Is the electron a pointlike particle? And if yes, how is that possible, because the energy then would diverge, wouldn't it?

Question: My problem is that I read (besides others in this post Why are electrons and quarks 0-dimensional?) that the electron is a point-like particle. My question is on the one hand whether that is true and on the other hand if the electrostatic energy of the electron would not diverge if it was a point-like particle?
Comment: related: https://physics.meta.stackexchange.com/q/13940/
Comment: The electrostatic self energy is not addressed in the proposed duplicates so I vote to reopen it.
Answer: A point particle is a mathematical concept, so in a way your question does not make sense. However, what we know is that with all  experiments that have ever been performed, there is no indication that an electron would have a certain size/volume or substructure. Theoretically we know that there is something we don't yet fully understand when we would try to probe below the Planck length, but that is so far from current experimental possibilities.  But to come back to the first sentence of my answer. A particle is a classical / macroscopic concept, like a particle of dust. It is an approximation physicists make to solve problems. In reality an electron is the excitation of an electron field. Nothing less, nothing more.
Comment: Physics is a mathematical model of reality and thus every physical notion is a mathematical concept. The question can then be taken to mean whether there is any observed deviation from the mathematical concept of a point charge. As such the question makes complete sense.
Answer: I think you are referring to the diverge of the electrostatic energy of a point-like particle. In classical electrodynamics that is the energy of the electric field which is associated to the charge of the electron. As you are saying, the $1/r^2$ energy of the field diverges at the r=0 position and even its integral from 0 to infinity would diverge.
The solution to this apparent paradox lies in what it means to be point-like. In quantum field theories, such as quantum electro-dynamics, as r approaches zero you need to consider quantum fluctuations, which, among other things add new charged particle in a cloud around the electron.
Therefore, when $r\sim1/m_e$ it is likely to see not just a naked electron, but an electron surrounded by a pair of particles (total 3 particles!): the original electron, one "virtual" positron and one "virtual" electron, which can exists only for times and separations comparable to $m_e$.
This makes the energy of the "point-like" electron much better behaved at short distance. Still, it diverges as the logarithm of the shortest distance you consider. In the end you have to consider renormalization of the theory to get finite answers.
Answer: First, my version of the divergence problem is a self-interaction problem. In classical electrodynamics, an electron generate a Coulomb potential, which diverge at the center, but the electron itself is sitting directly at the center, so it appears that the electron has infinite potential energy, due to the Coulomb interaction with itself.
There are, of course, more modern way of describing an electron and the laws of Electrodynamics, this is called Quantum Electrodynamics(QED), and is part of a more general theory called Quantum Field Theory(QFT). They are believed to capture the very small length scale nature of electrons.
In quantum field theory, an electron is described by a field. Moreover, this field obey some conservation laws. These properties allow us to think about it intuitively as "fluids" dispersed throughout space. They can form a sort of plane wave or a more localized wave-packets.
The divergence problem doens't go away just because we chose to describe electrons as "fluids", instead the infinite self-energy problem became the biggest problem in QFT, leading to inifite results when we calculate finite physical quantities. This problem was finally resolved by a method called renormalization, which is another fascinating story that I shall not elaborate.
In conclusion, the modern view of electrons, as least when you go to small enough scales, is with fields instead of a point. The divergence problem, however, exist in both cases, and is one of the deepest and most interesting problems that has haunted physicists for many generations.
Answer:
My question is on the one hand whether that is true

In the mainstream standard model of particle physics all  elementary particles in the table are axiomatically assumed to be point like.The calculations of the standard model, a quantum mechanical field theory, fit the data and are very predictive, and thus one accepts that the axiomatic hypothesis is correct.

and on the other hand if the electrostatic energy of the electron would not diverge if it was a point like particle?

This would be true for a classical particle, in classical electrodynamics. The electron, as all other particles in the table, is a quantum mechanical entity. Its footprint on a screen is the footprint of a particle. An accumulation of data on electrons with the same boundary conditions shows the quantum mechanical probability distribution of its wavefunction. The probability distribution avoids the singularity of the 1/r classical potential, as the space location of a given electron is random, before the wave function can be seen in the accumulating many measurements.
This double slit experiment with single electrons passing the same boundary conditions of two slits is instructive

Fig. 2 Single electron events build up  an interference pattern in the double-slit experiments.

The electron footprints  look random, until a large accumulation is gathered where it shows the wave nature of the probability of finding an electron at the (x,y) of the screen.
Also understanding the hydrogen wave function solutions of the Schrodinger equation , where the 1/r potential is there to constrain the solutions, may help. The 1/r singularity affects the type of solutions for the wavefunction, but there is no singularity in the wavefunction.
Edit after comment:
This is the state of mainstream physics. This does not mean that experiments are not trying to find what the size of an electron is. Recent results on the size of the proton, a composite particle,

The result, published in Nature on 6 November, puts the particle's radius at 0.831 femtometres.

For the electron , a classical "radius" can be measured ,as in this answer and links therein:

In QED, electrons are only point-like, which makes quite a difference. In the context of scattering experiments, the electron size is determined by the form factors, which are not those of a point particle, due to radiative corrections

.....

The particle data group (the official source for particle properties) lists on p.109 of its 2014 report the value $2.8⋅10^{}$m as ''classical electron radius''

The fact is that there is no "wave" in space for the individual electron, as the above double slit experiment shows with the foot print of individual electrons, and the hypothesis of its being a point in quantum mechanical calculations holds as far as data goes.
Comment: It would be convenient to add that the standard model is built on quantum field theory, where particles do not have any wavefunctions but are excitations of fields, and so avoid confusion because you immediately talk about wavefunctions after mentioning the SM.
Comment: maybe worthwhile to add that, whereas non volume effect has been detected for the electron, volume effects have been measured for some other particles like the proton (albeit not an elementary particle).
Comment: @ZeroTheHero  edited
Answer: This is an excellent question. We know from experiment that the electron behaves like a point charge to all accessible scales, that is no deviation from the potential of a point charge has been observed. This indeed leads to a diverging self energy. Main stream physics has no answer to the question how this is possible.
Comment: Not sure why this is downvoted, I'm a layman but I thought these statements were correct.
Comment: @electronpusher  Sometimes people just like to downvote anonymously and without motivation.
Comment: This answer is spot on. One could also add that nobody come up with a better model (people tried, like born infield for the infinite energy, but this cannot be quantized; finite sized electron, but this had among other problems that the mass doesn't transform correctly).


Is cruel and usual punishment constitutional?

Question: The U.S. Constitution's bill of rights prohibits "cruel and unusual punishment". I am asking about a catch: cruel and usual punishment. If a punishment were determined to be cruel but is commonplace would it be constitutional?
Comment: Well any punishment can be considered cruel, tecnically
Comment: @IñakiViggers I suppose you meant to ask for a punishment that is cruel but usual (or at least not unusual)?  Such punishments are the ones whose constitutionality would depend on the answer to this question.
Comment: @phoog You are right. Thanks for noticing that. To avoid confusion I'm replacing my comment with the one that follows. Thanks again.
Comment: You might want to give a real-life (or at least realistic) example of punishment that is *cruel and usual*. That would contextualize your question and make it less rhetorical or speculative.
Comment: @IñakiViggers under the Khmer Rouge in Cambodia it was common to tie prisoners naked on top of an ant nest and cover them in honey, or similar procedures. Cruel and usual punishment... Just one example.
Answer: As a preliminary note, the mandate that "Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted" can be interpreted two ways, (a) prohibiting punishments which are cruel as well as those which are unusual, or (b) prohibiting just those which are both cruel and unusual. The courts have not interpreted this to have meaning (b), even though "cruel and unusual" is a fixed phrase repeated in court rulings.
In various cases where the "cruel and unusual" clause is invoked, e.g. Solem v. Helm, 463 U.S. 277, Weems v. United States, 217 U.S. 349, Robinson v. California, 370 U.S. 660, Lockyer v. Andrade, 538 U.S. 63 the courts consistently analyze the punishment in terms of being jointly "cruel and unusual", and never consider the possibility that a punishment might be cruel but usual, or unusual but not cruel.
The prohibition derives from the pre-American "cruell and unusuall Punishments" provision of the English Declaration of Rights, analyzed in Harmelin v. Michigan, 501 U.S. 957, which provides "[t]hat excessive Baile ought not to be required nor excessive Fines imposed nor cruell and unusuall Punishments inflicted". The court observes that cruel punishments can indeed be quite common, for example

But the vicious punishments for treason decreed in the Bloody Assizes
  (drawing and quartering, burning of women felons, beheading,
  disembowling, etc.) were common in that period -- indeed, they were
  specifically authorized by law, and remained so for many years
  afterwards.

The court concludes from its historical analysis that "unusual(l)" in the context of English common law really means "illegal", i.e.

"contrary to Law and ancient practice," without "Precedents" or
  "express Law to warrant," "unusual," "illegal," or imposed by
  "Pretence to a discretionary Power."
Answer: The U.S. case law doesn't have a clear black and white resolution of that issue, which plays out differently in particular fact patterns on mostly a categorical basis under existing, much criticized case law. Pretty much, 8th Amendment jurisprudence in the U.S. can be summed up as follows:

Many kinds of corporal punishment short of the death penalty are prohibited as punishment even if similar uses of physical force were legal to secure someone's arrest or for the purposes of maintaining order in a prison or jail.
The death penalty in various circumstances (e.g. rape of an adult woman, ordinary crimes not resulting in death or a strong presumption that a death has occurred, offenders under the age of eighteen when the crime is committed) is barred by the 8th Amendment.
Life in prison without possibility of parole for a person who was a minor when the crime was committed violates the 8th Amendment.
Very long sentences for very minor crimes for first offenders (e.g. life in prison for writing a bad check) are prohibited.
There is almost no limitation on long sentences in prison sentences for adult recidivist felons. The 8th Amendment as interpreted by existing case law allows a life without possibility of parole sentence for non-violent shoplifting of about $100 by a person with multiple prior felony convictions, for example.
The circumstances under which long solitary confinement is prohibited by the 8th Amendment an unresolved issue upon which there is a split of legal authority that has not been definitively resolved.
Imprisonment of someone for failure to pay a debt that they are unable to pay, is prohibited, although incarceration for willful failure to pay a debt that someone is able to pay, or for failing to attend a hearing or respond to duly issued interrogatories issued to a debtor in the debt collection process, is not prohibited.

