power supply to the outlet. Specifically, what I have in mind is the C13/C14 connector:

(image credit: Museo8bits via wikimedia commons)
If there were no cable to replace, similar flexibility w.r.t to outlet types would require replacing just the prongs, which could be more mechanically difficult. Also given that large (computer) power supplies can use the same cable, and such power supplies require a cable (you cannot locate a desktop power supply immediately adjacent to the wall), the same cable can be used both for desktop power supplies and laptop power supplies, increasing their utility and ubiquity.
Comment: Not just C13/C14, but C1-C8 are also common. The Figure 8 and Mickey Mouse connectors used on Playstation 2, Dreamcast, Power/MacBooks etc.
Answer: The AC cord has to be long enough that the user can put the box on the floor, even if the outlet is fairly high on a wall somewhere, or otherwise in some inconvenient place. With cables, it's better to err on the side of too long. A few inches of excess length is a minor inconvenience compared to a few inches of insufficient length.


How to combine categorical features to predict continuous output

Question: I have many categorical features that are non-nominal and also continuous features with continuous output. Some of the categorical features are binary and others have 10+ classes. How would you go about building a model to make continuous predications? I was thinking of using some sort of decision tree to learn on the both types of data or maybe have two separate classifiers for each data type and combine the predictions. Should a neural net be used for this?
Comment: What do you mean that your categorical variables are non-nominal? Do you mean there is an order to them like good/medium/short or tall/grande/venti? (That second one is a Starbucks joke.)
Answer: Consider effects coding your categorical variable. You will estimate how much of an effect each category has on the outcome and use that in the model instead of the category itself. There is an R package called vtreat that will do this for you. For more details look at this blog post.


File format or method of exporting per-vertex roughness values

Question: I am working on a project that necessitates an automated export of blender objects with materials to basically any file format that supports diffuse and roughness maps. However, some objects have topology too complex to be smart-UV unwrapped and thus cannot be texture baked on. To remedy this, I was able to use .fbx to export vertex colors. Is there a method of annotating vertices with roughness and a file format that supports it? In essence, I need to avoid the use of UV unwraps but still export roughness and diffuse data.
Answer: Once your roughness is tuned to your liking, (depending on what facilities you have to further adjust it in your destination application,) you can plug it straight into the material output, and bake its resulting Emission into a Color Attribute you've set up for the purpose:

On the left, the original texture. On the right, picked up from the baked Attribute:

If you needed to, with a Combine RGB you could arrange your shader-tree to feed 3 float/monochromatic parameters into the R,G,and B of a single  Color Attribute.
The attribute's resolution will obviously depend on the density of your mesh.
Comment: Fbx was just an example - quite literally any file format or application that might support this pipeline would be fine. Basically I just need to get roughness and diffuse/color data into any file format out there without utilizing UV unwraps. one hacky solution maybe would be to write my own uv unwrapper that maps all the points into a completely disjoint texture map and then generate a roughness maps from there, but I wanted to see if there were any other options
Comment: This is great, but do you (or anyone else reading) know if its possible to export color attribute data out of Blender? As far as I know, shader node IO only supports image textures during export (and remember that I am unable to uv-unwrap/texture bake). I could export vertex colors/color attributes via .fbx, but the question remains of how I could link the per-vertex roughness data in my roughness color attribute layer to whatever fbx uses internally to represent roughness.
Comment: @user167693  Ahh, I see, I've slightly misunderstood you, haven't I? This is more like a .fbx question..
Comment: @user167693  What application are you aiming at?
Comment: @user167693 a quick search suggests most renderers in most applications can pick up vertex color layers from .fbx , and use them for whatever you like? .. but that would mean checking with them, not Blender. (Needless to say.. the .fbx can be exported from Blender and re-imported, 'Roughness' survives as a named layer.)


How to code mp3 file on webp page for Android Froyo 2.2?

Question: I have tried HTML 5 tag and that does not work. I have also tried jPlayer and that does not work as well. I need a mp3 player that will play on Froyo 2.2. Any suggestions or direction would be very appreciated.
Answer: jPlayer just makes the <audio> tag for you, so both of those are attempting to do audio through HTML5, which the FroYo browser does not support (Gingerbread does, though). The easiest way to play the audio would be to make the audio into a Flash video and insert it that way.
Answer: jPlayer's default Solution parameter (html5, flash) does not reliably fallback to use its Flash player in Android 2.2 and higher. At least in those versions of Android the device gives jPlayer a false positive indicator that it supports html5 and, so, the Flash fallback is never called. To make jPlayer work for the Android just revers the default order in the Solution parameter to flash, html5. jPlayer then just grabs the Flash player and runs the media.
The iPhone, given that it doesn't support Flash, will simply fail on the Flash parameter and fallback to HTML5 as it should.


