Why don't short-haul regional jets go for composites?

Question: We have seen Airbus and Boeing going all the way for composites on their A350 and 787, but when it comes to smaller planes like the Embraer E-jets or the Bombardier C-series, they choose to use aluminium, I'd like to know what are the reasons for this to happen, why is more cost-effective?
Answer: The C-Series has a carbon wing box.  The fuselage is aluminum but is a newer fairly exotic aluminum lithium alloy that is a bit lighter than 2024.  The decision to go with aluminum for the fuselage was mostly development and manufacturing cost (a fuselage requires a massive autoclave and it's development is fairly high risk the first time around) and ease of repair (the fuselage takes the brunt of vehicle damage on the ramp, especially on smaller aircraft) compared to carbon.
Cost is probably the number one driver.  They stuck with things like bleed air services, and wisely decided to avoid lithium ion batteries (Boeing had to use L-ion with the level of electric services).  The C-Series is overall a more conservative design than the 787, and it still almost broke the company, which was forced to give the airplane to Airbus for free or go under.
The E-jet is more or less the old 190 with a complete systems state of the art revamp (and I believe a new airfoil) that make it more or less a smaller C-series system wise without the risks of composites development.  An even cheaper choice, and a wise one on Embraer's part.
Answer: There are some all-composite business jets, like the newest Bombardier Learjet. The design choice is about trade-offs in manufacturing: supply chain, number to be built, available tools and workers, legal certification (old methods are considered proven so require far less testing data), existing techniques, cost/percentage of build flaws, market price of the end product, needed performance and lifespan.
Then there is a question of available qualified and certified after market mechanics for repair, inspection and maintenance. Downtime is required to repair minor damage like bird strikes and examine internal damage from loose carts or cargo that is a visible dent on metal but only looks like a scuff on composite but could be internal delamination. (Boeing had to consider and develop solutions for all of these external demands. Some solutions only made sense for large carriers with major maintenance divisions.)
For example, if a significant mistake is made on a lamination layer, the whole composite part is pretty much landfill garbage, while an aluminum panel or rib can be recycled and replaced as fairly low cost and effort.
On the other side, business jets like Lear generally have far different flight profiles over their life compared to commercial jets, operate at different cabin pressure, are more concerned with altitude and speed, may consider small airports a constraint, and pennies per seat mile is a much lower consideration. Cost of downtime for repair or inspection is a very different priority as well.
Then there are the aspects of fire, repainting (paint stripping specification), effect of fuel any that may leak into the structure, and of course weather certifications for lightning and icing conditions. For de-icing and anti-icing, aluminum can be easily warmed from the inside while plastic is a poor conductor and may need another method. For lightning protection the 787 has a metal cloth for the outer  layer and electrical bonding between all the parts, and this adds weight and thickness; as a percentage, a widebody jet is less affected by the extra material than a narrow body (the circumference doubles but the cross section area is quadrupled). Not all private aircraft are required to have full lightning protection. If they will not be flying near such conditions, maybe just the fuel tanks will have static and lightning protection. Also, useful payload is far less of a concern for business jets than for regional carriers who often sell extra baggage capacity to freight or parcel carriers like UPS/FedEx.
Comment: The Lear 85 was a train wreck from the get-go.  Some genius thought that they could build a carbon fuselage using normal commercial layup methods without using an autoclave, like making tennis rackets or motorcycle fairings.  Think of the cost savings.  It was a disaster and they had to start over.  Eventually the project was canned in 2015.
Comment: And on the other side is the Honda jet, all composite fuselage and considered quite a desirable plane.
Comment: That wasn't the only problem with the Lear 85 program...
Answer: The C Series has carbon in highly stressed wing skins and spars, so you have to restrict your question to fuselages if you want to be accurate.
While carbon is theoretically lighter for a given load, in fuselages there is a minimum skin thickness able to resist damage from things like runway debris and hail. It turns out that a narrowbody fuselage is way overbuilt when using carbon, so the potential of lighter weight is not realized. The higher cost of carbon rules it out.
A widebody has higher loads from pressurization of the larger diameter fuselage as well as bending from greater length. Such a fuselage can be made lighter than in aluminum as the required strength is well above the minimum gauge needed for damage tolerance.
Widebodies typically fly long segments, where every kilo of takeoff weight is multiplied by the fuel required to complete the flight. The fuel fraction (fuel/takeoff wt) can be as high as 45% so every kilo of airframe weight matters. Short haul regional flights are much less sensitive, with fuel fractions below 20%. Over the life of the aircraft a kilo of airframe weight is worth several thousand dollars to a widebody.
So widebodies are able to realize a weight savings from use of carbon, and have a flight profile that can turn the weight savings into a cost savings. Narrowbodies can't realize a weight savings, and couldn't reduce operating cost enough to defray carbon cost even it they were lighter.
Comment: @Koyovis Weight is important for anything that flies, that is true. I explained why it matters more on long haul flights (google Breguet range equation) which happen to be conducted by widebodies. Please explain what claim you object to and why.
Comment: Reducing empty weight is as important for a narrowbody as it is for a widebody. How do you quantify your claims?


How to run dual monitor with optimus

Question: I have reinstalled Ubuntu 12.04 to make a new attempt in getting the dual monitor working with my nvidia optimus. I already installed bumblebee.
But still it isn't working as it should. The monitor from the laptop has not the right configuration and neither has the external Monitor (which runs with VGA). And if I try to change the resolution I get black screens and can't do anything against it. If I reboot though the old settings are back. I have searched a lot for a solution and tried quite a few things but nothing has changed. Any ideas what I can do to get this thing working?
Answer: There are still issues to work out with optimus, like what David Airlie calls "reverse optimus" to make HDMI and other video outputs work straight from the nVidia card:
http://airlied.livejournal.com/76723.html
Please join this team if you are new by clicking on the "Join Team"
link at the right of the Launchpad page. It's important to have as
many users in the community as possible to request for appropriate
support, even if you found a non-obvious way to make it work for you.
Answer: Checkout my scripts to enable/disable external monitors:
Installation:

# You will need latest NVIDIA drivers installed. At the time of writing, version is 331.20.
# On ubuntu 13.10, it looks like this:
sudo add-apt-repository ppa:xorg-edgers/ppa
sudo apt-get update
sudo apt-get install nvidia-331

# Now we need to install bumblebee:
sudo add-apt-repository ppa:bumblebee/stable
sudo apt-get install bumblebee bumblebee-nvidia bbswitch-dkms

# Reboot

# Intel-virtual-output tool

# First, you will need latest xf86-video-intel driver installed (2.99). Ubuntu 13.10 comes with it,
# so you don't need to update driver in that case. However, what made all of this possible is the
# latest release of intel-virtual-output tool, which comes bundled with xf86-video-intel driver
# source. But, ubuntu's package does not bundle it, and we need to compile it from source. One
# MAJOR thing to note here is: DO NOT compile it from ubuntu's deb-src package. That package is old,
# and current release has some major fixes for the tool that we will actually need in order to have
# everything working properly. So lets do it:

sudo apt-get install git xorg-dev git autoconf automake libtool
cd /usr/src
git clone git://anongit.freedesktop.org/xorg/driver/xf86-video-intel
cd xf86-video-intel
./autogen.sh
cd tools
make
sudo cp intel-virtual-output /usr/bin/
sudo chmod +x /usr/bin/intel-virtual-output

# Install augtool:
sudo apt-get install augeas-tools

Write this contents to the file /etc/bumblebee/dual-monitor/disable.aug:

set /augeas/load/PHP/incl[last()] /etc/bumblebee/bumblebee.conf
set /augeas/load/Xorg/incl[last()] /etc/bumblebee/xorg.conf.nvidia
load
set /files/etc/bumblebee/bumblebee.conf/bumblebeed/KeepUnusedXServer false
set /files/etc/bumblebee/bumblebee.conf/driver-nvidia/PMMethod auto
set /files/etc/bumblebee/bumblebee.conf/driver-nouveau/PMMethod auto
set /files/etc/bumblebee/xorg.conf.nvidia/ServerLayout/Option[last() + 1] "AutoAddDevices"
set /files/etc/bumblebee/xorg.conf.nvidia/ServerLayout/Option[last()]/value "false"
set /files/etc/bumblebee/xorg.conf.nvidia/ServerLayout/Option[last() + 1] "AutoAddGPU"
set /files/etc/bumblebee/xorg.conf.nvidia/ServerLayout/Option[last()]/value "false"
set /files/etc/bumblebee/xorg.conf.nvidia/Device/Option[last() + 1] "UseEDID"
set /files/etc/bumblebee/xorg.conf.nvidia/Device/Option[last()]/value "false"
set /files/etc/bumblebee/xorg.conf.nvidia/Device/Option[last() + 1] "UseDisplayDevice"
set /files/etc/bumblebee/xorg.conf.nvidia/Device/Option[last()]/value "none"
save

Write this contents to the file /etc/bumblebee/dual-monitor/enable.aug:

set /augeas/load/PHP/incl[last()] /etc/bumblebee/bumblebee.conf
set /augeas/load/Xorg/incl[last()] /etc/bumblebee/xorg.conf.nvidia
load
set /files/etc/bumblebee/bumblebee.conf/bumblebeed/KeepUnusedXServer true
set /files/etc/bumblebee/bumblebee.conf/driver-nvidia/PMMethod none
set /files/etc/bumblebee/bumblebee.conf/driver-nouveau/PMMethod none
rm /files/etc/bumblebee/xorg.conf.nvidia/ServerLayout/Option[. = "AutoAddDevices"]
rm /files/etc/bumblebee/xorg.conf.nvidia/ServerLayout/Option[. = "AutoAddGPU"]
rm /files/etc/bumblebee/xorg.conf.nvidia/Device/Option[. = "UseDisplayDevice"]
rm /files/etc/bumblebee/xorg.conf.nvidia/Device/Option[. = "UseEDID"]
save

