Using wormwood as a bittering agent: How much and when?

Question: I have a beer that I going to brew, it is technically a gruit, b/c I am not going to use any hops.  The original beer recipe (an American Hefe) calls for only one ounce of 4-6% alpha bittering hops and a 60 minute boil.  The OG will be between 1.045 - 1.055.  About how much wormwood should I add and how long should I boil?
Comment: We made some absinthe with Wormwood in college, and it was extremely, extremely bitter. Just an FYI.
Comment: @PJ thanks for that comment, I'm trying to make something that isn't over the top bitter as you can see from the 1 oz of hops at 4-6% alpha
Comment: We also extracted it for months and months in high-proof liquor. I was pouring lemonade powder on my tongue for 5 minutes to make the bitter stop hurting.
Answer: There are no good bittering values ascribed to the many herbs used to design gruits.  It comes down mostly to experimentation and the expectation that you won't make the best gruit on the first pass.  I'd suggest looking for recipes for gruit with wormwood for guidance.  Or start with a one gallon batch for test runs.
Answer: You could make two teas with equal volumes of water and equal mass of wormwood & hops in each one, and compare the bitterness levels.   Try and get some other people to compare them as well, if you have willing tasters around.   You may have to make a few batches to really get it figured out.   If you have a few different types of hops, you could make several batches, so you could have a better basis for comparison.   More bitter than Saaz doesn't really mean that much.   More bitter than Columbus, and you know you really don't want to use much at all.


How to disable screen saver and power management in linux by command line?

Question: Is there a command line you can run that can enable in-habitation, disabling computer going to screen saver, sleep?
Answer: The xset command controls a number of parameters of the X server (the part of the system that provides a graphical display with windows), including its built-in screen saver and blanking ability.
xset -dpms s off

If you're using a third party screensaver, it might still be triggered.
Answer: Ubuntu Forums suggests the following:
gconftool --type int -s /apps/gnome-power-manager/backlight/idle_dim_time ***time***
gconftool --type int -s /apps/gnome-power-manager/timeout/sleep_display_battery ***time***
gconftool --type int -s /apps/gnome-power-manager/timeout/sleep_computer_battery ***time***

Answer: When using LXDE (e.g. for running chromium in kiosk mode) you can remove the screensaver by editing ~/.config/lxsession/LXDE/autostart and remove @xscreensaver -no-splash.


is there a faster way to copy select vertex position from one side to another

Question: Lets say I am making an object with two sides that are symmetrical, lets say over the X-axis, and I need to realign some vertices to match changes I have made on only one side. then I will go to the first vertex, copy the x-coordinate, paste it into the corresponding vertex on the other side, and put a minus on before hitting enter. Then I will do the same for the Y and the Z-axis, except for the minus. Then I will do that for every single vertex that needs changing. This is boring and takes extra time that I feel I shouldn't need to waste.
now my question is this. Is there a faster way to do this? Can I somehow use something like the symmetrize function for Armatures on a mesh? and also bonus question is it possible to do this to only the selected vertices, and not all of them?
Answer: select your vertices -> Mesh > Mirror -> interactive mirror


How to change Outlooks CTRl+Backspace behavior?

Question: Every single application I know of, deletes the last word until the space before that word when pressing ctrl+backspace. Outlook (and perhaps other Microsoft applications) are the exceptions to that, as it includes that space before the deleted word. Is there any way to adjust Outlook's behavior to be more according to the aforementioned convention?
Answer: Are you using Outlook desktop client? If so, please make sure you have upgraded your Outlook to the latest version.
I tested in my environment Outlook 365 and found that Outlook also deletes the last word until the space before that word as other applications do.
Corrupted Outlook template file may cause issues like this. Please try to rename the NormalEmail.dotm file and restart your Outlook client to see if there is any difference. File location: drive:\Users<username>\AppData\Roaming\Microsoft\Templates.
Comment: Yeah, I just tried again and now it works properly. I'm very confused. I'm unable to reproduce the issue anymore. Problem solved, I guess.


Is it possible to boot a Raspberry Pi 4 from a GPT USB-connected disk?

Question: Similar question was asked here, but the answer is out of date and I don't have enough reputation to ask in a comment. I know it's possible to boot a Raspberry Pi 4 from USB with the latest firmware update, but does it still need to be on an MBR disk?
Answer: Yes, it is possible, I just did it a few hours ago, all with the latest Raspberry Pi OS Lite image.
I just created a GPT on the external disk, a 256MB partition formatted with vfat and labeled boot, and an 64GB one formatted with ext4 and labeled rootfs, just like the SD card. Then I copied all the files from the SD card boot partition into the disk boot partition, and did the same thing with the rootfs partitions. I choose 64GB as a personal choice. I wanted to have a root partition and a data one. You can probably fill the disk with the root partition.
By the way, you will have to update your /boot/cmdline.txt and /etc/fstab files, as your partitions will have different PARTUUID values. Also you have to change the boot order with raspi-config.
I recommend you set up /dev/sdX values in those files and then boot the raspberry and update the values with the right PARTUUID values. I tried to use the PARTUUID values I got when the disk was attached to my laptop, but they are different, for some reason.
Comment: Note you *have* to use PARTUUID (as opposed to UUID) since stock Raspbian doesn't use an initrd.
Comment: I can also confirm I am able to boot Raspberry Pi 4 from a USB attached disk that uses GPT partition table
Answer: No the Pi will only boot from a FAT partition on a MBR partition table.
I believe it may be possible with a modified image with GPT support in an initramfs.
Answer: The awnser of @sildur is correct. Here is an a little bit more in detail what I had to do to get debian on a pi cm4 to boot on a fully usable 4TB m.2 ssd.

Have an MBR Drive where the os is flashed and ran at least one time.
Copy all data while preserving attribute to your local machine

cp -rp ...dist/bootfs/* ./bootfs
cp -rp ...dist/rootfs/* ./rootfs

Use GParted to create an gpt partition table.
Use GParted to create 3 partitions:

bootfs (fat32 with 4MiB storage free before that and 512MiB in size)
rootfs (ext4 with all the space that os and programms need)
(optional) nameAsYouWant (ext4 the rest of the space available)

Copy all the data back to the disk

cp -rp ./bootfs/* ...dist/bootfs
cp -rp ./rootfs/* ...dist/rootfs

Change ...dist/rootfs/etc/fstab and ...dist/bootfs/cmdline.txt PARTUUIDs matching to the PARTUUIDs from blkid (Use PARTUUID not UUID!) You should need to adjust 3 variables in total.

Please adjust the mounting points to your needs: ...dist/bootfs and ...dist/rootfs.


what does the pie symbol mean in macOS finder?

Question: could someone explain this symbol? The files are on a AFP share which is mounted.
Answer: The pie symbol indicates that the element is being uploaded or downloaded to/from a server. Those elements may not be available locally.
The grayed part of the pie represents the percentage of data already transmitted so in your case as this part is very narrow it means that for each file the update has just started.
Answer: The pie symbol is a progress indicator that indicates the manipulation of a file of some kind. Since you are taking about Apple Filing Protocol (AFP), you are most likely referring to either:

Transferring from internal to network
Copying from network to network

It could also be:

Transferring from a drive to another drive
Transferring from network drive
Copying a file
Safari (and other) downloading from the internet
and many more…

As @LouisLac said, this could also be uploading or downloading from iCloud.
Answer: The colour of the pie icloud uses is indeed somewhat confusing.
While I was looking at it as my files were synchronising I understand now:
Full black means 100% sync.
And white means the amount left to sync.

For example right now my drive is around 90% sync. And 10% files are left, waiting for sync on the icloud server and devices.


Confusion regarding Virtual Box and a Linux Distros

Question: I was trying to learn Linux, and a guide told me to use Virtual Box and CentOS since CentOS is similar to Red Hat. However, I encountered some CPU issue with my machine, so I wanted to try running a different distribution to learn from. I downloaded Ubuntu Kylin, and it won't appear in the Virtual Box tool when I search for it. I believe that it is because Kylin is a Disk Image, and CentOS is in the correct format of a Virtual Disk Image. Is there a simple way to convert the Disk Image without installing some sort of program that I'm unfamiliar with?
Answer: If you can find a Virtual Machine image (ovf or ova) for CentOS, you can 'Import Appliance' and follow the steps.  However, most people download the CentOS ISO CD image, then create a new Virtual Machine in VirtualBox. Next you would "load" the ISO into the Virtual Machine CD drive, and on boot go through the OS install process (installing from the ISO/CD to the VM hard drive in Virtual Box).
Here's a thread with links to parts of the process
Comment: I've actually purchased a new laptop with proper specs so that I can run CentOS. Thank you for all the help!


Can a HSDir see visited onion url's?

Question: Is it possible that a HSDir can see visited onion urls?
If I make a onion website and my friend visits it could there be a way that someone can capture the url he used? (the .onion url).
Answer: Yes, currently HSDirs can see the looked up .onion hostname. This does not include the full URL but just the .onion hostname. Proposal 224 (ticket #12424) will fix this issue. See also #8106.
If you want to make the page accessible to your friends only the HiddenServiceAuthorizeClient option might be something that could interest you.
Comment: Simply by logging with for instance tcpdump?
Comment: tcpdump won't work since it only sees encrypted traffic but it shouldn't be hard to modify Tor to log the addresses somewhere.

Can a HSDir see visited onion url's?


What ever came of this proposal to increase the count of down votes?

Question: I came across this SO meta Q titled:Should the weight of downvotes be increased? that I believe Jeff Atwood asked. It ultimately got declined and was wondering if anyone knew the back story as to what happened and why it was declined.
Comment: Not sure why you posted here; people on MSO are more likely to know the history, if anybody does
Comment: Was a little intimidated to ask this over there, I thought maybe one of our mods knew why.
Comment: If you scroll down far enough, there is a checked answer (from Jeff Atwood himself).  Reason #1 is parallel to mine ("Downvotes go from being cosmetic and psychological to weapons of war").
Answer: I don't have the answer but I do have an opinion (TL;DR -> Positive reinforcement is a better motivator than fear of punishment).  It's interesting that:

When we started Stack Overflow, we wanted to make sure that downvotes
  were more of a visual and psychological motivator than a punitive
  action.

