How do I make my pannier bag less smelly?

Question: Because I ride my bike everywhere, my pannier bags (Ortlieb Back Roller Classic) carry all kinds of cargo, from wrapped-up fish-and-chips to damp swimming and gym kit. I store them open whenever I can, so they're not as ripe as you might think, but they've still developed a distinct odour over time. What's the best way to wipe down the inside and leave them smelling like new again? Do you have any recommendations for a particular cleaner that won't damage the waterproofing, or a special technique that gets rid of the bad smells?
Comment: What are they made of? Cloth bags are washed differently than PVC-lined bags.
Comment: They're plastic ones. Tough nylon weave for the flexible parts, with a waterproof coating.
Comment: Soap and water, and a hose. That's how I clean my Ortlieb rollers.
Answer: I know it sounds too simple, but these bags are made to be cleaned (assuming yours is unlined. If it's lined, you'll never get it out).
First, try dish soap and water. Citrus scents seem to cut the smell best, but that may be a personal preference.
If that is not enough, then the next best option is to use a diluted solution of something like Pine Sol or other bath, kitchen and tile cleaner.
I've used Pine Sol in a 1:4 ratio with water, and it did the job that dish soap wouldn't.
Another thing to consider:
Seal the products you are carrying better.
Don't take fish just wrapped in newspaper like the fish market gives them to you. Ask for, and insist on if necessary, a ziplock or similar plastic bag or wrap to keep the fish oil off of your bag.
For Gym clothes, pack them in vacuum storage bags like you get for packing luggage tightly. Push the air out of the bag, and it will keep the nasty sealed in well enough to keep your bag form smelling.
They come large enough to put most anything that will fit in your panniers or messenger bag, (even newspaper wrapped fish), and they don't take up much room when empty.
Comment: I am a proud owner of an Ortlieb Downtown, and I confirm - yes, it's that simple. I've had a major lunchbox failure inside this bag and I've had no problem cleaning it. Use water with dish soap, rinse, air dry. That's it.
Answer: If the material seems unwashable try filling a thin sock or pantyhose with baking soda/sodium bicarbonate and dust the inside with it.Open the flap and tap the sock against the interior just hard enough to leave some of the powder over the entire interior.Let it sit overnight and vacum out any residue.You can leave the sock in the pannier so it will continue to absorb odors or try some charcoal in a small cloth pouch.Charcoal can be the kind used for grilling but make sure it is lump charcoal without any self ignitor added.
Comment: The same can be said for climbing chalk, as I discovered riding home from a climb one day. I presume the chalk absorbed some of the odors, and that the chalk spillage (don't ask) dried out the moisture, stopping or at least impeding some mould/organic reactions.
Answer: I like the baking soda comment. Depending on your humidity, you might be developing a mildew smell, which can also develop in cycling jackets if you ride in the rain frequently, too. If you have a warm sunny day, and can turn the bags inside out, sunning them can also be effective. If your bag gets damp (inside) frequently, dry it out promptly and wad up newspaper in it, and that should absorb moisture from a bag (works for gloves and shoes.)
Soaking in a saline and vinegar solution can cut mildew solution. You can add garden herbs like sage or rosemary leaves. If this is not effective, I would move up to some Simple Green solution next.
If those solutions are ineffective, you could also trest a small section of the bag with a TSP (trisodium phosphate). TSP is harsh so use gloves, safety glasses. This is probably safer than washing with a bleach solution, but doing a test on a section to determine if how it treats your material.
Comment: If you're limited to commonly-available "household chemicals", I'd suggest first soaking in an ammonia water solution (1/2 cup to a gallon or two), draining well, then soaking in a gallon or two of water with about 16 oz of hydrogen peroxide (2% or 3% from a pharmacy).  This is a good formula to decompose fatty acids and other organic compounds.
Comment: Good answer. I don't think it is mildew in this case, as it's not that kind of smell. The bags are waterproof, so they never get wet inside. I'll bear it in mind just in case.
Answer: I have cloth panniers with a piece of stiff plastic riveted to the inside back wall so turning them inside out isn't an option for cleaning.
Using a mild washing machine soap in the bath tub with warm water, I dunked each pannier in and scrubbed all surfaces with a brush. Hung outside to dry and then brought them inside for the remaining dry time using a floor fan to air dry them. Once dry, the final step was to battle the remaining odor of the bags. Taking an idea from an earlier answer, I dumped a sufficient quantity of Gold Bond Body Powder into a sock and proceeded to gently tap it inside each pannier until there was a fine film of powder lining the interior. Just enough to absorb any undesirable odor and make we want to use them again.
Hope that helps.
Answer: Have you tried air and sunshine first? I turn my panniers inside out and put them by an open window every month or two
Turning them inside out also makes it easy to remove debris.
Comment: Alas, Ortliebs have one rigid side, so they don't turn inside-out.
Answer: Since the original comment is attached to a deleted post I'll repeat it here:  There are special odor-killing laundry agents that can be quite effective against certain odors.  One I've used is Scent Killer, a laundry additive intended for use by hunters to remove the odor from their clothing (so they don't spook their prey).
Hydrogen peroxide can also be used for this (though it has a slight tendency to bleach colors).
The same agents can be useful for washing out smelly bike shorts.


What's considered an interaction in Quantum Mechanics?

Question: Clearly I'm not an expert of QM but recently I came across the fact that particles do not have intrinsically a specific location until they interact (very ambigous term to me) with something else and so they wave function collapses into a specific location. My question is: what's considered an interaction? Doesn't particles interact with each other trough gravity and electromagnetism all the time? The effect of gravity is an interaction mediated by the deformation of space-time and so may be excluded but to me EM should make the wave function collapse every instant.
Comment: Note that gravity is a famously problematic force to account for in quantum physics [see here](https://en.wikipedia.org/wiki/Quantum_gravity).
Comment: By definition, interaction is any event which forces particle wave function to collapse. Usually it's absorption or scattering effects under the hood. Also in such events usually particle momentum changes rapidly in short time duration.
Comment: You seem to be talking about a what is normally termed a *measurement*. The term interaction is normally used for interactions between different parts of the system (or the system and its environment) which do not (necessarily) collapse the wave function
Answer: In the quantum mechanical frame, all matter is ultimately composed from elementary particles , at the moment given in the table of particles of the standardm model of particle physics. this is a quantum mechanical model in the framework of special relativity.
This means that Lorentz transformations dictate the kinematics of four vectors, for spacetime $(t,x,y,z)$ and for energy-momentum  $(E,p_x.p_y,p_z)$.
An interaction involves two incoming particle four vectors, on mass shell , i.e. the "length" of the energy momentum four vector is on mass shell, which scatter off each other, ending with two or more particle on mass shell four vectors. Or, another interaction is  one particle four vector which decays into many other on mass shell four vectors.
This is  clear in the pictorial reperentation of Feynman diagrams, which describe the terms of the perturbative expansion the sum of which gives the interaction crossection,( or decay probability.)
Simple example the first order term of the interaction  electron scattering off an electron :

The famous "collapse" just means one instant in the probability distribution , which is the calculated crossection for the interaction. The quantum mechanical predictions predict the probability of interaction for each event, and a large number of events has to be accumulated in order to test a hypothesis.

but to me EM should make the wave function collapse every instant.

The interactions you envisage are off mass shell, like the photon in the diagram above, they are virtual "interactions" so do not fall into the collapse scenario, which in my opinion is a bad analogy anyway. The wavefunction is not a balloon.
Answer: Your question is actually related to what is known as the measurement problem; a yet-unsolved problem in quantum mechanics and the different interpretation of quantum mechanics give different answers.
According to the standard interpretation (Copenhagen interpretation), the wavefunction collapses when interacting with a measurement device not when interacting with other particles. Then the question would be: what does count as a measurement device?
The Copenhagen interpretation does not give a clear definitive answer and simply appeals to the intuitive classical notion of a macroscopic measurement device, thus drawing a vague boundary between the quantum and the classical worlds.
This is an unsatisfactory answer because, in the end, any measurement device is actually composed of other elementary particles!
This problem motivated physicists to propose other interpretations of quantum mechanics. Here are a few examples, just to give you an idea of how wildly-different these interpretations are:

Spontaneous collapse theory: The wavefunctions of fundamental particles have a fixed probability per time of collapsing. The probability for a single particle is extremely small but a large collection of entangled particles (like in macroscopic objects) would a very high probability.
Many-World Interpretation: The Wavefunction never collapses but the world keeps splitting into all the different possible states allowed by the wavefunction.
Hidden-variable models like Bohmian mechanics: The particles have definite positions all the time and the wavefunction just represents our ignorance about that.
Answer: to add to what Quantum-Collapse said:
interaction between particles (or quantum systems) is manifested in the Hamiltonian operator, and taken into account through the wave function.
for example, coloumb interaction between 2 electrons is represented in the Hamiltonian equation as a potential term, in addition to the kinetic terms of both particles:
$$H=\frac{|\textbf{p}_1|^2}{2m_e} +\frac{|\textbf{p}_2|^2}{2m_e}+\frac{Ke^2}{|\textbf{r}_1-\textbf{r}_2|}$$
with the standard definitions of momentum:
$$\hat{p}_j=-i\hbar\nabla_{(j)}$$
in such case you have to solve the Schrodinger equation for a wave function of the 2 positions (or momenta) $\psi(\textbf{r}_1,\textbf{r}_2)$


Why is Jiagedaqi part of Heilongjiang despite being inside Inner Mongolia?