How to find out if the if a site user is unique or a returning user in ASP.NET?

Question: A single user can show up as multiple unique users over a period of time when he vists a site. Internally, the user's IP address is static, but on the net the user is represented by the ISP router's IP address, isn't it?
Answer: You can't be guaranteed that a user is unique by IP Address.
Companies might be operating behind a firewall/proxy so all requests will come from that single IP.
Probably your best bet would be to drop a cookie on to the users browser when they browse to the site, and then check for the existence of that cookie on subsequent visits.
But even this doesn't guarantee you as there is nothing to stop the user from clearing their cookies in the browser, or visiting once from IE, and the next time from firefox.
In a nutshell, there's no guaranteed way... but there are ways to make a pretty good guess
Answer: For every client that comes to your site, assign him a unique ID and store it in a cookie. Then check for that cookie every time your site is hit, and set it if it is missing. Then you can log client usage by unique ID.
Usually the IP address you see from the client is the IP address the client's ISP has provided for him. These are often dynamic. Clients behind proxies and routers will share IP addresses. Either way, assigning a unique cookie to each client circumvents these problems.
It won't work for clients with cookies disabled. You'll have to default to the IP address for those, and risk the data being incorrect. Or you could just not log this kind of user, in which care your data will be incomplete. There's no reliable way to uniquely distinguish between every user, so you just have to pick which method makes the most sense for your site.


Does "shortened" have a negative connotation in "shortened time to load"?

Question: I am not a native speaker of English, and I'm having a problem at work regarding the word "shortened". I used this word to express that our new product can now load XXX much faster than the previous model:

Shortened time to load XXX

I received feedback from other people (also non-native speakers of English), who say that this expression contains a "negative meaning". Is that true?
Answer: Your colleagues are wrong.  People do not like waiting for programs to load and start.  Progress bars are much hated, partly because of their unreliability but also because waiting while a file downloads or a program starts or a video finishes buffering is often a tiresome and depressing experience.
The verb shorten is semantically neutral and has no negative connotations by default.  Shorten a pleasurable experience and people will regret it.  Shorten a painful one and they will thank you.  On your presentation, the use of this phrase is a win.
Perhaps your colleagues are confused because the adjective short can be seen as an insult, or at least a way of diminishing a person´s importance, when applied to their stature.
Use the phrase.  It is well chosen.
Comment: More idiomatic would be 'faster time', or, if true, 'greatly reduced time'.
Comment: The first one *might* be more positive - I don´t personally see it as better, just an alternative. As you say, the second requires justification.  I don´t have that data so I am just answering the question.
Comment: I'm saying it's more idiomatic (ie used more often). This is my perception; these [Google Ngrams](https://books.google.com/ngrams/graph?content=a+shortened+time%2C+a+faster+time&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Ca%20shortened%20time%3B%2Cc0%3B.t1%3B%2Ca%20faster%20time%3B%2Cc0) support this belief.
Comment: So it doesn't have any negative image! I'm very happy to know your detailed comment about my question. So, I will not change this word in the Power Point. Thank you very much, indeed.
Comment: Do spell it *¨shortened¨* ;)
Answer: Actually, you've provided your own answer.
People have been conditioned to consider the relationship between time and computer software in terms of speed ("fast") versus duration ("short").
So when you "express that [your] new product can now load XXX much faster," then that's exactly how software users expect to have an upgrade presented to them. For example, you could say something like "Our new product loads 30% faster!"
Although a "shortened" load time is technically correct and expressing it in terms of duration is accurate, that's not the point. The point is employing verbiage that resonates with your software user base. Use the words they expect you to use; the words that mean the most to them.
Answer: Shortened brings into play a negative, making one immediately picture your product as perhaps being too slow in the first place. A forward looking expression might be "With exceptionally fast load times".


Can a company reverse hiring decisions?

