What are some of the things that influence a player's "tone"?

Question: Listen to Larry Carlton, Jeff Beck,Steve Morse, Grant Green, Freddie/BB/ King, Hound Dog Taylor, Luther Allison, Dave Gregory ect.. - love'm or hate'm they all have very distinctive tones, Why? It's not all about the amp and the effects - what else gives a guitarist his/her tone?
Answer: It's in their fingers, by which I mean the way they attack the string, the way they use vibrato, the inflections they use.  All of these things contribute to tone in subtle ways.
Picking: Where and how you pick makes a huge difference: picking close to the bridge makes the guitar sound bright and sharp, closer to fingerboard makes it sound rounder and warmer.  Jaco Pastorius got a lot of his distinctive bass sound by picking really close to the bridge, thus accentuating the upper harmonics and making the tone more nasal and bright, but then turning the tone knob all the way down to round out the sound.
Using heavier or lighter picks, fingerpicking, tapping -- these all contribute as well.  Charlie Hunter, for example, uses the fleshy parts of his fingers rather than the tips with the nails, because he wants that rounder sound.  Wes Montgomery used his thumb and got a huge, round sound.  I myself use a very stiff pick instead of a lighter pick, because the heavier one aids in note definition; when I fingerpick, I always use my nails for clarity, but never metal fingerpicks, which have (to my ear) an unpleasant, scratchy sound.
Vibrato: As for vibrato, well, it's hard to be too specific, but I'll give it a shot.  When I think of distinctive vibratos, I think of Angus Young's narrow, fast tremor, B.B. King's subtle waggle, and Dimebag Darrell's huge, wide shake that just sounds so deliciously evil (it almost seems as if he's practically bending a half-step).  Each of these players' vibrato was/is so distinctive that I think if I heard them playing any guitar, I'd recognize them.
You can, of course, practice vibrato and work on getting a particular sound and style, but in interviews with players who have distinctive vibratos, when asked how they developed it, they almost all say something like, "It just felt right/natural."  This makes sense to me: if you do it the way someone else teaches you, for better or for worse it's less likely to sound like you and more likely to sound like the-way-you're-supposed-to-do-it.
Inflection: By inflection, I mean the subtle aspects of playing a note that aren't it's specific pitch and duration.  Vibrato is a part of that, for sure, but so is whether or not the player bends into or out of the note, slides up to or down to the note, plays grace notes, gets to the note via hammer-ons or pull-offs or tapping or some other way, or any of the myriad other ways to get the notes to sound.
By way of an example: Clapton's solo on "Sunshine of Your Love" is like a case study on bending as a type of inflection.  Almost none of the notes are played straight; he either bends up to the note or releases the bend down to the note.  The tone is already highly compressed and smooth due to the extreme distortion, but the bending increases the lyrical quality of the sound and contributes to its vocal-like tone.
Comment: To whoever downvoted: please leave a comment explaining your vote, so that I might improve the post.  Thank you.
Answer: What influences a player's tone has a lot to do with the equipment they use. A Strat sounds slightly different to a Tele, and a Les Paul sounds drastically different to a Rickenbacker.
The construction of the guitars and the pickup used has a big effect on this. A semi-hollowbody guitar on the neck pickup is going to sound worlds apart from a solid body guitar on the bridge pickup.
The wood used alters the sound of the guitar. For example, borrowing what I posted in response to an earlier question:

Mahogany guitars are generally heavier, with alder being quite light. Because of this, alder gives a light bright sound, and mahogany gives a deeper Les-Paulier sound.

The amp and effects that the guitar is played through also makes a massive difference. Each different amp and effect colours the sound differently, depending on whether it is valve or solid-state, size of the speaker, the EQ settings, built-in effects, it goes on forever.
The technique that the player employs can also make a big difference. Obviously the sound is going to be louder and harsher if you smash the heck out of the strings with a plectrum than if you gently fingerpick open chords. But the way you pick makes a big difference, along with the way you actually manipulate the neck. For example, The Edge of U2 uses a plectrum to pick out doublestops, and to play chords that he has selected or created variations for specifically to sound open and ringing as possible. The result is a chiming, sustained and very open sound. A player that wants to sound very heavy and rhythmic will employ power chords, whereas another player may choose to fingerpick out melody lines.
Strings and plectrums also make a difference. Heavier strings give a much thicker tone that has more presence than lighter strings. I have found that lighter picks are easier to play quicker with, allowing melodies and notes with more sustain, to be picked out (see Johnny Marr of the Smiths), whereas a heavier pick is better for rhythm and power chords. That may not be true for everyone, but that is what I have found in my own experience.
Hope this helps.
Answer: Equipment plays a significant role in a guitarists tone, as does technique, but another important factor to consider is post-production. For example, if I take a pair of Metalcore bands, hand them all PRS SE 245's and a Boogie Triple Rec and tell them to go nuts they will sound very close to alike. They won't sound exact due to inflection and expressiveness in each players technique, however in post production these two bands could be engineered to sound very distinct. It happens every day.
My shining example for this is Tom Morello. When he was in Rage, he had a very distinct tone. I believe early on he played a Telecaster with active pickups and a killswitch through a Marshall stack plus he banged around on a Digitech Whammy a lot--but his trademark tone is likely the union of his unorthodox playing technique and his gear. I wouldn't necessarily weight one more than the other. If you listen to AudioSlave you will still know it's Tom Morello based on his technique and tone but it sounds remarkably different than early Rage--more organic and warm. That's post production. It still walks like Tom Morello, talks like Tom Morello, and swims like Tom Morello, so it must be Tom Morello. Advances in recording equipment and technique are also factors here.
So in essence, I believe artists work hard to come up with a sound that they are happy with based on technique and gear. The factors in "good tone" are indeed endless (and subjective), and gear plays a significant part, but truly innovative tone is usually tightly coupled to technique. The sum of the parts are not weighted equally in every situation mind you. Eric Johnson has a trademark sound that is built specifically from his gear--but there's no way I could emulate his playing even if I had an exact copy of his rig. My fingers just don't bend that way. In this situation his technique drives his tone, not vice versa.
Additionally, artists aren't known to be the most affluent people in society so most of them start out on economical gear--another point in favor of technique. Early slave blues pioneers certainly didn't have the money to purchase nice guitars but I would definitely argue that they defined the blues genre via their technique. You can't argue with the tone of Lucille, but she just wouldn't sound the same without the King at the helm.
Answer: I think technique trumps equipment.  Metheny sounds like Metheny regardless of what he's playing.
I don't think any beginner should spend much time thinking about tone.  The very best players I've jammed with or done workshops with say the same thing: Do what sounds cool. If you try to 'cultivate' a tone, you're doing it wrong. It's just a natural result of skill maturity.
We all know good equipment is a must.  But you can give the shiniest stack of gear to a weak player and it sounds ghastly.
It's kind of like 'what pick should I use?'.  Answer:  Whatever feels good and sounds good.
Answer: A lot of it is in the effects, amps, guitars, etc... You can find this out if you ever get to see them play on low quality instruments. BUT a lot has to do with their style, how the play phrases, note choice, their confidence, etc... You can see this when they play a simple scale then play something more interesting.
Without a good sound producing device it doesn't matter how good you are you'll suck. Think of a piano that is completely out of tune(or no sound at all)... you think people will pay to see that? But at some point "talent" takes over and what your hearing is experience.
People that say that "it's all in the hands" have no clue and they themselves are not any good. No good musician will say that(how many have you heard?). They know that good sound producing instruments are a must(that's why they spend so much money on them) but also a lot of practice.
Problem is what most people consider as "tone" is not tone at all as they are confusing "music" with tone. Tone is purely the sound. A musician has little control over that through their hands(unless you consider handing over money to buy better equipment as "in the hands"). How hard they pick, hand position, finger strength, etc all play a minor role in tonal production. e.g., changing your pick can be a big change in sound and feel for you but your average listener isn't going to know the difference.
What it is, is a lot of small variables that all add up to a significant portion to tone. They have gotten this through luck, practice, talent, and experience. But it's only about 10% of the tone if that(more like 5%).
What most people "hear" as tone is really the musicianship of these people. Just study the tone of these guys when they play something simple and you will see it's not much different than anyone elses(must compare similar tone). There are big differences but are so subjective as not to be comparable.
It's all about how they play that makes you think they have good "tone". I have see some great musicians have sorry tone but "sound good". It's because they had so much musicianship they could "mask" the bad tone(not intentionally, they were just good). Even then it's hard to tell they have bad tone until they play simple enough stuff so you can focus on the tone itself(and not how they are manipulating it).
You can still "sound good" on crappy gear since most gear now days is good enough. A cheap ephiphone will get you 50%(more like 75%) of the sound of a 10k les paul quite easily. If you have a lot of talent you can "sound better" than a guy playing on that les paul... but if you played on the les paul you will sound even better.
If you are simply wondering why these guys are good and make good music it has to do with all the factors. They have it all... luck/determination is a significant part of it. There are a lot of guys in the world just as good or better than have absolutely no notoriety.
I'm sure you've had the experience of listening to these guys at some point and asking why there tone sucked? If not you haven't see them in impromptu situations enough(I haven't for most but have for some and doubt it's any different).
Hand any one of these guys a guitar that simply will not stay in tune and is out pretty bad and if they actually stay and play it you won't say they sound great... and if you didn't get to know who it was you would say their tone sucks.
Answer: It's already been hit-on, but to really get who has a good command of their tone, listen to them on an acoustic if they are primarily an electric player. Or nylon.
The best example I can think of is Chet Atkins. It's not what he plays, it's 'how' he plays no matter the equipment. One can hear Chet playing even when he is not playing in his trademark fingerstyle (sadly referred to as "boom chick").


