Do good bridge players memorize all cards played?

Question: Certainly, they track the quantity of each suit and the high value cards, but I'm curious if good bridge players also remember, say, whether someone ducked the ace using a 7 of spades vs a 6 of spades.
Answer: Obviously, this answer depends on your meaning of the word 'good'.  However, I consider myself a good bridge player, and find myself not often needing to track the nuanced difference between 6 and 7.  Most hands are not decided in table play, but in the bidding, and most are determined by leading, the high cards and the trump suit.   There are situations where I would need to track a spade 6 or 7, but often that's when I've got a hole that I need my partner to fill, or attempt a finesse.  In such situations, I'm looking specifically for those problem cards, so I don't need to track every card.
There are unforeseen situations where tracking every card could give a slight edge, but those happen so infrequently that it won't make much of a difference in one's overall 'goodness'.
Incidentally, there are mnemonic tricks that allow one to easily track all cards, I just find it not worth the effort in standard bridge.
Comment: -1: For: 1) the hands are not decided in table play, but in bidding/.... This is inaccurate and actually irrelevant to the discussion I suppose. 2) The good players watch spots like hawks, especially if those could be relevant defensive signals. They might make a conclusion then and there and forget later, but the spots are relevant.
Comment: Touche.  I should have said that once learned, applying mnemonic tricks are easy to do, but learning them in the first place (learning the skill) can be quite difficult.  For those interested: http://en.wikipedia.org/wiki/Mnemonic_major_system
Comment: @Aryabhata I hadn't noticed your comment until after I had written my answer but you'll see from my answer that I agree - better players will track both the exact cards played and their sequence for defensive signaling purposes.
Comment: @JoeGolton: No worries, I don't mind. In fact, you have my +1 :-)
Comment: This gets to semantics around 'good'.  If you're playing casually, usually partners won't have detailed sequential defensive signalling techniques.  If you're playing in a tournament setting, then you likely will want these.  However, I posit that you can register defensive signals without memorizing every card, just like you can understand a written paragraph, and repeat its meaning, without being able to exactly replicate each word in order.
Answer: While it is true that the play is largely determined by  information gleaned from bidding, high cards, leading, and the trump suit, there is one aspect of bridge where precisely tracking every card is very helpful: defensive signaling. As Wikipedia describes, "partners defending against a contract may play particular cards in a manner which gives a signal or coded meaning to guide their subsequent card play; also referred to as carding." Obviously these signals will only work if the partners are tracking cards precisely, including their sequence. And this goes for the offense too so they can gain information as to where cards are placed among the defenders.
The most common example where remembering a low discard is vital is the high low signal indicating a doubleton, and thus a desire for partner to lead back that suit a third time if trumps have not yet been completely pulled. I've typically played that this can be with a first card followed by a second lower card, even a 3-2.
Another common example is leading the fourth highest card from longest and strongest when defending a no trump contract. In this case, it is helpful to subsequently remember every card played in that suit as this often makes it possible to infer exactly which cards are held by the opponents in this suit.
One could reasonably argue that you can get by just remembering the first card played by the first and third seats (in addition to tracking high cards and trumps), and that will probably get you by for the defensive signals typically applied by beginning to intermediate players.
However, you asked if good players memorize all cards. I'm not sure how good you mean but at the higher levels of play many forms of defensive signaling are used. The more defensive signals you use, the more it requires remembering not only exactly which cards have already been played, but the exact sequence in which they were played.
Answer: My guess is that SOME good players will memorize individual cards (because they have a "knack" for it. But many, probably will NOT.
I'm not a "good" player, but know that it is important to size up the hand. That means looking out for opposing honors, and also for missing trumps. Tn this way, I focus on maybe 10 of the 26 opposing cards. Sometimes more (13-15), if there is a critical side suit.
It gets exponentially harder at each step; going from tracking 7 cards to 13, and 13 to 26 (that is, quadrupling difficulty for each numerical doubling). Most good players take the first steps (up to 13). Some go all the way to 26.
In his autobiography, Lee Iacocca told the story of how his boss, Robert McNamara was shown a 750 page presentation, and on page 724, he said, "That contradicts something you said on page nine." That kind of skill does exist, but it's pretty rare. Iacocca himself probably didn't have it.
Answer: This boils down to issues of active thinking and observation. Good players weigh expectation against actuality. But the tools for determining actuality are tools of observation, not memorization. (s)he looks at every card, but there is no value in memorizing them. The dire need is to determine where his tricks are coming from. The tools for this include planning, reconstructing the original four hands and determining how to play certain card combinations and analyzing the opponents' motives.
By observing every card in the context of reconstructing the hands, the information such as order of play of spot cards is available if needed. But most of your useful information is gleamed from an analysis of what did not happen.
Say, for example, you are defending a contract of 3N. Dummy has DAQJxx, but declarer has tackled a short suit and you are in. You know that declarer holds the DK. Your target number of tricks will be informed in part by that knowledge. THEN you recall that partner (or opponent) gave count in another suit and know that you can wait for your tricks or that you must cash out.


My database dramatically increased in size. Why?

Question: I found that my database, specifically the USERS tablespace, dramatically increased in size.
How can I find what DML operations are performing on the objects located in this tablespace?
Comment: @ipip Haven't yet. Now I am analyzing archived log files using Log Miner.
Comment: Do you have diagnostic pack licenses?
Comment: Have you identified the "guilty" objects yet?
Comment: Using logminer is a tedious job but should provide you with the correct insight.
Answer: The query below will show you an overview of the schemas, tablespaces and objects in your database and their respective sizes.

- Change the group by to decrease the level of detail (you might want to see if the size is being caused by tables, indexes or other objects first)
- Add a where clause to only list the schema/tablespace/object_type you want to investigate.
select
  owner SCHEMA,
  tablespace_name TABLESPACE,
  segment_type OBJECT_TYPE,
  segment_name OBJECT_NAME,
  round((sum(bytes)/1024/1024), 3) MB
from dba_segments
group by owner, tablespace_name, segment_type, segment_name
order by owner, tablespace_name, MB desc;

It does not show you what DML is causing it, but it already shows you what objects are causing it. You can then go trough the query history in Enterprise Manager to find queries that work with these problematic objects.
In Enterprise Manager, go to the performance tab, and at the bottom select "Search SQL". Then search for queries with, for example, the large table in their "SQL text". Like this, for example: %large_table_name%
Good luck!
Answer: Another check I would recommend is find out which users have a quota for the USERS tablespace.  Also check who has UNLIMITED TABLESPACE system privilege.  If you find any account with the UNLIMITED TABLESPACE privilege, unless it is the DBA's account, remove it and provide specific quotas to tablespaces based on need (and reject any "gee, would be nice if I had that").  And to prevent this sudden size increase in the future, insure everyone who can write to USERS has a quota limit.  The USERS tablespace is usually used to provide a place for devs or others in case they need to create their own objects.  And it is also subject to abuse ("Gee, I can't import a couple of million rows?  /whine  I didn't know it would break something!").  And don't be generous with quotas, as most folks won't use what you give them, except for the few problem children (those who think ever-expanding hard drive space exists).  From what you have written, these protections were not in place, and you have a wild child on the loose in your DB.


Applying l'Hôpital's Rule to NDSolve with Piecewise Function

Question: OK, so I've been working on this problem for over a week and it's driving me crazy.
I'm trying to solve a system of two differential equations in $x(t)$ and $y(t)$ using a "time-elimination method," such that $\tfrac{d x}{d t}/\tfrac{d y}{d t}=\tfrac{dx}{dy}$ reduces the system to a single differential equation in $x(y)$.  The tricky part is that the initial condition needs to be defined at the steady state of the system $\{x_{ss},y_{ss}\}$, where $x'(t)=y'(t)=0$.  The slope at this point is undefined since $dx/dy=0/0$ as $y\to y_{ss}$ by construction.
I've seen two common ways of dealing with this.  The first involves finding a kind of approximation to the solution by slightly perturbing the correct initial condition so that $x'(y)$ is always well defined.  For example, suppose the system is defined as:
y0 = 1; yss = 10;
xdot = 2*x[t]-y[t];
ydot = (.01 + .1*x[t])*(Log[yss/y[t]]);

We can find a solution using:
xdoty[y_] = (xdot/ydot) /. {x[t] -> x[y], y[t] -> y};
NDSolve[{x'[y] == xdoty[y], x[yss - .001] == xss}, x, {y, y0, yss - .001}];

which yields the following results for $x(t)$ (purple) and $y(t)$ (blue):

Notice that the solution for $y(t)$ "blows up" as it comes within .001 of $y_{ss}$.
The second, more accurate approach is to overcome the ill-defined slope at the steady state via an application of l'Hôpital's rule.
In Mathematica, I usually deal with this by passing a Piecewise function to NDSolve, e.g.:
NDSolve[{x'[y]==Piecewise[{{xdoty[y],y<yss},{xdotyss,y==yss}}],x[yss]==xss},x,{y,y0,yss}]

where xdotyss is $x'(y_{ss})$ (a single scalar value) calculated after the application of l'Hôpital's rule.  This yields the following results for the system:

where both $x(t)$ and $y(t)$ are well-behaved throughout.
The problem I am having is that this approach does not always seem to work well.  Particularly, for some differential systems I can get the first "perturbation" method to give me approximately correct looking results, but the second "l'Hôpital method" always gives me the following error:

NDSolve::ndsz: At y == yss, step size is effectively zero; singularity or stiff system suspected.