That seems like a wise choice to me, because it emphasizes that what's significant is the question's score, not how many points it did or did not generate for the user.  The critique that:

downvotes don't quite carry enough... -5 downvotes and +1 upvote (for
  sympathy) yields zero points overall

Sort of turns this on its head and implies that what's most important is the number under your name.  Of course, it's somewhat important, which is why this is even a question, but it should not be the ground of the whole scheme.
Right now your user cred is mostly about people giving (or not giving) you points.  If the game became more about people taking points, my feeling is this would just attract more negative behavior, grudges, etc.1  It's one thing to be told you are wrong, it's another thing entirely for someone else to be able to arbitrarily penalize you for it.
Also, I don't want to be a cop, and if I knew that someone might be sitting there going, "Oh that sucks my points are down", then I would be less inclined to down vote -- I'm already disinclined as it is.  I don't want to punish people, I just want to draw their attention to their mistakes. Consider on U&L:
<code>goldilocks upvotes cast 658 down 24
slm upvotes cast 5831 down 104
</code>
Looks like I'm relatively stingy, :( hmmm...food for thought...better get out there and vote...anyway, I imagine what would happen if you changed the penalty would be some people would downvote less and some other people would downvote more.  Betcha.  Would that be better?
Finally, downvotes should reflect more on the anwser/question than the answerer/questioner, which they do.  Again, gaining points is what creates the game and encourages us to try and do a good job of it, but losing points can only discourage people from trying.
1 As is, making the penalty minor and including a small cost to the downvoter probably discourages "retribution votes".  If downvotes were more serious affronts to the user, you'd see more people getting serious about retribution.
Comment: Sorry I didn't mean to imply that I thought changing the voting ratios around would solve this particular problem, I was researching what to do and came across this Q&A and was more curious than anything whether this went any where or not. I'm glad that didn't change the ratios since I don't think that would've solved anything, just created a whole knew set of problems.
Comment: I 100% agree with your synopsis. Seems like we're on par with each other; I have roughly an order of magnitude more votes in both categories, but we're roughly the same run rate of up's to down's, which is exactly what we should see within the site. The only reason I asked about this was that I've noticed some users here using the same tactic on SO where they provide 1-2 sentence answers that show little effort to me, so I was curious what options we as a community had at our disposal. I like you don't like to DV, and I feel funny DV, an A that's kinda correct, but lacks details.
Comment: These 1-2 sentence answers are a consistent pattern on SO where ppl are trying to throw as many A's out there to generate UV's. This site has seemed pretty immune to this tactic, and I'd aim to keep it that way, but I've notice several of these high rep'ed SO users driving by here on occasion.
Comment: Well -- the world ain't perfect, and attempts to push it further toward (some vision of) perfection can have unintended consequences ("throwing the baby out with the bathwater" and all that).  I realized writing this that I should *upvote* more, which of course doesn't discourage the machine gun answers but hopefully encourages something else.


Why isn't the asteroid belt affected by Jupiter's gravitational field?

Question: Jupiter's mass is just about a 1000th of the sun's and the asteroid belt is slightly closer to Jupiter than it is to the sun.
If the heavier the object, the more curvy space is around it, why isn't the asteroid belt's movement more turbulent owing to the effect of both Jupiter and the sun?
Comment: https://i.gifer.com/4EfK.mp4 Looks pretty affected to me
Comment: To be quite honest, what made you think that they **aren't** somewhat affected by Jupiter?
Comment: @wireman: Consider in the future when phrasing questions to not assume that the laws of physics are being broken in your question. "How are asteroids affected by Jupiter's gravity?" phrases the question in a way that does not make the non-physical suggestion, as your question does, that asteroids are somehow immune to Jupiter's gravity.
Comment: @mattdm: All the asteroids in that graphic are outside the orbit of Mars.
Comment: @JollyJoker I'm not an astronomer, but as I understand it, that's not the asteroid belt, which exists in a ring outside the orbit of mars (and not depicted in that animation).
Comment: @mattdm: I misunderstood the thrust of your comment. Yes, that diagram only shows asteroids whose orbits are enormously perturbed by Jupiter in a way that keeps their unusually-shaped orbits stable. You are correct that there are a great many asteroids that do not have this property, and that they are distributed in a ring more or less immediately outside the orbit of Mars.
Comment: @JollyJoker: Those are the Hildas (red) and the Trojans (green), not the main-belt asteroids.
Comment: @Eric Obviously. But I mean in the "empty" area on the graphic.
Comment: Isn't everything affected by everything else's gravity? In the entire universe?
Comment: And to clarify my previous comment: the individual orbits of those asteroids are more or less ordinary ellipses; they are not triangles. Jupiter perturbs those orbits such that the perhelions of those orbits correspond to the middles of the triangles. I should have said unusually-distributed orbits.
Answer: The asteroid belt is affected by Jupiter's gravity.
There are stable orbits inside of Jupiter's orbit. Jupiter's Hill Sphere has a radius of 53 million km. If you are more than 53 million km from Jupiter, then the Sun's gravity dominates and you can orbit the sun. But Jupiter orbits 780 million km from the Sun, so there is plenty of space between Mars and Jupiter for asteroids to have stable orbits.
As they pass Jupiter on their orbit they will get first a pull forward, and then a pull back but as these pulls happen at different locations on each orbit they tend to cancel out and result in effects like precession of the asteroid's perehelion or periodic variations in eccentricity. These effect act on the Earth and other planets too.
However if the time the asteroid takes to orbit the sun happens to be an exact fraction of the time that Jupiter takes, then it might receive the same pull at the same location. Resonant orbits like this tend to be unstable. The asteroid will be nudged out of the resonant orbit and into one that doesn't match up with Jupiter.  This creates the Kirkwood Gaps in the asteroid belt.

Source
Comment: Well if there was a 17:5 ratio, you would only get an repetition after 85 orbits. That isn't enough to cause a large gap, at the other 84 orbits there is another tug, but those are all in different directions
Comment: Very interesting, thanks! I wonder why orbital resonances only occur at these 'simple' ratios. For the 2:1 example stated in the source link you provided, it says _Once every two orbits, the relative positions between the asteroid and Jupiter will be the same, and the repeated tugs from Jupiter at this point will change the orbital elements of the asteroid_. However, I'd imagine this similarity of relative positions would occur at any ratio? (and not just simple ones)
Comment: In fact, I think you'll probably find that those other unmarked dips in the curve probably also correspond to slightly less simple ratios.  E.g. I'd guess that dip between 3:1 and 5:2 might be around 8:3.  The one between 7:3 and 2:1 might be 11:5.  The gaps are deepest where the ratios are simplest because those have more effect.  (Note that even the 7:3 gap is less dominant than the 5:2, which in turn is less than the 3:1 and 2:1 gaps.)  Harmonics are fun.
Comment: Might add that some of the asteroids orbit on Jupiter's orbit at the Lagrange points P4 and P5 ... in all .. Jupiter structured the distribution of asteroids in the belt - and prevented them from forming a small planet (although the whole mass is less than that of our Moon if I remember correctly)
Comment: @wireman yeah, every fraction is a resonance, but the strength of the effect is inversely proportional to the least common multiple of the numerator and the denominator. Or maybe its square, even.
Comment: There are also the [Hilda Asteroids](https://en.wikipedia.org/wiki/Hilda_asteroid), which are in a 3:2 resonance with Jupiter and reach aphelions coinciding with the passage of Sun-Jupiter L4, L3, and L5 in succession.
Comment: @eagle275 Jupiter's Trojans *etc*: https://en.wikipedia.org/wiki/Jupiter_trojan


Writing with RTL language inside of formulas in LYX

Question: I recently started using LYX and it's GREAT!
I have configured it for using Hebrew and everything works fine except I can't write in Hebrew inside formulas normally. In the equations it won't let me change language in lyx (even when I use \text) and if I do the forbidden act of changing the language in Windows it write from LTR instead of RTL. I wanted to know if there is a simple way to deal with this problem?
Thanks in advance for any help available!
Comment: Welcome to TeX.SX! You can have a look at [our starter guide](http://meta.tex.stackexchange.com/q/1436) to familiarize yourself further with our format.
Comment: What exactly should the result be? Suppose I have this in English: http://i.stack.imgur.com/pfvqF.png. What should happen in Hebrew? Are the symbols different? Do they get reversed? I'm not sure how you could mix LTR with RTL on one line, so I'm wondering if there are RTL systems of mathematical notation? Or...?
Comment: In Hebrew we write the math from left to right and the Hebrew from left to right. If I were to write the word "where" from your example in Hebrew ( "כאשר"), because Hebrew is written from left to right, it would write "רשאכ" the equivalent of "erehw" in English. Again that only happens when I change the language through Windows (which makes all sorts of problems and I've been told not to do). If I change the language through LYX it just throws me out of the formula.
Comment: Please help us to help you and add a [minimal working example (MWE)](http://meta.tex.stackexchange.com/q/228) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with `\documentclass{...}` and ending with `\end{document}`. [For one thing, some of us cannot just make up some Hebrew to experiment with. For another, it may matter how exactly you are typesetting the language.] I'm not sure, but I don't think that LaTeX can switch directions mid-paragraph. But I'm not at all certain of this.
Answer: When setting up typesetting Hebrew using XeTeX in Lyx, it is possible to write Hebrew inside formulas. The Hebrew will look reversed in LyX but will look fine in the output.
Comment: Is there a bug report with a minimal example for the incorrect LyX display? If not can you make one at http://www.lyx.org/trac ? We would like to correct the problem but without an example it is difficult.
Comment: I've updated http://www.lyx.org/trac/ticket/7207 with a minimal working example.


In a large extended family somehow only my sister was born in October. What are the odds of that?