Is the EV3 compatible with a 3rd party I2C gyroscope?

Question: The only detail I've found so far is that the pull-up resistor should be 82k ohm. I'm wondering If I could just get something like this Adafruit Gyro/Accelerometer
and just hook it up to the SDA and SCL pins of the EV3 and use it like the Lego brand sensor with minimal modification.
Answer: Yes, Mindstorms is incredibly hackable. You can use whatever 3rd-party analog, I2C, or UART devices you want with the EV3 brick. According to the hardware developer kit documentation:

The EV3 platform supports the same level of I2C communication as MINDSTORMS NXT. This means that
  system support a maximum of 9600 bit/s and maximum 32 bytes communication buffers. All I2C
  communication is running within software drivers. External devices are required to include pull-up
  resistors on both pin 5 and 6 on 82K ohm. If multiple sensors are used on the same bus the total
  impedance needs to be adjusted accordingly.

Obviously, the standard Lego programming software will not be able to utilize custom devices, but pretty much any 3rd-party firmware will allow sending custom I2C read/writes.
Answer: As MindS1 mentioned, I2C on the EV3 is a bit limited, so it really depends on what device you are connecting. There isn't really a way to tell if a device will work or not besides just trying it out. Even if it "meets the specs", there can still be timing issues that cause problems.
Dexter Industries has a nice blog post about connecting EV3 to an Arduino via I2C. This includes a block they created for the official EV3 programming software that does generic I2C communications. One limitation is that although you can read up to 32 bits at a time, you can only write at most one byte at a time (this is a limitation of the EV3 firmware, not the Dexter Industries block). So if a device requires longer write messages it definitely won't work. Otherwise, as already mentioned, you will just have to try it and see what happens.
The ev3dev 3rd-party OS for EV3 has more robust I2C handling since is uses the standard Linux I2C interface. For example, you can write a program in Python like this.


Can you create a deferred transaction with cleos?

Question: I want to create a deferred transaction that can be executed using cleos, is this possible? If so, how?
Comment: I tried using cleos push transaction with a modified json file. It got processed by cleos but it never did show up in the blockchain...
Answer: Update 19th September: v1.3.0 added a --delay-sec flag to cleos push action so you can now set a delay for your action from cleos directly.

I can't see anything in programs/cleos/main.cpp that would allow this directly.
The only way that I can think of to do this via cleos is to push an action to a contract that allows you to send deferred transactions; example:
$ cleos push action account send '["from", "to", "10.0000 EOS", "memo", 50]' -p from

And account::send can be something as follows (copied from an answer I made somewhere else):
void account::send(account_name from, account_name to, asset amount, string memo, uint64_t delay) {
    eosio::transaction t{};
    t.actions.emplace_back(
        eosio::permission_level(from, N(active)), // with `from@active` permission
        N(eosio.token), // You're sending this to `eosio.token`
        N(transfer),   // to their `transfer` action
        std::make_tuple(from, to, amount, memo));  // with the appropriate args
    t.delay_sec = delay; // Set the delay
    t.send(eosio::string_to_name(memo.c_str()), from); // Send the transaction with some ID derived from the memo
   }
};

Set permissions
 $ cleos set account permission <sender-account> active '{"threshold": 1,"keys": [{"key": "<sender-pubkey>","weight": 1}],"accounts": [{"permission":{"actor":"<contract-account>","permission":"eosio.code"},"weight":1}]}' owner -p <sender-account>


Will my mighty white rocket yellow in direct sunlight?

Question: I recently bought the Saturn V and placed it on my windowsill where the rocket is exposed to the direct impact of sunbeams every day. Having encountered several yellowing effects on older white parts I wonder if this will speed up this unwanted process of discoloring?
Comment: Possible duplicate of [What causes certain LEGO parts to yellow over time, and how can this be prevented?](https://bricks.stackexchange.com/questions/9461/what-causes-certain-lego-parts-to-yellow-over-time-and-how-can-this-be-prevente)
Answer: Absolutely it will. The yellowing is caused by exposure to UV light, which it will get more of with direct sunlight shining on it. If it has to be in the window you could look at some glass coverings that block some of the UV, or find a home for it else where under electric light.
Comment: you were so right Craig, it yellowed in months on a lot and lots of parts, annoying. now i painstakingly try to reduce the damage with hydrogen peroxide which is working more or less


Falcon 9 landing on drone ship 15/06/2016

Question: I have watched last Falcon 9 landing and launch, but during landing screen froze. I have heard that it didn't landed successfully, so what happened with it, does anyone know?
Answer: The craft experienced a RUD, which is Elon Musk's technical term for a Rapid Unscheduled Disassembly. It thus became a pile of spacecraft parts on the deck of the landing craft, and also burnt quite a bit. SpaceX will shortly release images of the landed craft.
Deimos has tweeted some low resolution images of the debris:

The debris will be taken back to Canaveral for forensic analysis to improve future landings.
Images of the debris back in port are shown here:
Comment: To be clear, Elon [did not coin the phrase Rapid Unscheduled/Unplanned/Unintended Disassembly](http://space.stackexchange.com/q/10022/4660).
Comment: Apparently, some people actually see a standing rocket in the Deimos image, albeit damaged.
Answer: SpaceX has an interesting product in the Falcon 9 recoverable, since it has a suite of option. Lowest performance missions, can land the first stage back at the launch site (RTLS - Return to Launch Site). On missions that need more performance, typically GTO/GEO missions, they can land down range on the ASDS ship.  Finally, if you needed max performance and wanted to pay for it, there is an option of an expendable first stage.
This was a dual launch GTO mission, so not quite at the absolute max of performance but pretty close.
They have said that they are working on tricks to eke out more performance for landing, by trying a three engine landing burn instead of the previous single engine burn. This saves on gravity losses by burning harder and faster.
The longer you burn, the more you are fighting gravity, and they are close enough to the edge that this matters.
As a further twist, they have tried a 1-3-1 burn pattern. First one engine starts slowing it down, two more engines spin up and slow it down hard, and then shut down and only one engine is finally used to land.
In this case, one of the engines either had a slow start, or did not properly get up to full thrust and they were probably unbalanced. Or it could be they ran out of fuel and one engine was not getting fed properly.
Comment: I object that SpaceX HAS a product. They WORK on a product. There is no cost for not reusing the stage as this is not done YET. They work on it. So far they use missions where they do not use all the performance for recovery trials. IIRC the first start with a reused stage will be in september/october and I am not sure that will not be a trial ;)
Comment: @TomTom You say tomato, I say tomatoe, lets call the whole thing off.  A fair distinction, and I agree with your point.  It is so awesome watching them playing at the edges of performance so that when they DO have a real product it will be more robust. Free tests with a 40 million dollar stage!  :)
Comment: I totally agree. Big fan here - FINALLY someone actually doing cutting edge of technology. That said, it comes with a price ;) They will get to the point, I am sure. I also look forward to their planned mars trial ;)
Answer: We know a few bits of information:

The landing was initially thought to be hard.
The landing video shows it at a near hover for ~2 seconds.
It seems it ran out of fuel (Well, oxidizer).

Putting all of this together, I imagine some kind of a sensor issue. Either the rocket thought it was going faster than it actually was, and as a result hovered and ran out of fuel, or it didn't know how far away the ground was, and a similar issue happened.
Answer: The Falcon 9 uses 3 of its engines to land. In this case one of the engines didn't work properly and did not give enough thrust and the other 2 engines did not compensate, so it hit the platform at too high a speed, broke up and exploded.
SpaceX is working on a system which will compensate for a weak engine, they say they want to test it later this year.
Comment: I will point out that typically they land on one engine, but landed on three for this mission. @geoffc's answer elaborates further.


It is good for my health to drink coffee 10 times a day?

Question: I am working on a computer 15 hours a day, and I feel tired and sleepy a lot between the work. So I prefer to drink coffee to get rid of tiredness. Coffee gives me an energy boost and makes me able to focus on work. And if I don't drink coffee then I can't do the work properly and makes me very sick. It's not like an addiction but I need something that keeps me focused and coffee does that. So what should I do, I should stop drinking that much coffee or should continue drinking daily. It is safe and good for my body to drink coffee 10 times a day?
Comment: "*if I don't drink coffee then I can't do the work properly and makes me very sick. It's not like an addiction*" Maybe,  BUT  it is just like an addiction.
Answer: Caffeine content of coffee varies widely depending on many factors. How much caffeine does your 10 cups contain? And how much is too much? The Mayo Clinic website has addressed exactly what you are concerned about in their detailed article which can be read here:
https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20045678
Important extracts:

How much is too much?
  Up to 400 milligrams (mg) of caffeine a day appears to be safe for most healthy adults. That's roughly the amount of caffeine in four cups of brewed coffee, 10 cans of cola or two "energy shot" drinks. Keep in mind that the actual caffeine content in beverages varies widely, especially among energy drinks.
[...]
You may want to cut back if you're drinking more than 4 cups of caffeinated coffee a day (or the equivalent) and you're experiencing side effects such as:
Migraine headache
Insomnia
Nervousness
Irritability
Restlessness
Frequent urination or inability to control urination
Stomach upset
Fast heartbeat
Muscle tremors
[...]
Most adults need seven to eight hours of sleep each night. But caffeine, even in the afternoon, can interfere with this much-needed sleep.
Chronically losing sleep — whether it's from work, travel, stress or too much caffeine — results in sleep deprivation. Sleep loss is cumulative, and even small nightly decreases can add up and disturb your daytime alertness and performance.
Using caffeine to mask sleep deprivation can create an unwelcome cycle. For example, you may drink caffeinated beverages because you have trouble staying awake during the day. But the caffeine keeps you from falling asleep at night, shortening the length of time you sleep.