Write this contents to the file /usr/local/bin/nvidia-enable:

#!/bin/bash

sudo augtool --noload --file /etc/bumblebee/dual-monitor/enable.aug
sudo modprobe bbswitch
optirun true
intel-virtual-output

Write this contents to the file /usr/local/bin/nvidia-disable:

#!/bin/bash

PID=$(ps ax | grep Xorg | grep :8 | grep -v grep | awk '{print $1}')

# Kill the second X server.
if [ ! -z $PID ]; then
   sudo kill -15 $PID
fi

# Now you need to turn off nvidia card completely.
if lsmod | grep -q nvidia; then
  sudo rmmod nvidia
fi
sudo tee /proc/acpi/bbswitch <<<OFF
sudo augtool --noload --file /etc/bumblebee/dual-monitor/disable.aug
sudo service bumblebeed restart

Set perms:

sudo chmod +x /usr/local/bin/nvidia-enable
sudo chmod +x /usr/local/bin/nvidia-disable

Now you are ready to run: nvidia-enable and nvidia-disable to enable and disable Nvidia discrete card and external displays.
Original article that gets most of the credits.
Comment: Whilst this may theoretically answer the question, [it would be preferable](http://meta.stackexchange.com/q/8259) to include the essential parts of the answer here, and provide the link for reference.

How to run dual monitor with optimus


2001 honda civic with starter hesitation

Question: Recently my civic has had a slight hesitation of the starter when first turning the key on an occasional basis. Yesterday turned the key and nothing, it didn't turn over. Plenty of electricity. 1 hour later it cranked fine. The next day I stopped at a store came back out and again nothing. But turned it off tried again and a normal start. Previously I had tried multiple starts.
Comment: Intermittent no-crank problems are usually a sign of a starter motor that is on its way out. Can you confirm that the fuel pump is priming when you turn the key in the ignition?
Answer: You almost certainly have a Starter Motor problem. A small possibility is that you have a bad connection somewhere such as at the connection terminals on the Starter itself or possibly the Terminals on the Car Battery. A loose or badly corroded Battery terminal would normally cause other problems though such as a poor charging ability and therefore you would see a dead battery but this problem can be intermittent. Try having someone stand in front of your car. Turn on your Headlights. Turn your key as if to start your car. If nothing happens and your headlight dim a lot then you likely have a weak battery or a possible short somewhere. I am a DIY guy not a Mechanic but I would try this before I bought a new Starter as they cost "BIG" bucks for a Honda. Depending on the age of your Civic I would probably head to the Scrapyard for a replacement starter. Recycle/Reuse and most of all save a paycheck.


Is it hard to write Japanese?

Question: I see the Japanese symbols, but never asked myself how hard is to write using these symbols. It seems very inviable. How do you guys do when writing at Japanese? Is it really harder than, for example, English or Portuguese. I mean, the amount of writing required to express the same sentence.
Comment: I think most answers to this will be opinion-based, unless there is a study out there about saying sentences to Japanese speakers and English speakers and timing how long it takes them to transcribe them by hand.
Comment: [This question](http://japanese.stackexchange.com/questions/13155/japanese-language-compression-ratio) about "how much information is contained per character" may be of interest, though it focuses on characters rather than strokes or actual time to write.
Comment: As for handwriting, there are many booklets and correspondence courses for native Japanese, so it may need some training to write clearly. The same advice of Kaji - first try to write Hiragana - is effective, because Hiragana's rate in the sentence is high.
Comment: I think you guys have a problema with understanding the opinion-based concept. I do not think this is bad, instead I think is much more valid than scientism, since scientism is opnion-based on a unique person opinion, lol. Cant you guys see that ?
Answer: As I've explained when teaching, each language's quirks add value to it or else they wouldn't be retained.  If you embrace the differences by learning Kana quickly and then not being afraid of Kanji thereafter, it will come fairly easily with practice.  If you view kanji as a monolithic set of thousands of symbols with nothing in common with each other, you're going to have a hard time.
The trick with Kanji in particular is to remember that it forms a visual system of roots, prefixes, and suffixes that, among other things, enable you to guess the meanings of words you've never seen before or "coin" new words on the fly when needed.  Further, if you become acquainted with the breakdown of kanji as you learn them you'll discover patterns (visual, semantic, and phonetic) that create a useful web of knowledge for holding everything together.
In short, it's as hard as you choose to make it.
Comment: I see, learning a language is much more deep than I was thinking. I think you are right, if we never give it a shot, we will never know how it is like.
Answer: Like others have said this is highly opinion based.
I like to think of the structures as art works and have their own flow.
If you look up videos of japanese students and natives writing kanji and certain hiragana words, you can notice those little nuances that can make your writing legible to natives.
Think about why english (romanized language) was easy.
You learned young - were awful at the start - then a few years of schooling later you developed your own style.
It just takes practice!
What you can do to practice is make haikus on paper in all japanese.
It builds an understanding of the language and lets you write it out and practice.

Is it hard to write Japanese?


Probability of same Balls or same Numbers

Question: I'm really getting muddled over this probability question and will be glad if I'm assisted. '' There are 5 black balls and 3 green balls in a basket. The black balls are numbered 1, 2, 3, 4 , 5 respectively and the green balls numbered 1, 2, 3 respectively. If 2 balls are to drawn random without replacement, find the probaility that these balls have either the same number or same color.
So this was the equation I used.
p ( same color or same number) = p ( same number) + p(same color ) - p ( their intersection). How do i move on?
Answer: There are 3 ways that they have the same number.  There are choose(5,2)=10 ways of picking two black balls.  There are choose(3,2)=3 ways of picking two green balls.  All of those three events are disjoint so that gives 3+10+3 = 16 ways to meet the criterion.  There are a total of choose(8,2)=28 ways to pick 2 balls out of 8 without replacement.  So the probability that the 2 balls drawn at random without replacement have either the same color or the same number is 16/28 = 4/7.
Answer: There are $\binom{8}{2}$ ways to choose $2$ balls. These ways are all equally likely.
Now count the number of ways the balls can have the same number: Clearly there are $3$.
There are $\binom{5}{2}$ to choose $2$ black, and $\binom{3}{2}$ ways to choose $2$ green. So the number of "favourable" cases is
$$3+\binom{5}{2}+\binom{3}{2}.$$
Divide by $\binom{8}{2}$ to find the probability.
Remark: One can also use your analysis. Note that "same colour" and "same number" are disjoint events. They cannot happen at the same time, so the probability of the intersection is $0$.
The probability of "same number" is $\frac{3}{\binom{8}{2}}$. The probability of "same colour" is $\frac{\binom{5}{2}+\binom{3}{2}}{\binom{8}{2}}$. Add.
Answer: I prefer to solve this question by first finding neither nor condition.
The total possible ways= 8*7=56
For two balls to be having neither same color nor same number
Lets select the first ball from the basket of black balls and the second one from green balls
For 1,2,and 3 of black basket we have two possibilities each from green basket
For 4 and 5 of black basket, we have three possibilities each from green basket
So, a total of 12 possibilities
So our answer is 56-12/56 = 44/56 = 11/14


Can missing cage mount screws cause the frame to rust?

Question: I have a Cube Analog Disc 2012 bike, and recently discovered that I have no screws inserted in the bottle cage mounts. Is it possible for rust to form in this area? Also, is it possible for the water to enter inside the tube and develop rust on the inside (since there is no hole at the bottom of the frame, I believe water will remain inside until it clears off)?
Answer: It is possible for water or sweat to enter the frame, and for corrosion to build up. Any rust would be most likely to happen on the steel bolt (which is missing) rather than on the aluminum frame, but oxidization comes in many forms.
While this is unlikely to cause you any significant issues, it's an easy fix. Any M4 threaded allen bolt, between 1.5 and 2.5cm will fit just fine.
Stop by the hardware store or your LBS, and you'll be sorted in just a few minutes.
Comment: @linkyndy - As long as the bolts fit and turn smoothly, it doesn't matter if they're original equipment or not.
Comment: OK, I've seen a little bit of rust near the steel bolt and I thought my whole frame would be in "danger". I'll stop then and buy some bolts. I believe it won't be a problem if the bolts are not the original bolts which should have come with my bike, right?
Comment: The screws should be stainless steel and essentially rust-proof.  The main danger from water on the inside (even in a steel frame) is to the bottom bracket -- they can get quite rusty.
Answer: Your bike has aluminium frame, it can not suffer from rust. There is such thing as aluminium corrosion, but it is a very slow process, you bike will be fine for years.
But, of course, you better cover the holes. Cheap solution is a piece of tape, but you can either buy a bottle cage or any screws that fit there.


Colored item names in Minecraft?

