Puzzling leak in my 2nd floor tile shower

Question: I am looking for help.  I recently bought a home.  During the home inspection the inspector plugged the shower drain, filled the shower to test the shower for leaks.  Unfortunately, I believe he used water from the shower vs another source.  Within 20-30 minutes water began leaking into the kitchen below through the can lights. (Leak is being conservative, actually was a lot of water coming down). What's more, a puddle of water formed on the front porch, which is at the front of the house whereas the shower is at the back of the house. However, there was/is no evidence of water leakage or staining on the ceiling of the first floor.   After talking to several contractors/plumbers all thought it was the shower pan.  Well, upon removal of the tile floor and pan, there is absolutely no indication of water damage, stains, etc on the sub floor our surrounding framing material. The contractor is concerned, as he expected to see water stains at a minimum.  In addition, given the volume of water coming down and the size of the puddle on the front porch, a lot of water is escaping from somewhere. Anyone have any idea what the next step should be?  Could it be the drain?  Seems like if it were the supply pipes the leak would be constant.
Comment: This question confuses me greatly.  Please edit it, insert paragraph breaks, and read your question from the mindset of, "What will a person who has no idea what I'm talking about think I'm asking?"
Comment: Was the drain to the shower plugged for the 20-30 minutes while the puddles were forming, or was the water released from the shower during that time?
Comment: Could be coming from the plumbing between the faucet and the tap (in which case you'd probably see signs of it near that location), or the drain line (in which case it could be anywhere along the length of the drain).
Answer: For any leak, you have to find the source, and also note that leaks travel along surfaces so sometimes where the water is seen is not directly under the leak.  Often this will involve cutting up walls and causing more water damage.
You need to find out if the leak is coming from a supply line or waste line, and also when the leak occurs.
First thing - when there is no water running and no water in the tub, is there a leak?  If so the leak is before a fixture in a supply pipe.
Now plug the tub and fill it up.  While the water is running (but not draining), is there water leaking?  If so, the leak is at or beyond the shower valve and possibly in the shower itself.  You mention that the leak is pretty big, so if present at this point, stop filling the tub and watch to see if the volume of the leak subsides. If so it could be a leak in one of the shower valve fittings or the diverter stem, or it could be water splashing up and getting behind the tile.  In this case your best bet is to open the wall behind the shower (if possible) and look for leaks.
If the water is still running with the tub full but off then the leak is in the drain pan.
If not, pull the plug and check again for leaks.  If you see water now, the leak is in a waste pipe. This is the scenario where you can end up cutting lots of drywall to find the source.  Start at the tub and go from there, follow the pipe.
If the drywall/plaster is already water damaged, you may as well rip it out before it grows mold - you are going to have to replace it anyways.
Answer: I too recently had a leak from my tub/shower. Checked the drain line, cut the walls checked supply lines nothing. Finally found my leak. My tub was not sitting level so the water from taking a shower was running to a corner of the tub and going over the edge of the tub onto my floor. The unevenness of my tub was never noticeable and I always thought the water in that area was from the kids taking showers and splashing the water or not closing the shower curtain properly.
Comment: Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably [take our tour](//diy.stackexchange.com/tour) so you'll know the details of contributing here.


selection checkbox for ag-grid table

Question: I want to have the selection checkbox for ag-grid with the option below:
But didn't see the checkbox on the left. Have any idea what else needs to be settings to make the selection checkbox works.
self.appliancesInGroupGridOpts = {
        angularCompileRows: true,
        enableColResize : true,
        rowData: null,
        checkboxSelection: true,
        enableSorting: true,
        columnDefs: [
          {
            valueGetter: 'data.name',
            headerName: $filter('translate')('APPLIANCE.NAME'),
            suppressSizeToFit : true,
            template: '{{data.name}}',
            checkboxSelection: true,
            width: 200
          } ,
           {
            valueGetter: 'data.updated',
            headerName: $filter('translate')('APPLIANCE_GROUP.PUBLISH.MODIFICATION_TIME'),
            suppressSizeToFit : true,
            template: '{{data.updated}}',
            checkboxSelection: true,
            width: 200
          }
        ] ,

Answer: http://www.ag-grid.com/angular-grid-selection/index.php
Checkbox selection can be used in two places:

row selection
group selection.

To include checkbox selection for a column, set the attribute
columnDefs: [{
    valueGetter: 'data.name',
    headerName: $filter('translate')('APPLIANCE.NAME'),
    suppressSizeToFit : true,
    template: '{{data.name}}',
    width: 200,
    checkboxSelection: true
    ...

on the column definition.
You can set this attribute on as many columns as you like, however, it doesn't make sense to have it in more one column in a table.
To enable checkbox selection for groups, set the attribute:
groupColumnDef: {
    headerName: "Athlete",
    field: "athlete",
    width: 200,
    cellRenderer: {
        renderer: "group",
        checkbox: true
    }
}

for the group renderer. See the grouping section for details on the group renderer.
Selecting groups can have the effect of selecting the group row, or selecting all the children in the group. This is done by setting the attribute:
groupSelectsChildren: {true || false}

When set to false, then selecting the group will select the group node.
When set to true, then selecting the group will either select or deselect all of the children.

The example below shows checkbox selection with groups. Selecting the group has the effect of selecting the children. Likewise selecting all the children automatically selects the group. In this scenario the group itself will never appear in the selectedRows list.
The example also shows a checkbox for selection on the age column. In practice, it is not normal to have more than two columns for selection, the below is just for demonstration. Having a checkbox within a non-group row is best for grids that are not using grouping.
In Addition: you could add this on the col definition
checkboxSelection:
Set to true to render a selection checkbox in the column.
Answer: What say einav is true however i think he forgot the very base :
set the property rowSelection:'single' or rowSelection:'multiple' on gridOptions if you want to have selection enabled :)
The attribute checkboxSelection is only for columns not grid options.

The following properties are relevant to selection:
rowSelection: Type of row selection, set to either 'single' or 'multiple' to enable selection.
rowDeselection: Set to true or false. If true, then rows will be deselected if you hold down ctrl + click the row. Normal behaviour with the grid disallows deselection of nodes (ie once a node is selected, it remains selected until another row is selected in it's place).
suppressRowClickSelection: If true, rows won't be selected when clicked. Use, for example, when you want checkbox selection, and don't want to also select when the row is clicked.

From the same link given by Einav

selection checkbox for ag-grid table


Is the Wi-Fi symbol always supposed to have "full connection"

Question: The symbol in the top bar always shows the 4 bars, when WIFI is activated. Is this normal, or should it (as on iPhone) represent the WIFI strength?
Comment: You can see Wi-Fi strength only in Wi-fi option where you can set it on or off.
Answer: This is normal - it does not represent the signal strength, but only whether it's active or not. (There's also an animation when it's attempting to connect to a WiFi network)
Edit
This behavior was changed in the Windows Phone 8.1.
Now the WiFi signal on top of screen shows the power strength as in the WiFi settings menu.
Answer: It will always be full when connected, regardless of signal strength.
Here is a break down of the three Wi-Fi related icons in the status bar (full list of status icons):
 Connected to a Wi-Fi network. The icon is animated when your phone is trying to connect to a Wi-Fi network.
 Wi-Fi is turned on, but your phone isn't connected to a Wi-Fi network.
 Cellular data connection is shared with other devices over Wi-Fi.


Biblatex - Texmaker auto-complete commands

Question: Is there a way to employ auto-completion for Biblatex commands (not entries) in Texmaker without writing all commands in User Customization Auto-Completion manually?
Comment: Just to get this straight: Do you want to auto-complete *commands* such as `\cite` and `\autocite`, or do you want to auto-complete `.bib` entries such that if you cite `\cite{si` a list pops up where you can select `sigfridsson`?
Comment: Thank you @moewe I realized that the other question was on auto-complete of the bib-entries. Mine is on the commands.
Answer: If you want TeXmaker to autocomplete commands that it does not already know, you need to add these commands manually via User > Customize Completion", see How can I make texmaker autocomplete commands that it doesn't already autocomplete?. To add \autocite for example you could add
\autocite{#bib#}

in that dialogue window.
TeXmaker also automatically adds all .bib entries it can find to the autocomplete list (note that not all .bib files are found automatically, if they reside in a different folder from your .tex file, you may have to tell TeXmaker about that even though BibTeX/Biber can find the .bib file just fine).

TeXstudio (a fork of TeXmaker if I understand correctly) seems to have slightly more sophisticated autocomplete feature. It can automatically detect which set of auto-complete commands to provide. The biblatex autocomplete list seems very comprehensive and already has all the common commands available.
Comment: Yes, I already know how to use auto-complete by entering all these commands in the User Customize Completion. My question was if there is a way to get all the Biblatex commands into auto-completion without typing them on my own. Furthermore, what bothers me is, that when you have the auto-complete instead of showing the first command with a placeholder it suggests the first, second, third entry and so on and the command with the placeholder at last. Is there a way to change this? Also auto-completion does not work if you for example enter additional arguments like \autocite[cf.][@]{#bib#}.
Comment: @D.P. No, as far as I am aware there is no way to tweak the auto-complete in TeXmaker further, see https://tex.stackexchange.com/q/123481/35864. If you are not dead-set on TeXmaker and want a similar editor with better auto-complete you can try TeXstudio. Or you can ask the TeXmaker developers to include new features for the autocomplete. BTW: `\autocite[cf.][@]{#bib#}` worked just fine for me.
Comment: I guess I will switch to Vim. Everytime I create elements like box brackets before the curly brackets, as in `\autocite[cf.][@]{#bib#}`, it does not suggest to me the entries anymore.
Comment: @D.P. Mhhh, as I say, this works for me. Surely this is a bug you should report to the developers if you have made sure that it also happens in the latest release version and is consistently reproducible. You don't need to make the radical step to move to vim, you could also try TeXstudio (a fork of TeXmaker with enhanced autocomplete - amongst others),


Floor function not working

Question: Given the following cod:
<code> $number = 1050.55;
 var_dump($number - floor($number));
</code>
Why does the above code returns the following result?
<code>float(0.54999999999995)
</code>
I want a fixed value like 0.55 in this case. Can you help me please?
Comment: Floating-point arithmetic isn't always precise. So many duplicates...
Comment: Are you just looking for the remainder?
Answer: Floating point operations are not precise and the remainder errors are common.
If you know, what is your desired precission (eg. two digits after the dot), you can use round() function on the result.
In this case this will be:
<code>$number = 1050.55;
var_dump(round($number - floor($number), 2));
</code>
Answer: For most floats, binary can only approximately represent the correct number.  The rule is to perform floor(), ceil() or fmod() last in a series of calculations.  At least only do integer math after you use them.  If you cast an int to a float, as in your code,  then floor() is not going to behave has you expect.
Use printf() when printing floats.  Its conversion routines usually do a much better job and give you the answer you expect when truncating floats.
EDIT: Or, to be more exact, printf() works on the decimal character representation of the number when deciding where to truncate so you don't get any weird, unspecified, binary/decimal conversion artifacts.
Answer: See this question. While that is about java and you're asking about PHP the math is the same.