The reasoning behind these determinations is not entirely consistent between particular sub-types of punishments prohibited by the 8th Amendment.
There are also multiple statutory and non-8th Amendment grounds upon which sentences can be contested.
For example, a sentence in excess of the maximum punishment authorized by statute for the crime of conviction by a jury, in a case where there is a right to a jury trial, is invalid, but not under the 8th Amendment.
Similarly, disparate statutory sentencing rules for statutory rape based upon gender have been struck down on 14th Amendment equal protection grounds.
As a third example, a sentence (e.g. a death penalty determination) may be struck down because adequate due process was not provided when it was imposed or state law was violated when it was imposed.
It also bears mentioning that 8th Amendment issues are evaluated at the time they are litigated based upon "evolving standards of decency" rather than under the standards of what would have constituted cruel and unusual punishment in 1791 when the 8th Amendment was adopted. A precedent from 1810, for example, under the 8th Amendment, is not necessarily binding in 2020.


How to install & run Xmind v. 8 in Ubuntu 16.04?

Question: How to install & run Xmind v8.0 in Ubuntu 16.4 (ZIP file) with command line ?
Answer: @Rinzwind is cheating :)
In case you are using the "regular" -official Xmind -version for Linux:

Xmind used to be available as .deb file, but from version 8, there is currently no .deb file available. It can still be run very well on Debian-based systems however.
How to use
The most easy setup is to run it locally, since the application needs to be in a writable directory. The application comes with a setup.sh. Unlike what you would expect, this does not install the application itself, but it installs a few shared libraries it uses, and a few fonts to be used with Xmind.

Download the latest Xmind from here (.zip)
Unzip xmind-8-linux.zip, move the unzipped folder to any location you like where you have write permissions
Open the folder (or cd into it if you are on cli), and run the setup.sh script with sudo, to install some libraries and fonts (simply type sudo and drag the script on to a terminal window and press Enter).
Now we will run Xmind for the first time, during which we will be able to create a launcher for Dash and the Unity Launcher:

Inside the xmind-8-linux folder, open either the XMind_amd64 or XMind_i386 folder, depending on your architecture, and double click on the Xmindexecutable. The application will start.
In the Unity Launcher, the Xmind icon will appear. Right-click on the icon and choose "Add to Dash"

Log out and back in, and your setup is ready to use, Xmind is available to Dash.

Explanation
To run Xmind, you can create a .desktop file manually, however, you can also let Unity do the job for you, as explained here and here. An Xmind icon is automatically copied to ~/.local/share/icons/xmind.png for local use.
Note
I tried the latest version (8) of Xmind for a few hours, and to be honest, I prefer previous version(s) with less (or no) "advertising", and a more intuitive interface (which is opinion-based of course).
It seems I am not the only one in that, since Xmind makes previous versions available here. These version(s) include .deb installers. These versions run perfectly fine on 16.04.
Answer: Download this link http://www.xmind.net/xmind/downloads/xmind-8-beta-linux_amd64.deb
Either doubleclick the finished download in your ~/Downloads and let software center install it.
Or enter commandline and do
dpkg -i xmind-8-beta-linux_amd64.deb

on the finished download.
The 1st should be preferred. The 2nd would require you to download and install all the dependencies manually too.
Comment: I googled it :D :D http://www.xmind.net/download/beta/
Comment: Zip tends to be WINDOWS. You need .DEB. A zip in linux would be a source file so a DEB is preferred (since Ubuntu used DEB natively)
Comment: You are a cheater! :)
Comment: Just curious, how did you find this one? It is not here: http://www.xmind.net/download/linux/
Comment: I did too, but no matches to `.deb` i.c.w. `xmind`. It must be a conspiracy...
Comment: Hi @Rinzwind , Very very thank you so much for help me :-) but i learn from install ZIP file from command line.
Comment: @Rinzwind great solution, great thread!!!
Answer: If after installing XMind, any method you can not launch it as stated by  @quickstop. The problem may be with the way Java 9/10/11 treats the classpath, it seems that Xmind is using an old eclipse version.
The trick is to tell eclipse to use a Java 8 version.
./XMind -vm /usr/lib/jvm/java-8-openjdk-amd64/bin/java

Tells eclipse to look for java at /usr/lib/jvm/....
BTW the deb file contains an older version of Xmind.
If you do not want to use a command line modifier you can always include the
-vm <your path to java exec>

flag in the XMind.ini file
Comment: On https://www.eclipse.org/forums/index.php/t/198527/ you may find the rationale for this.
Comment: That seems to work, but is there a way to permanently make this change? Thanks!!
Answer: I have written a bash for installing XMind from zip file.
Here is Github repo https://github.com/dinos80152/XMind-Linux-Installer
The installation includes

Installing dependencies
Extracting xmind zip file to /opt/xmind
Creating XMind command
Creating launcher, MIME and icon
Creating workspace
Setting XMind.ini
Updating MIME database, Desktop database, and font cache

Everything is done by one script, you don't have to do anything else by yourself. The /usr folder is copied from XMind 8 beta version deb file.
It also has an uninstall bash script.
Any question and advice, leave issues in github repo.
Answer: SOLUTION: Script file that installs XMind 8

I'm very surprised that XMind has left the Unix users with such frustration for installing XMind 8.
To solve the problem I wrote a bash script that installs XMind 8. I have tested it with Ubuntu 16.04.2. This will also install the XMind menu item and its icon.
#!/bin/bash
 #xmind8Install.sh
usage=$(cat << EOM
USAGE:
  -This script works with "XMind_amd64" only (not i386, 32-bit)! Tested with Ubuntu 16.04.2
  -Best to just copy this script file into the same directory as the downloaded xmind-8-update1-linux.zip
    file (or whatever you called it).
  -This script will create a final direcoty 'xmind8' to install into but you need to pick where you want that 'xmind8' directory
    if you don't want the default of '$HOME/.local/bin'.
xmind [/path/to/downloaded_xmind_file-name.zip] [/path/to/where/you/want/to/install (DEFAULT: $HOME/.local/bin)]
EXAMPLE:
  sudo bash $0 xmind-8-update1-linux.zip
  sudo bash $0 Downloads/xmind-8.zip
  sudo bash $0 xmind-8-update1-linux.zip $HOME/apps
  sudo bash $0 xmind-8-update1-linux.zip /opt
\n
EOM
)
[[ ($# < 1) || ("$1" == "--help") || ("$1" == "-h") || ("$1" == "-H") ]] && echo -e "${usage}" #Displays help/usage info
function fCHECKSUDO { # checks to make sure the script is being run as root
    if [ "$(id -u)" != '0' ]
    then
            echo -e "\n   $(tput setaf 1)This script has to be run as root! ($ sudo bash ...)$(tput setaf 9)\n"
            exit 1
    fi
}
fCHECKSUDO
type unzip >/dev/null 2>&1 || { apt-get install -y unzip; } #This installs the package 'unzip' if it is not already installed.
fileZip="${1}"
installDirRoot="${2:-"$HOME/.local/bin"}"
 #echo '$fileZip='$fileZip " " '$installDirRoot='$installDirRoot
function _installXMind8 {
    ##user preferences seemed to be saved into: xmind/workspace/.metadata/.plugins/org.eclipse.core.runtime/.settings/
    ##http://www.xmind.net/m/PuDC a beta DEB package
    ##To find the icon images: $ find ~/bin/xmind8 -iname xmind.*.png
    #[[ ! -f "$fileZip" ]] && wget -t 4 -O xmind8.zip "https://www.xmind.net/xmind/downloads/xmind-8-update1-linux.zip" ##xmind.net is blocking non-browser downloads
    [[ ! -d "$installDirRoot" ]] && mkdir -pv "$installDirRoot"
    unzip "$fileZip" -d "$installDirRoot/xmind8"
    "$installDirRoot/xmind8/setup.sh"
xmindini="$installDirRoot/xmind8/XMind_amd64/XMind.ini"
   cp $xmindini ${xmindini}.BAK
   oneDot="${installDirRoot}/xmind8/XMind_amd64/"
   twoDot="${installDirRoot}/xmind8/"
   sed -i "s/^.//${oneDot////\/}/g" $xmindini
   sed -i "s/^..//${twoDot////\/}/g" $xmindini
cat <<-EOF > $HOME/.local/share/applications/xmind.desktop
   [Desktop Entry]
   Type=Application
   Name=XMind
   Comment=Create and share mind maps.
   Exec=$installDirRoot/xmind8/XMind_amd64/XMind %f
   Categories=Office;
   NoDisplay=false
   MimeType=application/zip
   Terminal=false
   Icon=$installDirRoot/xmind8/XMind_amd64/configuration/org.eclipse.osgi/981/0/.cp/icons/xmind.64.png
   EOF
chown -R ${HOME//\/home\//}:${HOME//\/home\//} $installDirRoot
chown -R ${HOME//\/home\//}:${HOME//\/home\//} $HOME/.local/share/applications/xmind.desktop
}
_installXMind8

Newbie instructions for how to install XMind8 with this script:
1) Download XMind 8 zip file (which you probably already have and it is why you are here now).
2) Create an empty file $ touch xmind8Install.sh in the same directory where you have saved the xmind-8-update1-linux.zip file you have downloaded.
3) Copy-paste the contents of the above bash script into the file xmind8Install.sh
4) run $ bash xmind8Install.sh --help for usage info.
for example: $ sudo bash xmind8Install.sh xmind-8-update1-linux.zip
Answer: I've tried instructions from official site: http://www.xmind.net/m/PuDC (text instruction you can find at the bottom of page) with Ubuntu 16.04.2 (x64). Works fine!
Also, if you have fresh ubuntu installation (as I have), you probably need java to be installed: sudo apt-get install default-jre
And icon, it didn't appear out of the box, so I've downloaded png manually and specified in .desktop file, smth. like:
Icon=/opt/xmind/XMind_6_icon.png

Comment: Share detail of the solution. The link can be useful only for giving reference or more detail
Answer: I was able to get Xmind 8 update2 to install and function in Ubuntu 17.04 after installing Oracle Java 8. Xmind 8 does not seem to function with openjdk (any version).


Is there a Permesso di Soggiorno card valid for traveling around Europe?