Question: I came across a map and when I was playing I found some coloured and bolded item names. I thought it isn't possible as at most you can only use the custom name tag to rename things! Is there a way to colour and bold item names in vanilla Minecraft? External programs are OK. Oh, and the wiki page of formatting codes doesn't really do much.
Answer: You can use this page about formatting codes.
TL;DR use this in the name for colors

§0    Black
§1    Dark Blue
§2    Dark Green
§3    Dark Aqua
§4    Dark Red
§5    Dark Purple
§6    Gold
§7    Gray
§8    Dark Gray
§9    Blue
§a    Green
§b    Aqua
§c    Red
§d    Light Purple
§e    Yellow
§f    White

For example world name:
§1R§2e§3d§4s§5t§6o§7n§8e §9C§ar§be§ca§dt§ei§fo§1n§2s

Which results into:

You can use INVedit to edit your savegame and edit the characters in.
Comment: I need to rename an item. I can't input § in anvils or anything that rename things in vanilla Minecraft, so this answer does not really address the question.
Comment: Correct, I updated my answer to include the answer you were (hopefully) looking for.
Comment: ...Well, I think you misunderstood what I am asking. I am asking for renamed, coloured, bolded item names. Not world names and server names. An example will be an enchanted diamond sword with the name "The baddy sword" coloured dark red and bolded.
Comment: Correct, I was confusing MCEdit with INVedit. My bad. I only don't know for sure if INVedit can rename (and recolor) items.
Comment: INVedit also works!
Answer: In Minecraft 1.13, item names are now JSON, meaning that this no longer requires the use of the section sign symbol. For example:
/give @s stone{display:{Name:"{\"text\":\"Foo\",\"color\":\"green\"}"}}

will give you a piece of stone with the custom name of Foo colored green.
Answer: OK. Found an answer on the Internet while I was surfing. In Vanilla Minecraft, even with commands, you cannot colour item names. Instead... use MCEdit! There is a new MCEdit version created by TKTech and an modify item name string filter that can colour and bold stuffs by SethBling.
Source: SethBling's video
Answer: If you don't want MCEdit and just want to edit them (Even in anvils) use Text Formatting. It's a mod that allows you to paste the "§" Section Symbol (And other symbols you can't use in Minecraft). Here's a link for the mod:
http://spacechase0.com/mods/minecraft/text-formatting/
Comment: For me, when I put Text Formatting in my mod directory, up to the launcher everything works fine, and then Minecraft itself won't launch. No crash, no nothing. I've been monitoring what happens with Task Manager, and the javaw.exe of the launcher is present as usual, when I press Play Minecraft's javaw.exe appears as well, and a few seconds later both of them just vanish.
EDIT: Turns out I don't have SpaceCore yet. Weird that Forge didn't simply complain as usual.
Comment: Update: With SpaceCore, same behavior. Seems like Spacechase's mods cannot be loaded via Forge.
Answer: Unlike what everyone assumes, apparently it's possible in game, without any extra stuff. As it seems, NBT-formatted signs are able to inject § into commands by escaping it with \u00a7.
This online tool takes any command that uses § and converts it into a command that creates an NBT-formatted sign above the command block, with a click event that pastes the desired command into the command block. Totally crazy, but confirmed to work, at least up to 1.8 (broken in 1.9 and later, but only because of the strict JSON feature, that can easily be fixed manually by adding a couple of \" into the final command).
Note: The command that is being generated also omits all " characters, because the creator thought they are impossible to get in via signs. However actually they are easy to get in. Just find your escaped command in the generated command and add in \\\" where you want a " in the resulting command.
For everyone who doesn't like external tools much: The tool I linked doesn't modify your world saves. It's a command generator much like MCStacker. You get a command and paste it into your command block. Then you activate the command block, click on the sign that appears, and your command has the correct formatting.
(If you've done everything right, the text you wanted to format should have the formatting you chose inside the command block as well. If you didn't include §r at the end of the formatted section, the remainder of the command will be formatted as well. As long as no non-formatted text passages are meant to follow, this doesn't break anything.)

Colored item names in Minecraft?


What is the status of the psak of a Maharat?

Question: If an orthodox male Rabbi bestows semicha on a woman (dubbed Maharat), what is the status of her halachic decisions? This question is irrespective of whether or not the male Rabbi should confer semicha and whether or not the woman should publicly render halachic decisions. I am asking if, after the fact, Person X got a psak from a Maharat is that psak binding on Person X?
Comment: What does semicha have to do with getting an answer?
Comment: see http://judaism.stackexchange.com/a/7494/759
Comment: I wonder if it has anything to do with the relative authority of the rabbis who started the programs (R' Avi Weiss vs. R' Yehuda Henkin)
Comment: Why would the "psak" of a maharat be any different from the "psak" of any learned but unordained individual?
Comment: http://hebrewbooks.org/pdfpager.aspx?req=37519&st=&pgnum=60
Comment: I don't understand what the difference is between a Maharat (Yeshivat Maharat) and a Yoetzet Halacha (Nishmat) or why the latter is generally much more well-accepted than the former.
Comment: @Ze'evFelsen because she was ordained
Comment: @nikmasi Why would that matter?
Comment: @Daniel It might have to do with the learned-ness of those finishing the programs.
Comment: http://www.srugim.co.il/103131-%D7%90%D7%A9%D7%94-%D7%A9%D7%A4%D7%95%D7%A1%D7%A7%D7%AA-%D7%94%D7%9C%D7%9B%D7%94-%D7%90%D7%99%D7%9F-%D7%91%D7%96%D7%94-%D7%A9%D7%95%D7%9D-%D7%97%D7%99%D7%93%D7%95%D7%A9?di=1
Answer: The issue we have to ask is why is a psak (legal ruling) ever binding in the first place? Why can't you just ask the next person?
There are two main possibilities (see Shach YD 242:31):

שויה אנפשיה חתיכה דאיסורא The asker accepted upon themselves when they asked the first authority to follow their answer. Let's assume for now this principle works similar to a neder (see, though, Ketzos 34).
כבוד הרב The asker mustn't ask a second authority lest it impugn the honor of the first authority.

There a couple possible ways of testing this difference.
The Bavli (Avoda Zara 7a) tells that one may not ask a second authority (חכם) for a lenient ruling after receiving a stringent ruling from a first authority. The Yerushalmi (Shabbat 19:1 as understood by Rosh AZ 1:3) seems to say that one may not even ask a second authority for a stringent ruling after the first authority rules leniently. (Note: the Bavli doesn't explicitly reject the Yerushalmi's case; it just doesn't discuss it.) The Shach (at least) presents this argument in light of the two sides discussed above. Rama rules like Rosh's understanding of the Yerushalmi, while Shach disputes this, marshaling many, many authorities who ruled like the straightforward understanding of the Bavli.
If we take the first possibility, שויה אנפשיה חתיכה דאיסורא, then it seems there is little room to distinguish between who gives the psak, as the asker has accepted the answer upon themselves (provided of course there is no clear mistake made). If we take the second possibility, then we can distinguish between different authorities, depending on how much respect is due to a Maharat or other non-standard rabbinic authority. CYLO...A.

While I'm here it is worth noting that a women is certainly capable of issuing a "psak" if she is learned enough as is evident from the prohibition on issuing a psak after drinking wine. Sefer Hachinuch writes (#152):

ונוהג איסור ביאת מקדש בשכרות בזמן הבית בזכרים ונקבות, ומניעת ההוראה בכל מקום ובכל זמן בזכרים, וכן באשה חכמה הראויה להורות. וכל מי שהוא חכם גדול שבני אדם סומכין על הוראתו, אסור לו לשנות לתלמידיו והוא שתוי, שהלימוד שלו כמו הוראה הוא. כמו שאמרנו.
  And the prohibition of entering the Temple while drunk is in effect in the days of the Temple for males and females, and [the prohibition] or ruling [while drunk] [which Sefer Hachinuch counts in the same Mitzva - AA] is in effect in all places and at all times for males, and similarly for a woman who is wise and eligible to rule. And anyone who is very wise that people rely on his rulings cannot teach his students while drunk, for his teachings are like rulings, as we discussed.

When and to whom she should issue such rulings is, as you mentioned, not a part of this question.
Comment: related https://shaashuim.wordpress.com/2014/12/03/why-is-psak-binding/
Answer: There is an issue of serarah brought by rambam in hilchot melachim 1:5 that women cannot serve in positions where they would have authority or direct command over others. L'chorah, issuing a psak Halacha is a form of serarah, so even if a woman is learned and became a Maharat, she couldn't, according to this De'ah.
Edit: I didn't realize this was such a charged subject- or was my halachic analysis really that distorted? There is an idea called serarah, it is brought down in the rambam, it would preclude a woman from issuing a psak, and it would imply that if she did so then the psak would not be binding, which is what the questioner asked. Of course, there are those that disagree with rambam. I do find myself more sympathetic to the idea of a Maharat than not, but issuing psakim is a complicated idea, when serarah is involved.
Comment: "and it would imply that if she did so then the psak would not be binding" Can you source this inference? Or perhaps at least [edit] to elaborate why it is reasonable? It seems highly unreasonable to me.
Answer: Basically we have a rule, once chacham ("wise person") #1 has ruled specifically on your question, you're not supposed to ask chacham #2 unless you tell them your complete story. ("I asked chacham #1 and was told this, now how do you feel?")
My understanding is that this concerns actual ruling which requires making judgment calls on the case. If I call the Star-K and ask them "what bracha do you make on hearts of palm?" and they immediately reply "our policy is ha'etz", that wasn't a tailored ruling; if you really want to call the cRc and ask them, it's a bit silly but I don't think it's disrespectful.
As DoubleAA pointed out based on Sefer HaChinuch (and many great contemporary rabbis have ruled similarly), in theory a learned woman can render psak the same way a man can.
There are two remaining questions, really. Competence to render tailored psak, and communal structure.
The competence to render tailored psak simply depends on the knowledge and judgment of the person rendering it. You can't make a blanket rule about men or women with any given piece of paper. But please be aware that those who have spent much more time starting with the Talmudic theory and developing all the way through the sources can give a much better tailored psak than someone who was given some guidelines as a halachic digest. I don't know to what extent a Maharat is trained/authorized/expected to render tailored psak, and I suspect they'd be honest if you asked them this. Most yoatzot halacha, for example (including all those outside of Israel, as last I hear it), make no claims to issue binding psak, though they can consult a posek if needed. For instance, she could look at a bedika cloth and either say "this is obviously fine" or "this needs a judgment call, you need to speak to someone who can render psak." (A small handful in Israel have actually been given the advanced training to do so.)
Communal structure is a different issue; if my neighbor calls me up with a question that requires a judgment call, if there is a town rabbi who is available and competent to pasken then it's a good idea to direct the question to them. Ask me what happens to "communal structure" in a world where everyone just checks their own website instead, though; I don't know.
Comment: The issue of a psak only being on a given specific case is discussed in the Rama referenced in my answer.
Comment: so psak has nothing to do with serarah?


