Is there a way of keyframing RGB curves?

Question: In the node editor the RGB Curves node only lets me keyframe the factor. The control points have boxes for x and y coordinates, but it doesn't allow me to keyframe these boxes. Is there a way around this?
Answer: All of the node data is available through python so a workaround could be to use a python script to adjust the curve at the right time.
To view the curve data you can use a script like -
import bpy

theCurveNode = bpy.data.materials['Material'].node_tree.nodes['RGB Curves']

print("R Curve points are:")
for point in theCurveNode.mapping.curves[0].points:
    print(point.location)

print("G Curve points are:")
for point in theCurveNode.mapping.curves[1].points:
    print(point.location)

print("B Curve points are:")
for point in theCurveNode.mapping.curves[2].points:
    print(point.location)

print("C Curve points are:")
for point in theCurveNode.mapping.curves[3].points:
    print(point.location)

So curves[] will always be 0-3 for RGBC and each curve can have any number of points. It would be tedious but you could use the script to generate a list of values that you then use as data for the script that imitates keyframes. Possibly calculating them or interpolating smoothly between frames.
theCurveNode.mapping.curves[1].points[2].location.x = myCurvePointLocX(1,2)
theCurveNode.mapping.curves[1].points[2].location.y = myCurvePointLocY(1,2)
theCurveNode.mapping.update()

Be sure to run mapping.update() after altering any curve points.
You could then setup a script that appends a function for bpy.app.handlers.frame_change_pre that alters the curves based on frame_current.
I can't say this is a recommended method but in theory it could work.
Answer: It's apparently not possible; as a workaround, you could use a different node that you can keyframe, or use two or more rgb curve nodes and animate a mix node between them:
add two or more rgb curve nodes using the same input and configure them as you like(for example each node reprents a key frame - start rgb values,intermediate rgb values, and end rgb values; mix their outputs in proper order using color mix nodes, and then animate the mix nodes factor. hope that's clear, sorry for the colossal delay, I've been signed in on a different account :)
Comment: Could you explain how to do this?
Answer: Good idea to use a RGB mix node as a workaround to keyframing RGB curve values. I wanted to make a sky get darker by keyframing the RGB curves, but ended up duplicating the sky (one light, one dark), and then transitioned from light to dark by keyframing the mix node. Worked great.


Mask only 9 digit number

Question: I want to mask only 9 digit number in string. If string contains less than 9 or greater than 9 it shouldn't mask that number.
My code:

var str = 'My Business phone number is 1234567890 and my personal number is 123456789';

var rgx1 = /\d{9}/;

var find1 = rgx1.test(str);

if(find1){
     var str1 = str.replace(/\d{5}/, '#####');
     console.log(str1);
}

Result: My Business phone number is 1234567890 and my personal number is #####6789
But this code returns true if it has more than 9 digit number and also if string contains 9 and 10 digit number it should mask only that particulr 9 digit number.
Answer: You can do this in one regex, to capture 9 digit numbers, surrounded by word breaks:

const test = "nine digits: 123456789 and ten digits 0123456789"
console.log(test.replace(/\b\d{5}(\d{4})\b/, '#####$1'))

The regex looks for: a word break, followed by 5 digits, followed by 4 digits, followed by a word break. The last four digits are captured so they can be referenced by $1 in the replace
This is a preferred solution because you don't have to worry about any edge cases such that you have part of your string match your outer regex, but a different part of the string match your inner regex.
Comment: you have only 4 symbols #. One # is missed.
Answer: In your code, the test part matches if the string contains 9 consecutive digits which also matches if there are 10 digits. Then you replace 5 digits of the the first occurrence (which is 1234567890) with #####
What you might do is omit the var find1 = rgx1.test(str); part and use  \b\d{9}\b which uses a word boundary \b to make sure it is not part of a longer match.
You could use replace with a callback function. In the callback function replace the first 5 digits with #####. To replace all matches instead of only the first you could add the /g modifier.

var str = 'My Business phone number is 1234567890 and my personal number is 123456789';
var str1 = str.replace(/\b\d{9}\b/g, function(match) {
  return match.replace(/\d{5}/, '#####');
});
console.log(str1);

Mask only 9 digit number


Xerox Phaser 6022 won't wake up from sleep

Question: I recently purchased 3 Xerox Phaser 6022 units.  Two of the three were connected via USB and the third was connected to the wireless network for printing.  I was using the latest available firmware (01.07.00.30.3938).  The two that were setup for USB printing would go to sleep after the default setting of 5 minutes and couldn't be woken up via the PC or pressing any of the buttons on the unit.  You'd need to hit the power switch and wait for the printer to reboot.  This would happen when the unit was disconnected from USB confirming my belief that it wasn't PC related.
Answer: Update to the lastest firmware from xerox's website
http://www.support.xerox.com/support/phaser-6022/downloads/enus.html?operatingSystem=win7x64
it fixes the sleep issue.
Answer: The solution: Disable wifi if the printer isn't using it to print.
Disabling Wireless Networking from the Control Panel on the unit.
You can disable the wireless network from the printer control panel.
To disable wireless networking from the Control Panel:
1. At the printer control panel, press the System button.
2. To navigate to the Admin menu, use the Up and Down arrows, then press OK.
3. Navigate to Network, then press OK.
4. Navigate to Wi-Fi, then press OK.
5. Select Off, then press OK. It will say that the printer needs to restart for the change.  I think I just pressed the power button.
When it comes back up you'll know if the change worked by the fact that the WiFi button will be off and you'll be able to wake the printer up by sending a print job to it after it's gone to sleep.  I've passed my findings on to Xerox and hopefully they'll address it via a firmware update but I hope this can help someone else.


When Should an Auto Logout Popup Warning Message Appear?

Question: My application is required by our security team to log users out after 20 minutes of inactivity.  We don't currently have a message warning users that this will happen, leading to confusion/frustration for users.  Is there an industry for how soon a message should appear?  The last 10% of the timer?  I.E. 2 minutes in my scenario.
Comment: Does this answer your question? [How should I correctly implement a timeout warning?](https://ux.stackexchange.com/questions/30426/how-should-i-correctly-implement-a-timeout-warning)
Comment: Maybe also [this question](https://ux.stackexchange.com/questions/30426/how-should-i-correctly-implement-a-timeout-warning) helps you
Comment: That question doesn't address when the timeout warning should appear, which is what this question's about.
Answer: There is no industry standard, but there are plenty of patterns, best practices you can use.
I think, you should do a so-called best practice research and examine similar applications, services. Typically, the banking sector and eGov sites are using timed login solutions for security purpose. For example, the most common element of these is a time counter. And usually, there are no popup before it logs you out. If the user reaches the inactivity threshold, it assumes that the user is no longer at the computer and logs it out without any warning to prevent any security issue. If the user is not there, no popup message or dialog will help or work. This is why they are using a counter instead. There are several solutions. Some of them resets the count-down after each interaction and have a few second delay.
For example, it starts to count down the timer after 20-30 seconds of inactivity (this is the delay) and resets the counter right after the first interaction.
The count-down shows 10 minutes > the user did something on the webpage, filled some forms, etc. > then moved to another tab of the browser or had to go out for his/her wallet because the form is asking for ID or credit card number > the count-down starts after 30 seconds of inactivity > the user gets back after 3 minutes, the count-down is currently showing 7 minutes 10 second > the user stars to type the credit card number into the input field > the count-down resets back to 10 minutes.
Answer: I don't know if an industry standard exists, but the project I'm working on pops a warning one minute before timeout and that's worked for our users for years.
Comment: I think I've seen the 1 minute timeframe used in some mobile banking apps.
Answer: I don't think there should be any warnings or popups. For example, if there's actually an intruder who gets their hand on the computer / mobile phone with your application logged in, and a popup appears with the reminder, it will be even worse for security. The whole point of session time out is logging the user out if they are away and unintentionally forgot to log out of the application.


Moving OneNote in sharepoint using files explorer breaks Get pages

Question: We moved OneNote hosted in SharePoint from one folder to other using file explorer (View in file explorer option). After the OneNote is moved it started looking like a folder instead of OneNote file and we don't get the notebook which we moved in Get Note books API call. Accessing the one note from client works normally. It is just that OneNote which is moved is not listed in Get Notebooks API call. How to fix it?
Answer: I work on OS X so I hope this answer is relevant to your situation.
Uploading a notebook to SharePoint results in it losing "special permissions" and becoming just a regular folder (I think this is what is happening to you too).
The workaround I use is to create a new OneNote notebook with the same name and then copy the files from the old notebook to the new one and it will work again in the API.
The actual pageIDs will change as the new notebook has a different ID and you will have to reload the notebook in the OneNote app.
It would be great if there was a function in the API to download and upload Notebooks to Sharepoint, I put a suggestion into the OneNote API's user voice.


i have cut my cement board too short for my shower walls

Question: I have cut my cement board too short for my shower walls; I need another 2 inches so it lines up right. Should I cut a 2 inch piece of cement board or go ahead and tie in the drywall for the remaining 2 inches?
Comment: Photos or a sketch, please.
Comment: Hello, and welcome to Home Improvement. What do you mean by "tie in the sheetrock"?
Answer: I'm going to speculate that you've set your cement board tight to the floor, and that it reaches two inches short of the height you'd like your tile to reach. I'm also going to guess that you haven't installed the drywall above the cement board.
Yes, you can bring your drywall down to the height of the cement board and lap the tile onto it. In fact, this is a more ideal scenario since it leaves you with a clean surface on which to terminate the tile. You'll probably want to finish the drywall and paint before setting the tile so that the grout or trim can lap over the paint for the cleanest lines.


Faces are getting thinner as i extend them.. How do i fix this?

Question:
(I'm new to blender :) It keeps getting thinner like this when I extend the faces with >E. deleting them leaves a big face-hole at the main body. don't know how to fill it up. I just want this tail to look fatter and less ''poly-ish''(?) If its easier to fix this for me you can download the .blend here https://we.tl/t-UWNdpDSHS8. I just need help.
Answer: If you want to prevent the tail from "thinning" as you "pull it out" you can press "shift + y" to exclude the y-axis from the transformation.
If you want to fill in missing faces select all points around it and press "f".