Question: I'm going to renew my Permesso di soggiorno this April and I wanted it to be valid for traveling around Europe, for now I have Permesso di Soggiorno (Attesa Occupazione).
Comment: This question has received votes to close and move to the Expatriates site. I disagree: the documents OP asks about are issued for long-term residency, the question is not about long-term residency but about OP's right to *travel* with said documents.
Answer: I assume since you have a residence permit that you are a non-EU citizen.
From the Europa website on "Travel documents for non-EU nationals", it says:

Travel documents for non-EU nationals
Passport and visa requirements
If you are a non-EU national wishing to visit or travel within the EU, you will need a passport:

valid for at least 3 months after the date you intend to leave the EU country you are visiting,
which was issued within the previous 10 years,

and possibly a visa. You should apply for a visa from the consulate or embassy of the country you are visiting. If your visa is from a Schengen area country, it automatically allows you to travel to the other Schengen countries as well. If you have a valid residence permit from one of those Schengen countries, it is equivalent to a visa. You may need a national visa to visit non-Schengen countries.

So since you have a residence permit from Italy (Schengen country), it should be valid to travel to other Schengen countries so long as you also carry your passport.
Note that, as mentioned above, not all European countries are a member of the Schengen area, so visa requirements would be different for non-Schengen countries, (but since you've tagged the question as 'schengen' I presume you know this :) )
Comment: The three-month passport validity rule seems to apply only to non-residents when they cross an external border.
Comment: so it doesn't matter what type/kind of residence permit i have? i would still be able to visit other Schengen countries.


Is the Descending Fifths sequence also an Ascending Fourths sequence ? Who is the original source of this sequence?

Question: Can the Descending Fifths sequence also be correctly named as an Ascending Fourth's sequence ?
in major : I - IV - vii dim - iii - vi - ii - V - I
Is Johann Pachelbel (1653-1706) and his Canon in D the original source for this heavenly sequence ?
Comment: Beautiful.  The circle progression.
Comment: Your progression is :  i  -  iv  -  i      =   g  -  c  -  g
Comment: I am so new here . I just realized ggcg is a name for a musician and not a musical progression. Just saying.
Answer: Descending fifths are equivalent to ascending fourths; these intervals are the inversion of each other. Note that in the sequence of roots: C-F-B-E-A-D-G, one can either go C up to F then down to B, up to E then down to A, etc.; or one can go C down to F then Up to B, etc. Either way leads to the same set of roots (but not necessarily notes in the same octave.)
The Pachelbel Canon sequence isn't a sequence of fourths. This sequence dates back at least a century before Pachelbel. His version goes C-G-a-e-F-C-F-G. There are quite a few other similar patterns going under the name "Romanesca." The sequence starts up a fifth, up a second, up a fifth (probably dropping the actual notes an octave) and the up a second, etc. This sequence actually has hits basis in the "rule of the octave" which was just a set of patterns of chords to be played over each note of an octave. The pattern (using a slash to indicate a base not if not the root of the chord symbol) goes like this: C-G/B-a-e/G-f-C/E-F-G. The bass line drops by step from C to E then back to G. In Roman Numerals it's: I-V6-vi-iii6-IV-I6-IV-V. Alternatives are I-V6-vi-I64-IV-I6-ii6-V and others. (The I64 is just another idiomatic use of a 6-4 chord.
Some chord sequences are based on roots; some are based on bass movement; some seem irregular.
Answer: It seems to me the common wordings are:

descending fifth
descending fourth
descending third
ascending second (or step)

...in other words descending intervals except for the ascending step.
Pachelbel is famous but all of these progressions and various harmonic sequences - like Falling Thirds used in his "canon" - are too old and universal to be ascribed to one person.
Also, @ttw makes a good point to distinguish root progressions (at the basic level a two chord movement, a musical bi-gram) and harmonic sequences which typically have a two chord progression reiterated and transposed. The Pachelbel example is a harmonic sequence.


If asa Cli gets too long, it automatically gets omitted as "$". Is there no way to stop this?

Question: When saving logs in our environment, it is inconvenient to have a CLI omitted as $, so as the title suggests, I would like to prevent $ from being omitted when entering CLI or marking it, is it possible?
Comment: I don't understand what you mean. CLI and logs are different things. And the ASA does not chop log messages. Your terminal program might not "wrap to screen".
Comment: @Ricky Sorry I meant when I got the log shown on the console in teraterm.
Comment: Find where line wrap is turned off / disabled in teraterm. This isn't the ASA doing this. Your terminal application is.
Answer: I'm not sure how it will affect your log output, it probably depends on how you are collecting the logs but you can try the terminal width 0 command at various locations (config terminal or exec terminal) and see how affects the output. You can also set it much wider, like 500 and see how that works for you. It might need massaging to fit your needs.
Comment: Thx for the reply. I am using Cisco Firepower 2100 Series and 4100 Series... and there is no 'terminal width' command. Does that also work using 'terminal pager' command?
Comment: In that case, you might have to get into whatever they call the ASA command line portion of the Firepower platform. Flexconfig if I remember correctly. The Flexconfig environment is essentially the 'leftovers' of the ASA code that have not yet been migrated to the Firepower platform code so you might find the terminal width command there but whether it fixes your issue is hard to say. Cisco says some of the Flexconfig stuff is unpredictable.


Biased Ballot Theorem

Question: Classical Ballot theorem states if candidate $A$ receives $a$ votes and $B$ receives $b$ votes $(b < a)$, and assume that each candidate is equally likely to get a vote, then the probability that through the counting $A$ always leads $B$ is $(a-b)/(a+b)$. What about now we assume each time $A$ gets a vote with probability $p$ while $B$ gets a vote with probability $1-p ~(~p \neq 1/2)$? In this situation, what is the probability that through the counting $A$ always leads $B$?
Comment: What thoughts do you have on it?
Comment: I think the answer should be the same, that is (a-b)/(a+b).
Answer: I once thought that apparently the answer shouldn't be the same. It turned out to be completely wrong.
The reflection technique, as we used in the proof of Ballot theorem when $p=\frac{1}{2}$ can be adopted here too. Let $x=a-b$ and $n=a+b$.
\item Use $S^x(k)$ to denote the simple random walk starting at $x$. Here we assume the same setting as in the Ballot theorem except for the probability of $\{S^0(k+1)-S^0(k)=1\}$ is $p$ instead of $\frac{1}{2}$. \par From the definition of conditional probability, if n and x have the same parity, \begin{equation} P\left(\min_{1\le k\le n} S^0(k) > 0 \big| S^0(n)=x\right) = \frac{ P\left(\min_{1\le k\le n} S^0(k) > 0 , S^0(n)=x\right) }{P(S^0(n)=x)} .\label{3-1} \end{equation} Conditioning on $S^0(1)$, from the Markov property and time-homogeneity of $S^0(n)$, we obtain that \begin{equation}  P\left(\min_{1\le k\le n} S^0(k) > 0 , S^0(n)=x\right) = p P \left(\min_{1\le k\le n-1} S^1(k) > 0 , S^1(n-1)=x\right).   \end{equation} Use the reflection principle for simple random walk to count the path, \begin{align*} & P \left(\min_{1\le k\le n-1} S^1(k) > 0 , S^1(n-1)=x\right) \\
&= p^{a-1} q^b  ( \# \left\{ S^1(n-1)=x \right\} - \# \left\{ S^1(n-1)=-x \right\} )  \\
&=p^{a-1}q^b  (\binom{n-1}{a-1}  - \binom{n-1}{a} ) \end{align*} where $q=1-p$. Plug in (\ref{3-1}), after striaght calculation, we obtain that \begin{equation} P\left(\min_{1\le k\le n} S^0(k) > 0 \big| S^0(n)=x\right) = \frac{a-b}{a+b}. \end{equation}
Remark: Of course this only holds when $p \ne 0$. Reflection principle can be used here because we didn't use it on possibility but on counting path.
Wow!
Comment: Hi Zhengyi, thanks so much for your answer. But here the answer seems a little strange. For example, when p is sufficiently small, smaller than a positive constant C(n, x), then the probability in your answer will be non positive, which is contradictory to the fact that this can happen as long as p>0. I am not sure whether we can use reflection principle in this situation.
Comment: Dude you are awesome. I will correct in minutes.
Comment: Awesome, your method is cool!

Biased Ballot Theorem


How does MDT resolve settings specified in multiple machine roles?

Question: I have a number of machines in MDT that belong to multiple roles. Nothing fancy there. However, in role A (which applies to most machines) the MachineObjectOU is specified, and in role B (which only applies to certain machines) a different MachineObjectOU is specified because those machines need to appear somewhere different in the directory. How do I guarantee that MDT will read settings from role B? Is it the order of roles in the list in the machine properties window?
Answer: The choice is based on the order they are listed in in your Roles tab.  The first one it loads is the one that will be retained at the end of the list.
Comment: So you're saying that B cannot overwrite settings applied by A?
Answer: Based on my experience and research, Role settings are applied on a first assignment wins basis, and the order of the roles in the MDT UI has no bearing on the order in which evaluation occurs. Instead, RoleSettings (the MSSQL view that returns these settings) is queried with the following syntax:
SELECT * FROM RoleSettings WHERE ROLE IN ('List','of','Role','Names')

The results are returned and evaluated by database ID; so, if you created your roles in the following order:
Names
List
of
Role

settings specified in Names would, regardless of the order you specified, take precedence over those assigned in List, of, or Role. This seriously hampers the ability to use roles to modularize your deployment settings, unless you take especial care to pre-plan all of your roles. Even then, though, you're locked in to only ever using them in that order. As far as I can tell, there is no way to modify the ordering of results returned from RoleSettings without digging into the scripts that actually perform the query and modifying them.


What's the idea of Dirichlet's Theorem on Arithmetic Progressions proof?

