I'm excited by the sound of Blender 2.80, but I'm reluctant to abandon 2.79 as I've spent so long learning it very slowly, (I'm 63). Can I load 2.80 without destroying 2.79? Will the blend files I made in 2.79 work in 2.80? PS: I don't expect to be able to run both at the same time.
I have Blender 2.79 on my Windows 7 system.    I want to install 2.8, but I'm completing some courses which use 2.79.  If I install 2.8, will it automatically replace 2.79?  Will they interfere with one another?  Thanks.
How to salt PBKDF2, when generating both an AES key and a HMAC key for Encrypt then MAC? When using Encrypt-then-MAC with AES and HMAC by password, and given 128 bits of payload with the ciphertext to store a random salt, which would be more secure:   Using PBKDF2 with then entire 128 bit random salt and generating 512 bits of derived data to split into a 256 bit AES Key and a 256 bit HMAC key.   or   Using PBKDF2 separately for each key using two 64 bits salts to generate a 256 bit AES Key and a 256 bit HMAC key.    or    Better option? "A mice problem" vs. "a mouse problem" Last Logon Time of All Users - RDP server not on a domain How to wait in bash for several subprocesses to finish and return exit code !=0 when any subprocess ends with code !=0? How to pass javascript value to controller..? I want to pass the java-script value to controller.I am using repeat on VF page.  VF page      &lt;apex:repeat value="{!listAdj}" var="Adj" id="hrs"&gt;       &lt;td&gt;&lt;div class="requiredInput"&gt;&lt;div class="requiredBlock"&gt;&lt;/div&gt;     &lt;apex:inputField id="decimal" value="{!Adj.Hours_Decimal__c}" onchange="setHidden5(this);" &gt;       &lt;/apex:inputField&gt;     &lt;/div&gt;&lt;/td&gt;             &lt;apex:inputField id="hours" value="{!Adj.Hours__c}" /&gt; &lt;apex:inputField id="decimal" value="{!Adj.Hours_Decimal__c}" onchange="setHidden5(this);"/&gt;              &lt;/apex:repeat&gt;   Javascript code  function setHidden5(element){     //split the id of the inputField by ':' and then use the 5th index in the array to exact position of the inputField in the apex:repeat.   var idArray = element.id.split(':');     var hiddenRep1 =document.getElementById("thePage:form:hrs:hrs:"+idArray[4]+":decimal");          var hiddenRep2 = document.getElementById("thePage:form:hrs:hrs:"+idArray[4]+":hours");       if(element.value.length &gt;=1){        document.getElementById("thePage:form:hrs:hrs:"+idArray[4]+":hours").disabled = true; **hiddenRep2.value=hidden1.value;**                }                             }     }   I want to pass the hiddenRep2.value to controller.How to pass that. Hidden2.value is same as hidden1.value + some addition subtraction.i dont know how to pass that value. Can someone me sort out this.  Thanks customize of autoref How to convert standard IP address format string to hex and long? “have found” vs. “found” In  is a proof of Stirling's formula.  I really like most of it, but at a crucial step he uses the integral identity  $$n! = \int_{0}^{\infty} t^n e^{-t}  dt$$  , coming from the Gamma function.  I have a mathematical confession to make: I have never "grokked" this identity.  Why should I expect the integral on the right to give me the number of elements in the symmetric group on $n$ letters?    (It's not that I don't know how to prove it.  It's quite fun to prove; my favorite proof observes that it is equivalent to the integral identity $\int_{0}^{\infty} e^{(x-1)t}  dt = \frac{1}{1 - x}$.  But if someone were to ask me, "Yes, but why, really?" I would have no idea what to say.)  So what are more intuitive ways of thinking about this identity?  Is there a probabilistic interpretation?  What kind of random variable has probability density function $\frac{t^n}{n!} e^{-t}$?  (What does this all have to do with Tate's thesis?)  As a rough measure of what I'm looking for, your answer should make it obvious that $t^n e^{-t}$ attains its maximum at $t = n$.  Edit:  The kind of explanation I'm looking for, as I described in the comments, is similar to  of the beta integral. pc ram memory 2x1GB or 1x2GB I don't know if it's the right place to ask but can somebody advise me for buying a ram memory for my computer.  