Question: Why is the Jiagedaqi (or Jagdaqi) District under the jurisdiction of Heilongjiang Province even though it lies entirely within Inner Mongolia? What is the history of this arrangement?
Comment: The [Wikipedia page](https://en.wikipedia.org/wiki/Jiagedaqi_District) is gives little detail but does mention that the government of Inner Mongolia disputes this arrangement.
Answer: As J. P. Morgan once said, there are two reasons, the official reason and the real reason.
The official reason is that has no proper site for a provincial seat, in Daxinganliang where Jiagedaqi is located, and it therefore needs to be administered from Heilongjiang.
The real reason is that it is more mountainous and forested than the rest of Inner Mongolia, and its mineral resources fit better with Heilongjiang's industrial economy than with Inner Mongolia's agricultural and pastoral economy. Heilongjiang will fight very hard for these resources, and has more to gain that Inner Mongolia has to lose. Also, Heilongjiang has more clout because Inner Mongolia is an autonomous region. Heilongjiang can argue that it is better for Jiagedaqi to be part of the Chinese "mainstream."
It is worth noting that prior to the Communist takeover, parts of present day Heilongjiang were then part of inner Mongolia. So these things are subject to periodic border adjustments, etc, with the latest one going "against" Inner Mongolia. It's almost like a border dispute. Why did both Germany and France fight over Alsace-Lorraine? They both wanted the region's iron ore. Unlike say, Germany and Alsace Lorraine, or Germany and the Sudetenland, this is an internal Chinese matter; "foreign affairs" is not part of the picture. Both Heilongjiang and Inner Mongolia have been part of China since the Qing dynasty (1644), except for a brief interruption by Japan's Manchukuo between the world wars.
Answer: I think this is because Jiagedaqi is rich in minerals such as coal, graphite, gold and zeolite. Now, we all know that the Chinese are after minerals to boost their industry, and losing it to an autonomous area requires bureaucracy for getting those minerals out.
Maybe?

Ecological Resources. Qitaihe is located in the semi-mountain area of Wanda
  Mountain with rivers, forests, and abundant rainfall and mineral resources, which include
  coal, gold, graphite, marble, limestone and zeolite.

-PRC: Heilongjiang Energy Efficient District
Heating Project
Comment: Given that this question has a generous bounty on it, I think the OP is hoping for a bit more research and not just 'maybe?' as an answer.
Comment: I am. It's also a nice start, so thank you to nandan anyway. (Is "nandan"  南丹, or "Southern Dan" or something?)
Comment: Sorry. I am new here. I will try to find out more.
Comment: No. I am actually from India. The name is not Chinese! :)
Comment: Ah right. I don't speak any Indian languages. Do you know the etymology? (If you wouldn't mind sharing :))
Comment: Nandan actually is one of the many names of Lord Krishna (one of the many in the Hindu pantheon of gods). However, like many Chinese, I am an atheist.


Tesla model 3 6-20 charging from existing circuit

Question: I have a 20amp double pole 240v breaker suppling power to my 120v dishwasher and garbage disposal. They share the same circuit. It's 12-3 awg and I have a access to this circuit before it runs to my appliances. I'm interested in know if I can add a junction box to tap into it to supply 240v 20amp to a nema 6-20 outlet. I would only charge my EV when in not running either appliance. It would be nice to throw a switch cutting off power to the appliances while in charging my EV. Thoughts or concerns I'm interested in hearing about it.
Comment: I take it that the circuit has a grounding wire on it?
Comment: What drives this choice? Are you out of breaker space or load calculation? All it takes is one slip-up to pop the breaker, and that's a headache.
Answer: EV specialist.  I applaud your thinking on charging at a sensible intermediate speed other than 50/60A.  This sounds legit to me if you use a switch... however you will need a 2-pole GFCI breaker if you want a socket.
There's no quarrel with mixing 120V and 240V loads and outlets on a MWBC (shared neutral) as long as the breaker is honest 2-pole (2 independents, handle-tied, will not suffice). The problem here is 210.23(B)(2):

210.23 Permissible Loads, Multiple-Outlet Branch Circuits
(B) 15- and 20-Ampere Branch Circuits
(2) Utilization Equipment Fastened in Place.  The total rating of utilization equipment fastened in place, other than luminaires, shall not exceed 50 percent of the branch circuit ampere rating where lighting units, cord-and-plug connected utilization equipment not fastened in place, or both, are also supplied.
NEC 100.1 Definitions.
Fastened in Place: Mounting means of equipment in which the fastening means are specifically designed to permit removal without the use of a tool.

Note that the code says nothing about the appliance being hard-wired vs. cord-and-plug: the deciding factor is whether it's "fastened". And the Code means "fastened or worse", so if the appliance does need tools to remove it, that also counts (disposal).  If the disposal's nameplate says >10A, you lose.  If the dishwasher is fastened in place, and takes >10A, you lose.   And here, "lose" means you'll be required to use that switch.
The switch will need to be DPDT and 20A rated.  Not a cheap piece of kit.  But cheaper than the GFCI breaker, required since you are adding a socket to a garage.
What about eliminating the socket and running to a Wall Connector commissioned for 16A / 20A circuit?  It would certainly be more of a class act - the "draping the cords through the dust and wet" routine is going to get old fast.  That brings us around to

NEC 625.40. Each outlet installed for the purpose of supplying EVSE greater than 16 amperes or 120 volts shall be supplied by an individual branch circuit.
Exception: Branch circuits shall be permitted to feed multiple EVSEs as permitted by 625.42(A) or (B).

So yes, a hardwired EVSE will make the switch mandatory. Effectively, the switch is acting as an EVEMS per NEC 625.42.   A very dumb EVEMS with a 2-digit price, but hey, if a $800 SimpleSwitch can do it, and that thing is literally a switch, then yes.
But the same rule applies to the socket, unless you can say with a straight face that it's for a kiln, welder, compressor, and sure, maybe an EVSE from time to time. It's up to the inspector whether that will pass a "sniff test".
Answer: Yes, you can do this. Is it a good idea? Maybe not.
What you have is a Multi-Wire Branch Circuit or MWBC. This can be powered by two single breakers or a double-breaker. MWBCs used to be much more common in the past as a way to save on wire costs due to the shared neutral. They are less common today due to (a) requirements for GFCI (e.g., dishwasher and disposal which used to not require GFCI but do with recent code updates) and (b) concerns about when they are implemented incorrectly.
GFCI is an important piece of this. An MWBC used only for 120V can have GFCI after splitting the neutral, either as a deadfront for hardwired devices or with a receptacle for plug-in devices. But if it is used for 240V then you must use a GFCI/breaker if GFCI is required. GFCI has been required for a while for disposal and dishwasher (but not nearly as long as for kitchen countertop receptacles) and is now (subject to adoption of the latest NEC) required for most 240V circuits in garage and outside. That most is critical - more below.
With a proper 240V double-breaker, an MWBC is perfectly safe. When implemented using single breakers there are often problems. The breakers in a MWBC need to have common shutoff. Common shutoff can be done as a double-breaker or with a pair of breakers and a handle tie. In addition, if an MWBC includes any 240V receptacles (as you propose), it must have common trip, which is only provided by a double-breaker (you have that, so you're OK). Many older MWBCs don't even have the breakers (or fuses in my case before my panel replacement) connected to each other in any way, which can lead to an MWBC with both hots on the same leg and the possibility of an overloaded neutral and the inability to actually power any 240V devices. You are fine, but I am mentioning all of this because another person with an MWBC might not have a double-breaker and instead have possible issues.
The next possible issue is overloading. This is an issue at any time with any circuit that has multiple receptacles. For example, a circuit that has receptacles in 3 different bedrooms always runs the risk of being overloaded. However, for most circuits, most of the time in most houses, the risks are minimal because most circuits with large loads are:

Dedicated to a particular specific use, as is likely the case with your disposal/dishwasher circuit.
Dedicated to a particular room, such as kitchen, bathroom or laundry room - this allows easy monitoring of usage (e.g., don't use the toaster and the waffle maker at the same time).
Only have occasional usage. For example, with large power tools in a one-person shop, it is unlikely you will run a table saw and another large tool at the same time. (Dust collector is the exception since it can be used with any other tool, so put that on a different circuit and you're all set.)

EV charging changes things. A lot. It is a continuous load, but unlike dryer, water heater, HVAC, etc. it doesn't have to have a dedicated circuit. It is out-of-sight, out-of-mind - e.g., you plug in the car to charge when you get home and then go eat dinner. After dinner you run the dishwasher (not worried about the disposal - you use it for 10 seconds at a time) without even thinking about the car charging on another receptacle of the same circuit.
But technically you can do this. An MWBC can have 240V (6-15 or 6-20) receptacles as well as 120V (5-15 or 5-20) receptacles. I just don't think it is a good idea to use it that way for a large continuous load like EV charging.
In fact, I don't even like it used that way for disposal and dishwasher. Perfectly fine to use an MWBC, but I much prefer hardwiring the disposal and dishwasher. Of course, if you hardwire those devices then you can't use the MWBC for any plug-in 240V loads, assuming the dishwasher uses at least 1/2 of the circuit capacity.
So technically you are OK: double-breaker - good, only receptacles not hardwired - good.
But I am still very concerned about overloading, and there are other considerations as well.
Many EV chargers, and in particular the Tesla Wall Connector, are actually designed to be hardwired. Connecting many of those (there are likely some exceptions) plug-in violates the manufacturer's instructions. There are "travel chargers" designed to be plugged in, but the idea is exactly that, travel. You really should have a hardwired installation for nightly charging.
There is another advantage of a hardwired installation: GFCI. EV service equipment (chargers) already take care of GFCI. But current code (in many places, soon enough in others) requires GFCI for all 240V receptacles in garage or outside, but not for 240V hardwired devices that include GFCI (i.e., EVSE). So if you end up adding a new, separate, 240V circuit for EV charging then connecting it hardwired instead of plug/receptacle saves on the cost of a double-breaker GFCI.


Hydrogen Spectra using Hydrogen Gas Discharge Tube

Question: I am doing an experiment for my lab work which include determination of value of Rydberg Constant using method of Interpolation. For this we first plot calibration curve for various wavalengths observed in spectromenter for Mercury Source and replace light source to Hydrogen Discharge Tube and then interpolate values of angles for H-lines in spectrometer window from calibration curve. Ideally we should see 4 emission lines for Hydrogen H-alpha, H-beta, H-gamma and H-delta lines. But for our source we can only able to see H-alpha (Red) and H-beta (Blue-ish-Green) lines. The possible reason behind this is that our hydrogen source is very dim (intensity of light is small). The voltage of 2000V is applied across the gas discharge tube. So what is reason behind absence of H-gamma and H-delta lines, why we were not observe these lines? If the problem is due to very small intensities of these lines, does increasing the voltage across tube to 2500V or 3000V will help? Does increasing voltage across tube will damage the tube? Is there any upper limit for voltage to be applied across Hydrogen Gas discharge tube? Can I find this upper voltage value in manual of tube?
Comment: If your tube is of commercial manufacture, get and check the data sheet for safe voltage levels.
Comment: Is checked with college lab, they don't have any manual for the tube. Is there any alternative method to find the safe voltage? I know trial and error will not be a good way.
Answer: The hydrogen discharge tubes typically used in student labs are not designed for long-term use. After a couple of years, the tubes leak and air gets mixed with the hydrogen. This causes them to get dim and the weaker lines are almost impossible to see.
It has nothing to do with the power supply and everything to do with how new the tube it and how many hours of use it has seen.
You need a new tube. I know this from many years of running this experiment.
EDIT Addition: In answer to the question about a higher voltage, running at a higher voltage for a new tube might provide brighter lines, but will also cause impurity gases to show their lines.  Higher voltages will also cause much shorter tube lifetimes (faster leakage due to higher temperatures at the penetrations for the wires).  Running a higher voltage on an old, leaky tube will not provide the improvement you need on the weak lines. I've tried it before.