Question: Dirichlet's Theorem on Arithmetic Progressions says that if $a, m$ are natural numbers such that $gcd (a,m) = 1$, then there are infinitely many prime numbers in the arithmetic progression $a + km, k \in \mathbb{N}$.
I would like to know what is the idea of the proof, and the sketch of the proof, to try to understand it. I understand the Dirichlet L-functions, to obtain the set of complex values such that the Dirichlet L-functions becomes zero, the Dirichlet character, but I heard that "Dirichlet's theorem is proved by showing that the value of the Dirichlet L-function (of a non-trivial character) at 1 is nonzero", how is that? Can someone explain how a arithmetic progression is related with a L-function?
Comment: You'd need to provide much more context. EG How much do you know? Are you familiar with complex analysis? analytical number theory?
Comment: I would say yes, but I wish an answer as easy as possible.
Answer: The sum of the reciprocals of the primes diverges, $\sum_p\frac{1}{p}=\infty$.  This can be seen using the Euler product for the Riemann zeta function (say $s>1$ real), $\zeta(s)=\prod_p\frac{1}{1-p^{-s}}$,
$$
\log\left(\zeta(s)\right)=\sum_p-\log(1-p^{-s})=\sum_{p,n}\frac{p^{-ns}}{n}=\sum_p\frac{1}{p^s}+O(1),
$$
and letting $s\to1^+$.
Dirichlet extends this by replacing $\zeta(s)$ with $L(s,\chi)=\prod_p\frac{1}{1-\chi(p)p^{-s}}$,
$$
\log(L(s,\chi))=-\sum_p\log(1-\chi(p)p^{-s})=\sum_{n,p}\frac{\chi(p)}{np^{ns}}=\sum_p\frac{\chi(p)}{p^s}+O(1),
$$
and using properties of characters to select the progression (i.e. average over all characters and "shift" $1\bmod q$ to $a\bmod q$)
$$
\frac{1}{\phi(q)}\sum_{\chi}\bar{\chi}(a)\log(L(s,\chi))=\sum_pp^{-s}\sum_{\chi}\chi(pa^{-1})+O(1)=\sum_{p\equiv a(q)}\frac{1}{p^s}+O(1).
$$
The proof goes through (letting $s\to1^+$) as long as $L(1,\chi)\neq0$ for all $\chi$.  There is a pole for the principal character $\chi_0$, and the other $L(1,\chi)$ values are finite, but we get "$\infty-\infty$" on the LHS if some of these values are zero.
The "relate arithmetic progressions to characters" question is basically orthogonality (some algebra)
$$
\begin{align*}
\sum_{\chi}\chi(a)&=
\left\{
\begin{array}{cc}
1 & \chi=\chi_0\\
0 & \text{else},\\
\end{array}
\right.
\\
\sum_{a\in(\mathbb{Z}/q\mathbb{Z})^{\times}}\chi(a)&=
\left\{
\begin{array}{cc}
1 & a\equiv1(q)\\
0 & \text{else}.\\
\end{array}
\right.
\end{align*}
$$
If you want to see some proofs, try Davenport's Multiplicative Number Theory or these somewhat concise notes I wrote once upon a time (with a  few proofs of non-vanishing of $L(1,\chi)$).

To more directly address the concerns of the question, the algebraic trick to select an arithmetic progression using characters is essentially the sum
$$
\frac{1}{\phi(q)}\sum_{\chi\bmod q}\chi(pa^{-1})=
\left\{
\begin{array}{cc}
1 & p\equiv a\bmod q\\
0 & \text{else},\\
\end{array}
\right.
$$
which is a direct consequence of the orthogonality relations above.
For example, lets consider $q=3$.  There are two characters modulo 3,
$$
\chi_0 = (0,1,1)=(\chi_0(0), \chi_0(1),\chi_0(2)), \quad \psi = (0,1,-1)=(\psi(0), \psi(1),\psi(2)),
$$
(listing the values on $0,1,2 \bmod 3$).  If you average these, they "interfere" to give
$$
\frac{1}{\phi(q)}\sum_{\chi\bmod q}\chi=\frac{1}{2}(0,2,0)=(0,1,0)
$$
which picks out the residue class $1\bmod 3$.  To pick out the residue class $2\bmod 3$ we can "shift the indices" by considering the translated characters ($x\mapsto 2^{-1}x=2x$ working $\bmod 3$)
$$
\chi_0(2x) = (0,1,1)=(\chi_0(0), \chi_0(2),\chi_0(4)), \quad \psi(2x) = (0,-1,1) =(\psi(0), \psi(2),\psi(4)).
$$
Averaging these instead, and noting $\chi(2x)=\chi(2)\chi(x)$, we get
$$
\frac{1}{\phi(q)}\sum_{\chi\bmod q}\overline{\chi}(a)\chi=\frac{1}{2}(1\cdot(0,1,1)+(-1)\cdot(0,1,-1))=(0,0,1),
$$
which picks out $2\bmod 3$.
[Note that $2\cdot2=4\equiv1\bmod 3$, i.e. $2=2^{-1}\bmod 3$, and $\chi(a^{-1})=\overline{\chi}(a)$ by multiplicativity if the bar or $a^{-1}$ is confusing.]
Comment: What I really do not understand is how do you relate a Dirichlet L-function with a congruence, let say a+kb are the numbers that are congruent to a mod b, right? How L-functions relate to this, and therefore what is the step that makes the proof done so that the progression has infinite primes.

What's the idea of Dirichlet’s Theorem on Arithmetic Progressions proof?


How do I unzip a .zip file in google cloud storage?

Question: How do I unzip a .zip file in Goolge Cloud Storage Bucket? (If we have some other tool like 'CloudBerry Explorer' for AWS, that will be great.)
Comment: Did you ever find a good solution to this?
Answer: You can use Python, e.g. from a Cloud Function:
    from google.cloud import storage
    from zipfile import ZipFile
    from zipfile import is_zipfile
    import io

    def zipextract(bucketname, zipfilename_with_path):

        storage_client = storage.Client()
        bucket = storage_client.get_bucket(bucketname)

        destination_blob_pathname = zipfilename_with_path

        blob = bucket.blob(destination_blob_pathname)
        zipbytes = io.BytesIO(blob.download_as_string())

        if is_zipfile(zipbytes):
            with ZipFile(zipbytes, 'r') as myzip:
                for contentfilename in myzip.namelist():
                    contentfile = myzip.read(contentfilename)
                    blob = bucket.blob(zipfilename_with_path + "/" + contentfilename)
                    blob.upload_from_string(contentfile)

    zipextract("mybucket", "path/file.zip") # if the file is gs://mybucket/path/file.zip

Comment: This approach downloads the entire zip file from GCS to memory, so I think it could not scale for big files
Comment: Hi Daniel, Code is not working for me, Not able to go inside if condition.
Comment: copy pasted this in a colab notebook, just needed to add auth and specify the project and it worked like a charm
Comment: Hey I have been trying with my bucket gs://frames_final/frames_final_cat.zip and the function zipextract("frames_final", "frames_final_cat.zip") but am getting an error that project was not passed to environment.
Answer: Here is some code I created to run as a Firebase Cloud Function.  It is designed to listen to files loaded into a bucket with the content-type 'application/zip' and extract them in place.
    const functions = require('firebase-functions');
    const admin = require("firebase-admin");
    const path = require('path');
    const fs = require('fs');
    const os = require('os');
    const unzip = require('unzipper')

    admin.initializeApp();

    const storage = admin.storage();

    const runtimeOpts = {
      timeoutSeconds: 540,
      memory: '2GB'
    }

    exports.unzip = functions.runWith(runtimeOpts).storage.object().onFinalize((object) => {

        return new Promise((resolve, reject) => {
            //console.log(object)
            if (object.contentType !== 'application/zip') {
              reject();
            } else {
              const bucket = firebase.storage.bucket(object.bucket)
              const remoteFile = bucket.file(object.name)
              const remoteDir = object.name.replace('.zip', '')

              console.log(`Downloading ${remoteFile}`)

              remoteFile.createReadStream()
                .on('error', err => {
                  console.error(err)
                  reject(err);
                })
                .on('response', response => {
                  // Server connected and responded with the specified status and headers.
                  //console.log(response)
                })
                .on('end', () => {
                  // The file is fully downloaded.
                  console.log("Finished downloading.")
                  resolve();
                })
                .pipe(unzip.Parse())
                .on('entry', entry => {
                  const file = bucket.file(`${remoteDir}/${entry.path}`)

                  entry.pipe(file.createWriteStream())
                  .on('error', err => {
                    console.log(err)
                    reject(err);
                  })
                  .on('finish', () => {
                    console.log(`Finsihed extracting ${remoteDir}/${entry.path}`)
                  });

                  entry.autodrain();

                });
            }
        })

    });

Comment: Thank you for your example, however I have found a serious flaw with it: You should only call entry.autodrain() if you don't consume the stream. Otherwise you will have corrupted output files. I did, until I changed the code.
Comment: I can add that you should replace firebase.storage.bucket(object.bucket) with admin.storage.bucket() as firebase is not defined
Answer: In shell, you can use the below command to unzip a compressed file
gsutil cat gs://bucket/obj.csv.gz | zcat |  gsutil cp - gs://bucket/obj.csv

Comment: Hi @Dishant, how can i use **zcat** in Google Cloud SDK tool?
`'zcat' is not recognized as an internal or external command`
Comment: @AbdurrahmanI.As of now there no functionality available in Google Cloud SDK to unzip a file. The easiest way I found, is to use this shell command
Comment: @DishantMishra If more than one files present inside zip file then How we can unzip all(we are giving one name-file.csv in destination location) like: gsutil cat gs://bucket/csv_files.zip | unzip |  gsutil cp - gs://bucket/one_file.csv. It works but we can't see multiple files. which is present inside csv_files.zip
Comment: @BhageshArora The command will not work for the multiple files zipped together as it is redirecting the output to a single file. You may have to download the file, unzip it and copy the extracted files to GCS.
You can use the below command (if JDK is installed) to directly download and unzip the files.
`gsutil cat gs://bucket/obj.zip | jar xvf /dev/stdin `
Comment: I struggled with this for making multiple process and found a simple solution. You might interest.
`gsutil cat gs://bucket/*/*/*/*.gz | zcat | gsutil cp - gs://bucket/decompressed/result.json`
Comment: this is streaming unzip,upload ? or first download the entire file first , then apply unzip finally upload back to gcs?
Answer: If you ended up having a zip file on your Google Cloud Storage bucket because you had to move large files from another server with the gsutil cp command, you could instead gzip when copying and it will be transferred in compressed format and unzippet when arriving to the bucket.
It is built in gsutil cp by using the -Z argument.
E.g.
gsutil cp -Z largefile.txt gs://bucket/largefile.txt