That's also my personal experience as a long-time coffee 'addict', though I am also very sensitive to caffeine and therefore I can tolerate just 2 cups a day before I lose sleep and begin to experience strong physical effects. The key thing is to make sure you don't experience symptoms of caffeine excess, and that you get adequate sleep every day, which also varies from person to person.
If you feel the need to reduce your coffee intake, the same article linked above provides some useful guidelines.
Comment: I do have caffeine sensitivity too, it gives me a rapid heartbeat, a slight feeling of nausea and some other nasty side effects. I think I have "acquired" the caffeine sensitivity after drinking a loooot of coffee and energy drinks for three months because I had to work at night and sleep in the morning. So I advice the OP to ask a doctor or specialist instead!
Answer: Um.  I'd stop drinking coffee ten times a day.  Is it a full cup each time?  Also, even if it were safe, I guarantee it's not good/positive for your health.  Have you tried focusing on your breathing, stretching, or getting fresh air to help get you through your long work day?
Comment: Welcome! Do you happen to have any sources that you could link to about your claim? What would be the recommend maximum amount per day? You can always [edit] your post to include more information. As for all new users, I suggest you take the [tour] and browse through our [help] to learn more about how the site and the Stack Exchange network works.
Comment: No, it's half the cup. I think the same that this much coffee is going to harm me. And yeah, I have tried small walk to get some fresh air to refresh but not it does not make any good impact. But I am looking forward to stopping drinking this much of coffee because slowly and slowly this is changing in addiction.
Comment: But how big is the cup? European tea cups are much smaller than the average American coffee mug. A "cup" is eight fluid ounces. For comparison, a can of soda is 1.5 cups. A pint of beer is 2 cups. A 20oz bottle of soda is 2.5 cups. You can check this yourself by filling your coffee cup(s) with water, then dumping into a liquid measuring cup. Some cups also print their capacity on the bottom.
Comment: Also, caffeine's effects on the brain, with sufficient exposure over a sufficient period, will "train" the brain to believe that the effects of caffeine are normal. Therefore, if you don't take caffeine, you feel down and slow. You have a caffeine dependency. If you reduce caffeine intake, you can (over time) reduce that dependency. But it *will* make you feel bad until your body starts to adjust to the new normal.
Answer: I suffer the same problem, I only have 4 coffees at home but they are large mugs with 4 shots per mug per day.
I find best to have a couple of detox days each week and even on the days of heavy consumption drink plenty of plain water to keep kidneys flushed.
I acknowledge it's a vice and I have an addiction however I have not drank alcohol in many years don't have other substances or smoke so it's either coffee or motorbike riding that will most likely shorten my life (lol).
Comment: Welcome to Coffee! If you have a NEW question, please ask it by clicking the [Ask Question](//coffee.stackexchange.com/questions/ask) button. If you have sufficient reputation, [you may upvote](//coffee.stackexchange.com/privileges/vote-up) the question. Alternatively, "star" it as a favorite and you will be notified of any new answers.


Why did Beowulf bring the prized gift to the cave?

Question: The golden drinking horn proved useful in the cave, but it did not look like Beowulf (from the 2007 movie) knew it would. Why did he bring it, especially since his sole purpose to visit that cave was to kill the witch?
Answer: The golden horn was a gift/talisman bestowed upon Beowulf by the old King. The old man attributed a great deal of importance to this item, and Beowulf took it with him, partly to use in the cave and partly to display to the 'witch' his alignment with the King.
However, the horn itself was a gift given to the old king by the witch in return for a son (Grendel), and by ensuring that it was now in Beowulf's possession a gesture similar to 'passing the torch' has been made. Now it is Beowulf's turn to give the witch what she wants (a son, revealed upon the beach at the end of the film) and the horn is the symbol of his illicit pact with her.
Comment: Considering Beowulf did not know about its history, what did he plan to use it for, and why did he think the queen needed to see it?


Soapy aftertaste in wine, fermentation temperature?

Question: I generally find my homebrew wine (just from a regular kit) has a soapy kind of aftertaste. I'm wondering if this might be down to fermentation temperature or something, I'm taking as many precautions as possible sanitation-wise and folowing instructions to the letter
Comment: What sanitiser are you using?
Comment: Vin Classe Steriliser and Cleaner
Answer: This article may hold the answers you seek: https://winemakermag.com/1254-soapy-wines-vintage-dates-wine-wizard
"...I suspect you've got a fatty acid issue caused by your stuck/sluggish fermentation. S. cerevisiae can emit fatty acids when under fermentative stress..."
Stuck fermentations can be caused by a lack of dissolved oxygen in the first few days of the fermentation. When you add your wine to your fermenter give it a good shake to help dissolve some oxygen and get a healthy start for your yeast.
Comment: Too little nutrients and low pH can cause stuck fermentations, as well.
Comment: very true, but a kit should provide all nutrients and the pH required.
Comment: Thanks for the advice! Just got back into the brewing game so I'm hoping things will improve!


Is the aircraft neutral point a function of the tail incidence angle?

Question: While using XFLR v5 for a basic analysis I am facing this issue. For a fixed configuration I varied the tail incidence angle and XFLR is displaying a change in the Neutral point location. But as per theory neutral point location is not dependent on the tail incidence angle at all. I was hoping if someone could help me with this issue.
Answer: I have done some homework and I will explain why the Neutral point does not vary with the tail incidence angle.

The above equation is the fundamental equation defining the location of the neutral point.
We can see that the Neutral point is a function of the following factors only,

Aerodynamic centre
Tail volume (Horizontal tail sizing and Arm length)
Tail efficiency factor (Ratio of dynamic pressure at the tail and at the wing),
Lift curve slope for the wing and HT (CLalpha - which is fixed and not dependent on the tail incidence),
Downwash effect
Fuselage moment contribution

So none of these factors are dependent on the tail incidence angle and hence there musnt be a change at all. What shocked me the most is the fact that errors in variable quantites can be accounted for but errors in quantities that shouldnt vary is very confusing. It is a very standard statement that '' Static margin or ultimately the Cmalpha shouldnt get affected by the change in tail incidence''
This is the information I could get about it.
Answer: The calculation of the neutral point of an aircraft is about moments, not aerodynamics. The tail incidence angle has nothing to do with the neutral point, just as it also has nothing to do with the calculation of the CG.
Comment: The above answer is correct.  In the past I've seen a very clear explanation of this on model airplane forum.  I will add a link to that discussion when I come across it.
Comment: But moments arise because of aerodynamics! Stability is about reaction to disturbances; with most disturbances, airflow changes, which leads to change of moments, which provide that reaction. You can't separate them.
Comment: @Zeus CG does not take into consideration anything but weights and arms while the aircraft is not in motion. Neutral point is a measurement relative to the CG for the purposes of determining positive or negative stability. That is why you do not take into consideration those things you mentioned.
Comment: You said "calculation...  is about moments, not aerodynamics". This is "not even wrong": most moments _are_ aerodynamic. That's what I was referring to.
Comment: @zeus You still don't understand. CG and neutral point calculations are *static* calculations. No "dynamics.' Have you ever actually done a CG or neutral point calculation? Here, this explains both in very simple terms. Notice the diagrams: angle of incidence is not present in any of the explanations. https://www.instructables.com/id/Introduction-65/
Comment: I have. The 'dynamics' in 'aerodynamics' refers to the moving airflow, nothing more. Not to the dynamics of the aircraft. In static conditions you can consider static moments, but they (except for gravity) are still called 'aerodynamic'. It's just this simple terminology I'm pointing to. _Everything_ about flying (heavier-than-air) craft is aerodynamics.
Answer: I'm not that familiar with XFLR, so I'll answer with the general knowledge.
The neutral point (aka aerodynamic centre, AC) does change with the tail incidence. Why shouldn't it?
The peculiarity (and intention) of AC is that it doesn't move with the angle of attack (AoA) only. If you balance your airplane at AC, by locating CG there or by hinging (and weight balancing) the model in a wind tunnel, the airplane will be neutral with respect to AoA changes. It won't 'weathervane'.
But this doesn't mean AC won't move with configuration. If you pull the elevator/stab up, this will redistribute the moments such that the neutral point moved farther back. Think this way: AC, by definition, is the point about which the added moments due to increase of AoA from the wing, stab and everything else, balance each other out. Or, in other words, where we can think the added lift occurs. When you reduce the stab incidence (with respect to the wing), you make it to contribute more to the moment balance (again, the balance due to changes of AoA and nothing else, it's boring to repeat but it's important to understand. We are not talking about the absolute balance).
But what can you do with that? Your stab now produces a pitch-up moment. Yes, the airplane actually became a bit more stable, but it will start doing loops. If we want to restore neutrality, we'd need to move CG back, to the new AC - which would only make things worse. The only way we can balance the situation(*) is to move CG forward, until it compensates the added pitch-up. Which again increases static stability. (In practice, of course, the opposite happens: when CG is forward, we make the tail to provide pitch-up).
So, in reality, we can't simply choose tail incidence as an independent variable. It is needed to trim the airplane as much as to provide stability. But, indeed, any aerodynamic configuration changes may shift the AC and affect stability.