Floor function not working


How does Chakotay get his medicine bag back in "Initiations"?

Question: How does Chakotay get his medicine bag back in "Initiations" (season 2, episode 2)?  He had it in the shuttle that was destroyed.
Comment: https://www.youtube.com/watch?v=2ui85HwTX1s
Answer: At 22:32 you see Torres receiving various samples from the "debris field" of the destroyed shuttle. Although we don't explicitly see the bundle being recovered we do know that Voyager is very keen to avoid their technology falling into the hands of the Kazon and would have transported every part of the debris back on board.
Since we see the bundle again a few scenes later (apparently unscathed) there's no special reason to assume that it wasn't simply found floating in space with the other remnants of his ship.
From an out-of-universe perspective, the show's Prop Master seems to have reused the same leather chamois to cover the medicine bundle in both scenes. As you can see from the picture below, there are several heavy folds that are in the same place on each of the bundles. If it was replicated, then it was a masterful copy.
Answer: Chakotay kamikaze'd his Maquis ship into a Kazan dreadnought during the first episode of Voyager, being  beamed away only at the last moment.  As in the season 2 episode where he lost his shuttlecraft, he didn't have time to gather personal effects before he left.  So this was at least the second time Chakotay had lost his kit.  So he could only have assembled a new medicine bundle after each loss, either from replicated items or things he found on away missions in the Delta quadrant.


Will charcoal briquettes (not activated) absorb water out of the air in the house in a subtropical climate?

Question: I live in Florida, an incredibly wet environment where it's very difficult to get moisture out of house without using a dehumidifier 24/7, which is too expensive.  Would charcoal briquettes be of any use?
Comment: No, and even if the briquettes were able to absorb water, they'd be saturated in a day, and then you'd have to dry them or replace them, far more expensive than A/C.
Comment: I know this wasn't your question, but it might be helpful: Dehumidifiers differ in their energy efficiencies.  You might want to make sure yours is on the high side (you could check the Energy  Star rating; you can also check Consumer Reports if you have a subscription).   And you probably already know this, but there are several things you can do to optimize your dehumidifier's efficiency (keeping it away from walls to ensure maximum airflow, keeping the filter clean, etc. -- you can search for more detailed info. online if you're interested).
Answer: The body of your question shows that your primary concern isn't charcoal's hygroscopic character per se but it's suitability as a practical means to lower the relative humidity inside your house.
Let's start with it's hygroscopic character: It seems that charcoal indeed displays hygroscopic properties (the propensity to absorb water to itself) to some degree (at least to the extent that it affects it's burning properties).
The subject was treated by this paper, wherefrom the following citation was selected as part of this answer to your question:

The charcoal samples placed in the environment with high relative humidity showed an
  increase in humidity by the heightened final carbonisation temperature, with the highest average detected for charcoal produced
  at 750 °C. This was the reason why the charcoal produced in
  this temperature showed higher moisture related to higher porosity
  presenting a larger area available for water condensation inside the
  pores.
The difference between the moisture adsorbed by the charcoal packed in
  two environments can be attributed to more water molecules present in
  the humid atmosphere (RH = 98%) and a greater ease of inducing the
  porous region of the charcoal. This means that the more humid the
  environment, the greater the adsorption of moisture by charcoal.
These two different moisture conditions represent different possible
  situations of charcoal storage where high relative humidity is not
  ideal.

Now if one of the reasons you would like to use charcoal over other means of lowering the humidity inside your house is that you were planning to re-use the charcoal later for it's primary purpose (as a fuel), this means that it wouldn't suit that purpose very well, at least if you don't plan to dry your charcoal as an intermediary step in the process (dehumidify > dry > burn). Water requires a lot of energy to evaporate which would waste fuel if you wanted to use it directly as such after using it for your house.
Now for absorbing humidity, there are other (much better) substances you could use out there: You could for instance use the very safe and well known SiO2 form frequently referred to as "silica-gel", which works very well at higher RH levels, and can be conveniently "recycled" by ~ 1h pass in the oven at ~100-120C. The main weakness of silica gel in your case is that it quickly loses efficiency at higher temperatures that are not uncommon in Florida. If you'd like to be a slightly less conventional, one could recommend Calcium Chloride (CaCl2), a fairly cheap substance which will hold up to ~4 molecules of water for each of it's own up to a temperature of 45°C, and at the very minimum 2 molecules of water for each of it's own at any temperature naturally encountered in Florida.
I hope this helps!
Comment: Desiccants are not practical for whole house dehumidification.
Comment: A couple of comments: it's $\ce{CaCl2}$, and the mole ratio looks much less attractive when translated into a weight ratio.
Comment: Desiccants need to be cycled, which I agree can be impractical, but I firmly believe that CaCl would be more practical than coal. Without using desiccants, condensating the water would be the only practical option.
Comment: Here's an application that will dehumidify your home and provide running water: https://www.nature.com/articles/s42004-018-0028-9 :-)
Comment: @BuckThorn That is correct, not sure why I wrote it wrong (twice!)
Comment: Yes, CaCl2 is in fact employed in commercial moisture removal products (example, DampRid). Reheating the hydrate to re-use may be somewhat successful. However, my experience is that once you expose fresh CaCl2 to air/CO2, with time it appears to create, to a limited extent, an insoluble basic hydroxide or mixed carbonate salt therefrom, which limits its usability.


Remove asbestos-covered ductwork or leave in place?

Question: Asbestos tape-covered ductwork that is coming from the furnace leading to each vent in the entire house. Is it a bad idea to leave it as is without disturbing, or would replacing all hvac system coming from the furnace be a better solution?
Answer: Asbestos is OK as long as it doesn't get airborne. No reason to disturb it unless you're going to be renovating that area (and even then you may be best off leaving it).
Answer: I agree with some of the information in the post @isherwood linked. In my state as long as it is double bagged any home owner can remove any and all the waste no limit on the amount that goes to the landfill. I would recommend a high end respirator cartridge type if the job takes multiple days you should use a fresh cartridge each day disposing the old one when finishing for the day. Also a   tyvek suit, gloves and boots taped at wrists and ankles. Then a small garden sprayer with water to wet the material down before it is removed and bagged the water spray further reduces the dust. This is how the professionals do it I have worked with them on a large abatement project when retrofitting a mill I worked in. I would take the precautions listed above and not have anyone in the house while the work is being done until a wipe down of the surfaces are completed.


HTTP-header canonical and link tag canonical on same page?

Question: I've come across websites using both a HTTP-header based canonical as well as a tag-based canonical. Sometimes they are not referencing the same URL which brings me to my question - does one have priority over the other and is there a SEO related penalty to using both on same the same page?
Answer: Since Googlers mention this issue on one of their blog post:

Specify no more than one rel=canonical for a page. When more than one
  is specified, all rel=canonicals will be ignored.

5 common mistakes with rel=canonical
Google algorithm can can ignore both of them if they point to different urls
Comment: Thanks! I wonder if this is also true for a header based canonical combined with a tag based one.
Answer: If they do not link to the same there will be trouble for the good old g-bot. He does not know what to do then with those pages. The outcome will be less or wrong indexed pages. Which will lead to loss of rankings.
Normally such stuff will be shown in the search console messages if something like this is happening.
Same with hreflang - different/wrong setup = google bot gets confused and does "stupid stuff".


QGIS - Change Coordinates from decimal degree to UTM/Gauß-Krüger

Question: Is there a way to change the coordinates of a shapefile (points) from lat/long to UTM or Gauß-Krüger within the same CRS (i.e. WGS84:4326)?
Answer: In general, you can reproject any shapefile to your desired CRS/Projection by just saving a new copy of it with that CRS applied (layer -> right click -> save as... and set desired CRS in dialog).
But what do you mean by 'within the same CRS'? UTM projection uses WGS84 or GRS80 as reference elipsoid, Gauss-Krüger however is projected and bound on/to either the Bessel or Krassowski elipsoid. You can reproject your lat/long to both, but for Gauss-Krüger you cannot (and don´t need to) keep the WGS84 reference system.
Comment: Just for completeness, you can have decimal degrees based on Bessel and Krasowski ellipsoid as well, choose EPSG:4314 (DHDN) or EPSG:4383 (Pulkovo) as target CRS.


Is it possible to use a M/S microphone as a mono mic?

Question: Is it a normal mono sound you get if you use a M/S stereo mic by only plugging in the left or center? Does it sound like a normal mono shotgun mic?
Answer: SOME M/S microphones provide discrete access to the Mid and Side outputs, but most provide only the matrixed Left and Right derived signal outputs.
Your question cannot be definitively answered as a generic question.  It depends on exactly WHICH M/S mic you are talking about and whether it provides Mid and Side outputs?
Specifically, the Sennheiser MKH 418S has separate line-gradient ("shotgun") MID microphone and a separate figure-8 "side" microphone. It seems quite reasonable to expect that the "MID" shotgun section can be used independently without powering the "side" microphone section.
Ref: http://www.bhphotovideo.com/c/product/283358-REG/Sennheiser_MKH418S_MKH418S_Stereo_Shotgun.html
Comment: I will be using Sennheiser MKH 418S, from where I get 2 mono xlr inputs. Is it possible to record mono if only plugin the center? Does it sound like a normal mono shotgun mic?
Comment: Answer edited to address specific microphone make/model.
Comment: Even if an M/S microphone outputs the signals matrixed to L/R, the mono signal you get by mixing these signals in phase (which basically inverts the matrix) should still be very good – much better than the mono mix from other stereo setups.
Answer: Yep you certainly can just use the centre on a 418! Its similar to a 416 if you so this.
Answer: Yes. Absolutely. Mono-Compatibility is exactly what Mid/Side recording is designed to accomplish, in fact quite a lot of Mid/Side recording rigs actually consist of a standard mono shotgun condensor mic with a figure-8 microphone gaffered to the top. Works extremely well. Of course you could go for a 418s - type solution where you have a shotgun mono Mid mic integrated with a figure-8 side mic in the same tube, or you can go for the redneck repairs style of solution. Both work equally well.


Do roles have an owner in oracle?