Comment: If I understand OP's question correctly, they are asking for a tool that will upload a zipped file and then unzip it in the bucket. `gsutil cp -Z` doesn't do that. It zips the file and leaves it zipped in the bucket. Source: https://cloud.google.com/storage/docs/gsutil/commands/cp#synchronizing-over-os-specific-file-types-such-as-symlinks-and-devices
Comment: Confirmed that this does not address the original question and it does not do the behavior described in the answer.
Answer: There is no mechanism in the GCS to unzip the files. A feature request regarding the same has already been forwarded to the Google development team.
As an alternative, you can upload the ZIP files to the GCS bucket and then download them to a persistent disk attached to a VM instance, unzip them there, and upload the unzipped files using the gsutil tool.
Comment: How do I unzip the zip files on the persistent disk attached to a VM instance?
Comment: Won't the VM instance have file size limitations?
Comment: The issue was marked as blocked, and some time later unblocked and then closed. Here's [another feature request](https://issuetracker.google.com/issues/258962925).
Answer: There are Data flow templates in google Cloud data flow which helps to Zip/unzip the files in cloud storage.Refer below screenshots.
This template stages a batch pipeline that decompresses files on Cloud Storage to a specified location. This functionality is useful when you want to use compressed data to minimize network bandwidth costs.
The pipeline automatically handles multiple compression modes during a single execution and determines the decompression mode to use based on the file extension (.bzip2, .deflate, .gz, .zip).
Pipeline requirements
The files to decompress must be in one of the following formats: Bzip2, Deflate, Gzip, Zip.
The output directory must exist prior to pipeline execution.
Comment: Only works for a single folder not when there are multiple directories within it
Answer:
Enable Dataflow API in your gcloud console
Create a temp dir in your bucket (cant use root).
Replace YOUR_REGION (e.g. europe-west6) and YOUR_BUCKET in the below command and run it with gcloud cli (presumption is gz file is at root - change if not):

gcloud dataflow jobs run unzip \
--gcs-location gs://dataflow-templates-YOUR_REGION/latest/Bulk_Decompress_GCS_Files \
--region YOUR_REGION \
--num-workers 1 \
--staging-location gs://YOUR_BUCKET/temp \
--parameters inputFilePattern=gs://YOUR_BUCKET/*.gz,outputDirectory=gs://YOUR_BUCKET/,outputFailureFile=gs://YOUR_BUCKET/decomperror.txt

Comment: Careful: this combines all files within an archive into one output file.
Answer: I'm afraid that by default in Google Cloud no program could do this..., but you can have this functionality, for example, using Python.
Universal method available on any machine where Python is installed (so also on Google Cloud):
You need to enter the following commands:
python

or if you need administrator rights:
sudo python

and then in the Python Interpreter:
>>> from zipfile import ZipFile
>>> zip_file = ZipFile('path_to_file/t.zip', 'r')
>>> zip_file.extractall('path_to_extract_folder')

and finally, press Ctrl+D to exit the Python Interpreter.
The unpacked files will be located in the location you specify (of course, if you had the appropriate permissions for these locations).
The above method works identically for Python 2 and Python 3.
Enjoy it to the fullest! :)
Comment: The point of the question was to unzip from and to Google Storage, not unzipping on a local file system. On a VM with files on a local file system you might as well just use unzip.
Comment: I tested your solution first as it seems easier than the accepted one. It failed for me at the second line when I specified a path   gs://mybucket/myfolder/myfile.zip . I don't think ZipFile can access files from the bucket directly
Comment: just to comment there is a package gcsfs which enables one to reference a gcs bucket file the same way you would the normal file system.
Comment: I don't understand why this answer gets negative points. I tried to make it as useful as possible, correct and unique compared to others answers when added this one. If someone in the comment would write me what is wrong with it, I would be grateful. Thank you!
Comment: Thank you for your comment @SylvainGantois.

Indeed, my solution assumes that we have access to the zip package within the usual folder structure.

I hope that it will be useful to some users at least, just as it was for me.
Answer: You can create a Google Cloud Function with a Cloud Storage trigger.
When a new object is created, the function will be triggered.
const functions = require("@google-cloud/functions-framework");
const {Storage} = require("@google-cloud/storage");
const unzip = require("unzip-stream");

functions.cloudEvent("gcs-unzip", async cloudEvent => {

    //console.log(JSON.stringify(cloudEvent, null, 4));

    const zipFile = cloudEvent.data;

    //console.log(JSON.stringify(file, null, 4));

    if (zipFile.contentType === "application/zip") {
        const storage = new Storage();

        async function unzipAndUploadContainedFiles() {
            await storage
                .bucket(zipFile.bucket)
                .file(zipFile.name)
                .createReadStream()
                .pipe(unzip.Parse())
                .on("entry", async function (entry) { //there could be multiple files and even a directory structure in the zip file
                    //console.log(JSON.stringify(entry, null, 4));

                    const gcsTargetFileName = zipFile.name.replace(".zip", "") + "/" + entry.path;
                    if (entry.type === "File") {
                        entry.pipe(storage.bucket(zipFile.bucket).file(gcsTargetFileName).createWriteStream());
                    }
                });
        }

        await unzipAndUploadContainedFiles().catch(err => {
            console.error(err);
        });

    } else {
        console.log("Non-zip file ignored.");
    }

});

Answer: Another fast way to do it using Python in version 3.2 or higher:
import shutil
shutil.unpack_archive('filename')

The method also allows you to indicate the destination folder:
shutil.unpack_archive('filename', 'extract_dir')

The above method works not only for zip archives, but also for tar, gztar, bztar, or xztar archives.
If you need more options look into documentation of shutil module: shutil.unpack_archive
Comment: just tested it. works smoothly. not sure why it was getting negative votes. best solution in this thread according to me
Comment: @Marc Because it doesn't work for the google cloud files in the question.
Answer: To unzip all files within a zip I used this one-liner on the cloud shell terminal:
gsutil cat gs://{bucket_name}/data.zip | for i in $(jar --list); do gsutil cat gs://{bucket_name}/data.zip | jar x $i && cat $i | gsutil cp - gs://{bucket_name}/unzipped/$i && rm ./$i; done;

Answer: Here is a python implementation with automated cloud function extractor
This method will automatically unpack any zipped file you upload your to a specified bucket.
@functions_framework.cloud_event
def unzip_zipped_files(cloud_event: CloudEvent) -> None:
    """Unzip zipped files from the a Google bucket.

    Args:
        cloud_event: An event received when a zipped file
            is uploaded to a specified bucket.
    """
    # get the event
    data = cloud_event.data

    bucket_name = data["bucket"]
    zipped_file = data["name"]
    bucket = storage.Client(project="<your-project-name-here>").bucket(bucket_name)

    # get the zipped blob using the path of the zipped file
    zipped_blob = bucket.blob(zipped_file)

    temp_file = tempfile.NamedTemporaryFile(
        delete=False, suffix="." + zipped_blob.name.split(".")[-1]
    )
    # Cloud functions offer some storage to perform downloads to
    zipped_blob.download_to_filename(temp_file.name)
    temp_file.close()

    # Now we have the local path to the zipped file (in the cloud funciton)
    zipped_blob_path = temp_file.name

    # Unpack
    shutil.unpack_archive(
        filename=zipped_blob_path,
        extract_dir="<dir-to-unpack-things-to>",
    )

    # If you have multiple files within a single zip file, get the list of files.
    unzipped_blobs_paths = os.listdir("<dir-to-unpack-things-to>")

    if unzipped_blobs_paths == []:
        raise FileNotFoundError(f"No unzipped files found in {zipped_file}")

    # upload them to another bucket (in the same project)
    bucket = storage.Client(project="<your-project-here>").bucket("Abulubad-unzipped")
    for blob_path in unzipped_blobs_paths:
        blob = bucket.blob(blob_path)
        blob.upload_from_filename(blob_path)

After setting this function in your directory, all you have to do after that is follow some steps in the Deploying the function section using the Cloud function docs and you will have the cloud function up and running.
let me know if you face any issues :)


Ubuntu fails to boot; stuck at initramfs

Question: I'm a complete novice at Linux. I put my session on suspend, but when I tried to start it back up, it put me at the GRUB boot menu. After selecting Ubuntu, it put me in an initramfs prompt. I've tried looking for solutions but those required me to use live media or boot into Windows, neither of which I can do. My laptop is a Dell Inspiron 1420 and I have Ubuntu 15.10. What do I do? Thanks in advance.
Answer: Unfortunately, if your Ubuntu system won't boot, and you don't have any live media at hand, there isn't really anything you can do.

However, you could try booting into "Recovery mode" in GRUB (It's under Advanced Options), and see if that helps any.
If it doesn't, you'll need to get a hold of some live media. Then, you can reinstall Ubuntu (if the problem doesn't go away), or install Boot Repair (an application that fixes GRUB).


Regarding so and very

Question: As we use so before adjective like "the movie is so interesting," but can I say negative way like "the movie is not so interesting" means I want to say someone the movie not good?
Comment: Yes, you can say that. For future questions, you may prefer to ask on our sister site, [ELL.se], which is dedicated to helping people learn English as a foreign language. Despite its name, this site is for more academic questions of English than practical ones.
Answer: Yes, this is perfectly acceptable.

"That movie was so boring!"
  "Really?  I thought it was not so bad."
"This dress looks so tight on you.  Isn't it uncomfortable?"
  "No, it's not so uncomfortable."
Answer: You are almost correct, the problem is

so not
  not so

are not commutative.

The movie is so interesting.
the movie has a high degree of being interesting.
The movie is not so interesting.
the movie has a low degree of being interesting.
The movie is so not interesting.
  The movie is so uninteresting.
the movie has a high degree of being uninteresting.

Regarding so and very


How can Binance Smart Chain hold coins from different blockchains, like ETH?

Question: Sorry for the n00b question... So, I use MetaMask to hold a few coins. In my MetaMask BSC account, I also have some ETH coins. Are my coins actually represented in the original Ethereum blockchain with a specific Ethereum address with the same ETH amount? How are BSC and Ethereum connected in order to support these functions?
Answer: Your question errs towards a more general question: how can non native tokens be contained on a different network?
In the case of binance smart chain or BSC; this smart chain is in fact a hard fork of Ethereum - as such, whilst the consensus mechanism for the chain differs, the underlying code representing tokens has a similar enough architecture, allowing the chain to host 'ERC20' tokens (including Ethereum).
In other cases (think, BTC to ETH) where the blockchain itself is different, tokens are 'wrapped' so as to allow their existence on a different chain. This essentially means 1BTC (for example) is 'wrapped' in a little packet of code which allows nodes and miners on the Ethereum chain to hold, transfer and receive the wrapped tokens.
Comment: Thanks for the answer. So, if the BSC is a hard fork of Ethereum, does that mean that BSC maintains a different ledger than the actual Ethereum, or it maintains a branch extension of the actual Ethereum ledger, or it maintains a totally new ledger instance?
Comment: After the fork, the BSC chain grows into a different ledger as time goes on


Is it acceptable to assume there will be no 'walk' in coordinates transformed back and forth between two datums?