(*) We can also tilt the thrust to provide the required moment, but this would be double waste: the tail works against the engine. Nevertheless, technically, this way it is possible to make a statically neutral airplane with any desired tail incidence.
Comment: Why shouldn't it? Because as long as the lift is proportional to angle of attack (almost correct unless approaching stall) and the centre of pressure of each airfoil (wing and stabiliser) does not move with angle of attack (slightly incorrect), the same change in angle of attack will cause the same increase in force at the same two points independent of how you shift the zero lift line, and consequently the neutral point around which there is no moment will be the same. In practice the centres of pressure do move a little, so there is slight variation.
Comment: @RobertDiGiovanni, Neutral point is **not** center of all lifts! That would be overall centre of pressure. Neutral point is a point around which the pitching moment does not change with angle of attack (a.k.a aerodynamic centre; neutral point is usually used of the whole aircraft, aerodynamic centre of individual airfoils). In all practical aircraft, the neutral point is significantly behind the overall centre of pressure, which must coincide with centre of gravity in straight flight.
Comment: @JanHudec Can you help  in my question? https://aviation.stackexchange.com/questions/83598/why-it-doesnt-matter-if-tail-produce-lift-or-downforce-for-neutral-point-positi
Answer: As you suggested, neutral point does not change with changes in decalage (tail incidence).
For more explanation, see these links from a model airplane forum--
https://www.rcgroups.com/forums/showpost.php?p=24692807&postcount=3
https://www.rcgroups.com/forums/showpost.php?p=24694083&postcount=7
https://www.rcgroups.com/forums/showpost.php?p=24694082&postcount=6
https://www.rcgroups.com/forums/showpost.php?p=24694515&postcount=9
The links are more focussed on "static margin" than "neutral point", but implicit in the idea that the "static margin" is not changing if the decalage is changed, is the idea that the "neutral point" is not changing either.
Maybe someone can add to this answer to address the issue you are having with XFLR v5.
Answer: This may be a good time to dig into the formulas your software uses and try doing them manually.
It seems XFLR v5 is doing a few steps at a time.  Changing tail incidence indirectly affects the static stability nuetral point by assuming CG will move to new center (of lift) pressure.
Moving CG changes the torque arms of the stabilizing and destabilizing forces, which will change the static stability of the aircraft.
For example, is one reduces downforce of tail, center of pressure (of entire plane) moves back, matching CG moves back, now there is more area ahead of the CG.  One cannot ignore the CG when considering the effects of aerodynamic forces on an aircraft.
If one defines "nuetral point"  as the aerodynamic center of the entire aircraft, where a change in pitch does not create a pitching moment, then a change in tail incidence should only slightly affect its location.  This net aerodynamic center still needs to be behind the center of gravity for positive stability.
More good info in this answer.


Should rep and badges carry over from programmers to meta.programmers?

Question: I just flipped over to meta for the first time and started browsing & voting, and my rep (but not my badges) carried over from programmers. Is this the way it's supposed to work? I would expect that my "score" would either carry over in entirety or not at all, and I'd start on meta with 0 rep and 0 badges...
Answer: It's a trade-off between starting with nothing and having nothing to gain by participating.
The reason repuation does transfer is so that you have the same privileges here, as well as others being able to see your main-site participation.  By consequence you gain no reputation from Meta.
Badges don't transfer so that you can still earn something here.
Comment: You can see in http://meta.programmers.stackexchange.com/badges that there is no `Quorum` badge on Meta.
Comment: But the "Quorum" badge on programmers can only be earned via actions on meta. So does this badge transfer the other way from meta to programmers?
Comment: Yes, I get that there is no quorum badge on Meta. What I don't get is that on Programmers, I earned a quorum badge for THIS post here on Meta. Why am I earning badges in Programmer for an action taken solely on Meta? It seems more intuitive to me that the quorum badge should exist ONLY on meta...
Comment: @Greg the point is to provide some insight from main into a user's participation in meta.  You shouldn't think of them as two separate and equal sites.  Your member record as a whole involves both together.
Comment: I buy it. Thanks for the explanation.
Answer: Reputation does, badges don't: it's status-bydesign. However, there's a lag time between the time you gain rep on the main site and when it reflects as your rep total on meta.


Rational equivalence and Hilbert flag scheme

Question: Given a smooth surface $X \subset \mathbb{P}^3$ if we have two curves $C_1, C_2$ that are rationally equivalent is it true that both $(C_1,X)$ and $(C_2,X)$ will be in the same irreducible component of the Hilbert flag scheme $Hilb_{P,Q}$ where $C_i \in Hilb_P$ and $X \in Hilb_Q$? Intuitively, I would think this to be true since $C_1 \sim_{rat} C_2$ implies that there exists a flat family of curves parametrized by $\mathbb{P}^1$ such that $C_i$ is one of the fibers. But $\mathbb{P}^1$ is irreducible.
Answer: It sounds to me like you are answering your own question.  Certainly your argument proves that there exists an irreducible component of the flag Hilbert scheme containing both $(C_1,X)$ and $(C_2,X)$.  If there is a second (or third, ...) irreducible component containing $(C_1,X)$, say, it does not necessarily follow that this irreducible component also contains $(C_2,X)$.


What causes tail-down force?

Question: What phenomenon causes aerodynamic tail-down force? Why will there be more downforce on the tail when an aircraft picks up speed? What happens if the aircraft goes too slow - does this means less downforce on the tail? Do the center of lift and center of gravity play any part in determining the downforce on the tail?
Comment: The exact same phenomena by which the wing produces lift that varies with speed and angle of attack.  The tailplane is a wing.
Comment: *Do the center of lift and center of gravity play any part in determining the downforce on the tail*: not the force, but what counts here is the moment of this force related to the CG (think of a [lever](https://en.wikipedia.org/wiki/Lever)). The moment depends on the distance between the tail and the CG.
Answer: On a conventional wing and tail configuration the center of lift is normally behind the center of gravity. This causes a pitch-down force, which is counteracted with the stabilizer's downward lift.
As speed increases, the wing produces more lift, thus more tail-down -force is required to maintain attitude.
On a rear-wing configuration the same is accomplished with a canard. The only difference is that the canard provides upward lift and so it adds to the total lift, contrary to a conventional tail just increasing drag.
Answer: The phenomenon is called trimming.
This is the process by which the pilot adjusts the lift at the tail surface to shift the center of pressure right above or below the center of gravity and removes any stick force so the airplane will keep this attitude unaided.
If the center of gravity (CG) is right above or below the aerodynamic center (AC), the aircraft's longitudinal static stability is indifferent. Move it forward and stability increases, move it further back and the plane becomes unstable. The aerodynamic center is where the angle-of-atttack-dependent lift forces act, and in an indifferent configuration the lift coefficient on wing and tail will be equal. Increasing stability thus means to reduce lift at the rear surface, and if a lot of stability is desired, lift at the rear surface will become negative.
When the airplane is hit by a gust (change in vertical wind speed), the angle of attack at both wing and tail will change by the same amount. Now it is important how much lift changes relative to the lift before the gust. If the lift coefficient on the wing is larger than on the tail, the same amount of angle of attack change will cause a relatively smaller change of lift on the wing than on the tail, and the center of pressure will move such that it causes a correcting pitch moment.
By selecting the proper center of gravity location, the pilot can adjust the level of stability he/she desires. To stay at the desired attitude in flight, he/she now has to move the incidence of the empennage (or the elevator deflection) to a point where any pitch moment disappears. The consequence is a downforce on the tail if that is what it needs to trim the aircraft with the given center of gravity location.
Answer: The tail is a lifting surface just like the wings. Downforce is just the phenomenon of lift directed in the opposite direction. You can also see examples of downforce in things like the spoilers on a Formula 1 car. Going faster produces more lift and so more downforce.
What's unique about the tail is that it can be affected by the downwash of the wings themselves which comes into play when looking at design choices like a T-tail.
Zooming out more broadly, the reason you want downforce is longitudinal stability. On some planes and in certain configurations the tail produces positive lift instead of downforce, all in the name of balancing the plane, though those designs tend to be harder to fly.
You may notice that the tail is usually much smaller than the wings. This allows for better longitudinal stability as the tail experiences larger relative changes in lift (downforce) compared to the wings which provides a negative feedback loop that brings the plane back to equilibrium.
The location of the center of gravity relative to the center of lift matters because it produces a certain pitching moment that then needs to be counteracted by the force produced by the tail.
Comment: this answer misses the central point that the downforce is caused by the tailplane airfoil being "upside down"
Comment: Thanks for the feedback, you're right. I tried to clean up the answer a bit and make sure the specific question was answered first.
Comment: @rbp: No, the airfoil is only a consequence. The real cause is stability, as Miron says. Putting a negative camber on the tail will only make it more efficient - the size of the downforce is not affected.
Comment: Maybe this is a language issue. "Consequence" means it happens because of some cause.

What causes tail-down force?


Could "Please do it by EOD" considered offensive in the emails?