Question: Suppose that I have logged in to oracle database using user X, then user X creates some roles using create role command. I want to know that is user X the owner of the roles? Can I select all roles created by user X?
Answer: The roles in Oracle Database have no owner as well as directories have no owner.
When the user with CREATE ROLE or SYSDBAprivilege creates the role, he or she is automatically assigned that role WITH ADMIN OPTION which means that the user can subsequently grant that role to other users even if the privilege CREATE ROLE is revoked from the user.
You can see what roles are assigned to which users querying DBA_ROLE_PRIVS view, or USER_ROLE_PRIVS if you want to know what roles are assigned to the current user.
Also, a user cannot create a role  if the role with the same name already exists. However you can audit role creation and granting. You can do that with AUDIT ROLE statement (if it was for some reason disabled with NOAUDIT ROLE), and then querying DBA_AUDIT_TRAIL view.
Answer: Although a role does not have an owner, dba_role_privs shows both users and roles granted to a privilege.
--This lists both users and roles
SELECT * FROM dba_role_privs
WHERE admin_option = 'YES'
order by grantee, granted_role;

Inner Join to dba_users to see only users with admin option on roles.
--This lists only users with admin option on roles
SELECT rp.grantee, rp.granted_role, rp.admin_option
FROM dba_role_privs rp
JOIN dba_users u
  ON rp.grantee = u.username
WHERE admin_option = 'YES'
ORDER BY grantee, granted_role;

Answer: If you have the admin option over a role you can drop that role, even if you don't possess the drop role privilege or "own" the role, as in, you didn't create the role.

Do roles have an owner in oracle?


Black Holes emitting Hawking radiation

Question: I've read that even light cannot escape from black holes.
The speed of light is theoretically predicted to be the escape velocity of a black hole.
I've also read that the general notion that nothing can escape from a black hole is wrong.  Even black holes emit particles and radiation known as the Hawking radiation.
My question is: How can black holes emit any kind of radiation?
If they even do emit, wouldn't the speed of the radiation be less than or equal to velocity of light?
If the escape velocity of a black hole is c, then how can the Hawking radiation even escape the black hole? Wouldn't it be pulled back into the black hole? Then, how is it even
emitting anything?
Comment: Hawking radiation is emitted from the general vicinity of the black hole, it doesn't have to escape the event horizon.
Answer: The escape velocity is c at the event horizon of a black hole. Above the event horizon the escape velocity is below c. Escaping particles of the Hawking radiation form above the event horizon; that's why they can escape, if they are pointing towards a sufficiently narrow angle to vertical upward, and if they are sufficiently energetic.
Escaping particles form as virtual particle-antiparticle pairs in the "infalling" coordinate system: One of the two particles forms outside the event horizon; the counterpart forms below the event horizon. Thus the originally virtual particles cannot annihilate, and therefore become real particles; one particle can escape; the counterpart falls toward the singularity.
The energy needed to form the escaping particle, and its remaining kinetic energy after escape, is subtracted from the mass of the black hole.
The described mechanism probably works also for both particles forming very close above the event horizon if the tidal forces are high enough to separate the virtual particle pair, before it can annihilate.
Formation of virtual particles is due to the Heisenberg uncertainty applied to time and energy: Very short time intervals require energy uncertainty, leading to short-lived particle-antiparticle pairs.
Comment: But, when the Hawking radiation is on the inside, everything else coming form inside, how can a particle, even if it is virtual, form on the outside? Also, how exactly are they 'virtual'?
Comment: Virtual particles form spontaneously and usually live for a very short time, less than about 1e-22 seconds, details see http://en.wikipedia.org/wiki/Virtual_particle. Only half of the radiation is in the inside, the outside (anti-)particle can become Hawking radiation. A particle looking virtual from an infalling coordiante system can look real from outside, because of extreme time dilation near the event horizon.
Answer: The real explanation for Hawking Radiation does not concern virtual particles. My simplified version of the real explanation is that curved space-time has a different minimum energy amount for a moving object than normal "flat" space. Therefore, energy flows outward from the warped area.
Because of this explanation, it has been determined that smaller black holes evaporate faster because they curve space more than the larger ones.
Personally, I do not believe in virtual particles, simply because you can't get something from nothing.
Comment: The virtual particle explanation of Hawking radiation is a simplified "cartoon", it shouldn't be taken too literally. Your answer is better, but please see https://physics.stackexchange.com/a/252236/123208 Virtual particles are a useful mathematical device, but they don't have the same physical status as real particles. You may enjoy https://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/
Comment: I'm sure there is a great answer here, but the phrasing and detail could be improved.  Can you give some details on how "curved spacetime has a different minimum energy for a moving object than flat spacetime." What is the moving object here? The black hole? but HR doesn't require the BH to move (relative to what?)  Is HR predicted around other massive objects, or is the event horizon significant in some way. If it is just "energy flowing out of curved spacetime" then surely everything with mass would produce HR. Saying "I don't believe" greatly weakens the answer, belief doesn't count.

Black Holes emitting Hawking radiation


Negative gate pulse to a thyristor

Question: If a positive gate pulse is given to a forward biased thyristor, it gets turned on. What will happen when a negative gate pulse is given to a reverse biased thyristor ?
Answer: Nothing... Well unless it is really really high and you get GTO like  behaviour ( although the magnitude and di/dt needed to force the abnormal affect is very unlikely)
Comment: Could you please explain the reason.
Comment: If the negative gatepulse is high enough it essentially removes the minority carriers from the base area of the NPN stack. This current however is higher than the fwd current and more of a physical phenomenon not something likely to occurred.
Answer: In normal operation of a Thyristor or SCR, nothing.
Excess voltages of dV/dt spike will eventually cause some kind of transient or permanent breakdown.  Excess is a relative term and such operation is usually not desirable.
Triacs have conduction modes in the other quadrants.
Also see this similar question.

Negative gate pulse to a thyristor


How do you write a story with someone else overseas?

Question: My friend and I have wanted to write a story together for a while now. But she lives in a different country, so we are just confused on how we can do this over calls. Because I know that we can't call all the time, like we can't just take turns writing and then editing each others work because it would just be confusing. So does anybody have any advice on writing with someone else when you aren't together? Any advice would be greatly appreciated.
Thanks :)
Comment: Collaborative editing software like Google Docs is great for this, it lets you edit the same document over WiFi and shows revisions and history :)
Answer: This is a great question! Here are some helpful resources I found when I had this same problem.
Google Docs
Google Docs is an excellent free collaborative document editing program that lets you edit a document with someone over WiFi. You can see them editing in real time, and it provides revision and editing history so you can go back in case somebody makes a mistake.
All you need to do is make sure both of you have a Google account, create a new document, and give the person you're writing with editing permissions.
Notable features:

Completely free

Requires a Google account to use (but that's it!)

15 GB of storage (you can buy more though)

Microsoft Office Online
This is basically Microsoft Word, but expanded so that you can edit in real time with a friend. It does require you to have access to an Office subscription to access it, so it's not free. However, it's a great alternative to Docs and has many more features, since it's a paid service. (It also lets you make collaborative PowerPoints and Excel sheets, which might be useful to you for story planning.)
Notable features:

Requires an Office subscription (i.e. Office 365 or Student Office)

Tons of features when compared to Docs

Unlimited storage (provided it can fit on your hard drive)

Zoho Docs
I've never personally used this one, so I can't attest to it myself, but Zoho Docs purports to be a productivity app that offers real-time document editing. The user interface is very different from Docs and Word, so it takes some getting used to, and the free version is very good for what it is - you get 5GB of storage and a file upload limit of 1GB.
Notable features:

Free (trial version)

5GB of storage in the free version (file upload limit of 1GB)
Answer: I use Joplin. The free version allows syncronization on two devices.
What I like best about it is that you can organize better than other tools the structure of your work over multiple documents.
You have different 'notes' (each could be just a simple note or a full blown chapter, there are no real limits in legth).
You would both use Markdown conventions (just like Stack Exchange) so editing is fast (once you learn) and your style will stay consistent. It's also easy to insert links to other notes or 'anchors' (a particular position within a note e.g. a word definition on a dictionary page).
You can setup the text editor you prefer and see the preview in real time.
It has limits when it comes to layout of the page, tracking changes (which user did what) and of course number of devices (two can be a bit tight considering you may want to edit both from your cellphone and your PC, same for your friend).
Anyway it's worth checking out. May suit your project.
P.S. I read that they are working on tracking user changes but have not really explored it more as for the moment am not using that feature.


My split A/C unit doesn't drain much water

Question: My split A/C unit used to drain much water when it was new. Now, the unit drains much less water than before. I checked the drain line and it isn't clogged. Also, the cooling efficiency is slightly lower than before.
Answer: You need to find out why the cooling efficiency is slightly lower. Offhand, I'd guess it's a clogged filter.
If it's low on gas, it will freeze up the coil and produce less water (and not work very well), but a whole bunch should come out when it shuts off and melts This should happen within a few minutes, so don't walk away, while you:
Let it run for a good while, and then set the fan to on and the A/C to off; what happens? If lots of water starts coming out, you're low on gas and your coil is freezing up.
You can confirm this by removing the panel from the coil, and you'll see it's all froze up. Seeing frost on the 'fat' line (at just outside of where it enters the coil) is a good indicator, too.
Answer: I agree with @Maura but low air flow from plugged filters or a dirty coil can cause the same thing. Yesterday I replaced a small unit that was not cooling at work, the filter was clean. I decided to remove the covers and found the evaporator coil to be totally plugged (inside coil) cleaned it with coil cleaner and is is now fully functional. The outside condenser coil if dirty will also reduce how much heat the unit can exchange if it is plugged with dust it may not be able to remove enough heat. A simple garden hose used to flush the outside may also get you back to like new.
Comment: The heat exchanger inside the furnace could be clogged too which will reduce airflow.


Good conferences on (computational) neuroscience in Europe and whether to submit to conference or journal?

Question: I'm looking for good (computational) neuroscience conferences in Europe that $\textbf{have proceedings}$. Recommendations? Or are there even such conferences? Should I just send my work to a journal? I'm new in neuroscience, and it seems (compared to CS/Physics) that conferences are not so respected in this field.
Comment: The Bernstein Conference in Germany is nice: http://www.bernstein-conference.de/. Concerning publications: I might be wrong, but I do not think that conference proceedings are that much valued in neuroscience. The standard way is to publish in peer reviewed journals.
Answer: To touch on your broader question, as I understand getting full text publications in conferences are highly respected in computer science. In psychology and neuroscience (note I don't know so much about computational neuroscience), publishing papers in high impact journals is more respected in the field. While some conferences do have full-length papers, such publications often carry little weight. It is often tricky to even hunt down such conference proceedings. As such they are often barely part of the published research literature.  So yes, in psychology and neuroscience, you should generally submit your work to journals if you want to maximise its scientific impact.
That said, conferences are important in psychology and the neurosciences. As with any field, conferences are an important opportunity to network, share ideas, form collaborations, learn about developments and so on. A very common strategy is to present a work in progress at a conference. This allows you to set a preliminary deadline, get some feedback, and then refine your ideas before submitting to a journal.
Answer: I do not know of any computational neuroscience conference with proceedings that is always held in Europe.