Given that the first approach causes no errors, and the second approach is using the same differential equations to derive the value of the slope at that single point, shouldn't this always be a viable approach?  I can't think of what would be causing the system to suddenly become "stiff."
Any ideas?
Comment: Some of the variables don't seem to be defined. When I run the code for example, xss doesn't seem to be defined. Please try including a complete example.
Comment: `xss` is just the value of `x[t]` that sets `xdot=0` after substituting in `yss` for y[t].  I didn't include all the steps in the sample above, because it was not actually demonstrating the problem I was experiencing in another context.
Answer: Well, I guess I just needed one more day to work through the problem.  Apparently using the Piecewise function as I outlined above does work generally.  My issue with getting the ndsz "stiffness" error above apparently had something to do with precision, as changing all of my parameters to infinite precision forms (e.g. a=7/10 instead of a=0.7) allowed NDSolve to complete without any problems.  Hooray!  I hope someone else might find this useful.  In any case, I'm very grateful to anyone who took a moment to look at the question and give it a thought.  Cheers!


How can I tell which end of a wire will have a higher potential?

Question: I have the following setup:
<code>A <---- wire ----> B
</code>
$V_b - V_a = \Delta v = \text{a positive value}$
I have two questions:

Which end of the wire has a higher potential?
What is the direction of the electric field inside the wire?
Answer: From the given information that $V_b-V_a$ is positive, we know that $V_b>V_a$. The word "potential" means simply $V$, so point B is at a higher potential than point A.
Once you know that, you can go and remind yourself of the relationship between electric field and potential (no doubt it's in your textbook). That'll give you the answer to your second question.
Answer: Obviously $V_b$ is at a higher potential as Ted already answered. The relation between field and potential is simple.
$\vec E = - \vec \nabla V$
In this one dimensional case it is
$\vec E = - \frac {dV}{dx} \hat x $ where $\hat x$ is the unit vector along the positive x direction. So you see the field is in the $- x$ direction i.e. along $\vec {BA}$


How does a printshop print large solid blocks of colour

Question: For example: a 1.8m banner with a solid red background and white text. How would a printshop go about printing this? Surely they don't use a liter of red ink.
Answer: Screen printing to a vinyl substrate would be your best bet for this size of job.
Let's say your banner is 1.8m long by 0.6m wide. That gives us a surface area of 1.8m2 or 1,080,000mm2. If the entire banner is printed with red ink using the screen printing process then the thickness of ink might be, say, 15 microns (0.015mm). That gives us a total ink volume of 16,200mm3, or about 0.016 litre.
The screen print process typically lays down a thicker film of ink than other processes, so it is well suited to large solid blocks of colour.
Answer: You can go that route, but over-saturation of the substrate is a major issue when blanketing it with that much color. In addition, if the banner is being printed with inkjet, then successfully moving something that large and saturated to the drying rack carries risks as well that all lead back to reprinting. It's not impossible, I've done it lots of times, but it's not easy either.
If the design is simple enough, however, look into a creating a vinyl banner; red canvas with white lettering. Your sign shop will thank you.


Why can't you have multiple instances of Synaptic?

Question: I  would just like to know the reason.
Answer: Synaptic is just a graphical front-end to APT (Debian's package manager: Advanced Packaging Tool).
APT automatically locks one of a few special files (/var/lib/dpkg/lock among others) as it runs any operation. It is theoretically possible to programme APT to allow for concurrent processes to modify the package database. However, in practise, it is difficult to do so without risking corruption. Since most users don't need to use the packaging tool in this way, the developers have decided to disallow concurrency by implementing a lock.
If you want to install several packages at once, you can do this by ticking all of those packages in Synaptic, or listing them on the command-line, like this:
sudo apt-get install package1 package2 package3
Comment: If you look at the RPM based distributions, you see the same behavior if you try to run concurrent rpm operations.
Answer: You can run multiple instances of Synaptic. But only one of them can have administrative access. That's to prevent simultaneous modifications of the package databases, which could easily lead to them being corrupted.
You can run any number of instances of Synaptic with read-only access by typing synaptic at a command prompt.
Answer: Basically: Synaptic is working at very low level for installing/configuring software. Having two instances working at the same time, changing settings and stuff, would most probably lead to corrupted software, with unusable features - and if it is about system software, it could render your OS unusable.
Then Synaptic just can't be launched twice at the same time, to prevent such problems.
You could see it as a "security feature" ;-)


Express mode in lift

Question: In some lifts, if we press and hold the close door button, it acts like pass button and doesn't opens the doors in intermediate floors if some one gives lift request from intermediate floors. Does it really an express mode or is it a fault. If we consider establishing lift, is it good to request for this feature?
Answer: Hurray - a non website - non desktop - non mobile, UX question!
If pressing and holding the close door button is the only trigger, and everyone found out about this shortcut, then it could result in bedlam with lots of unhappy users and lots of ab-users! The only person it will ever benefit is the person who travels between the bottom and the top floor - so its a kind of penthouse apartment privilege.
One other situation where it might be relevant is in a tourist lift in a building of interest where an attendant controls the lift and wants to ensure it doesn't stop at intermediate floors but goes straight up or down.
Another situation is a goods or service usage where bulky deliveries or laundry trolleys should go directly to required floor without inconveniencing people on intermediate floors with having to get in a lift with dirty laundry etc.
However, in each of these cases I seriously doubt this intended to be achieved via the shortcut mechanism of 'press and hold' the close button as the sole controller for that purpose - it's usually a key setting for individual service - so you would insert key and turn, then select floor - and the pressing and holding of the close door button may or may not be a part of it.
I suppose that's not to say that as a cheaper fitted option in some smaller buildings, the key switch can be left out but the close door button shortcut is left in. Maybe that's a fault, maybe deliberate - but is it intended usage by the lift manufacturers? I doubt it
So in summary - it's a useful thing but best if enabled by a key to switch mode, otherwise it's too open to abuse - which is why it needs a key as well. Consider who is going to know about the shortcut. Who benefits from the option, and who does not. Consider the users of the lift - are there service/trade users who will benefit. How busy is it on the intermediate floors. What happens in an emergency or peak hours.
Comment: Also hurray for a non desktop / mobile question.  Nowadays I'd suggest that having to use a key to override is a bit old fashioned.  Using a plastic card would be better as lost cards could be cancelled.
Answer: For a moment, let's just assume that it would be a desirable feature. Then the way that it is implement would definitly lack usability (weak affordance): as it is uncommon, the user needs to see an explicit sign that this lift can do this, and how the user can activate this. A label "hold down for express mode" would be a first step.
But then, I agree with Roger that it would be abused (that is, everybody (indivually) would want to go the fastest way possible, even if that means that everybody (globally) will take more time. See the Prisoner's dilemma.)
That's why I'd rather suggest that the automatic floor routing algorithm should be improved. The used algorithms range from really simple (in-lift commands have higher priority to outside commands) to standard (try to avoid changing direction) to advanced (try to minimize waiting time). But I have never seen a lift that detects when it is full and, thus, doesn't open the doors if nobody wants to get out.
A typical usability approach would be to go out and interview people that use the lift. What annoys them? Why? And only then: how could this be improved?

Express mode in lift


When To Dry Hop?

Question: I'm working with a recipe for a black ale (Cascadian Dark Ale) and it's telling me to dry hop 0.25 oz Warrior hops and 0.5 oz Cascade hops right after transferring to the carboy.  I had read that the best time to dry hop was after some of the fermentation had already taken place.  Is this timing special to the Cascadian dark?  What are the consequences of dry hopping this early in the fermentation?  Should I adjust the recipe?
Answer: There is nothing special about the style.  The best time to dry hop is … immediately before serving, ultimately.  Hops fade as a function of time, so minimizing the time between introduction and consumption is key.  E.g., if you want to age/condition your beer for 3 weeks post-primary before serving, and want to dry hop for one week, you should introduce the dry hops after 2 weeks.
Answer: The instruction to add hops to the carboy is a little unusual, but if you think about it, its kind of like a post-chilling whirlpool addition, so its not totally unheard of. You will loose some delicate aroma through off-gassing during fermentation, and since its only .75oz total, I doubt this addition will contribute much to the finished beer.
Some folks advocate adding dry hops at the tail end of fermentation, but before its totally done. The idea being that the last bits of C02 from the fermentation will help drive out the oxygen introduced with the dry hops. I suppose this is more important with loose leaf hops as opposed to vacuum-sealed pellets. You will loose a touch of dry hop character from adding them early like this, but the trade off is that less oxygen post-fermentation means that the beer tastes better for longer.
Answer: Aroma = molecules in the air detected by olfactory neurons in your nose, so it makes sense that if your yeast are producing lots of CO2, the gas will carry away some of your nice aroma molecules and reduce the effectiveness of the dry hop, which is really about maximizing that hop aroma. In my experience, 2-4 days before bottling/kegging seems to work well, a week max. The last IPA recipe I did recommended fermenting a week then dry hopping for 2 weeks so I tried it. It still has a big hop aroma, but I think it resulted in a bit less hop aroma than the 2-4 day dry hop I've done before.
Answer: my experience has been that 3-5 days total is plenty for dry hopping, post fermentation and as close to kegging/bottling as possible.
Comment: Please, post an answer in a form that makes sense on it's own, even if other answers are deleted and comments purged.
Comment: -which is why I followed the "agree with" statement immediately by the actual point I was agreeing with :)  Regardless, will try to remember for future reference

When To Dry Hop?


100 year old hand painted backdrops - How to gently clean?

Question: We have just taken possession of a group of hand painted back drops that are somewhere between 70 and 100 years old.  They hung in a neighboring Masonic Lodge for all that time.  Do I dare try to clean these or should I just hang them in their new location and enjoy them?  There are also some small rips or tears is some of them. (No holes).  What is the best method to patch these.  Each of the 5 painted canvases is approx. 12 feet tall x 20 feet wide.  Any and all suggestions are welcomed and appreciated.
Answer: Conservation of old materials is a specialist area, if in doubt do nothing. Your local museum might be able to advise. At a guess: keep out of bright sunlight, control humidity, don't fold (perhaps don't even roll up). Remember Hippocrates: first do no harm.
Comment: No, it fits with the idea of handling photographic equipment of all sorts. So, I think it's on topic.
Answer: Remember that light has an adverse effect on many materials -- that's why museums often prohibit flash photography. Keeping your backdrops out of the sun will help, but if you're planning on using them in photo shoots, be aware of the damage that repeated exposure to speedlights and other very bright light sources could cause to both the paints and the fabric.