MikTex installation stops showing a list of options

Question: I had to change my computer with WIn10, where I had TexStudio+MikTex.
On the new computer which still uses Win10 I am reinstalling MikTex and TexStudio, but MikTex installer (basic-miktex-22.7-x64.exe) stops showing a list of options "Usage: setupwiz [OPTIONS]". It seems that I should install it manually! Is that right? If so why the manual doesn't mention that?
Thank you for any help.
Answer: Just run as administrator, and it will be solved!


How to test if my app behaves properly when Android OS kills its process?

Question: How can I test whether my app behaves properly when Android OS kills its process due to low memory?
Answer: Just press the home button, you will be able to use onPause and to save your state use: onSaveInstanceState(Bundle) / onCreate(Bundle) to handle recovery.
More on Activities and it's life-cycle: http://developer.android.com/reference/android/app/Activity.html
Answer: I guess you can't actually do anything if the OS terminates the process (this usually happens when your application is already paused or stopped).
See http://developer.android.com/guide/topics/fundamentals.html#actlife
Answer: I guess you don't need the answer anymore, but I was looking for the same thing:
Test onCreate after the Activity was destroyed by the OS.
Here is the simple solution at least for the Emulator:
Open the "Dev Tools" in the app drawer of your emulator, select "Development Setting*s" and activate the checkbox "*Immediately destroy activities"
After this, open your app and leave it via the Home key. Thats it.


TFS - Workspace deleted with pending edits

Question: I had edits on my local machine which had it's own workspace. The machine then crashed. Luckily I was able to recover the edits from the harddrive and place them on my new machine. The TFS admin deleted my old workspace while there were still pending edits associated with it. How can I remove the edits from that deleted workspace?
Answer: Usually, deleting a workspace will also undo any pending edits.  If that's not the case, someone with administrative permissions could use the TFS Power Tools, go into source explorer, select those items that are still pended, and "undo" the changes.
The TFS Power Tools for TFS 2008 can be found here:  http://www.microsoft.com/downloads/details.aspx?FamilyID=fbd14eea-781f-45a1-8c46-9f6ba2f68bf0&DisplayLang=en
Comment: Didn't know about power tools. Thanks
Answer: For clarification in TFS 2010 after you have installed the power tools, do a context menu on the source control directory you want to start from. Then choose "Find in Source Control" > "Status". Enter your search criteria. From the results list you can select appropriate files and then context menu and "Undo".


Do you have to have command line access to use Subversion with Wordpress?

Question: My group does not have command line access to the machine that is running our WordPress instance. However, we would still like to install/update using Subversion. Is this possible? Also, does Subversion need to be on the same machine?
Comment: The reason I ask is because that is the first line on this page --> http://codex.wordpress.org/Installing/Updating_WordPress_with_Subversion
Comment: I would assume that you do, considering it begins with "If you have command-line access...". Are you just concerned about easily upgrading WordPress in the future?
Comment: I am tempted to close this as offtopic, since the question is pretty much about Subversion. You might get better answer for such on other sites in SE network.
Comment: My question is specifically about WordPress and how you implement it with Subversion.
Answer: You would need to have subversion installed on the same machine and command line access to the machine.
Comment: could you explain why? Thanks!
Comment: In order to follow the WP codex directions for installing/upgrading via SVN, you must have it on the same server. I suppose if you have access to another server where you could checkout WP core via SVN, and then your IT dept would allow an rsync between that SVN checkout and the web server, you may be able to get it to work. But if you can't get shell access, I doubt you would be able to setup an rsync for the files. Can the IT department configure SVN and be responsible for running the upgrade? As in you file a ticket with them, and they run the `svn sw` command when it's time to upgrade?


How do I solve this integral $ \int_0^{\frac{\pi}{2}-}\frac{dx}{1+\tan^{\sqrt{2}}\left(x\right)} $? (looking for hints)

Question: I have no idea how to go about solving this integral:
$$ \int_0^{\frac{\pi}{2}-}\frac{dx}{1+\tan^{\sqrt{2}}\left(x\right)} .$$
The most I've come up with is rewriting it as a series to obtain
$$ \int_0^{\frac{\pi}{2}-}\sum\limits_{n=0}^\infty \left\{-\tan^{\sqrt{2}}\left(x\right)\right\}^n{dx}, $$
but then I realized that this resulted in a hideous set of integrations if I were to try integrating term-by-term and then turning the answer back:
$$ \int_0^{\frac{\pi}{2}-}\left[1-\tan^{\sqrt{2}}\left(x\right)+\tan^2 (x)-\tan^{2\cdot\sqrt{2}}(x)+\cdots\right]\,dx, $$
because then I couldn't solve
$$ \int \tan^\sqrt{2} (x) \, dx. $$
So to cope with the above I thought I might expand even further, but then I realized I must be waaayyyyy off track from where I should be.
Comment: $$\frac1{1+ \tan^{\sqrt2}x}=\frac{\cos^{\sqrt2}x}{\sin^{\sqrt2}x+\cos^{\sqrt2}x}$$ Then http://math.stackexchange.com/questions/439851/evaluate-the-integral-int-frac-pi2-0-frac-sin3x-sin3x-cos3xdx/439856#439856
Comment: Thanks for this, I've spotted that relation already but I hadn't thought of what they did in the link you've provided, which is really interesting. I'll give it a shot and see what happens.
Answer: I suggest you use the substitution $x=\frac{\pi}{2}-u$. Then use the identity $\tan(\frac{\pi}{2}-u)=\cot(u)$. Now look at the two different representations of the integral you have and add them.
Answer: $$\int_{0}^{\frac{\pi}{2}-}\frac{dx}{1+{tan}^{\sqrt{2}}\left(x\right)} = \int_{0}^{\frac{\pi}{2}}\frac{{cos}^{\sqrt{2}}\left(x\right)\:dx}{{cos}^{\sqrt{2}}\left(x\right)+ {sin}^{\sqrt{2}}\left(x\right)},$$
$$ \int_{0}^{\frac{\pi}{2}-}\frac{dx}{1+{tan}^{\sqrt{2}}\left(x\right)}= \int_{0}^{\frac{\pi}{2}}\frac{{sin}^{\sqrt{2}}\left(x\right)\:dx}{{sin}^{\sqrt{2}}\left(x\right)+ {cos}^{\sqrt{2}}\left(x\right)},$$
$$\therefore \int_{0}^{\frac{\pi}{2}}\left\{\frac{{cos}^{\sqrt{2}}\left(x\right)}{{cos}^{\sqrt{2}}\left(x\right)+{sin}^{\sqrt{2}}\left(x\right)}+\frac{{sin}^{\sqrt{2}}\left(x\right)}{{sin}^{\sqrt{2}}\left(x\right)+ {cos}^{\sqrt{2}}\left(x\right)}\right\}dx = \int_{0}^{\frac{\pi}{2}}dx=\frac{\pi}{2},$$
which is indeed twice the expected result because we added the two integrals together, so this must be divided by two to get
$$ \int_0^{\frac{\pi}{2}-}\frac{dx}{1+{tan}^{\sqrt{2}}\left(x\right)} = \boxed{\frac{\pi}{4}.} $$
Can be expanded to solve integrals of the form
$$ \int_{0}^{\frac{\pi}{2}}\frac{{cos}^{n}\left(x\right)\:dx}{{cos}^{n}\left(x\right)+ {sin}^{n}\left(x\right)} .$$


Is there a specific synth name/DAW plugin for a sort of 70s jazz flute chorus?

Question: There's a sound I hear in some modern alternative music that has such emotive nostalgic properties. It sounds like a flute chorus I've heard in 70s Japanese Jazz and elsewhere. This short comedic musical video prominently features the old-timey flute chorus in the first half of the instrumental. I would love to use this in my music, but my searches for a flute sound from around that time keep giving me the Korg M1 Pan Flute which is definitely not what I want. Is anyone aware of a name of a synth effect I can look up, or a plugin/vst that can reproduce this?
Answer: That comedy video seems to sample Tina Turner's "What's Love Got To Do With It", which was recorded on a Yamaha DX7 keyboard. Thus, your best chance is getting a DX7 emulation, e. g. Dexed (free) or the one from Arturia, and trying to find the original preset (factory preset #24).
Comment: This led me down a very interesting rabbit hole. Many thanks for introducing me to Dexed, which I will certainly be using in the future. While the video does sample "What's Love Got To Do With It", the trilling flutes are laid _over_ it, and do not come from Tina's song. My search continues. But your research was amazingly thorough and specific, thanks!


Can a stolen Government cheque be cashed by someone else?

Question: I received a trillium check in the mail, I didn't sign it yet. The cheque was stolen and I want to know if she signs the cheque and deposits it into her ATM can she withdrawal the money right away?
Answer: If a cheque is made out to you, and you don't sign it over to them, then it is illegal for them to cash it.
There is nothing physically to stop them depositing it to their account through and ATM. What will happen is:

The money will appear to be in their account, but they will not be able to take it out until the cheque has cleared.
During the clearance process the bank will confirm that the cheque is genuine. Since it is not made out to her they will check that you have signed it.
If it isn't signed then the cheque will be rejected. If the person who stole it has forged your signature then it will probably be accepted. It may at some point be compared to your real signature, but the check may not be a very thorough one. However if they have reason to doubt that you really did sign it then the check will be more thourough. If they detect that you didn't sign it then the money will not be credited to the thief's account (or will be withdrawn if it was previously credited.)

