Are the different pronunciations of "species" regional differences?

Question: As far as I know, the word "species" can pronounced either as spee-sheez or as spee-seez. I understand that neither of these is incorrect: they're just two different ways to say the same thing. I also know that the second one is pretty much only used in the US. Not being a speaker myself, I'd like to know: is this a regional variation, or is it just something that depends on the speaker?
Comment: It depends on the speaker. Those who have the most occasion to use the word (biologists, especially taxonomists) may well have their own in-group pronunciation, for all I know. Attend a biology conference and hang out in the bar with a tape recorder if you want to find out the truth.
Comment: As an Australian English speaker who has served time in a university biology department I can say that 'spee-seez' is far more common. British speakers may be more inclined to use the alternative, although with many bioligical terms (notably taxonomic nomenclature) it seems to be personal preference as to which of the numerous pronounciations to use. Having said all that, I would certainly pronounce _specious_ as 'spee-shus', so there you go.
Comment: I say *spee-seez*, but I believe David Attenborough says *spee-sheez*. In fact, linguist David Crystal said in a video I watched one time that for a while he was annoyed by his child saying *skeh-jool* rather than *sheh-jool* for "schedule". For the record, I say *skeh-jool*.
Answer: The Received Pronunciation (which is the "British Standard", in a way, the one which is also exported) suggests the first one "spee-sheez". Source: Oxford English Dictionary
The US pronunciation accepts both. Source: Macmillan Dictionary
Probably the biologists would use the second one, as internationally there is more consensus on that variant. Also, it comes from ecclesiastical Latin, where the /spetʃies/ pronunciation was used.
There is more likely a professional/academical difference in pronunciation, than a geographical one, as the word is not everyday language.
Comment: The [online OED](http://www.oed.com/view/Entry/185995) (paywalled, unfortunately) lists FIVE different British pronunciations: (/ˈspiːʃɪz/, /ˈspiːʃiːz/, /ˈspiːsɪz/, /ˈspiːsiːz/, /ˈspiːʃɪiːz/); how are you determining which is RP?
Answer: It pretty much depends on the speaker, aside from the general factors you already mentioned. An older pronunciation that I don't think is used anymore was /ˈspiːʃiiːz/  ("speeshy-eez"); this stems from the same variation in syllabification that affects words like fascia (which can be pronounced /ˈfeɪʃiə/, /ˈfeɪʃə/, /ˈfæʃiə/, /ˈfæʃə/).
The pronunciation ending in /siːz/ (or in British English, sometimes /sɪz/), is a bit irregular from an etymological standpoint, although it actually doesn't have anything to do with Ecclesiastical Latin.
"-ies" was originally pronounced with two separate vowel sounds
In Latin, -ies was pronounced as two syllables. It is pronounced with two syllables in some English words, such as sanies ("sayny-eez") and paries ("pairy-eez").
However, in other words, such as rabies, scabies, and series, it is pronounced with a single vowel /iː/ (in British English, sometimes /ɪ/). This is actually an irregular correspondence between Latin and English pronunciation: the Oxford English Dictionary (OED) says that the N.E.D. (1903) listed a trisyllabic pronunciation for rabies, and the N.E.D. (1912) listed  /ˈsɪərɪiːz/ ("seery-eez") for series.
The OED still lists a trisyllabic pronunciation for caries, but all the other dictionaries I've checked give the two-syllable pronunciation.
simplification to a single vowel sound might be due to analogy?
I suspect that the pronunciation of these words has been affected by analogy, either with plural words that end in monosyllabic -ies such as cities, or simply with words where "ie" is used as a digraph to represent /iː/ (e.g. field, belief, chief). A re-analysis of rabies and scabies as plural forms seems somewhat likely since there are a number of other disease names in English that are morphologically plural (such as measles). Series also seems similar to a plural in meaning (some people, although I think mostly non-native speakers, back-form a singular serie).
That said, in "RP" British English plurals like prophecies generally are transcribed with a lax vowel (/ɪz/), so in British English pronunciations of rabies, scabies and the like with a tense vowel (/iːz/) do not actually necessarily sound like the plural forms of hypothetical singular forms "raby", "scaby".
in "-cies" words, this reanalysis affects the consonant used
In words like species, facies, superficies, it's actually pretty regular for the i to not be pronounced as a separate syllable, but we would still expect it to palatalize the preceding consonant, resulting in /ʃiːz/, due to the phenomenon of "yod coalescence" that gives us /ʃəl/ in special (as opposed to, e.g., /ri.əl~rɪ.əl/ in material). The pronunciations with unpalatalized monosyllabic "-cies" /siːz/ are irregular and would have to stem from some process of reanalysis, like the pronunciations of rabies, scabies and series that were mentioned above.
Answer: As an American, I pronounce it similar to [spee-sheez]. However, the "sh" sound in species is different from how I pronounce the "sh" in most other words. I am not sure if this is normal or not for an American. I pronounce the "sh" in species with my tongue in the normal position for "s" with the back of my tongue near where it would be for saying the y sound.
I always pronounce the normal "sh" sound with my tongue between where it would be for saying an "s" and saying a "y".
Answer: My undergrad is in Biology and I have worked in science and engineering for more than 40 years.  I travel extensively within the Americas, Europe and China.
Here's my take.
I NEVER EVER say Spee-shees and I never will.  To me, that pronunciation is fingernails on a blackboard.  Uncultured.  Seriously, I can't stand hearing it.
Spee-cees is what I say and over the course of my life I've said it A LOT.
My thought - and I have thought about it...
Someone, somewhere about ten or fifteen years ago - perhaps a broadcast newsperson of some kind - said "Spee-shees".  Some dip-sh*t person heard it and thought to themself "Say, here's a way for me to demonstrate how VERY SUPERIOR I am because Spee-Shees sounds soooo much smarter.  And that's me ... I are smart!"
Fast forward.  Now the pox is pandemic.  Every moron say Spee-shees and increasingly I hear even life-sciences professionals saying it that ugly way too.  Sad.  Yet another example of the Decline of Human Civilization.
The final insult is that David Attenborough - that's SIR David Attenborough (and the guy I wish I was) now says Spee-shees.  However, his vocalization is a slightly less horrific as he does not emphasize the repellent 'SHee' part.
Citing various dictionaries doesn't settle anything.  Dictionaries are actually pretty quick to accept common mal-pronounciations.  (Hmmm. Dictionary sales maybe???)
Do your part.
FRIENDS DON'T LET FRIENDS SAY SPEE-SHEES !!!
Comment: An 1828 dictionary says [speeshees](https://archive.org/stream/walkerspronounc00unkngoog#page/n366/mode/2up). As does an 1892 one. It's ***not*** a new pronunciation.
Comment: So we know how you _don't_ pronounce it but you don't say how you do and why.
Comment: @KillingTime well he says it's pronounced `Spee-cees`, but I'm still not convinced by this answer that it can't be regional accent that changes the pronunciation a bit. The answer names Sir David Attenborough as an example and he probably has said the word lots of times as well, just like the author of this answer claims to have done to make an authoritative argument. @george, I suggest you try to add authoritative sources to support your answer otherwise we're none the wiser as to who is correct (if one pronunciation is actually more correct). ;)


How do I repair a broken garage door opener arm bracket?

Question: The bracket that connects the push arm of our garage door opener is getting ripped off from the door (see picture below). All screws, except a bolt at the top of the bracket are detached. How can I fix this if I do it myself?
Comment: I edited your Question to remove the portion about cost, as that is off-topic here.
Answer: You might be missing the point.
Most people have only ever pushed buttons and never actually lifted a garage door, so it's easy hold the belief that a garage door is a massive 200 pound behemoth that can only possibly be opened with a burly machine.   That's absolutely untrue.
Garage doors are balanced by their springs.  Opening forces are only a few pounds.   When a power opener lifts a door, it's more like walking an old lady across the street.   At least when things are working.
Before openers, if a garage door was having problems, you'd know it immediately because you'd feel it bind, and you'd fix it early.   Now that we push buttons, the lifter just muscles the door through the defect, which of course does nothing to improve the situation.  Eventually the lifter stalls, the lifting arm breaks, or the door tears itself apart.  That last case is super bad:  Since doors amount to a spring balanced against gravity, doors contain lethal amounts of energy at all times. If a door fails, it can kill you.
So when a lifting arm breaks, that's your deity looking out for you.  Think of a weak lifting arm like a fuse that protects your wiring, or like the spillway that protects the dam.  You don't want to defeat that.
Fix your door.
Something is binding seriously in the door.  The door is trammed due to a broken lifting cable, a spring has broken, rollers are off their track or seriously damaged, etc.  Focus on that.
Comment: :) "Garage doors are balanced by their springs." As you say, till the spring breaks! Then you realize what that ugly thing is for. Especially if you have a wooden door. All good points. And a reminder that you should NEVER stand, or let anyone else stand, under the door while it is in transition, or drive in when it's not all the way up come to that.
Comment: Thanks for the response. After closer inspection, the part of the bracket that's getting ripped off was mostly help by 2 small screws and glue. I have now screwed it back in and also applying some gorilla glue. Also checking and lubricating the door to make sure it's not causing the problem. How do I check if the spring is not broken? Is there an easy way to detach the opener and manually open/close the door so I can make sure that the force needed is only small?
Answer: If cosmetics are not important to you, it would be useful to mark the bolt locations and drill through to the outside. Adding external bolts with washers to spread the load would return the bracket to near-original operating status.
If cosmetics are more important than noted above, a strong adhesive would enable the forces to be spread over a greater area than the original installation provides.
A polyurethane adhesive such as Gorilla Glue would give strong bonding, but you'd have to have some way to compress the bracket against the door while it sets.
It's difficult to determine from the photo, but you may have a wood garage door. In that case, you should remove the painted surface under the bracket to provide a better bond for the adhesive you select.
Epoxy adhesives with longer cure times, upwards of 30 minutes, will provide more strength than the much weaker five minute versions. Apply an even layer of glue and secure the bracket as firmly as possible to the door.
I would consider that a bracing timber, such as a 2x4 of sufficient length could be used to apply pressure to the bracket while the adhesive sets.
Returning the bolts to the original location, with additional adhesive in the bolt holes will also help.
Comment: Thank you. Adding additional bolts drilling through the outside worked.
Answer: I'm assuming the panel in the middle is thin so I would drill four holes in a square pattern into the bottom flat section of the bracket and fasten to the door with wood screws. I would do the same at the top flat section of the bracket. It looks like the top of the bracket is tucked under the metal brace at the top. If that brace has pulled out at all drill holes in that every four inches to fasten it back to the door.
Answer: I've had a similar repair necessary after a cable to the door spring broke. First things first, with the garage door closed disengage the opener's carriage by pulling the cord connected to it. Then by hand open and close the garage door feeling for any defects or excessive weight. If there are any anomalies, have them fixed. To fix that bracket, I used two pieces of perforated angle steel bolted through the original bracket and door panel.