Apple USB to Ethernet failed to work

Question: I bought a USB to Ethernet adapter from Apple, and I downloaded a lot things this afternoon. After dinner, both my retina MacBook Pro and the adapter felt very hot, so I unplugged it. Now the MacBook Pro seems to be frozen and I have to hold the power button for several second to force shut it down. And later that day, the adapter refused to work.
Here is the log in my /var/log/system.log:
Oct 25 21:38:08 localhost kernel[0]: AppleUSBEthernet: Ethernet address 20:9a:dd:41:24:89
Oct 25 21:38:10 localhost kernel[0]: AppleUSBEthernet::doReenumerateDevice - Link down, Device 4f764100
Oct 25 21:38:10 localhost kernel[0]: ifnet_detach_final: Waiting for IO references on en2 interface to be released

Any idea? Is my adapter or the kext is broken?
Answer: This can be fixed adding/removing the device from the Network System Preference Pane.

Apple USB to Ethernet failed to work


What was so surprising about accelerating cosmological expansion?

Question: The 2011 Nobel Prize in Physics, as far as I understand, concerns the expanding universe -- galaxies moving away from each other at ever increasing speed (that's what I think I read in newspapers). Now, the idea of expanding universe is not new. What is the novelty in this study? What was unexpected in it?
Comment: @ganzewoort No, it's not trivial to Google most questions here.  The point is that you try to learn something first, and then when you find it's difficult to find a good resource or you don't understand what you've found, you ask  a question.  In this case, the specific question you asked, involving what was new in the findings of the expanding universe, is indeed trivial to google.  (It is that the expansion is accelerating.)  This information is in almost any press release, news story, blog  post, wikipedia, etc.
Comment: The research that led to this Nobel prize should certainly spark many good questions.  However, "What was so special about this finding?" isn't an interesting one.
Comment: It's trivial to Google this.
Comment: @Mark I think there's a valid discussion to be had about if this fits the scope of Physics SE.  After all, others Googling the topic may find themselves here.
Comment: It is even more trivial to google questions in classical physics, quantum mechanics and relativity. Why have stackexchange then?
Comment: @Mark, I disagree, it is not trivial to google the following aspect of the question: If, as claimed, the expansion of universe is indeed accelerating then we may wonder why do we need neutrinos to claim speed of light can be overcome. If I don't understand the acceleration properly then correct me.
Comment: @ganze I don't see how that's disagreeing with me.  It's asking a completely different question that you did not mention at all originally.
Comment: @Mark, OK, my fault but isn't it something that pops up immediately when hearing about ever increasing rate of expansion? I'd be interested to hear your take on that.
Comment: I made some edits that hopefully will improve the question significantly without changing the main point.
Comment: Maybe you forget the Nobel Prize is often awarded for discoveries made decades ago. In these day, their discovery is probably part of textbooks so you don't find them groundbreaking.
Answer: This taken from my Web page at
http://www.astro.ucla.edu/~wright/cosmo_constant.html
Assuming one virtual particle per Compton wavelength cubed gives a vacuum energy
density scaling like $M_{particle}^4$.
For the highest reasonable elementary particle mass, the Planck mass of 20 $\mu$g, this density is more than $10^{91}$ gm/cc. So there must be a suppression mechanism at work now that reduces the vacuum energy density by at least 120 orders of magnitude.
A Bayesian Argument:
We don't know what this suppression mechanism is, but it seems reasonable that suppression by 122 orders of magnitude, which would make the effect of the vacuum energy density on the Universe negligible, is just as probable as suppression by 120 orders of magnitude. And 124, 126, 128 etc. orders of magnitude should all be just as probable as well, and all give a negligible effect on the Universe. On the other hand suppressions by 118, 116, 114, etc. orders of magnitude are ruled out by the data. Unless there are data to rule out suppression factors of 122, 124, etc. orders of magnitude then the most probable value of the vacuum energy density is zero.
So the existence of a "small" but noticeable vacuum energy density is very surprising.
Answer: I'm not sure that the accelerating expansion was so surprising. If the universe is expanding there are only three possibilities, it's expanding at a constant rate, accelerating or decelerating!
The prize was for the breakthrough observations and careful experimental technique of correcting for the difference in brightness of supernovae to be able to make the measurements.
This discovery didn't answer the more interesting questions of how and why it's accelerating.
Comment: I would again submit that the really interesting claim is that the universe is expanding at ever increasing speed. Has this fact really been established by these or perhaps earlier studies? I don't think accelerating expansion is unsurprising as would be the uniform or decelerating expansion.
Comment: @ganzewoort: I think your comment's first sentence answers your question. We all accept there was a big explosion, and the pieces are still flying outward. But one would think they'd be gradually slowing down under the influence of gravity. They're not. That's surprising. Something is still pushing them out even faster. It's got a name (cosmological constant), but *what is it*?
Answer: A decade or two ago, there was uncertainty of the order of 50% about the age of the universe, and its composition. It could have been 8 billion years old, it could have been 20 billion years old. The reason for the uncertainty was that the models of the global universe weren't accurate. This discovery made all the pieces fit together for the first time. It has since been verified by precision CMB measurements, so that the supernovas are definitely good standard candles for determining distances to far away galaxies.
By estimating the velocities of the individual galaxies in large clusters, astronomers could estimate how much dark matter they contain. These types of observations gave the most inclusive estimate for the total matter in the universe, visible ad dark. Relative to the amount required to close the universe, the initial estimate of the density, based on visible matter, was 4% of the critical density. It went up to about 10% when dark-haloes inferred from galactic rotation curves were included, and finally up to about 30% when dark matter in galaxy clusters was included.
But inflationary cosmology predicted 100% with no wiggle room. It was simply inconceivable that the universe could have been so fine-tuned to have 30 percent critical density today , because the fine tuning gets ever finer as you go back in time. So physicists kept pressing the astronomers to come up with the remaining 70%, and they kept on saying they couldn't do it, and this was a source of tension for nearly twenty years.
The measurement of accelerated expansion immediately gave a cosmological constant which would explain the missing 70%, and this gave a correct model, consistent both with itself and with inflation, for the first time. The COBE and WMAP observations (which got the Nobel too) then allowed for the detailed standard cosmological model to emerge.
Comment: So, then, what are the current velocities of the galaxies moving away from each other and what is the change of these velocities per unit time?
Comment: @ganzewoort: Galaxies near us move away at a rate called the Hubble constant H, which is 1 over 14 billion light years. So they move away near us at a fraction of the speed of light equal to their distance over 14 billion light years, give or take 5%. Their current acceleration (meaning, not what we would see, but extrapolated to the present moment) is also proportional to the distance, with a proportionality constant equal to qH2, where q is the acceleration parameter, about .7, so about 1/280 billion billion light years squared, or a velocity e-folding time ~20 billion years (but it changes)


Which Enzymes are Responsible for the Biodegradation of Noladin Ether?

Question: Which enzymes degrade the CB1-specific endogenous cannabinoid 2-arachidonyl glyceryl ether? (Noladin ether)
Answer: Noladin is an endocannabinoid. The best-characterised members of this family of molecules are Arachidonoylethanolamine (AEA; anandamide) and 2-arachidonoylglycerol (2-AG). The degradation of these endocannabinoids is reviewed in:

Pamplona, FA et al. (2012) Psychopharmacology of the endocannabinoids: far beyond anandamide. Journal of Psychopharmacology 26:7-22

These endocannabinoids are inactivated via a reuptake system that is present in both neuronal and glial cells, although the protein responsible has apparently not been identified.
AEA is then metabolised to arachidonic acid and ethanolamine by fatty acid amide hydrolase, while 2-AG is converted to arachidonic acid and glycerol by monoacylglycerol lipase.
Because of its ether linkage, noladin cannot be a substrate for either of these enzymes. However the review also describes other possible pathways of endocannabinoid metabolism involving oxidation by cyclooxygenases, lipoxygenases and P450 cytochromes. These are the best candidates for the further metabolism of noladin, but there is apparently no direct evidence for this.