What diseases could be transmitted skin to skin (massage)?

Question: What kind of diseases one can get from a skin-to-skin interaction such as getting full body massages (without touching intimate parts) assuming a person had mild skin damages that occur after shaving or pimple removal?
Answer: See this February 1 2022 Webpage by Matt Alderton, from the American Massage Therapy Association.

"Massage should be avoided when the client has a communicable disease," cautions Grabell, who says contraindications are for the good of both the client and the practitioner. "For example, clients with athlete's foot can have the fungus spread to other areas of the body, as well as to the therapist. Other examples include viral illnesses caused by the herpes virus—chicken pox, shingles or cold sores—or bacterial infections … However, if the client has a skin condition that is not communicable, then massage can proceed."

See Health Precautions for Massage Therapists by Ruth Werner, "Board Certified in Therapeutic Massage and Bodywork (BCTMB)".

2. Bacteria Are Shared Easily
Bacteria are stronger now than they were even a few years ago, and species like methicillin-resistant staphylococcus aureus (MRSA) can cause long-term problems. Other easily shared bacteria can cause impetigo, pinkeye, and – if the immune system is weak – infection of the lymph or blood. Ask yourself:

Does your client have an undiagnosed, untreated skin infection? If yes, refer your client to their doctor and reschedule.
Do you or your client have open, uncovered lesions (think hangnails, scabbed over bug bites and the like)? If you find one, cover it and/or avoid direct contact.


correlation between imputed genotype and true genotype

Question: There is a graph in the link https://odelaneau.github.io/GLIMPSE/rsquare_eur.html. This graph shows the imputation accuracy of certain MAF bins. Now I understand that $r^2$ is the correlation between imputed genotype and true genotype. What I don't understand is how they calculate this $r^2$ correlation. Can anyone suggest to me how I can define the r^2 correlation between true genotype and imputed genotype? I suppose it depends on the individual who defines his own $r^2$. So, it may differ for the different algorithms. However, different aspects or different $r^2$ definitions will help me understand and represent this graph slightly differently.
Answer: This is done by downsampling. Take the 1000 genomes, set some genotypes as missing <code>./.</code>, impute them using GLIMPSE, then measure correlation between the genotype dosages in the imputed dataset and the same sample at high coverage - in this case, the 1000 genomes sequenced to 30x coverage by the NY Genome Centre.
Comment: Is the correlation a Pearson correlation coefficient?
Comment: @winni2k judging by this yes I think so https://github.com/odelaneau/GLIMPSE/blob/master/concordance/src/utils/basic_stats.h#L110


Energy per unit time of spontaneous emission within second quantisation problem

Question: I'm studying second quantisation and I have the following problem concerning the spontaneous emission that corresponds to the decay of an atom from the level $
\lvert2\rangle$ to $
\lvert1\rangle$ and I want to show within the dipole approximation that the energy radiated by the atom per unit time can be written in the form
$\frac{E}{t}=\frac{4e^2}{3c^3}\langle1\rvert \frac{d^2\hat{r}}{dt^2}\lvert2\rangle$. Long story short, using the lifetime of the excited state equation I arrived to $\frac{E}{t}=\frac{4e^2}{3c^3}\langle1\rvert \hat{r}\lvert2\rangle$. The solutions suggest that $\langle f\rvert \hat{r}\lvert i\rangle=-\frac{1}{\omega_{fi}^2}\langle f\rvert \frac{d^2\hat{r}}{dt^2}\lvert i\rangle$, where $\omega_{fi}=\frac{E_1-E_2}{\hbar}$ but I fail to see how to get to this last equality. Any hint of how you get it?
Thank you.
Comment: In the Heisenberg picture, the time derivative of an operator is related to the commutator of the Hamiltonian with that operator. This leads to the last equality.
Answer: In the Heisenberg representation, we have that $\mathcal{O}(t)=e^{iHt} \mathcal{O}(0)e^{-iHt}$. For the position operator, $r(t)=e^{iHt} \mathcal{O}(0)e^{-iHt}$, so sandwiching between two energy eigenstates we obtain
\begin{align}
\langle 1|\hat{r}(t)|2\rangle=\langle 1|e^{iHt} \hat{r} e^{-iHt}|2\rangle=\langle 1|e^{iE_1t} \hat{r}e^{-iE_2t}|2\rangle=\langle 1|\hat{r}|2\rangle e^{i\left(E_1-E_2 \right)t}
\end{align}
Differentiating both sides with respect to time twice, and inserting the factors of $\hbar$ where appropriate, proves what you're after.


Creating objects without breaking encapsulation

Question: I'm fairly new to all this, so this is probably OOP 101 but I can't get my head around it, assume the following C# code lives in an assembly:
internal interface IDataStore
{
    void Store(string name, object data);
    object Retrieve(string name);
}

internal class DBStore : IDataStore
{
    public DBStore(string connection) { }
    public void Store(string name, object data) { }
    public object Retrieve(string name) { }
}

public class GizmoManager
{
    public GizmoManager(IDataStore dataStore) { }
    // Other stuff
}

public class WidgetManager
{
    public WidgetManager(IDataStore dataStore) { }
    // Other stuff
}

If a second assembly tries to create a GizmoManager and a WidgetManager, it can't because it has no way to get hold of a DBStore (since it is internal not public).
The following don't work AFAICS:

Make DBStore and IDataStore public. Bad because the client assembly can then bypass GizmoManager/WidgetManager and access the DB however it likes.
Don't pass in an IDataStore to the GizmoManager and WidgetManager constructors. Bad because it reduces testability (you can't easily pass in a MockDataStore).
Do something magic with factories. Doesn't seem to solve anything because you need to pass the same IDataStore to both GizmoManager and WidgetManager and thus the client assembly still needs to assign an IDataStore to a variable (which it can't because IDataStore is internal).

This is probably stunningly obvious but I just can't see it. How would one overcome this contradiction?
TIA.
Answer: Just make the interface IDataStore public. That way, clients can instantiate your WidgetManager and GizmoManager classes with mock objects they create themselves.
Implement on of the Factory class of design patterns to allow creation of GiszmoManager and WidgetManager objects by client code. That way, client code can never create a DBStore object, so they can never circumvent your managers.
BTW: Why bother fussing with encapsulation? This might make sense if you are in the proprietary frameworks business, but otherwise, YAGNI.
Answer: Make IDataStore and DBStore public but make the DBStore constructor internal.  Then assemebly 1 has complete control over when DBStores gets instantiated, but assembly 2 is able to access and pass in the DBStore.
I imagine you will then want a factory in assembly 1 that limits the number or configuration of the DBStore instances that get created.
Answer: You can make the interface and classes public, but make the methods to access the database directly internal. This way, you instantiate an instance of your DBStore, without allowing any access on methods that other assemblies are not allowed to.
internal methods are only visible to classes in the same assembly.
I would rather check if there is no way to assemble your objects without the need of instantiating a DBStore every time. Perhaps a factory pattern or dependency injection? Then you can make your interface public, and let a factory inside the first assembly instantiate them. This does not impact testability, but does reduce the object instances you create. Less new XYZ() statements is better...
Answer: Make DBStore public, butmake all members that you don't want to expose private or internal.  Then...
Option 1: Remove all members from IDataStore that you don't want to be accessible outside of the assembly, and make IDataStore public.
Option 2: Rename IDataStore to IDataStoreInternal, and make it inherit from a new public IDataStore interface that has no members (or only members that you want to expose externally).
Answer: I like both of these:

Don't pass in an IDataStore to the GizmoManager and WidgetManager
  constructors. Bad because it reduces
  testability (you can't easily pass in
  a MockDataStore).
Do something magic with factories. Doesn't seem to solve anything because
  you need to pass the same IDataStore
  to both GizmoManager and WidgetManager
  and thus the client assembly still
  needs to assign an IDataStore to a
  variable (which it can't because
  IDataStore is internal).

To solve testability but hide implementation, the public interface should only offer the option of whether the stores should be live, testable, pre-prod etc. So you could delegate responsibility for correct IDataStore construction to another party that is inside the assembly. E.g. a factory concept that only allows you to set "testing", "deploy", "debug", etc. Have default constructors (or singletons or whatever) that refer internally to the factory for the correct storage given the "mode" setting.