Why do you call some wines by region and other wines by grapes varietal?

Question: Why do you call some wines by region and other wines by grapes varietal?
What is the reason behind?
Comment: Aside: It's not only wine. Dijon mustard is world famous, but the mustard seeds themselves are grown in Saskatchewan (Canada), then processed in Hamilton (Canada), then shipped to Dijon (France) where the product is packaged and labelled, and then finally shipped around the world (including back to Canada) for sale in grocery stores.  If that one step in Dijon weren't there, it couldn't be called "Dijon" mustard.
Answer: This is a historical thing. In Europe in the ye olden days, there was no separation between where someone grew the grapes and what the wine was called, ie Burgundy, Chianti, Bordeaux, Rioja. In most of these regions, these grapes were selected over generations of growers to work perfectly in those regions.
Later on, maybe about 100 years ago, people started naming their wines similar names to these well known regions. Champagne is the classic example and probably the first to assert it's region name (aka appellation) around the world. Calling something Champagne in California did not make it Champagne. Champagne only comes from the Champagne region of France not Napa Valley in California.
It was intrinsically known what would grow where in Europe and mostly people didn't fiddle with it. Chardonnay and Pinot Noir grew well in Burgundy and that's pretty much all they grew. Then along came the New World. Mostly after WWII, growing regions all over the world started growing grapes and didn't have the history that many of these old European regions had and they wanted to tell people what was in the bottle so the rise of grape names came into being.
In Europe they created governing bodies to protect their appellations and making laws about how and what people could grow grapes. Protecting place names became a big deal. Now it's spread to many other things like tea, cheese, tomatoes (San Marzano), etc.
In the new world, they have the freedom to pretty much grow whatever they want, how they want and wherever they can so an emphasis on cute names and grape names is emphasis and places where grapes are grown are de-emphasized (OK, there are excepts like Napa Valley and Barossa Valley) As new world areas really figure out what is best grown in their regions you will see more emphasis on regional names and less on grapes.
Answer: It depends on the wine.
If you have a quality assurance label, and a strong relation between a particular region and a kind of wine, it's better to call wines by region.
The same is true if you can get different wines in different regions from the same grape varietal.
Also, if the wine is made from different grape varietals, calling by region is an obvious choice.
Just thing about Champagne and Franciacorta: they are well-known regions for sparkling wines, the wines are from mixed grapes, and the grapes are "almost" the same.
Answer: Why do you call some wines by region and other wines by grapes varietal?
There are several factors to be taken into consideration here. First of all, let us start with the definition of what a grape varietal is.

A varietal wine is a wine made primarily from a single named grape variety, and which typically displays the name of that variety on the wine label. Examples of grape varieties commonly used in varietal wines are Cabernet Sauvignon, Chardonnay and Merlot. Wines that display the name of two or more varieties on their label, such as a Chardonnay-Viognier, are blends and not varietal wines. The term is frequently misused in place of vine variety; the term variety refers to the vine or grape while varietal refers to the wine produced by a variety.
As vintners and consumers have become aware of the characteristics of individual varieties of wine grapes, wines have also come to be identified by varietal names.
The term was popularized in the US by Maynard Amerine at the University of California, Davis after Prohibition seeking to encourage growers to choose optimal vine varieties, and later promoted by Frank Schoonmaker in the 1950s and 1960s, ultimately becoming widespread during the California wine boom of the 1970s. Varietal wines are commonly associated with New World wines in general, but there is also a long-standing tradition of varietal labelling in Germany and other German-influenced wine regions including Austria, Alsace, and the Czech Republic. - Varietal

Wine region as such generally are those regions which have had some amount of known historical wine making in their past and thus are more well know as such.
The usage of these terms seems to have several factors involved in why we call them as such.

Unlike American wines, most European wines are named for the region where their grapes grow rather than for the grape variety itself. Many of these European wines come from precisely the same grape varieties as American wines (like Chardonnay, Cabernet Sauvignon, Sauvignon Blanc, and so on), but they don't say so on the label. Instead, the labels say Burgundy, Bordeaux, Sancerre, and so on: the place where those grapes grow.
Why name a wine after a place?
Grapes, the raw material of wine, have to grow somewhere. Depending on the type of soil, the amount of sunshine and rain, and the many other characteristics that each somewhere has, the grapes will turn out differently. If the grapes are different, the wine is different. Each wine, therefore, reflects the place where its grapes grow.
In Europe, grape growers/winemakers have had centuries to figure out which grapes grow best where. They've identified most of these grape-location matchups and codified them into regulations. Therefore, the name of a place where grapes are grown in Europe automatically connotes the grape (or grapes) used to make the wine of that place. The label on the bottle usually doesn't tell you the grape (or grapes), though.
The terroir game
*Terroir is a French word that has no direct translation in English, so wine people just use the French word, for expediency. Terroir has no fixed definition; it's a concept, and people tend to define it more broadly or more narrowly to suit their own needs. The word itself is based on the French word terre, which means soil; so some people define terroir as, simply, dirt.
But terroir is really much more complex (and complicated) than just dirt. Terroir is the combination of immutable natural factors — such as topsoil, subsoil, climate (patterns of sun, rain, wind, and so on), the slope of the hill, and altitude — that a particular vineyard site has. Chances are that no two vineyards in the entire world have precisely the same combination of these factors. So terroir is considered to be the unique combination of natural factors that a particular vineyard site has.
Terroir is the guiding principle behind the European concept that wines should be named after the place they come from. The thinking goes like this: The name of the place connotes which grapes were used to make the wine of that place (because the grapes are set by regulations), and the place influences the character of those grapes in its own unique way.
Therefore, the most accurate name that a wine can have is the name of the place where its grapes grew. It's not some nefarious plot; it's just a whole different way of looking at things. Understanding Wine Names by Region


File encryption with external key

Question: I want to encrypt a few files on my computer (not FDE). To do this, I'd like to use something that requires having some external usb thing with the key on it plugged into the computer. Price is not really an issue for the usb device (ideally in the hundreds of dollars). Any recommendations for solving this problem?
Comment: openssl can do it in a variety of ways, with a key, with a password, with optional salt, to binary or to ascii base 64 etc: https://stackoverflow.com/questions/16056135/how-to-use-openssl-to-encrypt-decrypt-files
Answer: It depends on what security features you are looking for; specifically, how much you mistrust your own computer.
If you just need the decryption key to reside on a USB device, then you can put a key file on a basic USB flash drive, and use GnuPG. The key will of course make it to the main computer, because the computer will do the actual decryption work. But at least the key will not be written to a file on the computer; it will be in RAM only. This is the cheap method. It works in the case where you do not trust your computer when it is powered down; e.g. this is a laptop and you fear that it could be stolen while you are not using it.
To go one step further, you may want to consider encrypted drives like these ones. The encryption and decryption keys are known to the device only, and all encryption and decryption occur in the device, not the host computer. Some models can even be unlocked with fingerprints (a reader is embedded in the device). If the host computer is hostile (e.g. compromised with a nasty virus), it can still plunder your data when the device is inserted and unlocked, but at least you have some control on when such things may happen.
If you have really sensitive data that must never be shown to a potentially compromised computer, then the most natural solution is to buy a dedicated computer, kept offline, for this data.

File encryption with external key


Offer Price for my stock not shown on quote and a subsequent sale higher than my offer

Question: I offered 30,000  shares of stock for sale at .54  when the ask was quoted at 10,000 shares for sale at .62.  My offer never became the ask that day.  Therefore, the broker was
telling the public that the lowest price one could by this stock for was .62 at
10,000 shares.  This was a lie.  I was willing to sell mine for less than the quote.
It was not an all or none order.  To make matters worse, at the end of the trading
session, 10,000 shares were sold at a price higher than what I was asking. Is this fraud?
How does my broker get away with this?  Do I have a legitimate case?  Thanks in advance.
Comment: When the ask was .62, what was the bid? If it was .54 or higher your order should have cleared. Also - this appears to be a legal question.
Comment: Have same problem, I don't have AON. And the stock is continuously selling for higher than my limit sell price...WTF?? Is this HFT cutting in line? I'm ordering thru scottrade online....this has happened many times. Crap shoot if they sell.
Answer: Many exchanges trade the same securities.  An order may be posted to a secondary exchange, but if the National Best Bid and Offer data provider malfunctions, only those with data feeds from that exchange will see it.
Only the data provider for the primary exchange where a stock is listed provides the NBBO.
Missing orders are very common with the NBBO data providers.  NASDAQ's order consolidator has had many failures over the past few years, and the data provider's top executive has recently resigned.
Brokers have no control over this system.  A broker may be alerted to a malfunction by an accountholder, but a broker may only inform the relevant exchange and the relevant data provider.
Answer: It depends on the way you have directed the order and the execution agreement you have signed with your broker. In case of DMA (direct market access) you would direct your order to the specific exchange - and that exchange would post your offer, assuming you did not tag it as hidden. However, if you just gave your order to the broker (be it via telephone, email or even online), they may not have to display your order to the market or chose which exchange to sell it on. It will also depend where the stock is listed. For most US listed and OTC stocks, regulation NMS applies where your order should have been executed against if it went to the exchanges. Check your account opening docs and agreements, particulary the execution agreement. In there it will tell you how your order should be treated. In case where the broker stipulates that you have DMA or that they will direct your order to Lit markets (public exchanges and not market making firms and dark-pools) then you may have a case - you would need to request information to whcih exchange your broker sent the order to. In case that you gave them discretion on routing of your order - read the fine print. The answer lies there.
Regarding NBBO missing you quote as quantycuenta suggested above is also a possibility, however Reg NMS should take care of this. Do you have stock and date & time of your order?
Answer: There are a few things you are missing here. These appear to be penny stocks or subpenny stocks. Buying these are easy.... selling is a total different ball game. Buying commissions are low and selling commissions are outrageous. Another thing you are missing in this order is... some trading platform may assume the "AON" sale. That is All Or None. There was an offer of 10k shares @ .63. The buyer only wanted 10k what was the broker to do with the other 20k? Did you inform the broker that partial sales where acceptable? You may want to contact your broker and explain this to them. The ALL OR NONE order has made plenty of investor a little unhappy, which seems to be your new learning experience for the day. Sorry, school of hard knocks is not always fun.
Comment: OP states that the offer was explicitly not all-or-none.