English Horn Etymology

Question: Why is the English Horn called a horn when it is a woodwind instrument, basically a lower oboe?
When compared to other horns, such as the French Horn and the Flugelhorn, it seems to be a misnomer.
Comment: Related - https://music.stackexchange.com/questions/53263/why-does-the-english-horn-have-a-french-name-and-the-french-horn-an-english-nam
Answer: Interestingly enough, the English Horn is commonly known by the French term 'cor anglais', but in fact originated in Germany! To make matters worse, the French Horn is a descendant of the English hunting horn.
The term 'horn' has had varying meanings throughout history and genre. At the most basic level, it simply refers to the cylindrical shape of an animal's horn, which would be hollowed out and turned into an instrument like the shofar. (As classified by the Hornbostel-Sachs system of musical instrument classification, all modern brass instruments are cousins or descendants of this type of instrument.) This definition was then applied to other instruments that made use of a cylindrical horn-shaped bell, whether they were "trumpets" or not.
In present-day popular music, the vernacular term has generally expanded to include all wind instruments, including modern woodwinds like the saxophone. (Basically, if the leader says "horns!" and you're not singing, playing keyboard, or holding drumsticks or a type of guitar, then they're talking to you.)
So, 'horn' on its own is not exclusive to brass instruments. However, the reason for the english horn, or cor anglais being referred to as such seems to stem from the fact that despite it being a type of tenor oboe with a bulb bell, it was similar enough to another instrument, the oboe da caccia, or "hunting horn" in Italian, that had a plainly flared bell. The name stuck when that instrument fell into disuse.
So yes, it is a bit of a misnomer! It would make much more sense to have it be part of the oboe family, as the fingerings are similar and most players of the english horn began as oboe players.
Answer: The best explanation I have heard was that the term "English" does not really refer to originating from a country, but rather angled/curved/spun as in "putting English on a ball."  This was from an expert speaker at an International Double Read Society convention, so YMMV.
[As an interesting aside, one of the answers to the referenced question says 'from Fr. anglé "angled," which is similar to Anglais "English."']
Comment: That is an interesting insight.
Answer: There is another variation, called the oboe d'amore ("oboe of love" in Italian), which is pitched "mezzo-soprano" between the oboe and the English horn. There is a modern oboe d'amore, but it is more often found in its Baroque version in contemporary Baroque music ensembles and early music groups. Some people conjecture that its modern name is a pun based on the name  "Oboe of the Moors," meaning an instrument descended from Middle-Eastern Arabs that lived in Spain up until mediaeval times. If this is true, then the oboe d'amore would have the same ancestors as the Turkish zurna, another double-reed wooden instrument with a wide trumpet-like bell that comes down to us from antiquity. The European version, from Renaissance times, was called the shawm.

English Horn Etymology


How many (and what) things have I failed to do if I get into a fight?

Question: Basically every answer I've ever read that involves a "real-world" situation begins with "If you got into a fight, your training already failed you". I know - I gave a couple of those answers.
So, I'm in a fight. What have I failed to do?
Answer: Most likely, you haven't

been careful of your situation and mindful of your surroundings,
avoided dangerous places or people, and/or
worked hard or smart enough to defuse and de-escalate situations of rising emotions, tensions, and territoriality (either your own or of those around you).

Now, a lot of "you failed to do X!" discussions seem to assume that perfect situational awareness and response mechanisms are always feasible. That borders on magical/Utopian thinking--in the same class as "true black belts can block any punch!!" Haha--no. Only on television. It's unrealistic to assume that everyone can always be in only safe places, only associate with calm/respectful people, or at all times be observing and managing their situations with perfect aplomb.
But let's assume you've taken "reasonable precautions" about where you are and who you're with, that you have "good" (though not Sherlockian) situational awareness, and yet you still find yourself near to or in a fight. What did you not do? I'd wager:
You didn't back down.
People generally don't like to appear weak or submissive. That's what "losers" are, right? If someone "gets in your face" or claims this is their territory, you "stand your ground," right? Maybe even "take the fight to them." After all, you're a trained martial artist! You have every right to be here. Dammit, you're in The Right! They should back down. Next thing you know, you're in a fight. Getting hit. Or shot.
Because even though you were reasonably careful and aware initially--especially of your external surroundings--you weren't sufficiently aware of your own internal responses. Your anger. Your ego. Your territoriality.
A lot of martial arts schools teach "how to fight." How many teach "how to avoid a fight" or how to calm down a situation"? Not so many. In theory, many teach a little Zen-y mumbo jumbo, or do a little meditation. Not many do much work on that moment of escalation, where everyone's emotions and territoriality are flaring. Not many teach you how to not fight, how to back down, to submit gracefully. That's probably why you're in that fight!
Answer: I think it really just comes down to one thing. If you made a mistake, the mistake is that you were looking for a fight. It's an understandable tendency among martial artists, especially those that train for the "mean streets," after all; what's the point of training to fight and defend yourself in the mean streets if you don't ever actually use your training?
If we're talking about a fight that happened, only someone who was there can for sure know whether the fight was actually avoidable. Usually, however, we're talking about a hypothetical, and in this hypothetical, martial artists want to "test" their fight theory. If you think about hypothetical situations like that, that could create a tendency to actually go for the fight when there was an option available to avoid it. So constantly reminding ourselves (I really think it's more for personal benefit than for anyone else's) that you always want to avoid the fight will create that tendency when a potential fight situation comes up.
So assuming you weren't looking for a fight, and it happened anyway, any mistakes are of the "hindsight is 20/20" variety. There probably was something you could have done, like not be where the fight happened, even if that meant skipping your friend's birthday party, but then why would you think about the potential of a fight breaking out unless you were looking for a fight?
There's obviously a bunch of common fight avoidance strategies:

Cross the street to the other side if you see someone suspicious/drunk/on drugs
Don't drink alcohol unless around people you know and trust
Walk with purpose, don't wander aimlessly
Don't be alone
Don't get into arguments
Don't go to pubs/clubs/etc where fights commonly happen
Don't go anywhere that they feel a need to have security and check everyone for weapons
Move to a new apartment/suite/etc if you have regular problems with your roommate/neighbour
Don't take a job that puts you somewhere that you might have to fight (server, bouncer, nurse)

But really those are only guidelines that will help you avoid most, but not all fights. What if there's only a sidewalk on one side of the street and there's heavy traffic? What if you just want to enjoy one of the few sunny days outside? What if your job ends late and walking alone is your only option? What if you have to take any job you can get, or else be on the street ('cause that'll definitely increase your chance of getting in a fight)? There's tons of what-ifs, and they're perfectly legitimate as long as you're not looking for a fight. If you were looking for a fight, it's just an excuse to be in a situation where you can test your skills.
If you are someone who's itching for a fight, take up a competitive, full-contact, full-resistance style. Either train MMA, or one or more common MMA feeder styles. You'll get your desire to fight worked out in competition, so when it comes to "real life" you're satisfied. If you're generally conflict-averse, remain conflict-averse and you'll be fine.
Another way you can look at it is like this. If you had no training of any kind, what would you have done to avoid the fight? Did you do it? If yes, there's nothing else you could have done. If no, that was your mistake.
Answer: To be a little bit Zen:

So, I'm in a fight. What have I failed to do?

You've failed to end the fight.
There could be nothing that you've failed to do. People are like animals, one day you can end up in a fight that you had nothing to do with. To absolutely remove all chances of having a fight you would have to live your life in a vastly different way, eschewing human contact altogether, and you would probably still end up fighting - fighting the wild squirrels/monkeys/whatever to get your food.

"If you got into a fight, your training already failed you"

That sort of answer is usually proffered by pontificating fools (they do exist, even in MA circles). Theory around de-escalating fights, managing crowds, soothing people's feelings, etc. is add-on humanity type stuff that some instructors teach and isn't strictly included in any martial art. Nor should it have to be - you can go to other classes to learn that stuff. Techniques that work for one person in one situation may fail miserably when used by someone else some other time. The quoted statement makes the very large assumption that you could have or should have walked away. Situational awareness (which is something that is learnt from martial arts) and experience will sometimes say that you should stay and fight (even if momentarily).
Comment: If the only reason you're fighting is because you thought you could take the guy, your training *has* failed you.
Comment: True, "add-on humanity type stuff" isn't strictly martial. But beyond Wacka Wocka Fu, many martial arts schools promise to teach "self-defense." It's a stickier wicket. If you aren't cognizant of human behaviors, you're not "situationally aware" of anything interesting. And even ace fighters who can't manage human interactions and conflicts, can't really defend themselves in the real world, where low-skill weapons abound. If martial schools are going to teach any genuine "self defense," then "add-on humanity type stuff" isn't so very optional.
Comment: I have found that the more useless the martial arts school, the bigger the emphasis is on running away rather than fighting. That being said, the best thing to do to avoid a fight is to not go to places where idiots hang out. And don't wear your TapOut shirt. Those things are douchebag magnets.
Comment: I will agree with Robin on that point
Answer: Maybe you failed to do everything... maybe you failed to do nothing.  It's one of those quotes that may make an old master seem wise in a movie, but it's basically just a noble sentiment that falls apart on examination.
Sure, perhaps you're out wandering in the wrong section of town... or didn't cross the street when you should have... or you're in the wrong night club.  Maybe when confronted your ego compelled you to try to save face.  Those sorts of things may indicate that you weren't being proactive in keeping yourself safe.
On the other hand, what about home invasions?  predatory criminals?  or predatory government in some parts of the world?  Violent, mentally ill people?  Like it or not, random, no-fault-of-your-own violence occurs.  Short of locking yourself into a cold war era bunker (and even that has its limits), you can't be guaranteed of anything.  That is why we train.
And that of course ignores the cases where the violence isn't meant to be avoided.  For example, a police officer purposely engaging in it to protect others.
Answer: Your training hasn't failed you if you're not training conflict avoidance/resolution in your dojo.  Rather, your lack of training has failed you.
You have to specifically train how to read body language, detect warning signals, and recognize potentially dangerous situations.  These skills are usually relegated to a weekend seminar, if taught at all.  When we hit the mat, we're kicking and punching, not talking and thinking our way out of conflict.
If you're not receiving this kind of training in your dojo, you're going to have to devote time to it out of class.  If you'd like to learn more about how to recognize dangerous situations and how best to avoid them, read The Gift of Fear by Gavin DeBecker.
Answer: Sometimes you cross paths with a douchebag. The reason why martial arts and self-defense classes actually teach you how to hurt people, and not just how to run away, is because some situations are unavoidable.
I have found that the more useless the martial arts school, the bigger the emphasis is on running away rather than fighting. That being said, the best thing to do to avoid a fight is to not go to places where idiots hang out. And don't wear your TapOut shirt. Those things are douchebag magnets.
Comment: I found out that the more useless the martial arts school, the bigger the emphasis is on fighting rather than running away. It's all down to personal experience I guess... ^_~
Comment: I don't know man. I produced 5 students who went on to win national titles. I had a very simple rule : start nothing; finish everything. It seemed to work rather well.
Answer: After spending years in Martial Arts , somethings get clearer to you. First of all , I am in MA for 12 years in distinct disciplines like Kick Boxing , Ninjutsu , Wing Tsun and BJJ. I am happy to combine these and Kali/Escrima. For those years , I took many blows during both training and competitions. Still taking. But in real-life , I have never been a tempered man. It is really really hard to drag me to a fight. Because , I accept the fact that , If I start fighting , I can die or I can kill. So if I am going to fight on street , it must be for a reason worth killing and dying. When I get angry to a person , I always imagine we fought and accidentally I killed him or broke his limb. He might loose a leg or arm/hand forever if i break it badly. I concentrate on aftermath. Do I feel guilty ? Was there any other option ? Did my ego cause this?
As a Muslim , when i die , i will be questioned for killing this guy. Do i have an ultimate reason? If i had another option and not taken it , how am i going to explain why i didn't?
If you think that way , you will never take that dangerous path to home. You will never fight with a person because he talked you badly or insulted you. I am a strict Kant moralist (Immanuel Kant). Results are not important for me. Intentions are. If there is even a slightest chance that I might kill someone during a fight , that means I took that risk by starting a fight. Taking that risk , means responsibility. The degree of necessity is the distinction between me and a murderer. So if the trouble found me and I have nowhere to escape , I fight with all I got. This is also an important key to win fights. If you fight for weak reasons , you will be weak.
Mostly, your ego puts you into a fight. A guy says something , you don't back off. Because your ego dictates you. Even if you are the right side , saying okay and backing off won't change anything for you or for rest of the world.
And all these ideas tend to shape with your training. More training means more sense of responsibility for a person who is conscious. Of course if you don't have a teacher who trains you like an attack dog rather than a human being.
Answer: "If you got into a fight, your training already failed you". It's easy to object to this sentence, because obviously it isn't true and can't be. As other people's answers already pointed out, you may end up in a fight without any fault on your part. But still there is also some wisdom in this statement.
The meaning behind this assertion is that your training aims at building up your confidence, which translates into