Question: The are 45 people in my extended family.  Only my sister was born in October.  What are the odds of that occuring?
Answer: You're basically looking for what are the odds that all 45 people do not have October birthdays, so this should be fairly straightforward. Depending on how precise you want to get it. If we just ignore that months have different lengths, it would be:
$$\bigg({11 \over 12}\bigg)^{45} = 0.0199 \qquad{\rm or}\ 1.99\%$$
If we look at October having 31 days vs the other 334 days of the year (ignoring leap years) it would be:
$$\bigg({334 \over 365}\bigg)^{45} = 0.0184 \qquad{\rm or}\ 1.84\%$$
All of the above assumes that people are born in equal distribution throughout the year, but in reality they aren't. You could look at some census data to see which months have more births and which ones have less then come up with a way to weight it accordingly. I have a feeling you aren't looking for this layer of precision and are merely curious at an off-the-cuff answer.
Comment: Please state *all* the assumptions you have made in order to carry out these calculations.  One that is extraordinarily important is *independence* of birth months.  Then, please revisit your calculations, because they are inappropriate for the question: you should be computing the chance that one or fewer people were born in October, not that zero people were born in October.  You will get a much larger answer (around 9.5%).
Comment: I think, to make it even more exact, one also would need to incorporate the correlation. Say if someone was born on 1st of November, there is a chance, that he has a sibling born on the same day (e.g. twins).


Do you need to pay $100 a month for a Server when building a website?

Question: Do you need a virtual or dedicated Server when simply coding?
Would you be able to build a website from scratch from your on PC and take a Server only one day befor going live in Beta?
Comment: Look around and you should be able to rent some space (Linux *or* Windows) for more like $5/month than $100. No you won't have a dedicated (virtual) server to install whatever you like on, but for the great majority of purposes, it will do the job.
Comment: Cheers Carson. With the cheap "rent some space" option of a fiver a month you suggest, do you think I should worry about "privacy"? I mean, would I potentially risk sharing my coding with unwanted onlookers?
Comment: You are going to do that anyway, unless you host your own site. What's the difference between doing it doing development and when the site goes live? Just Google around for a reputable host. If you are still worried, minimize or obfuscate your code before uploading and lock down your databases (if you are truly paranoid, encrypt all data that you store in a database).
Comment: Personally, I always develop on `localhost` on my laptop anyway, for about 90% of the development process, before paying for a server. In my case, it's a bonus, in case I am somewhere with no internet access (yes, they exist ;-)
Answer: No
and yes...
Technically if you're very good you wouldn't need a development server — or any other remote environment. All your code would be perfectly platform independent.
Does this mean it's a good practice to follow? No! Go get a Slice or a Node and set yourself up with a small VPS. It's not $100 / month, and it will save you time developing.
Comment: Tks vm Josh. The Slice and Node links you posted are really useful and will look into that.
Answer: Depending on your target audience and a whole raft of other things have you considered cloud hosting? There are plenty out there that allow you to push from git and be live in less than a minute.
That said would I ever do this the day before going to beta? Hell No
Always be prepared and know your platform, but does that also mean you need to pay $100 a month for a server from day one? Of course not as well.
Comment: Sure, I am hearing you. Well it doesn't have to be exactly 24h before going Live; it could even be the last whole month of the 5 I've been coding...
Comment: Unless you need some specialized software, I'd definitely go for cloud hosting.  That's its whole *raison d'etre*, and not only will it scale if your app turns out to the The Next Big Thing, but it's pretty cheap if you only use one or two servers (like during your beta period).
Answer: You definitely want to take a server more than a day before going live - last minute problems are not fun. However your use of a day as an example is unfortunate as now no-one is answering the other part of the question.
Do you need a server from day 1 of your project? Depends. You want to be developing on an environment as close to your server as possible, to ensure that all bugs/problem are ironed out.
Trivial example; on Linux filenames are case sensitive, on windows they are not. This also shows up in MySQL Tables. So on windows, both
<code>require "Cats.class.php"
require "cats.class.php"
</code>
Will work. On Linux, that will error.
So, the question is, can you make your development environment as much like your live environment as possible? If yes, then you don't need a server from day 1. If there are major differences, a server may be wise.
But as another poster says, look at cheap VPS's - 100/month while developing may be overkill.
Comment: Come to think of it, 100/month for a just-launched-beta is overkill to, unless you have a guaranteed audience and you know it's going to be big :-)
Comment: Development might take between 4 to 6 months, so I agree on the teriminology you used "overkill". I'll look carefully into the "compatibility issue" you raised between the 2 "development" and "Live" environments. Cheers
Answer: Another option, besides getting a VPS, particularly if you are going to run your web site on a *nix platform, is to simply create a virtual machine and make a mundane "server" installation of your target platform, then deploy to it as if it was a remote server. It's not going to be perfect, and it will take a little more time setting up, but on the other hand the cost will be negligable, and you will get a very good feel for what is actually required on the server and how to set it up before going beta.
This isn't quite as much of an option if you are targetting Windows, because of the license cost, but even then it may be an option.
Comment: +1 for a virtual server.  Amazon just announced that it would support uploading of customer VM images to their infrastructure, so theoretically you could develop on a VM then upload the whole (debugged) thing and have it hosted in the cloud.
Answer: Go for a lower end box,and test it all you want,then you will see you can get so much more for $100/mo.
Comment: Will probably go via this cheaper route, cheers.
Answer: Yes, you could, but I wouldn't do it. There are too many things that can go wrong on a website (particularly one that is hosted by a third party) that leaving server configuration until 1 day before launch is fairly careless. The third party could be unreliable, could have trouble configuring the site properly, you could have account/login trouble in addition to difficulty reaching customer support. Tons of things can go wrong at the last minute that giving yourself a paid month of unused support/service is a worthy investment just for the peace of mind of knowing that when you want to launch you can launch.
If missing the launch date by a day or 2 due to these problems doesn't mean anything to you, meaning you can recover and it's no big loss, then save yourself the money and deal with the problems as they come. Almost all of the problems you'll encounter will be fairly quick fix problems, and any respectable third party hosting provider will be fairly reliable in supporting you rapidly if necessary. Worst case scenario would be a miss of about 3 days (if everything went wrong). If you can handle that kind of gap and $100 is a big deal, then save the money.
Comment: Well, that's exactly what happened after the first month of paying 100$ a month! The Server Provider, which claims a 24/7 support, turned unreliable: in fact, as you say, I had exactly the problem of being unable to reach customer support for 2 days in a row! Hence, I started asking myself why I was paying so much when perhaps I didn't need to... I shall postpone running the website (under construction for at least another 4 months) on my own Server when I really need to, perhaps just a month-ish before going Live in Beta. Cheers
Comment: @Dave - I would question $100/month for such hosting anyway. There are many hosting providers out there that offer a lot of resources for very little cost (and have proven track records of customer service). If I pay $100/month and I can't get someone on the phone the first time I call, I change providers.


PowerEdge 2900. Want to use as a SAS wiping server, and skip Raid configuration for each drive. Possible?

Question: I've got a Dell PowerEdge 2900 with 8 SAS slots in the front. I want to be able to load drives quickly without setting them up in RAID. We have a pile of about 50 SAS drives that need to be wiped. Is there any way to quickly get them seen by the OS to wipe them without initializing them through the RAID controller?
Comment: damn I was looking forward to hitting them with a hammer..
Comment: are you talking good old fashion scsi disks or are these really sas disks, if old fashion scsi then I'd just take a hammer to them.
Comment: Ah, they are in fact SAS.
Comment: So thei 2900 will be hooked up to a working server of some sort right, you can with dell poweredge scripts create a bunch of single disk arrays then run a wiping tool on these individual arrays.
Answer: I assume you're trying to blank these drives for some kind of "certified" data destruction?
If that's the case bashing them to bits with a hammer is the fastest (and most fun) method.
A close second is using a high-power degaussing wand (or machine), though this will likely render the drives unserviceable for any future use.

If you want to reuse the drives again you're probably in for a long process no matter what you do.
I can think of two options to speed things up:

You can disable the RAID controller on PowerEdge systems, but I'm not certain the PowerEdge chassis would still allow the drives to "hot swap" in that configuration (you'd have to shut down to swap the disks between blanking runs).
You could also simply create an array, blank it, then repeat the process until you're out of disks -- This should be adequate for simple zeroing-out of the drives (they'll have RAID metadata on them, but the rest of the volume will be zero'd out and not trivially recoverable).

(In both cases you'd need some kind of boot device - USB drive, Live CD, etc. - to actually run your erasure software from, otherwise you'd be going through an OS install every time.)


Meaning of Timing valve is open

Question: What is the meaning that Timing valve is open? A local mechanic told me to change the timing valve to fix P0018 code. But he is not sure if there are othern hidden issues. Is it possible that Timing valve is open due to a stretched timing chain?
Comment: p0018 is a cam crank correlation code. it could be cam timing is off or that a cam phasor/actuator is stuck. what's the car/engine etc...?
Comment: sorry for my late reply. It is hyundai sonata  3.3L engine.
Comment: Are you sure that the valve is open and not the crank position circuit is open (i.e. open circuit)?  I take it that the car does not run in the state it's currently in?
Comment: The car runs but it shakes badly at idle when in drive mode. When the car is in neutral mode, shaking stops or reduces significantly.
Answer: The P0018 code is related to your cam and crank showing incorrect timing
There are two sensors involved in this error.

Cam Position Sensor
Crank Position Sensor

These two sensors detect the angle of rotation of each shaft and when they fall out of tolerance in timing, you get this error.
There are multiple reasons why your crank and your cam(s) may be out of time.

Timing chain/belt has stretched beyond service limits and has taken the two shafts out of time due the amount of stretch the timing chain/belt has undergone over time.
Your timing chain/belt has skipped a gear tooth or cog taking the cam and crank out of synchronization
A bad cam or crank sensor or the wiring to either sensor

Symptoms
Some of the symptoms of an engine that has a legitimate timing issue between the crank and the cam.