Surveying fossil fuel deposits from the air

Question: On Earth in 2017, finding oil or coal deposits is a tall order. However, consider a science fiction scenario where we find a habitable planet that hasn't hosted an intelligent species in at least a hundred million years, so has fossil fuel deposits in easily accessible locations. Is there a way to find them from the air, or even better from orbit, using today's sensor technology?
Comment: I have the very urgent hope that a spacefaring civilization has found better fuel sources than burning dead dinosaurs... But it might be a valuable option if you want a (controlled) greenhouse effect.
Comment: @Burki The latter is actually the case - some of the discovered planets are uncomfortably cold, so adding carbon dioxide to the atmosphere would be helpful.
Answer: Yes.
Early exploration for oil tended to focus on two things - the presence of  oil seeps at the surface, where oil migrating from source rocks was reaching the surface, and topographical highs, which often correspond to geological uplifts that form hydrocarbon traps.
Both of these features should be detectable from orbit. We look for evidence of surface hydrocarbons which are very unstable in an oxygen atmosphere, and therefore must be recent - and topography that indicates suitable underlying geology. This would give a set of candidate drilling areas. The classic Earth location for this would be the Zagros mountains in Iran.
This would only find the most obvious locations, and you'd still drill a lot of dry wells, but it would give you a great start.
Comment: Actually it would be easier to detect earthquakes and use the pattern of vibrations around the planet to image the interior - https://en.wikipedia.org/wiki/Seismic_tomography - but that's a bit too far for current technology.
Comment: With a couple of satellites, a neutrino emiiter and a neutrino detector carefully aimed at each other, you could make a sort of CT-scan of the planet at variable deeps, thus having a quite accurate density map of the different layers of the planet (atmosphere, oceans and crust). You can then combine this information with the rest of sources to locate the really big oit deposits and save yourself from drilling dry or superficial but small deposits.
Comment: And you have to wait for earthquakes and fill either the planet's surface with sensors or its LEO orbit with extremely advanced laser meters. I think the only thing preventing us to use the neutrino-based meters is the difficulty of putting them in orbit (a lot of weight, they must be assembled by pieces, etc). I suppose that in the OP's scenario this is a minor inconvenience.
Comment: @Rekesoft Why wait for an earthquake? Just chuck a lump of rock down from orbit and it will generate some quite satisfactory seismic waves when it hits the ground.
Comment: I don't know enough about geology to know if the waves generated by a collision from above would generate the same kind of waves than friction from tectonic plates, though I suspect not. But if you don't mind destroying the planet while you seek (and I think you should mind) you can just hit the identified drilling zones and see what pops out of the explosion.
Answer: It could be done using XIX century technology. Gravity change, magnetic field change and electrical resistance is the "advanced" technics.
You could use Eoetvoes's torsion balance.
If you can have specialised station on orbit you just equip it radars and map the planet.
Anyway, you would search for the fuel the same way you search for it on earth. How do you think they find oil in Mexican Bay? Looked for oil ring on the surface?
Answer: Remote sensing as it is called has been in use for many decades, even simple stereoscopic photographs taken from the air or satelites can be of use to a Geologist looking for oil. These enable them to look at the ground surface and look for evidence of geological features such as salt diapers, and faulting that are known oil and gas traps.
Magnetic and Gravity surveys also give clues to the presence of oil in the strata below the Earth.
Radar can be also used from space to map the Earths surface and map it.
This chapter in Google books from Remote Sensing: Principles and Applications, Third Edition by Floyd F. Sabins might be of interest to read.


How to clean a drone?

Question: I was just flying my drone when I crashed in some tall grass and there are now a bunch of grass bits all over the drone. How can I clean the drone without damaging it?
Answer: I have found that the simplest and probably one of the safest ways is to use a compressor (alternatively a compressed air can will probably work), to lightly blow away the dirt. This works especially well if you just want to get rid of grass straws or similar.
If you want to more thoroughly clean something Joshua Bardwell has a video on how to clean a motor, and if you want to clean a PCB or other electronics, alcohol > 90% and some kind of brush or cotton swab works. And finally, if it's the frame you want clean, soap and hot water works.
Answer: I would personally recommend using isopropyl alcohol or mostly any other type of alcohol and using it with a cloth to gently clean the drones shell and propellers off any marks/stains. This shouldn't damage the drone. As well as this, a microfibre cloth could also work well.
Comment: Some electronic components have waterproofing or other protective coating on them that the alcohol will wash away. You can reapply the coating later or just fly without it if you don't expect moisture on the electronics, just keep in mind that careless cleaning may cause more problems than doing nothing :)
Answer: I've got a paintbrush in my flight kit which I use for removing chunks of mud/grass from my quads so I can keep flying on the day.
If they get really dirty, I use a toothbrush dipped in alcohol once I get home.
If they are really bad, I pull them apart and go over each part with the toothbrush and alcohol.
Answer: I've had success cleaning grass from drones using a damp cloth (just water.) You shouldn't need chemicals to get grass splatters off if they are fresh, but if you do use them then try it on an inconspicuous part first in case it does cause discolouration.
Make sure the battery is removed to prevent damage should any electronics get too wet, and let the aircraft dry thoroughly before powering back up.
Answer: For non-electronic parts (frame, camera case etc.) I'm using just those "cotton ear cleaning sticks" and plain water. If you just wet the dirty spot, wait a minute until the water softens the dirt and then you can just easily wipe it off.
And for electronics I would use same technique but use alcohol like other answers recommend.

How to clean a drone?


How to know which spells my mage can cast?

Question: I have just started my first run of Legends of Grimrock. I have in my party an insectoid mage with 3 points in Ice Magic. The tooltip shows me that, at level 3, it should have a spell, marked with 3 question marks (???). How can I know which spell it is and how to cast it?
Answer: There's a few things at play here.
First of all, you need to discover the rune combination for a certain spell to cast it. In-game, you do this by finding scrolls, but you can also discover combinations via experimentation (or searching the Internet). For instance, I discovered the rune for Fireburst through experimentation before I ever found the scroll. Likewise, I experimented and found that the first earth spell just uses a single earth symbol. I imagine ice and wind do the same thing, but haven't had the skill to try them yet.

However, even if you know the correct rune combination for a spell, you still need to have a high enough skill level in the relevant magic type to cast the spell. That's where the ??? comes in when you're looking at your magic skill levels. Once you've successfully entered the correct rune combo for that spell, the ??? on your skill description will change to the name of the spell.

Regardless of how or when you discover the rune combo for a spell, you can still only cast spells that your skill is high enough to have "unlocked", and your skill text won't tell you what spell it lets you cast until after you've already cast it. It's a bit frustrating, since I took earth magic hoping it would have some a low level healing spell, as many games seem to tie "healing" to "earth". Instead, I discovered through play that the first Earth spells is actually "poison cloud".
So, via in-game means, you'll just have to discover it as you go. If you want to be able to plan ahead where to put your magic points so you can get to certain spells sooner (and for that matter, even know what spells exist), you'll have to look to an external source such as this one.

For reference, here are the available spells:
Air Magic

Level 4 - Spell Shock - Air
Level 9 - Enchanted Shock Arrow - Air, Life, Physicality, Death
Level 14 - Lightning Bolt - Air, Spirituality
Level 19 - Invisibility - Air, Balance, Death
Level 22 - Shock Shield - Air, Balance

Earth Magic

Level 3 - Poison Cloud - Earth
Level 7 - Poison Bolt - Earth, Air
Level 11 - Enchanted Poison Arrow - Earth, Life, Physicality, Death
Level 13 - Poison Shield - Earth, Balance

Fire Magic

Level 2 - Fire Burst - Fire
Level 7 - Enchanted Fire Arrow - Fire, Life, Physicality, Death
Level 13 - Fire Ball - Fire, Physicality, Air
Level 16 - Fire Shield - Fire, Balance

Ice Magic

Level 3 - Ice Shards - Ice, Earth
Level 7 - Enchanted Ice Arrow - Ice, Life, Physicality, Death
Level 13 - Frostbolt - Ice, Air
Level 19 - Frost Shield - Ice, Balance

Spellcraft

Level 5 - Light - Balance, Light
Level 5 - Darkness - Balance, Darkness
Comment: @yx. No, but there are a lot of options for healing. Herbs for healing potions are fairly plentiful. The blue glowing crystals that are on every dungeon level and auto-save your game will fully heal and restore you (they even bring back the dead!) and can be used repeatedly, with a short cooldown. And then there's always the option of finding a safe spot and resting.
Comment: http://tinyurl.com/GrimRockSpells Another Source
Comment: so there are no heal spells :(
Comment: I'm liking the game, but yes, the spellcasting system is really lacking imho (besides, having more than one caster in the group can really mess you up)
Comment: Is there an ingame list of the learned/discovered spells and how you can cast it?
kept old scrolls and made my own notes so far...


SSL "unable to get local issuer certificate" : "full chain" vs "root"?