Question: I heard a  story about someone who got a health care job but lost the job before she started it because she shared about getting the job on social media. Do companies usually tell applicants not to share on social media before they enforce such a policy or do they enforce that policy without warning?
Answer: There is neither a common policy nor any reason or "cause" to fire someone over a "I got a new job with ACME corp, that's so great!"-facebook post.
You should read the story and the details behind it very carefully.
What is cause for termination in most countries is actually publicly talking bad about your company. So if someone posted "I have to work at ACME corp, they suck so bad and I'm sure my new boss is personally clubbing baby seals and eating kittens" then yes... that would probably lead to a termination of the contract. But then, maybe it's better for both of them to not work together.
Comment: Another reason for termination is for revealing details about the job. The guy in [this article](http://www.dailydot.com/news/google-employee-fired-reddit-post/) was fired for talking about an unreleased product, and the article notes that the NDA he signed was for talking about any part of the training or job.
Answer:
Do company's usually tell applicants not to share on social media
  before they enforce such a policy or do they enforce that policy
  without warning?

Most companies don't want to fire people. They want employees to succeed and be around for the long term. Hiring and training new employees is typically far more expensive than retaining them.
If something is important enough to be a fireable offense, most companies either make it explicitly known, or consider it common knowledge.
For example, if a company would fire you for using social media, they would likely make it clear what you can and cannot do regarding social media.
On the other hand, most companies assume you know that stealing company property or publicly trashing your employer is grounds for immediate dismissal.
Answer:
Do companies usually tell applicants not to share on social media before they enforce such a policy or do they enforce that policy without warning?

Yes, termination for failure to comply with some policy can only be done if the policy has been effectively communicated. You can't fire someone for a policy they cannot reasonably be known to exist.
On the other hand, the person is not hired until they actually start, so, in this case, they probably were not so much 'fired', as 'not hired', or, put another way, their job offer was 'withdrawn before the hiring happened'.
Still, even then, it is common practice for companies to hire on 'probation' for a limited length of time (a month or three), wherein the employment can be terminated with no reason given at all.
There's so much that could have happened here, that it's not worth speculating on. The fact that she posted to facebook may have led someone to see she was 'liked' by someone else, and that someone else was the problem. You cannot assume that the facebook post itself was the cause.

Can a company reverse hiring decisions?


Witness data storage localisation in the blockchain

Question: Since segregated witness is in place inside Bitcoin blockchain, my understanding is that witness data are no longer stored inside the blocks, so if blocks are linked to each other where theirs corresponding witness data are stored ? There is a parallel block chain ?
Answer: If the client is SegWit enabled, the full transaction including witness data can be stored in the same format as the transaction is received over the wire. There is no need for separate storage - it can all be included in the block.
If the client is not SegWit enabled, SegWit transactions are stripped of their witness and the witness marker/flag before sending/receiving, so these clients will not receive witness data, and therefore will not store it at all and will only use the legacy format.
This means the block storage between the two clients is different, but they are still sharing the same blockchain and transaction history.
Compatibility is made possible because even when SegWit is used and the witness is present, the SegWit client will calculate a txid by stripping the transaction back to its legacy format (removing the witness parts) before hashing. The txid is common between the SegWit and non-SegWit clients as a means to identify which transaction is being referred to. SegWit clients can identify data by a wtxid too, which is the hash of the serialized transaction with witness format - but this wtxid is not used as part of a txOutPoint to refer to a previous transaction - the txid is always used.
SegWit transactions are forward compatible with non-supporting software clients because the transaction with its witness data stripped from it appears as though it is an ANYONECANSPEND transaction - the stack is left with a non-zero value on top after evaluating the scriptPubKey, which is indicates successful evaluation.
Comment: I read @Guillaume07 question as more related to the [block serialization structure](https://en.bitcoin.it/wiki/Block) rather than the TXN serialization structure.  Obviously the witness data is thunked into the TXN after the fact and must exist outside of the normal block serialization to exist at all.

To Guillaume07 question, I think it is just concatenated on to the end of the block.  Non-segwit clients will just stop parsing after the last TXN, and segwit clients would keep scanning.

The witness merkel tree is stored in the coinbase TXN as an OP_RETURN UTXO.