Runs very rough
Only runs at certain RPM's
Doesn't run or start at all
Comment: Would you suggest  OP to take the car to a different mechanic? If so, it will help to make this clear in the answer.
Comment: @rana    I think whether or not the OP wants to DIY the fix or take it to another mechanic is up to the OP.   I do not know the OP's skill level and don't want to assume the OP wants to goto a mechanic or otherwise.  I believe that decision is subjective and out of my realm.  IF the OP would like to ask a question on how to time the engine or test a sensor, that might be the next step for them. OR.....they goto another mechanic.  The original mechanic did indicate a timing issue.

Meaning of Timing valve is open


Can I pray beside a Flag?

Question: Can I pray salah beside my flag, The flag is not infront of me but it is about 2 metres from where I pray is it allowed or do I have to remove my flag? The Turkish Flag, Moon and star
Comment: What flag? Some flags have images of living things. According to some it is makruh to pray with an image in the room, even if it is at a side, ref: https://archive.org/details/FPmfkmfk/mfk12/page/n125/mode/2up?view=theater
Comment: It is the turkish flag
Answer: In Islam, the act of performing Salah (prayer) is a sacred and deeply spiritual practice. While there are specific guidelines regarding the cleanliness of the prayer area and the avoidance of distractions, there isn't a direct reference in the Quran or Hadith that explicitly mentions flags. However, we can derive some general principles from Islamic teachings to address your question.

Minimizing Distractions: The primary objective during Salah is to establish a strong connection with Allah (God) through focused worship. The Prophet Muhammad (peace be upon him) emphasized the importance of minimizing distractions during prayer. For example, in Sahih Bukhari, there is a hadith that states, "When you stand for prayer, you should not spit in front of you, because in prayer, you are talking in private to your Lord." This illustrates the need for a distraction-free environment.

Cleanliness of the Prayer Area: It is essential that the area where you pray is clean. The Prophet Muhammad (peace be upon him) said in Sahih Muslim, "The earth has been made for me (and for my followers) a place for praying and a thing to perform Tayammum (dry ablution) when water is not available."

Given these principles, if the flag is placed about 2 meters away and is not directly in front of you, it may not necessarily violate the guidelines for prayer. However, you should consider the following:

Distraction: If the flag or its symbolism is distracting and hinders your concentration during Salah, it's recommended to move it to a less prominent location or pray in an area where it's not visible.

Respect for the Flag: If the flag represents something that contradicts Islamic beliefs or values, it might be better to move it or pray in a different spot. Islam encourages respect for symbols and objects, and avoiding any potential conflicts with your faith is crucial.

While Islam doesn't explicitly address the issue of praying near a flag, it emphasizes the importance of a distraction-free and clean prayer environment. Your primary concern should be maintaining the focus and reverence required during Salah. If the flag doesn't pose a distraction and doesn't conflict with your faith, praying beside it may be acceptable. However, if it does cause distractions or conflicts, it's advisable to make the necessary adjustments to ensure a suitable prayer atmosphere.

Can I pray beside a Flag?


how to partition the mysql table

Question: I have a badly designed table and to top that number of columns is increasing (~500)because each time a new machine is discovered.(eg: router,adapter windows server etc)..it will store the output of commands which we after discovering that machine which is handled by back-end.

For Example: We discover  a docker running in a machine. We will get the containers and image details....saving those as Blueprints and its properties in the table with appropriate columns;

table contains 1 millions records. We frequently do joins because this particular table is our main table. As to normalize the database now is not feasible, Can anybody give a workaround or any suggestions(like partition or sharding).
Thanxin advance ..Comment if you need more details
Answer: I think you should analyze the scenario from a different perspective, because it looks quite likely that (a) continuing to work with the current structure of the table in question might end up being (b) far less feasible than (c) redesigning it at all the corresponding tiers, i.e.:

the conceptual (modeling and defining [i] the types of things that the table represents and [ii] the respective rules of the business context in which said types of things are involved with [ii] the appropriate precision);
the logical (reflecting the types of things of interest in a database structure with new normalized elements and accurate data types, and setting up the proper constraints so that the data contained complies with the pertinent business rules); and
the physical (establishing a proper indexing strategy based on the exact data manipulation tendencies, installing more powerful hardware, perhaps partitioning and sharding, upgrading the network bandwidth, etc.) levels of abstraction.

Keeping the present table structure (~500 columns!) demands approaching it (manipulation- and administration-wise, etc.) in non-efficient ways, and if you expect that the volume of data will grow considerably then the system will scale very poorly and could become inoperable. It might be much better to employ (1) all the effort devoted to (2) handling this non-optimal situation in (3) a major reorganization.
Of course, there well may be current aspects of the table that can be reused later (e.g., the quite valuable data, which probably needs a clean-up), but I would decidedly consider rearranging—at least partially, at the major hot spots— all the factors mentioned above, instead of putting up workarounds that are in fact palliatives. Better late than never.
Answer: You must bite the bullet and do major revamp of the dataset.
500 columns is untenable, and must be part of the revamp.  Read this about how not to do it, plus suggestions on using JSON as an alternative.  Have a few columns of info that is needed for fetching and filtering; throw most columns into a single JSON column.
Think about what queries you need.  This important when deciding on which columns to keep separate and easily handled by MySQL instead of the application.
A million rows is too small for PARTITIONing or sharding.
You have not described the dataset enough to say whether to have multiple tables (one for containers, one for servers, etc) linked together, and whether there is much opportunity for normalization, etc.
"Vertical partitioning" (two tables with a common PK) may be an option if some subset of the current 'columns' are 'optional'.

how to partition the mysql table


Choosing open source operating system for open source GIS

Question: I'm wanting to get into open source GIS, and it looks like PostGIS on PostgreSQL is a good DBMS to go with, and there are plenty of posts on desktop editors. What I haven't come across (and forgive me if I just didn't find it) is info on what open source operating systems folks are using with open source GIS. Ubuntu, some other form of Linux, etc.
Answer: I use Ubuntu 10.04 for several reasons:

Open source tools command-line tools (e.g. ogr2ogr or pgsql2shp) are much more pleasant to run from almost any linux than from Windows.  Not only is something like gnome-terminal a lot more usable than cmd.exe, but I find that being able to trivially run a few bash commands gives a nice productivity boost for one off tasks for which writing a dedicated python script unworthwhile.
The awesome Ubuntu GIS repository makes it really easy to install and keep updated with open source GIS software.  Anyone installing an open source GIS stack on Windows will appreciate this.

The only major downside I've personally encountered is that ArcGIS doesn't run on Linux.  Thus, for any workflow involving ArcGIS a Windows install is required.
Answer: Most of the major open-source GIS software is compatible in any of the big three (Windows, OS X, Linux). I'd start with trying some of the software out in whatever operating system you're already familiar with, GIS will provide enough challenges without you being flummoxed when navigating your filesystem. Compiling GIS software from source is a challenge on any OS, because of the large number of dependencies (particularly for GDAL) and circular dependencies, so I'd start with binary management.
To get started, I'd recommend the following installations:

Windows: OSGeo4W, which provides a batch install and shell for accessing a significant number of open source GIS packages.
OS X: Kyng Chaos's Frameworks provide many of the common GIS packages.
Linux: apt-get will do the trick. Ubuntu has the advantage of many existing GIS users, making it easier to track down problems.

If you do get deeper into the development world, then I'd say the open source C/C++/Python projects are much easier to manage from Linux, and anything C#/.NET is much easier from Windows. Most FOSS GIS software falls into the former category.
As others have stated, Ubuntu is a great choice once you've decided to dive in, with all the features fmark mentioned. I use it as my primary OS with a Windows VirtualBox instance for the occasional ArcGIS session.
Answer: If you are just looking to get started with open source GIS then you probably don't need to worry about operating system. I can't think of any major programs that won't run on all the major operating systems.
Once you get into advanced work then you might benefit from using a Linux distro but not while starting. So I'd recommend sticking with what you know and concentrating on the GIS aspects.
Obviously if you want to use ESRI products too then you are limited to 32bit windows boxes with only one core.
Answer: While Ubuntu is good for desktop use you will find that there is better support for CentOS(/RHEL) as a server.
From a GIS point of view there is not much difference. RHEL has better manufacturer support so programs for management, backup, drivers (, integration with windows networks) are generally easier to install
Eg. If you buy a Dell or HP server all the management, etc. is packaged for redhat. The most common backup systems all offer packages for redhat. Installing these on other versions of linux is possible but more work. The GIS programs are available in similar packages through Yum on Centos however often you are going to want to install the latest version which will be newer than the one in apt or yum.


SQL Server 2012: Login failed for user. Reason: Failed to open the database configured in the login object

Question: Every so often, my SQL Server 2012 throws the following errors:
Error (likely related to the one below):

Source: spid99
The client was unable to reuse a session with SPID 99, which had been reset for connection pooling. The failure ID is 46. This error may have been caused by an earlier operation failing. Check the error logs for failed operations immediately before this error message.
Error: 18056, Severity: 20, State: 46.

Immediately before the error above (same timestamp):

Source: Logon
Login failed for user 'myUser'. Reason: Failed to open the database 'myDatabase' configured in the login object while revalidating the login on the connection.
Error: 18456, Severity: 14, State: 46.

My ASP.NET 4.5 website (consuming the DB) throws this error at the same time:

System.InvalidOperationException: Internal connection fatal error.

What may be causing these issues and how can I fix them?
Answer: We had the same issue. Several app servers were logging the same error. It turned out to be a bad SFP network port in the Hyper-V hosts frame. As soon as it was disabled all of the errors stopped immediately.


what snake is that in northern italy

Question:

About 75 cm long. Thin tail. Camping site near Grado, Italy, northern Adriatic sea.
It climbed a tree in the rough bark and i followed it to take these photos.
Comment: It might be a better idea to embed the images in your question instead of just putting their links.
Comment: Excellent quality photos and good views of important parts for identification.
Answer: It looks like a whip snake, either a Balkan whip snake or a green whip snake. They are both present in the very north of Italy, close to Slovenia. They both vary in color, but the coloration of this one seems to be more similar to the Balkan whip snake.

