W: Failed to fetch http://ppa.launchpad.net/ferramroberto/java/ubuntu/dists/raring/main/binary-amd64/Packages  404  Not Found W: Failed to fetch http://ppa.launchpad.net/ferramroberto/java/ubuntu/dists/raring/main/binary-i386/Packages  404  Not Found E: Some index files failed to download. They have been ignored, or old ones used instead.   I keep getting this when I download anything from the terminal.  How do I get around this?
PPA seems to be constantly offline. Whenever I use sudo apt-get update, this error is shown:  W: Failed to fetch http://ppa.launchpad.net/ 404  Not Found   How do I fix these errors?
What do I set the 'Opens with...' property to in order to get the system to run .bat files again (when they are double-clicked)?  Somehow my boss convinced his workstation that the handler for .bat files was supposed to be Word. Now, when double-clicking .bat files, they're opened up in Word. Trigger to use HTTP callout and update record with the results I have been trying to integrate Google Shortener API into my salesforce org. I wrote a class to make the call out, but am having difficulty bringing the value back into the record. I have a custom object called "referral_advocate__c" with a field called "Short_URL__c". Anytime the field "unique_ID__c" has a value, I am wanting to send this value with a static URL to google shortener and then save the response value to "referral_advocate__c.short_URL__c" on the record. This is the class to make the call out:  public class URLshort {  final string urls = 'https://www.myurl.com'; referral_advocate__c adv = new referral_advocate__c();  @future(callout = true) public static void URLshortner() {      HttpRequest req = new HttpRequest();     HttpResponse res = new HttpResponse();     Http http = new Http();      req.setEndpoint('https://www.googleapis.com/urlshortener/v1/url?key=myapikey');     req.setMethod('POST');     req.setHeader('Content-Type','application/json');            req.setBody('{"longUrl":+urls + adv.unique_reference_number_c}');       try {         res = http.send(req);         System.debug(res.getBody());     } catch(System.CalloutException e) {         System.debug('Callout error: '+ e);         System.debug(res.toString());     }   }  }   The after insert trigger on "referral_advocate__c" I wrote is not firing correctly. How do I return the results from this class and update the field "short_URL__C" with the returned value from a trigger? $\sum a_{n}$ is convergent, $\sum a_{n}^2$ is divergent. Prove $\sum a_{n}$ is conditionally convergent. Suppose that the series $\sum_{n=1}^{\infty}a_{n}$ converges while $\sum_{n=1}^{\infty}a_{n}^2$ diverges. Prove that $\sum_{n=1}^{\infty}a_{n}$ converges conditionally. A couple years ago I ran upon a  video demonstrating how researchers used x-rays given off by tearing tape off its spindle in hopes to miniaturized and cheapen future x-ray devices. As of late I have been wondering what interactions are causing this. I understood from the video that the electrons are being ejected due to the added energy to the system (peeling). This instinctively pointed me towards QED where interactions between electrons produce a photon for short periods. 1)Are those same photons from electron interaction the resulting x-rays? 2)Are the frequencies of the photons being limited by the $\Delta$energy$\Delta$time uncertainty, and/or $\Delta$position$\Delta$momentum uncertainty (at the vertex of the ripping tape, where high densities of electrons may accumulate) ? Note: I've also considered that the van der Waals force may come into consideration, not certain though. Looking for a QED based descriptions/answers. Any elementary references to this work is appreciated. Have red shifted photons lost energy and where did it go? I think the title says it. Did expansion of the universe steal the energy somehow? If $(a_n)\subset[0,\infty)$ is non-increasing and $\sum a_n<\infty$, then $\lim{n a_n} = 0$ I'm studying for qualifying exams and ran into this problem.  Show that if $\{a_n\}$ is a nonincreasing sequence of positive real numbers such that $\sum_n a_n$ converges, then $\lim_{n \rightarrow \infty} n a_n = 0$.  Using the definition of the limit, this is equivalent to showing \begin{equation} \forall \varepsilon &gt; 0 \; \exists n_0 \text{ such that } |n a_n| &lt; \varepsilon \; \forall n &gt; n_0 \end{equation} or \begin{equation} \forall \varepsilon &gt; 0 \; \exists n_0 \text{ such that } a_n &lt; \frac{\varepsilon}{n} \; \forall n &gt; n_0 \end{equation} Basically, the terms must be bounded by the harmonic series. Thanks, I'm really stuck on this seemingly simple problem! Example of mailmerge package with an Excel spreadsheet I am looking for an example for using the  package to write a cover letter, with names and addresses on a spreadsheet. The package comes with an example, but you have to manually enter all the data. Passing list to viewparams variables in GeoServer SQL views? Is there a program equivalent to lint for LaTeX? Is there a program equivalent to lint for LaTeX? (lint checks C code for syntax errors and possible mistakes.) What is the meaning of the term "thread-safe"? Does it mean that two threads can't change the underlying data simultaneously? Or does it mean that the given code segment will run with predictable results when multiple threads are executing that code segment? I hear a lot of people saying that neutrino is the lightest subatomic particle but according to me a photon must be the lightest as nothing can travel faster than light because it gets heavier and heavier and bends time. How to set vertex weights using Blender's Python API? Looking at the API docs I found , but It cannot be called in Edit Mode. When I try to call it, I always get:     RuntimeError: VertexGroup.add(): cannot be called while object is in edit mode.   