Question: Without asking for the estimates from the developer, I have assigned some task to a developer and written "Please do it by EOD". The developer felt offended. However, I think it's okay as I am doing my job as a lead. I have not ordered him as I did mention "Please".
Comment: Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/89248/discussion-on-question-by-deepak-mishra-could-please-do-it-by-eod-considered-o).
Answer: I don't think that it's offensive, though I would probably find it at least mildly irritating. The person organizing a team's work has the authority and the responsibility to set deadlines, though in this situation it may have been prudent to ask the developer how soon the task could be completed if it were at a given priority level.
However, a "please" from an immediate superior at work doesn't make it any less of an order than if you hadn't said "please". Could your developer have simply said "no, thanks!" and then not done the task without repercussions? If not, it was an order, no matter how you phrased it, and your phrasing was terse at best.
That you seem to feel differently may be part of the issue. If your team members feel that you are, in general, a bit domineering or dictatorial, they might have developed a general dislike with your communication style and blow individual instances out of proportion. But this is all guesswork and tangential to the question. My own boss is very respectful towards me, and when she has asked me for something by the end of the day (which happens from time to time) I have never been upset about it. I work for her, and that's her prerogative.
Comment: "when she has asked me for something by the end of the day".. I think that's exactly the point: she asked. Obviously with the intention of you following through with it, but it's still proper to ask when setting deadlines. "Is there any way this could be done by EOD?" gets the urgency across without demanding it.
Comment: @DeepakMishra I see a difference between the terms, as I use and encounter them, with offensive being worse. *Mildly irritating* just means that I find it somewhat bothersome, while *offensive* means that it is *very* irritating, and/or that the action has a moral dimension as well. Of course, I can't speak to what someone *else* meant when choosing words to use, so I can only rely on usage as I have observed it.
Comment: I don't see much of difference between offensive and mildly irritating. I think offensive is more commonly used in this context.
Comment: @Upper_Case: When I google for the word offensive, it shows me the words such as improper or irritating as the synonyms of it. So did you mean mildly offensive?
Comment: @DeepakMishra Synonyms rarely mean *exactly* the same thing. Usually there's a difference in connotation, even if not in literal meaning. The effects of this can be even more pronounced when different languages and/or cultures are involved.
Comment: @DeepakMishra A dictionary can be more informative, giving alternative definitions and examples: https://www.dictionary.com/browse/offensive?s=t     ;     https://www.dictionary.com/browse/irritating?s=t
Comment: okay, no issues, I was actually searching for a broad word which takes everything like irritating, inappropriate, unpleasing,  something which is disliked, etc.
Comment: @DeepakMishra Fair enough, and I can't guess at why your coworker (or you, if it's your summary) chose that word versus another. I'm just operating under the assumption that the word was chosen deliberately, rather than as a coin-flip among loose synonyms.
Answer:
Could "Please do it by EOD" considered offensive in the emails?

Well, it's evident that this developer found it offensive, so the answer to that is yes.
However, I consider that such phrase should not be material for someone to get offended. Perhaps the abbreviation EOD (end of day?) sounds a bit harsh, where you could just have written "end of the day".
Comment: Although telling someone to do a development task by EOD without involving them in the estimation process is classic PHB.
Comment: Up-voted. The request is benign. The developer has the option to reject with a reason. E.g.: "Sorry, I am a bit busy now. However, I could do it until XYZ." But it should not be reason for offense - unless this kind of request arrives on a daily basis.
Comment: It also depends when the request was made and how long the developer had.  If this was an 11th hour request I would have found it rude also.
Answer: Taking a different angle on this: effective communication requires more than just categorizing statements as offensive or inoffensive; it requires considering your audience and finding the ways to communicate to them that they respond best to. Just because two requests are both inoffensive doesn't make them equally effective.
Moreover, different people have different communication preferences and different attitudes and will respond to the same message differently - you can see that from the variety of answers you got to this question.  Some people didn't see anything wrong with your original wording, and some did. You can't control that. What you can do is learn ways to express yourself that minimize the likelihood of offending someone.
It seems like you've handled a subordinate becoming offended by asking whether he should have become offended. That doesn't seem productive, given that everyone has different thresholds for when demands or terseness become offensive, and you can't change his thresholds. Even if most people wouldn't have been offended, that doesn't change the fact that he was. Deciding that his feelings aren't legitimate certainly won't improve communications between you. A much more productive question to ask would be how to express yourself in the future to avoid offense being taken unnecessarily.
I'd guess that what he found offensive might be the fact that you didn't indicate what to do if it wasn't able to be completed by the end of his normal working day. If the job is larger than you thought, he may have construed "please do it by EOD" as a request for him to work overtime to complete it. If that's the case, even "please try to do it by EOD" might have been enough, since "try to" indicates that you accept the possibility that he can't. But the surest way to know would be to ask him.
Comment: Every single time -  ever - any programmer has been asked to do something - in the entire history of the universe - it has not been possible to do it by the time asked!  You never have to qualify a deadline.
Comment: If that's so, it makes it all the more important to clarify what the expected behavior is when the deadline has passed.  Work extra hours today, or finish it tomorrow?
Answer: Regardless of the word "please", you were ordering your subordinate to change their plans and priorities to complete a task by the end of the day on which you told them about it. That is likely to be inconvenient. Doing it without either discussion or explanation suggests you think the developer's planned activities have little or no importance.
If possible, allow a longer deadline, and work with the developer on deciding when it should be done, taking into account other priorities, meetings, etc.
If that is not possible, tell them why you need it done today: "I need it done today because I will be coming in early tomorrow to prepare a report X needs by 10 a.m.".
Comment: This QA is filled with the most amazing statements.  So for the junior ... "That is likely to be inconvenient."  W T F ????????????????
Answer: Anything can be offensive all it requires is someone to be offended...not a useful question.
A better question would be:  How to word the order in the most diplomatic way...
I would say that the most diplomatic way to word it, is to not make it an order, but rather a statement of fact: I need this done by EOD/COB/7am tomorrow morning, whatever.
But note that the most diplomatic way may not be the most effective way to ensure that the task is completed.  You will have to decide on a case by case basis what is most appropriate and what contributes the most to both your long term and short term goals.
Answer: As lead, it's implied to be an order, and while not offensive, it might come across as an arbitrary deadline.
But I don't think you were rude or offensive here.  You could have worded it better, yes, but part of it sounds like an overly sensitive developer.  Not your problem.
You could always phrase it as

Please, see if you can finish this by COB and let me know the status next morning.

Which might be a tad bit more diplomatic, but no, you were not being offensive.
Responding to him saying you were offensive by saying

Fine, let me rephrase it.  Please do it by COB, Jerk!

Now THAT would have been offensive...  but the way you did it, nah.
Comment: You do not need to.  As this answer says a number of times "you were not being offensive".
Comment: Why do I need to word it better if it's not offensive?
Comment: @DeepakMishra Ir wasn't.  Your coworker was being deliberately offended.
Answer: Why die on this hill? Why not:

"[Person's name], I'm really sorry if I said something wrong... Ultimately, my goal here is success for our team, both individually and as a whole. I'm very happy that you have felt comfortable enough to bring up my communication issues; that being said I'm willing to do whatever it takes so we can both work together effectively."

From there, I'd cordially try and schedule some time to iron out the communication issues. This could be something really simple that is an easy fix for you.
Oh, and you're lucky that the person is telling you directly that you have communication issues... That doens't happen very often.
Answer: You could just change it to "please do this today".
What's the difference?
I have a to-do list that will keep me busy for the next few months, and to some degree I do thinks in the order I prefer, mostly by doing related things together, but also by doing little tasks to keep the number of unfinished tasks down, and by prioritizing tasks where the ratio between work needed and improvement for the user is particularly good. And sometimes people need something done quickly, and then I push it to the top of my list. No problem. That's what you get if you say "please do this today".
"Do it by EOD" - well, are you so bad at typing that you can't write "by the end of the day"? But the real problem is that you make a demand independent of how long this task will take me. Obviously you expect me to work overtime (unpaid, naturally) if I can't finish it before the end of my paid working day. I find that quite disrespectful.
Comment: I believe exactly that was implied.
Comment: The unpaid overtime wasn't implied.  Requiring OT, possibly, but we don't know the task or when in the day it was assigned, perhaps it was a minute after he started for the day, perhaps it was as he walked out the door to head home.  I don't think giving the OP the benefit of the doubt for timeliness and capability is a stretch. It was certainly demanding and an order, I think putting more than that into is a stretch.
Comment: Gnash, I believe there was no implication of " ............ even if that means staying after work hours."
Answer: Here's the definitive overall solution to this astounding QA:

Of course it was not even slightly offensive
Many of the comments and answers here suggest that juniors shouldn't be inconvenienced. This is absurd.
Many of the comments and answers here suggest that juniors shouldn't be told to do something if they happen to be doing something else. This is absurd.
Many of the comments and answers here suggest that juniors, or indeed any employee, should be given rationales as to why they need to do something. This is absurd.
Many of the comments and answers here suggest that juniors should be asked for a detailed discussion on how long the junior thinks something will take, before having to ever do any work. Again, this is absurd.
Many of the comments and answers here suggest that juniors should not be exposed to short, concise sentences.  "Do by EOD" is very short and has an abbreviation.  (Note that every single suggestion on this page about how to be "nicer" ......... is simply a longer sentence which says the same thing.) Once again, this is absurd.

To cut through the bullshit, the OP is a team lead who is evidently from SE Asia and/or not a native English speaker.  Using no-nonsense abbreviations and truncated words is very "Indian English".  Just as Asian developers, US developers, and French developers have their own specific communication patterns.  (US developers are unbelievably long-winded, French folks are astoundingly curt, and so on.)
It's likely that the junior in question got comically offended because it's one of those "foreign" speech patterns: if that is the case, the offense is doubly-absurd.

"Could "Please do it by EOD" considered offensive in the emails?"

The answer is, of course not.
I just got an email that had the seven characters "do This" (capitalization as such) and a pdf attached! Here's another one that just has a spec attached, and nobody even bothered typing "do this"  :)
Good grief!
Comment: Downvoted because wrong. German saying: "Der Ton macht die Musik". What OP said _did_ offend, so it was offensive. Most likely not intended, otherwise he wouldn't have asked here.
Comment: I made an account here just to upvote this. I find the notion that because somebody gets offended by something, it is somehow intrinsically offensive absurd. Maybe a better wording for the question should have been "Should this person be offended", and the answer is no. As with every request from clients/higher up-s, if he has any reason not to do it, he should explain why professionally and be done with it. At my job we get requests to do something by EOD daily, and if people took time to be offended no one would actually work
Comment: I was saying that it does not matter that "that's what happened". This is just a standard request with a deadline. Employees should be expected to act as rational adults, and if there is anything that prevents them from meeting said deadline they should give their reasons and aim to push it back. If they have other tasks they should ask their lead (most likely the same guy who sets the deadline) to prioritize what should be done first. In any case it should be a rational discussion and not an emotional one.
Comment: @KGS Doesn't matter that you find it absurd, but that's what happened. And the wording _was_ offensive.


