Difference between forms of Internal energy equation
What is the difference between $Q=\Delta U+W$ and $\Delta U=Q+W$?
If $X$ takes on a Gamma Distribution, how can I find $X^2$, $X^3$, etc? Create model from XYZ data points I'm trying to create a 3D heat map model out of data that I have from a csv file. I have a few thousand data points with XYZ coordinates.  I'm able to import the data into blender as a point cloud with , however I would like to create a model with solid faces. Is there a way when importing the data to somehow join the points to create faces instead of generating thousands of separate points?  Currently, this what I have in terms of point cloud  The end product would look something like this (minus the texture) and obviously the model wouldn't be as regular as this one  Any help is greatly appreciated! How to get RGB values from UIColor? NOTE: I am not interested in calling /secur/logout.jsp since it ends all the active salesforce sessions.  I am developing a web application that is registered on salesforce as a connected app, so I am using salesforce credentials to authorize the user.  Application is developed in REST API and the communication with salesforce is happening in restful manner.   Auth url:   Authorization:  Method 1: If there is no salesforce session active, The user is taken to salesforce login page, where he enters his salesforce details to be authorized and after which he is taken to home page of my web application.  Method 2: If there is already a salesforce session active in another tab, the user is directly authorized and is taken to home page of my web application.  Now I am trying to implement logout button for my application, such that the following scenarios are covered,  Scene 1: The user is authorized using method1, and the user press the logout. Upon trying to logback the user is prompted for credentials.  Scene 2:  The user is authorized using method2, and the user should use logout to logout of the web application (not from active sessions). Upon login, the user should be again able to login using method2.  Can someone help me on how to implement the logout button such that it covers scenario 1 &amp; 2.  Thanks in advance. Is 20 watts of electricity dangerous? I have a few circumstances which invlove someone being shocked with 20 watts of electricity and whether it would be deadly. So here they are:   Would 1000 volts at 20 miliamperes of AC (2MHz frequency) be dangerous or deadly? Would 1000 volts at 20 miliamperes of DC be dangerous or deadly? Would 10 Kilo volts at 2 miliamperes of AC (2MHz frequency) be dangerous or deadly? and Would 10 Kilo volts at 2 miliamperes of DC be dangerous or deadly?   Thanks for everyones help. Say a creature owns multiple items with wording similar to this:  As an Action, you may speak the command word to [...]  Say the creature has deliberately obtained such items, perhaps by creating them itself, to have the same command word. Can this creature use one action to speak the shared command word and activate multiple items at once? The purpose of this question is not to cheese my DM. I am writing a short story and like to keep my D&amp;D fiction as close to rules-accurate as possible. Display sheet name in Google Spreadsheets Is there any way to display a sheet name as the result of a function in a Google Spreadsheets (exactly like , except in Google Sheets)? Can you be refused a visitor visa to US if you have bad Credit there? How do I read image files directly from a zip without extracting to disk? Is it possible to reset all folder permissions? I was wondering if it was possible to reset all the folders' rights. I was having trouble when trying to install LAMP on my Ubuntu 11.04 installation, and I modified many permissions like /var /etc and I want to cancel everything I did and have permissions set to how they would be after a new install. Massless charged particles When I add a mirror modifier it sometimes doesn't mirror correctly, giving me an overlapping mesh. How can I fix this? Is there any way to favorite/bookmark an answer? Lots of questions are very generic, &quot;share an experience&quot; kinds of questions. In these cases, I am quite often interested in specific answers that may not have gotten that many upvotes. These questions also tend to elicit lots of responses, so going back to find the answers I'm interested in somewhere in the middle of a sea of responses is a pain. Is there a way to favorite or bookmark these answers? Pokemon GO isn't working at all for me right now. I'm in one of the following circumstances and can't do anything:   My game is displaying a "Try Again" message I'm stuck on the Loading Screen When I sign in I get a message that the servers are experiencing problems. I see the map but nothing is loaded, and my team color is wrong The "loading" Pokeball just ends up spinning and I can't catch or interact with things When I try to catch a Pokemon, the Pokeball just sits on my screen doing nothing Gym opponents will drop to 1 HP and won't take any more damage or attack When I open a pokestop, the pokestop image and the name of the pokestop does not load.   