How do I jump onto really high stuff in Halo?

Question: I've seen people on top of really high things when there's no flying vehicles. How do they get up there?
Comment: Examples please? A few different places have different methods.
Comment: Do [Warthogs count as flying vehicles](http://www.youtube.com/watch?v=VCXpLIBCtew)?
Answer: Here is a list of pretty much every single jumping technique in Halo 3.
The main one I've heard of and seen used is grenade jumping, where you throw a grenade at the ground and jump just before it detonates, boosting the player character as a result of the blast.
Answer: Grenade or rocket jumping is how they do it.  You have to be careful and willing to take some damage depending on which version of the game you play.  It isn't very hard to do, but you do have to take some time to learn the timing.  The best way to learn it is to run a local game, load a multiplayer map and load up on rockets and grenades.  Then pick a place that has a high wall and time droping grenades onto the ground just in front of the wall.  Time the explosion and then work on jumping above the grenade just before it explodes.  You want to be just reaching the peak of your jump when the grenade goes off to boost you even higher.  You can do the same with rockets, but it has to be a bit more precise.  Practice a bit and you'll get it.
Comment: If you want to practise you can even adjust your sheilds, health, ammo etc so you can mess about to your hearts content in a custom game learning.  Still worth trying the techniques out with default settings as well to make sure a technique won't just cause you to suicide when you try it for real
Answer: There's a fun trick for the map Relic in Halo 2. You walk over to one of those black shields found along the edge of the island that you could use for cover. Stand on the bar on the ground connected to the shield and shoot a rocket straight forward at the shield. You'll be shot up pretty far into the air. If you have trouble with it, make sure you're standing on the part where the bar makes a 'T.'
One fun thing to do is melee the shield to move it. You can do this all the way until you get close to the huge tower. Then use the trick I described and you can get all the way on top of the tower.

Another method that is valid for most maps that have banshees is to fly really high in the banshee, position yourself over a high platform and then jump out of the banshee and fall onto the platform.


Collimator for Dobsonian, same as Newtonian?

Question: I have been looking on line for Collimator for my Meade Dobsonian. The only Collimators I can find are made for Newtonian Lenses. It's a 8" mirror with a 1.25" lens. Will this work for my telescope?
Answer: Yes, of course it will work. A Dobsonian is merely a Newtonian telescope on a special mount.


How does the voting for block producers work?

Question: How many votes can the user cast?
To how many block producers?
When does a change in the user's voting take effect?
Answer: Anyone who owns a EOS registered token can vote,You can vote and change your vote as many times you want.Each "staked" token can potentially vote for up to 30 different BPs. Votes are weighted by the quantity of tokens being staked.
The amount of votes you have is equal to the amount of staked tokens that you have. So for example, if in your account you have 35 staked tokens, your vote will have a power of 35.
Within your account, you will see two different states for tokens to be in; staked and unstaked. Unstaked tokens are free to be moved around, transferred to another user, or used to make another account. Staked tokens are what allocate for your account the amount of Bandwidth and CPU you are guaranteed access to on the EOS network.
The 21 Block Producers receiving the most stake-weighted votes get elected as active Block Producers.
You can change your votes many times, but each time you "unstake" a token, it will stay "locked up" for up to three days. So, for example, if you hold just one token, you can't vote for a different set of Block Producers every day.
Comment: If I vote for only 5 BPs, then I don't use the remaining 25 opportunities to vote my say 35 tokens, correct ?
Answer: You can vote for up to 30 block producers, and takes effect almost immediately. Each of your vote counts equally.
Comment: Isn't there something like 3 minutes time frame?


Is using "all" instead of "all used up" a regional thing?

Question: My inlaws from Central Pennsylvania will say, "The milk is all" instead of "The milk is all gone". Another very common example, "Can you bring me some cookies?" "Sorry, the cookies are all". Anyone familiar with the usage?
Comment: That usage can be found in several dialects of German ("die Milch ist [alle](http://de.wiktionary.org/wiki/alle#Adverb)"), so my first thought would be to check if this could be an import from [Pennsylvania German](http://en.wikipedia.org/wiki/Pennsylvania_German_language).
Answer: This was a common usage in the speech of the Mennonite families who lived around me in Southern Ontario (outside K-W; on my drivers license it just said G.C.T for German Company Tract) and we picked it up as children. The connection between the "Pennsylvania Dutch" (actually Deutsch) and the Ontario Mennonites is pretty straightforward. My poor mother still thinks that many Mennonite turns of phrase are stereotypically Canadian :-), including this use of "all".
Comment: Thanks so much! I might have guessed the connection to "Pennsylvania Dutch" and I think grandparents on both sides spoke Deutsch (I guess?) around the young kids if they wanted to keep adult secrets. I love that they use this actually, but my spouse always feels self conscious.
Answer: This is regional but more localized than geography. @Kate Gregory's answer is correct. My mother's family is from Philadelphia, Pennsylvania which is in the far eastern corner of the state. That usage, "all" instead of "all used up", is not standard there.
My grandmother and great-uncles moved to south central Pennsylvania, near Lancaster and  Harrisburg. In that very specific area, the"Pennsylvania Dutch" or "Amish country", I recall them saying that they heard many different usages of English at work. One was:

The milk is all

(or more importantly, "The chocolate is all").
My great-uncles spoke German and Danish, probably Yiddish but wouldn't acknowledge it, so they noticed these sort of expressions. Their rather heavily accented English was easily understood in this part of the state, which was a welcome change from Philadelphia.
Answer: Definitely regional.  I've never heard it here in New Zealand.  I've never heard it in any American, Australian or British movie or TV show.
Answer: The expression is still used in German today.
http://www.phrasen.com/uebersetze,Geld-Benzin-Brot-ist-alle,66383,d.html
Comment: Yes, and as RegDwight stated in his comment this could be the origin. Your answer, however, relates to the German language and this site is about English.


Bein hashmashot and bris

Question: If a baby is born "bein hashmashot" how do we count the days till the 8th for the bris? For example, if it's bein hashmashot Sunday evening, will the bris be the following Sunday or following Monday because you could say that since it's after shkiya that it's the following day?
Comment: "you could say that since it's after shkiya that it's the following day" Why could you say that? It's by definition a doubt
Comment: @DoubleAA you usually bring a source for example a mishnah https://www.sefaria.org/Shabbat.137a.20
Answer: The halacha is that bein hashmashot is safeik yom safeik lailah - doubtfully day or night.
In your example, bein hashmashot of Sunday evening is either Sunday day - in which case the brit is the following Sunday - or Sunday night (i.e. halachically Monday), so the brit would be the following Monday.
Because a brit cannot be performed earlier than  day 8, but is valid if is performed after the eighth day, the brit is held on the Monday (possibly day 8, possibly day 9), rather than on the Sunday (possibly day 8, possibly day 7).
(Source: Shulchan Aruch, Yoreh Deah, 262:4)
The major exception to this rule is if the baby is born bein hashmashot of Friday night. According to the logic presented, he ought to have his brit on the following shabbat (possibly day 8, possibly day 9).
However, the rule is that a shabbat brit only takes place if it is certainly the eighth day, not where there is a doubt. For this reason, the brit in this case happens on the following Sunday (possibly day 9, possibly day 10).
(Source: Shulchan Aruch, Yoreh Deah, 266:8)
Comment: Note as well that the night leading into Yom Tov has the same rule as Friday night. The night leading into the second day of Yom Tov though is potentially more lenient since many Rishonim allowed delayed Brit Milah to override the second day of Yom Tov.