having a confident demeanor, a body-language which reflects self-assurance in a non-aggressive way
being able to remain calm in situations where you are confronted with aggressiveness
being polite and humble, so you don't unnecessarily provoke negative reactions in others

These qualities will prevent most situations where you might end up in a physical altercation. A fight is a situation where a lot of things already went wrong. Even in the animal world, fights over territory or females are often avoided, when the balance of power can be evaluated beforehand. That's the meaning of this statement and of course there can be situations where you have to fight, where you can't back down, when you have to protect someone for example or when a situation gets out of hand without you being involved in the escalation.
You have also to keep in mind that this kind of assertion probably comes from an Asian background and is not meant to be bullet-proof true from a purely logical point of view. It is a saying that aims to convey a certain wisdom and mindset not to be clung to in every situation.


Question-shaping pop-up

Question: I am picturing here a system wherein if you ask a question without specifying some key information that is almost certainly required to answer the question correctly, a pop-up (just like the "please consider adding a comment if you think this post can be improved"; not a pop-up pop-up) will alert you to this fact and perhaps even suggest appropriate tags.  Maybe this is better explained by example:
Stack Overflow example
A "How do I make a regex to find this ..." question that doesn't mention the environment in which it will be used (Perl, POSIX, Java, .Net, etc. all have different "regex flavors" and can behave very differently).  The system will detect the use of a keyword or tag ("regex") but the absence of a handful of critically important keywords ("Perl", "POSIX", "Java"...) anywhere in the title, question, or tags and will alert the user to this fact.  It shouldn't by any means block the user from submitting the question without this information; it should just be a gentle reminder.
Super User example
"How do I format a disk" but no mention of which OS they're using.  "Format" is detected, but not any of "Linux", "Windows", "OS X", etc.  Same principle.

Architecturally I'd imagine this being just a bit more meta data attached to tags, called "crucial information" or something.
Answer: I am not going to support this due to it potentialy becoming a lot of extra work on the site admins/designers.
Answer: This sounds like a whole lot of work to implement something which is going to have a lot of AI holes in it, when the best option is still going to be a user commenting on the question and saying "you need to include X, Y, and Z."

Question-shaping pop-up


What is the best way to level transmutation in Everquest 2 if you got a late start

Question: I've been playing EverQuest 2 Extended with my after quitting WoW several months ago.  Not used to the tradeskill system in EQ we didn't realize you started with the transmutation skill instead of having to learn it, so I didn't start transmuting anything until I hit level 15.  Unfortunately, by then I'd gotten rid of most of my low level gear.  Low level mobs won't drop me items since they're grey, and finding rare mats to craft Mastercrafted quality items takes forever and since the highest level item I can make of the first tier is level 2, they rarely give skillups.  Is there a better way to do this? We're on bronze accounts so we can't use the broker or anything, and my limited bank slots are filling up with gear that I could disenchant if I could just get to X or Y or Z level transmutation.
Answer: Ok, I found a way that is at least, not as painful, though it's still not super fast.  The scholar type crafting professions (sage, artificing, and alchemy) can create skill learning items for various classes.  Skill items of at least expert level can be transmuted like Treasured or Mastercrafted items.  Unlike Mastercrafted items, these items can have levels other than X1 and X2.  This seems to be the only way to craft transmutable items high enough level to give a decent chance at skillups.
There's also a mount you can get from a crafting quest chain in Butcherblock Mountains that increases your transmutation skill by 9.
Answer: You can also visit a chronomage in one of the main cities and self-mentor back to a lower level, such as 5 or 10. You can then get transmutable drops again. I can't remember for sure if that option is available at any level or not until level 20, but if self-mentoring doesn't work you could have your friend create a new character for you to mentor down to.


What are the steps to simplify the following modulus expression?

Question: I have no clue how to do this exactly. Is there a systematic way of doing this or you just have to do it by trial and error?
$n^2 \equiv 9 \pmod {72}$
to $n \equiv a \pmod b$?
Answer: Note that $n^2\equiv 9 \pmod {72}$ is equivalent to
$$
(n-3)(n+3)\equiv 0 \pmod {72}
$$
So it is sufficient to solve the simultaneous congruences
$$
(n-3)(n+3)=0\pmod 8
$$
and
$$
(n-3)(n+3)\equiv 0 \pmod 9
$$
The second congruence is true iff $n$ is divisible by $3$, because then both $n-3$ and $n+3$ are divisible by $3$, so their product is divisible by $9$. If $n$ is not divisible by $3$, then neither $n-3$ nor $n+3$ is divisible by $3$, so their product isn't. Thus, $n\equiv 0 \mod 3$.
In the first congruence, we similarly obtain that $n$ must be odd. We claim that this is also sufficient. Indeed, since clearly $n-3$ and $n+3$ are both even, assume that they are both $2 \pmod 4$. This is clearly impossible because they have a difference of $6$. Thus, one of $n-3$ and $n+3$ must be divisible by $4$, and the other is even, so their product is $0 \pmod 8$. Then $n\equiv 1 \pmod 2$.
Then, the set of solutions is just all $n$ that satisfies $n\equiv 1\pmod 2$ and $n \equiv 0 \pmod 3$, which is equivalent to $n \equiv 3 \mod 6$.
Answer: $n^2\equiv9\pmod{72}$ iff $72\mid n^2-9$, i.e., iff $n^2-9=72k$ for some integer $k$. Then $n^2=72k+9$ is divisible by $9$ and hence by $3$. Since $3$ is prime, this implies that $3\mid n$, and we can write $n=3m$ for some integer $m$. Now we have $9m^2=72k+9$, or $m^2=8k+1$, i.e., $m^2\equiv1\pmod 8$. It's staightforward to verify that this congruence is satisfied precisely when $m$ is odd, say $m=2\ell+1$. Thus, the full set of solutions is given by $n=3m=3(2\ell+1)=6\ell+3$, which can be rewritten as the congruence $n\equiv3\pmod6$.
With more experience you would know that since $72=8\cdot9$, the congruence $n^2\equiv9\pmod{72}$ implies the congruences $n^2\equiv9\pmod8$ and $n^2\equiv9\pmod9$ and could start working with them immediately. (In fact $n^2\equiv9\pmod{72}$ is equivalent to the conjunction of $n^2\equiv9\pmod8$ and $n^2\equiv9\pmod9$, since $\gcd(8,9)=1$.)
Answer: The congruence forces $n$ to be divisible by $3$, so $n=3k$. Then $n^2\equiv 9\pmod{72}$ iff $9k^2\equiv 9\pmod{72}$ iff $k^2\equiv 1\pmod{8}$.
The solutions to this last congruence are $1$, $3$, $5$, $7$ (modulo $8$). This can be expressed more simply as $k\equiv 1\pmod{2}$. Then we get $n=3k\equiv 3\pmod{6}$.
Answer: In this case, since $\,9\,$ is a perfect integer square much smaller than $\,72\,$ , the beginning of the solution is pretty straightforward:
$$n^2=9\pmod{72}\Longrightarrow n=\pm 3\pmod {72}$$
But since $\,72\,$ is not a prime there may be other solutions, and in fact we also have, say
$$n^2=9\pmod{72}\Longrightarrow n=\pm 9\pmod{72}$$
Answer: Note that $72=8\cdot 9$ and that $n^2\equiv 9\pmod{72}$ implies (and is in fact equivalent to) $n^2\equiv 9\pmod 9$ and $n^2\equiv 9\pmod 8$.
The first simplifies to $n^2\equiv 0\pmod 9$, i.e. $3^2|n^2$. This is equivalent to $3|n$. The other equation simplifieds to $n^2 \equiv 1\pmod 8$. You may try these few cass by hand, but one should know this special property of the prime $2$:

The square of an even number is always $\equiv 0\pmod 4$
The square of an odd number is always $\equiv 1\pmod 8$

Thus  $n^2\equiv 9\pmod{72}$ is the same as $n\equiv 0\pmod 3$ and $n\equiv 1\pmod 2$, i.e. $$n\equiv 3\pmod 6.$$
Check: If $n=6k+3$, then $n^2=36 k^2+36 k + 9=36\cdot k(k+1)+9$. Since one od the numbers $k, k+1$ is even, $k(k+1)$ is even and $36k(k+1)$ is a multiple of $72$.
Answer: $n^2 = 72 M + 9 = 9(8M+1)$. Hence, $9 \vert n^2 \implies 3 \vert n$. Hence, $n = 3k$. This gives us that $k^2 = 8M+1 \implies k$ is odd (since any odd square is of the form $8k+1$ and even square is of the form $8k$ or $8k+4$). Hence, $$n = 3(2 \ell + 1) = 6 \ell + 3 \equiv 3 \pmod{6}$$


Can I stop iPhone apps from changing my Gmail status?