Question: Summary
In summary I have some certificate related files and some certificate related instructions but I'm not sure which files are which !
Background
I've just installed a certificate from Lets Encrypt by using acme.sh
The output from that process looks like this :
[Sat Aug 18 02:50:24 UTC 2018] Your cert is in  /home/ubuntu/.acme.sh/www.foobar.xyz/www.foobar.xyz.cer
[Sat Aug 18 02:50:24 UTC 2018] Your cert key is in  /home/ubuntu/.acme.sh/www.foobar.xyz/www.foobar.xyz.key
[Sat Aug 18 02:50:24 UTC 2018] The intermediate CA cert is in  /home/ubuntu/.acme.sh/www.foobar.xyz/ca.cer
[Sat Aug 18 02:50:24 UTC 2018] And the full chain certs is there:  /home/ubuntu/.acme.sh/www.foobar.xyz/fullchain.cer

So after configuring Nginx this is all works when requests are made to https://www.foobar.xyz through a conventional browser.
Problem
But when I make the same request via Curl I get :
curl: (60) SSL certificate problem: unable to get local issuer certificate

So it seems there are two ways to fix this.

tell Curl to ignore the issue or provide curl with a client side list of certificating authorities.
alter the certificate on the server

Question
I want the second option, the change on the server, and this page gives instructions on how to do it specifically ...

2) If you received the intermediate certificates in one bundle file or
  downloaded the certificate files in your account with us, you can use
  this command:
cat example_com.crt bundle.crt >> ssl-bundle.crt
Place the concatenated file into the directory with SSL certificates
  on your Nginx server.

The problem I have is that I'm not sure which of the files produced by running acme.sh correspond to the example_com.crt and the bundle.crt ?
I think bundle.crt corresponds to www.foobar.xyz.cer ?
But I'm not sure what example_com.crt corresponds to ?
Comment: Aside: the names of files are irrelevant, only the content counts. You should name the files in such a way that they are clear to you what they contain.
Answer: The bundle is fullchain.cer. It contains ca.cer and www.foobar.xyz.cer.


Need to install wood framing in a pipe filled wall to be able to hang shelving

Question: I've got this wall, from which I've ripped off the drywall. The wall is 5' wide, 9' high. There's 4 flimsy metal studs and I'd like to install a few big sheets of plywood over those so I can put up 6 five foot long shelves.
I would like to join 3 cut up pieces of 2x4 to the big beam on top to block out a little past the metal studs, and then attach some pieces of 2x4 to the floor. After that, attach a long sheet of plywood to those 2 blocked out pieces.
My question is, would that be a strong enough way to hold down an 8' sheet of plywood, only securing it by 2 ends?
Here's a picture of the situation:
Comment: ...and exactly **why** are you not fastening to the studs?
Comment: Is there a reason you don't want stand-alone shelving, which wouldn't get any strength from the wall?
Comment: When you say "securing it by 2 ends" does that mean that you only want 2 points of contact?  I've seen this done with 4 points of contact, 2 on each end.  Please clarify.
Answer: So, you've got lots of options, some of which no "real" contractor would ever do, but are perfectly fine.
If you use long drywall screws you can screw your wood blocking to the metal studs, just like you would if the studs were wood.  Sharp screws will penetrate the metal studs.  This is not optimal because your skill at doing this non-standard solution could result in shelf failure later, though it's probably what I would do.
You could do as one of commenters suggested and put stand-alone shelving agains the wall and attach it with brackets to the new drywall or directly into the metal studs- perfectly fine - very DIYish.  Use drywall anchors.
You could screw shelves directly into the metal studs - they are studs - they hold weight - no problem.  This is also something I would probably do.  Use drywall anchors.
You could use 1/2 or 3/4 plywood on the wall instead of drywall.  Kind of odd, but it will provide excellent holding capacity to attach shelving. (I have a plywood wall in my mudroom - shelving bolted right on.
You could attach vertical wood 2x4x on top of the drywall floor to ceiling, attached to the studs (essentially a new set of exposed studs).  Then attach your shelving to that.
Basically, your goal is to get something that isn't going to easily rip away from the wall...and a nearly infinite variety of screws, wood and brackets will satisfy this.
Comment: This is along the lines of what I was going to give as an answer, but I would add blocking from one set of metal studs to the other since the pipes literally cut the metal studs in half and therefore will not let the wood studs make a complete path either. That would give enough strength to any wall if you attached the shelf standards to the wood studs. Lay on them if you like, they will hold, at least to the wall. The plywood you refer to would give you complete flexibility in fastening. Depending on the shelf system the OP is doing, one row of blocks at the top, will hold a hanging shelf.
Answer: The shear strength of a few dozen appropriate screws through 1/2" or better plywood into the steel framing, plus the load distribution of its own rigidity, will give you more than enough strength to carry several hundred pounds on your shelving. Some caveats:

Be sure that the top plate is securely anchored to the framing above.
Be sure that your plywood spans onto the top plate and fastens to it, as well as to the studs and any wood blocking you have in place. Not doing that puts a large load on the joint at the top of the studs. That could end badly.
Be sure that the plywood is fastened snugly against the framing. Gaps weaken the system by creating a torsional load rather than entirely shear loading.

Note that the fastening power of any screw is  largely dependent on its diameter--a 50% increase in diameter yields substantially more thread circumference.


How long is Key lifetime of AES-GCM key?

Question: As I know the AES-GCM used a nonce and if the two message has the same nonce then the secret key can be retrieved.
If two computers use the AES-GCM to encrypt exchange messages, then what is the key's lifetime of AES-GCM?
Answer:
As I know the AES-GCM used a nonce and if the two message has the same nonce then the secret key can be retrieved.

Yes and no. The authentication key can be determined if the same nonce is used for more than 1 unique message, but the encryption key cannot. This means that an attacker could forge messages that would be authentic, but they would not be able to decrypt the data. Since GCM uses CTR, an attacker will also easily determine the XOR of the plaintexts encrypted with the same nonce.
At this point you can basically consider all other messages encrypted with that key as having been encrypted in CTR mode, as the authentication key is leaked and you longer have any way of telling which messages are authentic. All other messages are still confidential though, so it's not nearly as bad as leaking the encryption key.

If two computers use the AES-GCM to encrypt exchange messages, then what is the key's lifetime of AES-GCM

(I assume you're asking how long the lifetime should be)
AES-GCM has a message size limit of a little under 64GiB, but the maximum number of messages per key depends on the nonce construction used.
Deterministic construction
The deterministic construction consists of the concatenation of a fixed field and an invocation field (i.e. a counter). The fixed field is required to be unique per device, and the invocation field is required to be unique for each plaintext that is encrypted on a device.
Random construction
The random construction uses a CSPRNG to generate a nonce of predetermined length between 96 and 264 - 1 bits.
Maximum message counts
If using a random construction (which is required to have at least 12 bytes of entropy), the maximum number of messages is 232.
If using a deterministic construction that's not equal to exactly 12 bytes, the maximum number of messages is 232, or 2S, whichever is smaller (where S is the bit length of the counter used in the construction).
For a deterministic construction for a 12 byte nonce, the maximum number of messages is 2S (where again S is the counter size in bits).
Of course, it's best to re-key well before these limits are reached.
Answer: The answer is in the NIST 800-38D, you can access it from ACM now.

The total number of invocations of the authenticated encryption function shall not exceed 2^32, including all IV lengths and all instances of the authenticated encryption function with
  the given key.

Note: not the secret key the message can be retrieved.
Comment: Not strictly true, I have an application using a 2^64 limit by using the deterministic construction with a 32 bit fixed field and 64 bit invocation field. In the extreme case, you could have a fixed field of 1 bit, and an invocation field of 95 bits for 2^95 messages.


Opinion based question

Question: This question is entirely about opinion and cannot have any one definite answer.  Why has it not been closed?
Subjects to discuss while on break with older colleagues
Comment: "Why has it not been closed?" - because not enough people have voted to close it.
Answer: To answer your question plainly: because it hasn't gotten enough votes to be closed as such. Mods don't really sort through questions looking to close them; that's the community's job as a whole.
Comment: This is clearly the correct answer to the question as asked. I don't know why it was downvoted.
Answer: It is answerable in the general case where a strategy is given rather than specific examples of topics.  The advice given in the highest upvoted, accepted answer doesn't try to tell the OP what to say, merely that they should just simply talk about what interests them.
Answers that try to give the OP a list of topics are unhelpful and, as you say, entirely opinion based.  However, there is a reasonable recommended strategy that the accepted answer addresses.
Comment: Members of the community use their own discretion with regards to upvoting, downvoting or closing questions.  Sometimes I agree with the outcome, sometimes I don't.  But it's the _community_ that decides how to treat a particular question.  I have no doubt there are inconsistencies, but that's how a community-based moderation system works.
Comment: You always have the option of coming to meta with your question and explaining why it should be reopened.  A decent proportion of closed questions do get reopened, they sometimes only need minor adjustment to go from what the community deems unanswerable to answerable.  I suggest if you feel strongly that your question warrants reopening, that you post here in meta.
Comment: "Moderators should be able to police blatantly off-topic content, but nothing else"  Just to clarify, moderators don't close questions, users with the abilty to vote to close do.  Only on very rare occasions to the mods unilaterally close questions.
Comment: I expanded on my comments.  It seems to me that Workplace moderation policies are based upon whims and not any knowable criteria.
Comment: I appreciate your responses.  I will consider getting my question reviewed here for re-opening.  I was aware that users can vote to close.
Comment: What is a general case?  Can you expand on that term and it's meaning in this context?  Can you point to a meta post or something that expands on that? I asked a question on workplace some time ago, which was clearly about the definition of a term. I told a story to expand on the history behind why I was asking.  My question was closed as opinion based.  This question also contains a story and a lot of random commentary on personality traits.
Comment: @mrsuttonsaiditfirst As in the answer, the general case is when you give a strategy (in this case, talk about what interests you), as opposed to the specific case where you give examples of what to talk about.
Comment: @mrsuttonsaiditfirst I have edited the answer.
Comment: This apparent attempt at a policy is not being followed: http://meta.workplace.stackexchange.com/questions/2693/custom-off-topic-close-reasons-change/2696#2696
Comment: And that is why I don't post here anymore.  The "community" is ultimately a hierarchy of bullies who enjoy marking questions as "closed" or "off-topic" or "Real questions have answers."  My question did have an answer and I was coming to the community to validate my intuitions about it.  Good people are avoiding it for that very reason. Moderators should be able to police blatantly off-topic content, but nothing else.

Opinion based question


Will an eMac boot without a PRAM battery installed?