Bein hashmashot and bris


MacBook Pro- wifi connected but no internet after unplugging ethernet

Question: I recently set up my modem/router through xfinity, and after activation I unplugged the Ethernet cord to try to connect my laptop to wifi. My phone is connected and working well but my laptop won't go online even though it's showing that it's connected to my network. I spent over an hour on the phone with Comcast troubleshooting, and we determined it has something to do with my computer. The computer was connecting to other networks just fine before I plugged in the Ethernet cable (it was the first time it ever had one plugged in) but now won't work on any wifi network including ones it had previously worked on. Help!!!
Comment: Check your wifi settings. DHCP should probably be set to auto, DNS empty (or with greyed out numbers provided by your ISP, or you can try 220.127.116.11 + 184.108.40.206), and your IP should be in the same range your wifi is if connected to the same network (most of the time).
Comment: Check in Network System Preferences.  What interfaces show in the left-hand column, and in what order?  You should have Wi-Fi listed first, with a green dot.  If Wi-Fi is not listed first, then it's trying to connect some other way, and failing, so you need to rearrange the service order.
Answer: Boot the computer to Recovery (hold Command and R on restart) and ensure it connected to your WiFi network. Then select Get Help Online. This actually loads a file stored in Recovery, so type in a URL and see if it loads. If it does not, your computer is not the issue.
Comment: Boot to recovery? Will I lose any files or anything?
Comment: No, recovery contains a set of utilities, one of which is Safari - listed in the menu as "Get Help Online". Another is a means to reinstall the operating system, but I'm not proposing you do that.


Does having too many content types negatively affect site speed and performance?

Question: I building a site that could potentially utilize 20 different content types. The content types are very similar, but may only utilize one or two fields that are unique to that content type, and they would use the same 5 fields with each other. Does having 20 different content types slow the site down? Would it be better to build one content type and display the unique fields on a case by case basis using FAPI or the conditional fields module?
Answer: The number of content types does not affect the performance of a Drupal site.
Sharing fields among the content types does affect the performance. This is because of the way CCK stores fields.

If the field is not shared and allows only one entry, it is stored along with other such fields in a table designated for that content type. That way, all such fields can be loaded in a single query.
If the field is shared or allows multiple entries, the field is stored in its own table, making an extra query (or join) per field necessary to load the field.
Comment: this should probably be the "correct" answer, the point is that having 20 content types will hardly touch your performance, but using Views to build outputs with shared fields will make your queries less efficient.
Comment: I think this is the most correct answer and confirms my initial assumption that the performance hit would take place in a view output. Thanks.
Comment: Note to readers in 2022 and beyond because this question ranks highly in some search results: This answer is about Drupal 6, and does not apply to Drupal 7+, which completely rewrote how fields are handled.
Answer: I would check out the performance of my database server and queries, web host, modules, and custom code before I would worry about having too many content types.
I have a few sites that have several dozen content types and they are screaming fast.  Some of these content-types contain 100,000+ nodes as well.
Answer: I can't think of a reason why many content types would dramatically affect site performance. Maybe if you build views that display data from many different content types, the queries would be a bit slower, but as Criticguy says, other factors are much more important.
That said... Things to consider before creating a large number of content types, are user experience and maintainability.
I don't know which users are going to create content in your site, but you have to make sure that those users understand the difference between the content types. A large number of types can turn out to be a huge threshold if the end user doesn't know which one he needs to accomplish his task.
For maintainability, it can be a lot of work if you have to alter all content types in a later stage. Something as simple as adding a field or changing the comment settings suddenly becomes a tedious job.
A way to avoid both problems described above, would be to create a single content type which contains all fields, and use taxonomy terms to identify the type of content. To improve the user experience, you could use the Conditional Fields module to hide and show certain fields based on the taxonomy term (or other form values).
Answer: You could also merge the content types that share most data fields and organize the "differences" into groups inside the manage fields section at Content/Content Types.
If it appears too unwieldy you could use the Vertical Tabs module to clean it all up and keep your users from feeling overwhelmed. http://drupal.org/project/vertical_tabs
I think simplifying the editorial flow for your authors is a good thing.
Answer: You are probably using 19 extra content types that you could save in different ways.
The first one, for example, using all the fields in the same, unique, content type, but giving the user the choice to fulfill them or not, depending on your/their needs.
The other is hiding the fields, using the nodeapi or a module like conditional fields: https://drupal.org/project/conditional_fields
Depending on the context, project, requirements, you could find other ways or solutions.


miRNA targets mRNAs

Question: If we observe that a miRNA, say hsa-mir-233, targets a mRNA, say XXX, in a given tissue in disease condition, can we say that always hsa-mir-233 targets mRNA XXX regardless of type of tissue and disease condition?
Comment: by tissue-specific, you mean miRNA may target mRNA in tissue A, but not in tissue B?
Comment: miRNA's can be tissue-specific, and their mRNA target can also be tissue-specific. I'd be careful about generalizing.
Comment: To avoid confusion, yes, the miRNA can be targeted to it's specific mRNA if it ends up in another tissue. To me there are some confounding factors that may alter it's *net* effect in different tissues or disease states.
Answer: First you have to define what you really mean by miRNA-X targets mRNA-Y. If you mean direct targeting then there are assays to verify it.
To verify if the miRNA can potentially target the mRNA independently, what is routinely done is a reporter downregulation assay (usually luciferase). You clone the 3'UTR of your target mRNA downstream of the reporter gene and check the activity of luciferase in the presence and absence of miRNA. You do that by co-transfecting the miRNA and the luciferase construct, collecting the cell lysate after some time (typically 12/24/36h post transfection) and measuring luciferase activity using bioluminescence counter. This just establishes the molecular possibility of targeting but does not really say if the same actually happens in a given tissue.
Reporter assays like this can be modified for in-vivo conditions too. Express the reporter-3'UTR construct in your organism (or specific tissue). Use another reporter with a mutated target site in the 3'UTR which abolishes miRNA targeting and compare the activities of the two. In zebrafish, people also use modified-backbone oligonucleotides (morpholinos) to mask the target site such that the miRNA can no longer target the mRNA. This assay is called target-protection assay.
There are other assays which do not involve reporter genes but actually capture miRNA and mRNA bound to the Ago-complex. This is done by protein-RNA crosslinking followed by immunoprecipitation of the protein (Ago) which is then followed by sequencing of the bound RNA. See this post for more details. These assays will give you tissue specific information but they only tell you if a miRNA and mRNA are bound together. They do not tell whether the mRNA activity is downregulated or not.
Targeting of the mRNA by miRNA, in-vivo (which has already been established by ectopic reporter assays) depends on many factors, the foremost of which is the relative concentrations of these molecules and the competitors. To produce an effect, the miRNA has to be in sufficient concentration for each of its target (if the miRNA has many targets then the per-target availability will go down).
So, if a miRNA-X actually targets i.e. downregulates a mRNA-Y in a specific condition, it need not do it in another condition. However, we would still say that mRNA-Y is a valid target of miRNA-X if it is so in at least one condition and better if it has been validated using reporter assays (ectopic).
Answer: mRNA targeting mechanism is highly specific and depends on various factors. the target mRNA and miRNA complex is highly conserved even from an evolutionary point of view.There are many in-vitro studies which shows the importance of miRNA concentration.Now under any kind of disease state the normal functioning of cells is hindered and this directly effects the level of transcription. the rate can either increase or decrease.
mRNA target region for miRNA in the 3'UTR region is highly specific, and its dependent on base pair complementarity between mRNA and miRNA, due to which the miRNA-mRNA duplex remains exclusive. there are multiple miRNAs which have been found for one particular mRNA, if u go through the database TargetHumanScan database(http://www.targetscan.org/) u will find many miRNAs for one particular mRNA, and vice-versa.
The concern here is not weather any mRNA can be regulated by the particular miRNA, but, whether its positive regulation or negative regulation which is needed by the cell at that particular diseased state.
Comment: miRNA hardly ever cause positive regulation. They are primarily repressors.
Answer: As well as the above, it's worth noting that the usage of 3' UTRs and polyadenylation sites can vary from tissue to tissue, so that an mRNA might have the cognate miRNA binding site in one tissue, but not another.

miRNA targets mRNAs


Screen capture software that can record 3D games

Question: I am wondering if there is a screen-to-video tool out there that can take good, professional-looking videos of 3D games. It doesn't necessarily have to be free. It must support Windows 8.
Comment: http://softwarerecs.stackexchange.com/q/4165/10687 has a list of free ones.
Answer: There are quite some the best ones are probably:

Fraps
xSplit
Open Broadcaster Software

Fraps:

Costs Money
displays FPS and has many other cool features
Trial version
Can make High Quality Screenshots
Can only record Games

xSplit:

Costs Money
Mainly made for LiveStreams but also good to just record Games
Can record Desktop

OBS:

Free, Open Source
Mainly made for Livestreaming, but records just as well
Can Record Desktop
Answer: For video games, you can use Fraps:

Straightforward to use
light
non-free
you can change the FPS and the resolution
Windows 8 (game capture only)
Answer: I've streamed for a long time now and I've always used

XSplit if I need a specific UI (ads, banners, text, webcam). It's pretty good quality and not that resource heavy. You'd use that for livestreaming, or very long videos (playing diablo in HC and wanting to have the moment of your death on video)
Fraps : Basically captures everything that is in the current window. Uncompressed, videos are really heavy, and the software itself is also resource heavy. But the uncompressed video is really good and you can do any editing you want afterwards. This is what you'd use if, for example, you'd want to record Raids in wow. Record, then edit, then publish.
(NVIDIA USERS ONLY) Shadowplay : This is amazingly good and very, very VERY light. Only works for nvidia users since it's a built-in software that does pretty much the same as Fraps but without the lag. If you have an Nvidia card, use that instead of fraps.
Answer: I recommand D3DGear, a very fast game recording software for 3D games.

[It] allows users to record game play to movie without slowing down the game. D3DGear software has very minimal performance impact on the game and may not cause a game to lag or drop frame rate.
D3DGear software recording produces high quality video with small file size, and it supports microphone recording, Push-To-Talk recording and face camera overlay[...]