Parachute Sound?

Question: How would one go about creating a parachute sound?
I've tried flapping clothes in front of a microphone and processing them.
Answer: My job during high school and college was skydiving cameraman and coach, I've done over 1200 skydives, so I know that sound pretty well :-) I don't know what your desired perspective is like, or if you want it realistic, but I'll give you the real world stuff so you can get an idea.
From the skydiver's perspective:
During free fall, there is loud loud wind, but you're pretty focused on what you're doing that you don't register it too much. Then, you open your parachute and it goes from super noisy to what feels dead quiet in about 2 to 3 seconds. The deceleration happens like a logarithmic curve, where it stays fast and noisy longer than slow and quiet as it opens. The beginning is very present with wind, but then it transitions to heavy rustling/shaking/flapping  material. That last moment, when you're parachute goes from half open to open, that's when you hear a big solid flap/bang mixed in with material sound. Once you're open, the relative silence is incredible.
Under your open canopy, you hear a little wind and if there is some turbulence you get single flapping sounds every now and then. Most the time, it's very smooth though. If you're flying a fast canopy, then you hear stronger wind and almost no material flapping but the main sound is the wind cutting the lines (strings between the canopy and your risers), it creates this awesome whistling. There are many lines of different lengths, so they combine into some pretty rich sounds. Love it! This is the perceptive you'd want if the camera is following the skydiver.
From a ground perspective:
If there is no wind and the skydivers open above you, it sounds a lot like thunder. A sheet-ish kind of thunder. Depending on the environment it can echo. Sometimes you hear a big "Whoohhoo" scream of happiness.
Material:
The others have given great tips on creating the sound, but I'll give a little more info. The parachute material is called zero porosity and is very plasticey, and so the rustling won't sound so much like comfy cotton sheets but rather like the waterproof coats or the covering material of a tent. This is for the material itself, but most of the big sounds are created by the wind getting trapped in the cells and the wing being solid and then releasing the air and going soft quickly and vice-versa, so I guess that sheets and umbrellas flapping will sound good for the more heavy moments (not normal flight).
Comment: Thats really cool Andrew, I like the thought of going from loud rushing wind to silence instantly.
Are there any tv/films that have convincing sound design for parachuting scenes?

I think the Just Cause video games involve lots of parachuting, but I havent played them.
Comment: @Haydn I can't think of films that use it well. I remember being obsessed by Drop Zone: http://www.imdb.com/title/tt0109676/ that was before I started jumping, I should listen to it again. I haven't heard of Just Cause, looks like fun though.
Comment: Check out the drops in Band Of Brothers - good sound design there.
Answer: It's difficult to advise without knowing what your visual requires (exaggerated drama vs realistic). Sail pops and furls are a great starting point because you'll get mass and depth. Bedsheets and smaller fabrics will provide the smaller, finer details, but I wouldn't rely on them alone. If you're working with a more dramatic visual I would look for an explosive element to sweeten the pop, like a gunshot, explosion or any sort of deep impact. Good luck and happy experimenting!
Answer: Try taking a big umbrella and flapping it up and down.  Do bigger, slower movements for wind gusts or the chute opening, and smaller, quick movements for fluttering in the wind.
Another great, but less accessible sound would be the sound of luffing sails on a sailboat.
Answer: try quickly inflating a pillowcase outside a speeding car window
Comment: Good idea twobob.  What about out bringing along some lavs while you skydive.
Comment: Thats a great idea, you would probably get a lot of noise from the car though wouldnt you?
I might try and do this on my bicycle somehow, because i would be able to travel quietly & reasonably quickly.
Answer: For the sound of the chute opening I would try using a (un-erected) tent, with one person holding it at each end and shaking it to create a wave
Answer: I was just about to suggest that tent idea but you beat me to it!
I've never parachuted, but you might want to also add in some rattling metal gear? maybe a few carbiners rattling together. The one thing that I would say is that depending on what your project is, chances are that a small percentage of your audience will have any experience skydiving. . .
This means that the most realistic effect might not be the most effective one. It might make sense to create an effect that meets peoples exceptions of what parachuting sounds like, rather than create an effect that stays very true to being realistic but might go against what people would assume it sounds like.
Answer: For impact I've used slowed-down grenade explosions.  Can't add much more for the actual material sounds - think I used a combination of an umbrella and multiple layers of foley with  poncho/wind stoppers.  Other thing i did was stick some of the material out a window whilst driving - you need good noise reduction and eq to work out the car/amb noises but you get decent flaps/wind rustle from it.  Alternatively a desktop fan might work?
Answer: For the opening you'll want to try with a thin shower curtain. I'm talking about the thin ones, 100% polyester. If you wet it'll sound a tiny bit heavier. And it flaps quite well.
Answer: I've never been skydiving, so my only experience to it's sound is what I've seen other sound designers do.
My initial thought was, for the pop of the chute opining, to use the pop of a plastic bag as you swing it downward, filling it with air (I honestly didn't know how to explain that), then pitch it down.

Parachute Sound?


Are PIX firewalls still supported by Cisco?

Question: I was told by a salesman at a hosting company to be wary of anyone trying to use a PIX firewall in my hosting solution because Cisco doesn't support them anymore or offer security updates. Is that true? His was the only company out of 5 that didn't include a PIX firewall in their proposal. So is everyone else giving me out-of-date and possibly insecure hardware or is the salesman full of it?
Answer: This post from Cisco seems to clarify the dates a bit
looks like certain extended support is still around, but purchasing one has pretty much ended
that said, the ASA is a worthy replacement and still going strong I believe
Comment: Morever, the ASA line was designed to replace the PIX line.
Answer: I think a lot of people still use the name PIX for ASA gear as well, so you may just want to clarify with them the actual product being used.
Answer: It depends what you want to do. PIX is still good.515e and 535 even the old 506e .
As I said before it depends on your requirements of design.I still use and deploy them.
Configure them good and they are solid.
Devices and age ,old or new is not the problem.
It is the person configuring them and whether it supports what you want to do.
People think ,they spend more ,they get good .that is a  no no.
Think about the old school. Everybody is moving back to command line.before we ran away.
Even exchange 2010 has power shell now.
So work with your requirements.If there design meets what you want .
whether they use helicopter ,use it.
Thanks.
Answer: Officially, the PIX 500 series is end-of-sale.  Last chance to attach a new service contract with Cisco was July '09.  End of support outright is July 27, 2013.  As already stated, the ASA is the new PIX.
Answer: An ASA will do everything the PIX did and then some, so it the replacement.  You can pretty much drop a PIX config onto an ASA and it will run, so there's no way I'd buy a PIX today.


XSS not exploitable when POST data is sent in JSON?

Question: There is a reflected XSS flaw in an application I am testing. Initially, the payload is sent in POST request as value of a JSON key and the response is also a JSON object. The returned value in the JSON object is directly used by client side Javascript and hence the flaw. My questions is, I tried all ways given on this page to send a JSON payload through HTML form  but I failed as the server is properly validating the input. Is there any way this XSS flaw can be exploited?
Also, GET method on same URL does not work.
Comment: "Properly validating the input"? What have you tried, and how exactly does it fail? It could be that the handler is explicitly checking for content-type `application/json`, which cannot be sent cross-domain without enabling CORS, therefore it may not be exploitable unless you have another way of manipulating the input sent.
Comment: @SilverlightFox Yes, the server is properly validating the input. In other words, I failed to send a JSON payload using HTML form as given in the article in my original question. ALso, I can't send AJAX request as CORS doesn't allow it. Does it mean that XSS is not "exploitable" ?
Comment: If it's reflected XSS, then no it doesn't appear so from the information given.
Comment: @SilverlightFox server is not checking for content-type but it is properly checking the JSON input format. Please see the article in my question to understand why the techniques might fail. :)
Comment: @SilverlightFox Would this flaw fit in exact definition of reflected XSS ?  or can we call it combination of DOM based and reflected XSS ?
Answer: The article is proving that an HTML form can be used to send a JSON object via CSRF, even if the server-side is only accepting text/plain requests expecting JSON.
(instead of the typical application/x-www-form-urlencoded) requests.
I've included the linked example on this site, because we do not allow link-only content.

<form action=http://192.168.1.41:3000 method=post enctype="text/plain" >
<input name='{"a":1,"b":{"c":3}, "ignore_me":"' value='test"}'type='hidden'>
<input type=submit>
</form>

results in a request looking like

Based on your comments I now understand that you are asking about Reflected XSS attacks.

The payload is returned unchanged in a JSON response.

Is there any HTML involved?
If so, then it all depends on how it is encoded as to whether you have an XSS vulnerability.
On the other hand, if this is simply an "echo" with no added HTML, then it depends on your response headers. Content-Type: text/html should be sufficient to keep the response from being executed as code, but in some browsers, it would still be vulnerable. Content-Disposition: attachment would solve the problem assuming the filename extension and content types are safe. (i.e. txt)

if the payload can't be sent via HTML forms, does that mean XSS is not "exploitable" ?
if one can't create an HTML form (with JSON payload which is accepted by server) , then this XSS is not exploitable right ?

However, with a question like that, it sounds like you are about to 'shoot yourself in the foot' by locking into an 'easy' answer. I am worried just because I don't understand why you are asking that question.

Warning: With an HTML form it may be possible to send the required JSON payload based on the specifics of the server validation you are using.

I'll answer you anyway:
Supposing that an HTML form is insufficient (meaning you've already disproved my warning), and Query String is also not sufficient (true in your case); then Reflective XSS attacks would not be possible.

The attacker would be left only with AJAX as a possibility, as well as various plugins that might be able to initiate CSRF. Stored XSS might still be possible in that situation, if your server has more advanced features beyond "echo" of the request.