The default value of timeouts on selenium webdriver

Question: I am interested in the default value of timeouts on selenium webdriver.
ImplicitlyWait, SetPageLoadTimeout and SetScriptTimeout.
Because I want to know, Do I need to set a values for those timeouts? or the default value is good for selenium webdriver working.
But I cannot find a correct answer, someone say the default value is 0, and other one say it is 30 sec.
Answer: These three timeouts are managed by the server-side of the Selenium equation. Your script, be it in Java, Python, Ruby, C#, or whatever, is a client that sends commands to a server that lives in the browser. (There may be an intermediary that relays commands to the browser, like Selenium grid. Unfortunately, it is also sometimes called a "server".)
The WebDriver specification, which was derived from Selenium has settled on the following values:

For implicit waits: 0 seconds. This means that if a selenium command does not find an element immediately, it reports immediately, rather than wait until an element is found.
For page loads: 300 seconds.
For script timeouts: 30 seconds.

(The specification gives the values in milliseconds. I've converted them to seconds for ease of reading.)
Selenium now follows the WebDriver specification.

In the past Selenium has used other values for these, however. For instance, the Firefox driver used to define its timeouts like this:

The implicit wait timeout is set to 0 by default. This means that if a command that finds elements does not find anything, it won't wait.
The page load timeout is set to -1 by default. This means that Selenium will wait indefinitely for the page to load.
What Saifur found is not the same as the page load timeout. That's a timeout between the Selenium client and the Selenium server, which is not particularly well explained on the page Saifur found.
The script timeout is set to 0 by default. A comment in the source code explains:

The amount of time, in milliseconds, this session should wait for asynchronous scripts to finish executing. If set to 0, then the timeout will not fire until the next event loop after the script is executed. This will give scripts that employ a 0-based setTimeout to finish.

So even if it set to zero, an asynchronous script can still execute but it has to complete before Selenium's timeout gets a chance to run again.

This is from the code that Selenium uses for Firefox. The other browsers use different code bases but they are supposed to behave consistently, at least with regards to things that are proper to Selenium itself, like these timeouts. So the values and their interpretations should be the same for other browsers too.
Answer: For implicit wait always default wait it ZERO. , you can check it here :
Selenium Webdriver diff. waits
And if you set custom time then web driver will wait to get element till that time and if element does not found till that time then only web driver will throw exception.
Answer: The Selenium documentation is very much unclear on these timeouts.

According to
this
the default timeout of the implicit-wait is 0
According to
this
any page that does not load in 60s will return http communication
timeout unless you explicitly overwrite the timeout.
Unfortunately, I did not find any reference to provide on
ScriptTimeout. But, it's defaults to 0 according to my knowledge
and experience. Will update you with any reference later
Comment: What about that script timeout? What is the value? I am facing this problem right now. My script fails on page load and I dont know why. If it is script timeout or pageload timeout or what... Hope somebody knows.
Comment: @Čamo as I mentioned the scriptTimeout is also 0. You can definitely set it for async script execution. Without knowing much about the implementation cannot really help. Are you executing any javascript that fails?
Comment: I mean page is blank on screenshot. No content at all. I looks like slow connection sometimes cause the test sometimes pass and sometimes not. Still the same test with the same code.


How do I view a song's composer on my iPod touch?

Question: Is there any way of viewing the composer of a particular song in the Ipod Touch? I know you can sort songs by composer, but what I want to do is while listening to a particular album (classical music), view the composers of the different songs.
Answer: There's a small app you can find here
Don't worry, it's all Japanese. But the app works really fine and reads all (!) ID3 tags of the current song playing.
Since I am listening preferably to classical music, too, I hate iTunes non-existent ability to show all relevant tag information.
Comment: Me too. I want to display all the text from any tag without truncation. This is my number one gripe about the iPod touch and the iPhone.
Comment: I tried this and it is working great. I am using it on an iPhone using the new "Music" App. If I am looking at "New" Albums, the app leaves the composer field blank. However, if I add the album to "My Music" I can then see who the composer is. I guess if I am curious about who wrote the music I can always add the album to "My Music" and then take it right off. Thanks!
Answer: I don't think this is possible in the default 'Music' app which is quite simple and straightforward. The only solution would be to add the composer to the track's title but I suppose you already thought about this one...
Finding another app for paying music but with more options would be another solution. Are you open to having another application for playing music?
Comment: Any example of an app that actually allows this would make this an excellent answer. Any thoughts?
Comment: Browsed for more than one hour on the AppStore. Tried several free apps without any success at the moment. Didn't try to paid one obviously. It doesn't seem to be a feature requested by a lot of people whereas I understand the need in case of classical music. Strange no application is providing it.