It comes with a 15 day trial. The full version costs $34.95
It supports Windows 7 and 8
Comment: Thanks, Timmy – I was just about to complain about missing details ;)
Comment: @Izzy I'd hate to see a valid solution get deleted for being in a low quality answer, and the information was there on the website
Answer: I like Loilo. Features that you might like include:

Free
No watermark unless you use the trial editing software. (In my case I plan to use Windows movie maker when the trial is over)
You can record as long as you want I record pretty long videos.
For me I found it seemed to use less resources then Fraps and Bandicam when recording. May depend on settings of all software)

I tried a few others and this was the only one that seemed to work well. The only caveat is that it comes bundled with a trial for video editing software.
Answer: Dxtory
The steam gaming client has a built-in streaming option.
The AMD video drivers has a built-in utility.
NVIDIA has shadowplay


How can I improve these secondary pages without a radical redesign

Question: I am more of a web developer than a web designer so I would appreciate it if I can get some tips on how to improve http://tinyurl.com/7my6g6m 's design/looks and other secondary pages on this site. Always easy to see that it isn't right, but it is harder to make design changes that improve it.
Client wants to keep the homepage, but wants to improve the overall look and readability.
I was considering making the pages wider and us better padding, drop the top header title block and perhaps use less top navigation items.
Any tips you can give the client/me ?
Answer: When it's hard to figure out what to change about a design, you have not actually defined what is wrong. That it is wrong my be obvious. Why it is wrong is where you find the answers to "How do I fix this?" Exactly identifying a problem (in life, as well as design) gives you its solution.
In this case, there's a great deal to fix, but the huge, glaring problem is that the layout and the information hierarchy have no connection with one another. That enormous, sickly green box is visually the most important element on the screen. It's so dominant that it rivets the attention, but the only thing in it is a headline that fills less than one quarter of the box! Two entire sidebars contain one redundant paragraph apiece. The major navigation items from the home page are squished a into tiny, unreadable, misaligned mess.
Meanwhile, get rid of the left sidebar and expand the content div. Use the right sidebar for all those topic squares, if they're in love with them, two across or single stack. No silly text paragraph. Get rid of the gruesome yellow-green box. Mock up a nice big heading for each of your secondary page main content divs, perhaps along these lines:

Align the top nav to the left. The eye doesn't catch it when it's aligned right, so it feels awkward and looks like a mistake.
Try to convince the client that enclosing every element of the page and the page itself in a set of Chinese boxes is unnecessary. The information won't break loose or run amok through the site, visiting mayhem upon innocent subheads and frightening away visitors. It will stay where it's put.
Lighten things up. The depressingly dark scheme adds to the offense of boxing everything.
Recycle (as in mulch) the stock images. They are frequently ambiguous, like the one on the testimonial page: is that supposed to represent the company or the customers? Are they the actual people -- you and I know they're not, but the average visitor won't -- or not? At the very least, use unambiguous images or (as in my example) images that don't pretend to be the real thing.
Best solution: bring in a designer you can work with. Surely they can afford one? There are lots of smaller items that also need fixed to make the whole thing look professional, which a designer will address as a matter of course. I'd suggest to your client that their clients, and the clients they're looking for, expect a high end site. It's part of being credible, and being able to charge big bucks for your services.
Comment: Thanks for all the tips Alan and Krazer. I appreciate it a lot. I will talk to the client again today or later this week.  As soon as I have made progress on this I will post back. Thanks again!
Comment: Just a little update. Going to add all content to a test server with a new theme which will incorporate the homepage, but which will have a greatly adjusted layout for all the secondary pages. Thanks again for these great tips!
Answer: Stuffing your navigation in the upper right corner really draws attention away from what is perhaps the most important part of the site, the navigation. Make sure your navigation is consistent across all you pages. Arrange similar pages under the one general page that lists similar subpages (e.g. under business and translation services, you can have links to "modern languages" and "business training"). Work out a site map  and add better navigation  to indicate to the user what section of the site they are on. (e.g., are they looking at a page under "news", "business support", or "clients"...?)
Establish where you want your navigation (home, programming, training, etc) to be. I recommend along the left hand side.
Unless you have special dedicated content you want to distinguish you don't need as many columns as you do.
Stick with a 2 column layout: left column for navigation, the right column for the header/body content.
You can merge the content currently in the lower right column (e.g. We provide comprehensive training[...]) in with the header as a subheader to give context to each section.
You can take what's currently in the left column and replace it with navigation box, currently on the top right column. Make sure you lay it out so it's link per row so a visitor can easily distinguish each link. Currently, the navigation box looks like some sort of decoration. As for the content that is not in the left column you can add that to the body text, as an introduction to what you want to talk about in that section (much like for the header, but before all the body text).
Try to work with div layers instead of static tables, it gives you much more flexibility in terms of formatting.
Identify your ideal screen resolution, and then use to do see how much space you have to work with.
Comment: Thanks for the tips Krazer. These tips will help a lot! Will add feedback again as have more news.


Scaling location points proportionately

Question: I'm trying to get QGIS (1.8) to scale the point markers for each town in a district proportionately to the size of their population (i.e. bigger population = bigger circle). I can get them to vary by colour by graduating the properties for the layer with the population data. When I try to use Advanced>size scale field function though I either get nothing or the entire screen goes one colour. I've not found a way in QGIS to scale by size only which is what I really want to do. Ideally I want the circles to graduate in size only and to have the same colour. I'm hoping that there is a straightforward way of doing this in QGIS.
Answer: Advanced - Size Scale field is the correct way to go. Note that the size you specify in layer properties is multiplied by the value in the attribute field that you choose. Therefore you might want to calculate a new size scale attribute field e.g. dividing population counts by 100,000 or a million.

Scaling location points proportionately


Would hydraulic disc brakes be easier on my hands than mechanical disc brakes?

Question: I ride MTB in a coastal town where all roads are dirt roads with lots of uphill/downhill. Nothing extreme, I just ride to relax and enjoy the landscape. I have mechanical disc brakes and after a 2-4 hours ride session my hands hurt (too much braking). I have never ridden with hydraulic brakes, but it seems to me that they will be easy on my hands. Should I change to hydraulics?
Comment: Brake lever pressure vs stopping force is a function of mechanical advantage and pad/disk composition.  You can get the equivalent mechanical advantage with hydraulics, cables, or even rods and levers.  Hydraulics have the advantage that there's a hair less friction in the mechanism, and generally less "slop", which would allow for brakes to be set up with less "pre-travel" before they engage.  But this advantage is largely negated with proper maintenance.
Comment: You say your hands hurt from too much braking, but braking fatigue ("arm pump") hurts your forearms, not hands.  Painful hands tend to result from poor gloves, grips, posture, etc.
Comment: The difference between mechanical and hydraulic disc brakes (or v-brakes and cantis, for that matter) shouldn't equate to more or less usage. Either your disc brakes need to be serviced, or your issue is more a result of bar setup and body posture. Could you describe a bit about the brakes (age, brand, whether they've been serviced...) and a bit about your setup (i.e. resting lots of weight on your hands and wrists).
Comment: Brakes are Shimano Alivio. Age 3 or 4 years (bought second hand). I have made near 2.000 kms. Never changed pads; they look good to me. They work well; just need lot of pressure for complete stop while running downhill (~30-50 k/h). I changed the cable casing for a new one (teflon inside). My handlebar is narrow (shoulders wide) and my setup oriented to minimize weight on my hands and get an upright position (I weight 100 kgs). As I said, I enjoy looking the landscape. I do basic maintenance myself, but take it regulary to my mechanics.
Answer: I have or have had bikes with mechanical rim brakes, mechanical disks (shimano deore), hydraulic discs (also shimano deore) and recently hydraulic rim brakes (Magura hs33).
The experience I had says that:

The force you have to apply depends on brake-system preload / elastic constant (lever spring + actuator spring), cable friction, and actual, braking, pad friction.
Pad friction means how much decelerating power you'll get for a certain force applied by the pad against the braking surface. Good quality pads brake more with less force. Bad quality, or dirty, or whatever-else-not-ideal pads require more force to get the proper braking power.
Cable friction means, the more cable friction, the more force will be irreversibly lost between the lever and the actuator. At extreme cases, with very dirty/rusty cables, you get enough friction that you get an absolute maximum beyond which no additional force on the lever creates aditional force at the braking surface. THIS IS THE MAIN PLACE WHERE HYDRAULICS MAKE A DIFFERENCE: they always have a very low (inexistent?) cable friction, and that doesn't change even after miles and months in the muddy rain, for example.
At last, system preloads mean the force you have to apply to the system BEFORE it even starts to break. For example, my Magura HS-33 has too much preloat at the lever, and if you ride lightly, only correcting speed now and then with the brakes, even so the hand gets tired, because even for a slight touch you have to overcome half the lever course of a relatively stiff spring preload, whereas on modern, race-oriented disc systems the lever action is so light that it seems like there is no actual brake connected to the lever (at least until the pads hit the disc, of course).