I have a Dell Vostro 200 with 1GB of RAM and 667MHz. (2 x 512MB)  I want to buy raise the amount of RAM but I'm confused whether to buy 1 x 2GB or 2 x 1GB  I know it's the same for the available amount of memory but is ther a difference maybe in the clock speed so that 2 x 667MHz will be better than 1 x 667MHz. or maybe accessing one single memory slot will be faster and better than accessing two slots.  Please anyone helps. Show that $x_{n+1}-\dfrac{x_n}{2}$ converges to zero implies that $(x_n)_n$ also converges to zero. Let $(x_n)_n$ be a sequence of real numbers such that $$\lim\limits_{n\rightarrow \infty}\left( x_{n+1} - \dfrac{x_n}{2}\right)=0.$$ Show that $(x_n)_n$ must also converge to zero.     $\textbf{My Attempt:}$   My original idea was to use the triangle inequality and the fact that $$\lim\limits_{n\rightarrow \infty}\left( x_{n+1} - \dfrac{x_n}{2}\right)=0$$   to show that the sequence $(x_n)_n$ is Cauchy and hence converges to some real number $a$, which would give me $$\lim\limits_{n\rightarrow \infty}x_n=a=\lim\limits_{n\rightarrow \infty}x_{n+1}\implies a-\dfrac a 2= \lim\limits_{n\rightarrow \infty}\left( x_{n+1} - \dfrac{x_n}{2}\right)=0\implies a=0.$$ However, I'm having trouble showing that $(x_n)_n$ is Cauchy.   Any suggestions/hints would be greatly appreciated. Thanks! Dynamically fill an Enum with a list I'm writting an addon with an UI. In my draw function in my UI class I've this   layout.prop(bpy.context.scene, 'activebone', text='active bone')   Wich create an enum in the UI.    And in my register class I've this:  bpy.types.Scene.activebone = bpy.props.EnumProperty(items=active_bone)   In my draw fonction I fill the active_bone list with the some data and but the enum don't refresh himself. I know that i can retype  bpy.types.Scene.activebone = bpy.props.EnumProperty(items=active_bone)   But the draw function is Read only so I can't. Is it possible to refresh my Enum item in the draw function or am I obliged to do it in an other class like a button? Password protected Visualforce Page rendered as PDF Is it possible that a Visualforce page rendered as pdf can be password protected?  I am using Messaging.SingleEmailMessage to send mail with attachment, but I need the attachment password protected. I have four numeric variables. All of them are measures of soil quality. Higher the variable, higher the quality. The range for all of them is different:  Var1 from 1 to 10  Var2 from 1000 to 2000  Var3 from 150 to 300  Var4 from 0 to 5  I need to combine four variables into single soil quality score which will successfully rank order.  My idea is very simple. Standardize all four variables, sum them up and whatever you get is the score which should rank-order. Do you see any problem with applying this approach. Is there any other (better) approach that you would recommend?  Thanks  Edit:  Thanks guys. A lot of discussion went into "domain expertise"... Agriculture stuff... Whereas I expected more stats-talk. In terms of technique that I will be using... It will probably be simple z-score summation + logistic regression as an experiment. Because vast majority of samples has poor quality 90% I'm going to combine 3 quality categories into one and basically have binary problem (somequality vs no-quality). I kill two birds with one stone. I increase my sample in terms of event rate and I make a use of experts by getting them to clasify my samples. Expert classified samples will then be used to fit log-reg model to maximize level of concordance / discordance with the experts.... How does that sound to you? Chrome unity shortcut acting up Whenever I click on my chrome shortcut I get a new window (as expected) but I also get a new Unity entry with a different icon (one from an iconset I had been using before upgrading to 14.04 - don't really remember the name). The new unity entry does not seem to originate from a correct .desktop entry because all the submenus are missing from it (New incognito window, New Window etc.) and it has a permanent tag '(1) Facebook' no matter the window title (see attached picture).  I have uninstalled and reinstalled chrome in hope that it would help which it did until restart but now I get the same behaviour.  Note that I haven't altered any .desktop files regarding chrome and I can only find one file:  /usr/share/applications/google-chrome.desktop which seems to be correct (with submenus etc.) Cannot install vim I am running Ubuntu 11.10, as Xubuntu, in an AMD 64 pc, configured as dual boot with Windows 7.  