See also this discussion.
Comment: Thanks. I first compared it with natrix natrix, but the pattern didn't really match. There are also many small lizards on the camping ground, a common prey of whip snakes. My snake made jerky movements with its head when it was in the low bushes on the ground, I didn't see that in the videos. I'll accept your answer, but I'm open for other suggestions (or confirmations).

what snake is that in northern italy


From Windows 7 + Ubuntu to Crunchbang (First) + Windows 8 (second?)

Question: I'm dual booting a Windows 7 + Ubuntu machine. I went ahead and replaced Ubuntu with Crunchbang, and now want to replace (not in place upgrade) Windows 7 with Windows 8. However, I've always done a dual boot with Windows first. I know that if I now try to install Win8 it will override the boot record. How can I make it so that I can install Win8 without loosing my already customized Crunchbang install?
Comment: Since you already replaced Ubuntu with Crunchbang, you should remove the Ubuntu tag from it.
Comment: great point removing tag
Answer: If (a very important if, so make sure you understand the difference first) you are using an MBR style hard disk, as opposed to the newer GPT style, you can simply back up your MBR (master boot record) before you install windows, then replace it afterward.  To back-up:
dd if=/dev/sda of=mbr.copy bs=512 count=1

"/dev/sda/" should be your actual hard disk (notice, not "sda1" or "sda2", just "sda").  Put that file somewhere safe where you can easily access it again.
Now install windows, which will overwrite the MBR you just backed up.  Afterward, boot a linux live CD or something (since you won't be able to boot the crunchbang partition) and beware since you are now using some other medium, sda might not be the same drive it was before.  If it isn't replace "sda" with the correct dev node below, and back up the new windows mbr, just in case:
dd if=/dev/sda of=ms.mbr.copy bs=512 count=1

Keep that somewhere safe where you won't forget what happened to it. Now replace the MBR with the other copy you made before:
dd if=mbr.copy of=/dev/sda bs=512 count=1

You should be able to reboot now and get the grub menu.  Hopefully, the new windows will boot with the same menu entry as the old windows -- if not you have to sort that out.
You can use the ms.mbr.copy the same way in the future if you have a need for that.
There might be a similar way to do this for GPT, but since I haven't tried, I can't say.  An easy way to tell whether your disk is GPT or MBR from linux would be to try gdisk -l /dev/sda.  If you don't have a GPT disk, you'll see a big warning, "Found invalid GPT and valid MBR; Converting MBR to GPT" (don't worry, it doesn't actually do that when you just run -l).
Comment: 1. How do I find out what kind of hard disk Im using?
2. How can I check if the new windows will boot with the same menu entry as the old?
Comment: 1. Sorry, it's more properly "GPT" (for GUID Partition Table), and it was developed as part of UEFI (which is sort of a BIOS style).  Having a UEFI "BIOS" (really it's not a BIOS, it's a UEFI) doesn't mean you have GPT but it may be required.  I added a sentence in the last paragraph about how to tell GPT from MBR.  Windows will probably say something somewhere too: http://www.tomshardware.com/forum/268934-32-disk
Comment: 2.  As for the dual boot issue, just try it.  If it is on the same partition, I say it will probably work; one issue (probably, the only issue) will be if grub is using the UUID of the partition, which changes when you reformat it.  You can get the UUID with `blkid /dev/sda1` (or sda2, if that's where windows is), then you just change that in `/boot/grub2/grub.cfg`.
Comment: @goldilocks: cgdisk and gdisk allow you to back up a GPT partition table. Not sure if it will still work, though.


Preloading 20MB+ of images. Is it worth it to attempt this?

Question: I'm developing a photography portfolio website. I want to know what would the best practice be for downloading images from a database. As of right now the entire gallery is roughly 20MB. The gallery is still in development, I intended on just having an "loading" graphic run between photos. But the client seems to prefer image preloading. Is it practical to have the page preload 20MB+ of photos, and if so, what is the best way to do so? Or would it be best to go with the loading screen?
Comment: "Or would it be best to go with the loading screen?"?  What does this mean?
Comment: If your client wants preload I would say that a loading screen would be a good idea rather than just letting the browser hang as it preloads in the background.
Comment: @Kragen gives a very good reason why you shouldn't do this, although if your client insists, and you can't change their mind, then you should place a disclaimer notice, perhaps on a splash page, informing all visitors that accessing the site will cost them 20MB credit. I used to use a mobile connection myself and actively avoided pages and sites which had autoplaying video, music and buffered image caches.
Answer: Why not "thumbnailing" images via some server side script, preload thumbnails & display full image on thumbnail click (using some kind of lightbox js)
This would reduce a lot preloading time while keeping full porfolio preview.
Answer: 20MB to fetch in one go is too much, it will result in a slow and annoying user experience. You should probably ajax-load each image in turn.
Incidently, how big are your images? An 800 x 600 jpeg should be around 50k at 90 - 95% quality. So 20 MB would be 400 images. This seems like a lot for one page. I'm guessing your image sizes are large - consider reducing them. If you want to have hi-res, non-compressed versions available, have these individually linked.
Edit: Just for reference, what I would consider a very large page (the html doc + all css, js and image assets) would be ~ 1MB. An "average" sized page is probably ~ 100k.
Comment: This would explain some things. The images he sent me were 800x600, but 200-700kb. I compressed them and that brought the size down a lot.
Answer: I think the better way is to preload the next couple of photos while you are viewing the current one
Answer: Yeah, definitely don't do this.  Rememebr that some users will be connecting with mobile connections and some of them paying by the megabyte - if you do this then you've just used up 20 MB of their allowance with images that they may never see.
Answer: I don't think either solution is practical - I would suggest you scale down your images.
Answer: 20MB is probably too much unless it is a specialized application where you are confident that 1) users will wait and 2) that they will view the majority of those images. Otherwise, you are wasting bandwidth.
I would look at a strategy where your images are cached in server memory to avoid database traffic combined with client-side pre-caching of a few images where you can add it. For example, if the user is on image "A", load "B" and "C" as well.


pinax setup_project command doesnt work

Question: when i try to create new project in pinax, this is what i get
(mysite-env) (path)>pinax-admin setup_project mysite2
Unknown command: 'setup_project'
Type pinax-admin-script.py help for usage.
pinax-admin clone_project is working well. help please
Answer: You could start cloning an existing sample project.
This would install the "skeleton" for a pinax project. Then you can add or remove apps.
<code>>> pinax-admin clone_project basic_project mysite
</code>
For a lists of sample projects
<code>>> pinax-admin clone_project -l
</code>

pinax setup_project command doesnt work


Not able to change flash settings

Question: My Gnome crashes constantly when I open web pages containing flash so I tried to turn off the hardware acceleration. I opened the Adobe flash player settings panel but found that the buttons are not clickable.
I can still switch between display/privacy/storage... panels using Tab and Enter key. But for others like the "Enable hardware acceleration" checkbox this won't work.
Anyone knows how to solve it?
Comment: The problem appears in both Chromium and Firefox. I installed adobe flash player from Ubuntu software center. Reinstalling doesn't work.
Comment: I would reccomend to reinstall flash. What browser do You use, what flash? How did You install it?
Comment: Please deliver us the version of Ubuntu You are using. Maybe you should try to install flash not from USC but by downloading it from websiite (there is a special version for Ubuntu)
Answer: The easiest way to disable hardware acceleration in flash is to do it in the flash player window from the right click > settings & un-check the box for hardware acceleration.
In many cases though the box can't be clicked. If that's the case then  you must not have scrollbars present so use F11 to fullscreen the window, then you'll be able to click in  the box. After doing so press F11 again to return to normal window. (happens mainly when using compiz. On a 32 bit player going fullscreen works here, on a 64 bit player it currently  doesn't
I don't see a "Adobe flash player settings panel" but if it's available with the option to disable hw accelerating then try to full screen it if the box isn't clickable
An alternate method would be to access the player settings in a non compiz session which is the surest way to do
Answer: I was able to make it work. Ahuh!
Use Tab button until it highlights the whole Flash Player settings box, then press Tab button again until it highlights the "question mark" button on the right upper part of the box. Press Space bar or Enter button repeatedly until it opens another tab on your browser. Now go back from the previous page where the Flash Player settings is, press Tab button again until it highlights the "Allow button" or "Deny button" depending on what will you do. Press Space bar or Enter button and voila! There you go!
Hope it helps. Have a pleasant evening everyone! :)
Answer: You can change flash privacy settings for specific websites online.
The settings are stored in your browser and then you can do things like use Youtube and your own webcam to create and upload a video.
Answer: Have you tried gnash?  It's available via software centre, you could try uninstalling the adobe flash and using gnash instead...
Answer: I had the same problem and logging under Unity 2D allowed me to click and change the Flash settings. Logging again under Unity 3D revealed that the settings were conserved between the two sessions.
Answer: Recently I updated to Flash Player 22.214.171.124 and ran into a problem where I did not have audio and video.  Removed 22.214.171.124 and installed Flash Player 188.8.131.52.  No more problems!!!  Please refer to these instructions on Mozilla Support and Adobe's Archived Flash Player versions.
Answer: You have to download the .deb from Adobe Flash web. Later you have execute it in Ubuntu Software Center and enable Adobe Flash KDE. When you enable adobe flash KDE you can change the privacy and web exception in Flash Control Panel.

System → Preferences → Adobe Flash

Not able to change flash settings


Open Comment Reply Form On Button Click

Question: I have a blog that has a reply form for each comment on the blog. I am trying to create a "Reply" button that would show the form once its clicked. Right now, if I click any "Reply" button it will only apply the hide style to the first button and the block style to the first div.
HTML

  <button id="replybutton" onclick="replybutton()">Click Me</button>

    <form>
      ...
    </form>

HTML
function replybutton() {
  document.getElementById("replyform").style.display = "block";
  document.getElementById("replybutton").style.display = "none";
enter code here

Comment: I think you have more than 1 item with the same identifier. Try using unique Ids for each button.
Answer: The id are supposed to be unique. So each form should have a unique id. You can use a common class to show/hide them.
When you click a button you should pass its reference to your onClick function like this onclick="replybutton(this) and modify your onClick function to target the button function replybutton(btn). If you want to show/hide your form you can use the nextElementSibling
See the jsFiddle
https://jsfiddle.net/th4dz1q0/2/

Open Comment Reply Form On Button Click


Do the concepts of typographic scale and vertical rhythm apply equally to print media and web apps?