Additional info:
There are three avenues that come to mind for XSS. Only items 2 and 3 require 'payload of your choice' to be uploaded via CSRF.
Items 1 and 2 apply to a Stored XSS attack which involves inserting code into one of the text fields of the server's database, such that when the server shows the results later it might be executed in the Browser due to missing/improper encoding (XSS vulnerability) by the server.

If you have appropriate credentials, or it is a public facing site (i.e. Stack Exchange comments), then anyone (even the attacker) can insert the code directly.
Then if the system were vulnerable (incorrect/missing encoding) then future visitors viewing the submitted content would be victims of the attack.

If this was a closed system, such that the attacker would not have the appropriate login credentials for the submitted data to be accepted into a database, then the attacker would have to use a CSRF to take advantage of another user's credentials (assuming the user is already logged in to the target system when visiting the attacker's site)

For Reflective XSS, you would need #2 CSRF for this. In this case the data need not be stored, but you are taking advantage of a situation where input data is returned back to the user.

i.e. a Preview page,
or a refreshed form with values pre-filled
an error page that includes user content (i.e. X is an invalid email address)

Stored XSS may be preferable for the attacker to reach a broader audience. There is the possibility also that a given system is not vulnerable to Stored XSS, but still may be vulnerable to Reflective XSS.
Comment: "An XSS attack involves inserting code into one of the text fields of the server's database"- That is stored XSS. I think the OP is trying to do reflected XSS, but since the vector is POST and not GET a form needs to be involved.
Comment: Hi , I am aware that the article is about CSRF. My point here is, to execute the XSS attack, the victim needs to send a payload of my choice. This payload needs to be sent via JSON. So, the question is , if the payload can't be sent via HTML forms, does that mean XSS is not "exploitable" ?
Comment: @Anders I think you understodd my question.Let me clarify things a little bit:   1. Payload is sent via JSON in POST paramaters.  2. The payload is returned unchanged in a JSON response.  3. JSON value is used by client side javascript directly and the payload gets executed .            In my opinion, this is a DOM based XSS ( as the reflecttion of payload in response does not cause the execution of script,  handling of payload by javascript does. )   SO, if one can't create an HTML form (with JSON payload which is accepted by server) , then this XSS is not exploitable right ?
Comment: @entropy, I apologize I did not catch onto *"payload is returned unchanged "* earlier. **I've updated my question.** See just below the screenshot for your answers.
Comment: @GeorgeBailey Of course  JSON payload can be sent via HTML form. The problem here is that it is not accepted by the server (see why the techniques fail in the link in original post) . SO , my concern is  , XSS not exploitable ( as  the JSON payload sent via custom HTML form using tricks given in the link is not accepted by the server  )
Comment: @GeorgeBailey you need to see that article again. In scenario 1, a "=" is appended at the end while in scenario 2 an extra parameter is added . Both inputs are not accepted by server. I mean no offense, but you should try to understand the question completely before trying to answer.
Comment: @entropy, Thank you for you understanding. *"I tried all ways given on this page to send a JSON payload through HTML form but I failed as the server is properly validating the input. Is there any way this XSS flaw can be exploited"* Just because **you failed when you tried** doesn't mean **it's not possible**. So, I can't guarantee that you are secure without understanding the validation you are using. But if you want me to just 'take your word for it' that the validation is sufficient, then you can use the "I'll answer you anyway" section I posted above.
Comment: @GeorgeBailey I don't understand what do you mean by Stored AJAX ? Also, why did you bring CSRF into this scenario ? Although the article refers to CSRF attacks, I was just referring to techniques given to defeat input validation. and YES, I am quite confident that the server's input validation can;t be defeated. I was hoping I could get some novel techniques to defeat that in answers.
Comment: @entropy, I meant to say Stored XSS.
Comment: @entropy, Your question was not very clear. I hope you understand that. I've included a large amount of details, but without proper restrictions on what you wanted me to cover, I have to play it safe and avoid giving a false sense of security.
Comment: @entropy, I mention CSRF, because that was referenced in the linked article. If you do not care about CSRF causing Stored XSS attacks then that is of no importance to you.
Comment: @entropy, *"I was hoping I could get some novel techniques to defeat that in answers."* If you want this, then please start a new question, and be very specific about what you are and are not interested in as an answer. Things like "I tried and couldn't" are very different from "I'm confident it's not possible". I'm asking you to start a **New Question with very specific requirements** if you need more details, because it gives you a clean slate and keeps me from having to delete the work I've done thus far.


How can I clean this chair at home?

Question:

What's the name for such material? Is it cloth?
Without buying steam cleaners or machines, or transporting to cleaners, how can it be cleaned at home? I have a steam clothes iron, if it can help?
Comment: I just realized: you did not mention what kind of "dirty" we talk about: is it plain dust, or something sticky, or greasy, or just cemented "ancient-everything-mix", like it sometimes happens with chairs.
Comment: @virolino The chair's exposed to room air, so dust, sweat. But no food or stickiness.
Comment: There are many kinds of dedicated fabric cleaners available, some works better than others, I had good experience with carpet foam cleaner. But to get a recommendation you'll have to be more specific with your location
Answer: I used very simple method:

Put some water on it (not much)
Take a soap and rub it on it
Use a bit more water and friction to make the soap work
Take a vacuum cleaner and put dry toilet paper inside (so it can absorb water)
Vacuum clean the sofa to take the water and soap out.
Add a bit more water to dissolve the redundant soap in the fabric
Repeat steps 5 - 6 until the fabric is reasonably soap-less :-)
Let it dry out
Remove the wet toilet paper from the vacuum cleaner :-)

The vacuum cleaner will actually take out so much water that it will dry much faster. I usethis procedure any time when I for example spill some liquid on my carpet or an upholstered chair and the liquid needs to be removed as soon as possible (to not catch mold), and eventually needs to be cleaned.
Answer: I did something similar with the seats in my car.

I prepared a solution of water and kitchen liquid detergent.
I applied a very thin layer on the chair, so it would not soak in the foam below (not much, at least).
I brushed a little, and then let it rest, a little. Brushed again.
Used a vacuum cleaner to extract the solution and dirt, and let the place as "dry" as possible.
Repeat 3 and 4 with clean water, 1-2 times.
Left the doors open for good ventilation for drying.

Instead of step 1, there are special detergents for carpets. You apply them, and then they dry. After that you just vacuum the solids, containing the detergent and the dirt.
I have no personal experience with these detergents, but I cannot see how you can fail.

If there is only dust, then you can just "beat" it out fo the chair.

Take the chair to an area where creating dust around is not a problem.
Using a stick (or anything similar) beat the cloth of the chair - similar with beat-cleaning a carpet.
As needed, a vacuum cleaner will help manage the mess.
Continue until no dust comes out of it.

As an example, search on you tube for things like: "dust bus chair", and you will see examples of this procedure, applied to apparently clean seats. I would not recommend the use of a hammer (as seen in one of the videos), as it might damage the cloth.
Answer: Vacuum it regularly. If your vacuum has various settings, set it to cloth/curtains/rugs (whatever yours says) to not create a vacuum. (I know, ironic isn't it?) This will help prevent some stains from setting. Before you clean it, I'd suggest testing in a place that's not visible to see if its color will come off or not. Underside of the seat, perhaps?
Use a damp cloth to rub it gently after vacuuming. You might not even have to do anything else to keep it clean.
But if you still get stains, spray warm water on it and wipe it with a damp cloth. Soap is often not needed as water will do the job. But depending on the stains, sometimes soap will help. Add just a few drops to the water. Soap can actually attract dirt and make stains more visible over time.
Put a towel on the seat and apply pressure by, for instance, sitting on the chair. I find this to be the easiest, quickest way. If the towel gets wet quickly, change it to a dry one and repeat. Maybe have a good read and a cup of tea while you wait? Let the chair air for an hour or two before using it.
Please don't use a vacuum cleaner to suck water from any surface or fabric. I see people giving you this advice and unless it's a wet/dry vacuum, I'd advice against it. A regular vacuum is not a closed system and we all know that water and electricity do not mix. That some people never had an accident or ruined their vacuum this way, is not evidence it's safe.

How can I clean this chair at home?


How does elevation affect the amount of rainfall received?