In any case if you know your cheque was stolen your action should be immediately report it to the government that issued it. They will probably invalidate the old one and cut you a new one. Additionally you can report the thief to the police, and they may face crimninal charges.
Comment: If the check was cashed I'd also inform the bank. Or inform them anyway.
Comment: @gnasher729 Which bank?
Comment: Good question. I assumed that cheques are often stolen by people you are living with, who might not be the smartest ones, and whose bank you might know. Might work sometimes.


what is a transverse isotropic rock?

Question: I know isotropic means equal properties in all directions , but the term "transverse" is not making it easy for me to understand.
Answer: You are correct. Isotropy means that the property at some specified point (X,Y,Z) is the same, whether the measurement is made along any direction.
If the property varies depending on which direction you make the measurement in, then that property is said to be "anisotropic". For example, the permeability of a material (i.e. its ability to conduct fluids) may be anisotropic if fluid can move preferentially in one direction and it would be difficult for it to move in a different direction (like the tubes below). This means, the permeability of this material at a given point (X,Y,Z) depends on which direction you make the measurement, i.e. high permeability parallel to the tubes, low permeability otherwise.

Transverse isotropy (also called hexagonal symmetry) is a special kind of anisotropy in which there exists a special "axis of symmetry" such that the property you are measuring appears to be the same as you make measurements perpendicular to this axis. Basically, rotating around this axis of symmetry, the property looks pretty much the same, i.e. it is isotropic in this transverse direction. However, once you go off axis, then the measured property will change.

In geology (especially in sedimentary geology), transverse isotropy is usually a good approximation to many phenomena (elasticity, permeability, heat conductivity, etc.) due to the fact rocks are deposited mostly horizontally. This means that things will look very similar laterally (in both N-S and E-W directions) but very different vertically.

Finally, transverse isotropy is just an approximation to the much more complex nature of real rocks. If you were to add multiple sets of fractures to a rock on top of its layered nature, you will need to use a "less symmetric" model to describe it: orthorhombic, monoclinic, or triclinic. But for most practical purposes, transverse isotropy does a pretty good job.
Hope this helps!
Answer: As I understand it, "tranverse isotropy" has to do with seismic properties of a rock, a rock unit, or even a specific mineral. It's an important term because even though a rock may appear "isotropic" visually, it may have an internal fabric (invisible to unassisted eyes) that treats seismic waves differently depending the axes through which they are propagated.
Internal fabrics can be the result of crystalline alignment from high temperature shearing and strongly aligned microcracking, to cite just two examples. There are fierce debates regarding the seismic properties of minerals in the mantle and there are few specialized labs that can seismically test these unstable, high-pressure minerals.
For example, a mylenite can be a mineralogically isotropic rock type but has an distinctly aligned mineral fabric that may do strange things to sound waves when they pass through: reflection, refraction, and polarization come to mind. Without knowing of the existence of this mylenite, in this example, a seismologist might mistake this highly reflective mylenitized unit for something very different.
This is not just a minor detail of a rock property but an important component behind understanding seismic transmission and reflection for exploration geologists as well as mantle geophysicists.

what is a transverse isotropic rock?


How can I remove this drawer?

Question: My basement utility sink has a drawer underneath that I want to remove, but I can't figure out how to do it. In hopes of finding instructions, there are no vendor markings on it, and I've compared it to sinks available at places like Home Depot or Lowes without any luck. I've watched various YouTube videos about how to remove various kinds of drawers, but haven't found any quite like this one. Including some photos. In the last photo, I circled a plastic part. In many of the videos I saw suggestions to try moving around plastic tabs in order to remove the drawer, but this one doesn't appear movable.
Comment: With the full extension drawer glides that are used to support the basket and the way the basket covers all the possibility of releasing the drawer glides. (The one you have circled is not a release point, so I think) The basket will be required to be removed out of the way first,  since the release points for most full extension glides that I am aware of are on the side that is covered by the white metal base frame of the basket. The pictures given do not show enough detail under the bin or at potential release points to give direction.
Comment: the red circled component is a bumpet
Comment: I would look underneath, or outside the (fully extended) rails for something you can push in order to release the basket.  A photo of the outside of the rail would be helpful.  Good luck!
Answer: I believe if you pull the drawer out as far as it will go, and look on the side of the rails you will see a little lever   That leaver must be held down on one side and up on the other (Or vise-versa) and the drawer will be released to be pulled out.  You MUST hold the levers up and down before the drawer is pulled or they may bind.  It helps to have someone help you.
Answer: It seems you have access to all mounting screws through the basket.
With a screw driver or long drive bit you could remove the gliders from the cabinet, rather than attempt to separate the gliders or remove the basket from the glider.

How can I remove this drawer?


The divisor function and number of divisors.

Question: Prove $\sigma$(n) $\equiv$ $d(n)$ mod 2 where $\sigma(n)$ is the divisor function and $d(n)$ is the number of divisors of n.
So, this is equivalent to saying that $\frac{\sigma(n)}{d(n)}$ $\equiv$ 1 mod 2.
So I just have to show that the fraction of $\sigma(n)$ and $d(n)$ is odd. We know that $\sigma(n) = \prod\sigma(p^{a_{i}}_{i})$ for each $p^{a_{i}}_{i}$ in the prime factorization on n. I also know that $d(n) = \prod(a_i + 1)$ for each $a_i$ in the prime factorization of n. So this will yield $\prod\frac{\sigma(p^{a_{i}}_{i})}{a_i + 1}$. I'm not quite sure how I'm able to simplify this further or manipulate it.
Answer: If I understand your proposed theorem correctly, it is not true. I am assuming you mean the sum of divisors function by $σ(n)$. As a counterexample, $σ(2)=3$ and $d(2)=2$. However, your theorem is true for $n$ with an even number of 2 factors, or, in other words, for odd $n$ or $n$ divisible by 4. In fact, your proposed theorem is false in all other cases ($n$ divisible by $2$ but not by $4$).
I don't see any motivation for the fraction approach. I would just write this out explicitly.
Let $n$ = $2^mp_1^{e_1}*\cdots*p_k^{e_k}$. Then
$$σ(n)=(1+2+\cdots+2^m)(1+p_1+\cdots+p_1^{e_1})*\cdots*(1+p_k+\cdots+p_k^{e_k})$$
This has $(e_1+1)*\cdots*(e_k+1)$ odd terms, which is precisely the number of odd divisors of $n$. If $m$ is even, then the total number of divisors of $n$ is an odd multiple of the number of odd divisors. Thus, for odd $m$, $σ(n)$ is odd iff $d(n)$ is odd.


Is transferring to another university an option for an unhappy PhD student?

Question: I've heard of people transferring between graduate schools because of their advisor moving to another school and taking their students with them.
Do students ever transfer for other reasons? If a student isn't happy at the school they choose, could transferring be an option? Presumably they would frame it as something positive such as "turns out I really want to work with Professor X" rather than "I hate my school", but does this ever happen? Is there a certain timeframe in which this is possible? (Assume it's a 5 year PhD program.)
If the answer varies by subject please mention the subject in your answer.
(Context: many friends have told me that if it turns out I'm not happy with my choice, I can always transfer. My impression is that this is actually difficult since many schools don't accept transfer students and in any case not being able to stick with a program looks bad -- but I don't have evidence either way so wanted to ask people who are in academia. Of course the ideal would be to pick a school one is happy with in the first place!)
Comment: I know "transfers" of two kinds: 1) starting a new PhD program 2) formally being enrolled and one place but de facto collaborating a lot with another place. Sadly, one of the biggest pains in doing PhD is that when things aren't working you cannot just change places.
Comment: Related: https://academia.stackexchange.com/questions/23170/my-department-is-not-concerned-with-publishing-is-this-a-valid-reason-to-move-t
Answer: Mathematics
Let me specify that by transferring, I mean moving to another university in the middle of a graduate program.  Switching universities between undergrad and grad or between a master's degree and a Ph.D. is very different.  Basically, those are the only mainstream opportunities to move, and anything else will require an exception.
Transferring is certainly not unheard of, but there are some serious caveats:

It's difficult to transfer to a substantially more prestigious department.  It can happen, but the admissions committee will be very skeptical, and it's just not going to work out unless the application is outstanding.  In particular, many committee members specifically do not want to reward rolling the dice again and seeing what happens, so for transfers the question is not "Does this application look better than our weaker students?" but rather "Is this application so obviously wonderful that we would be shooting ourselves in the foot if we accepted someone else instead?"
Expressing any unhappiness will make it much harder to transfer.  You may think you'll be happy at the new school, but they will worry about ending up with an unhappy, unproductive grad student on their hands.  And they are right to worry about that: the best predictor of future happiness is past happiness, and many unhappy people have unrealistic beliefs about what would make them happy.
It's hard to transfer once you start seriously working on a thesis.  If your work isn't going well, then that's a reason not to accept you.  If your work is going well, then that's a reason you should continue working with your current advisor.  Unless your advisor has died or left, it will be tough to convince anyone you are a good candidate for transferring.
No matter why you say you want to transfer, there will be some suspicion that your goal is to end up in a stronger department or a more desirable location.  If you have another reason, you'll have to make a powerful argument for it.

I've heard of people transferring between graduate schools because of their advisor moving to another school and taking their students with them.