Neural information processing systems (NIPS) was held in Europe only once recently, but back in US. (it was in Spain on 2011)
International joint conference on neural networks (IJCNN) has minor section on computational neuroscience but it's mostly held in the states.
International conference in acoustics, speech and signal Processing  (ICASSP) sometimes has computational neuroscience related topics, but it's very very minor. It'll be in Italy next year.
European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning (ESANN) seems to have proceedings, but I'm not sure. I have never been to one.

Bernstein Conference and CNS are good conferences but they don't have proceedings, I believe.


When would the next glaciation appear? Worst case

Question: Suppose that the IPCC's best estimate of climate sensitivity (3 K) is relevant and that the Keeling curve will increase as now, with a certain procent more emission next year than previous year, into year 2100, when would the average temperature earliest become low enought for a new period of glaciation, due to the Milankovitch cycles?
Comment: That contradicts a common cc deniers argue (that we need to warm the atmosphere to evitate a glaciation). In 50.000 years the technology for sure will modelate climate with a better understanding of Earth System. We are just worsing things causing human and economic losts due to extreme events needlessly. That is observed with an increase of 1.1ºC and quantified by IPCC. Nobody knows well the consequences of an increase of 3 or 4ºC.
Comment: I asked a similar question and David Hammen says [in 50.000 years](https://earthscience.stackexchange.com/a/21053/20559)
Comment: What do you mean by "worse case"? Which is worse, hundreds of years from now (not likely), many tens of thousands of years from now, or never?
Comment: @DavidHammen - I mean how long the pause will be because of AGW now and in the future.
Answer: Milankovich cycles are steady predictors, so sometime in the next 24-50 thousand years. But "Glaciation" is a broad terms, glaciers take long time to accumulate, but they accumulate, EVEN NOW. 100 years is simply too short a time frame to judge circumstances for long term climate trends. We just emerged from the little ice age, during which there were glaciers, that receded by the 1880's
Comment: Would the atmospheric carbon dioxide of today move to the lithosphere in that time scale?
Comment: We emitted a few million years worth of buried CO2 back into the atmosphere. MOST of the planets CO2 was not absorbed by photosynthesis but by geologic progeny (rocks) as Carbonates, that process has slowed alot since then. Returning atmospheric conditions back to pre-industrial levels, not that I would support it (285 ppm) would take well over 1000 years or more.


What are the reasons for ADSL to use ATM instead of Ethernet

Question: I'm a newbie to networking and I wonder what are the reasons for ADSL to use ATM instead of Ethernet ?
Comment: Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
Answer: According to the German Wikipedia the bit rates used in the time when ADSL was invented was the reason:
At that time the backbones of the telephone and internet providers operated at 1-40 MBit/s while today rates above 10 GBit/s are used.
At 2 MBit/s a packet of 1000 bytes length would take 4ms time for transmission; at 1 MBit/s a packet of 1500 bytes would take 12ms.
Because the optical fiber is blocked during this time no other data or voice can be transmitted for this time.
For voice telephony this means that voice will be delayed up to 12ms which seems to be too long for voice telephony.
Therefore shorter "packets" had to be used to ensure that voice packets are not delayed too much. ATM uses 53 bytes.
EDIT

But, it doesn't exactly explain why ADSL ... uses ATM.

It would of course be possible to send Ethernet frames via ADSL and to split these frames into ATM cells at the provider's "router" (I don't know if "router" is the correct word here).
However this would make the provider's router more complicated: If ATM is already used at the customer's home the router simply has to route cells; it does not have to convert Ethernet to ATM and vice versa.
ADSL uses ATM to transport PPP frames which carry IP packets. You could ask why ADSL does not use ATM to transport Ethernet frames instead of PPP frames.
However before ADSL was introduced analogue modems were used. Analogue modems use PPP frames, not Ethernet frames.
So PPP was the de-facto standard data format for transferring data between the customer and the internet while Ethernet was rarely used; most PCs did not even have a network card in the 1990s!
Changing the protocol later on would mean: Develop new devices and throw away the old ones. Therefore this change was not made.
Comment: This is, indeed, why ATM exists (and yes, 53byte cells were a level-the-playing-field compromise to make everyone build new hardware, vs. giving those that had already made 32/64b hardware a leg up.) But, it doesn't exactly explain why ADSL (which was exclusively data in the beginning) uses ATM. There are systems that use frame-relay, btw. (and AT&T Uverse's redheaded stepchild ADSL/PTM that nothing else does -- that's ethernet, btw)
Comment: English wikipedia also describes the 48-byte payload as a political compromise between 32- and 64-byte, proposed by different groups, and describes 5-byte header as what was considered reasonable.
Comment: @RickyBeam I updated my answer
Comment: (more history) PPPoEoA, so ethernet was in there. PPP was there because it grew out of dialup and was an existing means of authentication.
Answer: When ADSL came up in the late 1990s, Carrier Ethernet was in the far future - Ethernet was just 100 Mbit/s back then.
Then, carrier networks were SDH and used ATM as base protocol. This has changed significantly since, with Ethernet being far cheaper, more efficient, flexible and easier to scale.


Can ♦ moderators see our real name or e-mail?

Question: Just as the question stated. I know it is marked under the private section of our profile, but I was just wondering if you could see stuff like that. And if you don't, do you see anything else that a normal/regular user wouldn't see?
Comment: One other point worth making is that a lot of people who "moderate" (eg edit, review, nominate to close/reopen, etc) aren't actual "moderators" but regular users with a high enough reputation level.  These people can *not* see private information in profiles.  I just wanted to make the distinction, because you may think of all these people as if they are "moderators" when only those with the ♦ next to their names are official moderators.
Comment: Same answer != duplicate. I don't even think that other post answer the question anyway. Reopening.
Comment: real name != name you provide :-)
Comment: @neon_overload I edited the title.
Answer: Yes, moderators can see your real name and email, although this information isn't something we see on your profile by default, we have to click several buttons to see it. We also have to agree to abide by the Stack Exchange Moderator Agreement when we become moderators. This states:

ii. I acknowledge that I may have access to potentially
  personally-identifying information about Ask Ubuntu users and that in
  connection with such access
a. I will use such information solely in accordance with the then-current Privacy Policy of Ask Ubuntu,
b. I will not disclose this information to anyone,
c. I will not store or copy this information and
d. I will only use such information in connection with performance as a Ask Ubuntu moderator for the benefit of Ask Ubuntu.

So you can be sure that your information is pretty safe.
As to your question about other things we can see, moderators have access to all privileges as well as various other tools used in the moderation of the site. If you have any more specific questions ask away.
Comment: Additionally, the viewing of personal data is itself logged to the system. This provides some level of deterrent against abuse.
Comment: @KasiyA to tell you an example, when you fill a bank form they said that the information is private but they can access it and many of them have a closure of what they can do or not with the data that you must accept. This is why when working with services you normally sign an agreement of privacy. In askubuntu you have "By registering, you agree to the [privacy policy](http://stackexchange.com/legal/privacy-policy) and [terms of service](http://stackexchange.com/legal/terms-of-service)." when registering.
Comment: @KasiyA Private means private to only special people or not visible to all public. And this is the normal meaning of private in **all** sites. If no one can see it then it isn't useful.
Comment: I don't really understand what you are upset about @KasiyA, do you think we are going to spam your email or something?
Comment: This is the reason I don't fill out these fields and use a bogus email.
Comment: @don.joey that is the reason why the do not necessarily have your *real* name ;)
Comment: Byt why the labeled as "Private"??? then according to your answer they are not private OR perhaps I don't know real mean of the "Private". why??? or it will better if re-label to "share with Moderator". I really unlike this >:o, why site didn't tell that the moderator can see my Private Email ??? Also in Email text box titled "never displayed,..". at least you could replace it "show only for moderator..."
Comment: @PhoneixS :D :D Then public means public to all private or not visible to only special people, right?? :D . **MAN** this is not my answer and I'm not at all happy about this.
Comment: I'm not upset, I I just furious, but not about you and other moderators, about the "Private" label. they could labeled it as not private then I was not upset about that, so it's labeled "Private" while @PhoneixS [in his comment](http://meta.askubuntu.com/questions/12006/can-%E2%99%A6-moderators-see-our-real-name-or-e-mail#comment21031_12007) says me "it means private to only special people". Then why the SITE not told me it means "private to only special people" if that is true. sorry for down vote,sorry


Which Eclipse distribution is good for web development using Python, PHP, or Perl?

Question: I'd like to try out Eclipse, but I'm a bit baffled with all the different distributions of it. I mainly program in Python doing web development, but I also need to maintain PHP and Perl apps. It looks like EasyEclipse is a bit behind. Should I just grab the base Eclipse and start loading plug-ins?
Answer: Maybe try Aptana (http://www.aptana.com/) - you can then plug in as many extra modules as you require.
Answer: PDT 2.0 is vey good Eclipse PHP Ide . It is created with cooperation with Zend, so there a lot of featuers from Zend Studio.
I also use it with Subeclipse(for SVN) and Target Management (for work on FTP remotely).
I will also advice to use Aptana plugins fot HTML and Js - they are much better than standard Web Tools from Eclipse.
Answer: I develop Python applications at work and find Eclipse Classic and Eclipse for Java Devs a good fit because I don't do any plugin or Java EE Stuff. We use Eclipse for Java, Python, and NSIS (nullsoft installer) scripting.
The Python development I do requires the pydev plugin (see: http://pydev.sourceforge.net/) which so far has been fantastic on a Windows machine. I found some instability on a Fedora 9 machine, but that is not the general consensus among my linuxier colleagues :)
The pydev plugin comes with a very minimal set of customizable features including a short list of syntax for colouring, and it's very easy to create a dark colour scheme (black bg, bright text) for python development (if that matters to you). The debugger has been pretty good so far, but I have problems when my applications hit threading in PyQt. I don't know if that is a problem with QThread (a Qt Thread) or python threads in general.
I can't offer any advice regarding PERL or PHP but basically like you said, download an Eclipse version and find some good plugins for your development environment.
Answer: PyDev is pretty decent as I'm sure you know. It can fit on top of all the Eclipse distributions (provided they meet the minimum version requirements). If you're doing webdev stuff, you'll probably find the closest fit with Aptana.
That said, I find Aptana hideously clunky when compared to a decent text editor. I build sites using django and for that I use Eclipse (pure) and PyDev to do the python and gedit (gnome's souped up notepad) for writing the HTML for templates/CSS/JS/etc.
At the end of the day, whatever suits you best is what you'll go with.
Answer: EPIC is the only Eclipse Perl plugin I know for Perl.
The integration is okay. Offers a graphical debugger, but watch out for inspecting data that contains cycles, as the perl exec could just go into an infinite loop
Answer: I develop in PHP, python, C(python modules), SQL and JS/HTML/CSS all on eclipse. I do this
by installing PDT, CDT, pydev and SQL tools onto the eclipse-platform, and then using different workspaces for mixed projects.
Two workspaces to be specific, one for PHP web development and another for Python/C. I do run it on a rather powerful machine so I allow eclipse the luxury of added memory (2G).
Works like a charm and it is very nice to be able to use the same IDE for everything :)
Answer: I use the javascript eclipse helios and added pydev plugin to it for django support it seems to do everything I need.