What's causing this? Is there a way to fix it? When I try to remove Java with sudo apt-get remove jdk1.8.0-40 I get this:    Reading package lists... Done Building dependency tree        Reading state information... Done The following packages will be REMOVED:   jdk1.8.0-40 0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 245 MB disk space will be freed. Do you want to continue? [Y/n] y (Reading database ... 231488 files and directories currently installed.) Removing jdk1.8.0-40 (1.8.040-1) ... find: `/usr/java/*': No such file or directory /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 586: /usr/sbin/alternatives: No such file or directory /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 598: /usr/sbin/alternatives: No such file or directory dpkg: error processing package jdk1.8.0-40 (--remove):  subprocess installed post-removal script returned error exit status 127 Errors were encountered while processing:  jdk1.8.0-40 E: Sub-process /usr/bin/dpkg returned an error code (1)   Output of  ls -1 /var/cache/apt/archives/*jdk*:  openjdk-7-jre_7u75-2.5.4-1~trusty1_amd64.deb openjdk-7-jre-headless_7u75-2.5.4-1~trusty1_amd64.deb   Output of sudo dpkg --purge --force-all jdk1.8.0-40:  (Reading database ... 231488 files and directories currently installed.) removing jdk1.8.0-40 (1.8.040-1) ... /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 586: /usr/sbin/alternatives: No such file or directory /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 598: /usr/sbin/alternatives: No such file or directory dpkg: error processing package jdk1.8.0-40 (--purge): subprocess installed post-removal script returned error exit status 127 Errors were encountered while processing:  jdk1.8.0-40   When trying the edit I get this:  (Reading database ... 231488 files and directories currently installed.) Removing jdk1.8.0-40 (1.8.040-1) ... /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 586: /usr/sbin/alternatives: Permission denied /var/lib/dpkg/info/jdk1.8.0-40.postrm: line 598: /usr/sbin/alternatives: Permission denied dpkg: error processing package jdk1.8.0-40 (--remove):  subprocess installed post-removal script returned error exit status 126 Errors were encountered while processing:  jdk1.8.0-40 E: Sub-process /usr/bin/dpkg returned an error code (1) How do I appropriately examine the dimensionality of binary data? I have 72 binary variables and, at a theoretical level, I am trying to identify groups of variables that seem to vary together. In practice, I am struggling with how to analyze this data properly. I am using R and the psych package. Here is what I have tried and what the outcomes were:  Estimated a tetrachoric correlation matrix (ran without problem) Estimated MSA (relatively strong values, ran without problem) Ran parallel analysis to identify how many factors to extract (ran without problem) EFA using fa() to estimate factors (non-positive definite matrix and strangely high RMSEA) Tried different factor counts, smoothing/unsmoothing, estimation methods, rotations methods, and removing variables (problems persisted) Tried to focus instead on eBIC (always returned as NULL in output) EFA using (inappropriately) Pearson correlations (RMSEA behaved)  From looking at other questions and answers on here, I am now aware that tetrachoric matrices can be problematic like this. However, I don't know what to do with that information. Accept the problems as a limitation and move forward? Conduct a different type of analysis? I considered IRT as is recommended, but am unaware of an exploratory way to conduct IRT analyses. I understand that most of my options are imperfect. My goal is to find an analysis that is at least arguably appropriate for binary variables and that will inform the ways in which I group these variables in my theorizing. Given this, my questions are:  Can I trust EFA on a tetrachoric matrix despite problematic output? Can I somehow recover the lost eBIC value and use that? Is exploratory IRT possible/desirable? Are there other analyses, in R, that can be used to examine the dimensionality of binary data?  