So, I'd say the hydraulic systems are well worth the upgrade, but unless some facts are taken into consideration, sometimes the magic might not happen, specially if the braking pads are not doing their job. Also, a v-brake with new and well tuned cables/cable-routers, killer pads and decent levers can beat most fancy disc brakes around.
Hope this helps!
Comment: "Also, a v-brake with new and well tuned cables/cable-routers, killer pads and decent levers can beat most fancy disc brakes around." - Until it rains.
Comment: @cmannett85 Yeah, that's why I wrote "can beat" instead of "will beat" or "will ALWAYS beat"... I see a case for rim vs disc brakes, but the world would be a much happier place if hydraulic actuators (instead of wire cables) were the default for bike brake systems...
Comment: "HYDRAULICS MAKE A DIFFERENCE: they always have a very low (inexistent?) cable friction"... Close but no cigar. When you apply pressure at the lever, a certain volume of fluid need to move before pad contact occurs. The flow will be proportional to the pressure and the *hydrodynamic resistance* calculated from the radius and length of the channel (hose). *Hydrodynamic capacitance* also exists when fluids are compressible and/or the channel has elasticity. https://en.wikibooks.org/wiki/Microfluidics/Hydraulic_resistance_and_capacity
Comment: @Emyr Yeah, you are right, I guess I meant _static_ friction... Anyway, compared to a sub-optimal cable, the friction is much lower.
Answer: I'd recommend giving your current brake installation a good service before considering spending money on an expensive upgrade.
Hydros are great (I have them on my bike and enjoy riding with them), but a well-maintained braking system should be more than adequate in all reasonable riding conditions.  Hydros would have advantages if you're into mountain riding as a sport, but for day-to-day use you probably won't notice much difference.
You say you've never changed your pads because they work.  A pad can last a good while to be sure, but they do tend to become gradually less effective as they wear (more force for the same braking needed).  You might want to look into changing the pads for fresh, good quality ones.  That should give an noticeable increase in breaking power.
Similarly, the discs or rims that the pads press against can wear, though that's very unlikely to be a factor unless the brakes in question are very old.  What is more likely to have an impact is dirt and other contaminates on the braking surface.  Mud and dirt, lubricating oil from your bike, the remains of old brake pad material and what have you can build up on the surface.  If you clean the surface thoroughly then you should notice further improvements in the stopping power of your brakes.
The cable in mechanical systems can stretch, fray, rust and so on.  As it's a mechanical moving part it also needs to be properly lubricated.  As the cable stretches with use you should adjust the brakes to counter.  You should also apply some kind of lubricating grease or wax to the exposed portions of the metal cable with the brake in both the released and applied state.  Finally, if there's any sign of rust or fraying in the cable, get it replaced immediately!
All this maintenance should make a very noticeable improvement in the stopping power of your brakes.  More effective braking means less effort needs to be used when braking, and hopefully less strain being put through your hands.
You may also want to invest in a good pair of padded cycling gloves, they also offer a measure of protection from strain on your hands.
If none of the above helps enough then that's the point where you might want to start seriously looking at replacing your brakes.  However, doing the above is likely to be effective in reducing the amount of effort you need to apply when braking, and it's a lot less expensive then replacing the brakes on your current bike.
Answer: In order to brake you apply force on the brake lever that is then transferred to the braking surface (e.g. disc and pads).  The advantage of hydraulics is the efficiency in which force is transferred (i.e. reduced system flex).  Cable actuated disc brakes will have more compression  in the cable housing, resulting in reduced efficiency and potentially tired hands from the extra force applied during extended braking.
That said, you can greatly improve cable disc brake efficiency by upgrading the cable housing to "compression less" housing (e.g. Avid Flak Jacket).  This could be a much more cost effective option than switching to hydraulics.  I did this on my commute bike and the performance was quite close to hydraulics, but did take some time to properly set up.
Answer: I had some Shimano XT hydraulics on a mountain bike, and now have Avid BB7 mechanical disks on my touring bike.  I don't know whether to attribute it to the lack of cable compression or some other mechanical advantage, but there's no question that the hydraulics feel much easier and controllable.  It is also a more linear feel (or "better modulation" is a phrase I sometimes hear used) -- you get more braking right at the beginning of the lever pull because you don't have to first squish out all the flex in the cable and cable housing.
By contrast, my mechanical disc brakes, while very strong, have a bit of squish at the beginning, and don't subjectively feel as nice.  I still choose not to run hydraulics because of the increased vulnerability (hydraulic line punctures) and difficulty of doing field repairs (particularly inappropriate for a touring bike).  But the hydraulics, subjectively, definitely feel much stiffer and stronger.  Since you're a bigger guy at 100 kilos, and braking quality sounds important to you, I don't think you'd be crazy to want to try switching over to hydraulics to see if they make a significant difference.


How was the Spanish Armada coordinated?

Question: We know that the Spanish Armada was composed of over 200 ships. How did the Duke of Medina exercise any sort of control over a fleet this big with only 16th century technology? Do we know how the ships passed commands to each other and anything about how it was organised? Did this command structure contribute to the eventual shipwrecking of the majority of the fleet?
Comment: Flags and horns - same means as the fleets of Nelson fleet and Thucydides.
Comment: Including some of your sources would improve the question. For example, what are you including in your estimate of "over 200 ships" ([wikipedia](https://en.wikipedia.org/wiki/Spanish_Armada) suggests there were only 130)?
Answer: There's very little concrete evidence about how command and control of the Spanish Armada worked, or indeed, how naval tactical control was exerted during that period, which pre-dates what we now call the Age of Sail.
Most of the documentation that has survived from the Armada is correspondence that is essentially at the political level, i.e. between the King and his commanders. So we know at a strategic level who said what and when but don't know in any detail how, and if, these orders were transmitted down the chain of command.
We do know that the Duke of Medina Sidonia wasn't a naval man whereas his second in command, Juan Martínez de Recalde was an experienced Admiral in the Spanish Navy. This lead to some friction between the two because the Duke insisted on sticking to King Philip's plan of attack, while de Recalde would have prefered to have dealt with the English fleet (especially when the opportunity arose to attack them in the Solent).
At the time of the Armada, the standing national navies of the European states were quite small and there were few professional naval officers. As can be seen from the make up of both the Spanish and English fleets, the actual number of warships on both sides is dwarfed by the number of armed merchants and transport ships.
This greatly limited the tactical options available to both sides. Even relatively simple fleet maneuvers require coordination and practice to pass off without incident. Trying anything too complicated when most of your ships have little or no fleet experience is risking collisions or worse.
So what methods were available to pass orders?

In person - The subordinate officers could meet the commander on his ship to receive orders. This allowed commanders to discuss strategy and tactics at a detailed level more quickly than would have been possible with any other method.
Written instructions - These could be strategic communications, passed by despatch boats back to Spain and ahead to the Duke of Palma, or tactical communications within the fleet passed by ship's boat. These were most useful for passing more complicated orders than flags, guns or lights could transmit.
Flags - While this seems an obvious method, it must be remembered that there was nothing like the signal codes and fighting instructions that were common to the professional navies of the late 17th and 18th Centuries. Flag signals would have been limited to pre-arranged orders such as "attack", "withdraw", "follow me", "anchor here", etc.
Guns - Signal guns used in much the same way as flags to pass pre-arranged orders. They had the advantage of being useful at night or in poor visibility but were, obviously, of little use during a battle.
Shouting - Orders could passed ship to ship by voice when they were close enough. This could also be used when sending a boat between ships to avoid any tricky transfer between boat and ship. While this method was limited in range, it did allow for more complex orders to be passed.
Lights - Useful at night but even more limited than flags and guns in passing orders.