Question: I recently got the Mo+ GV iPhone app to replace talkatone and it's a thousand times better. The problem is is that when I'm logged in (It connects to GTalk/voice) my gmail status is changed to an annoying ad. something like "I'm using Mo+ get it now at blah blah", and I know a lot of other apps do this too. Is there a way to disable this from happening? (Its not in the app settings)
Answer: I'm going to assume that you mean this app: https://itunes.apple.com/us/app/phone-for-google-voice-talk/id541829441?mt=8 Since the app is free, it's reasonable to have ads. You could email the developer and ask for it to be removed in the next release.
Or, if you don't mind losing the Google Voice integration, you could go with Verbs ($1), which is an IM app.
Less reliable way to fix it: After signing in with Mo+ GV, sign into Gtalk from somewhere else (like your computer). I think only the most recent status will be displayed.
Insane way to fix it: Jailbreak your iPhone to disable code signing. Then, find the "I'm using Mo+…" string in the application's binary and change it to an empty string.
Answer: You can change it by clicking on the status symbol to the top right corner, then click on your email, then click "signature." You can type something else to show, but if you delete it entirely it reverts to that terrible default message to your contacts. I hate Mo+.


Why can $\beta$ not be linearly proportional to $T$, that is $\beta = constant \times T$?

Question: $\beta$ in statistical mechanics is equal to $\frac{1}{k_BT}$ in in thermodynamics, but I do not understand why $\beta\propto T^{-1}$ instead of, say,  $\beta\propto T$?
Answer: Because by convention, we want to write $\beta$ as the coefficient in front of energy $E$ in the exponent $\exp(-\beta E)$. Exponents have to be dimensionless so $\beta$ has to have units of inverse energy. That's why it has to be objects such as $\beta=1/kT$ because $kT$ has units of energy. The latter statement holds because the energy per degree of freedom increases with the temperature. At the end, that's the fundamental answer to your question. The exponential is $\exp(-E/kT)$ because $E\sim kT$ and "hot" means "highly energetic". It's linked to the fact that the temperature has an absolute lower bound, the absolute zero, much like energy is bounded from below.
Answer: Sometimes a definition is just a definition.  The underlying math of statistical mechanics demands that we work with $E/kT$ quite a bit, and historically, we've chosen to work with $\beta \equiv 1/kT$.  This can make some mathematical manipulations easier:  for instance, $\frac{\partial}{\partial \beta} e^{\beta E} = E e^{\beta E}$ is easier to work with than if we explicitly left in a division (but there is "conservation of misery" here, as my advisor likes to say, where the nice things we get for doing this cost in converting from $\partial/\partial \beta$ to $\partial/\partial T$ down the road).
You're entirely free to rewrite the whole of statistical mechanics in terms of some different parameter that is proportional to $T$.  Call it $\tau$ if you like.  $\tau = kT$.  This can be an illustrative exercise for the inquisitive mind, seeing how it makes some expressions simpler and others more laborious.
Answer: In statistical thermodynamics, when using the method of Lagrange multipliers, we obtain an expression as
$$-\ln \rho = \alpha + \beta H$$
where $\alpha$ and $\beta$ are the multipliers to be determined. Multiplying by the Boltzmann constant and averaging we obtain the entropy
$$\langle S \rangle = k_\mathrm{B}\alpha + k_\mathrm{B} \beta \langle H \rangle$$
Comparing with the thermodynamic entropy for a closed system at constant composition (Euler expression)
$$S = S_0 + \frac{U}{T}$$
you obtain the value $\beta = 1/k_\mathrm{B}T$.
You could try an alternative method by defining a Lagrange multiplier $\beta' = 1/\beta$,
$$-\ln \rho = \alpha + H / \beta'$$
Repeating the above procedure you would obtain the value $\beta' = k_\mathrm{B}T$, but I do not find any advantage in this.
Answer: $\beta$ is the fundamental quantity that appears in the laws of statistical mechanics, and comparison with the laws of thermodynamics then implies that
$\beta$ is inversely proportional to the temperature. This can be seen from the
first law, which says $dU=TdS-PdV$, while statistical mechanics provides at constant volume the formula $dS/k_B=\beta dU$. As a consequence, $\beta=1/k_BT$.
Therefore a ''temperature'' defined to be proportional to $\beta$ would measure coldness rather than hotness.
It is a historical accident that temperature was designed to measure hotness rather than coldness. The correspondence between statistical mechnaics and thermodynamics would be simpler if it were otherwise, but one cannot change history and the resulting tradition deeply rooted in our culture.
Comment: All so very true.  One advantage of using $\beta$ as hinted at by Neumaier is that the absolute zero  conundrum goes away.  One can make $\beta$ as small as one wishes without having any problems.  But you'd have to make $\beta$ infinite to get to "absolute zero".


How do I set the privacy for a single pic/photo in Facebook?

Question: I want to restrict viewing of one of my single uploaded pic on Facebook. How do I do that?
Answer: Photo permissions are set on an album basis.  You need to put the photo in its own album, or in an album with other photos that you want to have the same permissions, and set the permissions on that album (Account » Privacy Settings » Customize settings » Edit privacy settings for existing photo albums and videos).
Answer: I stumbled upon your question while searching for a similar kind of activity on my timeline picture in facebook. You can go to the picture and hit the edit button and choose custom.
There you will get 2 options - "share this with" and "Don't share this with". Go to the latter and manually enter the names of people whom you wish to exclude. Then, hit "save changes" > "Done editing".
There is another way, you can group them in a single list of people for minimal notifications sharing, so that you can restrict them from viewing your posts in future without manually entering names each time. Hope this helps all, who are wandering for a solution like I did.


Post workout - workout, is it really helping?

Question: I have a 3-4 day a week weight workout plan, each day focuses on squats, bench press or deadlifts as the primary and some auxiliary exercises (overhead press, crunches, etc.).  I've recently added very light exercises at the end of the main workout to help stretch out muscles, etc. with the hope of doing an active cool down and prep'ing for the next workout.  For example, if today is bench press day and tomorrow deadlift, I might do some very light deadlifts or good mornings.  I think this is helping in that the next workout I'm able to lift a bit heavier.  The question: Is this post workout, light workout actually helping because it's stretching the next target muscle group OR is it mostly a psychological thing where my mind is focusing on the next workout sooner?
Answer: I would say a little bit of both. When you do those "Warm-ups", you're still working out those muscles. You go home and sleep, where you recover (build strength). Then, you go back to the gym go heavier. I say both because it's one of those things, if you believe it works it will.


How do I know if food left at room temperature is still safe to eat?

Question: If I left food out of the refrigerator for some period of time, is it still safe? If I left it out too long, can I salvage it by cooking it more?
Comment: Pro tips: bookmark this so you can find it when you want to close duplicates, and since the answer here is very general, consider adding a comment with specific advice when you vote to close!
Answer: When in Doubt, Throw it Out!
You cannot always see or smell bacterial contamination. Mold that appears to be growing only on the surface may grow invisible roots into softer foods. Do not rely on a visual inspection or "smell test" to tell you whether or not a food is safe. It's not worth the risk - food poisoning can be much, much worse than an upset stomach.
The Danger Zone

Per the USDA guidelines, potentially hazardous food that stays in the temperature "danger zone", 40-140 °F (4-60 °C), for more than 2 hours should be discarded. For temperatures above 90°F (32°C), the limit is 1 hour.*

Potentially hazardous foods are those foods that spoil most easily, such as unshelled eggs, raw meats, fish, shell fish, dairy products, almost all cooked foods.

This time is cumulative, so it includes time bringing the food home from the grocery store, time before cooking, time after cooking, and so on.   The reason is that while cooking may destroy bacteria or other pathogens, it doesn't always destroy the toxins that they have produced.

In general, regarding perishable foods like meat, most dairy, unshelled eggs and shell eggs (in the US), cooked casseroles, and so on:  if the food (or its perishable components) have been at room temperature for more than two hours, you should discard that food.

To avoid the danger zone, keep cooked food hot until ready to eat, then refrigerate immediately. Separate large items into smaller containers to help them to cool more quickly. If you're defrosting something, do it in the fridge or under cold running water.

If you can be certain that the food was not in the danger zone, then yes, it is safe. For example, if you left a large chunk of frozen meat out and it is still frozen solid (including the surface) when you come back to it, it was not in the danger zone.

Why is it so strict? / Why didn't I get sick?
These guidelines are about making sure you don't get a foodborne illness, i.e. reducing the risk to where it's so small as to not be an issue. So if you break the rules, e.g. eating food that's been left at room temperature for 8 hours, that doesn't mean you will get sick, just that you're taking a risk.
Why does cooking not completely "reset the clock"?

Some bacteria leave behind harmful protein toxins that cannot be "killed" (denatured) by cooking. Cooking food is only effective against live organisms, not their toxic waste products. Spoiled food cannot be cooked back to safety and must be discarded.