Mass-energy equivalence and gravitational potential energy

Question: If mass and energy are equivalent, and if gravitational potential energy is energy, why doesn't an object have more mass when it is at a higher altitude? Does the mass-energy equivalence work for kinetic energy only?
Comment: Mass has an associated energy. Not all energy actually  has mass. However it is always possible to say "this is the same thing as IF it has x amount of added mass"
Answer: An object doesn't increase mass when its energy increases. The rest mass is the rest mass. Even with kinetic energy. If an object is moving, its mass doesn't increase. You can associate a mass to the system, however. So let's say two particles are vibrating in a molecule, each with mass $m_0$, then the molecule's mass wouldn't just be $2m_0$, you have to take into consideration that the particles have energy. The same is with gravitational potential energy. The object's mass doesn't increase when it goes up similar to how it doesn't increase when it moves faster.
That said, let's find out how such mass would work. Similar to how we assumed the molecule isn't moving, but its particles are. Let's assume a large box with the vertical length 1km. If there is an object at the top of the box, it has higher potential energy, so you could say the box has more mass than if the object was on the bottom of the box.
Answer: In the view of general relativity, gravity in reality does not have any form of well-defined potential that can be considered "energy" in the same sense as the components of the stress-energy tensor $T^{\mu \nu}$. The notion of energy as we define it is simply the volume integral of one of the elements of this tensor:
\begin{equation}
E = \int T^{00} \, d\mathcal{V}
\end{equation}
The effects of gravitation are simply geometry, or more aptly put, the geometric deformation of the spacetime metric $g_{\mu \nu}$. The constituents of your theory when describing a certain system (in the Lagrangian formalism) are explicitly sundered into gravitational ones and matter ones:
\begin{equation}
\mathcal{L} = \mathcal{L}_{G} + \mathcal{L}_{m}
\end{equation}
Any notion of energy in the classical sense that can be expressed in the stress-energy tensor is strictly part of the matter part of the Lagrangian $\mathcal{L}_{m}$.
The gravitational potential in the Newtonian picture can be seen as a small perturbation of a flat Minkowski metric (in units where $c=1$):
\begin{equation}
g_{\mu \nu} =
\begin{pmatrix}
-1 - 2\Phi & 0 & 0 & 0 \\
0 & 1 & 0 & 0 \\
0 & 0 & 1 & 0 \\
0 & 0 & 0 & 1 \\
\end{pmatrix}
\end{equation}
where $\Phi \ll 1$ the gravitational potential that gives the Newtonian law of gravity:
\begin{equation}
\nabla ^{2} \Phi = 4\pi G \rho
\end{equation}
with $\rho$ being the energy density of what causes this tiny perturbation of the metric, and which is precisely the $T^{00}$ component of the stress-energy tensor:
\begin{equation}
E = \int \rho \, d\mathcal{V} \approx M
\end{equation}
where the approximation occurs when we consider that the object is non-relativistic in the kinematic sense ($v \ll c$) which means its energy density is roughly equal to its matter density.
To put it more succinctly, in general relativity energy is anything that bends the spacetime, while gravity is the observable effect of that bending i.e. how it impacts the dynamics of those objects who act as sources of energy.
Answer: Well, I would say object has less mass when at lower altitude.
As an example, it's easier to accelerate two boulders when they are close to each other. I mean accelerate to the same direction.
If those boulders are accelerated to different directions, then gravito-magnetism (not mass) makes the required forces larger.
See the accepted answer here:
Special relativity and acceleration of an object falling in a direction perpendicular to the direction of motion
Comment: I am afraid you are confusing mass calculated from energy (E/c^2) with mass meant as inertial mass or rest mass. When you shoot horizontally with rail-gun on Mount Everest or at sea the outlet velocity of you bullet will be the same.
Comment: @JanGogolin When you shoot horizontally with rail-gun on Mount Everest or at sea the outlet velocity of you bullet will be the same, although the upper capacitor pack contains more energy.
Comment: "Well, I would say object has less mass when at lower altitude." What is your object in my example, the bullet or the capacitor? Maybe you will find useful my recent answer regarding the notion of inertial mass: https://physics.stackexchange.com/a/714937/281096 .
Comment: @JanGogolin Answer:  Bullet. Let's say we have two coil-guns, far apart. When we move them closer together, some energy is released. We store that energy. I trust that, as you say, the velocity of fired bullets is not affected by this operation. But we can give the bullets some more speed by using the stored energy. But now the bullets have to climb  uphill, so that the final speed is unchanged, as it should be.  So we took mass from bullets, we accelerated low-mass bullets to extra high speeds, then a system of fast low-mass bullets became a system of slow normal-mass bullets.
Comment: I would like to recommend you to read Evan Currie's "Odyssey One Series" (my favorite SF book), especially part "Holy Ground".  They use there some kind of system you are talking about. Regarding your consideration, there is a difference between some system of interacting objects and a single one. As you certainly know the mass of hydrogen nucleus is lower as of proton and neutron disconnected. The energy of missing mass, the so-called mass defect  ($\Delta E=\Delta m c^2$) is what we hope to use for energy generation by fusion.
Answer: When one mass is at some distance from another, we may say there is gravitational potential energy in the system. But where is this energy physically located? It is not inside one mass or the other. Rather, it is located in the gravitational field.
If we adopt the perspective of general relativity, we do not have to speak of a gravitational field, but we can say that spacetime carries this energy. But the physical interpretation of gravitational energy is quite subtle. It is accounted for via the non-linearity of the Einstein field equation.
To help think about this you can notice the following: the total gravitation presented by two close-together masses is less than when they are further apart. To be precise about what I mean by this, consider the case where we have a spherical mass $M_1$ and, around it, a spherical shell of mass $M_2$. Let mass $M_1$ have radius $a$ and let the internal radius of the shell be $b$, with $b$ comfortably larger than $a$. The gravitational effects at some radius $r > b$ can be measured or calculated. Now let $b$ get smaller by allowing the shell to shrink without extracting any matter or energy. It helps to have a precise model in order to track what is happening, so let's suppose that $M_2$ consists of a large number of heavy rocks held apart by rods. To make $b$ get smaller, we let all the rods get shorter, allowing them to be compressed.
In this scenario, as $b$ gets smaller, the gravitational effects at the given $r$ (indicated by things like the period of a circular orbit, the acceleration needed to stay in one place, and the time dilation) do not change. This is associated with a theorem named after Birkhoff. But in this thought-experiment, as $b$ gets smaller there is some elastic potential energy building up in the rods which are keeping $M_2$ from collapsing. So some of the gravitation is owing to this elastic potential energy, rather than to just the rest mass of the rocks of $M_2$. If we now extract that elastic potential energy and carry it away then, after it has been removed, the gravitational effects at $r$ are smaller than they were.
So in this end configuration there is the same amount of matter (i.e. the rocks) but they cause a smaller gravitational effect when those rocks are lower down (i.e. nearer to the central mass $M_1$).
In a similar way, if one now supplies energy so as to lift the rocks up again, then the gravitational effects at some given $r > b$ will get larger. In this way the intuition which motivated the question is largely vindicated, but the whole thing is quite subtle when gravitation is involved. In order to speak about mass and energy in general relativity one has to be quite careful to say how they are defined whenever the system in question is large enough that its own gravitation has to be considered.
A good intuition can also be obtained by using the concept of binding energy. The total inertial mass of any bound object is smaller than the sum of the inertial masses of its constituents taken one at a time, and this remains true whether the object is bound together by electromagnetic or gravitational (or other) forces.


What are the proposed models for the existence of bars in galaxies?

Question: What are the current explanations and models for the formation of a central bar in some galaxies, and what is the difference that can produce a barred galaxy instead of a spiral one ?
Comment: I think it's explained here clear enough: http://en.wikipedia.org/wiki/Barred_spiral_galaxy
Comment: By explained I mean shows how little we actually know about it =)
Answer: It's my impression from skimming the literature just now that much of the current activity in this field is based on N-body simulations.  It's hard for me as an outsider to evaluate the analytical scenarios that are being tested, but I think that the key idea is that certain Lindblad resonances which excite density waves are the main instabilities that lead to bar formation.  See also section (4) of this page, which gives a broad overview of stellar dynamics in galaxies.
In short, there are several guesses out there.  See this paper by Steinmetz for an overview of the understanding of galaxy shapes in general in 2002.
The key citation in the wikipedia article linked to by Cem is a 2002 paper by Bournard and Combes (free on the arxiv) which describes gravitational N-body simulations which follow processes of bar formation and re-formation.  They find a strong dependence on the frequency of bar formation on the distribution of mass in the galaxy:

A galactic disk may either keep a single bar or get several successive bars. By simulating several disks, we study the dependence on physical parameters. We find that the two determining parameters are the bulge to disk and halo to disk masses ratios. Light bulge galaxies maintain their bar, while bars are destructed and regenerated in heavy bulge galaxies. The halo mass has also an effect on the disk evolution.

Another paper from 2002 by Steinmetz and Navarro does a different simulation and observes that a bar is formed in their model galaxy due to the tidal forces from a satellite galaxy.  Here's a related image from their paper:

Caption: Fig. 4.  The tidal triggering of bar instability by a satellite. At z=1.6 the disk develops a well defined, long-lasting bar pattern as a result of tidal forcing by the satellite shown in the z=1.2 panel. The satellite is finally disrupted at z=1.18 after 7 pericentric passages. The bar pattern, however, survives for several Gyr, as shown in the picture. Stars less than 1.5 Gyr old are shown in blue, older stars in red. Note that the bar is most prominent in the young component. Horizontal bars in each panel are 5 (physical) kpc long.
Answer: Another proposed mechanism for the formation of a bar is that the dark matter halo surrounding the galaxy is elongated rather than spherical. This is unlikely to apply to massive galaxies where the stellar disc is massive enough to locally overwhelm the gravitational potential of the halo, but in dwarf galaxies the disc is (almost) a collection of tracer particles in the halo potential. The orbits in the disc end up elongated in the direction of the longest halo axis, resulting in what is basically a bar. It's a bit different from the photogenic bars you see in pictures of giant galaxies - these are much weaker visually and are easier to pick out looking at the velocities of stars/gas in the disc. The bar also rotates much more slowly (low pattern speed); its rotation speed is locked to the rotation of the halo, which is much slower than the orbital period of the galaxy. This model is still a "prediction"; there is at best tentative evidence for the presence of weak, slow bars in dwarf galaxies, but it is not ruled out, either. The details are laid out in this paper (I am a co-author).  Here's part of one of the figures, showing the elongated stellar distribution, i.e. the bar, in a simulation (left), the corresponding elongation in the dark matter halo (centre) and the elongation of the gravitational potential (right).


What are the authoritative books advocating restrictions on Freedom of Speech?