I appreciate all feedback! I love learning about data analysis and hearing about how I can improve. I have a table tabName with the following rows:  id(PK) .. Created(datetime)     Resolved(datetime) Status(new/resolved/open) 1          2015-05-10 00:00:00   1970-01-01 ..       open 2          2015-05-10 ..         1970-01-01 ..       new 3          2015-05-10            2015-05-12          resolved 4          2015-05-11 ..         1970-01-01 ..       open 5          2015-05-11 ..         1970-01-01 ..       new 6          2015-05-11            2015-05-11          resolved 7          2015-05-12 ..         1970-01-01 ..       open 8          2015-05-12 ..         1970-01-01 ..       new 9          2015-05-12            2015-05-12          resolved   NOTE:  1970-01-01 .. is default time for all the tickets which are still open.  I have to frame a query to get the count of tickets still open, date wise. Say like on 10 May I have 3 tickets opened. Noting that for id = 3, resolved date is not 10 but it's closed on 12 May.  I framed a query like  SELECT DATE_FORMAT(Created, '%d-%m') AS createdd, COUNT(1) FROM tabName WHERE DATE_FORMAT(Resolved, '%d-%m') &gt; DATE_FORMAT(Created, '%d-%m')       AND YEAR(Created) = '2015' GROUP BY createdd;   The above query gets all the tickets whose Resolved date is greater than the date which is considered for the count. This may count newer tickets as well. And also if the older tickets which are not resolved yet is not counted.  Is there any other way to frame the required query? I have been juggling with this query from last 3 days. Not able to find out still.  Updated: As suggested by Abhik, i have tried in sqlfiddle site.  Here is what i created:  CREATE TABLE test    (idint,createddatetime,resolveddatetime, status varchar(15), PRIMARY KEY (id));    INSERT INTO test       (id,'created','resolved',status`) VALUES       (1,'2015-05-10 00:00:00','1970-01-01 00:00:00','open'),    (2,'2015-05-10 00:00:00','1970-01-01 00:00:00','new'),    (3,'2015-05-10 00:00:00','2015-05-12 00:00:00','resolved'),    (4,'2015-05-11 00:00:00','1970-01-01 00:00:00','open'),    (5,'2015-05-11 00:00:00','1970-01-01 00:00:00','new'),    (6,'2015-05-11 00:00:00','2015-05-11 00:00:00','resolved'),    (7,'2015-05-12 00:00:00','1970-01-01 00:00:00','open'),    (8,'2015-05-12 00:00:00','1970-01-01 00:00:00','new'),    (9,'2015-05-12 00:00:00','1970-01-01 00:00:00','open')    ;   `   When i run  ` select created_date, @open:= @open+open_ticket-resolved as open from(  select   date_format(created,'%d-%m') as created_date ,  sum( case when status='open' then 1 else 0 end )+  sum( case when status='new' then 1 else 0 end )+  sum( case when status='resolved' and ( date(resolved) > date(created) or  date(resolved) = date(created)) then 1 else 0 end ) as open_ticket,  sum(case when status = 'resolved' and date(resolved) = date(created) then 1   else 0 end) as resolved  from test  where  YEAR(Created) = '2015'  group by created_date )x,  (select @open:=0)r order by created_date ; `  I got following output  created_date   open 10-05   3 11-05   5 12-05   8  Here count of still open tickets for 12-05 must be 7. The above query includes ticket id "3" , which is closed on 12-05. So is there any way to exclude this? If i am able to get this right, then i will have full fledged query. A mathematically mature introduction to Turing Machines and Computability [reference-request] In the computer science course for mathematicians held at my university Turing Machines have been presented very briefly. So much so that I didn't quite get why they are relevant to mathematics. I did understand what a Turing Machine is, but I feel that the presentation given was (for schedule reasons) quite naive and simplified. So I would like to ask if you can point out a good reference for a mathematically mature introduction to turing machines and computability. Solving $x^p + y^p = p^z$ in positive integers $x,y,z$ and a prime $p$ The question is from Zeitz's ''The Art and Craft of Problem Solving:"      Find all positive integer solutions $x,y,z,p$, with $p$ a prime, of the equation $x^p + y^p = p^z$.   One thing I noticed is that   $$ \frac{x^p + y^p}{x + y} = \sum_{i=0}^{p-1}x^{(p-1)-i}(-y)^i \implies (x+y) |p^z \implies x + y = p^n, \text{ }n &lt; z   $$  It is also not hard to determine all solutions for $p =2$. After this, however, I am at a loss. I don't know what restrictions I can impose to try to narrow down the solution set; for example, the class of solutions  $$ p=3, x = 3^n, y = 2\cdot3^n, z = 2 + 3n $$  for $n \ge 0$ show that $x+y = p^n$ cannot be sharpened. (Let me note that these are the only other solutions I have found besides the ones for $p = 2$.)  Could anybody give me a push in the right direction on this problem? Does installing many programs really slow down Windows?