How do I change a username? (shortname and home folder)

Question: Under Linux, this would be a no brainer. Just go into /etc/password and edit that, and rename the directory in /home.
I want the new shortname and the new home folder to match after the change.
Comment: Just a side note: in Linux it not so straightforward. You also have to update `/etc/group`, eventual mail alias (e.g., username@machine)  and all the places where your old username is present (usually many).
Answer: Apple's own instructions work quite well. There may be more complex and faster ways out there, but I've never run into an issue (such as incorrect permissions) with these steps.
Mac OS X v10.6 and earlier: How to change user account name or home directory name
Comment: This is certainly the "official" way to go - but it has two drawbacks: The big one, is you end up with a different UID. It's not a big deal, but for most people, keeping user number 501 is the least hassle when connecting an external drive to another mac. The other is it's longer than needed. I presume Apple decided to have a much longer process to avoid telling someone to delete a user account since some people will not read things and end up deleting everything - potentially without a backup.
Comment: I did not realize the bit about the UID - haven't run into a problem regarding the UID, but it's certainly something to consider.
Comment: This worked fine for me, thanks. I thought it would be harder.
Answer: In System Preferences, Users & Groups, right click the username in the list on the left and select Advanced Options. Edit the Account name field and click Ok.
Ideally you'll also want to edit the Home directory to match the new username, although this isn't strictly necessary.
Comment: Ingmar Hupp is referring to the dialog box that appears when you select "Advanced Options."
Comment: How do we change the home directory to match the username? Renaming it in finder doesn't seem to work
Answer: I really don't like to edit a user in place since it's so simple to delete the user (preserving the home folder) - rename the folder as root - make the new user with the correct short name matching the renamed folder.
The preference pane will see that you already have /Users/newshort and offer to inherit the folder. It does the best job I know of in setting ownership and correcting the ACL needed for your home folder to work as Apple intended.

Check your backup is current - just in case
Do the delete

Do the move in terminal sudo -s followed by mv /Users/tester\ \(Deleted\)/ /Users/test
Do the create
Comment: Repair Permissions never touches a user home folder. It only fixes software that Apple has installed by looking at /Library/Receipts (or the newer receipts database) - the user permissions are only set by the preference pane / dscl / open directory that's new in Lion.
Comment: You should *probably* run the "Repair Permissions" task in Disk Utility after performing this action. Since the Unix user ID will be different after deleting and creating a new user.


This SR latch built with 180nm CMOS does not work in ltspice. How do I fix its behavior and parameters?

Question: EDIT: I copied over the latch from another larger model that had Vdd defined, but missed it when copying over the design. However, after adding in Vdd, I still run into this confusing issue where the R seems to trigger Q and not S.
I used these 180nm mosfets to build this SR latch:

I used the nmos4 and pmos4 and added a spice directive with the models. I sized the nmos as L = .18um and W = .5u and the PMOS as L= .18u and W=1u (to get more symmetrical rise fall time, though Im not sure by what factor exactly I would need to scale the width):

However, even though I followed a regular schematic for an SR latch it does not work. When the S and R are triggered it seems that R triggers Q and not S.  Then again, not all the parameters are recognized by ltspice and Im not sure how to get around that other than by using another transistor. Is there a way to make this current design work? Also, any chance someone could let me know if the warnings I am seeing are a clear need to fix a particular thing in the circuit?

[
Comment: Look at the top CMOS stack, when S=1, Q=0. Is that what you desire?
Answer: I don't see a power source providing Vdd in your schematic. How would you expect that to work?
The spikes you see are just capacitive coupling.
Also, you mislabeled your nodes. Q and Qb are reversed.
Comment: yes that is true. Thanks for pointing that out. I forgot to add in Vdd. It had been defined in the other segment of the circuit I did not include in this particular schematic


Getting Concurrent Session Metrics from IIS Raw Logs?

Question: I have IIS 6 and 7 raw log files and the Log Parser tool version 2.2 and I want to find the peak/max concurrent sessions per day that are recorded on the logs for the last 30 days. Is there a quick example of how to do this with Log Parser? Or is there a better alternative approach to create the report using a different tool?
Answer: Have a look here.


Can repunits be perfect cubes?