Did the problems of tactical control contribute to the failure of the operation and the loss of ships on the return? Certainly control over the fleet was never fully re-established following the flight from Calais but bad luck and poor navigation played a larger part in its losses.
It was never part of the plan for the fleet to sail around the British Isles to return, so I'd imagine that the maps available for that part were more rudimentary. By the time they reached the open waters of the Atlantic many of the ships were in poor condition and were barely sea worthy. The relatively primitive navigation aids of the period meant that they failed to establish their position accurately. As a result, they ended up turning south far too close to the British isles. This, combined with unusually bad weather, lead to a large number of losses on the Scottish and Irish coasts.
<code>ref: Naval Warfare in the Age of Sail, Brian Tunstall (Conway, 1990)
     Fighting Instructions, 1530-1816, Sir Julian Corbett (NRS, 1905)
</code>
Comment: In regards the return voyage of the Armada, recall that the longitude problem had not yet been solved and the Spanish were in ***very*** unfamiliar waters north of Scotland. The gulf stream had been carrying them north and east as they attempted to sail due west, so they were much closer to the Scottish and Irish coasts than intended when they turned south. Once on the lee shore of a prevailing South-West wind, only the very best crewed ships had any survival chance.
Answer: For battle plans and such, they used dispatch boats (which they then called "Aviso" or "Adviso", as in advice boat). These would carry orders from shore to ship and from ship to ship.
For manoeuvres, like Pieter said: flags and horns. Lanterns at night for guiding purposes – as seen here, resulting in a scattered English fleet when Drake snuffed it for more discretion – rather than as a means of communications. (Use of optical telegraphy is speculative.)
As to whether or how the command structure contributed to fleet's destruction, I've honestly no idea. But as I understood things, the 1588 armada was primarily defeated by superior English manoeuvrability, superior English seamanship, and unusually strong North Atlantic storms. There admittedly were some issues related to communications (e.g. awaiting the Duke of Parma in a fixed rendezvous point, communications taking time), but none seemed attention-worthy.
Answer: The Manchu Dynasty used flags to coordinate their massive Armies which conquered all of China in and around 1600. Since the Portuguese had already sailed as far by then it is interesting to speculate that Europe had developed an advanced system of "flagging techniques" prior to the Manchu...and perhaps used in this engagement which lasted for some time. (Weeks? A month?) The most obvious way to communicate is through a written order committed to memory then discarded (burned) then there would be no record of any communication system being employed. That would appear to be the case here. In other words "verbal commands" literally given in person on the Commander's ship to the Commander personally. After the failure to land at London a "frag order" or change of command would have to have been given in this instance since it made no sense for the Armada to sail North around Scotland then West into the Irish Sea which ultimately doomed the Fleet. Great Britain did attempt a counter offensive by landing in Lisbon, Portugal...but this was a disaster for Great Britain as well. After that "flagging your vessel" became a signature item for maritime law and seamanship. The most valuable possession on board a ship after the Spanish Armada was usually the bill of lading. That, a sextant and a "map" was about all that a sailor needed to "go exploring." Having familiarity with the terrain was of great advantage to the European Powers for centuries as outside of the later United States and Canada there were no "shipping powers" in the New World save for maybe the Maya. That's true in the Americas even today actually. This is certainly not true in East Asia anymore though.
Comment: I'm not sure this answers the question.
Comment: The Spanish Armada sailed forth to Britain in the shape of a Crescent. This would have been agreed upon in advance as well as it's Mission...namely to link up with the very large Spanish Army that had conquered and occupied the Dutch Lowlands. The Royal Navy attacked out of Plymouth in line formation "raking" the the much larger Spanish Fleet and Ships both fore and aft...then achieving the superior I think it's called "leeward" position behind the Spanish Crescent and the wind at both their backs with the Royal Navy "behind" but able to close with the slower Spanish ships. No comms needed
Answer: First of all, the man that was elected to command was Alvaro de Bazan one of the most skilled and prestigious admiral in Spanish History. This admiral son of Basques as his father´´ he became an admiral of the Spanish navy. In other words, the best man to lead an invasion England with experience against French and Turkish navies with great victories. He maid even an expedition plan very well prepared, however, he died a month before the plan was completed.
Was known that even Alvaro, the admiral, told Philip II that he needed more time to prepare fleet something that the king saw badly and pressured him to finish as soon as possible.
After, the died of the veteran admiral, the Spanish navy received a very bad news because he didn't have any other admiral to lead the fleet. Only the skillful captains in many warships.
Phillip decided for Duke Medina Sidonia, a man with few skillful in Italy as a land officer. Even, the duke tell the king that he was not the right man to command due to his non-experience at the sea, even he didn't like the sea.
Did you imagine a general commanding a fleet?
Spain will not a have a good admiral in the fleet until XVIIIth century. Philip was forced to use the captains with his warships without using a large scale group of ships. Something that have temporary success like the sack of Cornwall and many others.
In the imperial Spain, was necessary to have a good fleet in order to transport the tercios the finest army of those years.
Many times tried to invade  England but always the plan failed due to the storms.
In the early XVIII. century, with the fleet rebuilt and with good naval officers tried to defy English power. Even was near to get success. Spain planned a rebellion of Scotland having his heir protected by strong 300 Spanish soldiers. The first part of plan was achieved, however, the second part of the plan failed. this second part was an invasion of west England with Spanish fleet transporting an strong Spanish Division  with admonition and weapons for 3 divisions (in order to join volunteers in whole British islands) in order to invade England. However, due that the Atlantic oceans had strong storms the Spanish admiral decided to stay at the Spanish port provoking the delay of the mission. At the England only fought against Scotland and the 300 Spanish soldiers abandoned.
Later, after Napoleon invade Spain having his navy and army under his control forced them to join the fleet with France fleet against the royal navy provoking the destruction of the complete Spanish fleet.
Comment: This doesn't answer the question. In fact, half of the answer doesn't even address the Spanish Armada.

How was the Spanish Armada coordinated?


Installing ubuntu on a formatted NTFS drive

Question: I am supposed to fix a laptop in which the hard disk was recently formatted. It contained Windows 7 before.
I am trying a fresh install of ubuntu 12.04 from a bootable USB, but haven't been able to go past the maintenance shell.
In the maintenance shell, I tried out the following:
root@ubuntu:~# ntfsfix -b -d /dev/sda
Failed to determine whether /dev/sda is mounted: No such file or directory
Mounting volume... NTFS signature is missing.
FAILED
Attempting to correct errors... NTFS signature is missing/
FAILED
Failed to startup volume: Invalid argument
NTFS signature is missing.
Trying the alternate boot sector
Unrecoverable error
Volume is corrupt. You should run chkdsk

The trouble may be that there aren't permissions to write on the ntfs partition. The partition might not be corrupt. When I check the filesystem, I get this:
root@ubuntu:~# fsck /dev/sda
fsck from util-linux 2.20.1
ext2fs_check_if_mount: Can't check if mounted due to missing mtab file while determining whether /dev/sda is mounted. Bad magic number in super-block
The superblock could not be read or does not describe a correct ext2 filesystem.

So, it must be an ntfs file system. that's why I tried ntfsfix but that didn't work.
The hard disk is not partitioned. When I run
fdisk -l

it shows /dev/sda (~500 GB) and /dev/sdb (boot recovery) .
I have been trying to run
badblocks -v /dev/sda

But, suddenly the laptop just reboots and I don't even get to the maintenance shell stage.
I select "Install ubuntu" and it gets stuck at the wait screen forever.
Please help!
Answer: Try /dev/sdaX --> X is a number from 1 to n.


What is the necessity of Obstacle Departure Procedure(ODP)?

Question: What is the necessity of Obstacle Departure Procedure(ODP)?
Standard Instrument Departure(SID) is enough, isn't it?
Comment: [This question](https://aviation.stackexchange.com/q/1081/62) is closely related, but it doesn't address the difference between an ODP and a SID so I don't think it's an exact dupe
Answer: Departure procedures are way to get IFR traffic from the airport to the en route system. There are four different procedures.
If an aircraft may turn in any direction from a runway within the limits of the assessment area and remain clear of obstacles that runway passes what is called a diverse departure assessment and no ODP is published.
There are a few in Kansas and Nebraska but  Florida, which is also pretty flat, only has a couple at military bases.
Obstacle Departure Procedures (ODP) are only used for obstruction clearance and do not include ATC related climb requirements. They often have higher visibility minimums and climb rates greater than 200 fpnm. Most are given as text, though occasionally there are graphical representations of them. They frequently have other restrictions, e.g. the tower must be open and monitoring a VOR, not available if local altimeter setting is not available. All but a few airports have an obstacle departure procedure.
A Standard Instrument Departure (SID) is an ATC-requested and developed departure route. Pilots must have at least the textual description of the procedure. SIDs always have a graphical depiction. Unlike Obstacle Departure Procedures, SIDs usually have portions where the altitude is restricted—either minimum or maximum. Most SIDs have multiple transitions to get you into the en route system. Small airports generally do not have SIDs and most airports that have scheduled air carrier service have at least one SID. While the primary purpose of a SID is to ease pilot and controller workload while getting the aircraft into the system, they also provide obstacle clearance.
A visual climb over airport (VCOA) is a departure option for an IFR aircraft, operating in VMC equal to or greater than the specified visibility and ceiling.
A radar departure is another option. They are established when ATC has a need to vector aircraft on departure to a particular ATS Route, NAVAID, or fix.
All departures (except VCOA) assume that the aircraft will cross the departure end of the runway at 35' or more, continue on the runway heading until reaching 400', and climb at a rate of 200 feet per nautical mile. Standard minimum visibility applies, 1 mile for 1 and 2 engines and ½ mile for 3+ engines.
You can read more about departure procedures in FAA-H-8083-16 Instrument Procedures Handbook, Chapter 1 Departures
Answer: Edited because I'm a moron and missed the intent of his question...
This gets deep into the weeds of Pt. 25 vs. Pt. 91 vs. Pt. 135/121.
First off, SIDs are intended for normal all-engine climb to transition from the terminal area into enroute airspace. They aren't specifically designed for obstacle avoidance though it is an important consideration. They don't account for obstacles within the first mile of the runway end, so just relying on SID gradient doesn't protect you against close-in obstacles.
I cribbed this from the FAA Instrument Flying Handbook regarding ODPs:

If an aircraft may turn in any direction from a runway within the
  limits of the assessment area and remain clear of obstacles that
  runway passes what is called a diverse departure assessment, and no
  ODP is published.

So ODPs can be created in conjunction with a SID if obstacles are a problem. "DUH" on my part...
Engine-out ODPs are created by individual operators (airlines etc) and intended only for use in an emergency: engine failure post-V1. It's easier if the engine-out path mirrors a SID, but it doesn't have to. Vertical obstacle clearance is less stringent than SID, but the 0.8% gross vs. net margin (assuming we're talking twin engine) provides a steadily increasing pad over distance.
SIDs/ODPs vs. engine-out ODPs is probably one of the most misunderstood subjects I've encountered in this business. The other is conflating "Climb" with "Obstacle Clearance" to mean the same thing, but there are subtle differences. I suspect both arise from instruction methods and rules of thumb that have evolved and been passed along over the years - if you're Joe Pilot with no access to an obstacle database, about the only recourse you have is to use the SID and hope there's nothing inside that first mile that you might hit (-ahem- MDW and TEB).
Comment: Why do you say that ODPs are "only for use in an emergency"? I'm fairly sure they aren't, and [ATC can even assign them to you](https://aviation.stackexchange.com/q/35201/62).
Comment: You may want to structure your post in paragraphs with blank lines.
Comment: Ah...I got you. I thought you meant engine-out ODPs.