Question: Given that you use the same datum transformation, you should end up with the same coordinate regardless of how many times you convert between to datums.  Is this a correct assumption?  Is this applicable for both equation-based and grid-based transformations?  For example: Convert NAD27 to NAD83 via NADCON then from those NAD83 to NAD27 via NADCON, and again, etc.
Comment: Theoretically yes but in a computer world with limited accuracy of floating point calculations not even if the formulas were perfect, and naturally they are not.
Comment: There's almost always some rounding in a floating point calculation; a float, double or decimal can only store a finite number of digits and the rest are lost... it's in the order of nanometres usually but even a nanometre often enough can result in vertices (points) *walking* all over the place. It's best to only project **when you absolutely have to**. Note: this does not apply as much to *project on the fly* systems, the storage is in the datasets natural CRS and the display is in the screen CRS but really the projection is only done once: on edit/store, unmodified features are unchanged.
Answer: Using NADCON as transformation method between Nad27<>Nad83 is accurate when the map scale is 1:1200 or smaller.
Accuracy and uncertainty [Reference1][Reference2]
The following statement is from the release notes of NADCON Version 2.1, October 1993:
"The accuracy of the transformation should be viewed with some caution. At the 67 percent confidence level, this method introduces approximately 0.15 m uncertainty within the coterminous United States, 0.50 m uncertainty within Alaska, 0.20 m uncertainty within Hawaii, and 0.50 m uncertainty within Puerto Rico and the Virgin Islands. In areas of sparse geodetic data coverage, NADCON may yield less accurate results but seldom in excess of 1.0 m. Transformations between NAD83 and the States/Regions with High Accuracy Reference Networks (HARN) introduce approximately 0.05 m uncertainty. Transformations between old datums (NAD27, Old Hawaiian, Puerto Rico, etc.) and HARN could combine uncertainties (that is, NAD27 to HARN equals 0.15 m + 0.05 m = 0.20 m). In near offshore regions, results will be less accurate but seldom in excess of 5.0 m. Farther offshore, NAD27 was undefined. Therefore, the NADCON computed transformations are extrapolations and no accuracy can be stated."
Conclusion
In general, Any transformation procedure has an accuracy range and of course when transferring (to & back) many times you will have less accuracy as a result of the computations and the iterations. From the numbers above and from NADCON methodology, the accuracy is different.
If it's acceptable or not? that depends on how much accuracy you want? and depends on the area, and the scale.
Comment: I believe I am more interested in the relative accuracy of the converted point(s) back to the original point.  Those should stay the same right, other that rounding and data precision problems others stated.
Comment: @Rex Technically yes, the values should be the same at least with three digits rounding


I have a mobile app that produces lots of data and I wish to make it available to everyone

Question: My app produces geo-spatial data which I can host on my servers, but I also wish to give this data away to the open data community, does any one know of a hosting organization where I can create a website, and offer the data and incur no expenses on my part?
Comment: why not you make a website from any freelance website. You will find a lot out there.
Answer: Have you looked at Freebase?  It looks like it might accept datasets, although you wouldn't build a website there; the data would be accessible through their existing site.
Comment: This from a freebase expert: "This is just my personal opinion, but I'd say that pothole data is probably a little more fine-grained than Freebase traditionally deals with, but probably not completely out of bounds."


tfs does not have "Mock debug" configuration

Question: I am trying to build a solution that has 3 projects. The solution configuration is Debug| Win32. On the solution configuration properties, for the projects:
Project      Configuration   Platform
1st project: Mock Debug       Win32
2nd Project: Debug            Win32
and same goes for third.The build is failing because of the First project with Configuration Mock Debug.
The error throws LINK : fatal error LNK1104: cannot open file $(Configuration)....
When I build on VS2012 it builds fine. It creates a folder "Mock Debug" and places the lib there. And VS can find the lib. No problem, build successful.
But in tfs I cannot specify configuration "Mock debug" so it does not create the folder "Mock Debug" and does not place the .lib. there. I cannot change any of the solution configuration or the project property. Is there any way to specify exact configurations for the individual projects build under the solution in the tfs build definition. I know I can pass MsBuild Argument in build definito but I am not sure if that will work. I tried specifying "Mock Debug" configurations manually, under "items to build" and "configuration to build". But it does not find "Mock Debug" configuration. I found out team build does override $OutDir specified in the project and places all binaries somewhere else hence it cannot find the .lib file. But the problem is The Folder specified by $(Configuration) "Mock Debug" is not created. I think I am missing something here....any suggestions.
Answer: Just put such a configuration or dll in the following path on the building machine
"C:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\PublicAssemblies"
Note: you many need change the bath depend on the VS version you are using.


Loop quantum gravity

Question: Is Loop Quantum Gravity trying to bring quantum mechanics from it's principles? Or is it taking ideas from quantum mechanics and merging them with GR to find a theory of quantum gravity?
Comment: LQG tries to quantize gravity whilst keeping with the main tenet of GR, that is, background independence (as opposed to string theory). But it isn't really 'adding ideas from quantum theory to GR' or vice-versa.
Answer: LQG in principle is trying to discuss gravity as a quantum field theory from a geometric perspective. It is not a "theory of everything" so it does not want to explain qm.
It evolved into a theory which is capable of discussing the evolution/interactions of a small (planck sized) chunk of space  and also apply its principles to early universe physics (loop quantum cosmology, LQC).
If we have a working and renormalizable theory of quantum gravity then we can merge it with the standard model.
LQG is currently not trying to be such a theory, as quantizing gravity in itself is already hard enough of a problem!
Answer: LQG came from work on spin networks, which posed a simple question: Suppose you were unaware of space-time and looked at networks of interacting particles with spin, would space-time or something similarly arise naturally from their description?
Penrose only applied QM principles, he did not modify QM and did not bring in any GTR; rather he hoped that he could derive GTR-like results from his model. In this sense, LQG is much more natural than string theory which "generalises" QM. On the downside, not all the desired GTR-like results have yet been derived.

Loop quantum gravity


Can I create a forward for the old link?

Question: I updated the initiatives on our website to say 2016 and now all the old links  to our current initiatives that were posted or shared (web, email, social etc.) in the last year is now broken. How cab I remedy this? Can I create a forward for the old link? Thank you!
Answer: Well, there are a variety of ways to make this happen. To give you the absolute best answer, you'd really need to give more information on your EE setup in general. It would've helped if you had given an example of the URL you need redirected as well. Here is a simple solution.
You'll need to edit your .htaccess file. It lives in the web root of your server. Warning: If you are not a developer, it is recommended that you get someone more tech savvy to do this for you. One mistake in this file will render your website unavailable until it is fixed.
If you have an example URL, such as www.example.com/initiatives/2015/, and you want to permanently redirect it to www.example.com/initiatives/2016/, under most cases a RedirectMatch rule will work. Here's an example:
RedirectMatch 301 (?i)^/initiatives/2015/?$ http://www.example.com/initiatives/2016/

This will match URN's that match /initiatives/2015/ and permanently redirect them to http://www.example.com/initiatives/2016/ . The match will be permanent (301) and will be case-insensitive ( (?i), so /INITiatives/2015/ would also redirect). You can add this line at the end of your .htaccess file.
Comment: Or use Detour Pro https://devot-ee.com/add-ons/detour-pro


Is there any particular difference between "moving" and "poignant"?

Question: Both are defined as "making you feel strong feelings of sadness".
Comment: What did your own research indicate ?
Answer: Have a look at the alternate definitions of the words. Even when the use case isn't appropriate, they often colour the meaning of the one your looking at.
I would say that "moving" has no implication that the feelings are sad. Unless there has been further context given to imply such emotions, I wouldn't assume it. 'Moving' often evokes a response, e.g. being moved to action. Something 'poignant'; however, may be of intellectual interest in and of itself but not evoke emotions or action.
I see 'moving' as generally positive. If I find a piece of music moving then it may be uplifting. Strong sadness is possible, but only one possible emotion.


Does sound take form of the medium it travels through?

Question: I've always wondered how striking a tuning fork and holding the Struck fork next to a cylindrical body with an adjustable length can yield an ideal length of that body which produces the loudest sound.
I saw this in a Julius Sumner Miller lesson and was curious about why a specific length yielded a specific loudness of a given frequency. His attitude of "letting you think about that" raised a couple of questions.
1. How does sound travel through a hollow body/vessel? Is there an ideal face shape for that vessel that sound travels about best? For instance would sound travel more efficiently through a cylindrical vessel than through a vessel with more edges?
2. In addition what makes the sound the loudest from the audiences perspective? Is it possible that the frequencies traveling through this body are intercepting directly at the point where the end of a certain point of the face the body meets atmospheric air?
ex. For example, if the frequencies from the tuning fork travelled through the body, and met at their respective points on the face of the the vessel where it meets atmospheric air, there's a specific length of that adjustable vessel that would allow for the frequency to intercept with itself at that exact point.
If any of these questions could be answered that would be great. And if my last question is even comprehendible or can be further educated with some critiques or enlightenment of my knowledge of sound, that would be greatly appreciated. Thank you.
Comment: The general answer to your question is related to "standing waves in tubes". If you look it up you will find out how the length of the tube is related to the frequency.  Unfortunately I don't undertsand your other questions so I cannot answer them.
Answer: Hollow body: sound travels by bending the shell, in most cases you imagine. Especially if wavelength is significantly longer than the shell thickness. Best shape is the one with significant stiffness, that is usually provided by two axis bending, like a sphere or a saddle. Flat shape is worse because it is usually poorly supported and tension changes along the body, making it harder for the sound to move through all sections of the body with different stifnesses. Each body's part can be imagined as a mass-spring system. Each body part must have the same resonant frequency for a single wave to travel further. Flat body almost always is tensioned unevenly, making spring-mass model have different resonating frequency, thus no particular frequency can travel this system well. Cylinder is a bit better than flat sheet but worse than a sphere. Any edges are worse than even a flat sheet. Just imagine the object as a thoudand tiny mass on springs, and that each is a filter to one frequency. Edges would be much more stiff than the surroundings for example, making them pass very different frequencies.
Sound attenuation: sound can be seen as power, and more power you add, more sound you get, just as with electricity. Nothing stops you from just using lots of power to make much louder noise. Another point is human's ear sensitivity to particular frequency. We can hear 20hz-20khz. But our sensitivity is stronger within 300hz-3khz. And maximum sensitivity is about 1khz. So spending same power at 1khz than at 10khz, a human will hear the sound much louder, about 10 to 100 times, depending on age. Older people decrease in high frequency sound sensitivity. Depending on transfer medium you can also lose some frequency. In particular high frequencies are lost faster in almost all cases. If your source of sound is far away, high frequencies will attenuate much more. 100Khz drops in power 10 times every few meters for example. So if a bat uses echolocation at this frequencies, it cant see further than a few dozen meters. On the other hand whales use very low frequencies for their echolocation, and their sound goes without much attenuation for many kilometers. Sound does get lost on a larger area, but it power is delivered to the target almost fully. If a bat would try to echolocate something a kilometer away, its sound power will simply be lost as heat into the air, with next to nothing reaching the target. Same rules applie to almost all barriers that force sound to convert it power to heat. Same applies to bone conductivity headphones, they lose high frequency in the bone as heat. But they are bad with the bass to begin with, so it cancels out. Some rough numbers, 1w of sound power is similar to a person screaming, so overheating from sound is very unlikely. Unless ultrasound with many kw of power is used, like in ultrasound plastic sealers. Regarding mundane conditions, ear and few meters of air - there is no significant loss of sound power, so there is no significant change in what frequencies pass unaffected either. They all do about the same.
TLDR: each sound frequency carries a bit of power. Any obstacle is more likely to turn to heat high frequency sound easier. Sound frequencies are not interacting with each other. Sound travels with the maximum speed it can all the time. Springy objects may pass one specific frequency but block all other. For sound going through springy objects imagine each part of object as a spring and mass that can wobble. Springy objects with different resonant frequencies along it body will end up blocking all frequencies. High quality ringers have all of their shell parts designed to pass the same frequency.
p.s. the title - 1khz sound wavelength is 0.3m in air or 5m in metal. Sound takes atleast this much space. Sound goes as full volume if it can. It can also travel as surface wave on thinner object, like string or a flat sheet. In springy object with surface wave spring-mass analogy is better than imagining that sound is a blob 5m in diameter.