Question: I have read the authoritative books in favor of freedom of speech (and in favor of freedom in the larger sense), but for the sake of learning, I wanted to know what were the authoritative books and arguments against unlimited freedom of speech. I can't seem to find a list for that.
Comment: What are "the authoritative books on freedom of speech"? What makes a book on that topic authoritative?
Comment: Maybe useful: [Freedom of Speech](https://plato.stanford.edu/entries/freedom-speech/) with biblio.
Comment: At least in the US, "freedom of speech" has highly positive connotations, to the point that basically no one labels themselves "against free speech."  This would be like labeling oneself as "pro-Nazi" or "defending racism"; these kinds of labels are used only by one's opponents.  I recommend rephrasing your question:  "I have read books by X, Y, and Z on freedom of speech.  What books should I read for contrasting or opposing views?"
Comment: I think there is a SEP on Freedom of speech. Also you might want to read about this fellow Juan Donoso Cortes. http://www.iep.utm.edu/donoso/  I found this by doing a search for "de Maistre freedom of speech philosophy". None of this is my cup of tea, nevertheless you ask so I pass this along for what it's worth.
Comment: Over the centuries supporters of authoritarian regimes have given their leaders loads of reasons in favor of the prior restraint of speech. Is there any particular situation you are thinking about?
Comment: Usually the arguments against unlimited freedom of speech use the phrase "hate speech" to describe speech acts they think should be censored. Rae Langton (inter alia) offers such an argument.
Comment: Censorship is a sign of weakness; it tells the world that the censored has touched a serious nerve.
Comment: @GeorgeChen The people who support "free speech" are weak too. They get their knickers in a twist when we don't agree with their opinions on "human rights" or "freedom"
Answer:
...the authoritative books against [freedom of speech]

Two passages from Orwell's Nineteen Eighty-Four : (1) O'Brien's conversation with Winston Smith while interrogating Smith in prison; (2) The Book, which explains the social system of Oceania, and which Smith reads after joining The Brotherhood.
Answer: Perhaps you need to clarify what you intend 'freedom of speech' to cover and include. Below I take it that you are concerned with freedom of speech in the sense of the expression of ideas, principles, beliefs. One might call this a political construction of 'free speech'. However, do the many socially imposed constraints on certain words and expressions that are widely deemed to be unseemly also fall within the scope of freedom of speech ? There are many words, not at all expressive of ideas, principles or beliefs, which are unusable because they violate social mores. There are also questions I cannot ask people (not that I'm inclined to) because they involve a violation of privacy. Involved here is no less a constraint on freedom of speech than my being forbidden to express (say) racist views.
That's just a clarificatory point. Down now to what I think is your immediate interest.
Sir James Fitzjames Stephen's 'Liberty, Equality, Fraternity' (1874) is a wholescale attack on John Stuart Mill's 'On Liberty' (1859). Mill defends freedom of speech; Stephen takes an opposing view.
Among more recent texts see 'Speech and Harm: Controversies Over Free Speech' (Oxford, 2010). For a feminist perspective see Eric Hoffman, 'Feminism, Pornography, and Law', University of Pennsylvania Law Review, Vol. 133, No. 2 (Jan., 1985), pp. 497-534. James Weinstein, 'Hate Speech, Pornography, And Radical Attacks On Free Speech Doctrine' (1999) is worth reading.
On pornography (which may not be your particular concern) Philip Jenkins, 'Beyond Tolerance: Child Pornography on the Internet' (2003) is useful.
Answer: I would think that this argument will be very ill received because it criticizes revisit principles of religion.
In the big Abrahamic religions a set of rules have been written down, in some cases to prevent the spread of diseases, the prohibition against pork in Judaism and Islam, in other cases to control a population, the burka or niqab i Islam.
Eventhough Jesus sought to get rid of these rules the church later created Hell and imposed decency and good manners.
In all religions springing from Abraham a certain criticism of the free speech have later been developed. An example of this is the Muhammed drawing by Kurt Westergaard. Here islamic leading figures required an apology from the state of Denmark, the newspaper who printed them and the cartoonist himself, by referring to scriptures not allowing it, written in religious books.
There are many examples in Israel where freedom of speech have been under attack by the Orthodox jews.
A religious censorship has resurrected. Since religious books in many countries have strong ties with state policy, Iran and in some cases the US, I would see parts of the bible, the quran and other religious texts as being Authoritative.


How to safely copy home folder from a 10.04 desktop to a new ubuntu 12.04 installation on a notebook?

Question: Recently I've bought a new notebook.
I'm going to install ubuntu 12.04 next to win8 with dual boot config.
Is it that simple and safe to just copy my home folder from an old desktop with Ubuntu 10.04 to a new 12.04 installed system? Or should I do that other way?
Answer: Yes, just copy over your home directory. These are the steps I would follow:

Make a proper archive on the old system.
cd /home
sudo tar -zcf username-archive.tar.gz username

Make sure that you use the same username on the new system.
Copy over the archive to the new system outside the home directory where we will unpack it to of course.
(Re)boot up the new system, but don't log in yet. This will make sure nothing will be running under your user account, depending on the contents of your homedir.
Press Ctrl+Alt+F1 to go to a virtual terminal.
Log in, then become root fully, e.g.
sudo su -

Backup the almost empty homedir, e.g.
mv /home/username /home/username-old

Unpack it, e.g.
cd /home
tar -zxf username-archive.tar.gz

Answer: No, it is not recommended to copy the home folder since it contains hidden files that have settings for programs that may not merge perfectly with the new installation versions of programs that might operate a bit differently to their older versions.
But you can copy each folder in the home folder (Documents, Downloads, etc.) to the new machine after Ubuntu is installed.
Comment: Why would this be unsafe? Then all dist-upgrades would be unsafe too... as your full /home is kept then with new versions as well. I think this answer is simply untrue.
Comment: @gertvdijk, made some improvements. I can remember that I had some problems with compiz and unity (or something related to them) settings merging in the past which might happen here.
Answer: You must copy your Home folder content in a Home Folder in new notebook by open nautilus in terminal :sudo nautilus
and Use a removable drive or Connect to Harddisk together.
Then You must change User owner of files to user in your new notebook by:
cd ~
sudo chown -R YourUsername *

you can copy most application setting that is in your old home folder and they are hide with began their name by '.'.
Don't copy all of hidden folder in home like .config . it may crash your os because their version isn't same. just copy all you need.
Comment: Why would the system crash because of the older configuration files in the `/home` dot-directories are still present? That would mean that all Ubuntu upgrades would result in crashes as they upgrade full Ubuntu versions without touching the homedir contents. This answer is simply untrue.
Comment: I have kubuntu 13.10 . when i update to 13.10 by keep home folder my kubunt crashed. And then I had to remove all configuration files in live cd  to solve that.


Desktop shortcuts for quick access to streaming specific shows on specific services

Question: Short version:
I would like to create a way to double-click Windows desktop shortcuts which open up a browser window and immediately start streaming a particular show on a particular service (Disney, Prime Video) without needing to interact with the menus of those services.
Long version:
I am working from home a lot lately. Thus I need to sometimes give my kids TV time so I can be left alone. I have an Amazon Fire TV. Between its inherent slowness and 30-clicks-to-navigate-through-the-menus, it often takes time I don't have to get the kids favorite shows on. However, I have a spare PC (Windows) that I've hooked into the TV to bypass the TV's menus which has been great.
Now I'd like to take it a step further and bypass the menus of the streaming services (Disney+, Prime Video, etc) so that we can go straight to the show they want to watch. My idea was to use Windows desktop shortcuts. This is where I need help.
Is there a way to create a URL with these streaming companies that allow you to accomplish what you want without interacting with their menus? For example, I want a desktop shortcut that does the following:

Open Firefox -> Open Disney Plus -> Open Bluey -> continue previously being watched episode. If necessary, start at episode 1.

I'd also create shortcuts for Mickey Mouse, Daniel Tiger, Frozen, Moana, etc.
So far I've only found out how to link to a specific video but I would like it to be a little smarter and link to a show and continue where it left off, rather than replaying the same video every time they click the shortcut.
Any other general ideas are welcome. Using Windows, how would you accomplish a way for your kids to queue their shows with low-interaction?
Answer: One idea that might work is creating a batch file that opens Firefox with an argument for the url: start firefox <website>. You could then add the file to your Desktop directory for easy access of it.
REM opens Firefox with the url argument
start firefox https://www.example.com
echo opened Firefox


Change the null placeholder in a Cocoa binding?

Question: Is there a way to change (for the purpose of localization) the null placeholder in a binding in Cocoa?
The bindings are set up in Interface Builder for a popup button. The two-way nature of the bindings as set up in IB is needed, so doing it programmatically is not really appealing.
I am aware that the standard way of handling localizations of a nib file is by making one for each language, but since this is the only difference in the whole nib file between the language versions, it seems a bit excessive for a single string.
If there is a way to modify a binding created in IB, I was thinking about doing it in the file's owner's awakeFromNib method.
Answer: In the controller object to which you bind, such as your NSDocument class, override -bind:toObject:withKeyPath:options:. This needs to be the target of that method invocation – the object you select under Bind to: in the nib.
If you bind to an NSObjectController or NSArrayController, you'll need a subclass.
That method should rewrite the options dictionary and invoke super, replacing the value for NSNullPlaceholderBindingOption with your localized string.
I would omit the null placeholder from the nib and that key value in code, though you could of course take the passed-in value for that key and translate it, instead.
Comment: This did not seem to work for me. I subclassed my `NSObjectController`, and the method was not called.
Comment: Works like a charm, thanks! For anyone interested, I had been mucking around with a value transformer for the selected value, and it works nicely, except it is added as the last option of the menu, while the null placeholder is set at the top of the menu.
Comment: Null values result in different editable/enabled behavior, too, so with a value transformer you'd need to maintain Editable and Enabled bindings too. I thought of offering both options, but this way seemed much easier.
Comment: The only way a view can create a binding to an object is by calling that method, so something is going wrong. Can you post a new question?
Answer: The other answer no longer seems to work so I've come up with a slightly different solution which modifies an existing binding to use the given null placeholder string:
I have this method in my view controller:
- (void)rebind:(NSString *)binding of:(id)object withNullPlaceholder:(NSString *)nullPlaceholder {
    // Possibly a bad idea, but Xcode doesn't localize the null placeholder so we have do it manually.
    NSDictionary *bindingInfo = [object infoForBinding:binding];

    id bindObject = bindingInfo[NSObservedObjectKey];
    NSString *keyPath = bindingInfo[NSObservedKeyPathKey];
    NSMutableDictionary *options = [bindingInfo[NSOptionsKey] mutableCopy];
    options[NSNullPlaceholderBindingOption] = nullPlaceholder;

    [object unbind:binding];
    [object bind:binding toObject:bindObject withKeyPath:keyPath options:options];
}

I call this in awakeFromNib for all the bindings that need it and pass in a localized string:
- (void)awakeFromNib {
    // Hacky hack hack: Xcode is stupid and doesn't localize the null placeholders so we have to do it.
    [self rebind:@"contentValues" of:self.fooPopup withNullPlaceholder:NSLocalizedString(@"No foos available", @"foo popup null placeholder")];
    [self rebind:@"contentValues" of:self.barPopup withNullPlaceholder:NSLocalizedString(@"No bars available", @"bar popup null placeholder")];
}

The localized strings are then localized normally as part of the Localizable.strings file.
Answer: I was able to change the null placeholder string (i.e. "No Value") in a NSPopUpButton that uses bindings.
Specifically, I wanted to have an popup button menu item that had a title other than "No Value" with a represented object of nil. An empty NSString or nil should be saved in the user defaults when the null placeholder menu item is selected.
NSPopUpButton Bindings:

Content is bound to an NSArrayController.arrangedObjects
Content Objects is bound  NSArrayController.arrangedObjects.exampleContentObject (NSString), this is the object that the menu item represents and is the Selected Object,
Content Values is bound to NSArrayController.arrangedObjects.exampleContentValue (NSString), this is the title shown in the popup button's menu item.
Selected Object of the popup button is bound to NSSharedUserDefaultsController.values.ExampleUserDefaultsKey which is the same object type as the Content Objects and Selected Object (NSString). This object should match the object type of the NSUserDefault's key specified in the binding. When an item from the popup button is selected, it will save the Selected Object to the user defaults.

