we know that electrons in superconductor are coupled somehow ()   creating quasi-particles called cooper pairs which are Bosons and going to ground state ( do not obey Pauli exclusion anymore)  and that happen after this?.. how can be charge was cared without any dissipation?
I read in a book &quot;Physics - Resnik and Halliday&quot; the explanation of Type-I Superconductors {cold ones} that:  The Electrons that make up current at super-cool temperatures move in coordinated pairs. One of the electrons in a pair may electrically distort the molecular structure of the superconducting material as it moves through, creating  nearby short-lived regions of positive charge.the other electron in the the pair may be attracted to the positive spot. According to the theory the coordination would prevent them from colliding with the molecules of the material and thus would eliminate electrical resistance  Is this the only explanation or can somebody give me a more intuitive explanation that also takes into the problem of defect scattering as in the case of resistance and also explains the Type-II superconductors {hot ones} P.S. What are &quot;coordinated pairs&quot;?
Evaluating the nested radical $ \sqrt{1 + 2 \sqrt{1 + 3 \sqrt{1 + \cdots}}} $. How does one prove the following limit? $$   \lim_{n \to \infty}   \sqrt{1 + 2 \sqrt{1 + 3 \sqrt{1 + \cdots \sqrt{1 + (n - 1) \sqrt{1 + n}}}}} = 3. $$ Does Change Data Capture (CDC) work in a SQL Server 2012 AlwaysOn Failover Cluster Instances setup? Does  work in a  setup?  There would be two nodes in the AlwaysOn Failover Cluster Instances setup and two Domain Controllers.  We are not using AlwaysOn Availability Groups.  Will CDC work? and will it failover? Marketing Cloud custom url expiration Is there a tool to update my PPA sources.list entries after upgrading? Rings and some of their properties So I am studying for an exam and was wondering if anyone could explain some of the reasoning being the proofs of the following properties:   Let R be a ring with $a,b\in R$. Then    $a0=0a=0$  $a(-b)=(-a)b=-ab$ $(-a)(-b)=ab$   Proof 1:   $a0=a(0+0)=a0+a0$ hence $a0=0$   I don't really understand why $a0+a0$ proves that $a0=0$ I have a WordPress website that I recently discovered had this error on the login page:     ERROR: Cookies are blocked due to unexpected output. For help, please   see this documentation or try the support forums.   I can only access the login page from wp-login.php, since /wp-admin/ displays a blank white page.  I've searched the web and tried many things with no success:   Removing ?&gt; and space at end of the functions.php Ensuring both functions.php and wp-config.php had no spaces at beginning or end of file Opening wp-config.php and functions.php in Notepad++ and converting to UTF-8 (people recommend 'without BOM' but that is only an option in the newest version of Notepad++ - I'm guessing UTF-8 does that now) I've set WP_DEBUG to true and have received no errors in debug.log,  except for 2 that relate to when I hadn't fully uploaded some files. That particular error mentioned nav-menu.php; this confirmed that it is reporting errors, just not related to my login issues I renamed each plugin folder with _tmp at the end to try and rule out any plugins causing the problem I also renamed the plugins folder to rule out all plugins at the same time   Given these things I've tried, and that I'm not receiving any PHP errors, what else could I try? Why do some Debian packages have a "+deb7u2" suffix? I figured the "7u2" part stood for "Debian 7.2" (aka "wheezy"). But I'm wondering if anybody knows the official answer as to why some packages have it and others do not.  Example:   The only time "+deb7u2" is appended to the version is when the package gets put in the "stable" release. Does this mean that's a "tag" to indicate a checkin to stable from another repo? Storing output of command in shell variable What is the difference between encrypting something and hashing something?  in what situations would I want one or the other? Want to cancel a 'Pending Erase' on iphone... Any suggestions? I lost my phone on vacation and activated 'Lost Mode' for a couple of days. The night before heading home I decided to do the Remote Erase ´cause I thought there's no way I'd get it back, I also called my carrier and canceled the data service on my number. The phone has been offline ever since but the hotel just called to say they found my phone at the spa and they are mailing it back to me. So I want to cancel the 'Pending Erase', all I care about is recovering all the pictures from that trip that I hadn't backed up on iCloud yet... Will removing the device from my iCloud account work?  And if I don't have service on the phone, will the 'Erase iPhone' command still go through when I turn it on?  Please help! I have two days to figure this out Sometimes I need to look up certain words through all the manual pages. I am aware of apropos, but if I understand its manual right, it restricts search to the descriptions only.     Each manual page has a short description available within it. apropos searches the descriptions for instances of keyword.   For example, if I look up a word like 'viminfo', I get no results at all...  $ apropos viminfo viminfo: nothing appropriate.   ... although this word exists in a later section of the manual of Vim (which is installed on my system).      -i {viminfo}                When  using  the  viminfo file is enabled, this option sets the filename to use, instead of the default "~/.vim‐                info".  This can also be used to skip the use of the .viminfo file, by giving the name "NONE".    So how can I look up a word through every section of every manual? I am carrying out research to look at differences in fish density and fish species richness when using two different underwater visual census methods. My data was originally count data but then typically this is changed to fish density but I have still decided to use a Poisson GLM, which I hope is right.   model1 &lt;- glm(g_den ~ method + site + depth, poisson)   My 3 predictor variables are method, site and depth which I ordered as factors when I input them.   My response variables are grouper species richness, grouper density and the same for other fish groups. I am aware that density is not an integer and it is numerical data e.g 1.34849. I am now however getting this error:      In dpois(y, mu, log = TRUE) : non-integer x = 0.037500   I've been reading up and many people suggest using an offset, is this the most advisable thing to do? I made a simple FM transmitter following  and it worked! Now I need some help to understand how.  My coil is made of 1 mm copper wire has 6 turns and 8 mm wire diameter. According to this online calculator:  this means that: L = 3.9e-7 H  I did not have any 5 pF trim capacitor so I used a 3 pF capacitor instead.  Am I correct in assuming that the frequency this will transmit on can be found by looking at the L1 C2 as a LC oscillator and using the frequency formulae:  fR = 1/(2*pi*sqrt(LC))  ?  If so I should get fR = 147 MHz. Which is strange since I received the signal on 91.5 MHz on my radio.  In a LC circuit I understand that the signal decays exponentially over time. That is hopefully not happening here. Why? Because of C4 maybe?  Also what is the purpose of C1?  If I want to increase the range of this FM transmitter somewhat can I do this by simply replacing R2 with a 470 Ohm resistor?  Are there free simulator programs that let me see the resulting spectrum at the antenna? Sum over multiple indices How can I "group by" and sum a column in excel? I'm trying to figure out how to "group by" values in an Excel spreadsheet.  Given the following example (this is an inventory sheet I use at my restaurant:)    At the far right of the spreadsheet there is a column named Cost of Goods Sold.  I would like to be able to come up with a total COGS figure for each Category.  Is this possible in excel? Moreover, I'd like to do it in a separate worksheet so that the first worksheet (what is pictured) isn't affected.  Any ideas?  Thanks! On iOS, while watching a video in YouTube app, when I go to the Home Screen, the video stops playing. I found no setting to enable it.  I know it is available for Android, but is there a way to do so in iOS? Is there any setting, or a 3rd party app that I can use? Mouse acceleration seems to be on by default, and I can't find anywhere in the launcher settings or the in game settings to turn it off.  It's very annoying as it makes it feel as if the mouse is lagging. Is there any way to turn it off? How to cite own unpublished work in text and reference? I would like to cite one of my own unpublished work (under review). Is it okay to cite as following?  In text According to author et al. (year of submission)................. In reference authors list, year of submission, title, name of the Journal (status)   How about the results?   How will the reviewer access those results cited here?   Is it okay to provide them as supplements?   If I provide couple of figures as supplements, whether it will violate the copyright of the under reviewed paper? Check for missing fonts/characters in XeLaTeX? Because I began to use many Unicode characters (Japanese, some unusual diacritics, etc.) I switched from LaTeX to XeLaTeX to render my documents. Unfortunately, if a font is missing, the letters are simply left out (for example, when I had forgotten to specify the font for Japanese) without any error (and I can't seem to spot a warning either). I will read the result, but I prefer to get some early warning if some character isn't available. Is there any way to get a warning about characters that have not been rendered? An error would be even better. Let $(\mathcal{H}, (\cdot, \cdot))$ be a complex Hilbert space, and $A :  \mathcal{H} \to \mathcal{H}$ a positive, bounded operator ($A$ being positive means $(Ax,x) \ge 0$ for all $x \in \mathcal{H}$). Prove that $A$ is self-adjoint. That is, prove that $(Ax,y) = (x, Ay)$ for all $x,y \in \mathcal{H}$. Here's what I have so far. Because $A$ is positive we have $\mathbb{R} \ni (Ax,x) = \overline{(x,Ax)} = (x,Ax)$, all $x \in \mathcal{H}$. Next, I have seen some hints that tell me to apply the polarization identity: $$(x,y) = \frac{1}{4}((\lVert x+y \rVert^2 + \lVert x-y \rVert^2) - i(\lVert x + iy \rVert^2 - \lVert x - iy \rVert^2)),$$ where of course the norm is defined by $\lVert \cdot \rVert^2 = (\cdot, \cdot)$. So my guess is that I need to start with the expressions: $$(Ax,y) = \frac{1}{4}((\lVert Ax+y \rVert^2 + \lVert Ax-y \rVert^2) - i(\lVert Ax + iy \rVert^2 - \lVert Ax - iy \rVert^2)),$$ $$(x,Ay) = \frac{1}{4}((\lVert x+Ay \rVert^2 + \lVert x-Ay \rVert^2) - i(\lVert x + iAy \rVert^2 - \lVert x - iAy \rVert^2)),$$ and somehow show they are equal. But here is where I have gotten stuck. Hints or solutions are greatly appreciated.