Sometimes they transfer officially, and sometimes they still get degrees from the previous school but complete their theses while in residence at the new school.  The latter is generally easy to arrange when an advisor moves.
Comment: "No matter why you say you want to transfer, there will be some suspicion that your goal is to end up in a stronger department" -- assuming the candidate is suitable for the "stronger department", why would the admission committee see this motivation as something negative?
Comment: @Pandora: It's not so much that it's negative, but that the committee may not believe other reasons.  Applicants sometimes outline personal or intellectual reasons why they feel a certain department would be a much better fit for them, only to have the committee basically ignore the stated reasons on the grounds that they are just an excuse.
Comment: @AnonymousMathematician what if they accepted you and offered you an assistantship, but then you wound up choosing somewhere else? Would the place you turned down be more inclined to accept you as a transfer?
Comment: I have transferred during my PhD to a far better institution and it was one of the best decisions I've ever taken. On points 1 and 2 above:
1. I agree that the admission committee will likely to be skeptical. Get in touch with a potential supervisor first or detail why you are transferring in a cover letter.
2. If you share the reasons you're unhappy we can help you formulate them. Remember that the potential supervisors likely know your current one and no supervisor wants to be known for stealing other people's PhD students. Balancing transparency and political correctness is key here.
Answer: Computer Science
Yes, PhD students transfer for many reasons besides moving advisors.  Sometimes the reasons are purely professional; for instance, I've seen several students successfully transfer because they  discovered a passion for a subfield that didn't match the interests/experience of the local faculty.  Sometimes they're more personal things like two-body problems (especially when they become three-body problems).  Sometimes advisors die or leave academia.  Sometimes it's because of an irreconcilable disagreement between student and advisor/committee.  Sometimes the student just thinks they can do better than their current department (and has the publications to prove it).
Probably the most painless time to transfer is immediately after completing a master's degree.  (I did this.)  That's a natural time to switch research directions, and many PhD programs allow their students to pick up a Master's degree along the way, even if they don't have a separate Master's program.  (Mine didn't.)
Still, applications from MS students in PhD departments will face skepticism, especially if the applicant already has a good track record with their former advisor.*  (Why do they want to leave their current advisor?  Shouldn't we offer this slot to someone who doesn't have one?)  So it's important for the applicant's research statement to explain why the new department would a better match, without disparaging the old department.  It's also important to have a strong and supportive recommendation letter from the former advisor, to address possible concerns about technical weaknesses or personality conflicts.
(*And if a PhD applicant doesn't have a good track record with their MS advisor, they're not likely to be admitted anyway.)
Answer: Field: Mathematics.
Transferring is possible although you might have to 'start over' at your new university. For example, perhaps you have completed the first year sequence of courses in University A and passed some prelims before transferring to University B. At University B you might either be required to go through their first year sequence, or take (and pass) the relevant prelims to have the courses waived. This can be difficult since first year courses and topic and prelims tend to vary across departments. In addition, depending on how much prior experience you have before coming to University B, they might require you to finish your degree in less than usual time (say, 3-4 years instead of 5). In particular, folks with Masters degrees applying to PhD programs are often required to get a second Masters in their second university.
Source: A friend of mine transferred from Rice Mathematics to UW Madison Mathematics; additionally this was a topic of conversation at a Nebraska Conference for Undergraduate Women  in Mathematics where a breakout session leader had transferred universities mid-PhD.
Comment: _In particular, folks with Masters degrees applying to PhD programs are often required to get a second Masters in their second university._ — Interesting.  My university explicitly forbids duplicate degrees.  If you have an MS in mathematics, you _cannot_ get another MS in mathematics (although you can get an MS in, say, computer science).
Comment: I haven't heard of being required to get a second Master's degree (many programs don't even require one in the first place), but prelims/required courses can definitely be an issue.
Comment: The specific instances I have seen of students being required to get a second Masters degree are not in mathematics. In particular, the students in question had masters degrees from India and were required to get second masters degrees as part of their (5 year) PhD programs in Psychology and Engineering - possibly in part because the masters degree is somewhat synonymous to candidacy and/or skepticism about degrees from other countries.
Answer: Computer Science
It's not uncommon for a student to transfer, usually earlier in the program. The reasons can be as you mentioned, and often there are non-academic reasons as well.
You do have to apply again from scratch, although its possible that admissions committees will look more generously on the application. You might be able to apply out of cycle for spring admission as well - there are fewer applicants and each application gets more careful scrutiny.
But in any case it is important to have a reason relating to the desired destination. If you want to work with professor X it will help immensely if professor X can speak on your behalf by writing a letter. In other words, don't think of transferring out, but think about transferring in to maybe one or two targeted placed.
Answer: I am currently trying to transfer too. My story isn`t the nicest neither. I met one guest speaker at my current university and just loved her work. My lab is stacked in old technologies and I feel we aren't innovative at all.
I talked with this guest speaker and her answer was very positive regarding getting me as her student. However she asked me to tell my supervisor before applying: bad idea.
Maybe because I am in Asia and here the culture is that your professor is a God, he was really unpleasant and rude with me. He even said he would write bad recommendation letters for me if I change universities. For me that was harassment. His main reason was the money invested and how bad this looks for him and for the university.
My advise is: be sure you can move and then talk with your adviser. The only positive thing was that after talking with him, I was certain that I was at the wrong place. I am positive I can change. So if you aren't happy or the program isn't aligned with your future goals and perspectives, change! Don't waste your time.
Comment: I see the anecdote and its connection, but I'm not entirely sure that I see this as an answer to the question.
Answer: I transferred during the first year of my PhD program successfully. My project at my original department was fully funded and my adviser was also great. However, I did not like the department and my PhD major was not in line with my interest. Thus, I applied for another major which I liked more.
One problem that may arise is recommendation letter. I asked my MS adviser (in another school) to write letter. I also asked my PhD adviser for recommendation letter. This part is a bit tricky, but I suggest to be honest and tell the truth and provide detail explanation for your decision.
I talked with 4 faculty members about my application in a conference. Three of them did not have any problem whatsoever with the fact that I am a PhD student from another school, and they recommended me to apply whereas one of them told me that the department does not accept transfer student. I finally got admitted into one school. I applied from a mid-rank school to top rank schools.
My personal view is that there is nothing wrong with transferring from one school to another, but you should have a good reason for doing that. In any case, some faculty members understand that a student could have many reasonable reasons for moving away from a school and joining another one while others are not very open-minded and think that it is wrong.
Answer: Selection of graduate students is hard.
It's fine to switch programs, but it's a lot like switching jobs after a short period.  If you start a job somewhere, then immediately leave it, you need a decent reason in your narrative.  The program you're applying to needs to believe that you're interested in sticking around when crunch time comes, or you're not worth the investment.
It helps if you have a legitimate-sounding reason in your personal statement that makes it sound like the reason you left the previous institution is unlikely to recur.  It definitely helps if you have an LOR from your former advisor.
Comment: What about, say, transferring from a Math Education PhD program into a regular Math PhD program, because you realize that doing research in pure mathematics is where your heart really lies, and not in doing research on how best to teach it to other people?
Comment: I realize this is an ancient question, but I think it's a lot more defensible if you are changing programs entirely like you mention. It's not uncommon for someone in the grad-school path to shift gears because they discover something they are more passionate about, and passion is exactly what your selectors want to see evidenced. If you can convince them "I like this even more" rather than "I'm bored", then that is a positive.
Answer: Science (chemistry).
It is very hard, up to impossible, to change PhD program in science after you started one, as well as starting over after a failed attempt.
The only option is before you enroll in any.
Even if this is not directly stated in requirements, selection comity will be very suspicious and very unlikely to admit such a student.
For the most part already enrolled applicants or applicants that were enrolled and quit are not considered eligible be programs and in almost all cases you are not eligible to apply for a scholarship.
I now as I am trying to change the PhD program.
Answer: Molecular Biology
The only time I can think of when PhD students changed universities was on the unexpected death of their advisor.  In that case, former students of the advisor who had since started their own labs took on the students, in some cases temporarily until they could find a better fit, in other cases until graduation.  For the "better fit" cases, I believe both student and new supervisor approached the better-fit lab and explained the situation.
In the case I'm thinking of, the deceased advisor was very well known, came from a highly prestigious university, and had many former students in strong positions.  I don't know how well it would have worked if all those points were not the case.
Aside from that instance, it's very rare for PhD candidates to move locations without your advisor moving as well.


Philosophy king and sage rule

Question: The concept of philosophy king seems to be somewhat similar to the Taoist doctrine of sage rule. Taoism has very high requirements for the virtues and realm for the ruler and the people, requiring the ruler to do nothing but do everything(wu wei无为而治) , and the best ruler should be so that the people know of his existence but cannot feel his influence, and his rule is like the spring breeze that turns into rain and moistens things silently. And the people are like children who know enough and are happy, simple and honest. However, all this envisages are base on people's moral quality is that actually feasible? There is another question, a saint in Taoism would not want to be a dominator? Is plato also has same question?
Comment: Your "Very high requirements" reminds me of [Marlon Brando](https://www.youtube.com/watch?v=fgvMPUcw_2Q). I knew a [man](https://philosophy.stackexchange.com/a/108144/37256) who, as best as I could see, was very close to God.  At no point did I ever see him see himself as special/different/above the rest.  In any case +1. May you find an answer!
Answer: Mainly in his work "Republic" Plato published his opinion on politicial philosophy. Plato composes a political utopy where his teacher Socrates designs a state according to Plato's philosophical ideas. Plato lets Socrates say (Greek, English):

ἐὰν μή, ἦν δ᾽ ἐγώ, ἢ οἱ φιλόσοφοι βασιλεύσωσιν ἐν ταῖς πόλεσιν ἢ οἱ
βασιλῆς τε νῦν λεγόμενοι καὶ δυνάσται φιλοσοφήσωσι γνησίως τε καὶ
ἱκανῶς, καὶ τοῦτο εἰς ταὐτὸν συμπέσῃ, δύναμίς τε πολιτικὴ καὶ
φιλοσοφία, τῶν δὲ νῦν πορευομένων χωρὶς ἐφ᾽ ἑκάτερον αἱ πολλαὶ φύσεις
ἐξ ἀνάγκης ἀποκλεισθῶσιν, οὐκ ἔστι κακῶν παῦλα, ὦ φίλε Γλαύκων, ταῖς
πόλεσι, δοκῶ δ᾽ οὐδὲ τῷ ἀνθρωπίνῳ γένει, οὐδὲ αὕτη ἡ πολιτεία μή ποτε
πρότερον φυῇ τε εἰς τὸ δυνατὸν καὶ φῶς ἡλίου ἴδῃ, ἣν νῦν λόγῳ
διεληλύθαμεν. (Book V, 473c-e)
"Unless," said I, "either philosophers become kings in our states or
those whom we now call our kings and rulers take to the pursuit of
philosophy seriously and adequately, and there is a conjunction of
these two things, political power and philosophic intelligence, while
the motley horde of the natures who at present pursue either apart
from the other are compulsorily excluded, there can be no cessation of
troubles, dear Glaucon, for our states, nor, I fancy, for the human
race either. Nor, until this happens, will this constitution which we
have been expounding in theory ever be put into practice within the
limits of possibility and see the light of the sun."