To change the null placeholder string from "No Value" to something else, subclass NSPopUpButton and override -[NSPopUpButton bind:toObject:withKeyPath:options:].

@interface CustomPopUpButton : NSPopUpButton
@end

@implementation CustomPopUpButton
- (void)bind:(NSString *)binding toObject:(id)observable withKeyPath:(NSString *)keyPath options:(NSDictionary<NSString *,id> *)options {
    NSMutableDictionary *mutableOptions = options ? [options mutableCopy] : [NSMutableDictionary dictionaryWithCapacity:1];
    mutableOptions[NSInsertsNullPlaceholderBindingOption] = @YES;
    mutableOptions[NSNullPlaceholderBindingOption] = @"Custom Null Placeholder Text";
    [super bind:binding toObject:observable withKeyPath:keyPath options:[mutableOptions copy]];
}
@end

Finally, select the NSPopUpButton in Interface Builder and under Custom Class in the Xcode Identity Inspector to your the class to the  NSPopUpButton subclass.


Can minors with dual US/UK citizenship travel to the US on their UK passports?

Question: My children have dual citizenship. We live in the UK; their US passports have expired. We are travelling to the States for a week in October. I am hoping that they can travel on their UK passports with an ESTA without problems. Would that work? I have a UK passport.
Answer: All US citizens, even dual nationals, must enter and depart the United States on U.S. passports. Source
My advice would be to reapply for your childrens US passports asap. Source
Comment: @Nicola Just to add to this, US embassy in London has some provisions for expedited passport renewal (for extra payment, naturally) whereby you can get a new passport within 3 days.
Comment: David, have you ever tried this?  Things may have changed very recently BUT i've never known someone to have any trouble with this.  BUT of course you are correct that dat's the law -- as quoted in the first answer here .. http://travel.stackexchange.com/questions/30280
Comment: @JoeBlow No. I am not dual national. The first link has a line further down in the second paragraph last sentence. I am sure there are other sources that will back this up too.
Comment: An expired US passport is prima facie proof of nationality. If the airline will accept it for carriage you will win an interview with an ICE agent. He will tell you that your passport has expired and that you need to get a new one. That is the likely outcome. It's true that you could be sent to secondary examination, and there they will ask why you didn't renew your passport. The fact is, a passport is just one of the ways you can prove your US citizenship. If you are a US citizen you have an absolute right to re-enter the United States as a constitutional matter. This cannot be denied.
Comment: Of course, the airline is a private company and they may or may not accept you for carriage. But once you appear for an INS examination the calculus changes. Cases do not get referred to immigration judges due to expired US passports. The US does not refuse entry or deport those holding expired US passports. Remember that the rules are different for US residents: you do not get the protections afforded US citizens.


How do I remove the legend from a Google geoChart?

Question: How do I remove the legend that appears in the bottom of the Google geoChart? I know that if I don't pass data.setValue to the chart object it wont show, but I need them to populate the map. All I want to do is get rid of the colors. Any ideas?
Comment: "How do I remove the legend" yes the legend that shows in the bottom left of the google svg world map chart
Answer: See : http://code.google.com/apis/chart/interactive/docs/gallery/geochart.html#Configuration_Options

"An object with members to configure various aspects of the legend, or 'none', if no legend should appear."

So basically, when you're passing your configuration options into the API, you want to include the following:
legend: 'none'
A simple example set of chart options would be:
var options = {
    displayMode: 'markers',
    colorAxis: {colors: ['green', 'blue']},
    legend: 'none',
}

The modified version of the marker example provided by google on: http://code.google.com/apis/chart/interactive/docs/gallery/geochart.html#Examples
Comment: Hey IntreipdBrit, thanks for the comment. Do you know if this was just added or has it always been there?
Comment: I have no idea, only recently started using Google Charts.
Comment: It doesn't work for me...this: http://stackoverflow.com/questions/5202029/hiding-the-legend-in-google-chart works instead
Answer: Set the option legend to none.
legend: 'none'

This hides the legend/colorAxis displayed at the left bottom corner of the chart.
Answer: So apparently there isn't a way to do this. If you are using google geoMap wich renders a Flash object then there is a simple property you set to false in the geoMap object to not render the legend on the bottom left. I did how ever using jQuery manage to remove it but that just doesn't flow nicely given that it has to exist in the DOM before you can remove it. If you are seeking to use a world map I strongly recommend jVecotor Map.
It renders exactly the same in old IE browsers and has less vectors in the map so it is faster to load since the DOM is not over saturated.


Who should I call to remove my fireplace?

Question: I'm looking to have my fireplace removed and blocked up in order to use the wall for furniture. I already have 2 vents on the chimney breast upstairs one in each bedroom, I am unsure as to even what forms of trades person carries out this type of work. Any advice and knowledge would be greatly appreciated. Thanks
Comment: A mason or bricklayer would be the person who puts a fireplace in, I imagine they could also take one out. The hearth may be bearing a lot of weight from the chimney, so rather than remove it, it may be more sensible / less expensive to just block it off. If you are handy, there are a few guides online for how to DIY it.
Answer: Any general contractor could remove the fireplace and if the house uses the brick for suport the contractor will be able to do the needed repairs.


Good resources for learning Probabilistic Graphical Models

Question: I recently started taking Probabilistic Graphical Models on coursera, and 2 weeks after starting I am starting to believe I am not that great in Probability and as a result of that I am not even able to follow the first topic (Bayesian Network). That being said I want to make an effort to learn this course, so can you suggest me some other resources for PGM or for Probability which can be helpful in understanding this course.
Comment: This question was crossposted on the Mathematics site.
Comment: Videolectures.net has quite a deep library of recorded talks on graphical models (and computer science more generally), many of them are tutorials. Have a look at http://videolectures.net/site/search/?q=graphical+models
Answer: Prof. Daphne Koller from Stanford has a live online course. One just started a few days ago: https://www.coursera.org/course/pgm .
Her book with Nir Friedman is an excellent comprehensive text book for this subject and an Amazon bestseller (don't worry I don't work for them): http://www.amazon.com/Probabilistic-Graphical-Models-Principles-Computation/dp/0262013193/
Comment: I guess that is exactly the course the original poster mentioned...
Answer: I would like to suggest the tutorial from Christopher Bishop. Just search for the name and probabilistic graphical model. You will find it. Christopher Bishop is the author of Pattern Recognition and Machine Learning. He has provided a free downloadable pdf of the book chapter on probabilistic graphical model from his website and lectures on this topic including at the Machine Learning Summer School in 2013, held at the Max Planck Institute for Intelligent Systems.
Also, I used the presentations from some other universities on this topic, which may have a number of various course names such as the introduction to graphical models. You may find one that suits your needs.


Mirroring iPhone 6s to MacBook Pro without Airplay

Question: I want to mirror a video-streaming app from my phone to my MacBook Pro (an app that unfortunately is not available for laptops, just iPhone and iPad). Airplay won't work for this. Need the USB port free on my computer to be able to use a projector in tandem with the phone/MacBook. I don't mind paying a few bucks for an additional app, but I need something clean and reliable that is relatively easy to set up for a relative computer illiterate like myself.
Answer: After doing a bit of searching, I came up with Mirroring Assist. Seems like a good app to use in your case.
It depends on Mirroring360 software installed on the Mac/PC (7 days trial, full-featured) or an Apple TV.
Comment: This worked perfectly, thank you so much for your help!
Comment: I don't understand. The title of this thread says "Mirroring iPhone 6s to MacBook Pro ***without Airplay***". I tried both MirroringAssist and Mirroring360 - they both require the use of Airplay :(


Setting slower shutter speeds for canon 5d mark ii

Question: How do I set shutters speeds slower than 1/30 on canon 5d markII ? In the manual setting I cannot seem to scroll down slower than 1/30.
Comment: I strongly suspect you're setting a shutter speed of 30s, not 1/30s. What is the display actually showing?
Comment: Having the same issue. It's definitely limiting shutter speed to 1/30 of a second, not 30". Bulb is not the answer because there is not precise control for longer exposure times. Must be some kind of glitch or settings issue...not sure what's happening. Please help!
Answer: If the top of camera LCD display and viewfinder are showing [30"] (without the brackets) the selected shutter speed is 30 seconds which is the same as one-half minute. For shutter speeds slower than 30 seconds you will need to use Bulb mode (B on the Mode Dial) and time the shot with a watch or use a cable release with a built in timer.
If the display in the viewfinder and top of camera LCD is showing [30] (without the brackets) the selected shutter speed is 1/30 second.
On quick way to double check is to use the Quick Control screen. While shooting in M or Tv mode press the small, 8-way button at the top right of the LCD screen on the back of the camera straight down. The Quick control screen will appear on the LCD and the selected shutter speed (Tv) will be displayed in the upper left corner. If you have selected a speed of 1/4 second or shorter the Tv will be displayed as a fraction [1/30]. For shutter speeds between 1/4 and 1 second the display will show [0"] followed by a number denoting tenths of seconds. So [0"3] is 3/10 seconds, [0"4] is 4/10 seconds, and so on. If you have selected a shutter time of one second or longer, the number of seconds followed by ["] and then tenths of seconds, if any, will be displayed [30"]
Another way to see the Quick Control Screen is to use the Custom Functions to map the SET button to turn on the Quick Control Screen. Set C. Fn IV:3 (Assign SET Button) to option 5: Quick Control screen. When in normal shooting mode press the Set button in the middle of the large control dial on the back of the camera to turn on the Quick Control Screen.
Answer: You need to go to settings and change the Live View setting in the "Live View/Movie Func set" menu, and change "LV Func Setting" from "Stills+movie" to "Stills only". This will unlock shutter speed in LV mode, which is locked due to the selected movie framerate when movie recording is enabled. You'll need to re-enable "Stills+movie" in order to record videos.
Answer: Select B on the mode dial, not M.  The 5DMkII has an explicit bulb mode setting, so you don't have to scroll past 30" to get to bulb mode. In Bulb mode, you can then hold down the shutter button for the duration of shutter speed you want, or use a cable release with a lock.  The top LCD panel displays a count of the seconds that the shutter is open.
Answer: Take it out of live view mode and you'll be able to have free range of shutter speed. Seems like Live view is limited to 30