I tried installing vim with this:  sudo apt-get install vim   I got this error message:  The following packages have unmet dependencies:  vim : Depends: vim-common (= 2:7.3.154+hg~74503f6ee649-2ubuntu2) but 2:7.3.154+hg~74503f6ee649-2ubuntu3 is to be installed E: Unable to correct problems, you have held broken packages.   I only have a very faint idea of what the problem is, and none whatsoever on how to correct this. Hope you guys can help. Creating or referencing variables dynamically in Sass How to create my own list of things I have some section where user can upload CV and profile images,  I'm using the native attachment functions,  $attachment_cv_id = media_handle_upload( 'candidate_cv', 0 ); if ( ! is_wp_error( $attachment_cv_id ) ) {     // We link this file to the post      // add_post_meta( $result , 'wpcf-cv-file', wp_get_attachment_url($attachment_cv_id)); } else {     $submit_candidate_errors[] = lang("Hubo error subiendo la CV"); }   Is there any way I can hide this files from the media section in the wp-admin? ( perhaps changing its folder )  Thanks  -EDIT-  i'm trying like Dave suggested, adding a meta: 'rrhh-file'  $attachment_id = media_handle_upload( 'apply_file', 0 );  if ( ! is_wp_error( $attachment_id ) ) {     // The image was uploaded successfully!     add_post_meta($attachment_id, 'rrhh-file', true); }   And even that it has the attribute:  var_dump(get_post_meta(1200)); // last id I uploaded die();   Prints out:  array(4) {   ["_wp_attached_file"]=&gt;   array(1) {     [0]=&gt;     string(20) "2017/06/image001.jpg"   }   ["_wp_attachment_metadata"]=&gt;   array(1) {     [0]=&gt;     string(666) "a:5:{s:5:"width";i:523;s:6:"height";i:122;s:4:"file";s:20:"2017/06/image001.jpg";s:5:"sizes";a:2:{s:9:"thumbnail";a:4:{s:4:"file";s:20:"image001-150x122.jpg";s:5:"width";i:150;s:6:"height";i:122;s:9:"mime-type";s:10:"image/jpeg";}s:6:"medium";a:4:{s:4:"file";s:19:"image001-300x70.jpg";s:5:"width";i:300;s:6:"height";i:70;s:9:"mime-type";s:10:"image/jpeg";}}s:10:"image_meta";a:12:{s:8:"aperture";s:1:"0";s:6:"credit";s:0:"";s:6:"camera";s:0:"";s:7:"caption";s:0:"";s:17:"created_timestamp";s:1:"0";s:9:"copyright";s:0:"";s:12:"focal_length";s:1:"0";s:3:"iso";s:1:"0";s:13:"shutter_speed";s:1:"0";s:5:"title";s:0:"";s:11:"orientation";s:1:"1";s:8:"keywords";a:0:{}}}"   }   ["rrhh-file"]=&gt; // &lt;-- here   array(1) {     [0]=&gt;     string(1) "1"   }   ["_edit_lock"]=&gt;   array(1) {     [0]=&gt;     string(12) "1498731595:1"   } }   With this action this attachment still shows up in the media library  add_action( 'pre_get_posts', 'wpse_hide_cv_media_list_view' ); function wpse_hide_cv_media_list_view( $query ) {     // Bail if this is not the admin area.     if ( ! is_admin() ) {         return;     }      // Bail if this is not the main query.     if ( ! $query-&gt;is_main_query() ) {         return;     }      // Only proceed if this the attachment upload screen.     $screen = get_current_screen();     if ( ! $screen || 'upload' !== $screen-&gt;id || 'attachment' !== $screen-&gt;post_type ) {         return;     }      // Modify the query.     $query-&gt;set( 'meta_query', [         [             'key'     =&gt; 'rrhh-file',             'compare' =&gt; 'NOT EXISTS',         ]     ]);      return; }   Any idea what i'm missing? Where does the energy for osmosis come from? A thought experiment:     A U-shaped tube with semi-permeable membrane at the base. The tube is completely thermally isolated from its surroundings. The liquid (solvent) is at some temperature $T$. When solute is added to one side of the tube the fluid level on that side rises until the increased pressure due to gravity ($\rho gh$) equals the osmotic pressure.   If I understand correctly, osmotic pressure could be used to do work (i.e. lift a weight as the solvent level in one side of U-shaped tube increases). Where does this energy come from? I guess it must be from the internal energy of the fluid.  At this point has the temperature of the fluid decreased?? If so, has it decreased by exactly the work done against gravity divided by the specific heat of the fluid? What does the quantitative treatment of this problem look like?