Question: eMacs have a 3.6V PRAM battery and some sources indicate that when the voltage starts to drop that they may have trouble booting. Will an eMac work without a battery?
Answer: No. I measured the voltage across the power pins before and after installing a new battery and observed a change from 0V to 3.6V. The three pins for the power switch are 3.6V, ground and ground, with this potential difference coming from the PRAM battery. Without a battery installed (or with a battery that's severely depleted) closing the switch does nothing and the machine will not power on or show any signs of life.
Answer: Yes, I pulled both dead pram batteries our of my emacs, they boot fine, just don't keep settings when unplugged.
Comment: Wonder if there's differences between models then. Will have to get the model code for mine
Answer: I just started an eMac that has not run for 2 years.  Even at that time the battery was kaput; it couldn't keep time and you had to set the time.
It started just fine for me, several times over and over.
However when I plugged in this eMac, the power strip happened to be in a location that is very dark.  I could see a minor arc flash as the plug made contact.  Something is powered up 24x7, and it has a capacitor!


KVM - How to remove virtual video card, but keep the SPICE Server?

Question: I am passing through a physical GPU to my virtual machine, and using the SPICE Server/Display Spice for sound. However, the virtual GPU (Cirrus/QXL/VGA/Virtio/VMVGA/Xen) is causing some sort of conflict with the real GPU, as when it is enabled, the monitor which I am using to display the output from the real GPU displays none or incorrect output.
I have tried this with all the possible virtual video cards, and had the most success with VMVGA, which allowed me to go as far as displaying the GRUB menu. There was no output after actually booting up the OS (Debian Testing). With others, not even the GRUB was displayed.
If I remove both the SPICE Server and the video card, the real GPU works well with the correct output, drivers and everything. But as stated, I need the SPICE Server. I tried to remove only the virtual video card, both through virtmanager and XML modification, but it always returns.
Is there any way to remove the card, but keep SPICE?
Is there any other way to make the virtual sound device work (it doesn't seem to work without SPICE, specifically it doesn't play the sound on the host)?
If the card cannot be removed, can it be disabled, so the virtual machine/guest OS won't touch it at all?
Any other solutions to this problem?
Answer: SPICE is the video, it's a protocol that includes video, sound and control channels for remote access to the qemu process controlling the guest. You can't decouple the sound from the server. If you need to use a passed through video card, you might as well pass the sound card through too.


What kind of paint and varnish can be used with ABS?

Question: I know that acrylic paint, the same kind that is used to paint miniature figurines, works best for PLA. Does it works on ABS pieces as well? Can I also use the same kind of varnish that is used for miniatures on my painted ABS prints? If not, what kind of paint and varnish works on ABS prints?
Answer: ABS is more soluble in solvents than is PLA.  Acetone will dissolve it, which can be a benefit because it allows vapor smoothing, but can be a problem with some paints which have solvents other than water.  Try out any new paint on a scrap piece.  Apply a thick dot of the paint, let it sit for a couple of minutes, and then wipe it off.  If there is a change in the shape or color where the dot had been, the paint may be dissolving the ABS.
Acrylic has a water base and does not attack ABS.
A paint that attacks ABS may be fine, but there may be some color bleeding of the ABS color into the paint.  A translucent (or clear) ABS would minimize the problem, since does not contain any pigment.
Spray painting may work better because the paint is undisturbed once applied.  Brushing on paint will mix the dissolved layer with the unaltered paint.


what is the best way to do that name?get=

Question: ok assume i have php page
has this name name.php?get= and has get varible named get
ok
how i can make it appear like that name?get=
Comment: I'm not sure what exactly you're asking here. Do you want to create a link to 'name?get=$get' or do you want to get the value of 'get' in the query string?
Comment: Which web server are you using?
Answer: If you are using apache, mod_rewrite is one way to go. There is a whole bunch of mod_rewrite tricks here.
Answer: I think you're wanting to re-write the URL client-side, which would include mod_rewrite.
In the route of your website, create a file called .htaccess and place the following code in it:
RewriteEngine on
RewriteRule ^name?get=(.*) /name.php?get=$1

Now when you type http://www.example.com/name?get=something, it will actually map to http://www.example.com/name.php?get=something transparently for you.
Answer: I'd seriously reconsider before using (or overusing) mod_rewrite.
In almost all of my projects I use a simple mod rewrite in the .htaccess:
RewriteEngine On

RewriteCond %{SCRIPT_FILENAME} !-d
RewriteCond %{SCRIPT_FILENAME} !-f

RewriteRule ^.*$ ./

AddHandler php5-script .php

This tells the server to forward all pages to / (index.php) unless a file otherwise exists.
In the root directory I have a folder called "views" with all of the pages that I use. E.g. the file used for /home would actually be /views/home.php. However, in the index.php I have a script that parses the user's url, checks for the file, and includes that.
$page = substr($_SERVER['REQUEST_URI'], 1);
if(!$page) :
    header("Location: /home");
if(file_exists("views/$page.php")) :
    include "views/$page.php";
else :
    include "views/$page.php";
endif;

This creates a variable called $page that stores the value of everything in the URL after the domain name. I use a substr() function on the Request URI to get rid of the trailing forward slash (/) on the URL.
If the variable is empty, for example if the user is simply at http://example.com or http://example.com/ then it forwards them to /home, where the script then checks for the home.php file inside of the views folder. If that file exists, it includes it, and displays it to the user.
Else, the script will simply include the 404 page telling the user that the file doesn't exist.
Hopefully this helps you, and if you need any further explanation I'd be happy to help!
Answer: As far as i could understand your question, you can not strip the file extension because otherwise it will not run. In other words, you can not change:
name.php?get=

into
name?get=

But if you mean to create links with query string values that you can put them in hyperlinks in this way:
Click here !!

Comment: Depending on the web server, you can absolutely 'strip the file extension', e.g. with mod_rewrite on Apache.
Comment: @njk You can, but it's ugly and not the ideal way of doing things. URLs then would become name?get=whatever and not name/?get=whatever.

To me, the latter seems much nicer.
Comment: Anything is possible with mod_rewrite, and in fact "name?get=" is the requirement in the above question...
Answer: If you're looking to create links using a variable '$get', then you can create the link like this:
Link
Or if you want to get the value of the query string variable, you can use this:
$get = $_GET['get']


2003 Ford Expedition xlt 4WD. Vents changing positions

Question: When I drive in highway the vents go from the face position to defrost vents and to floor while the selection is on face. Anyone know what this could be from or solutions for it to get fixed
Answer: The blend door actuator is vacuum-controlled so the first thing you want to do is check for vacuum leaks.
Under the hood, and between the firewall and the battery, there is a one-way check valve with a T-connector that connects three vacuum hoses.  I would check the connections here for damage and leaks. I would also follow the hoses to further check for damage. The one going to the left attaches to a vacuum reservoir can on the back of the battery tray. Check this, too.
There's another hose behind the battery tray that is just lying there connected to nothing and can be traced downward under the ac lines. This is part of the hvac vacuum control and should also be inspected.
Any vacuum lines inside the cab dash will need to be checked next. If it comes to it, you can rent or buy a vacuum tester from the auto parts store to check for loss of vacuum to confirm you're either holding or losing vacuum.
Another possibility is a defective vacuum control solenoid. It may be possible that the blend door actuator has a hole in the diaphragm, too, which would require replacement.
Hope that helps. Good luck.


How to install ubuntu 12.10 on windows Virtual PC?

Question: I'm having trouble installing ubuntu 12.10 on a Virtual PC. I've got 12.04 to boot and mounted it onto the virtual disk but there seems to be a problem with networking. Everytime I create the virtual disk for 12.10 it says its not large enough even though it is way over the required disk space. The disk is a fixed size not expanding.
Comment: Please tell us why you suspect "a problem with networking".
Answer: Windows Virtual PC exists solely to emulate other (usually earlier) versions of Windows.
To run Ubuntu 12.10 on a virtual machine you should download VMware Player:
http://www.vmware.com/products/player/overview.html
Or Virtual Box:
https://www.virtualbox.org/


What reasons might a programmer have for wanting hyperthreading turned off?

Question: My company just bought new computers to replace old 2GB Windows XP machines. Someone on my team noticed that they came with hyperthreading disabled, and told everyone to reboot and turn it on. Is there a benefit to programming on a machine with hyperthreading disabled?
Comment: What model of Intel CPUs are you using,e.g. Core i5 or i7?
Comment: @JBK Good question, I don't know, I don't have one of those machines myself.
Comment: On an old Pentium 4 notebook, to reduce heat and fan noise, and maybe make the battery last a few more minutes. Not an answer because it *should* be an ancient history thing, and shouldn't apply in your case.
Comment: In the Lucasarts game Grim Fandango the sound engine ran into a race condition when running with hyperthreading.
Answer: Yes I've worked on an app which performed better when running on a machine with HT disabled.
What happened was, the original code would create twice as many as threads when run on a hyperthreaded machine (which you'd assume is sort of the whole point of HT).  However, the throughput of those threads was very sensitive to the amount of cache available to the thread.  With twice as many threads fighting for a fixed amount of cache, cache available per thread was too low and thrashing occurred: there'd be loads more cache misses, loads more main-memory accesses, and performance took a substantial hit compared with running with less threads and more cache per thread (which is what you got if you ran the app on a machine with HT disabled).
The ultimate fix was to have the app check the HW platform better and take cache sizes and the amount of cache considered needed per thread into account when deciding how many threads to create.  In any case the issue quickly disappeared with the subsequent generation of CPUs, which doubled cache size (and we actually started seeing a modest benefit from HT then).  However, the whole episode left a long and lasting legacy of recommending HT always be disabled on any platform our SW ran on, and knee-jerk "that machine hasn't got HT enabled has it?" responses to any performance problem.  (I think the fundamental problem is most non-geeks simply don't understand what HT actually is.)
Answer: I don't know the technical details, but apparently if an app (or the OS) is not optimized for hyper-threading, hyper-threading can actually decrease performance.
Even Intel recommends turning it off in this case:

The following desktop operating
  systems are not recommended for use
  with Hyper-Threading Technology. If
  you are using one of the following
  desktop operating systems, it is
  advised that you should disable
  Hyper-Threading Technology in the
  system BIOS Setup program: [...]