Question: Is it true that the equation $10^{n}-9m^{3}=1$ has only one positive integer solution, namely $n=m=1$? I can't find the answer. This has an equivalent description that the repunits $R_n = 11\dots1$ are not cubic numbers.
Comment: In case it is of interest, it is even known this cannot be a perfect power (not just not a cube), proved by Bugeaud and Mignotte in "Sur l'équation diophantienne $(x^n - 1)/(x-1)= y^q$, II" (see Thm 5).
Comment: @Barry: This elementary method doesn't work. In fact, it's not too hard to see that for every positive integer $d$, there exists an integer whose cube ends in at least $d$ digits $1$. (And this number is unique modulo $10^{d+1}$.)
Comment: @Tom (and Wangt Fei) sorry, you're absolutely right.  I made a very stupid mistake.  I somehow miscomputed $(10a+1)^3 \equiv30a^2 + 1$ instead of $30a+1$.
Comment: I think this question is better suited for math.stackexchange.  It looks like a straightforward exercise in elementary number theory.  (Hint:  Solve $b^3\equiv1\mod10$ for $b$ and then $(10a+b)^3\equiv11\mod100$ for $a$.)
Comment: I know that Rn≡n(mod 9), and if Rn is a cubic number then n≡0, ±1(mod 9). The left appears difficult.
Comment: Quid, in base 18 there is a cube: 324 + 18 + 1 = 343.  Gerhard "Ask Me About System Design" Paseman, 2013.05.27
Comment: @Gerhard Paseman: yes, but the $R_n$ in the question, to which my "this" refers, is *base ten*, else this would not be equivalent to the given equation.
Answer: Rather to my surprise I find an entirely elementary proof that
$R_1=1$ is the only (decimal) repunit cube, using nothing beyond
quadratic reciprocity (namely the formula for the Legendre symbol $(-5/p)$).
Let us first dispose of the case that $n$ is even, say $n=2k$.
This is routine: write the equation $10^n - 9m^3 = 1$ as
$$
9m^3 = 10^n - 1 = 10^{2k} - 1 = (10^k-1) (10^k+1).
$$
The two factors are relatively prime, and $10^k-1$ is a multiple of $9$.
Thus once $k>0$ it follows that $10^k-1 = 9m_1^3$ and $10^k+1 = m_2^3$
for some $m_1^{\phantom.},m_2^{\phantom.}$
with $m = m_1^{\phantom.} m_2^{\phantom.}$.
But then $m_2^3 \equiv 2 \bmod 9$, which is impossible.
(The solution $(m,n) = (0,0)$ escapes because in that one case
the factor $10^k-1$ is zero so there's no condition on $10^k+1$.
We could also have used descent, since $10^k-1 = 9m_1^3$
would be a smaller solution of the same Diophantine equation;
the solution $(m,n) = (0,0)$ escapes this argument because $k=0=n$
so the new solution is no smaller.)
The hard case is $n$ odd.  For $n=1$ we obtain the
known solution $(m,n)=(1,1)$; and there is no solution with $n=3$
because $R_3 = 111$ is not a cube.  We may thus suppose $n \geq 5$,
and write $n = 2k+3$ with $k$ a positive integer.  Now we take
the strange step [see comment at bottom] of
adding $9$ to both sides of the equation
$9m^3 = 10^n - 1$, and writing the result as
$$
9(m+1)(m^2-m+1) = 9m^3 + 9 = 10^n + 8 = 10^{2k+3} + 8
= 8 \left(125(10^k)^2 + 1 \right).
$$
Thus if $p$ is any odd prime factor of $m+1$ then $p \neq 5$ and
$25 \cdot 10^k$ is a square root of $-5 \bmod p$, so $(-5/p) = +1$
and by quadratic reciprocity $p$ is one of $1,3,7,9 \bmod 20$.
As usual, this set of residues $\bmod 20$ is closed under multiplication,
so we conclude that any odd factor of $m+1$, prime or not, is one of
$1,3,7,9 \bmod 20$.  In particular this is true of $(m+1)/2^f$,
where $2^f$ is the largest power of $2$ dividing $m+1$.
But since $n > 3$ (this is how the solution $(m,n)=(1,1)$ escapes
the coming contradiction) we have $f=3$ because $125(10^k)^2+1$ is odd
(as is the complementary factor $9(m^2-m+1)$ on the left-hand side).
Moreover, once $n \geq 5$ we have $R_n \equiv 11111 \equiv 7 \bmod 2^5$,
so the putative cube root $m$ of $R_n$ would be $23 \bmod 2^5$, making
$(m+1)/8 \equiv 3 \bmod 4$.  Since also $m \equiv 1 \bmod 5$ we'd conclude
that $(m+1)/8 \equiv 4 \bmod 5$ and thus $(m+1)/8 \equiv 19 \bmod 20$.
Since this is not among the four allowed residues we are done.  QED
The same approach deals with some other cases of the repunit-power problem,
but does not settle it completely.  For example, in the decimal case
$9m^q+1 = 10^n-1$ has no solution for any $q \equiv 3 \bmod 4$
(using descent to reduce to the case of odd $n$, and then factoring
$9(m^q+1) = 10^n+8$ as before).  There are no nontrivial solutions for
$2|q$ or $5|q$ (by reduction mod $2^2$ and $5^2$ respectively), and
$q=9$ is a special case of $q=3$, so $q=13$ is the first exponent
(other than $q=1$...) that we cannot exclude this way.
about the "strange step": this feels very artificial, though
I'm not familiar enough with the literature on this Nagell-Ljunggren equation
or related problems to tell if it's a standard technique.
The only other time I remember such a thing working is for a problem
that I concocted for the purpose 30+ years ago:
Prove that the Diophantine equation
$$
y^2 = 7x^2+8x-3
$$
has no positive integer solutions.  There are infinitely many
solutions with $x<0$, such as $(x,y) = (-2,3)$, so there's no easy
congruence argument (though the problem is routine using the
theory of Pell's equation).  However, adding $9x^2$ to both sides
yields $(3x)^2 + y^2 = (4x-1)(4x+3)$, at which point the two-square theorem
soon produces a contradiction
(NB if $x<0$ then $\left|4x-1\right|$ and $\left|4x+3\right|$ are
$+1 \bmod 4$ !).
Comment: Hi Noam. Your "strange step" reminds me of V.A. Lebsgue's solution of y2=x3+7, although it's not as elaborate. First note x must be odd, else 7 would be a square mod 8. Then add 1 to get $$y^2+1=x^3+8=(x+2)(x^2-2x+4)=(x+2)((x-1)^2+3).$$ The last factor is 3 mod 4, so is divisible by a prime $q\equiv3\pmod4$. Then $y^2+1\equiv0\pmod{q}$, contradicting the fact that $-1$ is not a square mod $q$. So similar to your solution, he uses only the computation of $(-1|q)$. I don't know the exact reference, but I think that it was late 19th century, so it's not a new idea.
Comment: @Joe Silverman: yes, that's a clear example of the same idea,
and much earlier than 1980...  Thanks.  Here there are no solutions
at all, but there still doesn't seem to be an easy congruence argument.
(**mwrank** says there isn't even a rational solution, but doing
descents on such a curve isn't elementary either!)
$$ $$
@Gerry Myerson: As I already mentioned, the fact that a decimal repunit
other than $1$ cannot be a fifth power is an immediate consequence of the
fact that all fifth powers are congruent to $0$, $\pm 1$, or $\pm 7 \bmod 25$.
Comment: @Wangt Fei: thanks for Accepting my answer, and for pointing out the typo,
which I'll fix in the next edit when I also acknowledge other comments
and give references to V.Lebesgue's work.   For the descent,
the idea is that if $n=2k>0$ and $R_n$ is a $q$-th power then the same
is true of $R_k$, because $R_k$ is a unitary divisor of $R_n$
(i.e. $R_n/R_k$ is an integer relatively prime to $R_k$).  If $k$ is
also even then $R_{k/2}$ is a $q$-th power, etc., and eventually
we'd reach a solution of $R_n = m^q$ with $n$ odd, to which we can
apply the other argument.
Comment: The review by Nikos Tzanakis of Tom Muller, Note on the Diophantine equation $1+2p+(2p)^2+\cdots+(2p)^n=y^p$, Elem Math 60 (2005) 148-149, MR2188007 (2006h:11038), says that the paper uses nothing beyond Fermat's Little Theorem, and that a direct consequence is that no repunit can be a fifth power. Tzanakis says this extends a result of A Rotkiewicz that repunits can't be squares or cubes, but no reference is given. Strangely, when I go to the webpage that should have the Muller paper, it has all the papers from that issue except Muller's.
Comment: The Zentralblatt review of Muller's paper, by Olaf Ninnemann, says more about the Rotkiewicz paper, Elem Math 42 (1987) 76, Zbl 0703.11016; it's not quite so elementary, relying on Ljunggren 1943.
Comment: It's a great proof for a large range of this problem! Thank you very much. The ideal you already gave is elementary but fascinating. However, I want to point out a Clerical error in the paragraph "The same approach deals with..." that "9m^q+1=10^n-1" should be "9m^q=10^n-1". I did not know much aboult two-square theorem in the composite case. Is it because "4x+3" has a "4y+3" type prime factor then (4x-1)(4x+3) can not be decomposed into two squares?
Comment: I find that if n is even and q≡3(mod 4) and q>3, this method seems not work. If we use descent, k(=n/2) would not be an even number and the equation is not the same as the former.
Comment: @Noam: You're right that there's no congruence argument: $y^2 = x^3 + 7$ is solvable in the $p$-adic integers for all primes $p$. First let's treat $p \leq 7$. If $p = 2$ use $(x,0)$ s.t. $x^3 = -7$. If  $p = 3$ use $(0,y)$ s.t. $y^2 = 7$. If $p = 5$ use $(-1,y)$ s.t. $y^2 = 6$. If $p = 7$ use $(1,y)$ s.t. $y^2 = 8$. If $p > 7$, let $N_p$ be the number of $(x,y) \bmod p$ s.t. $y^2 \equiv x^3 + 7 \bmod p$. Then $N_p = p + \sum (\frac{x^3+7}{p})$, w/ sum being over $x \bmod p$. Call the sum $S_p$, so $|S_p| \leq 2\sqrt{p}$ by Weil's bound. Then $N_p \geq p - 2\sqrt{p} > 3$ (since $p>9$) [contd]
Comment: so there's a mod $p$ solution $(x,y)$ with $y \not\equiv 0 \bmod p$, and such a mod $p$ solution can be lifted $p$-adically.
Comment: For $y^2 = x^3 + k$ with $k \not= 0$: in ${\mathbf Z}_2$ use $(x,k+1)$ s.t. $x^3 = (k+1)^2 - k$, in ${\mathbf Z}_3$ use $(1-k,y)$ s.t. $y^2  = (1-k)^3+k$, in ${\mathbf Z}_5$ use $(x,y)$ s.t. $x^3 + k \equiv 1 \bmod 5$. In ${\mathbf Z}_7$, use $(0,y)$ if $k \equiv 1, 2, 4 \bmod 7$, $(1,y)$ if $k \equiv 0, 3 \bmod 7$, $(-1,y)$ if $k \equiv 5 \bmod 7$, and $(x,0)$ if $k \equiv 6 \bmod 7$. For $p \geq 11$, let $N_p$ be number of mod $p$ solns, so $N_p = p + S_p$ with $S_p=0$ if $p|k$ and $|S_p| \leq 2\sqrt{p}$ by Hasse if $(p,k)=1$. Then $N_p \geq 4$; lift mod $p$ soln w/ $y \not\equiv 0$ mod $p$.
Answer: As expected $(m,n)=(1,1)$ is the only solution in positive integers
of the exponential Diophantine equation $10^n - 9m^3 = 1$.
An entirely elementary proof of this seems unlikely because
any finite list of congruence conditions on $n$ would have to allow
$n=1$ (and also $n=0$, which corresponds to the empty repunit $0$),
and thus could not exclude infinitely many other potential $n$.
A routine but non-elementary solution is to reduce to the three
cubic Thue equations $p^3-9m^3=1$, $10p^3-9m^3=1$, and $100p^3-9m^3=1$
(where $p = 10^{\lfloor n/3 \rfloor}$), and then use an effective and
practical algorithm for solving such equations.  gp takes only
a few milliseconds to process each of
<code>thue(thueinit(x^3-9),1)
thue(thueinit(10*x^3-9),1)
thue(thueinit(100*x^3-9),1)
</code>
and reports that the third equation has no solutions, the second
only $(p,m)=(1,1)$, and the first only $(-2,-1)$ and $(1,0)$.
Since neither $-2$ nor $1$ is a positive power of $10$ we're done.
P.S. I see that quid linked to a page that in turn includes a link to
much the same proof except that the third case (which has no solution)
is disposed of by elementary considerations, namely reduction $\bmod 13$
(and as it happens there's a similar proof $\bmod 7$).
Answer: It is know by work of Bugeaud and Mignotte "Sur l'équation diophantienne $(x^n - 1)/(x-1)=y^q$, II" (see Thm 5) that a repunit in base 10 cannot even be a perfect power (so in particular not a cube).
Another relevant reference is by the same authors "On integers with identical digits" containing among other things the result (Thm 2), which in particular gives all repunits that are perfect powers in all (nontrivial) bases up to $10$:

Let $a$ and $b$ be integers with $2 \le b \le 10$ and $1 \le a \le b-1$. The integer $N$ with all digits equal $a$ in base $b$ is not a perfect power, except for $N=1,4,8,9$, for $N=11111$ written in base $3$, for $N=1111$ written in base $7$, for $N=4444$ written in base $7$.

There are earlier contributions to this problem by others, see the papers for references. (Both papers are freely available online on Bugeaud's webpage  http://www-irma.u-strasbg.fr/~bugeaud/publi.html see year 1999)
It seems there was some discussion of this question on the Mersenne forum a while ago http://www.mersenneforum.org/showthread.php?t=16295 for cubes specifically and also a proof was given (scroll down a bit). I did not study it in detail, but if you want just the result for cubes it seems more accessible, yet it also involves solving Thue equations.
Added: The more general questions to classify all repunits (in arbitrary bases) that are cubes or more generally perfect powers is AFAIK open. It is the question for solutions of the Diophantine equation (with $q=3$ for cubes)
$$\frac{x^n - 1 }{x-1} = y^q$$
mentioned in the title of the paper mentioned above, called  Nagell--Ljunggren equation.
It is conjecture that the set of all non-trivial (i.e., $n,q \gt 1$) solutions $(x,y,n,q)$ is given by $(3,11,5,2)$, $(7,20,4,2)$, and  $(18,7,3,3)$, the former two correpond to the two repunits (that are squares) mentioned in the result I recall above, and the third to the repunit in base $18$ that is a cube mentioned by Gerhard Paseman in a comment.
Yet, as said this is open. But there are numerous partial results, for example:

no other than the mentioned ones (nontrivial) repunit is a square
if there were another cube then it has at least $29$ digits, and the number of digits is a prime and $5$ mod $6$.