Here a philosopher advances and supports the idea, that either the members of his own class become rulers or the kings of the states become philosophers.
Plato's state is totally different from a democratic system, it is a totalitarian system. The philosopher Popper condems Plato's "Republic" in the harshest of terms in his own book "The Open Society and Its Enemies".
Plato himself made some attempts to implement his political philosophy in the government of the city of Syracuse (Sicily), but without success.
A late voluminous work of Plato's political philosophy are the 12 books The Laws.
Answer: I dunno about Tao ways of doing or thinkin' on things.
If there were individuals worthy of the title "philosopher king"... the last thing they would want is a crown to weight their head down and force them to think on things that mattered little to them.
Better to live and let live, rather than become target of drama and scrutiny.  Be an informer, a teacher, a provider of knowledge, rather than take responsibility for.
When asked to be the ruler of Isreal... Einstein was smart enough to politely say "No Way, but thx for askin'" (I paraphrase).
Those that would agree to rule, largely give away their freedom to choose exactly what they want to think about.

https://www.britannica.com/story/the-time-albert-einstein-was-asked-to-be-president-of-israel
Answer: The principles of philosophy -- to think clearly about thinking and reasoning, about morality, and about the connections between things, would be very useful in a "ruler".  There is some justification to think that a philosopher would be a good ruler/leader.
However, there are other aspects of philosophy that would be a serious detriment.

The core of the philosophic mindset is to question the boxes we think within.  This leads to a lot of potentially very useful "but what if" and "but what about" questions that any leader/ruler should ask.  BUT -- often the answers, when you push these questions to their limits, are that we don't know for sure.  This can lead to paralysis by analysis, where pursuing the "nth" degree justification is done before acting.  It is the nature of human social dynamics that there are regular crises that need quick decisions, and philosophers are generally not well mentally constituted to do this.  This aspect of philosophy makes sages/philosophers much better ADVISORS to a ruler/leader, than rulers/leaders themselves.
Philosophy is a very abstract activity, and as a practical matter, most philosophers end up adopting a very counter-intuitive abstract worldview.  There is an allure in philosophy to prioritize abstract theory over practical experience.  But running a human enterprise is a VERY pragmatic problem. Leaders/rulers who adopt an abstract theoretical construct, are most accurately described as being "in the grip of an ideology".  Philosophers are particularly susceptible to ideologies, given their prioritization of theory over pragmatism.    This was what Karl Popper critiqued about Plato, and Marxist theory, etc. in his works that argued for a pragmatic Open Society.  With so many actual philosophers in the grips of ideologies, philosophers as a class are a suspect pool to draw leaders from.

Philosophy king and sage rule


How to automate Lightswitch for metaprogramming

Question: I really like the Ria Services approach, and I see Lightswitch as the next higher level of abstraction, but my scenario is this:
I need to be able to define a Lighswitch app without having to rely on the designer and tedious click-throughs. If I have access to the API that the designer uses, then I can automate application generation, I can parameterize it and apply custome logic for generating custom variations of the same application type,  I can even wrap it within a DSL. As a programmer, I want to levarge Lightswitch for developing applications by meta-programming.
I'm a programmer. Whilest I can use  the "Write Code" dropdown to insert code blocks into the Application, ApplicationDataService, EntityObject and ScreenObject classes, I would like the ability to define entites, screens, relationships and queries through code / markup / a DSL.
Obviously Lightswitch meta-programs this when I use the designer, but I would like to do it myself. What I would like to accomplish is to create a lightswitch app - without having to click through a tool or designer. In Lightswitch, the pieces are obviously there (the designer leverages them), but they are not exposed as a public API. being a plugin for visual studio, perhaps there is a VSIX API extension I can leverage for automating Lightswitch? Show me some code.
Answer: The LS team have not yet released any official API information. As you may know however, all of various data/query/screen definitions exist in the ApplicationDefinition.lsml file, located in the LS project's "Data" folder.
I would hope that API information will be made available once the RTM has been released.
Yann


How to connect a DC socket to a switch

Question: I have a basic flip switch that I want to use to control whether a DC power socket is providing energy (from a connected battery pack). The power socket has three prongs, the switch has three, and there are the normal two wires (red and black) coming from the battery pack. What I'm not sure about is how to wire the three together so that when the switch is in one position the socket provides power (from the battery pack) and when the switch is in the other position the socket does not. For both the switch and the socket one prong is obviously in the center and the other two are indistinguishable.
Comment: Can you provide some part numbers, or at least some pictures of the parts in question?
Answer: While you don't provide a picture or part numbers for your dc socket or switch, these are common enough parts that general information works.
I am assuming your DC Socket looks like this:

And your switch is generally like this:

The socket has three prongs. One for the center, this is normally the one on the rear. One for the barrel, which is normally the one on the bottom, and the middle one is actually a switch, so that if you don't have a plug inserted, it can provide an alternative path.
The two you are interested in are the rear and bottom ones. It varies if the center is positive or negative, that depends on your battery pack.
As for the switch, a three prong switch is usually a SPDT (Single Pole Double Throw). The image above shows how it is commonly set up. The center prong acts as a common pin, while A and B are the switch. Flip to one side A is connected to Common, flip to the other, B is connected to the common.
To act as a single power switch, you would want to connect one prong of dc socket to the Common prong of the switch, and the rest of the circuit to A (or B), leaving the other one empty. When you flip it to A, the connection is made to the socket, and power should flow. When you flip it to B, the connection is broken (Nothing being connected to B), giving you a power switch.
Answer: I'm somewhat confused, a picture might help. Here's my best effort to piece it together. Use a multimeter to determine what is what. Set the meter to measure DC voltage and measure the voltage between each pair of prongs on the three prong socket. If you measure something like 0V between two pins it's a pretty good bet that two of those prongs are electrically equivalent. If you are able to separate the battery pack from the socket, you can verify this with the continuity or resistance setting of your multimeter (ringing or less than an ohm or two of resistance is a positive indication of electrical equivalence). The two prongs that measure as the positive battery pack voltage (with the battery pack attached) tell you which  pair are the positive terminal and negative terminal respectively. If you can remove the battery and use the resistance continuity setting to determine which prong rings to which battery lead (red/black), all the better. Black is called ground (GND).
Basic idea with the switch is to have it break the black battery terminal with the switch. If current can't reach GND the battery won't provide power to anything.

How to connect a DC socket to a switch


Distance from point to line in three dimensions

Question: Say the equation of a line is given by the parametric equations $x=x(t), y=y(t), z=z(t)$, then
$$r(t)=x(t)\vec{i}+y(t)\vec{j}+z(t)\vec{k}$$
can be reduced to $$r(t)=r_0+t \begin{bmatrix} a \\ b \\ c\end{bmatrix}$$
where $r_0$ is the initial point the line passes through and the vector with components $a,b,c$ is direction vector of $r$.
Now I want to find the shortest distance $d$ from the line to the point $P_1(x_1, y_1, z_1)$ outside of this line. I'm able to find the direction vector of $d$, which I think is $\begin{bmatrix} x_1-x_0 \\ y_1-y_0 \\ z_1-z_0  \end{bmatrix}$ but I'm not able to take it any further to find $\Vert d\Vert$.
Comment: What you have found is not direction vector of $d$ but direction vector from $P$ to the given point on the line. Now, do a cross product with the normalized direction vector of the line. The magnitude gives you the shortest distance.
Comment: Or you can take any arbitrary point on the line $(x_0 + at, y_0 + b t, z_0 + ct)$ and find vector from $P$ to this arbitrary point. Now if it is shortest distance to the line, the vector would be perp to the line so the dot product of the vector with the direction vector of the line will be zero. Once you solve for $t$, you get the point on the line which has shortest distance from $P$. You can then find distance using formula for distance between two points.
Answer: The distance from the point $(x_1, y_1, z_1)$ to an arbitrary point of the line satisfies  $$ D^2 = (x_1-x(t))^2 + (y_1-y(t))^2 + (z_1-z(t))^2$$
You want to minimize this function.
Take the derivative with respect to $t$ and let the derivative equal zero to find the $t$ which gives you the shortest distance.


Asking should cost reputation if never upvoted

Question: A lot of questions receive very little attention, and as such are very likely uninteresting to anyone but the author. At the moment there is no incentive for authors to revise or delete such questions (even after the author is no longer interested in an answer), which means there'll be an ever increasing amount of such questions over time. As an incentive for users to clean up old questions which didn't receive any attention, there should be an initial cost to posting a question, which could then be reimbursed when upvoted for the first time, or when the user deletes the question.
Comment: So, if I see a label "restaurant" I might go into a "cinema" ? the tooltip should change obviously!
Comment: This is why the permissions mechanism permits higher-rep users to do the cleanup for the site.
Comment: "Being stupid should hurt."
Comment: @JorgePinho: [Downvotes are different here](http://meta.stackoverflow.com/faq#vote-differences)
Comment: If every user was an **active** user this would not be an issue.
Comment: @l0b0 Really ? thats not what the arrows say...
Comment: @Jorge Pinho: [Related meta question](http://meta.stackexchange.com/questions/75049/change-upvote-downvote-tooltip-on-meta-sites)
Comment: @Jorge [See this question](http://meta.stackexchange.com/questions/75049/change-upvote-downvote-tooltip-on-meta-sites) regarding changing the tooltip.
Comment: why the downvotes ? this is a legit opinion.. (even if you dont agree)
Comment: @MichaelTodd: This isn't about being stupid. It might just be that the question is too niche for anyone to care to answer, but not so much as to be eligible for closing.
Comment: @all (downvote != disagree) && (upvote != agree) in my (language, heart, mind)
Answer: I disagree.

Bad questions should cost, and they do: bad questions should be downvoted.
Good questions should be rewarded, and they are: upvoting

Now questions with little attention might be niche-questions, which can be either good or bad: if there is only a small portion of people looking at it, they will not get any votes, but that doesn't mean the question should be revised or deleted as far as I'm concerned.
Questions that are uninteresting because of their content/the way they are asked instead of the topic, should be downvoted, which will give you the desired result?
Comment: I agree with your answer **?**
Answer:
A lot of questions receive very little attention, and as such are very
  likely uninteresting to anyone but the author ... there is no
  incentive for authors to revise or delete such questions ... which
  means there'll be an ever increasing amount of such questions over
  time

Tumbleweeds get swept up
The questions you're describing get auto-deleted after a year, so there won't be an ever increasing amount of such questions over time.
Here's the rules from the linked answer

If the question is more than 30 days old, and ...

has -1 or lower score
has no answers
is not locked

... it will be automatically deleted.
If the question is more than 365 days old, and ...

has a score of 0 or a score of 1 with a deleted owner
has no answers
is not locked
has a viewcount <= the age of the question in days times 1.5
has 1 or 0 comments

... it will be automatically deleted.