(Source: http://www.intel.com/support/processors/sb/CS-017343.htm )
So maybe the manufacturer (or the supplier) wanted to be careful.
Comment: It would be interesting if they were concerned about the performance of games played at work.
Comment: @Steve314: That was certainly the case back with Windows2000 (and disabling HT was definitely a good idea if you were running that) but Windows XP was supposed to be HT aware (see e.g http://download.microsoft.com/download/5/7/7/577a5684-8a83-43ae-9272-ff260a9c20e2/Hyper-thread_Windows.doc ) and not fall into such a trap.  I assume similar logic got built into Linux from some version of the kernel.
Comment: It's also known to make some games run slower than when hyperthreading is deactivated.
Comment: On a multi-core system, two threads might be allocated to two hyperthreads on the same core, leaving all the other cores idle and giving much less performance than putting each thread on a different core. Until operating systems become aware of the difference between a different core and different hyperthreads on the same core...
Answer: More than likely, the OEM was just being conservative.  OEM's often ship with advanced featuers disabled (like HT, No-Execute bit, vt, etc..) turned off.  The reason is that some rare circumstance might make those settings fail, and people that actually want the features can just as easily turn them on.
Also, some rare bugs in OS's have lead to potential security issues when some features are enabled.  virtualization technology, for instance, once had such a problem.  So, it's just the vendor being conservative.
Hyperthreading is generally useful for interactive desktops, like programming machines.  Although, some people might want to turn it off if your apps are going to run on servers without HT.  Just to reduce potential hardware differences.
Comment: This is almost always the case for machines that come with HT turned off.  Maximum compatibility and saving the vendor from a flood of weird support calls.
Answer: Hyperthreading doesn't add new cores to the CPU. You still have one arithmetic/logic unit, one floating point unit (...) per core. So if you have multiple threads/processes that do very different things, HTT can improve performance. But if you have multiple threads doing more or less the same things (not uncommon in number crunching applications), performance can actually suffer badly from HTT.
Answer: Maybe cache-coherence issues in massively multithreaded code?  If you have discrete CPU caches, it's theoretically possible for two threads to have the same data cached and modify it at the same time with different values.  If you have a unified cache at some point between the CPUs and main memory (either L2 or L3), then there's probably some mechanism in place that will prevent this, but on lower-end CPUs with smaller caches, maybe not.
Alternately, it may be possible that enabling hyperthreading on chips that don't support it will throw a code during POST, so the BIOS supplier just leaves it off because they don't know what kind of CPU the system will have.
Comment: My guess - there's a mechanism in place to resolve this coherence issue, but it may have a significant performance penalty. IIRC, a particular page of memory cannot be freely loaded into just any cache page - there's typically a this-address-maps-to-one-of-these-few-pages mechanism. Maybe it's possible for two threads to fight over a few cache pages, leaving the rest unused? (maybe even with multi-core, though presumably with less risk).
Answer: One reason not to turn off hyperthreading on a developer machine is that it may hide some subtle multi-threading bugs. But this only really applies on a single-core single-processor machine. Multi-core will expose, if anything, more multi-threading bugs during testing.
OTOH, I doubt you'll see a single-core processor with hyperthreading disabled by default. My vote is on Sleskes answer.
Answer: A lot of old software was written on single core machines, and may have had bugs in it when running on a multicore machine. Probably the instruction was really meant to say "This doesn't work in multicore machines", it's just that for a long time hyperthreading was the only likely multi-core machine you'd see in common use.


transfering compositing nodes with render layer nodes

Question: I have two projects. In one I have a lot of compositing nodes including a lot of render layer nodes. I have found a way to append nodes but it does not work with render layer nodes. Is there a way to append compositing nodes including the render layer ones? It would take me ages to copy that and yet it would not be the same.
Thank you very much.
Answer: Append a Scene
Compositor nodes belong to the Scene settings.
You just have to Append a Scene from a blendile containing the compositor setup you want. Go under -> File -> Append, pick the file and look under the Scene folder.

Then go to the scene selector, open the compositor in the appended one and copy past the nodes in yours.

Remember to update the render layer input scene in the copied compositor node setup.
Comment: @user115148 does this help you?
Comment: Thank you very much for your answer. I did append files from the scene folder,. There are 3 files:  _mainScene, dustParticules, and volumeLight. I did try to append just _mainScene and since it did nothing I also tried to append all of those. (The blender just freezes for few seconds and then nothing happens) But nothing happened. The compositor nodes did not change at all. Do you know what could be the issue? Thank you.
Comment: Once you append a scene. you should find the scene in the scene in the scene selector. I've added some lines to the answer.
Comment: Thank you. I did copy the node, then changed the scene to the one I want the nodes to be in. But when I wanted to render it, it rendered the scene from the second project. Even though I had the scene I wanted to render selected.
Comment: We are almost there. In the compositor you have to update the Render Layer Scene to use. Also, after copying the nodes, remember to delete the scene you appended, or your file will increase it's size.


keeping cats out of open loft

Question: I have rented an apartment, that has open area above the kitchen cabinets where the ducts and electric items are. Any advice what to put up to prevent cats from jumping from counters to top of duct work, then getting into trouble
Comment: Can you include a photo? I'm having trouble picturing the setup.
Comment: There is nothing to stop a cat from going where you don't want him to go...You can just pretend you don't care if he goes to that area, and he won't go. Cats, by definition, only invade areas you don't want them to invade XD
Comment: @MarioGarcia: So true... Actually the best way to force cat not to do something is to reliably pretend you want him to do that :)
Comment: In ancient times cats were worshipped as gods; they have not forgotten this. Terry Pratchett
Read more at: https://www.brainyquote.com/quotes/terry_pratchett_384583
Answer: There's really no point in jeopardizing your pet's well-being or health trying to find stuff to antagonize or repel it.
The answer is in your question. You must change the "open" areas into "closed" or "obstructed access" ones. Block the access to the areas you want undisturbed and unexplored.
The materials are many and varied due to availability and cost of your choice. Paper card stock or cardboard is inexpensive and easily made and positioned. Plastic or wood can be used with a bit more effort (and talent) to look good and is more durable.
Thumb tacks, staples, and painter's tape can be used for the duration of your rental to hold things in place that don't do much damage to the property beyond normal "wear-and-tear."
EDIT: If your cat enjoys the location, provide a limited access (with a box?) where your "room mate" can go to contemplate. You would limit access to the more safe and acceptable place of your choice away from the ducts and cables. A little experimentation will find a compromise you both can accept. Cats love to climb and view their domain. Let 'em.
Comment: "Time spent with cats is never wasted." (Sigmund Freud)
Answer: Most of advices how to keep cats away from something includes either using water, some plants or something that smells bad to cats.
I believe using water guns or something like that wouldn't work in that case, but you probably could try using some citrus smelling substances like citrus air freshener if it is ok for you that your kitchen smells like lemon or orange.
The only thing you would have to keep in mind is that for sure you would have to use this air freshener regularly, perhaps using electronic air freshener with citrus refill might work.
Answer: Use something that would discourage or repel the cats like a repulsive type of air freshener, like lemon scented fresheners.

keeping cats out of open loft


new phone has locked and asking for password but I haven't set one yet!

Question: my new nokia lumia 925 has locked itself. This morning I tried to use my phone and it is asking for my password! I haven't even set a password yet! Is there a default password on these phones? I can receive calls but that's all. Please help
Comment: What kind of keyboard is used to enter the password? Is it just numbers or is there even letters?
Answer: No there default password. Could someone else have set it? Did you buy it from someone?
The only way to access the phone if you can't figure it out is doing a hard reset.
(I'm assuming you're not taking about the Microsoft account but the lockscreen pin)
Comment: Yes just lock screen. It's a new phone and there has not been any screen etc asking for a password set so I definitely haven't set one. I will take it back to shop. Makes no sense to me,never come across this before. Thanks for your help.
Comment: You can just do a hard reset using the buttons(just google it). This might save you the trip.


What are some popular anti sicilians and what are their respective strengths and weaknesses?

Question: I dislike the positions in the sicilian in which both sides kamikaze each other. What are some popular anti sicilians which will bring the black players out of their comfort zone?
Answer: For me it was very helpful to pick one opening (continuation) from moves available in big chess database like here
http://www.365chess.com/opening.php?m=3&n=3&ms=e4.c5&ns=3.3
I wouldn't recommend going with most common move  2.Nf3: that is what your opponent (a Sicilian player) is most used to, prepared and comfortable with.
For example Sicilian player played Smith Mora Gambit in less than one percent of all his games against 1.e4. But I played Smith Mora Gambit in 100% games against c5. Which can be considered an advantage.
Best thing is that you don't have to spend many hours studying all Sicilian dragons and other variations. But if your opponent wants to be ready for you he will have to study all variations of Smith Mora on top of all his previous studies of usual Sicilian theory.
(Don't forget to check sanity of variation with the best engine available.)
Comment: I disagree. Black can chose one of many defenses against the smith morra while white has to be ready for all of black's responses.I play it myself but I find that strong players usually have something prepared.
Answer: First off when dealing with the Sicilian defense there is a lot of ground to cover and this question is very broad as the open Sicilian has 4 major variations and the closed Sicilian has at least 3 major variations that immediately come into my mind.
The following are good readings for anti-sicilians:
Alapin Variation,
Moscow Variation,
Rossolimo Variation,
Grand Prix Attack,
The Closed Sicilian (this has 3 major variations),
Smith-Morra Gambit,
Wing Gambit
Now if you wish to avoid the Sicilian entirely, you may want to consider switching your own opening strategy. As white and black I see the Sicilian a lot in online play, I started using the queens gambit as white to go into fresh lines of play which leads to a more relaxed build up of both players armies into the middle game, it also has several trapping lines that you can use to catch an uneducated player with.
I hope that helps, just keep in mind that when dealing with the Sicilian there is a lot of theory to cover and it is considered the most solid reply to white's king pawn opening.
References:
http://www.chess.com/blog/Torkil/anti-sicilians
http://en.wikipedia.org/wiki/Glossary_of_chess#Anti-Sicilian


2006 Ford Fiesta Ghia starting difficulties

Question: I recharge my car battery on the Ford Fiesta 2006 and the car started first time. I let it run for a good 10 minutes then discovered central locking wasn't working on the drivers door. I tried reprogramming and tried to start the car again, and it was not turning over at all, only dashboard lights were coming on.
Answer: The symptoms you report are those of a partially or fully discharged battery. Ten minutes' running is insufficient to even partially charge a discharged battery.
To troubleshoot, you must start with a fully charged battery installed in the car. Either put the battery you have on a suitable charger for enough time, or replace the battery you have with a new, fully-charged battery. Remember that "putting it on a suitable charger for enough time" will fail if the battery you have is defective and cannot hold a charge. How old is the battery?
With a fully-charged battery in the car, see if the engine starts. If it does start, the main issue was the battery in the car was insufficiently charged or was defective.
You won't be able to further troubleshoot why the battery might have been insufficiently charged (a problem with the charging system, or not driving the vehicle enough to keep the battery charged) or defective (likely due to age, but possible even when new) until you have a fully-charged good-condition battery in the vehicle.
Answer: You should check alternator. After 10-15mins of engine running, your system (cigarette lighter or battery) should have more than 13.7V and less than 15V. If not, your alternator is broken.
Comment: "running" is that leaving at idle? many alternators have little output at idle, or "running" at 2000rpm? much better for full output of the alternator or "running" as driving to work with a varying rev range? And note some systems do charge at 15.3V...
Comment: On most cars, it does not really matter after few minutes, if engine is on idle or in load. Best practice is to do test drive with various conditions and be sure, that voltage is always in range.