The buttons in the vertex group list use bpy.ops.objects.vertex_group_assign(), but to work with it you have to manipulate selections, this is not nice to do from a script.    Why I try to use VertexGroup.add() in Edit Mode? My script works this way:  Human weight paint a bone, "Arm_1.L", "Arm_1.L" shares vertices with "Arm_2.L" in this case they share half the vertices (4 bone arm rig, trick to have nice deform in certain movements). When script run, all selected vertices that exist in both groups (Arm_1.L and Arm_2.L) will copy the weights of Arm_1.L into Arm_2.L but inverted. This way, I only need to weight paint "Arm_1.L" and "Arm_3.L", the script will fill the weights for "Arm_2.L".  import bpy  # ensure we are in edit mode bpy.ops.object.mode_set(mode="EDIT")  # configurable parameters src_group = "Arm_03.L" dst_group = "Arm_02.L"  obj = bpy.context.edit_object src_group_index = obj.vertex_groups[src_group].index dst_group_index = obj.vertex_groups[dst_group].index  mesh = obj.data sel_verts = [v for v in mesh.vertices if v.select] #sel_verts = mesh.vertices  # SEGFAULT in this line bpy.ops.object.mode_set(mode="OBJECT")  print("Working")  for v in sel_verts:     v1in = False     v2in = False     for g in v.groups:         if g.group == src_group_index:             v1in = True         if g.group == dst_group_index:             v2in = True     if v1in and v2in:         print("True")         obj.vertex_groups[dst_group].add([v.index], 1.0 - obj.vertex_groups[src_group].weight(v.index), 'REPLACE')  print("Finished") An improved \rowstyle that takes the cell contents as an argument It is possible to format the column entries of a tabular in an argument-style fashion using the lrbox environment to   store the column cell in a box (say) \mybox; and supply \mybox as an argument to some other macro.   Here is a short example illustrating this fact*:  \documentclass{article} \usepackage{array}% http://ctan.org/pkg/array \begin{document} \newsavebox{\mybox} \begin{tabular}{c&gt;{\begin{lrbox}{\mybox}}c&lt;{\end{lrbox}\fbox{\usebox{\mybox}}}c}   One &amp; Two &amp; Three \\ \hline   1 &amp; 2 &amp; 3 \\   4 &amp; 5 &amp; 6 \\   7 &amp; 8 &amp; 9 \\ \hline \end{tabular} \end{document}     The above example uses the  to achieve this column-specific formatting. More specifically, each cell in the column is supplied as an argument to \fbox. Does there exist an equivalent automation that would yield    \documentclass{article} \begin{document} \begin{tabular}{ccc}   One &amp; Two &amp; Three \\ \hline   1 &amp; 2 &amp; 3 \\   \fbox{4} &amp; \fbox{5} &amp; \fbox{6} \\   7 &amp; 8 &amp; 9 \\ \hline \end{tabular} \end{document}   without having to specify \fbox for each entry in the row?  As a start, I know that the  provides \rowfont[&lt;alignment&gt;]{&lt;font specification&gt;}. However, this only applies macros &lt;font specification&gt; to each cell in a row and these macros can't take the cell contents as an argument. Moreover, you need to use the tabu environment in order to use this. So that's a little restricting. Also, trying to decipher the  macros for colouring a tabular or array row is just confusing.  The UK TeX FAQ entry on  modifies the row entries via column specifications and therefore requires the addition of "subtle" identifiers like  \begin{tabular}{|$l|^l|^l|}   to initiate $ and propagate ^ whatever row style is defined. Is there a way around this or at least a cleaner alternative that doesn't use columns to format entries in a row? In particular, a solution should provide an lrbox-style flexibility, since the contents of the cell in the to-be-styled row could be anything, even a paragraph (say).  * There are other alternatives, as indicated by the post . How to compute $\int_0^{\pi/2}\frac{\sin^3 t}{\sin^3 t+\cos^3 t}dt$? Calculating with Mathematica, one can have $$\int_0^{\pi/2}\frac{\sin^3 t}{\sin^3 t+\cos^3 t}\,\mathrm dt=\frac{\pi}{4}.$$   How can I get this formula by hand? Is there any simpler idea than using $u = \sin t$?     Is there a simple way to calculate $$ \int_0^{\pi/2}\frac{\sin^n t}{\sin^n t+\cos^n t}\,\mathrm dt $$ for $n&gt;3$? Could anyone come up with a reference for this exercise? Transitive subgroup of symmetric group $S_n$ containing an $(n-1)$-cycle and a transposition Number of non decreasing sequences of length $M$ How many non decreasing sequences are there of length $M$, provided the number in the sequences are allowed from $1,2,3,...,N$? Given a Lie group, how are you meant to find its Lie algebra?  The Lie algebra of a Lie group is the set of all the left invariant vector fields, but how would you determine them?  My group is the set of all affine maps $x \rightarrow A.x+v$ from $R^n$ to $R^n$ under function composition. Bash: Syntax Error on @() If two limits don't exist, are we sure the limit of sum doesn't exist? This is a true/false question.     If the limits $$\lim_ {x\to a}\ f(x)\quad \text{ and }\quad  \lim_ {x\to a}\ g(x)$$ don't exist, limits $$\lim_ {x\to a}\ (f(x)+g(x))\quad \text{ and }\quad \lim_ {x\to a}\ (f(x)g(x))$$ don't exist also.   My idea is, that, because $$\lim_ {x\to a}\ (f(x)+g(x))=\lim_ {x\to a}\ f(x)+\lim_ {x\to a} g(x)$$ then the limits doesn't exist, correct? This question arises when I try to describe my itinerary to ticket service in the UK. Take for example, I plan to buy a ticket from A to B. B is the terminal. How to say its counter part A? I cannot find a proper term. I have to say "I will depart from A" or "I plan to go to B from A". Or I even use "departure place" to refer to B.