YA book about paper mâché dragons coming to life

Question: i remember reading a young adult book about a teen in modern times (1980-1990) who makes a bunch of paper mâché dragons as a hobby and they end up coming to life and attacking him in his home.   I have no idea the title or author  but I recollect the cover drawn as the main protagonist in a chair as the dragons come find the stairs behind him.  Any help!?   I have scoured the Internet for l the last 5 years on and off with no luck.
Comment: Are you certain it's dragons? I remember something very similar involving them being gargoyles. They had an electronic chip in them to give them limited speech, he'd added some fur to them, and their eyes could glow. He wanted to sell them as toys, but hadn't found a buyer due to their grotesqueness. The cover did show all three of them moving down the stairs as he sat there. Unfortunately, the name escapes me if it is that one.
Comment: I have this vague image in my head, but I haven't found the book yet. I want to say that it was a one-word title, the name he wanted to give to his creations. I only made it a few chapters in. There were at least three of the "bag guy" ones and I think one that was more benign. I remember reading a bit of it and getting Gremlin vibes off of it.
Comment: Aw man... this one is like on the tip of my brain!
Comment: As per our current criteria, we don't close duplicates for being good matches unless there's indication of acceptance.
Answer: Per user45049's answer to a similar question, could this be Dragon Fall, by Lee J. Hindle?
It's described in an off-site question as being

....about a young boy who made dragon statues (papier-mache or maybe
  clay) and they came to life to attack him, etc. Of course the grown-ups
  don't believe him, etc.
Comment: Thank you, Valorum. I should have thought to add an answer. I don't think Dan is coming back, though...
Comment: @FuzzyBoots - No worries. Since I closed it, it only seems right for me to make the effort to actually answer it.


Goodness of Fit Test for Logistic Regression with small n_i

Question: I would like to test how well my model fits the data. The response is binary and the Chi-Squared Test cannot be applied for the residual deviance because the $n_i$ are $1$. To use the Chi-Squared GOF Test, the $n_i$ need to be $\geq 5$. What's an alternative method can I use to test for goodness of fit?
Answer: First some comments on the assertions you made about chi square:
(i) The rule of thumb applies to the expected counts
(ii) That (quite old) rule of thumb is too restrictive; the chi-square approximation is usually fine if some categories have substantially lower expected values than 5.
What test might be done depends on what null you're testing against what alternative but I believe I understand - I take it you're interested in testing the model fit against the saturated model.
If you're fitting your logistic regression using GLM, it should provide you with a deviance test (also based on a chi-square approximation) which may be the goodness of fit test you're after. This corresponds to an asymptotic likelihood ratio test.
(The individual n's don't matter as much as the overall degrees of freedom.)
e.g. in R, see the examples under ?glm and ?anova.glm


Will deleting Clash of Clans on an old device affect progression on a new device?

Question: My sister transferred her Clash of Clans to her new iPhone. Now I have the old iPhone. I want to download and play Clash of Clans. Will her Clash of Clans be deleted from her new phone if I delete her Clash of Clans on the old phone?
Answer: You can delete Clash of Clans from the old phone and it won't affect Clash of Clans on the new phone.
You should create your own Game Center ID to play on the old phone. This will ensure your games don't interfere with her games. See http://support.apple.com/kb/ht4314 for steps to create a Game Center account if you don't know how to do this.


Integration tests start spring for every test

Question: My application is a spring-boot application with maven. It starts spring-boot for every integration test when I run mvn clean install
Answer: I found the peril after hours of googling and investigation.
It is because of the configuration of the maven-failsafe-plugin. The reuseFork is false in my pom.xml. I resolved the situation by removing the reuseFork(It is trure by default).
LOL.