What car systems have charge voltage over 15V? Basic lead-acid ones have 14.2V and Ford's silver calcium have 14.4V with max 14.8V
Comment: There are cars with charging voltages that exceed 15V under certain conditions - I own one and have the workshop manual stating that. I will  leave it to you to find out as an exercise but do be careful about sweeping statements.
Comment: We are talking about Ford Fiesta 2006. It should have silver calcium battery by default. That one must not exceed 15V. In many cases users replaced them with classic lead-acid ones (me too). Car can run with normal battery without problem.

I know, that flooded lead acid battery can have charging voltage way over 15V but it is not case in most cars


Does this phase 'books for thinking' make sense to you?

Question: I want to convey the idea of which I am selling books for people to think deeply, therefore, in short, I want to say 'books for thinking', but when I google it, there is no such phase, I am concerned that it doesn't make sense to native speakers. Actually, I found someone said 'book on thinking'.
Comment: I am not prepared to do the research on this, but as a slogan watcher, I see X for ING all the time. Music for studying, though, is one.
Comment: I think you have to be careful with google. Not everything is already "out there" especially in advertising. One tries to do something others have not yet done.
Answer: A slogan or title like that isn't expected to be a complete, grammatically correct sentence. I know what you mean. I presume most people would know what you mean. So it's perfectly good and valid.
"Book on thinking" would be a very different thing. I'd understand that to mean a book about how the mind works. In once sense or another: I'd imagine it could be anything from a book about the physics and chemistry of the brain to a philosophical discussion about the nature of the mind.
Answer: Try instead

Books for (Deep) Thinkers

It's not an especially elegant turn of phrase, but it is frequently used.
For some reason the noun for the person has come to sound better than the gerund for the activity.  Likely, this is because thinking is itself not particularly special, since everyone regularly thinks.  This undermines your intention to describe the process of thinking interesting or unusual thoughts.
In contrast, a thinker is by definition, someone who spends a lot of time thinking about deep or significant things, or someone with demonstrated intellectual prowess.
If you really want to focus on the process of thinking, then it might be better to use a more grandiose word, for example:

Books on Cogitation
Comment: I dunno. Books for deep thinkers seem to exclude everyone else.
Comment: @Lambie  I suspect that's the point.
Answer: I think "books on thinking" would refer to a book about thinking, while "books for thinking" would be closer to what you want. However, with "books for thinking," it's unclear if the reader ends up thinking more about the book itself, or if the book encourages the reader to think more about life itself.
I don't know how formal you want to get, but you might consider: Books to promote deeper thinking.
Answer: If you're trying to describe books that make people think, I think the word you're looking for is encourage.
To help or stimulate (an activity, state, or view) to develop.

To give an example:
These are books that encourage deep thinking

I also like J.R's answer, and use of the word 'promote'


Determine honey density and needed volume for target starting gravity

Question: Suppose I have honey of unknown specific gravity.
I want to mix a mead must with a target specific gravity g_t and volume V_t.
How do I determine how much honey to use?
Comment: I'm not sure what you're asking, given that you immediately posted your own answer. Are you asking for us to check your calculation? If so, then the work should be included in the question not as an answer.
Comment: @BBS I posted a self-answered question to help others. This is standard operating procedure on other SE sites; is it not here?
Comment: Ok, I'm fine with that. I was just legitimately confused.
Comment: @BBS if the question could be clarified please edit :D
Answer: Determine gravity of honey
Combine a known volume V_w of water with a known volume of honey V_h. measure the gravity of the mixture and denote that quantity g_m.
The gravity of the honey g_h is
g_h = (g_m (V_w + V_h) - V_w) / V_h.
For example, if you mix 1 gallon of honey with 2 gallons of water and measure a specific gravity of g_m = 1.14, then the specific gravity of the honey is
g_h = (1.14 (2gal + 1gal) - 2gal) / 1gal = 1.42.
Volume of honey for target starting gravity
Given a target total must volume V_t, and target starting gravity g_s, the volume of honey V_h needed is
V_h = V_t (g_s - 1) / (g_h - 1).
For example, if we want V_t = 5 gallons total must volume with starting gravity g_s = 1.1, then the volume of honey we need is
V_h = 5gal (1.1 - 1) / (1.42 - 1) = 1.2gal.
Comment: I follow the basic equations but shouldn't you be doing this by weight and not volume?  Weight of water used and weight of honey used.  Seems like that would be more accurate.
Comment: I'm no chemist, but if you start and end with the same choice (volume or weight), it seems like it would work out the same.


Can I remove this interior brick chimney?

Question: Bricks are all messed up I'm curious if I can just remove the hump part? This is on the ground floor.
Comment: It's not clear what you're asking. Is this chimney still in use? What did that hump do previously? Please revise to ask something more specific. You can do anything you want with your home.
Comment: How thick is the rest of that brick wall? It looks like it's 4" thick.
Answer: A masonry chimney can be used to carry exhaust from multiple sources. These may include an open fireplace on this floor or a gas-fired boiler in the basement. Some chimneys have more than one flue (the duct inside the chimney that contains the fumes) and the flues can combine inside the masonry so that the number of flues that exit at the top may be fewer than the number of inputs.
Before you consider demolishing that brickwork do some work to understand what purpose it served. Look on the other side of this wall as well as below and above it to understand what it may be servicing. If you can inspect the top of the chimney you can confirm how many flues there are. There are at least as many purposes to this chimney.
If you are not familiar with masonry work I would suggest having a professional come in to give you an estimate on demolition. They can help you to figure out what the chimney is there for while giving you an estimate of what it costs to have it professionally removed.
Assuming you conclude that demo is a good idea it's a straightforward task for someone with the right skills. But keep in mind that the replacement brick and mortar will not perfectly match what is there now. You can remove the "hump" but you will still see where it was in the brick unless you follow up by painting or whitewashing the entire brick wall.
Comment: Good point. There could be another flue in the fireplace that is in use and you don't want to disrupt its effectiveness.


Can I take golf bag instead of other luggage?

Question: I am travelling from Gothenburg to Bangkok with Qatar Airways on an economy class ticket. I am taking with me a golf bag (20 KG) and one suitcase (about 30 KG). Is this okay? How much baggage am I allowed to take?
Comment: You need to provide more information - What airlines are you travelling? In what class?
Comment: Qatar airline, economy class
Answer: According to Qatar Airways, its Baggage allowance on the route is as follows:

Flights to and from all other destinations

First Class   50kg (110lb) and a maximum dimension of 300 cm (118in)
Business Class 40kg (88lb) and a maximum dimension of 300 cm (118in)
Economy Class 30kg (66lb) and a maximum dimension of 300 cm (118in)

Baggage guidelines

Maximum dimension = length + width + height;
A single piece of checked baggage should weigh no more than 32kg (70lb). Any bags weighing more than 32kg (70lb) must be broken down so that each piece weighs less than 32kg (70lb).
Excess baggage charges may apply if you exceed the weight and/or piece allowances; contact your local Qatar Airways office for more information;

Excess Baggage
Excess baggage charges may apply if you exceed the weight and/or piece allowances
Excess baggage rate per additional kg (2.2lb)
From Europe to Far East

Purchased Online $40 USD
Purchased Offline $50 USD

You would want to read all the terms and conditions on excess baggage (via the link above), as one notes that:

Excess baggage is subject to space limitations at check-in. If excess baggage cannot be accepted because of space limitations or airline initiated flight or schedule changes, it may be refunded or transferred to another flight with the same origin and destination, in accordance with the airline's policies


FIPS code data combination

Question: I have two datasets- matching years, different sources. They are matchable by FIPS code, but my problem is 1) that the first data set, from which I am drawing my independent variable data, only has the five-digit FIPS code data, and my other data set has information disaggregated down to the eleven digit level. Any thoughts on combining these more disaggregated data?
Comment: For people not from the US: http://en.wikipedia.org/wiki/FIPS_county_code
Answer: You easiest answer is to create a new field in your table with the longer value; than extract the left 5 characters and insert them into the new field. Then you can join on that field without having made any integrity changing updates to the underlying data.Any database has a function to select a substring of a value.