Is local non-satiation enough to talk about Walrasian Equilibrium being subset of Core

Question: In Advanced Microeconomic Theory, the author mentions that the Cobb Douglas utility function is neither strongly increasing nor strictly quasiconcave over all of R+. But the condition of strongly increasing in R+ is used to prove that set of Walrasian Equilibrium allocations is a subset of Core. So we can't apply this result to Cobb Douglas utility functions to prove that Walrasian Equilibrium obtained is part of core. Is local non satiation sufficient to say set of Walrasian Equilibrium allocations is a subset of Core as Cobb Douglas satisfies local non satiation?
Comment: Depending on how you define the core, no assumption whatsoever is needed. You don't need any assumption to show that not every consumer can be made strictly better off in a Walrasian equilibrium.
Comment: @MichaelGreinecker Write a short answer?
Answer: There are two standard ways to define the core of a (finite) exchange economy. The first version says that there is no coalition, no nonempty set of agents, such that everyone in the coalition can be made better off by just using the total endowment of the coalition. The second version requires that there is no coalition such that someone in the coalition can be made better off without making anyone in the coalition worse off by just using the total endowment of the coalition.
Clearly, if the second version holds, so does the first one. That every equilibrium allocation satisfies the second version can be proven exactly as one proves the first welfare theorem. It requires an assumption like local non-satiation, just like the first welfare theorem requires. That every equilibrium allocation satisfies the first version requires no assumption whatsoever; it follows directly from the definition of equilibrium: If one makes everyone in a coalition better off than what they get in an equilibrium allocation, everyone must consume a more expensive commodity bundle. But this implies that the price of the total consumption of the coalition exceeds the price of the total endowment of the coalition, which is not possible if the total consumption rquals the total endowment.


I want to replace two switches controlling one track with one

Question: The track has four lights on it. Two lights are controlled seperatly by two switches running to the same track. I am upgrading to LED, and want to only use one switch for the track. Can I simply cap and tape off the extra black and white wires, and ignore the extra switch, or will this cause some other problem, like power continuing through the wires.
Comment: Just to be clear: do you have a 2 circuit track controlled by two single pole switches?  Or do you have a single circuit track controlled by 2 switches?
Comment: It is a two circuit track controlled by two single pole switches.
Comment: @AndrewGarrity, please upvote any helpful answers and accept one if it answered your question so that the question can be resolved.
Answer: There won't be any "extra" wires if you do the job correctly.  Currently (I'm guessing), each switch has a hot input and the switched output black wire which goes to the lights.  The white neutrals are all tied together somewhere.  What you need to do is cap off the hot lead to the switch you're removing (make sure this capped dead-end wire remains inside the box) and move the output wire from that switch over to the output post on the remaining switch. If you're just going to leave the dead switch in-place, then you're done.
If your concern was about leaving that switch "live," then certainly you should not do that (cap the hot lead as I wrote above)
Answer: Assuming that both switches are in the same box you can nut them together with a pigtail going to the switch terminal, or if the switch has both a screw down and a push in terminal you can use one for one light and the other for the other light.  If the switches are in different locations then you'll have to run a cable from the switch you want to use to either the light or the other box.  What to do with the existing cable depends on which location you take the new cable to.


Why is my website going blank everytime I edit a row in Wp_options?

Question: I have a wordpress theme and I am trying to change a bit of text that I can only really find in the database. It's a bit of title text that I can only find in the wp_options database.
I found the bit of text I need to change in wp_options, in a row under "of_options"
<code>...";s:16:"translation_port";s:16:"Recent portfolio";s:23:"translation_relatedpost";
s:7:"Related"; s:27:"translation_advertise_title";s:28:"Our Nights";
s:20:"translation_morelink";s:9:"Read more";s:24:"port_project_description";s:20:
</code>
That above code does not have any breaks in it, I only changed it for ease of reading.
Just ran another test, and I dont actually have to change a single bit of text, purely opening the row for edit, then saving it without touching anything messes it up.
No logos, images, layout or anything shows. Only the background image :/
I have no idea, tried everything.
Any help would be appreciated.
Answer: Don't try to edit this field in the database.
What you see here is a serialized array.
'of_options' refers to 'Options Framework' and is an array containing all chosen options.
Look under Appearance for an options links. The values will be editable there. If somewhere else you need to add more info to your question for help to be provided.
Comment: I just need a way to edit the serialized data without it destroying my site :/

This is the outcome http://i.imgur.com/2uQn2lw.png
Answer: Never fully read it.
Was a part in the theme edit menu to change the titles under a translation tab. My bad.


Why does my Codeblock only display output for less than second..?

Question: I installed Codeblock a week ago and have not changed any setting. I created a simple console application and when I clicked build and run it display my output for like milisecond and disappear... It used to stay forever until I exit it. Anyone know why is this happening? In the Build log tab it says "Process terminated with status 0 (0minnutes, 0 seconds)
Comment: Let me guess; you are using MS-Windows, when you run the application, the console opens and closes immediatly afterward? That's because console applications are meant to be executed by typing the programm name into a running console window, not by clicking on the application icon. For debugging purposes, you can add some code at the end that waits for a key press.
Comment: Does your output appears and disappears in about 0.1s, I guess you need to look for the output window in your codeblocks application.
Answer: You don't have any problem actually, neither in your Codeblocks Application nor in your code, But codeblocks doesn't wait for you to close its console window manually, It automatically does it.
You've 3 ways, choose that suits you better

Go to Menu Bar and toggle 'show output window'
Alternatively you can append a C++ code that waits for an event to happen, so that you may get enough time to watch your Output.
You can use the code which I've given below
It will be definitely good if you choose to see your output message through debugging(Step Over). It will also improve your debugging skills.

If you want to choose second approach then append following code in your application
#include<conio.h>
int main()
{
    // After your code - write
    getch();
    return 0;
}

Note:- I believe you're using codeblocks on Windows Platform, this code will work fine on windows, but <conio.h>
won't be available to you if you want to port your program from Windows to Linux
I'll recommend you to give them preference in this order [3 > 1 > 2]
Answer: for those who may encounter this error:
all you need to do to make the console not dissapear is this:

go to project properties.
click on build targets
there is an option below console application  "pause when execution ends"
check it and you are good to go!

Hope this helps
Answer: Use :
#include <iostream>
//...other includes....
int main()
{
   /*Your Code */
   //...
   std::cin.ignore(); //wait for Enter, will makes the console to stay.
}

Answer: You may be clicking on the red arrow, however click on the "build an run" arrow instead, which has a little cog and a green arrow.
Comment: Please do not answer with a comment/question. Understandably, your rep is too low to comment, but that still does not mean answers should be used to make comments as an alternative. It would be preferable if you deleted this.
Answer: Solution if you are copying and pasting input: For me, the issue was that I was copying and pasting my input file from the web. Presumably, this copied some invisible characters, such as a return, which my program registered as the user having pressed any key to continue. The solution I used was to download the file to my computer, then run my program in command prompt, piping the input into the .exe file in the following manner:
C:\Project Directory> myProgram.exe < myInputFile.txt

Many of my professors recommend running programs from the command line, and I advise using this tactic as it is quick and lets you skip manual typing. Also, you can save the output of your program to a desired file, rather than having it print on the command line, by doing the following:
C:\Project Directory> myProgram.exe < myInputFile.txt > programOutput.txt

Hope this helps.


Windows apache log reader

Question: I am looking for a simple log reader, not something like awstats.
Just a program that I can have on my computer, download the log file through ftp, open the program, and eg.
see how many times a specific .zip file has been downloaded.
Answer: Grep (yes, it's available for windows) would make quick work of that.
Comment: hmm, that download link is broken...
Comment: Fixed. (7 characters)
Answer: Found one: http://www.weblogexpert.com/

Windows apache log reader


How do I add the NULL device to Windows XP Embedded?