Implementation of PCA algorithm for reconstruction of data(images)

Question: I'm learning the theory and implementation of PCA algorithm in the book 'Mathematics For Machine Learning' and finishing the official tutorial notebook in https://colab.research.google.com/github/mml-book/mml-book.github.io/blob/master/tutorials/tutorial_pca.ipynb.
Taking an encoder-decoder perspective, as the figure  shows, the algorithm could be formulated as a linear, lossy auto-encoder. Specifically, the centered data matrix $X\in \mathbb{R}^{D\times N}$, where $N, D$ are the number of samples and the sample dimension respectively. The encoder part is:
$$
Z=B^TX\in \mathbb{R}^{M\times N}
$$
where $B\in \mathbb{R}^{D\times M}$ is constructed by the $M$ eigenvectors as columns corresponding to the $M$ largest eigenvalues of covariance matrix $S=\frac{1}{N}XX^T$. And the reconstruction data by the decoder are:
$$
\hat{X}=BZ=BB^TX\in \mathbb{R}^{D \times N}
$$
So the projection matrix is $P=BB^T$.
But in the official implementation/solution of the tutorial in https://colab.research.google.com/github/mml-book/mml-book.github.io/blob/master/tutorials/tutorial_pca.solution.ipynb, it calculates the projection matrix as follows:
projection_matrix = (B @ np.linalg.inv(B.T @ B) @ B.T)

and the reconstruction matrix as:
reconst = (projection_matrix @ X.T)

And this corresponds to calculating the projection matrix as follows:
$$
P=B(B^TB)^{-1}B^T
$$
instead of $BB^T$.
The only difference of the implementation here is that the data matrix is transposed as opposed to the formulation in the book, so $X\in \mathbb{R}^{N\times D}$.
So I'm confused by the way the tutorial calculates the projection matrix. Can anyone give some explanations on this?
Answer: Since B has a D*M dimension then Bt (B transposed) will be of a M * D dimension, P will have a D * D dimension multiplied by X which has a D * N dimension, X¨ will have a D * N dimension, same as X.
Bt @ B is the covariance matrix.I honestly don't know why did they insert it in the middle and change the formulas, but the formulas are valid


Connecting WiiU Minecraft and an Android

Question: My kids want to both play Minecraft with their cousin in another state at the same time. The problem: 2 kids, 1 Wii U. Can I somehow connect a tablet to the WiiU platform so both of my kids can play with their cousin?
Answer: I'm not sure where you get your information.  I play the Wii U with both of my children, the only thing you need are additional pro controllers.  The standard wiimotes WILL NOT WORK.  Then you go into settings in Minecraft and select multiplayer split screen.  The Pro Controllers run $60, they are the same layout as the Wii U game pad minus the touchscreen.
Answer: I don't believe there is a way, in fact i'm quite sure that the only way for them to play together is on these four consoles:the Xbox360, the Xbox1, the Ps3, and the Ps4. I believe that that is it.
Answer: Unfortunately, you cannot connect Pocket Edition (Android) Minecraft with the Wii U version.  Each version of minecraft is separate from the rest.
The only option would be to have two Wii U consoles and connect the two over Nintendo Network (the Internet).

You can, however, play splitscreen on the Wii U version.  You will need an HDTV, the Wii U Gamepad, and a Wii U Pro Controller.  Other peripherals such as a Wiimote with an attached Nunchuck or Classic Controller will not work.
First, start up Minecraft and load a world.  Then, on the Wii U Gamepad, touch the icon in the bottom right corner of the screen. It looks like a Gamepad with an arrow pointing to the TV.
Once you touch that icon, the Gamepad's screen will show a grass block on a dirt background.  Then, pick up the Pro Controller and press A then Start (or +).  Minecraft will then show a Mii selector.  Select the Mii to play with, then press A and you will be playing in splitscreen.  The Wii U version supports up to 4 players in splitscreen.
Answer: You can use a Gamepad and a Pro Controller in split-screen if you have a HDMI connection to your TV and a HD tv (so 720p or higher).
Comment: I'm  not really seeing how this answers the questions at hand.
Comment: Considering the question is about two people in different states, telling how to play splitscreen really doesn't help.


Apple Push Notification Service Limit

Question: Does apple have a limit on how many pushes can't be sent through APNS at once or in one day?
Answer: Apple Push Notification Service is not limited by the number of notification to send.
Answer: @Sam I had the same question and needed some written evidence about APNS being free to be demonstrated to the client. After failing to find any such declaration on the official site, I had written a mail to Developer Support and the crux of their response was "currently its a free service". So go ahead and send as many notifications as you want :)