FIPS code data combination


I was on a J1 visa for a year, it has now expired I want to return on an VWP

Question: My J1 visa has just expired on the 30th of September and I want to return to the states again in 2 weeks on an VWP for a couple months, will I be denied because it is a short amount of time between them? I don't intend on working I want to see my boyfriend and friends again and possibly travel around, I have a place to stay in the states. Do I need to show proof of places I'm staying or anything? Am I allowed to say that i'll be staying with my boyfriend?
Comment: @pnuts: The 2-year home residence requirement is irrelevant because the OP is not seeking to get an H or L visa or permanent residency
Comment: It's allowed, as long as you don't intend to immigrate to the US.  Your circumstances might lead an immigration officer to suspect that you are intending to immigrate, so you should be prepared to show that you aren't.
Comment: When did you leave the US?
Comment: `Am I allowed to say that i'll be staying with my boyfriend` It is not that you are allowed or not to say that, **you must** be honest about your plans. Of course, that does not contradict preparing yourself in advance and asking advice about how to properly explain and document to the Immigration Official that you do not have a different agenda (immigration) in mind.
Comment: i left the us on the 22nd of september
Comment: I'm from the uk, i first went to the us end of august 2015
Answer: One point in your favour is that you left the US (22nd of September 2016) before your J-1 visa expired (30th of September 2016).
"possibly travel around" however does not sound convincing. It is not only vague but having been in USA, even as a conscientious student, for more than a year (since August 2015) it begs questions such as how it was you did not make the opportunity to travel around while already in the country and what it is of a tourism nature that could suddenly spur your interest just three weeks after you left the country.
"to see friends again" is also unconvincing. You can be expected to have had friends in your home country – that in September you had not seen for more than a year (unless they had visited you in USA or you had made one or more return visits during that time or met up elsewhere). Allowing a mere three weeks for them (after a year's absence) before returning to USA for two months for other friends (after three week's absence) seems unbalanced.
"to see my boyfriend" seems very plausible but may count against you. After such a short absence It suggests your ties to him may be stronger than your ties to your home country. This is ominous as far as visits are concerned because it seems he is resident in USA hence could be reason for you "going underground" there and becoming an illegal immigrant, possibly working in USA to sustain yourself (hence in competition for employment with citizens of USA) and perhaps not paying your taxes as part of trying to be 'invisible' to the Government.

Do I need to show proof of places I'm staying or anything?

It is a routine requirement to provide details of where you expect to spend your first night in USA but evidence of that is very rarely requested.

Am I allowed to say that I'll be staying with my boyfriend?

Not only allowed but strongly encouraged to do so. While with enough chutzpah it must be possible to lie one's way through Immigration, the risk of any untruth, however seemingly innocuous, is sky high. What may appear a little 'white' lie that is "near enough" the truth still damages credibility. Any inconsistency could be 'fatal' because it makes everything else you say of questionable veracity. Doubt is more than enough reason to deny you entry when, under the VWP, CBP don't need any reason to do so anyway.
HOWEVER, as @phoog has mentioned, It's allowed. You do stand a chance. IMO not enough to justify a transatlantic airfare to test for at least a little while longer, but an attempt at entry in not guaranteed to fail. I think waiting at least a few months would be required to reduce the risk significantly of being turned back.
You do seem to have other options and even if they do not suit you being prepared with reasons why not (at least for the first two) might help any case you have to put to CBP.
One is, at least this time around, have your boyfriend visit you rather than you visit him.
Another is to apply for a B-2 visa. This gives you a chance to make your case without flying across the Atlantic. If granted it is still no guarantee of admittance, that remains a decision for CBP, but with a B-2 you should not expect any problems at the border.
A third is to fly via Dublin where USA operates Preclearance procedures.


Assign material to part of mesh

Question: I am doing this Blenderguru tutorial to work on my modelling skills. At about 28:30 min in the tutorial it is demonstrated how to assign a material to a selected part of the mesh (another material is already assigned to the object). Now I have read this post and I think I have selected the right area (with face select) and assigned the new material but it does not work. Why ?
Comment: These answers were very very helpful !!
Answer: You only have one material assigned to your object.  To assign multiple materials to different parts of a mesh you must have multiple materials assigned to the object.
At the top of the Material properties tab there is a selection box which shows all materials currently available to the object.  This does not mean that all these materials are used on the object, it means they are available to be assigned to parts of the object.  By default, the entire mesh uses the first material in this list.

On your object, there was only one material ("Transparent") in this list.  To add a material to this list, click the + button to the right of the material, you can then select a portion of the mesh and hit the Assign button to assign the selected material to that portion of the mesh.
Under the Settings rollout there are options to change the material's color in the viewport.  It is often useful to change this for some material[s] when there are multiple materials on an object so you can see which ones are on which parts.
Answer: I think it is the window refreshing problem. As you can see below, after assigning a new material I entered Edit Mode, then Object Mode (Tab) and everything went back to normal.

TIP: Remember, that in Cycles (as opposed to Blender Render), to see the assigned material colors in solid shading view you have to go to Material header-->Settings and change the Viewport Color there to corresponding material color (hover your mouse over the material color window, press Ctrl+C to copy it, then Ctrl+V to paste it to the window in Settings panel.
Comment: @Gonzou I took twenty seconds too long to answer!
Comment: In his .blend file there was only one material on his mesh.

Assign material to part of mesh


How do I make an efficient farm?

Question: I would like to make a multi-tiered farm on my homeworld. Having layers of dirt with plants in between, my only problem is the vertical space plants take up is different. Having a need for a pattern/symmetry personally I would like to know what is the maximum space plants need and the minimum. Also if they could be grouped so I have categorys and such that would be great. I think the wiki says something about this but from my understanding you can go lower on some of the plants, even if the visual goes into the dirt.
Comment: There is a incomplete list with space requirements for plants; see: http://starbound.wikia.com/wiki/Farming
Answer: Use several 4-block tall sections for most plants, and have the top tier or two a bit taller for the larger plants.  Another method is extending every other platform and using that space exclusively for taller plants.  This improves access and convenience at the cost of compactness.
Answer: Update 2015: note that the dynamics of farming have changed, as plants now need to be watered in order to grow. You can do it manually, but it is far more efficient to do with rainfall. With this in mind, multi-tiered farms that don't allow rainfall to reach lower tiers will not work.
Also, in current Stable (beginning of October 2015), whether rainfall reaches plants is not computed if a player is not present nearby. Therefore, crops will not grow in the absence of a player character. This seems like a bug or oversight, and might be targeted for a fix (or fixed already on Unstable/Nightly), but be aware of it in current Stable.
EDIT: if you use a structure in a rainy environment where you spend a good amount of time, consider growing crops on the roofs of structures to maximize the amount of farm tiles for which rainfall > saturation > crop growth will be calculated in your presence. If you're on multiplayer, any place frequented by friendly player characters should work.

How do I make an efficient farm?


$SL(n) \times SL(n)$-invariants of $m$-tuples of matrices

Question: I work over field of complex numbers. Let $G=SL(n) \times SL(n)$, and $(A,B) \in G$ acts on $m$-tuples of matrices $M_{n \times n}(\mathbb{C})^{\oplus m}$ as follows
$$
(A,B) \cdot (M_1, \ldots, M_m) \mapsto (A^{-1}M_1 B, \ldots, A^{-1}M_m B)
$$
Where can I find a description of the ring of invariants? For me it is very important that I consider $SL$ case (opposed to $GL$ case where this is just representations of a Kronecker quiver with  $n$ arrows and the answer is trivial.)
Comment: What precisely is the (trivial) answer in the $GL$ case?
Comment: For quivers without oriented cycles any invariant function is constant, so by trivial answer I mean basic field.
Comment: I think you can find the answer to your question in the book "The Classical Groups: Their Invariants and Representations" by Hermann Weyl (I don't have this book on my table).
Comment: The determinants of your matrices $M_1$, ... $M_m$ are polynomial invariants in the $SL$ case, and a natural guess would be that the algebra of polynomial invariants is generated by these determinants. Is this correct?
Comment: We can do even more general constriction: lets take coefficients of polynomial $det(z_1 M_1+\ldots+z_m M_m)$, they are all invariant and determinants correspond to coefficients of $z_i^n$. But simple examples for small $m$ and $n$ shows that there are other invariants, not covered by this construction.
Answer: I think the result in general is unknown. I have tried the case m = n = 3 (arXiv:0906.5525v2, sorry in french).
Bruno Blind
Comment: The present question should be a bit more approachable than what you studied in your article. Here the actions on the left and the right are with two different groups.
Answer: The answer in the generality of quiver representations is given by

H. Derksen, J. Weyman, Semi-invariants of quivers and saturation for Littlewood-Richardson coecients, J. Amer. Math. Soc. 13 (2000), no. 3, 467--479.
A. Schoeld, M. Van den Bergh, Semi-invariants of quivers for arbitrary dimension vectors, Indag. Math. (N.S.) 12 (2001), no. 1, 125--138.
M Domokos, A Zubkov, Semiinvariants of quivers as determinants.

In your special case, I can tell you the generators. Consider the expansion of
$$\det(\sum_{k=1}^m \Lambda_k \otimes M_k),$$ where $\Lambda_k$ is a $d\times d$-matrix of indeterminants, and $\otimes$ is the Kronecker product. Then all coefficients in the expansion are invariants. They generates all invariants if $d$ is big enough. In fact, for fixed $d$, the coefficients linearly span the space of degree $dn$ invariants.
Answer: My answer to MO question Invariant polynomials for a product of algebraic groups might help a bit. Here there should be invariants of degree $d$ if and only if $d$ is divisible by $n$. For $d=kn$, a linearly generating set can be given in terms of bipartite graphs with colored edges. The vertex set $V$ with $2k$ elements is partitioned into $I$, $J$, each with $k$ elements. All vertices have degree $n$. Finally the edges are colored with $m$ colors. The corresponding invariant is obtained as in my MO answer above by assigning tensors $\epsilon_{a_1,\ldots,a_n}$ to each vertex of $I$, assigning tensors $\eta_{b_1,\ldots,b_n}$ to the vertices of $J$ and contracting indices as indicated by the graph. However one needs to put in the middle of an $a$-$b$ contraction a matrix element $(M_c)_{a,b}$ where $c$ is the color of that edge.
The invariants obtained from the multilinear expansion of ${\rm det}(z_1 M_1+\cdots+z_m M_m)$ correspond to the graphs with $k=1$, i.e., just two vertices with a multiple edge repeated $n$ times.
The above is just a consequence of the Cayley-Clebsch Theorem, a.k.a, the first fundamental theorem of invariant theory for $SL_n$.
Now one should be able to reduce this infinite generating set using the Grassmann-Plücker relation and the straightening algorithm, but I don't know how complicated this gets in the present situation. A possible entry point in this business: Chapters 8 and 9 from the book "Young Tableaux" by Fulton. You can also search with the keywords "standard monomial theory".