Cooking is pasteurization, not sterilization. Pasteurization means killing most microbes, so as to render the food safe for human consumption.  Sterilization methods (e.g. pressure-canning and irradiation) are the only safe methods for longer-term room-temperature storage. Otherwise, the danger zone rules always apply.

Even sterilized food can only remain sterile under an airtight seal, e.g. when properly canned or vacuum-sealed. Once it is opened, it is no longer sterile. Air contains countless bacteria and molds, and their spores, which will readily re-colonize any suitable environment they encounter. Cooked food tends to be an ideal medium for growth.

What can I leave out longer?
For foods that aren't potentially hazardous as described above, there's no solid rule, but things are generally safe for much longer than the 2 hours given above. For example, things which are sold at room temperature (e.g. fresh produce, bread, or cookies) are most likely safe at least all day or overnight if not for days or even months. You can find guidelines for common things at StillTasty.
Regulation and Risks
Follow the guidelines set out by reputable regulatory agencies, especially when serving others. Local organizations include:

FDA Food Code (USDA)
CFIA (Canada)
Food Standards Agency (UK)

Other regulatory sources apply in other parts of the word, but major food safety organizations usually agree in essence (if not in complete detail) on most issues.
Failure to follow reputable guidelines is irresponsible if you are serving guests, and failure to follow your specific local codes is likely to be illegal if you are serving customers.
Health codes tend to be very conservative, to fully protect the community.    You have the right to take risks on yourself by ignoring their recommendations, but please do not risk the safety of others.
Again, When in Doubt...
Once again, if you suspect spoilage or contamination, please, throw it out.
* Note: this is the USDA's rule. Other agencies may have variations on it. Additionally, government agencies generally make very conservative recommendations - they're trying to make sure that no one who follows the rules gets sick. Breaking the rules means maybe taking on some risk. That's up to you - just remember, eventually someone gets unlucky, and food poisoning is not fun.
Helpful Resources

Wikipedia: Food Safety
USDA Fact Sheet
Still Tasty - has information on storage methods/times for almost every food.

Further Reading/Frequently Asked

Why is it dangerous to eat meat which has been left out and then cooked?
How long can I store a food in the pantry, refrigerator, or freezer?
What Do I Need To Know About Temperature and Food Safety?
Is there a problem with defrosting meat on the counter?
How long can cooked food be safely stored at room/warm temperature?
Is it safe to cook a steak that was left out (raw) for 7 hours?
How long can eggs be unrefrigerated before becoming unsafe to eat?
Should I refrigerate eggs?
Comment: I strongly disagree on dairy. In many European countries cheeses are sold at room temperature and are absolutely fine to eat, and you can definitely keep it out of the fridge for more than two hours with no issue whatsoever. Preserved meat (salami, ham and in general *Charcuterie*) can be kept in a cool place outside of the fridge for months with no problem. In summary, you cannot generalize.
Comment: Rules like this are devoted to big distribution, food industry, public restaurants etc. That a bowl soup is dangerous after a couple of hours in my kitchen is ridiculous. They are kinda laws and have regulatory purpose. It is not a kitchen book. Still the answer is good as for it provides guidelines. But it should be taken with one, even two, grains of salt.
Comment: Perhaps this answer should be clarified to point out that the "danger zone" applies to the _food's_ temperature and not to the _ambient_ temp around the food.  For instance, if you set some frozen meat out to defrost at room temperature, it hasn't gone bad after sitting for two hours.  It's probably still frozen solid at that point.  The "danger zone" timer is only ticking when the food's internal temperature is between 40 and 140°F.  Similarly, putting warm food in a fridge/freezer doesn't immediately stop the clock, as it takes some time for the food's internal temperature to drop.
Comment: @Steve absolutely! My fridge went on the blink last month, but it didn't stop working it just sneakily got warmer. Our first clue was milk kept spoiling. I now own two fridge thermometers, for fridge and freezer. ~$5 each, well worth it.
Comment: It's also a good idea to keep a thermometer in your fridge. They typically don't have built-in temperature readings, and you may be inadvertently endangering yourself and your guests.  The appropriate temperatures are discussed here: http://cooking.stackexchange.com/questions/12013/what-is-the-ideal-fridge-temperature
Comment: @nico I agree that this answer is totally irrelevant concerning questions about *food preservation methods*.  "How do I correctly and safely determine how long food preserved with X method will last" is not in any way answered by "put it in the refrigerator".
Answer: The question was: "If I left food out of the refrigerator for some period of time, is it still safe? If I left it out too long, can I salvage it by cooking it more?"
Answer: It depends ...

How long did you leave it outside the fridge?
What kind of food are we talking about?
What is the moisture content of the food and the humidity of the air in the room?
Is the air reasonably clean. Did you put it on a clean or contaminated surface?
Is it raw or cooked food?

These are just a couple of questions so you get the general idea that it really is impossible to give a generalized answer to the question.
Considering that only a surprisingly small percentage of the worlds population actually has access to refrigerators and people still eat I think it might be obvious that refrigeration is really not the only way to store food for later consumption.
For a more in depth study of the topic I recommend:
Food Safety: The Science of Keeping Food Safe By Ian C. Shaw
As a more general tip I would stick to common sense. e.g. any food containing raw eggs (Mayonnaise) or food that must by its nature be considered contaminated (store bought raw chicken / raw meat) needs to be handled in a reasonable matter (you should be able to find the correct advise about handling these kinds of foods in any good cookbook) to avoid colonisation to an unhealthy (when eaten - even after cooking) point. On the other end of the spectrum leafy vegetables or fruit bought fresh from a farmers market actually comes with its own protection in the form of beneficial bacteria on the skin and is therefore less likely to be easily (meaning in a short time) colonized by pathogenetic organisms. Learn about your food and learn how to cook and you probably will be safe.
Comment: Anecdotally, I routinely leave (vegetarian) dishes out, not just for two hours but overnight, and have observed that they're always fine. Unless they've been exposed to human saliva, in which case they're furry in the morning, or it's the middle of summer and the house isn't cooled, my observations lead me to believe that a lot of dishes are fine sitting out to cool. (I developed this habit when I had a fussy and ancient fridge, which would labor whenever hot foods were placed in it.) I would never leave, say, fresh homemade mayonnaise out, but a pot of curried chickpeas? No problem.
Answer:
If I left food out of the refrigerator for some period of time, is it
  still safe?

It all depends on measures you have taken to prevent spoiling. There a fair few types of charcuterie that is aged for anywhere from a week to several months. So in a general sense yes CERTAIN foods can be safe to eat even when not refrigerated. The thing is these foods have been prepared in a manner that prevents harmful bacteria from growing.
Salami for instance uses salt to cure the sausage and then also adds further acidity to the environment by the addition of wine. This ensure that harmful bacteria is unlikely to grow.
Biltong and to a lesser extent Jerky as well is pieces of meat that is cured in salt and then to remove the salt a vinegar bath is used to also add further acidity and reduce water content of the meat.
These examples seem to be the exception though as it seems you want to know if food that is not specifically prepared for long term curing is safe to leave outside and to that I would say a resounding NO.
Answer: (in reply to a closed question:

I left two bags of groceries in the car overnight. A beef shoulder roast, a pork loin, pack of ground beef and some smoked sausage. They were cold to the touch. That was our food for the week. Not sure what I should do.

The rule of thumb (and of the USDA) is: after two hours in the "danger zone" - temperatures between 5-60c/40-140f - the food has to go. That's the official answer and the only responsible one.
But it's indeed a one-size-fits-all-play-it-safe rule. Bacteria's growth rate rises with temperature until they start dying around 60c/140f. Two hours in a humid 40c/105f will turn fresh meat into a small civilization. But under 10c/50f there'll hardly be a change.
So as Kate Gregory wrote, the question is where you are, and how cold is it over there. If your food was left covered in cold "storage" temperatures, and in the morning felt cold and firm to the touch and smelled fine, it has stayed unspoiled. Problem is: you can't know. I still might be unsafe. Not all food spoilage shows or smells.
Still, if you consider taking the risk, you should always throw away the ground beef. Bacteria grows on the surface of foods. According to common sense, you can make a wholesome piece of meat safe by cooking it and sterilize its surface (only that here you need to be guided not by common sense but by a health expert). But either way - in ground meat the outside and the inside are mixed, and any contamination on the meat was spread all across it before the fearful night. So give up the ground meat and


Can I put a secondary fermenter in room temperature without creating any off flavors?

Question: I would like to have more brewing capacity, but I am limited by the amount of temperature controlled storage that I have.  Do you only need temp control in the primary fermentation process?  I'm thinking that I store the bottle beer at room temperature, so what is the difference in storing the beer in the secondary at room temperature.  Please let me know.
Answer: I have found that temperature fluctuations produce off flavors much more than the actual temperature level. As long as it's "close" to the temperature recommended for your yeast you should be fine.
Answer: It's more important during primary since there the yeast is much more active - there's more opportunity to create esters that you don't want.
Answer: While using the correct temperature for the yeast is important, you can still have a good finished product if it isn't controlled.  The only time I do anything is cool it down if it gets too hot.  My apartment is pretty much always around 70 degrees F and my primary, secondary, and bottle storage is all at room temp.
I might have some slight off flavors from it, but nothing really noticeable.


"A life for a life": execution or reparations

Question: The Torah states (Ex. 21:23) that if two people are fighting and accidentally kill an innocent bystander (such as a woman), "you shall give a life for a life."
The Gemara (Sanhedrin 79a-b) records a debate about the meaning of this verse. The Tanna Kamma states that it means that the killer is put to death, since he did intend to kill someone (the person with whom he was fighting). On the other hand, R. Shimon (and Rebbi) say that he need only pay reparations to the victim's heirs, as evidenced by the term ונתתה ("you shall give"), which as in the preceding verse means a financial settlement.*
Now, the same expression is repeated in Lev. 24:18, where it refers to one who kills an animal. There, obviously, it means that he pays for its value (as indeed the Torah itself makes clear three verses later: "one who kills an animal shall pay for it"). That being the case, on what grounds does the Tanna Kamma say that in the first-quoted verse (about killing the bystander) it means execution rather than reparations?