Not getting an answer should be enough of an incentive to improve a question.
Comment: Awesome; I had no idea.
Comment: As a first time user in SE, I had a bad experience, due to the voting arrows mean diferent than their own tooltips!
Comment: @Jorge I'm sorry to hear that. If it helps [you're not alone](http://data.stackexchange.com/meta/query/61240/)
Answer: Most poor questions are asked by first time users.  First time users don't have reputation (currently you can't go negative) to decrement in order to ask.  It would also present a negative experience when first encountering the system.  Further a good question could be "punished" simply because it's hard or doesn't attract any attention.  I've had a few that have languished for awhile before getting an answer.
There are already structures in place to help improve questions: editing, "free" downvotes on questions, closure, comments, etc.  I don't see where this is an actual improvement.  I'd hate to see a situation where people are discouraged from asking because they know up-front that it will cost them.  I'd also hate to see questions deleted simply because they haven't attracted attention.  That, in itself, is not indicative that it is a bad question.
Comment: " I'd also hate to see questions deleted simply because they haven't attracted attention." [But they do get deleted](http://meta.stackexchange.com/questions/78048/auto-deleting-old-unanswered-zero-score-questions-after-a-year). It just takes a long time
Comment: @ConradFrix - I wasn't aware of that change.  But at least they leave the question open for a year.  If I could get rep back by deleting it, I would probably be less patient.
Answer: I don't think the lack of attention necessarily means lack of quality, because of this I see no reason to provide incentives to delete questions. Some good questions might be without upvotes because they are very complex and people are unsure about voting it up because they don't understand it completely (just an example, but it can happen).
Besides, a question that doesn't receive a lot of attention now, could be answered in the future (assuming it's legit, not off topic, NC, etc) and therefore still serve its purpose. What if I ask a very good question, no-one considers it, but after a while it gets answers and attention (for whatever reason)... Why should I be encouraged to delete it? That might lead to delete potentially good questions and therefore it would just cause the site to lose good content.
What I mean is that the lack of attention/upvotes, be it for one day or three months, doesn't necessarily make that question bad or dangerous.
That can be quickly established through comments, down-votes and Meta discussions about it. If a question deserves to be closed or deleted, it will be.
Lastly:

questions that just get closed, sometimes can be improved and reopened, so this further reduces the reasons to encourage users to delete their questions which lacked attention.
There is even a badge for your question that has lack of attention, the Tumbleweed badge.
Answer: I would sugest that a question should have a time limit defined by the poster, like such:
If no answer (and no upvotes) after X hours (or days): delete question
Dont forget that there is the "Peer Presure" badge!
Comment: Sometimes stackexchange feels like military (in a very bad way)
Comment: Deleting a question automatically (which is what I assume is meant here) is a terrible idea, firstly because users truly **hate** anyone who deletes their content without their explicit consent. If a timeout is set by the user, they will all set it to infinity. Also, sporadic users might come back much later and revise or add a bounty to get stuff fixed. I know I have done.
Comment: It would just be a feature: I can mark my own question for deletion if no answers and no upvotes
Comment: Don't forget that there is the [Tumbleweed badge](http://stackoverflow.com/badges/63/tumbleweed) too.
Comment: @JorgePinho: The way SO/E works there's no user incentive to set this less than infinity, other than tidiness in your own list of questions.


Missing Values Correlation

Question: Is it worth it to study missingness correlation between columns?
If you have strongly correlated missing values (say between two columns, A and B), how will this change or shape the way you look at data? Does it add new information when analyzing data? Or, influence the analysis you would perform on it?
Answer: Usually the term correlation is used in context of association (and very often linear association). e.g. the daily price of stock A is highly correlated with the SP500 index. I am guessing here that you are thinking of occurrences of missings. e.g. How often when column A is missing is column B missing? Or When column A is missing does column B have specific values. And bring in other columns, when A and B are missing, then C is always > 100.
My answer is yes. Understanding the data, building more interactions into the data, going back and getting better data or questions why about the data are always good things.  If 90% of the time that col A is missing then col B is missing also, this is a good question to look at how the data was acquired. Maybe use or not use the data. Maybe build indicator variables or interact the 2 columns, etc.
The more effort you put into the data, the better chance that the model has to be successful. It is good you are thinking about how to get creative analyzing your data.
Answer: Yes, studying missingness correlation between columns is valuable. It can reveal systematic reasons for missing data, suggest hidden relationships between variables, guide strategies for imputing missing values, and indicate potential bias in the dataset. This information can influence your analysis and preprocessing steps before modeling.

Missing Values Correlation


Population Growth mathematical modelling?

Question: Hey guys I'm struggling to find much information of modelling single species population dynamics that relates to this question. A question like this is going to be coming up in my final exam and I need to be able to solve it. I'm struggling to even know where to start. I'm completely new to modelling populations. help would be much appreciated.

A population, initially consisting of $M_0$ mice, has per-capita birth rate of $8 \frac{1}{week}$ and a per-capita death rate of $2\frac{1}{week}$. Also, 20 mouse traps are set each fortnight and they are always filled.
(a)Write down the word equation for the mice population $M(t)$.

$$\Bigg(
\text{Rate of change}
  \text{ of number of mice}
\Bigg) = \Big(\text{Rate of Births}\Big)-\Big(\text{Normal rate of Reaths}\Big) - \Big(\text{Rate of deaths by mousetraps}\Big)
$$

(b) Write the differential rate equation for the number of mice.

$$\dfrac{dM}{dt} = 16M - 4M - 10$$ $$M(0) = M_0$$

(c) Solve the differential rate equation to obtain the formula for the mice population $M(t)$ at any time $t$ in terms of the initial population $M_0$

The differential equation I've got is $$\frac{dM}{dt}= 12M -20$$
I don't know what method to use to solve this, I can't figure out if the model is logisitc or some other type.

(d) Find the equilibrium solution $M_e$

I found online that Equilibrium solutions are found by setting
the derivative equal to zero and solving the
resulting equation. I'll be able to figure that out later once I solve (c)

(e)Find the long-term solution with the dependence on $M_0$. What happens when $M_0 = M_e$

No idea what's being asked here. I can't seem to find any information. It doesn't help that there is no decent books about this online that can be found easily.
thanks for all the help.
Comment: You have a separable differential equation there.  Do you know how to solve that class of equations?
Comment: What type of model is this?
Answer:
(c) Solve the differential rate equation to obtain the formula for the mice population $M(t)$ at any time t in terms of the initial population $M_0$

So from your help I solved the separable differential equation. The final result I got was $$M(t) = \dfrac{e^{12t+12c}+20}{12}$$ The question is asking for it in terms of initial population $M_0$. We know that $M(0)= M_0$. Therefore
$$M_0 = \dfrac{e^{12c}+20}{12}$$
Is this what they mean by "in terms of the intial population $M_0$"? Thanks :)


What does "dolphins ... get second billing" mean?

Question:
The dolphins had deduced, correctly, that they would get second billing.

What does this sentence mean? Is "second billing" an idiom of some kind?
Comment: Here, "billing" has its Broadway/Hollywood sense: how an actor or star's name appears in the beginning/ending credits of the work, on the marketing materials, promotional posters, theatre marquees, etc. "Second billing" means someone else is getting "top billing", or more attention/credit.
Comment: Is this a quote from Douglas Adams?
Comment: It is From odyssey 2:2010
Answer: Dan Bron pointed out the essential answer more than a year ago in a comment beneath the poster's question:

Here, "billing" has its Broadway/Hollywood sense: how an actor or star's name appears in the beginning/ending credits of the work, on the marketing materials, promotional posters, theatre marquees, etc. "Second billing" means someone else is getting "top billing", or more attention/credit.

Don Wilmeth, The Language of American Popular Entertainment: A Glossary of Argot, Slang, and Terminology (1981) has this entry for billing:

Billing: 1. The ranking or mention of a performer's name in a show's ads or notices, which are displayed inside or outside a theatre or other place of entertainment, or distributed by hand. Top billing is a holdover from vaudeville in which the main attraction would be listed in the top of a bill of a program of  number of acts, eight being the usual number. After top billing, an act, especially a new attraction, would prefer bottom billing, which was considered by many the first indication of success or recognition for virtual unknowns. [Cross reference omitted.] 2. Also the name for the notice or advertisement for a production or show.

So according to Wilmeth, in the old days of American vaudeville, "top billing" was best, "bottom billing" was second best, and "second billing" was nowhere to be found. In modern usage, however, "bottom billing" seems to have lost its sense of being a desirable spot on the bill, while "second billing" has emerged as a kind of consolation prize for the non-diva not-quite-headliner.
The intricacies of promotional billing in the modern (in 1964) film industry are the subject of Peter Bart, "Billing Without Cooing: Whose Name Goes Where in Screen Credits Is Still A Most Important Ploy for Hollywood Luminaries" (November 15, 1964) [combined snippets], reproduced in Gene Brown, The New York Times Encyclopedia of Film: 1964-1968 (1984):

Though this sort of compromise sometimes can be reached, many stars drive as hard a bargain as they can in each picture they make. In "Invitation to a Gunfighter" for example, Yul Brynner not only received the contractual right to have his name carried in all ads in the same type sue as the title of the film but also to decree the size of everyone else's name (Janice Rule was his co-star). In "Morituri," however, Brynner had to take second billing to Marlon Brando, a star who will never deign to occupy second place.
Out Alone
Elvis Presley, like Brando, flatly declines to take second billing and, in addition, refuses even to share the space over the titles in movie ads with any other performer. His name must stand alone above the name of the picture.
...
Many contracts for stars like Cary Grant or Rock Hudson stipulate not only the size of type but also its thickness, style and position. They also decree that the star's picture must always appear on the left side of the ad and that it must be larger than the picture of any other star. Agents for the fast-rising young , felt they had pulled off quite a coup recently by inducing Presley to make an exception and allow her name under his above "Viva Las Vegas."
...
Many supporting actors when denied top billing ask for special phraseology that will aid their status. In "The Loved One" Sir John Gielgud is listed as a "special guest star." In "Charade," Walter Matthau is listed as "co-star" but below the title and in notably smaller type than Cary Grant and Audrey Hepburn. In "I'd Rather Be Rich," Sandra Dee, Robert Goulet and Andy Williams are listed above the title while "Maurice Chevalier as Philip Dulaine" is listed in equal type below.