In fact in a different terminology, A geometric series equalling a power of an integer, the Nagell--Ljunggren came up a while ago on MO; there some additional informaition and pointers to literature can be found.
Comment: To reduce the chance of misinterpretation, I highly recommend replacing "such a number" by "a nontrivial base 10 repunit"; otherwise someone else might tell you about 343.  Gerhard "Fond Of Repunits And Cubes" Paseman, 2013.05.27
Comment: I agree that 'such a number' is not a good way to phrase this (though I would also say that it is hard to see for me how anything else but the $R_n$ in the question could be meant), and will change it shortly (I want to use the edit also to include something else, which I do not want to do just now).
Comment: From my perspective, "such a number" could include either of the expressions in the title of the paper, or the numbers x,n,y, or q referred to in the title.  I do not mean to say that your wording is opaque or misleading.  I do mean to say that your wording is not bulletproof.  Gerhard "Just Trying To Help Protect" Paseman, 2013.05.27
Comment: @Gerhard Paseman: I fixed (it is hoped) and expanded it. Thanks for pointing out the confusing formulation.
Answer: $\frac {10^n-1} 9$ is not a cube:
Since a cube is either 0, 1 or -1 mod 9, the number of digits in the repunit is
0, 1 or -1 mod 9.
If the number of digits is -1 mod 9, you can show it's not a cube by reducing
mod 19.
If the number of digits is 1 mod 9, reduce mod 7 to show it's not a cube
(except for 1).
Suppose $\frac {10^{9n}-1} 9$ is a cube.
$n =2^k m$ where $m$ is odd.
$\frac {10^{9n}-1} 9$ factors as
$(10^{2^{k-1}9m}+1)...(10^{9m}+1)\frac {10^{9m}-1} 9$ and the factors are
relatively prime, so each must be a cube.
The factors that have a power of 10 plus 1 can't be cubes because a cube + 1
isn't a cube.
Reducing the last factor mod 19, $10^9\equiv -1 (19)$ so $\frac {10^{9m}-1} 9\equiv
\frac {-2} 9\equiv 4 (19).$
$4^{18/3}=4^6\equiv 11 (19)\neq 1 (19)$ so this factor also is not a cube.
So the product can't be a cube.
So no repunit base 10 is a cube.
Comment: If $n=18m+1$ then $(10^n-1)/9$ is $1 \bmod 7$, which is a cube.
Comment: More generally, for any modulus $M$ relatively prime to $3$, if $n \equiv 1 \bmod \phi(M)$, then $(10^n-1)/9 \equiv (10-1)/9 \equiv 1 \bmod M$, so there is always an arithmetic progression where $M$ cannot be used to prove $(10^n-1)/9$ is prime.

Can repunits be perfect cubes?


Can I mix TMC drivers with A4988 on the same RAMPS board?

Question: The closest thing I can find is this wiki page that state DRV8825 and A4988 can be mixed. However, the TMCs seem different, requiring more connections and offer more features, so I wonder if they can be used on the same RAMPS board with A4988, particularly for X and Y axis.
Comment: If you're going to use modern drivers with SPI or UART connections, you should probably invest in a board that supports them natively (SKR 1.3, 1.4; Fysetc F6, S6; MKS S GEN L) - it's a lot cleaner then compared to monstrous wire harnesses.

To use different drivers - and mix them - just define each driver as the correct type in your configuration.h file:
https://github.com/MarlinFirmware/Marlin/blob/2.0.x/Marlin/Configuration.h#L687
Answer: Yes you can mix different drivers, including the TMC drivers (e.g. using for X and Y only).
How you do that is described in this instructable.

Please do note that, from observations, the 8-bit based Arduino boards and shields such as the RAMPS are becoming more or less obsolete; the 32-bit based controller boards are becoming mainstream. Such boards have a lot more potential in execution speed, memory and more available options for peripherals.


What are the differences between meritorious acts and wholesome acts?

Question: A detailed answer with references is highly appreciated!
Comment: Do you mean the difference between "Kusala" and "Punna" ?  I'm curious to see the answers too.  Buddha used those two words in many suttas.  They are interchangeable words.
Comment: in satipatthana, Buddha said true kusala is satipatthana 4. I have not read all the suttas, but I have yet to see if Buddha used "punna" to describe satipatthana 4.  other than that, kusala and punna are interchangeable as far as i know.  I just want to point out, in contrast, Buddha described 5 hindrances as true "akusala" .  Your question can further branch out to the difference between Akusala and Papa.
Comment: thanks Dewmini, i had to double check check my fact.   topic of Kusala and Punna is not as easy as Akusala and Papa (where Buddha often used these terms together in many suttas, example " pāpakā akusalā dhammā" ).  I got the idea that Kusala and punna could be interchangeable from Abhisanda Sutta: Rewards. "..This is the first reward of merit (pali-punna), reward of skillfulness(pali-kusala),.." .  this part of the sutta shows the commonality of Kusala and Punna.  Kusala and Punna could be a good thesis for Master or Ph.D research.
Comment: Yes it can be branched out to Akusala and papa also. I think punna and kusala are not interchangeable. Roots and targets seem to be different.
Comment: Actually punna, or meritorious acts can be listed. There are ten of them. https://en.wikipedia.org/wiki/Merit_(Buddhism)#Merit-making
Answer: When we discuss virtuous living and behaviour according to the Buddha's teaching, two special Pali words are used - kusala and punna. Kusala has come to mean 'karmically wholesome', while punna is taken to mean 'merit'.
Often Buddhists in Sri Lanka use the two words to describe one and the same kind of activity - "meritorious". However it would be good to look at these two words in the context of the Buddha's discourses.
There is a difference in the two words, and have to be taken in the context in which they are used. The Buddha has said, "Accumulate much wholesome actions." He has used the term 'wholesome' in the practice of the Noble eight-fold path, and development of tranquillity and insight.
Merit is the term often used to describe actions that bring about spiritual welfare and contentment. He has discoursed, "Bhikkhus, 'pleasant disposition' is another word for 'merit." That would mean one should engage in meritorious deeds to receive a life of comfort and contentment. He has also said that it is an auspicious event in life to be possessing previously accumulated merits.
There is a view among a few lay people as well as monks today that since merits prolong the process of existence and the round of rebirths, one needs to accumulate only wholesome actions and not merit. One gets into debate about merit and wholesome actions due to non understanding of the reasons for the continuance of the round of rebirths. Round of rebirths occur due to Dependent Origination.
If the continuance of the round of rebirths occurs due to Dependent Origination, the latter must cease for the round of rebirths to cease occurring. The way to make that happen is to follow the Noble Eight-fold Path. To fulfil that process, one needs to association of noble friends, hearing the Doctrine and keep company with righteous people. He would also need a rebirth conducive to fulfil the process of following the Noble Eightfold Path. Now, that is where merit plays its part.
A rebirth in worlds of the Brahmas and Devas becomes a very helpful asset to one who searches for the goal of Nibbana. Such rebirths are the results of merits. So we must understand the true worth of merit. Those who spend the time arguing "We do not need merit but only wholesome deeds" unfortunately may end up getting neither.
Undoubtedly, it would be a wholesome action to have a thorough understanding of Merit and wholesome actions before one would discuss them. Trying to discredit merit can only result in accumulating unwholesome actions. The Buddha has this to say about merit: "If one has enthusiasm to do a meritorious deed, do so over and over again. Develop a desire to do merit. Merit is comfort."
The Buddha's consistently emphatic message is to annihilate desire. However, He exhorts desire for merit because merit is needed to make our lives comfortable and conducive to search the goal of Nibbana. Our birth in this world and all our good achievements are results of accumulated merits.
There are those who may say that in today's world many things need money and therefore even doing merit can be expensive. However that may be, money and merit have no real proportion. Merit is something that does not measure and count with money. Merit is based on a non-aggressive and virtuous mentality.
Merit has its origin in right thinking. It is the right thinking that teaches us the benefit of selfless giving, benefit of merit, that good and bad actions have similar outcomes, there is benefit in taking care of one's parents. To say that one cannot do meritorious actions for want of money would not amount to right thinking.
Observing the five precepts, observing the eight precepts on Poya day, Contemplation of the Buddha, Contemplation of the Dhamma and Contemplation of the Sangha, and meditation on loving kindness do not cost money. In short, we can earn merit even from the dish water we throw away. Thus the talk that merit is costly may be misleading to those who don't have money as well as to those whose wealth is more than they can count.
Answer:
Meritorious act - an act not necessarily devoid of the unwholesome roots. E.g. you give expecting some positive result in the future, hence with some attachment
Wholesome act - and act devoid of unwholesome roots. E.g. giving with the motivation it will create the conditions for liberation.

I believe the former is recent development. E.g. the Abhidhamma talks only about wholesome deeds and does not make distinction about meritorious deeds. Wholesome deeds can be associated with the right view or wrong view. Here the right view is some belief of Karmic retribution. This would be valid not non Buddhist religions like Hinduism or any other religion with has the view that actions will have some Karmic retribution. See: Karma, Karma in Buddhism
Dana Sutta discusses different levels of giving in which different results can be reaped. If you make a distinction between meritorious and wholesome as discussed earlier perhaps the last 1 or 2 forms of giving can be considered wholesome and the rest as meritorious.


Somebody else's domain name is pointing to my server IP address and Google is indexing my content on their domain

Question: I am in the middle of updating to https. I changed our DNS A record to point to the new ip that was provided by the host on Oct 31st. Now when I google our company name, the first entry is our website at www.rainstor.com. They have the same ip address according to Whois. My web hosting company says it is not their problem that the other company is pointing to our website! Can anyone help? Has anyone had this problem before? If so, who is responsible, hosting or rainstor?
Comment: Is the other domain name showing your content when you go to that address?   If so that is the problem.   It can be fixed either by changing the DNS records for their domain (which you don't have access to), or configuring the web server not to show your content for that other domain.
Comment: I was a bit confused by your question just a bit. To clarify, you have a domain name pointing to an IP address and somewhere in the world, there is another domain name pointing to the same IP address. Since you are using a dedicated server with your own IP address, then the unknown domain name is resolving to your site --or-- since you are on a shared server, when you try and access your site using an IP address, you get another site. Please clarify which scenario we are talking about. Both do happen from time to time, however, the answer depends upon the scenario.
Comment: "To clarify, you have a domain name pointing to an IP address and somewhere in the world, there is another domain name pointing to the same IP address", Yes. And yes, we are using a shared hosting server.
Comment: Thanks Stephen & closetnoc! Working with the hosting company to send a 404 response for rainstor.com requests... I really appreciate the help :-)
Answer: To answer the question, "who is responsible", the only people who can change the DNS record for rainstor would be whoever has control of their DNS records. It might be rainstor directly or it might be a subcontractor or service provider of theirs.
I don't really see it as a problem that they haven't updated their DNS records. It really is their problem and not yours. I can see it's a bit of a nuisance for you, but the important thing is you have your A record setup correctly and it points to the server that you control.
There are measures you can take to prevent your content from appearing on their domain:

configure your server to send back an error for any address that matches a URL that doesn't contain your correct domain. The actual message could be a '505 server error' or '404 not found' or '401 not authorized' or '301 moved' (which will redirect to a different URL of your choosing). Basically, anything you want.
use a Rewrite Rule, or
use a Virtual Host configuration, or
write code into the sites PHP (if that's what you're using) to deliver appropriate headers

The actual solution will depend on what server software you are using.
Answer: Edit your .htaccess file and rewrite the rule to return "Gone" status for any url that's not yourdomain.com
<code><IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} ^yourdomain.com$ [NC]
RewriteRule ^ - [G]
</IfModule>
</code>
Comment: You can also set a different flag from here: https://httpd.apache.org/docs/2.4/rewrite/flags.html
Answer: The DNS A record governs where all requests go, everything else is irrelevant. After a client requests your page, that request is handled by the destination server at the IP address you set the A record to. That destination server configuration determines what type of connection(s) you support - HTTP, HTTPS, and optionally a redirect to one or the other type.
What may be confusing things is DNS propagation time. You can test for yourself at a site like whatsmydns.net to see which A records are being served (you very well may find the old IP address is still being returned for a day or two).
You can safely ignore anything to do with the old hosting company now that you have switched to HTTPS and a new host. Very soon all requests for your site will be directed to the new IP address you set with the new DNS A record.
One tiny thing to double-check, make certain you only have one DNS A record. It is technically possible to use multiple but this is probably not what you want, especially if the second record is still pointing at the old host's IP address.