Question: I have been learning about these two fundamental concepts and I see how beneficial they are for print media (including 'digital print' like blogs and webzines.) do these concepts apply equally to dynamic or data-driven web applications, and should designers strive to regularly apply them in such projects as well?
Answer: Just because the medium changes doesn't mean visual balance no longer applies. Because web apps are in a browser and browser sizes vary depending on the user, it is a bit different when comparing it to print media, where the designer knows explicitly the dimensions of the final product.
Design is not an exact science, but setting appropriate css rules with a proper hierarchy of font weight, sizes, and margins will help with scale and vertical rhythm - so yes, they are equally important, but they are different in application because web apps can have much more content.
Comment: "where the designer knows explicitly the dimensions of the final product." <-- But he also needs to be aware of how this product will be perceived. An ingredients table on a chocolate bar package a handsize away from you or a city ad of several m² 150 m away from you


Can't install Ubuntu 14.04 shows black screen. GTX 750 Ti

Question: I'm having trouble installing Ubuntu 14.04 from flash drive. I can see the options for trying, installing and checking disk for defects but if choose any of them it's just a black screen. I can hear a jingle when I try "Try Ubuntu without installing" and "Install Ubuntu" options but it's still a black screen.
I have Intel i5 4570, GTX 750 Ti with 4GB of RAM.
I do have Ubuntu 14.04 installed right now but I want to totally reinstall it.
Answer: This is simple! Took me a while to work it out, but I had the same issue, and it turned out it was using the onboard Intel GPU!
Even if your BIOS has your Nvidia card as default, for some reason, Ububtu still uses the onboard card, so it is actually booting, you just cant see it!
The solution: Go into your BIOS and disable your onboard video. When you reboot, leave the black screen for a few minutes, and the mouse should appear.
This may not working in all situations, but its an easy thing to try first!
Comment: The solution to disable the onboard video card in BIOS setup worked and it was able to boot for GTX 980 with Ubuntu 14.04. Now it takes the NVIDIA by default and loads properly.
Answer: Wait longer.
I have an Intel i3-3225, 8 GB RAM, GTX 750 Ti. I booted 14.04 off a 2GB usb stick and chose "Try Ubuntu without installing". I got the black screen and thought I had replicated your error, but after waiting a while the mouse showed up, then waiting a little longer the desktop displayed. So if you haven't yet, try waiting several minutes.
If waiting longer doesn't work, shout down your PC and unplug your graphics card from the motherboard. Your processor model has Intel HD graphics which has better supported drivers than that brand-spankin-new graphics card does. Do your fresh install of Ubuntu on the Intel HD Graphics. When that's done, shut it down and plug your card pack in.
Comment: Thanks that worked perfectly. I had to use Intel HD Graphics and then manually install Nvidia's GPU drivers.
Answer: During boot (bios or black screen and white text appears on UEFI.)  For MultiSystem LiveUSB, at your chosen boot option in the menu.

Press e and add nomodeset before quite splash words.
Press F10 and it will continue to boot in non 3d mode
Install ubuntu as usual
On first boot, use again nomodeset as described in first statement

then;
sudo apt-add-repository ppa:xorg-edgers/ppa
sudo apt-get update & upgrade
sudo apt-get install nvidia-337 #( don't install that before command above)

then;
sudo gedit /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

and change it to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"

save & close
then;
sudo update-grub

restart.
Answer: Simply start the Ubuntu installation using the Intel IGP (Integrated Graphics Processor) instead (make sure to modify this option in the UEFI Bios). When you finish the installation, download the linux drivers for your graphics card, install them to be able to use your graphics card and you'll have it done.
Answer: I had this issue on two machines, both running Debian (so not exactly ubuntu but close). I tried various kernel parameters like nofb and nomodeset but without success.
On one of the machines MicWit's suggestion of disabling the onboard graphics in the bios fixed the blank screen issue but left X unusable. The screen was both blurry and blocky as if the image had been downscaled and then re-upscaled, text was unreadable.
On the other machine MicWit's soloution made no difference but what did work was renaming /lib/modules/<kernel version>/kernel/drivers/gpu , this prevented whatever the borked driver was from loading and fixed the blank screen issue. X11 was somewhat usable after doing this but was stuck at 1024x768.
In both cases after dealing with the blank screen issue I had to install the Nvidia binary driver to make X11 work properly.


Why does this component on my Arduino UNO heat up?

Question:
Every time that I plug my Arduino into the computer, this chip immediately gets burning hot, way too hot to touch, this wasn't something that i noticed happened after a particular event, I just noticed it one day. On the chip it reads "52 TI MSP" I googled this but I couldn't find a datasheet. So what does this chip do? And what could have caused it to break and heat up? I have noticed that the board still works, but is it safe for me to keep using it (for the computer and the rest of the components on the board... and myself)?
Comment: Arduino schematics and layouts are freely available, shouldn't be too hard to figure out. Looks like one half of a dual opamp.
Comment: Found the schematic of the UNO rev 3 on line: www.arduino.cc/en/uploads/Main/Arduino_Uno_Rev3-schematic.pdf The component is a dual op-amp LMV358IDGKR.  I assume you use only the USB cable.  I don't see an immediate cause.
Comment: @oldfart What could be the reason for it heating up?
Comment: As I said ** I don't see an immediate cause.** There could be a dozen causes and for that you need to probe around the boards and have a thorough knowledge of electronics. Debugging is as much an art as it is science.
Comment: One thing to check would be if any pins on that chip are shorted to their neighbour due to soldering problems.
Comment: @Brian Drummond But this is a board that I have been successfully using for over two years... why did this problem pop up for no apparent reason?
Answer: According to the Uno rev 3 schematic that part is an LMV358 dual op-amp, it drives the mosfet power selection switch and also drives the "L" LED. https://upload.wikimedia.org/wikipedia/commons/7/7d/Arduino_Uno_Upload.png
It you continue using the board there is a chance the chip will eventually burn even further and potentially cause other problems, in an extreme case the chip might blow its top throwing tiny shrapnel bits around.
The op-amp section that drives the LED has a series 1k resistor, so unless there is a short ahead of the resistor that shouldn't be the problem, but does the LED still flash at times? The other op-amp section drives the gate of a mosfet that selects the main system power source (usb or external).
Mosfets, especially discrete parts, can be very susceptible to damaged from a static zap.  During winter months low indoor humidity can greatly increase the potential for static problems.  Since one pin of the mosfet connects directly to the usb 5v there is a chance that just the act of plugging and unplugging the usb might have  caused a static zap to the Uno board.
If the mosfet's gate became shorted to either the drain or source pin that could easily cause heating of the op-amp chip, (the op-amp's output would then be shorted to one of the power supply lines).  Check if the mosfet is also getting hot.  The mosfet is the small 3 pin device just to the right of the fuse (which is just below the usb connector in the Uno picture you uploaded).
If you suspect the mosfet is defective you could try removing and/or replacing it, (the mosfet type is listed as an FDN340P.)  But if you do take that repair route keep in mind two things, without the mosfet the Uno will only operate when power is supplied from the DC jack.  Another issue is that in removing the mosfet there is a chance that just in that process you could damage the part, so if you really want to remove/replace the mosfet do use static protection, (a static wrist strap and even connect the Uno ground to the same ground as the strap). But before doing any component work do check for other obvious problems like shorts or bent pins, also be sure your not shorting something out with other I/O lines too.
If you do decide to try a repair it may be best to just go ahead and replace both the mosfet and op-amp.
Comment: Yes, the L led sometimes flashes really fast for a few seconds and turns off, The small chip next to the op-amp seems to be heating up as well, is that connected to the op-amp as well? It might just be from the heat from the op-amp.
Comment: And no, the MOSFET doesn't heat up.
Comment: The chips to the left and just below the op-amp are voltage regulators. If there is excess current drain (like due to a shorted mosfet), one or both of those parts might heat up. Most modern regulators will have a limiting function so it would be less likely one of theses would burn out.
Comment: The mosfet could still be defective even if it is not getting hot, it would depend on the actual type of damage it sustained.


Why would this h-bridge driver circuit include capacitor across MOSFET's?

Question: In the typical connection diagram for the IRS2007 Half-Bridge MOSFET driver taken from here and shown below, what is the function of the capacitor in parallel with the two MOSFET's (is it just to stabilise the power rails) and if critical how would an appropriate size be calculated?
Comment: Decoupling capacitor.
Comment: It depends on the power feed and the load.
Comment: I have studied more than 5 H-bridges (l293x, l298x, DRV3xxx, TB6xx, BTS/BTN79xx, all for 40V or lower), but I have never seen any such capacitor inside the chip.  Is ti because the high 200VDC power supply needs an internal bypass cap?
Comment: I am reading App Note 978:
https://www.infineon.com/dgdl/Infineon-HV_Floating_MOS_Gate_Drivers-ApplicationNotes-v01_00-EN.pdf?fileId=5546d4626c1f3dc3016c47de609d140a. Section 6 6. says the following: "To eliminate the effects of the inductance of the wiring between the power supply and the test circuit, a 100 uF/250 V electrolytic capacitor was connected between Q1D and Q2S terminals, as shown in Figures 6 and 7. ***This virtually eliminates any stray inductance in the dc path.***. So I think the "by pass" cap Cf 250V 100uF is to ***eliminate stray inductance, not simply bypassing***.
Answer: I see you've already accepted an answer but that answer misses an important point about the power feed and the load. For instance, if the power feed is from a voltage regulator then energy transferred back to the power rails when switching an inductive load or a load that can produce energy (a motor for instance), will try and raise the "regulated" supply voltage. This happens quite easily with a series voltage regulator because there is no mechanism inside it to "shunt" away excess energy.
This means that a capacitor (of decent value) is required to be across the voltage rails to "soak" up the excess energy being returned by the load through the MOSFET parasitic diodes. This isn't needed with resistive loads but inductive loads (or motors that can generate when being mechanically rotated) will (or can) force the supply voltage higher than the supposed regulated value.
Path of current flow when a motor is connected as a load and allowed to free-wheel: -

You should be able to see that without a capacitor, there is nothing to prevent the voltage rails rising to an unacceptable level.
Answer: It seems to be bypass capacitor to stabilise the power rails
This application note gives the same schematic

the appropriate size will depend on the power rails, the value depends on the noise frequency


How big is Gingerbread 2.3.5 on internal 8GB memory?