* Actually, Rambam (Hil. Rotze'ach 4:1) understands R. Shimon's opinion to be in accordance with the view of Tanna D'vei Chizkiyah (in that same sugya), that the assailant is liable to neither death nor payment. Tosafos there (ד"ה ומפקא) points out that Tanna D'vei Chizkiyah must therefore necessarily understand the case in Exodus to be talking about where the assailant did intend to kill the woman, and then he is indeed subject to the death penalty; they would exempt him only if indeed he didn't intend to hit her. (Which means that the same question would apply according to this view as well.)
Comment: Seems to me that its based on a feeling of injustice, but just speculating.
Comment: What about if you're fighting in self defense?
Answer: It seems that y'shal'mena necessitates a monetary interpretation, whereas v'nasata is vague enough that the Tanna Kamma followed the more apparent meaning.


Microsoft Word Complains me this phrase is wrong - Is it right?

Question:
A programming craftsman having hands on knowledge in Web development
  (Including user interaction), Software Development Life cycle, and
  database programming

How should the sentence be formed so that it is correct( I am not sure this is wrong).
Answer: There are various issues here which may raise flags such as:

No finite verb
No full stop
An idiosyncratic use of capital letters such as "Including" in the middle of the phrase
Comment: 4. A missing hyphen.
Answer: Strictly speaking, this is not a sentence, as it contains no finite verb. You have written an explanation of someone's qualifications on a specific branch of knowledge, similar to the much shorter (Name,) Teacher with MA in Linguistics. Word doesn't recognise these strings as sentences, although they aren't wrong. If you want to convert it into a sentence, it would be something like:
He is/I am a programming craftsman with hands on knowledge...
Answer: This is not a sentence but a phrase, specifically a Noun Phrase.
I suspect that the error message you are being given in Word would be 'fragment'; am I right?
In order for this to be a complete sentence, you require a verb. Upon adding the verb, this phrase could then be made either the subject or object of your sentence. I assume you want the following:
I am a programming...
That said, there is nothing wrong with using phrases as long as they make sense in context. If you are listing attributes, say for a CV, then bullet-pointed phrases like this are normal.


Gradient of a Scalar Field is Perpendicular to Equipotential Surface

Question: let $\phi = f(x,y,z)$ be a scalar field, is gradient of phi independent of coordinate choice?
Also how to prove that $\nabla \phi$ is perpendicular to scalar potential surface.
Comment: This question and this answer can give you too a direction:http://math.stackexchange.com/questions/401845/why-the-nabla-fx-in-the-direction-orthogonal-to-fx/402080#402080
Answer: A simple way to understand this in an arbitrary dimension, is the following (you can make it rigorous if you work a little, but I doubt that there's a way to avoid the implicit function theorem).
The directional derivative of $\phi$ at the point $\vec r$ and in a direction $\vec u$ is given by $\vec u\cdot \vec \nabla\phi$. It is the derivative of $\phi(\gamma(t))|_{t=0}$ if $\gamma(t)$ is a curve such that $\gamma(0)=\vec r$ and $\dot \gamma(0)=\left.\frac{d\gamma}{dt}\right|_{t=0}=\vec u$. If $\gamma$ is contained in the equipotential surface, then clearly $\dot \phi=0$ identically, and in particular the gradient is perpendicular to all $\vec u$'s which are tangent to the equipotential surface.
To answer your question about coordinate independence, the gradient is a vector. As such, it is a geometrical entity that does not depend on the choice of coordinates. However, its coordinate representation clearly does depend on the choice of coordinates, but in a simple manner: a rotation of the coordinates will result in a rotation of the vector of components.
Comment: @Bruno 23 secs ahead of me! ahhh!
Comment: Bah, so here's mine! take that!
Comment: Great minds think alike! Have my upvote. :)
Answer: Here is an intuitive explanation. Let $p$ be any point. We want to show that $\nabla \phi(p)$ is perpendicular to the surface $\phi(x)=\phi(p)$ which passes through $p$. Let $\vec v$ be any unit vector at $p$. By the chain rule, the directional derivative of $\phi$ in the direction $\vec v$ at $p$ is
$$\vec v \cdot \nabla \phi(p).$$
If $\vec v$ is tangent to the surface $\phi(x)=\phi(p)$, the directional derivative is $0$ because $\varphi$ is constant on the surface $\phi(x)=\phi(p)$. Hence this means $\vec v$ is perpendicular to $\nabla \phi(p)$.
Answer: First, when you say that the gradient is perpendicular to the scalar potential, you need to be clear that you really mean it is perpendicular to the normal vector of the surface described by that scalar potential (i.e. $\phi(x,y,z)=0$). A vector can't be perpendicular to a scalar, except w.r.t. that scalar field's normal vector.
At some particular point (x,y,z), use the implicit function theorem to solve for a surface as a function of (x,y), that is $z(x,y)$. Then the normal vector of this surface is defined as the cross product of the two partial derivatives, $\vec{n} = \frac{\partial}{\partial{x}}([x,y,z(x,y)])\times \frac{\partial}{\partial{y}}([x,y,z(x,y)])$.
Since these two vectors form a basis for the tangent plane, and the gradient lies within the tangent plane, then the gradient vector must be perpendicular to the surface normal (because the normal is the cross product of vectors in the tangent plane, and is hence perpendicular to vectors in the tangent plane).
A definition of the gradient that does not make reference to any particular coordinates is given by
$$\nabla \phi = \lim_{S\to0}\frac{1}{V}\oint_{S}\vec{n}\phi{dS}$$ where $S$ is 'surface' bounding a 'volume' $V$ with the convention that, when implied by the dimensions of the problem, $S$ will be taken to mean a patch of a 2-D surface or an arc of a curve and $V$ will analogously be the area or length, respectively. Using this, you can show that the different ways of calculating the gradient in different coordinate systems are equal.
As a side note, your intuition should tell you that the gradient, and other vector quantities that arise in physical identities, ought to be independent of the coordinates because otherwise, certain physical laws would change just by changing the coordinates you work with, which doesn't make physical sense.
Comment: *perpendicular ;)
Comment: I would be very interested in seeing a proof that the usual coordinate-independent definition of the gradient at a point $p$ (namely that the gradient vector $\nabla \phi(p)$ is the unique vector such that $df_p(x) = \langle \nabla \phi(p), x \rangle$ for all $x$) is equivalent to yours. Can you suggest a reference?
Comment: [These MIT notes](http://stuff.mit.edu/afs/athena/course/8/8.02-esg/8.022/notes/vecops.pdf) mention the integral definition, but the directional derivative one that you mention is just as good.

@Bruno -- fixed the typo, thanks!


Does Tiny Death Star earn more credits with the game open, or closed?

Question: Do you earn more credits if you're actively playing tiny death star (elevator, etc) or while the game is closed and off?
Answer: I performed the following experiment, in each case counting the credits earned and number of levels that were open and selling items.  Note that my elevator is the 10PPM model:

Play TDS for 10 minutes, using the elevator and keeping only the top item (3 credit item) in stock for each level.
Turn TDS off and wait ten minutes.

Results:

4,420 credits using 31 active levels (PPM: 4.75)
8,187 credits using 27 active levels (PPM: 10.11)

These two tests were performed consecutively.  It appears that TDS uses a different model to earn credits while you are actively playing the game vs when it restarts and calculates all the expected earnings.
The difference is staggering, and if your goal is credits you should be playing for brief periods of time infrequently, rather than constantly.  You won't be able to make many bux that way, though.
This is from tests conducted after the 1.3 update in early February 2014, and this may change over time, particularly since it appears to be a bug - you should be earning according to your elevator speed in the game as well as out of game. Tested on iOS - I expect it will be the same on other platforms, but it's possible that the timing code is platform specific, so it might be different.  Would be worth more testing.
Answer: I'm on Android, my data (with the phone closed between writing down the numbers):
At 3:41 my store's stocks were
193, 245, 305
At 4:20,
62, 114, 174
At 4:29
31, 84, 144
That's a steady 10 customers per minute.  I have the level 4 elevator, which says it has a rating of 14 ppm.
(I need to redo data while open)
Comment: Can you perform the same test with the game running so we can compare the two?


How do I test an image of ubuntu using the test tracker?

Question: I've downloaded a ubuntu image and I would like to run some tests against that image. How can I test the image on my machine? What tests are available to run and how can I report my results and bugs?
Answer: Assuming you downloaded a non-release image (that is to say, an image intended for testing), the ISO Tracker contains a list of tests meant to be executed for the image. For example, a daily ubuntu amd64 image has, as of this writing, 21 testcases representing different scenarios for installing and using the ubuntu image on your machine.
These tests can be seen, executed and reported all using the ISO Tracker interface. A tutorial on using the tracker can be found here. You will need a launchpad account to login and report results. Each image contains download links for the image, instructions for reporting bugs, and a form to submit results. In general you can utilize your machine, or a virtual machine for testing. Real hardware testing is encouraged, but don't overwrite your current installation and data unless you understand what your doing! Virtual machines such as Virtualbox, Vmware player, or KVM are common for virtualized testing.
If you are using a release image of ubuntu and encounter a bug, you are encouraged instead to file the problem as a bug.
Answer: If you reboot onto the disk and press any key before bootup, to bring up the disk menu, then you should be able to run the self test.
Answer: In addition to Neojames answer, you can use virtualbox to install it and run your tests on it without having the need for reboot