Question: Windows XP Embedded is missing the NULL or "NUL" device.  For one thing, Visual Studio seems to require it and trying to build a project aborts with a PRJ0015 error.
Anyone know how to configure an XPe image to include support for the NUL device?
Answer: "Null Device Driver" is available in the XPe Target Designer, but it's normally hidden. Apparently each component has a visibility level, and if it's lower than that set in the Target Designer options (Tools->Options), it's hidden. Null Device Driver is at level 200, so I set the level to 100 and could see it and install it.
Answer: There's another important situation where you're going to want the NUL device: if you're installing some or all of the Cygwin UNIX solutions for Windows.  In particular, if you're doing something like, oh, I don't know, to pick a completely random example, trying to put an SSH server on the damned thing so you can, just on a lark, say, log in and maintain it.
That's right-- Cygwin actually maps its UNIX /dev/null device to the Windows NUL device.  You know, for maximum compatibility.  Just in case the platform-specific implementation of IMMEDIATELY THROWING DATA INTO THE TOILET AND OBLITERATING IT, NEVER TO BE SEEN AGAIN, UNTIL THE HEAT DEATH OF THE UNIVERSE, happened to be novel and innovative.
While cygwin will INSTALL without NUL available, it will not, in fact, actually enjoy a typical work day.  This is most evident the first time you try to launch a bash shell, and notice a slew of error messages about /dev/null resulting in no such file or directory errors.  One presumes the device is perhaps actually just an NTFS link, but who knows.
In any case, the fix is to add the "Null Device Driver" component, helpfully located under Software -> System -> Other, a surprisingly small category which also contains such useful components as Internet Checkers, the Schedule Service Command Line Utility, the 1394 Kernel Debugger Support Library, EBCDIC support for Microsoft Bob, some cheat codes for Zork, and the code pages to say "(A)bort, (R)etry, (I)gnore, (F)ail?" in Muppet Swedish ("(B)ork, b(o)rk, bo(r)k, bor(k)?")
Hope this helps,
   Matt "Breakpoint" Heck
Answer: Running Visual Studio itself on XP Embedded doesn't seem like it'd be supported.  You should build on a full OS and then just deploy your application to XP embedded.


All translations of classical logic into intuitionistic logic

Question: What are all possible ways of translating classical logic into intuitionistic logic? That is, if $S$ is the collection of sentences of first order logic, what are all the functions $f : S \to S$ such that $\Gamma \vdash_c \phi$ if and only if $f(\Gamma) \vdash_i f(\phi)$? I know that there is a couple of variants of double negation translation. So, two questions: is there a classification of all possible translations? Are they all logically equivalent to double negation translation?
Comment: @fhyve: if $f_0$ is any translation and $\phi$ is any formula, consider $f(\phi) := f_0(\phi)\land \psi$. This is a translation if and only if $\vdash_i \psi$.  Now consider $g(\phi)$ defined so that $g(\phi) := f(\phi)$ if there is no proof of $\lnot\text{Con}(ZFC)$ with fewer than $|\phi|$ symbols, and $g(\phi) := (0=1)$ otherwise. Then $g$ is a translation if and only if  $\text{Con}(ZFC)$.  All the functions I have defined here are primitive recursive. So, unless we find some narrower type of translation that is easier to handle, it will be very hard to characterize translations.
Comment: You probably want to also demand that $f(\varphi)$ has the same nonlogical symbols as $\varphi$, to avoid silliness like "$f(\varphi)$ applies the double negation translation, but then swaps the unary relation symbols "$U$" and "$V$"."
Comment: Even telling whether a given function is a translation will be difficult, for several reasons. I doubt there will be a very nice, general classification.
Comment: @CarlMummert Why is that? And then can we at least give large classes of examples?
Comment: To show how much the answer to this question really depends on the exact definition of the class of things that count as 'translations', it is worth recalling that there is a result by Wójcicki according to which the consequence relation of classical logic cannot be faithfully embedded (or 'conservatively translated') by any connective-by-connective (or 'homophonic') translation into that of intuitionistic logic. [Here](http://profilesarts.wpengine.netdna-cdn.com/lloyd-humberstone/files/2012/07/lhumberstone-7contra99.pdf) is a paper that can be checked for a stronger version of this result.
Answer: Remember that the set of theorems of intuitionistic logic is a proper subset of the set of theorems of classical logic. So, if you want to translate every classical theorem to an intuitionistic version you will fail in general.
Comment: This doesn't actually address the question - I think you misunderstand what a "translation" means in this context. Keep in mind that there **are** translations, such as the double-negation translation mentioned.
Comment: While $\phi$ being a classical theorem doesn't imply $\phi$ being an intuitionistic theorem, that doesn't preclude the possibility that there is a way of transforming every classical $\phi$ to some $f(\phi)$ such that if $\phi$ is a classical theorem, then $f(\phi)$ is an intuitionistic theorem. In fact, there are many such $f$, such as the usual double negation translation, which is roughly $f(\phi) = \neg \neg \phi$ (you still need to define how it interacts with operators).


How to get property types of a given Entity type in Xodus?

Question: Is there a way for Xodus API to check the type of property?
Xodus have a method txn.getEntityTypes(); but I have not found a way to get the property types of a given Entity Type, is that possible?
Answer: There is no way to get property types of a given entity type. In case if all entities of the given entity type have the same set of properties, one can take an entity of given entity type and use method "entity.getPropertyNames()".
Comment: We have a API that let's client write data with flexible types, but I want to prevent a property to be saved with different type, for example if a property is already set to be String then it should not allow to save other types, like a Number or Object, just String will be allowed, for reasons that you have said before if two property are different then it would break find
Comment: @xybrek there is no possibility to check types that way out-of-the-box.
Comment: Thanks, we have solved this with the approach in this answer, getting the properties and iterating over it checking the value types


how to intercept the command that launches a bash script

Question: If I run a bash script from the command line (with root permissions), is it possible to intercept the boot command within the script (while the script is still running) in order to log it?
I try to be clearer. From the command line I launch a script with this statement: ./reconfig.sh -host localhost ... and other parameters. Inside the script, while it is running, a log file is written and I would also like to log the launch command inside it.
Comment: What do you mean by 'the boot command' and  'while the script is still running'? Please tell us more details, and please give feedback to the answers and comments. Otherwise we can only guess, and the answer(s) might or might not be useful for your particular case.
Comment: I still can't really understand, what you really want. If you want to log something from the command line, the `logger` command can do it ( http://man7.org/linux/man-pages/man1/logger.1.html ). More luck on the site!
Answer: If editing the script is an option, you can add "logger" commands to log whatever you'd like to the system's logs.
on my Fedora system,
/usr/bin/logger $USER just ran $0
run from a bash prompt, added a log entry with the current timestamp, a source of my login ID[PID of logger command]  just ran bash
you could add whatever information you wanted into that logger command's message.  You can even pipe standard out of another command to the logger command.
$0 is a special variable that holds the name of the command currently running (bash when sitting at the bash prompt, but in a script, it would be the script's filename)
If you have access to the .bashrc or other startup files for the user who will be running processes you want to log, you could also create an alias.
I just tried:

alias logls='/usr/bin/logger listing a dir ; ls'

then logls
and got the listing of the current directory, and a timestamped log entry in the system logs.
if the alias was set to the same name as the original script it would be pretty transparent to the user(s).  You would likely have to specify the full path to the original script in the definition of the alias of course.


Core-Equivalence Theorem (Debreu-Scarf Theorem) Intuition

Question: The theorem states that if preferences are strictly convex and strongly monotone, then the Core eventually shrinks to the Competitive equilibrium as you replicate the economy enough times. How is this happening intuitively? Is it that you can form more richer coalitions and are able to block more and more core allocations?
Answer: I'm not sure this counts as intuition but is the logic of the proof and related proofs. I will purposefully confuse agents and types in what follows, since the logic works also in a limit models with a continuum of agents or for sequences of not necessarily replicas.
A competitive equilibrium is a feasible allocation together with a price system such that the consumption of an agent does not cost more than their endowment and everything better costs more. We will focus on the latter part first.
Suppose you have an allocation $x$ that is in the core of every replica of the economy. Clearly, it is feasible. We have to find a price system that supports it. That trick is that we want to find a price system $p$, such that for every agent $i$ every commodity bundle $y$ such that $y\succ_i x_i$ one has $p\cdot y>p\cdot \omega_i$. One can alsways write $y$ as $\omega_i+z$ with $z=y-\omega_i$. Then the problem reduces to showing that for every $z$ such that $z+\omega_i\succ_i x_i$ one has $p\cdot z>0$. We want that all beneficial net trade vectors have a positive price. So let $$Z=\{z\in\mathbb{R}^l\mid z+\omega_i\succ_i x_i\text{ for some agent } i\}.$$
The tool of choice to make a set of commodity bundels have a positive price is to use the separating hyperplane theorem. For this we have to separate it from some other convex set, and the strictly negative orthant $-\mathbb{R}^l_{++}$ works well.   No element of the strictly negative orthant can be in $Z$. For then there would be some $i$ such that $z+\omega_i\succ_i x_i$. But since $z\in -\mathbb{R}^l_{++}$, we have $z+\omega_i\ll\omega_i$. By strict monotonicity, $\omega_i\succ_i z+\omega_i$. By transitivity $\omega_i\succ_i x_i$. But then the coalition consisting of $i$ alone could block the allocation $x$, in contradicition to $x$ being in the core of every replica. So $Z\cap -\mathbb{R}^l_{++}=\emptyset$.
However, the  set $Z$ need not be convex, so we try to separate the convex hull $\text{con(Z)}$ from $-\mathbb{R}^l_{++}$. This need not work in general, the difference between $Z$ and $\text{con(Z)}$ can be quite large. But for large replicas, an element of $-\mathbb{R}^l_{++}$ cannot be in the convex hull of $Z$ either. Otherwise, there would be a strictly negative vector that is a convex combination of elements with rational coefficients. So suppose $z,z'\in Z$, $\alpha$ is a rational number between $0$ and $1$ and $\alpha  z + (1-\alpha)z'\in -\mathbb{R}^l_{++}$. So write $\alpha$ as $p/q$.
Now pick $q$ agents, $p$ of which would prefer $z$ plus their endowment to what they get, and $q-p$ who would prefer $z'$. If one gives them exactly that, they would receive on average $\alpha  z + (1-\alpha)z'\in -\mathbb{R}^l_{++}$. So they would be better and one could even dipose of something left. Or one distributes what is left among the agents, who prefer it even more because of monotonicity.
Now, the argument has not used that preferences are convex. The convexity assumption is only needed to prove the equal treatment property one needs to phrase everything in terms of replicas. There are versions of the argument not based on exact replicas that do without any convexity assumption. One can also make the argument work when preferences are not transitive, but this requires a bit more effort.
Answer: I can try and explain how the core shrinks using an example:
Consider a pure exchange economy with two consumers $A$ and $B$ and two goods $X$ and $Y$. $A$ has an endowment of $1$ unit of $X$ and $B$'s endowment is $1$ unit of $Y$. So, $\omega_A = (1,0)$ and $\omega_B = (0,1)$. Suppose utility functions of $A$ and $B$ are identical and of this form:
$u_A(x_A, y_A) = x_Ay_A$ and $u_B(x_B, y_B) = x_By_B$.
In this set up, an allocation where $A$ consumes everything and $B$ consumes nothing is a core allocation.
Now let us consider a 2-replica of the above economy. We now have two agents of type-A and 2 agents of type-B. If we now consider the allocation where type-A consumes $(1,1)$ each and type-B consumes nothing. This allocation will no longer be in the core, because one type-A agent and two type-B agents can redivide their total endowment of 1 unit of X and 2 units of Y to make everyone in the group better off. We can consider this division: type-A gets $(1-2\epsilon, 2- 2\epsilon)$ and each of the type-B agent gets $(\epsilon, \epsilon)$. For $\epsilon$ small enough this works.