Question: How much space does the Gingerbread version 2.3.5 occupy on the internal memory drive ?
I've bought the Samsung Galaxy Player 5.0 and it promised  8GB, when I checked the size it said 5GB and only 4.85GB are actually available. What's going on ?
Answer: This seems pretty normal. The 8GB iPod Touch is similar - iOS takes a significant portion of its storage.
The device itself has 8GB of storage, but any OS takes space - particularly Samsung's flavor of Android, which has a lot of stuff added (Which, unfortunately, they don't want you to be able to remove).
Comment: Thank you for your answer and taking the time, dotVezz !! I appreciate it. I think I can live with the fact that you explained, just for being able to use my Samasung Galaxy which is a fantastic little device, helping me avoid cell phone bills, and so many other things.  Thanks again.
Comment: @Christian If you're happy with the answer, please feel free to upvote it and mark it as accepted =)
Comment: Do note too, that your standard device formatting stuff also applies (i.e. how you don't really get 1tb of hard drive space from a 1tb hard drive) Formatting eats up a chunk of it as well.  Fortunately the Galaxy Player has a microSD card slot, if i correctly recall, so that can be used to extend the capacity of the device, should you need more space -- microSD cards are also relatively cheap too, provided you're not looking for a ton of space.


Cleaning Activities Data

Question: I'm trying to lower the storage usage.
I know that the archived Tasks is taking a lot of my storage.
I tried to do it several ways but still no success.
1. I used the Data Loader "Export All'. My query has some filters. However, even if I limit the result to 1000, I got error message the "query run too long"
2. I tried to write a batch apex to do this. I don't know how can I query the archived records in batch apex. Can I pass the query with a "All ROWs" signature to the class?
3. I am sure there's some tools can help me with this. Are there any mass delete apps also delete archived records?
Answer: Use the Dataloader with the Export All option, and include the isarchived=true filter with your other filters.
Answer: Honestly, the best way that I have found to do this is through Setup. Go to Setup, Data Management, and then Mass Delete Records. From there, click on "Mass Delete Activities".
If you only want to clear out Tasks, make sure to set that as one of your filters.
Yes, this is kind of tedious, but it works!
Comment: Thank you! That interface only allows me to work on a few hundreds of records at a time. I have about 200,000 records to be removed.
Comment: Yes, the 250 limit is obnoxious, but it does move fairly quickly. Keep it in a separate window on your second monitor & you can blast through them faster than you think.

Just my 2 cents.

Cleaning Activities Data


Clickjacking: can't browsers just forbid/reject placing transparent elements over frames?

Question: Why not? Seems like this is only used for clickjacking, the solution should be simple enough.
Comment: just because you can't think of a usecase except clickjacking does not mean that there are none.
Comment: Transparent elements are used a lot - generally to provide user functionality and smooth visual transitions.
Answer: Banning opacity on elements containing an iframe would have negative impact of user interfaces (eg no nice fade effects when iframes are in play), but would not block clickjacking attacks.
Even if transparent iframes were impossible, you could still achieve all the same attacks by using a 1x1 pixel iframe that followed the pointer. Positioning inside that pixel can be achieved by scrolling a doubly-nested iframe. The potential one pixel difference underneath the pointer at rest would almost certainly be undetectable to the user.
So, yes, a browser could block it and temporarily be protected against a common form of attack. But as soon as a significant number of users have browsers that do that, the attacker will just change implementation technique. This is an example of a 'fix' that only works by making someone else the low-hanging-fruit; once everyone starts doing it, it is no solution at all. Consequently it makes sense to implement for a browser extension that not many people use, but no sense for a popular browser.
Answer: Some plugins will do this, or warn you of when it is occurring.  Check out NoScript.
Answer: FYI there are other ways to do clickjacking without iframe transparency, so it wouldn't help anyway.

putting a non-transparent element on top of an iframe and set some CSS to make it be transparent only to mouse events
change cursor style to something not very visible and putting a fake mouse that will be shown 200px to the left of the real one

Only way to prevent clickjacking is to alter the gui (random positioning of BUY button?) or create confirmation sequences for critical actions (eg. force people to use keyboard)
Comment: Is there even one legitimate use for custom cursor styles?
Comment: Well, yes... People want to indicate different interactions with cursors like `pointer` or `help`. The cursor I had in mind is `crosshair` - totally invisible for windows users without perfect eyesight (at least when I used windows last time, it mihgt have changed)
Answer: Even if browsers disallow overlaying elements (over iframes) and figured out how to deal (when deny) with opacity. There are still clickjacking techniques which can workaround these rules, for example, iframe resized to 1×1 pixel size and then attacker adds as many such iframes as he need to draw custom graphics by using those iframes.


Can I run water lines through the attic?

Question: I recently had a Slab leak in my home in Indianapolis,IN. This is the 4th Slab leak since I've owned the home. I decided it was time to reroute all the Water lines. I thought this was best so I wouldn't have to deal with anymore slab issues. We had pex lines run through our attic space to the bathrooms and laundry area.
Pex had to be ran under the concrete from the utility closet to the Kitchen. All the lines are tied to a Manifold.
After reading some info on this site, I am alarmed that we may have frozen lines in the cold temp.
The pex was run about 3 maybe 4 feet above the blown in insulation. The lines were fastened to the rafters. Black insulation was used to wrap the lines. I've been told that this is out of code in Indiana and that the lines need to be rerun inside the home. Just below celing. Then celing would have to be framed and new drywall attached.
Help! Anyone that can provide any information about what we should do, would be appreciated.
Comment: Well, bottom line is that the lines do need to be routed so that they are in warm space. Who was it that decided to mount the lines above the attic insulation? (A contractor from southern California where attic water line installs are common?) Maybe the proper fix for the under the slab routing of the water lines was to install 4" diameter PVC piping under/through the slab that has all gradual turn corners. Through this can be pulled the PEX water lines. If ever a leak you can pull new lines through the PVC without digging up slab once again.
Comment: My money says the lines will freeze. PEX is pretty resilient to splitting when water freezes inside it, however the fittings are not. This is a leak waiting to happen. Also, I can't imagine a licensed/bonded plumber did the work; that could impact insurance coverage if a leak results in damage.
Comment: Possible duplicate: [Will a PEX run freeze if it's in the attic above a foyer?](http://diy.stackexchange.com/q/10784/2196)
Comment: @user18116 I think you still run a high risk of your pipes freezing. If there are no tee's or joints in the cold area, it seems less likely to me that you would have a leak.
Comment: There are no joints in THE PEX in attic.
Comment: There are no joints in THE PEX in attic. The fittings are all inside the home. So If the lines freeze in the attic that would mean the Brass Fittings, which are shark bites, could leak? It was a home remodeler that did the work. He said he had to reroute his home and has had no problems. But since my home is In Indiana, and it can get very cold in the winter, I am concerned. I just paid $2300.00 for this contractor to reroute lines. I had a Licensed Plumber come in to look at the recent work. Estimate $2400 to reroute inside. Ugh!
Comment: What length of waterline do you have exposed in this manner? If it's short enough, then a heating cable could be temporary fix.
Comment: You should mention the sharkbites in the text of your question, as those should be converted to better fittings.
Answer: The simple solution is to dig up the insulation, run the pipes along the top of the ceiling drywall (ie, just above the ceiling, rather than just below it), and put the insulation back on top of them, which puts them on the warm side of the insulation, "inside the home (thermally speaking)." Also to be a lot more careful when hiring "plumbers."
Otherwise, framing in a pipe chase below the ceiling would work, and might actually be easier in some cases (where crossing rather than running along ceiling joists.)
Comment: I agree pex is easy to move arround pull it down a bury in the insulation. Since you don't have any fittings in the attic I doubt you will have any problems with the pex buried in insulation.+
Comment: Time to install that crown molding that I've always wanted.
Answer: Well I am a master plumber in Indiana for 33 years. If you think putting water lines in an attic is a good idea, then enjoy that massive insurance claim. It is against code. To make it legal you would have to stack the insulation damn near to the roof. You can not close all your ventilation to your arrive. That causes condensation which causes mold. Indiana winters can be harsh. Is it worth the risk?  The only thing that is more damaging to a house , other than fire , is water. Keep that in mind and good luck
Answer: I had to replumb my house to get rid of the crappy poly-B piping that has been vexing me with leaks for the past two decades.  Rather than rip out my interior to put new PEX pipes in, I ran two 3/4 inch PEX risers up inside my chimney chase from the basement all the way to the attic.  From there, I located the top wall plates and dropped half-inch lines off the 3/4 down into the walls for the bathrooms. I made small cuts in the back of the vanity cabinets and brought the new pipes into view.  For bathtubs, I was able to cut small access holes in closet walls opposite the tubs.  I fit nice little flush-mount panels back in to fill the holes.
My attic had 12 inches of blown rockwool insulation.  I dug little trenches down to the ceiling drywall so I could lay the pipes right in the drywall.  I made little U-channel box covers out of styrofoam to cover the pipes, and then filled the rockwool on top.  This created a little cavity where heat from the house can dissipate (through the drywall) so the pipes stay essentially at house temperature.  Also, for added insurance, I laid a heat-tracer tape (made for that purpose) alongside the pipes.  It is thermostatically controlled and will come on as the temp drops below 40F.  Given the location of the pipes (right on the drywall) and the insulating method I used, I doubt the tape will ever come on.  I also put a remote reading thermometer up there at a point right on the pipes so I can monitor the temperature at that point remotely.  Knowing I'd have to do this plumbing retrofit, I put the thermometer up there last fall, and it remained within a degree of room temperature all winter, even in February when it exceeded -30 for some time.
If done carefully, you can avoid any potential for freezing, but proper location and insulation is the key.  The heat-tracer tape is 80 feet long, cost $120, and gives off about 3 watts per foot.  It just gets pleasantly warm, but not hot.
Answer: I don't see where running your line under the ceiling insulation yes you should try to keep the fitting in the walls but also heat rises and if you insulate the lines i really don't see it freezes. Also if you feel its going the be real cold at times you can alway let the water run at trickle to stop from freezing.
Comment: It gets really cold in that location I have seen -20 and below so putting the apex under the insulation would be a good idea.
Answer: This advice is coming from a Master Electrical Engineer who graduated from Penn State in 2012, so  take the advice with a grain of salt.
First off, these days water lines going through Attic are standard practice especially if you have a slab concrete foundation.  The makes the price affordable and allows for minimum tear down during the plumbing repair.  While this will may make you work a little more to properly insulate the water lines, it will save you tons of money upfront.
Installation technique for PEX lines in the Attic varies according to geographic location.  For example, Montana that has those average winter cold nights of -7°C (Wikipedia) will need some extra insulation on PEX lines to account for those windy nights where the chill factor and any non-desired holes allowing airflow to drop the temperature in the Attic further.   Remember that Attic temperatures need ventilation holes be it gable grill, soffit ports, turbines, or any Attic fan in order to match Attic temperature to outside temperature and also to control humidity and condensation in the Attic.
Having analyzed that Attic temperatures should be 10 to 15 degrees  warmer with adequate ventilation, it is my opinion that sufficient insulation around PEX tubing should keep the lines from freezing.  Do use the sticky tape to create a hermetic enclosure for the new PEX water lines.  If they freeze for any reason, check your Attic ventilation and seal ventilation holes during the winter to warm the Attic.  You can also consider using an Attic heater if one exists in order to keep the temperature just above 0°C.
Comment: Daniel, you won't graduate for 84 more years?
Answer: In Indianapolis you're under an amended version of the 2006 International Plumbing Code. From the list of amendments:

Delete the text of Section 305.6.1 and insert to read as follows: Waterlines. Waterlines shall not be installed outside of a building, in attics or crawlspaces, or in any other place subjected to freezing temperatures, unless adequate provision is made to protect such waterlines from freezing by insulation, ambient heat, or alternate heat source. No waterlines shall be concealed in outside walls, above grade.

There's actually a mistake in this amendment, where it should be referencing 305.6, not 305.6.1. Regardless, your waterlines don't need to be below the ceiling. They just need "adequate provision" to protect from freezing, and they can't be located in exterior walls. Google puts Indiana's frost line between 24" and 36", where the length of waterline involved in your system needs to be itself heated (depending on the length, this could be a cheap solution until you can afford a more permanent solution) or it needs to be located within your home's thermal envelope.
For locating inside your home's thermal envelope, the waterline should be run beside ceiling joists and through ceiling joists. For lines running parallel to the joists, attach the waterline to the ceiling joists every 2'-8" or less. For lines running perpendicular to the ceiling joists, bore holes in the ceiling joists where the hole edge doesn't come within 1-1/2" of the ceiling's drywall. Maybe you could get away with strapping the water lines to the tops of ceiling joists, but I would be afraid of an inspector rejecting this as a "location exposed to damage." I would reject it if I was an inspector.
The 1-1/2" comes from the 2006 IPC's 305.8:

In concealed locations where piping, other than cast-iron or galvanized steel, is installed through holes or notches in studs, joists, rafters or similar members less than 1.5 inches (38 mm) from the nearest edge of the member, the pipe shall be protected by shield plates. Protective shield plates shall be a minimum of 0.062-inch-thick (1.6 mm) steel, shall cover the area of the pipe where the member is notched or bored, and shall extend a minimum of 2 inches (51 mm) above sole plates and below top plates.

The 2'-8" spacing along ceiling joists comes from Table 308.5 which specifies a maximum hanger spacing of 2.67 feet for horizontal PEX runs and 10 feet for vertical PEX runs.
Any pipe laying on the face of your ceiling's drywall is not conformant.


Piecewise convexity and global convexity

Question: Let $f:\mathbb{R}\rightarrow\mathbb{R}$ be continuous on $\left[0,1\right]$.
Consider $z\in\left(0,1\right)$ and suppose that $f$ is differentiable
and convex on $\left[0,z\right]$ and $\left[z,1\right]$. If $f'$
(i.e., $\frac{df}{dx}$) is continuous at $z$, then $f$ is convex
on $\left[0,1\right]$. - Is this proposition true? While I could not create a counter-example, I am finding it difficult to generate a clean proof as well.
Comment: OK, I got your answers, and thank all of you for that. However, I would like to add something more to this question. To what extent, can I relax continuity of $f'$, and still have global convexity? Following your lines of proof, it seems to me that as long as the left-side derivative ($f'_{-}$) at $z$, which is well defined, is less than the right-side derivative ($f'_{+}$) at $z$, which is well defined as well, global convexity prevails. I do not need continuity of $f'$ precisely - Is this correct?
Answer: A differentiable function is convex in an interval $I$ if and only if $f'$ is increasing in $I$. Now we have that
$$f'(x)\leq f'(z)\leq f'(y)$$
for any $0\leq x<z<y\leq 1$. Can you take it from here and show that the proposition is true?
Answer: A differentiable function $f$ is convex on an interval $(a,b)$ if and only if its derivative $f'$ is increasing.
Therefore, your assumptions imply that $f'$ is increasing on $(0,z)$ and on $(z,1)$. Now your assumption that $f'$ is continuous immediately gives you that $f'$ is increasing on $(0,1)$ and therefore convex.
Comment: Yes, you are right it generalizes in the way you suggest it. But note that this does not follow from the proof I gave because the criterion I used needs that $f$ is differentiable in the whole interval. If you weaken this assumption you will have to proof it in a different way. I think it will boil down to using the definition of convexity and show it explicitly like one would show the theorem I used in my answer.
Comment: Thanks for your answer. If I relax continuity of $f'$ at $z$, and just assume that the left-side derivative of $f$ at $z$ is less than the right-side derivative of $f$ at $z$, global convexity will still hold - is it right? In fact, I was wondering that is an "if and only if" condition to maintain global convexity.
Answer: Yes it's true. $f$ is convex iff $f'$ is monotonically non-decreasing, but it works on $[0, z)$ and $(z, 1]$. But $f'$ is continuous at $z$ so it can't be less than 0 otherwise there would be a neighborhood where it is negative and thus not convex.


relocate key numbering list on layout

Question: I am creating a map of local authorities in Hampshire, UK and due to size, key numbering is the best option to clearly label.
The list, however, is not in an ideal location. Is there a way to relocate the list to another area of the map layout?
Answer: You can convert the key numbering list to annotation and position it that way. However, if you need to change the numbers or order in the future it could become a bit of a pain. There's some other really good answers on this GIS SE that involve sample scripts and work arounds for a similar scenario you have.

relocate key numbering list on layout


What is a reducible flow graph?

Question: What is a reducible flow graph?   sorry if this is a stupid question but I'm having trouble finding an answer.
Also multiple equivalent definitions and some motivation would be nice too.
Comment: Googling "reducible flow graph" seems to give a lot of relevant hits.
Comment: https://en.wikipedia.org/wiki/Interval_(graph_theory)
Comment: I've found weird definitions like
 A flowgraph is reducible when it does not have a strongly connected subgraph with two (or more) entries
which I believe should be equivalent to being acyclic???
Or a flowgraph is reducible if Every back edge has its source dominated by its target, for all DFS trees
I also don't understand this definition wouldn't every edge have it's source dominated by it's target by definition?
Answer: This blog post summarises the situation well my opinion, but let me go through some of your concerns:
Reducible is NOT equivalent to acyclic: consider a path $x\rightarrow y\rightarrow z\rightarrow w$ with a loop from $z$ to $y$. Then there is an SCC $\{y,z\}$ so it is not acyclic. But it is reducible because the SCC $\{y,z\}$ has a single entry point y. Notice how this corresponds to a program with a while/for loop. On the other hand, if you consider a path $x\rightarrow y\rightarrow z\rightarrow w$ with again a loop $z\rightarrow y$ but also a forward jump $x\rightarrow z$. Not this is not reducible anymore because the SCC $\{y,z\}$ has two entry points: $y$ can be entered from $x$, but $z$ can also be entered from $x$. This intuitively corresponds to a program like that:
<code>x: if <some condition> goto z
y: do { <instruction>
z: }while(<cond condition}
w: end
</code>
Notice how there is no way to jump to $z$ without a goto, this is the point of reducibility and it corresponds to well-structured code without goto.
Concerning the back edges, if you take the counter-example for above, notice that there are two different ways to explore this tree in a DFS:

from $x$, explore $z$ then $y$ and $w$: in this case the edge $z\rightarrow y$ is part of the spanning tree built by the DFS. But $z$ does not dominate $y$ because the path $x\rightarrow y$ does not go through $z$.
from $x$, explore $y$ then $z$ then $w$: in this case the edge $y\rightarrow z$ is part of the spanning tree built by the DFS. But $y$ does not dominate $z$ because the path $x\rightarrow z$ does not go through $y$.

Maybe the source of your confusion is that domination is related to the initial vertex $x$, and not to the DFS. Recall that a vertex $y$ dominates a vertex $z$ if every path from the initial vertex to $z$ goes through $y$.
Comment: I'm confused because of when he says   A flowgraph is reducible when it does not have a strongly connected subgraph with two (or more) entries
Isn't a directed cycle a strongly connected subgraph with more than 2 entries?
Comment: I explained that in my answer: an entry is a node of the SCC which has an edge coming from outside the SCC.

What is a reducible flow graph?