IOSharedDataQueue example

Question: Where can i found sample code for using IOSharedDataQueue ( i want to send data from user-space to kernel-space)?
Answer: sending sporadic data betwixt userland and kernelspace is generally done via IOUserClient http://developer.apple.com/library/mac/#samplecode/SimpleUserClient/Introduction/Intro.html
IOSharedDataQueue is a bigger hammer and would be to run a constant stream of data, like if you needed to push / pull audio or video data in realtime.
if you just need to get messages or notifications to and from the kernel, use a userClient...

IOSharedDataQueue example


Can Linux OS Boot off MBR in Native UEFI?

Question: While UEFI & GPT go together, I was wondering if Linux can be instilled and boot off MBR Partition type while in Native UEFI Mode?
Comment: I thought the whole idea behind UEFI was that you couldn't boot off the MBR, because you now have a new and shiny EFI partition that is _much_ better.
Comment: An MBR is the first sector of the disk, which (on BIOS-based computers) holds both a first-stage boot loader and a partition table. Given the context of the question, it sounds as if the question is focusing on the partition table aspect of MBR, not the boot loader it contains. If I'm mistaken, I ask pat2015 to clarify.
Answer: Linux can certainly boot off an MBR disk in EFI mode. The trouble is that this type of configuration is poorly tested, and you may have problems getting your boot loader registered with the EFI. You might need to name your boot loader EFI/BOOT/bootx64.efi and rely on the EFI using this fallback filename.
Also, most Linux distributions' installation programs won't make it easy to set up this sort of configuration; you may need to install to GPT and convert that to MBR, or install in BIOS mode and then install an EFI boot loader after the fact.
All of which brings up the question: WHY? MBR partitioning offers precious few advantages over GPT. The main reason I can think of for favoring MBR is that it's supported by older OSes (DOS, BeOS, OS/2, etc.) -- but those OSes all boot exclusively in BIOS mode, so if you're dual-booting with one of them, you'll be better off installing Linux in BIOS mode, too, because boot-mode switching is pretty awkward. To be sure, it can be done, and there are tools that can help, but without understanding the reason for wanting to do what you're suggesting, it's hard to advise on what the best course of action would be.
Comment: I was wondering if GPT is a mandate for EFI. It seems that Windows 7 x64 or Win 8 does not install on MBR disk at all in EFI.   While you will have to forgo   benefits of GPT just if such a config was technically possible under Linux. Thanks Rod for the clarity.
Answer: Linux supports BIOS+MBR, BIOS+GPT, UEFI+MBR and UEFI+GPT.
Today, I was planning to install Ubuntu in native UEFI with GPT. But I forgot to reformat my SSD and installed Ubuntu in native UEFI mode with MBR partition table. As you can see from the picture here.

I can't think of any reason to use MBR in native UEFI. And I need to reinstall my Ubuntu system.


What is Lord Vishnu's favourite food?

Question: I am gonna install Lord Vishnu's deity. So I would like to know what is Lord Vishnu's favourite food.
Comment: Bhakti is his favorite food, he can never get enough of it.
Comment: Hello! There is no urgency that you should accept the very first answer you get. Wait for some time for other answers to come and chose the best answer which you receive. You can wait for some certain time say two days. Why because some users refrain from writing answers if there is an accepted answers already. So, wait for some time and then accept the answer. And don't forget to accept the best answer you get.
Comment: I am not answering, because I am just posting a link . from https://en.wikipedia.org/wiki/Sudama  " He leaves with nothing but some beaten rice tied in a cloth as a present. He remembers that beaten rice is Krishna's favorite and decided to give this as a gift to the Lord."
Comment: He likes yellow food most. He will acept whatever you give him as long as it is with passion and beief.
Answer: There is nothing like not favourite item to the Lord. Every item is a favourite to Him. The most important thing the Lord sees in us is devotion while accepting an offering. In Bhagavad Gita, He says this explicitly.

पत्रं पुष्पं फलं तोयं यो मे भक्त्या प्रयच्छति |
  तद्-अहं भक्त्य्-उपहृतम्-अश्नामि प्रयतात्मनः || ९.२६ ||
patraṃ puṣpaṃ phalaṃ toyaṃ yo me bhaktyā prayacchati |
  tad-ahaṃ bhakty-upahṛtam-aśnāmi prayatātmanaḥ || 9.26 ||
Meaning: Whoever offers to Me with devotion a leaf, a flower, a fruit or some water, I accept this offering made with devotion by one who is pure of heart.
यत्करोषि यदश्नासि यज्जुहोषि ददासि यत् |
  यत्तपस्यसि कौन्तेय तत्कुरुष्व मदर्पणम् || 27||
yat-karoṣi yad-aśnāsi yaj-juhoṣi dadāsi yat |
  yat-tapasyasi kaunteya tat-kuruṣva mad-arpaṇam || 27 ||
Meaning: Whatever you do, whatever you eat, whatever you offer in sacrifice, whatever you give away, whatever austerity you practice, O Kaunteya, do that as an offering to Me.

So, you can offer anything to Lord Vishnu with a pure heart and devotion. What ever you do, what ever you eat, don't forget to offer it to the Lord.
But if you are very much interested in the food item which is favourite to Lord Vishnu, there is a big list for this. Tirumala Tirupati Devasthanam is one of the world famous temples in the world. The main deity here is Lord Venkateshwara. Many items are offered to the Lord here.
Quoting from this answer of mine,

Lord Venkateshwara is known as naivedya priya meaning who is fond of offerings. Actually, Laddu is not the only prasadam at Tirumala. Besides this many prasadam like different types of rice offerings like pulihora, curd rice, different types of pongali, ravva kesari, butter, curd etc., are offered. In addition to these prasadams, kadambam, dosa made with black gram, ksheerannam, vada, rice made with pepper etc are offered to the lord at different timings starting from suprabhata seva performed early in the morning..... Later many prasadams were introduced at lord's temple like appam, manoharapadi, atirasam, sukheeyam etc.

This is from Tirumala Tirupati devasthanam. In Puri Jagannatha temple wide variety of prasadams are offered. This means they are also favourite items of the Lord.
So, there is a huge list of food items you can choose from. But don't forget... offering with devotion is important.
Answer: Lord Vishnu loves food items that are yellow in colour.

Yellow lentils,jaggery, yellow ladoo are considered the favourite foods of Lord Vishnu. Lord Vishnu likes amla gooseberries too.

Devotees offer him yellow lentils mixed with jaggery in order to please him. Even yellow laddoos are commonly offered to Vishnu.
Source: https://www.newsgram.com/guide-to-hindu-gods-favourite-food-items-find-out/
Comment: You should cite sources.
Comment: Also Semolina Pudding. We prepared this for SatyaNarayan Puja.

What is Lord Vishnu's favourite food?


Why is quantum physics needed to explain photosynthesis?

Question: Why is quantum physics needed to explain photosynthesis?
In what aspect does the corresponding classical theories for photosynthesis fail?
Comment: Maybe the bigger and more relevant question is how, instead of why quantum physics is being used to explain photosynthesis.
Answer: The absorption of light is a quantum process.
Here is an article from Nature (2004) that addresses the question:
http://sitemason.vanderbilt.edu/files/iqLVYI/Fleming 2004 Nature 431 256.pdf
Answer: Well, photosynthesis has to do with the absorption of photons to break/make certain bonds. The most classical you can get with this is Bohr's model, nothing prior to that explains absorption of light. Bohr's model is kind of an extremely basic type of quantum mechanics, and anyways it does not work for multielectronic species. Bonds become impossible to analyse here.
Normal QM/molecular orbital theory, on the other hand, deal with the nature of the electrons, even when they are in bonds. So it explains the process pretty well.
So it's not that some classical theory failed, it's that there was no way to classically explain photosynthesis further than "the bond absorbs light".  Why does the bond absorb light? Because it can{*}.
Classical theories need not fail in every aspect :)
*Insert appropriate James Bond joke here
Answer: The article Arnold links to is well worth a read, but in addition to that, recently there has been a lot of interest in the role of quantum entanglement and coherence in photosynthesis. If you've recently come across articles about quantum physics and photosynthesis it's probably this aspect that was being described.
I don't know of any definitive review of this area, but Googling for "photosynthesis entanglement" or better still "photosynthesis entanglement site:arxiv.org" finds lots of articles.
Answer: This first began after observations that plants can maintain quantum entanglement even at room temperatures.
This link explains very well your question (it contains the research done in this new field):
Quantum Photosynthesis.
Answer: Plants harvest light with near perfect efficiency, but this is impossible under classical physics. Along the way to the photosynthzing core, photons should collide with other particles, but they don't. A photon reaching the core is as likely to succeed as you sprinting through a dense forest blindfolded trying to get to the center of the forest without hitting any trees. Plants are engaged in a kind of miracle. The plant puts the photon into a state of quantam superposition, multiplying it by every route the photon could take. It's like when you are running through the forest being multiplied into the billions of possible routes. If any one of the possible routes were observed hitting a tree,the Super position would collapse, and that would be your final outcome. A plant simply refuses to view any of these casualties.


