How to find the third latest date from a list of dates
Understanding slice notation
What are the limitations of a typical kit lens as a general purpose lens? I have a Canon EOS 550d with the 18-55mm IS kit lens. I have done  (portraits, nature, night shots etc), and find the image quality to be pretty good. In fact most of the reviews have also been positive (at least in terms of image quality):   Quote:     indeed Canon's main concern may   ultimately become whether users have   as much incentive to upgrade to more   expensive optics as they did before       So, what are the key limitations of this lens (or any other similar kit lens) that would compel one to upgrade to a more expensive general purpose zoom lens (apart from the wanting to upgrade the zoom range)? What's the difference between align and align*? After some brief searching I can't find the difference between align and align*. Google summarily ignoring the * is making it harder I think.  Can you tell me the difference between these two?  Moreover, can you tell me where you generally go for this type of information? As a relatively new user I'm still building up my resources. Service or services? I've read many articles that use the term 'emergency services ' and ' location services' .   Why not service instead? Why must it be plural? Thank you 7 month old wants to sleep on its belly -- is it safe? Java Access Denied I tried control+shift+power button as well as command+shift+power button. Neither seem to work. What is the single most influential book every designer should read? What is the single most influential book every designer should read? Coefficient changes sign when adding a variable in logistic regression In my logistic regression the sign of coefficients of a variable (location distance of an amenity) changes based on other variables (with time -ve, with travel distance +ve) in the model. When the location distance is the only variable in the model, it has +ve sign.    Should the variable need to maintain the +ve sign no matter what other variables are added in the model? Does changing sign signify a multicollinearity issue? Some IVs are gaining significance while in a bivariate model, they didn't show significance and vice versa. Is it okay to add variables that don't have much significance (ex: travel distance has a significance of 0.33 individually, but 0.05 when added with other variables) but becomes significant in the model? thanks. Decode Base64 data in Java I have an image that is Base64 encoded. What is the best way to decode that in Java? Hopefully using only the libraries included with Sun Java 6. What does !function ($) { $(function(){ }) }(window.jQuery) do? I've been playing the game a while now and have ranked up considerably. I'm wondering if there is any way to change to a different Google account and still keep all of my Pokemon/items etc, as I stupidly used my university gmail account when I first downloaded the app (which will be automatically deleted in September).   Is there any way to transfer my trainer/Pokemon/items etc to a different Google account? I see a lot of example code for C# classes that does this:  public class Point {     public int x { get; set; }     public int y { get; set; } }   Or, in older code, the same with an explicit private backing value and without the new auto-implemented properties:  public class Point {     private int _x;     private int _y;      public int x {         get { return _x; }         set { _x = value; }     }      public int y {         get { return _y; }         set { _y = value; }     } }   My question is why. Is there any functional difference between doing the above and just making these members public fields, like below?  public class Point {     public int x;     public int y; }   To be clear, I understand the value of getters and setters when you need to do some translation of the underlying data. But in cases where you're just passing the values through, it seems needlessly verbose. Creating new layers using ArcPy to define Definition Query for each field value? I am trying to set multiple definition queries for one layer based on one field using python.  ie.  I have a City layer with a field that holds the city name.  I want a copy of the layer in an MXD with the Definition query set for each value in the City field.  So essentially, I have one source layer, with a copy of the layer as many times as there are values in the City field.  The query would look like this: CITY = 'Atlanta' Question Tag problem! Question:     A man like you should not do this, _______?   Which question tag should I use in the blank space?   should he? should you?   Which would be grammatically correct? I think 1 is true. Every subspace of a compact space is compact? It seems as if every subspace of a compact topological space (equipped with its relative topology) had ought to be compact as well. Is this true in general?  And in particular, I want to use the fact that every quasi-projective variety is compact with the Zariski topology - I remember having proven it for quasi-affine varieties, but the same proof does not work for quasi-projective varieties. Is every quasi-projective variety compact? Form within a block I'm using drupal_get_form('event_signup_form') to embed my custom form inside a block. The form is being rendered as intended, but submitting the form triggers nothing.  The form function itself is called event_signup_form($form, &amp;$form_state) and the submit function is called event_signup_form_submit($form, &amp;$form_state) but it's not being called.  I am using  to show the form:  function event_block_view($delta = '') { $blocks = array(); if ($delta ...) { $blocks['content'] = drupal_render(drupal_get_form('event_signup_form')); } }   I managed to get this working - here is how (stub):  function hook_block_view($delta = '') { $blocks['content'] = drupal_render(drupal_get_form('event_signup_form')); }  function event_signup_form() { // Register form submit handler, same goes for validation handler $form['#submit'][] = 'event_signup_form_submit';  return $form; }  function event_signup_form_submit($form, &amp;$form_state) { // This is now triggered } How do I install drivers for an Intel HD Graphics? In System Info in 11.10, the graphics driver wasn't detected. I use ACER Aspire 4750 with Intel Core i3-2340M and Intel HD Graphics 3000 graphic card  How to install the driver for my Ubuntu? Why don't websites immediately display their text these days? I've noticed that recently many websites are slow to display their text. Usually, the background, images and so on are going to be loaded, but no text. After some time the text starts appearing here and there (not always all of it at the same time).  It basically works the opposite as it used to, when the text was displayed first, then the images and the rest was loading afterwards. What new technology is creating this issue? Any idea?  Note that I'm on a slow connection, which probably accentuates the problem.  See below for an example - everything's loaded but it takes a few more seconds before the text is finally displayed: How do I find values not given in (interpolate in) statistical tables? Often people use programs to obtain p-values, but sometimes - for whatever reason - it may be necessary to obtain a critical value from a set of tables.   Given a statistical table with a limited number of significance levels, and a limited number of degrees of freedom, how do I obtain approximate critical values at other significance levels or degrees of freedom (such as with $t$, chi-square, or $F$ tables)?  That is, how do I find the values "in between" the values in a table? The Higgs boson and gluons have no electric charge and photons couple to charge, so there is no tree level interaction between them and photons.  But what prevents higher order diagrams from contributing a non-zero mass term to the photon, for instance    where a photon couples to some fermion (say an electron, or a top quark) which can interact with the Higgs field.   Or consider that same diagram but with quarks and a gluon interacting between them? Or any higher diagram with even more loops?  I have heard charge conservation depends on gauge invariance, which in turn depends on photons being massless.  So it appears the photon has no mass, and these diagrams must all cancel somehow.  So I'm hoping there is a very nice symmetry explanation for why they all disappear, but if I say "because of gauge invariance" that would be circular logic, so there must be another symmetry at stake here?     What prevents photons from obtaining a mass from high-order self-energy loop diagrams?