How long can a comment be?

Question: am less than 3 days old on this site and am just loving it. I browse with my phone a lot as that is easier to access the net from where i come from. I use sony ericsson k800i and sometimes find little difficulties. I had to comment on someone's submission and could not post as I was told -167 characters remaining. I know it was wrong but i had to post in the YOUR ANSWER box and that went through.
I will like to know what if its the same on pc and if there are other limitations when using the mobile version.
Once again, am happy to be part of this.
Answer: 600 characters. On any device, its more apparent on a computer as there is some Javascript that lets you know how close you are to the end of the limit.
Glad you are enjoying yourself on the site.
Answer: Please don't use the answer box for comments. Answers are supposed to answer the original question, not to be used to reply to other answers. Answers that should be comments usually end up getting flagged by users and either deleted or converted to a comment by a moderator.
Also, avoid lengthy discussions in comments. They are meant for asking for clarifications and pointing out errors. If you find yourself going over the limit, that's usually a good sign that you should take the discussion to a chat room instead.
Comment: Thanks a lot guys, but i will also like to know what the TICK sign, (right below downvote sign) is for.
Thirdly, where or can I post any interesting stuff, not questions but some important relevant findings that demands thoughts and views?
Comment: @Nok that is to accept the answer. accept the answer that is most useful to you the asker.
Comment: By accepting the answer, you a. Tell everybody else you found that answer to be most useful, b. Give that person 15 points, and c. Earn yourself 2
Answer: As wax_eagle noted, the character limit is 600, no matter what platform you use. Only how well that limit is presented varies by platform.
Let me suggest, however, that of you are hitting that limit, you are using the system wrong. SE differs from much of the rest of the internet in that it is not a social network OR a discussion forum. Back and forth engagement of ideas is discouraged in favor of clear concise questions and their corresponding answers. The comment mechanism is provided as a small feedback mechanism to improve the quality of posts, specifically not add a full on way to engage in a discussion of an issue like a comment form on a blog might.
If you find yourself wanting to do that, please consider that you are using the wrong tool for the job. Some of our community can be found in the site chat rooms where you can engage at length, but please reserve the QnA part for clear answerable questions and concise accurate answers and the comment space for furthering those goals, not detracting from them by turning posts into discussion threads.

How long can a comment be?


Dropbox folder sharing - options for email address is not there after upgrade to windows 7

Question: I have just been upgraded to Windows 7. Now my Dropbox folders are no longer sharing, and the option to share with another email address is no longer there?
Answer: They changed the way to share with dropbox (using the desktop application). The easiest way I found is to do it via the dropbox site itself. One way to get to it is right clicking the dropbox icon and clicking 'Launch Dropbox Website', log in if you are not already logged in.
https://www.dropbox.com/share
After logging in to dropbox and going to the above url, simply click: New Shared Folder and go through the process of sharing. Your folders will appear like normal folders but their contents will be shared.
One can also add new users to a share at the same place, simply select Options of the shared folders and follow the directions.


Word to describe a person who expresses his or her feelings frequently?

Question: I'm looking for a word to describe a person (it can be a term of animal behavior) who expresses his or her feelings frequently, particularly through facial expressions.
Answer: Consider demonstrative

(of a person) tending to show feelings, especially of affection, openly.
Answer: You might also consider the word effusive

expressing feelings of gratitude, pleasure, or approval in an unrestrained or heartfelt manner
Comment: effusive however is only for a select class of feelings (it doesn't address a person frequently expressing anger, for instance).
Answer: Expressive is the word I would use here, such as, 'That person has an expressive face; it shows their emotions quite clearly.' Another suggestion may be emotive if they are always expressing how they feel.
Finally, the idiom "wears their heart on their sleeve" is used to describe someone who it's very easy to tell how someone feels.
Answer: Emotional
From the ODO:

(Of a person) having feelings that are easily excited and openly displayed: he was a strongly emotional young man


Is it legal to imitate a game without publishing it

Question: If you're developing a game that's very similar to a game that's already published, both the game mechanics and the graphics but you're not publishing it, instead you're keeping it in your own computer.
Is it legal to do so?
Comment: If it's staying on your private computer, how would anyone find out about it to pursue legal action against you?
Comment: Related question: [How closely can a game legally resemble another?](https://gamedev.stackexchange.com/questions/1653/how-closely-can-a-game-legally-resemble-another)
Comment: @DMGregory If this board was more "personal" (like reddit) I would say go for it since in 99.99% of cases no one will care if you just mess around for yourself (not even a company as protective as Disney). But since we should be trying to answer this from a pure legal perspective we shouldn't encourage people to break the law just because "no-one will find out".
Answer: Generally speaking, copyright law does not have an exclusion for "private use" or similar (depending, perhaps, on your jurisdiction). Violating copyright is violating copyright, regardless of whether or not you then further redistribute the work by making additional copies for "publication."
So no, it is not legal.
Of course, that doesn't stop people from doing it.  From a practical perspective, of course, it's unlikely anybody could discover your violation. That doesn't make it "okay," but it significantly decreases the risk factor in many peoples' minds. Often you will not see entire games copied, but people using bits and pieces of artwork as "placeholders," et cetera.
Personally I wouldn't recommend this - it's very easy to accidentally keep a piece of copyrighted artwork in a game when you actually ship it, for example.
There's also "fair use" doctrine in some places, like the US, which is a defense for certain limited kinds of use such as parody or education. It's important to note that this is a defense, which means you have to be taken to court to prove your case, so it's not something you should rely on if your goal is to avoid being sued.
Note that none of this applies to imitating "game mechanics" or ideas. Those cannot be covered by copyright. Copyright covers work in fixed form, such as art and sound.
Comment: Thanks for the answer. When you mentioned that "Copyright covers work in fixed form, such as art and sound", does it mean that if someone make an imitation of a game with not **exact** artwork but rather similar artwork that **has the same theme**, it's still considered copyright violation?
Answer: I don't see why not. If you are keeping the game to yourself (not publishing it) it would be fine. Some companies may even allow you to publish an imitated copy of their game as long as you aren't making money off of it (ad revenue, making the game cost money, etc). It would be helpful if you could edit your question so that we know what game you are planning to imitate, but overall it should be legal, as long as you don't publish it.
Comment: Thanks for the answer, basically I tried to make a game that's similar to Balloons TD 5
Comment: Yeah, that's perfectly fine. There's tons of similar tower defense games out there to BTD5.
Comment: Sorry but I have to downvote this. This answer does not seem informed but simply an opinion. In fact, what Josh said in his answer is most likely the true in most countries / states. I don't know of any country where the amount of people using a product changes the copyright laws.


Late to file S-Corp taxes in US

Question: I have a small one person s-corp in USA. It's now almost first day of summer; however, I still haven't filed my corp taxes due to some personal issues. What do I do at this point? Should I just fill my taxes using TurboTax? What is the late fee?
Answer: You should file ASAP. Penalties are pretty expensive: $195 per month per shareholder. If you haven't paid, you'll also pay 0.5% per each month you're late, so if your tax is $1000, you'll be paying $200 per month until you file and pay (that's in addition to the regular interest on the late payment).
There are additional penalties for late filing of K-1, which may also be applicable. Also, if you're late on your payroll forms (and payments), you may be subject to much more severe "trust fund recovery" penalties.
Comment: I don't have any employees and don't file any payroll forms, so hopefully I am not a subject to more severe "trust fund recovery" penalties
Comment: @VladMiller what do you mean you don't? What about yourself?
Comment: I don't pay myself a salary; Should I?
Comment: Yes, you should. Officers of a corporation (any corporation) must be paid a *reasonable* salary. By not paying yourself salary, you're essentially evading payroll taxes, the IRS doesn't take it nicely. Get a tax adviser (EA/CPA licensed in your State) to help you understand what the requirements are.
Comment: I would definitely find experienced CPA to help me. Is there any good article you can suggest me to read first?

Late to file S-Corp taxes in US


Idle state detection for server

Question: Windows OS has a service that detects idle state. Details: Task Idle Conditions
The computer is considered idle if all the processors and all the disks were idle for more than 90% of the past 15 minutes and if there is no keyboard or mouse input during this period of time. When the Task Scheduler service detects that the computer is idle, the service only waits for user input to mark the end of the idle state.
It is very useful for usual PCs that have keyboard amd mouse. We can use standard task scheduler to start some process like defrag when PC in idle state and stop when PC isn't in idle state.
But what should we use when we using a standalone server without keyboard and mouse? Server sometimes receives commands by TCP/IP and starts CPU and HDD activity. But sometimes CPU and HDD activity at zero level.
I would like to use this periods of time to start defrag or another process. But this started at "idle" state processes should be terminated when another commands will appear. So, standard idle state conditions cant help me because we have not got user input to stop idle state. I need more customizable idle state detector. Automatically started processes shouldn't influence to idle state, but PC should go away from idle state when another process will apperar. What should I use?
Maybe exists some advansed task scheduler?
Or I should write some useful utility on C#?
I hope that it is a standard task and all useful utilities already compiled :)
Answer: if no user input is available the server should monitor idle time itself using
<code>BOOL WINAPI GetSystemTimes(
  _Out_opt_ LPFILETIME lpIdleTime,
  _Out_opt_ LPFILETIME lpKernelTime,
  _Out_opt_ LPFILETIME lpUserTime
);
</code>
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Idle state detection for server