Apple Push Notification Service Limit


Automatic vertical alignment of a single float on a dedicated page

Question: In my large latex document, I have some figures which take a considerable height of the page (80-95%). Latex puts each of these figures alone on a page, aligned on top. I would like to have each figure aligned vertically to center. Is that possible, and if so, how? :)
Comment: As the answers tell, centering is the usual behavior; however it's the whole block (figure and caption) that's vertically centered.
Answer: I'm curious which documentclass you're using, as "normal" behavior (as defined in the LaTeX kernel file latex.ltx) is to center the float vertically on a floats-only page.
If you need to get the float to be centered on a floats-only page, you should add the following instructions to your preamble.
\makeatletter
\setlength{\@fptop}{0pt plus 1fil}
\setlength{\@fpbot}{0pt plus 1fil}
\makeatother

To have the figure/table be aligned at the top, you would delete the plus 1fil after 0pt in the instruction setting the length of the \@fptop variable.
By default, LaTeX will place a large float on a page by itself if the float's height exceeds 50% of the parameter \textheight. To change this threshold to, say, 0.75, you should issue the command \renewcommand\floatpagefraction{0.75}. Happy TeXing!
Comment: This does not answer the OP's question, in my opinion, he/she is only interested in a vertical centered solution (not top-aligned) *and* there was no mention of horizontal centering.
Comment: @Werner -- Yes, I initially misread the question, and have revised it since then. :-)
Comment: Consider using `\@dblfptop` and `\@dblfpbot` for two-column floats in two-column documents.
Answer: The [p] float placement specifier puts the float (figure or table) on a page of its own, vertically centered. The following MWE illustrates that:
\documentclass{article}
\usepackage{lipsum}% http://ctan.org/pkg/lipsum
\begin{document}
\lipsum[1-2]
\begin{figure}[p]
  \centering\rule{0.8\linewidth}{0.5\textheight}
  \caption{A big figure}
\end{figure}
\lipsum[3-10]
\end{document}

Note that by specifying the optional [p] parameter to your float, only that float will appear on the corresponding page.
Comment: I'm using "book" documentclass, with a lot of packages, most of them are recommended by our print service. Indeed, after your pointer (fptop) I started looking, and yes, there it was --- forcing top alignment.
Comment: I think the OP's issue is that his/her floats on floats-only pages are aligned along the page's top margin instead of being centered vertically. This must be happening because he/she is using a document class or some package that overrides LaTeX's default setup of centering the float vertically on a floats-only page. Will using the `[p]` placement specification solve this lack-of-vertical-centering issue?
Comment: @Mico: It may if they still include the figure inside a designated **float**, since they abide by the regular optional parameter for placement convention. However, if the documentclass provides a new **environment** (not a float), then neither of our solutions will do the trick; your's hooks on float-related spacing.


Magento 2 , How to remove the loader for every page load?

Question: After loading every page , I am getting loader and hiding . I want to remove that loader for every page , the loader html is loading after Body tag as follows

Please wait...

I have checked all files and settings still unable to find from where these loader is loading. Please help me resolve this.
Answer: You can remove it using CSS
.loading-mask {
    display: none;
}


HTTPS connection failure when trying to open AWS console

Question: I have some very strange problem with connecting to AWS Cloud Console on my Ubuntu 18.04 host. When I open https://aws.amazon.com/console/, I can click on the "Sign in" button at top right, the URL redirects to https://console.aws.amazon.com/console/home, a loading spinner appears, but then URL changes to https://eu-west-1.console.aws.amazon.com/console/home?region=eu-west-1 and the browser shows connection error.
In one case the error (on Firefox) is "Secure Connection Failed. An error occurred during a connection to eu-west-1.console.aws.amazon.com. PR_END_OF_FILE_ERROR". But then for a subsequent unsuccessful attempts sometimes the error is "The connection has timed out. An error occurred during a connection to eu-west-1.console.aws.amazon.com. PR_IO_TIMEOUT_ERROR"
The problem is weirdly universal: the failure is in Firefox, Chrome, and even in Chrome in Windows VM, and Firefox in Linux VM on this Ubuntu host. Doesn't matter if I clear cache and cookies, or use private/incognito mode. If I try to access the AWS Console from another computer in my network, there are no problems (tested on Windows 10 and Ubuntu 19.10). I have no problems connecting also from this computer, when I boot it in Windows 10 (dual boot). So I figure that is something to do with how the Ubuntu 18.04 host processes some specific SSL network traffic.
My system time is up to date, synced with time server. I haven't encountered problems with any other https hosts. The console opened just fine about 4 days ago, so this is a pretty recent behaviour.
Update: If I go ahead and manually change the failing URL from  https://eu-west-1.console.aws.amazon.com/console/home?region=eu-west-1 to https://eu-west-2.console.aws.amazon.com/console/home?region=eu-west-2, then the console opens, but at London region. If I then try to switch to Europe (Ireland) eu-west-1 region from the region dropdown at top right, I get the "The connection has timed out" error, as previously. The sad thing is that my EC2 instances are in eu-west-1 region, where I have trouble connecting to. I wish this was the problem at AWS, but it most certainly is not.
Comment: [Another report of the same issue](https://askubuntu.com/questions/1247182/problem-loading-page-console-aws-amazon-com)
Answer: This solution works for me:
Edit the file /etc/resolv.conf so that is has this additional line:
nameserver 22.214.171.124