Why is this site so inactive?

Question: I have noticed a lot of inactivity here; there are next to no questions being answered or asked. Why is that? What can we as the members of the site do to change that?
Answer: While it is surely true that this community is not very active, the amount of unanswered questions is pretty low (less than 5%) and no reason to worry. Answers, especially good answers, take some time, so have a little bit of patience with the community.
P.S. You may also think of other means to elicit more and faster answers, like promoting your questions on other social media, or offering a bounty.
Answer: This is a personal opinion, so take it with a grain of salt.
I think there are a few reasons for this, in no particular order:

Making or studying constructed languages is not a common hobby.
I'm pretty sure that most conlang enthusiasts enjoy sharing and getting feedback on their own creations, and Stack Exchange Q&A is not a good format for this.
There isn't a standard way to get into the hobby and there isn't a common core of knowledge that everyone is supposed to know.

Also, peoples' interest might be narrower than the scope of the site as a whole. For example, I'm interested in things that make learning an auxlang as a second language easy or difficult and less interested in conlangs tied to a specific work of fiction.
There's also another perspective to consider. The question quality on this site is fairly high. Relaxing some of the restrictions inherited from Stack Exchange might increase traffic, but it would also change the character of the site.
Comment: I would note that reducing expectations of quality is a non-starter, simply because this is SE. Each forum represents SE as a whole within its broader community, and since SE itself seeks to be **THE** high quality Q&A site, it follows that all forums will strive for high quality. Essentially, high quality & low activity is better than low quality & high activity.

Why is this site so inactive?


How old is Samantha?

Question: In one episode of Bewitched, we see a painting of Samantha (we assume it's Samantha) which is set in old Salem by the looks of it.  This then raises the question of how old Samantha actually is, but the question is never truly addressed.  So, how old is Samantha at the time of the series (educated guesses are acceptable).
Comment: Both the questions you've asked are explitly answered in the Bewitched online magazine; www.harpiesbizarre.com. You may wish to give it a read...
Answer: There is a very extensive analysis of contextual clues from the episodes as to the various ages of the witches at Bewitched @ Harpies Bizarre:

In # 3, Endora makes reference to having known Diogenes (400 BC).
In # 5, Endora makes reference to having known Julius Caesar.
In # 23, Endora says she cooked for the Roman Emperor, Claudius.
In # 24, Endora makes reference to having known Helen of Troy (1180 BC).
In # 160, Serena tells Phyllis that Endora admits to 1000.
In # 168, Maurice says he and Endora knew Atilla the Hun (450 AD).
In # 210, Endora says she has changed her mind many times in 3000 years.
On the other hand:
In # 171, Endora says she went to Shakespeare's plays as a little girl.
In # 175, Endora refers to being a child bride when Samantha was born.
In # 203, Endora again says she was a child bride. This time she defines it as being in 1670.
In # 230, Endora says she was not born at the time of King Henry VIII (1570).

Ignoring the fact that several episodes specifically contradict each other, the general theme is that Endora is at least 3000 years old and that Samantha was (probably) born sometime between 1570 and 1600 which would make her approximately 390-400 years old at the time of filming.
Comment: If you want a closer date, the biblical Witch of Endor who summoned a spirit for King Saul is supposed to be Endora - thus the name. So this would give some 2700ish years if she was young at the time.
Comment: @Oldcat - Again, context clues would suggest that witches are considered children for a hundred (or more) years.
Answer: When Darrin went back in time to save Samantha from Henry VIII, Endorra said she had powers to get them there and back because during the time of Henry VIII, she had not yet been born.  So she was no older than 500-ish
Comment: @JRE - My take on it is that she's "very old" and that the writers were simply *inconsistent from one episode to the next* over the space of 250+ episodes, written at a time when computers were a rarity and being able to copy-check prior episodes meant getting them out of the studio library and re-reading them
Comment: This appears to relate to episode #230 (*How Not to Lose Your Head to Henry VIII: Part 2*), As I've noted in my answer above, this directly contradicts other statements that Endora has made in prior episodes.
Comment: @Valorum:  Since witches can obviously time travel, there's no reason Endora had to have been born 3000 years ago in order to have known someone from that far back. The only thing that directly contradicts 500 years old and your list of "age indicators" is the one statement about Endora changing her mind a lot of times over 3000 years.

How old is Samantha?


Resizing png without pixelation

Question: I have a png that I need to resize to different sizes. Would it work for me to paste it in illustrator, use its auto vectorizing tool to vectorize it, and then resize it?
Comment: What's the image of? Is it a drawing, a photo, a scientific diagram, or other?
Comment: Could you provide us with the image? It's very hard to answer without "eyeballing" the specimen first…
Answer: Yes. Sort of. Whilst there's all manner of tracing tools around the world, none of them are that great. So you'll have to do some cleanup and tidying of the vector, more than likely.
Even if it's just a circle.
They're software guestimates. Not scientific perfection.
Answer: If it's simple enough I'd recreate the image from scratch using the png as a guide, then resize the vector. Illustrator's auto vectorizing tool is great, but I always have to do some form of cleanup and that just annoys me.
Answer: If you want to size the png UP you will have to recreate the entire thing if you care that much about pixellation.
If you are only sizing the png down (This assumes you have a higher-quality or large-sized png) You can turn your full-sized PNG into a smart object in photoshop, then you won't have to touch illustrator.  When you make your png a smart object, you can resize it down (smaller) as much and as many times as you would like.  You can even resize it up after you've resized it down, assuming you don't go over the original size.

Resizing png without pixelation


Relationship between the  and  tags in HTML5

Question: The  element can also be used to wrap a section's table of contents, a search form, or any relevant logos.
Comment: What is your question?
Answer: I know it's confusing. The head element contains meta data about the document. The header element contains any items that should contain introductory information and often includes things like h1 elements, logos, and things about the author or company. Very often, it will also contain a navigation bar. The h1 tag stands for heading and helps to structure your document and tell web browsers/screen readers and others the importance of that element.
Answer: I would explain this by an example.
A lion living in a jungle marks its territory and no other male is allowed to rule there. In the same way,  tag is a territory where the header information is put and  tag is used to highlight the lion i.e the important statement, title , etc.


Is it okay to ask a professor from another university for class lecture notes of a course that he offered on that university?

Question: I find two very interesting courses that were offered in the Spring 2019 semester at ETH Zürich. Unfortunately, their class lecture notes are not shared publically. I wonder if it is appropriate to email the professors and ask them for class notes.
Comment: Will they want to give their work for free? Will you give away your work for free in the future?
Answer: You can always ask as long as you are polite.  There are many reasons that an instructor wouldn't want to release their notes, though.  Among them (there are others):

Their notes are copyrighted and don't belong to them, either because THEY are using another person's notes or because their notes are part of a textbook that they wrote and signed copyright over to.
Their notes include important assignment information for assignments that are given every year, so they don't want them in the wild
They want to protect their copyright and just straight up don't want to give you the notes

I, personally, would have no issue giving my notes out to anyone who asks, but I'd give the big caveat that you can probably find better resources.  Other instructors may just ignore you.  However, a polite query is fine.
Comment: Some people might be more willing to share them with another professor than with a student, I think. But there is no harm in asking.
Comment: Another possibility is that there simply aren't any notes!  In a class where I know the material well enough, I frequently lecture extemporaneously at the blackboard.  I might have written down an outline for the lecture (if it's too complicated to remember or I'm worried I'll forget about a key point) or the specifics of a couple good examples (say some specific matrices to find the eigenvectors for), but that's it.


Should we add a historical lock to, or delete this old upvoted question?

Question: This question about planning perk point allocation is pretty clearly off topic, however it is upvoted quite a bit (+20), has 46k+ views, and has quite a bit of good information. To delete it, it would take 5 delete votes to get rid of it, and delete votes can take a long time to come (there are a number of closed questions that are years old that still need a deletion vote). We have historically locked similar questions in the past, so the question is should we lock it or delete it? Either action will probably require a mod hammer.
Answer: The reason for the question off-topic is being opinion based. Per our guidelines, a question should be objective rather subjective to be on-topic. Even though is off-topic, it attracted many views, upvotes, and overall good information for future viewers.
From what I have seen, an off-topic question may be good in general terms, but they attract downvotes solely for the fact of being off-topic. This question only has a single negative downvote.
The fact the question is 6 years old, but only closed within the past 6 months shows how many users found the information useful, despite being off-topic. If the question is deleted, then the information will be lost without the proper privileges
My vote is have a moderator cast the historical lock on the question. The question matches 3 out the 4 criteria for a good historical lock candidate.

The post does not meet the current guidelines for a good, on-topic question, and

The post is stellar, in spite of its off-topic nature, and

There are a large number of views, upvotes and inbound links on the post

The fourth criteria states the question should be go through a cycle of close/open or delete/undelete at least once. However, a comment mentions users frequently desire questions to be locked without being reopened or undeleted. In this case, I am one of those users.
Comment: Agreed, and done, for the reasons stated in this answer :-)
Comment: This was my thought as well. It has good info, but is off topic for our site. I had raised a mod flag on it that was marked as helpful, but nothing was done, so I figured I'd ask the community for input.
Comment: @Dragonrage Good call. Now we wait and see what other users have to say