In the figurative sense in which Arthur Clarke uses second billing in 2010: Odyssey Two, the dolphins are not vying for the most prominent place on a placard announcing a theatrical production, but they do want paying attention to and they don't appreciate being a minor diversion:

Charming though they [the dolphins] were, he [Floyd] had to admit that their playfulness was sometimes a nuisance. ... But there had been one unforgettable occasion when the entire Board of Regents, in full evening attire, had been sipping cocktails around the pool while awaiting the arrival of a distinguished guest from the mainland. The dolphins had deduced, correctly, that they would get second billing. So the visitor was quite surprised to be greeted by a bedraggled reception committee in ill-fitting bathrobes—and the buffet had been very salty.


How to insert image inline, in email composed with OWA?

Question: When I am composing an email message in OWA 8.1.359.2, how do I insert an image in the body of the email, inline with text (not attachment)?
Answer: SOLUTION to copy and paste!! (Via Ctrl+C & Ctrl+V) (ok so its a good idea to have Exchange 2007 SP1 Rollup 7 pre-installed)
FROM inside OWA (exchange 2007 - I have sp3 on my exchange servers' servers) go to options and email security and then install the Outlook web access s/mime control program works in XP and Windows 7 x64 workstation.
after install click save (probably does not but it does not hurt)
go back to new mail and you can now paste stuff off the clipboard.
This will also enable sending the previous mails as an attachment in a new mail (via drag & drop)
Comment: Vytor31's answer is correct. Here is a link to step by step instructions on installing/enabling the S/MIME control which allows copy and paste of inline images. [http://techthinking.net/2011/01/how-to-add-or-insert-pictures-in-outlook-web-access/](http://techthinking.net/2011/01/how-to-add-or-insert-pictures-in-outlook-web-access/)
Answer: In order to insert an image into the body of an email, you will have to declare the message MIME type to be text/html. Then, your attachment image as image/[IMAGE TYPE] (depending on the type of file) with the added header field of Content-Disposition: attachment; filename=[IMAGE FILENAME], and then refer to the image using the relative filename in the HTML:
Comment: any idea how to do the same (inline) for sounds and use then in javascript ? any tool?
Answer: Save your image anywhere on your PC, then right click and say Open with > Internet Explorer. Click and drag image into message window and voila.  Hope that helps! :)
Answer: If you are not using Internet Explorer, you can use the "Insert image" button in the first line of tools of the new message window.
In my setup, it is the third icon from the left, after the "send" link.
It's icon is the small mountain & sun.


Compilation to bytecode vs machine code

Question: Does compilation that produces an interim bytecode (like with Java), rather than going "all the way" to machine code, generally involve less complexity (and thus likely take less time)?
Answer: Yes, compiling to Java bytecode is easier than compiling to machine code. This is partially because there's only one format to target (as Mandrill mentions, though this only reduces compiler complexity, not compile time), partly because the JVM is a much simpler machine and more convenient to program than real CPUs — as it's been designed in tandem with the Java language, most Java operations map to exactly one bytecode operation in a very simple way. Another very important reason is that practically no optimization takes place. Almost all efficiency concerns are left to the JIT compiler (or to the JVM as a whole), so the entire middle end of normal compilers disappears. It can basically walk through the AST once and generate ready-made bytecode sequences for each node. There is some "administrative overhead" of generating method tables, constant pools, etc. but that's nothing compared to the complexities of, say, LLVM.
Comment: @Julian "middle end" is a real term, coined in analogy with "front end" and "back end" with no regard for semantics :)
Comment: You wrote "...middle end of...". Did you mean "...middle to end of..."? Or maybe "...middle part of..."?
Answer: A compiler is simply a program that takes human-readable1 text files and translates them into binary instructions for a machine. If you take a step back and think about your question from this theoretical perspective, the complexity is roughly the same. However, on a more practical level, byte code compilers are simpler.
What broad steps have to happen to compile a program?

Scanning, parsing and validating source code.
Converting source to an abstract syntax tree.
Optional: process and improve the AST if the language specification allows it (e.g. removing dead code, reorder operations, other optimizations)
Converting the AST to some form that a machine understands.

There only two real differences between the two.

In general, a program with multiple compilation units requires linking when compiling to machine code and generally does not with byte code. One could split hairs about whether linking is part of compiling in the context of this question. If so, byte code compilation would be slightly simpler. However, the complexity of linking is made up for at run-time when many linking concerns are handled by the VM (see my note below).
Byte code compilers tend not to optimize as much because the VM can do this better on the fly (JIT compilers are a fairly standard addition to VMs nowadays).

From this I conclude that byte code compilers can omit the complexity of most optimizations and all of linking, deferring both of these to the VM runtime. Byte code compilers are simpler in practice because they shovel many complexities onto the VM that machine code compilers take on themselves.
1 Not counting esoteric languages
Comment: Ignoring optimizations and such is silly. These "optional steps" make up a great deal of the code base, complexity, and compile time of most compilers.
Comment: In practice, that is correct. I was waxing academic here, I updated my answer.
Comment: Is there any language specification that actually forbids optimisations? I understand that some languages make it difficult, but not allow any to begin with?
Comment: @Davidmh I am not aware of any specs that _forbid_ them. My understanding is that most say that the compiler is allowed to, but do not go into any detail. Each implementation is different because many optimizations rely on details of the CPU, OS, and the target architecture in general. For this reason a byte code compiler would be less likely to optimize and instead punt that to the VM which knows the underlying architecture.
Answer: I would say that simplifies the compiler design since the compilation is always Java to generic virtual machine code. That also means you only need to compile the code once and it will run on any plataform (instead of having to compile on each machine). I am not so sure if the compilation time will be lower because you can consider the virtual machine just like a standardized machine.
On the other hand, each machine will have to have the Java Virtual Machine loaded so it can interpret the "byte code" (which is the virtual machine code resulted from the java code compilation), translate it to the actual machine code and run it.
Imo this is good for very big programs but very bad for small ones (because the virtual machine is a waste of memory).
Comment: I see.  So you think the complexity of mapping the bytecode to the standard machine (i.e. the JVM) would match that of mapping the source code to a physical machine, leaving no reason to think bytecode would result in shorter compilation time?
Comment: That is not what I said. I said mapping Java code to byte code (which is the Virtual Machine Assembler) would match that of mapping the source code (Java) to the physical machine code.
Answer: The complexity of compilation depends largely on the semantic gap between the source language and the target language and the level of optimization you want to apply while bridging this gap.
For example, compiling Java source code to JVM byte code is relatively straight forward, since there is a core subset of Java that maps pretty much directly to a subset of JVM byte code. There are some differences: Java has loops but no GOTO, the JVM has GOTO but no loops, Java has generics, the JVM doesn't, but those can be easily dealt with (the transformation from loops to conditional jumps is trivial, type erasure slightly less so, but still manageable). There are other differences but less severe.
Compiling Ruby source code to JVM byte code is a lot more involved (especially before invokedynamic and MethodHandles were introduced in Java 7, or more precisely in the 3rd Edition of the JVM spec). In Ruby, methods can be replaced at runtime. On the JVM, the smallest unit of code that can be replaced at runtime is a class, so Ruby methods have to be compiled not to JVM methods but to JVM classes. Ruby method dispatch doesn't match JVM method dispatch and before invokedynamic, there was no way to inject your own method dispatching mechanism into the JVM. Ruby has continuations and coroutines, but the JVM lacks the facilities to implement those. (The JVM's GOTO is restricted to jump targets within the method.) The only control flow primitive the JVM has, that would be powerful enough to implement continuations are exceptions and to implement coroutines threads, both of which are extremely heavyweight, whereas the whole purpose of coroutines is to be very lightweight.
OTOH, compiling Ruby source code to Rubinius byte code or YARV byte code is again trivial, since both of those are explicitly designed as a compilation target for Ruby (although Rubinius has also been used for other languages such as CoffeeScript, and most famously Fancy).
Likewise, compiling x86 native code to JVM byte code is not straight-forward, again, there is a pretty large semantic gap.
Haskell is another good example: with Haskell, there are several high-performance, industrial strength production-ready compilers which produce native x86 machine code, but to this date, there is no working compiler for either the JVM or the CLI, because the semantic gap is so big that it is very complex to bridge it. So, this is an example where compilation to native machine code is actually less complex than compiling to JVM or CIL byte code. This is because native machine code has much lower level primitives (GOTO, pointers, …) that can be easier "coerced" to do what you want than using higher level primitives such as method calls or exceptions.
So, one could say that the higher level the target language is, the more closely it has to match the semantics of the source language in order to reduce the complexity of the compiler.
Answer: In practice, most JVM today are very complex software, doing JIT compilation (so the bytecode is dynamically translated to machine code by the JVM).
So while the compilation from Java source code (or Clojure source code) to JVM byte code is indeed simpler, the JVM itself is doing complex translation to machine code.
The fact that this JIT translation inside the JVM is dynamic enables the JVM to focus on the most relevant parts of the bytecode. Practically speaking, most JVM optimize more the hottest parts (e.g. the most called methods, or the most executed basic blocks) of the JVM bytecode.
I'm not sure the the combined complexity of JVM + Java to bytecode compiler is significantly less than the complexity of ahead-of-time compilers.
Notice also that most traditional compilers (like GCC or Clang/LLVM) are transforming the input C (or C++, or Ada, ...) source code into an internal representation (Gimple for GCC, LLVM for Clang) which is quite similar to some bytecode. Then they are transforming that internal representations (first optimizing it into itself, i.e. most GCC optimizations passes are taking Gimple as input and producing Gimple as output; later emitting assembler or machine code from it) to object code.
BTW, with recent GCC (notably libgccjit) and LLVM infrastructure, you could use them to compile some other (or your own) language into their internal Gimple or LLVM representations, then profit from the many optimization abilities of the middle-end & back-end parts of these compilers.

Compilation to bytecode vs machine code