DIY fresh air intake

Question: I live in a concrete block home in SE Florida. The air in the house stinks and I am well aware of indoor pollution. The house is 2 years old and we have lived in it one year. The first year the house was vacant BUT the AC (2.5 T) was kept on. We AC 1800 sq ft with insulated ductwork in the attic. I talked to 2 contractors. They want to stick an outdoor duct into the supply and leave it open. Yea right. I want an electronic damper that I can open say 12 to 4 AM (lower temp and humidity) I want them to exhaust the air from the return located at the other end of the house. They look at me as though I have 3 heads. They want to bring in air all the time and not exhaust any. I say not possible with tight CCB home and few windows. How do I size and buy the necessary stuff so I can hire some one to do the labor. Am 71 and tired of cleaning up other peoples messes!
Answer: I use a charcoal filter ahead of the regular filter. My wife has a nose that can smell anything even a football field away. They work great, I buy mine at Home Depot or lowes for around $10.00. Look for the WEB Absorber, ask an attendant in the heating/ ac section. It is a cut to size and comes in  20x25 size. I only had to cut the plastic piece once and reuse with each change. Mine last 6 months.
Comment: The climate in SE Florida is so mild that an energy recovery ventilator would seem to be overkill. I would try the activated carbon filter first. Just be sure it does not restrict the air flow too much. What kind of filter do you use in the central a/c unit? What kind of a/c unit do you have?
Answer: Barb-
I live in your area in the same kind of house. Even from 12 to 4 am, the humidity is too much. With your plan, you will rust out the inside of your air conditioner in a year. Not to mention the energy costs you'll sink in to running your AC during those hours, plus the extra hours during the day you'll need to run it to pull all that humidity out.
What you want instead is an energy recovery ventilator. These are an improved version of air to air heat exchangers used up north, except that they keep the humidity out, too.
Comment: Thank you longneck. Actually, I had a Bryant recovery ventilator in Wi. It only took about 20 minutes to turn the air over. Talked to Bryant and they no longer recommend them down here. What I had used the return air to condition the incoming air. If it got down to zero, water built up in the ductwork as well. It migrated to the lowest point! It turned cooler down here and without AC, the smell in my house went away. "Dirty sock syndrome"!  Am installing REME Halo. Mold on coil is bad. This will add both UV & hydro peroxides to ductwork. Cleaner air w/out air intake. Reviews are very good.
Answer: Exhaust vents in the kitchen and bathroom are plenty for a make up air system. You really don't need a lot of air if used 100% of the time and there is less to go wrong. Having the exhaust in a specific location may help that area but remember the kitchen and bathroom vents will allow air to flow out no matter how tight the house was built. If you are willing to pay for automatic dampers and timers and the maintenance on them you should get what you want. Just remember it may be your mess if you don't consider the advice of a professional installer at some level. I live close to the ocean and it is funny there is almost never fog at noon but almost always at midnight. Fog= damp air.

DIY fresh air intake


Searching for contacts using a list of first/last names

Question: I've got a list of names that I need to find the contact profiles for. I only have the first and last name, is there a way to search for a batch of people and show up as a list view rather than searching one by one? I've tried search builder and custom seacrch but neither of them seem to have the functionality to search for multiple different names.
Answer: Welcome to CiviCRM stack exchange. I don't think there is anything built in. If its a lot of people you have in a spreadsheet, I'd export all the conatcts with contact ids to a spreadsheet and than match these the the people on your list. Delete the rest of the conatacts from the spreadsheet. Then import those contacts as an update (not changing anything), adding them to a new group. Then you can use that group to select the people on your list.
Comment: or you could just try the 'import' set to Match, and track your imports by adding to a Group, as Mick suggests, so you can delete any new ones that get created which you don't want. (Adv Search lets you filter for 'Created' today)


Disassembler for Renesas RX62 micro

Question: Does anybody know a free disassembler tool for decoding a Renesas RX62 micrcocontroller binary file? There had been www.onlinedisassembler.com, but this site is down and the new beta.onlinedisassembler.com does not integrate the RX type for disassembling. It would be fine too if it would be an offline tool, for sure...
Answer: Renesas provides a GNU toolchain for the RX series which likely includes objdump tool which should be able to disassemble code for RX.

Disassembler for Renesas RX62 micro


hitting time of the first quadrant for a 2-d random walk

Question: Suppose $(S_n)_{n=1}^{\infty}$ is a simple random walk in $\mathbb{R}^2$.  Let $\tau_{(a,b)}$ be the hitting of the first quadrant when $S_0 = (a,b)$.  Is there a way to compute or estimate the distribution of $\tau_{(a,b)}$?
Answer: Asymptotic estimates for $P(\tau_{a,b}>n)$ as $n\to \infty$ can be obtained using the approach from http://arxiv.org/abs/1110.1254 (Random walks in cones). The results are valid for general random walks.
1) First we need to find the corresponding  asymptotics for $\mathbf P(\tau^{BM}_{a,b}>t)$  for the Brownian motion. For that we can use paper Brownian motion in cones (doi:10.1007/s004400050111) which says that $P(\tau^{BM}_{a,b}>t)\sim \varkappa h(x,y)t^{-p}$ for a harmonic function  $h(x,y)$ and some constant $p$. Harmonic function should be greater than $0$ on the continuation cone C and equal to 0 on the boundaries. Continuation cone $C$ in your question is a union of the 2nd, the 3rd and  the 4th quadrant.   For your question the required harmonic function will be $h(r,\phi) = r^{2/3}cos (\frac{2}{3}\phi-\frac{5\pi}{6}) $ in polar coordinates and p=1/3. Hence, $P(\tau^{BM}_{a,b}>t)\sim \varkappa h(x,y)t^{-1/3}$, as $t\to\infty$. Constant $\varkappa$ can be found in Corollary 1 of  Brownian motion in cones (doi:10.1007/s004400050111)
2) Then you can use the main results of the above paper (Random walks in cones) to show that  $P(\tau_{a,b}>n)\sim \varkappa V(a,b)n^{-1/3}, n\to\infty$ for the function $V(x,y)$ which is harmonic for the killed random walk. We know that
$V(a,b)\sim h(a,b)$ when $a$ and $b$ are large and far away from the boundary of the cone $C$.
There is also a recent paper discussing your question http://arxiv.org/abs/1511.02111 This paper also gives asymptotics for $P(\tau_{0,0}>n)$, see Remark 2 on page 5.


Setup a budget home studio

Question: I decided to have a home budget studio and i wanna ask because i have a lot of questions.
I have a laptop, mackie cr3 monitors, behringer xenyx 502, BM700 condenser mic, behringer headphones and Audio-M keystation 32 midi.
The problem is : audio interface doesn't have usb to connect to laptop so i need to buy a usb audio interface again money so maybe I'll return it back and I'll buy an audio interface with usb ? This was 1st question.
I bought 2 TRS cables to connect the monitors to audio interface for a better sound but i didn't got the sound . So i checked in the drivers is not showing that i connected the audio interface. Yes i was rushing and i bought usb audio interface also behringer uca202 i think and i got very very low sound to monitors and very low sound from mic.
I'm really confused of a lot of videos watching in YouTube and no one is showing from a to z everything all the connections all types of cables .
PLEASE can anyone help me to make it works .
Thank you!
Comment: I suggest two related things: First start with just two pieces of gear and get them connected and talking. If you have headphones, then I would plug the headphones into the mixer and the see if you can get the microphone and mixer working together. Don't try to plug it all in at once and figure out how it all works as one big thing. Second, do the same for this question. Asking how to do it all at once is considered too broad here. Instead, edit this down to just connecting two pieces of gear. "How do I connect the mic to the mixer?" is a good question - just one example.
Comment: @Tim Because it's not an answer, it's a suggestion on how to change the question to make it appropriate for the site. As it is, the question is too broad. I just like to give more than 9 minutes to read and react to my comment before I VTC.
Comment: @ToddWilcox - why not proffer this comment in an answer?
Comment: 1) Is that a midi controller (the keyboard)? if so it will not make sound on its own it will only control a midi device.  2) does that condenser mic need phantom power (consult the manual) and is your mixer capable of providing the 48v power (phantom power)?
Comment: Where did you buy all this from? If (hopefully) all from one place, call them and ask for some technical advice; they're usually happy to help, because if you need replacement or more equipment, you'll buy from them.
Comment: I'd start [here](https://sound.stackexchange.com/questions/44184/buzzing-hissing-issues/44185#44185) for that BM-700. They don't even come with the right cable to set up phantom power...
Answer: OK, here's a quick rundown on what you need (and don't need).

Laptop - Do you have a Mac, or a PC? You're going to need DAW software of some sort anyway. Look around - you can get free software out there (worth every penny :/ ).
Keyboard - You have the Keystation 32 Midi. This can plug directly into your laptop, and the DAW software should see it.
Microphone - The BM-700 should have two cables with it - a standard XLR cable, and an XLR-USB cable. If you use the USB cable, it will plug direct into your laptop (and the mic will pull the power it needs from the laptop). If you want to use the XLR cable, the Behringer Xenyx 502 does provide provide phantom power, which this microphone requires in order to work.
Monitors - The CR3 monitors come with an RCA-3.5mm cable. Use that - plug one end into the laptop, and the other end into the main monitor.

Stuff you don't need:

The mixer. Unless you want to mix different instruments live, you can do without this altogether.
The Audio Interface. This is only needed to bring analogue instruments and mics into the DAW. You're not doing that (the keyboard is digital, and so is the mic if you use the USB cable). If you play guitar, you do need an audio interface. But... not that one.
The TRS cables. The outputs from the mixer are TS 1/4" (not TRS), and you're not using the mixer anyway... The RCA inputs to the monitors are more than sufficient for your needs at the moment.
Comment: I actually bought one to be able to answer the myriad questions we see about it [wasn't going to break the bank]. It works, once you get phantom to it, but it's not going to win any awards ;)
Comment: Unless some are packaged differently (& there appear to be a million versions of the BM-700/800/8000 around which all look about the same) then there's no regular XLR-XLR or USB cable in the box, just a totally useless XLR->mini TRS.
Comment: @Tetsujin: You may be correct. I just used a statistic of one sample from a well known shopping site. It's not a mic I would use, so can't comment further.

Setup a budget home studio