Question: How does elevation affect the amount of rainfall received? Does elevation affect precipitation?
Comment: You question is unclear. Are you talking about comparing an area with elevation H1 with another area with elevation H2 (a 'static' situation), or are you talking about a moving air mass passing areas with varying elevation (a dynamic situation). Please [edit] your question.
Answer: Elevation affects temperature which affects the amount of rain. Most raingauges around the world are within a few hundred metres of sea-level, i.e the range in which most people live. Within this range the rainfall-elevation relationship often appears to be linear. However, as the temperature gets cooler with altitude, the maximum precipitable moisture decreases drastically, so the rainfall-altitude curve reflexes back upon itself, so that there is an elevation of maximum precipitation ('EMP'). This variation variies with several factors, such as continentality, 'tropicality', aspect, rain shadow and barrier effect. Some examples of the EMP, are (in metres): Tajikistan 3800,
Alberta Canada 2360, European Alps, 2250, NW Pakistan1500, Oman 1400 to 2200, Kilimanjaro Tanzania 1500, and Hawaii 900. In the case of polar regions the EMP is ground level because the rainfall-altitude relationship is nearly always negative. Above the EMP the rainfall decreases rapidly with altitude, which is why high mountainous regions are essentially deserts.
Wherever there is significant relief in a catchment, the first step is to determine whether the catchment is all below the EMP. The second step is to process the historic record to see if a second order, or even third order rainfall altitude regression is a significant improvement upon 'linear'. If you want further refinement the seasonal rainfalls, or rainfalls from different directions, often have markedly differing rainfall-altitude relationships. If you want to go the whole hog, and be scientific about it, then the rainfall approximates a multi-variate solution, with components of
altitude, altitude squared, aspect, regional trend, rain shadow and barrier effect. This can be solved as an equation of the form: $$R = aH + BH^{2} + cA + dT + eS +f'BE'$$
Answer: Elevation affects precipitation significantly, especially in a mountain environment. On the windward side of a mountain, precipitation is increased. As air parcel rises due to increasing elevation on the windward side of the mountain, the air parcel cools, condenses, and it rains. Once the air parcel (cloud) moves over the peak of the mountain, the air parcel dries and warms quickly as it flows down the leeward side of the mountain. This is known as adiabatic warming or compressional warming. In the United States and Canada, there are north to south mountain ranges. On the westward side (windward side), it is green and the areas receive plenty of precipitation. On the eastern side, there are more arid conditions. Plateaus (flat areas of high elevation) can also have an affect on precipitation. Thermal lows can form over plateaus in the subtropics (like Mexico or parts of Asia), causing precipitation. This is a form of a summer monsoon.
Comment: But this is not really the effect of elevation itself, but of changes in elevation.  We might compare the Great Plains (not much elevation change there) with the same elevations in the Sierra/Cascades.
Comment: Is it just elevation changing the amount of rainfall, or is it that the elevation decreases as you get further from the rain shadow effect of the Rockies?  Because after you cross the Mississippi and the elevation starts increasing as you approach the Appalachians.
Comment: Right. However, the slight elevation change in the Great Plains has a drastic effect on precipitation in the area. The Great Plains dryline is a function of elevation, which then is a function of precipitation in the Great Plains.
Comment: @jamesqf Yes, elevation increases east of the Mississippi. There is also some variation of elevation in Missouri and Arkansas. However, the continuous (almost constant) decrease in elevation in the Great Plains from the Rockies to about -95 degrees is important to the initiation of rainfall. In the meteorological sense, the warm moist boundary layer air advected from the Gulf of Mexico is impeded by the westward increasing elevation gradient in the Great Plains. This means when a front reaches the boundary, precipitation occurs east of that north-south intersection while the west stays dry.
Comment: Feel using the term windward as west, and the simplicity of the explanation, may be a bit misleading for US mountain ranges.  The Appalachians are north-south (or SW-NE, whatever you want to call it).  But areas E/SE of them receive similar or even greater rainfall compared to the W/NW sides.  And winds in central California/E WA/etc climatologically aren't particularly westerly.  It's more about access to moisture, which the winds in inland west don't have, while the winds E of the Appalachians very much do.
Answer: Areas of high elevation, such as mountain ranges, often drain the air of its moisture. As the air rises up the mountain, it cools. As the air cools, it loses its ability to hold water. The water then condenses out of the air and falls as precipitation.
The high altitudes of mountains often receive a significant amount of precipitation. Often, this precipitation falls in the form of snow, which is why many high mountain peaks are always covered in snow. In mountains near the equator, the constantly high levels of humidity form what is called a "cloud forest." Cloud forests are habitats that feature numerous mosses, algae and epiphytic plants; often, these plants are covered in water for most of the day.
While the top of the mountain may receive abundant rainfall, mountains often remain dry on the down-wind side. This is called the "rain shadow effect," and it causes the downwind side of the mountain to remain dry for most of the year. One of the best examples of this phenomenon is created by the Himalayan Mountains. As the warm, moist air blows from the Indian Ocean, it flies up the side of the Himalayas. Most of the rain falls on the south side of the mountains, and the area on the north side of the mountains remains dry.
This actual case explain more details A Preliminary Analysis of the Relationship between Precipitation Variation Trends and Altitude in China by ATMOSPHERIC AND OCEANIC SCIENCE LETTERS, 2011, VOL. 4, NO. 1, 4146


How to check the version of Magento from URL?

Question: I want to know the programmable logic of getting the magento version by just entering URL of the magento store.Something similar is seen here.
http://magentoversion.com/
Comment: What's the point of that service? Just log in into the backend and you'll see it there too.
Comment: This is for fingerprinting a Magento site that you don't have backend access to.
Answer: Finally after long research I found Following code useful to determine Version of Magento.
<code>    <?php
function get_data($url) {
    $ch = curl_init();
    $timeout = 5;
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
    $data = curl_exec($ch);
    curl_close($ch);
    return $data;
}
$file = $url.'/skin/frontend/default/default/css/styles.css';
$data = get_data($file);
$data   = explode("\n", $data);
for ($line = 0; $line < count($data); $line++)
 {
    if(strpos($data[$line],"2010" )){$mver= 1.5;}
    elseif(strpos($data[$line],"2011")){$mver= 1.6;}
    elseif(strpos($data[$line],"2012")){$mver= 1.7;}
    elseif(strpos($data[$line],"2013")){$mver= 1.8;}
    elseif(strpos($data[$line],"2014")){$mver= 1.9;}
}

?>
</code>
I hope it would help you all
Answer: https://github.com/steverobbins/magento-guest-audit/blob/master/src/MGA/Check/Version.php(broken)
https://github.com/steverobbins/magescan/blob/master/src/MageScan/Check/Version.php
MGA fetches js/varien/product.js, and then pulls license information and the copyright year from the header to guess at the version. Note that it can't differentiate 1.4 from 1.5 this way - if you cared enough you could keep a list of hashes of each JS file and track changes in more detail.
Comment: Can you explain me this code in deep please I am not getting it.


What is the Buddhist Perspective on Dreaming?

Question: I met my family who has already died in my dream. He told me something bad about my partner.
Should I believe him?
Comment: A few years ago, my uncle passed away. On the morning of his death, my mom said he came to her in a dream to say goodbye and she knew before the hospital called that he had died. I wouldn't know if you should believe your deceased family member in your dream or not but it wouldn't hurt to look into it.. IMO.
Comment: No, don't believe it without examining your own attitudes. That would be superstitious. It can be that family attitudes influence the way you judge your partner (that would be a symbolic interpretation). Do not tell your partner the dream. That would be to lay an unfair burden on your partner, ascribing the criticism to a "ghost" instead of admitting your own attitude or suspicion. If you have a complaint about your partner, address it directly and honestly, without reference to the dream.
Answer: According to the Milindapañha there are six causes of dreams:

vātiko supinaṃ passati - one with winds sees a dream
pittiko supinaṃ - one with bile sees a dream
semhiko supinaṃ passati - one with phlegm sees a dream
devatūpasaṃhārato supinaṃ passati - one possessed by a devata sees a dream
samudāciṇṇato supinaṃ passati - I don't know what this one means, maybe something to do with memories?
pubbanimittato supinaṃ passati - one sees a dream as a prophetic vision

tatra, mahārāja, yaṃ pubbanimittato supinaṃ passati, taṃ yeva saccaṃ, avasesaṃ micchā"ti.

Of these six, only the last type is true, the rest are false.
I think it is possible that possession by a devata could lead to dreams containing truth, but it is just as likely to be misleading. How would you know if your were being deceived? Much better to rely on waking experience. Nagasena says mostly dreams occur when one is kapiniddāpareta - afflicted with monkey sleep.
Source: milindapañha, anumānapañho, vessantaravaggo, supinapañho
Comment: "samudāciṇṇato supinaṃ passati" --> In Sinhala, this is translated as "පෙර පුරුදු කතාසල්ලාප ක්‍රියාදී විසින් සිහින දක්නේ ය." which means "One may sees a dream due to previous habits, talks, and deeds". And yes, Reverend Yuttadhammo, it's something to do with memories.
Answer: I was really surprised to find something that might help in my search for dreams. From SN25.132:

All is vain for someone who doesn't guard the sense doors, like the wealth a person finds in a dream.

From the above advice of the Buddha, I'd say that you might be better off seeking a quiet place to reflect mindfully and peacefully on your relationship without grasping, aversion or delusion. The wealth found in dreams doesn't pay the bills. Nor does it offer clear advice.


Like button - Admin page and OG tag don't agree

Question: when I first rolled out the Like button for our site I inadvertently left the test site url in the OG url tag.  I liked the site and then went to the admin page where I discovered my error.
I fixed the og tag and rolled out a new version of the page.  The OG tag is now correct, and the FB linter comes up clean.  However, if I go the admin page it still shows the test site url.  If I go to a different browser and like the page the admin page is correct.
How can get the first browser to go to the correct admin page?
Worse, we seem to be getting likes on both the test site and the live site. We're a small organization so both sites are sub directories of the same domain, although the full path to the root is given in the og url tag:
<code><meta property="og:url" content="http://birdweb.org/birdweb/" />
</code>
Any ideas?
Answer: Sounds like a caching issue - just clean your cache in the problematic browser and all should be fine.


Why does solvent particles move towards solution when semi permeable membrane is added?

Question:
When a SPM is added in between solute and solution the water molecules move towards salt water even though the concentration is same both sides. Why does this happen? According to SPM's perspective, concentration (of water) at salt water side is lower than that at fresh water side but how does that change the fact that the overall concentration is same both sides? My book says it depends on vapour pressure. If that's the case then osmosis should take place without SPM because it depends only on vapour pressure?
Comment: Osmosis surely does take place without a membrane. Related: https://chemistry.stackexchange.com/questions/49435/how-can-you-explain-the-energy-change-in-this-phenomenon
Answer: Here what happens is that the fresh water is a pure solvent and a pure solvent always has a greater vapor pressure than that of a solution. So due to the greater vapor pressure on water's side, the molecules of water will experience a force in salt water's direction as the pressure is less in salt water side. Therefore the water will flow towards the salt water.