Save the changes.
Now, clear cookies in your browser.
If it does not work restart your system and repeat the steps again.


If there any option inside sharepoint document libraries to allow multiple users to work simultaneously on the same .xls file tabs

Question: We are working on a sharepoint 2013 team site. and inside the document library we have a .xls file which contain 5 tabs. so now oor users are asking if multiple users can work simultaneously on the same .xls file tabs ? Now based on the available options within the document library i did not find any thing related to this.
Answer: This depends a bit on the setup.
The filetype you mentioned is not ideal. You should check and upgrade to xlsx.
Besides that it depends on your Version of Excel. WAC (Word/Excel Online) allows you to coauthor and also the latest Versions should allow it. So if you have an office web app farm with your SharePoint it should work. If not you would need a current excel Version. Since you mention SP2013 I put current in bold ;)
A bit more information can be found here:
https://support.office.com/en-us/article/Document-collaboration-and-co-authoring-EE1509B4-1F6E-401E-B04A-782D26F564A4
They keyword to search for more info would be co-authoring.
[edit]
One of the key points is that not all versions of office support coauthoring of excel files. For SP2013 you need the office WAC server
Here is an overview link:
https://docs.microsoft.com/en-us/SharePoint/governance/co-authoring-overview
Audience: IT Professionals
Use the co-authoring feature in SharePoint Server or SharePoint Online to enable multiple users to work on a document, at any time, without interfering with each other's changes. Co-authoring removes barriers to server-based document collaboration and helps organizations to reduce the overhead associated with traditional document sharing through attachments. This functionality requires no additional server setup and is the default state for documents stored in SharePoint Server and SharePoint Online. Co-authoring functionality is managed by using the same tools and technologies that are already used to manage SharePoint, helping to minimize the impact on administrators.
Office provides co-authoring functionality for Word, PowerPoint, OneNote, and Visio. If you are using SharePoint Online or have SharePoint Server configured to use Office Web Apps Server, users can also co-author documents in Word, PowerPoint, Excel, and OneNote Web Apps.
Hope that helps
Comment: updated post - yes it is possible, but you need to use a very current excel or use the office servers to do so
Comment: i can convert the file from `xls` to `xlsx`, this should not be a problem... now inside our on-premises farm we do NOT have office web app farm configured... so not sure what will be our current situation? second point when we talk about co-authoring this can only be done per excel tabs?or within the tabs themselves ?
Comment: now i think there is a miss-understanding between my question and your answer, now i search for SP co-authoring in SP 2013  and i found this official link https://docs.microsoft.com/en-us/sharepoint/governance/configure-versioning-for-co-authoring but this talks about setting the versioning + check-in/check-out options.. but my question is about if there is a way to allow let say 2 users to edit the same `.xls` or `.xlsx` file at the same time, where each user will be modifying different tabs... this is not related to versioning and check-in settings
Comment: thanks a lot for your reply and help. you have put my on the right track, now in our case we have SP-2013 on-premises withOUT WAC. and we configured the document library to open the document inside the client application,, so seems not having WAC with SP2013  will not allow me to have co-authoring for the excel sheets (regardless of any settings inside the document library) is this correct ?
Comment: second point now on another sharepoint online farm, i i uploaded the same `.xls` file to test co-authoring in SP online, and i open the excel sheet inside excel online using 2 users, but i got this error "sorry we can not open the worksheet in the browser because it uses unsupported features".. so seems for our case we can not have co-authoring inside our SP2013 since we do not have WAC + we can not have co-authoring for this excel sheet inside SP online, since the excel sheet has unsupported features.. are my above 2 points valid? thanks in advance for ur help...