How can I safeguard my Php Form?
How can I prevent SQL injection in PHP?
$IS \mid JS$ implies that $I\mid J$ where $I$ and $J$ are ideals of a number ring contained in another number ring $S$ What do repeating '^@' symbols in a logfile mean? A few times I have come across this in a log file:  Sep 17 09:35:57 00187d378926 ovpn-00187d378926[1701]: /sbin/ifconfig tun0 0.0.0.0 Sep 17 09:35:57 00187d378926 kernel: Kernel logging (proc) stopped. Sep 17 09:35:57 00187d378926 rsyslogd: [origin software="rsyslogd" swVersion="4.6.4" x-pid="1707" x-info="http://www.rsyslog.com"] exiting on signal 15. ^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@ ^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@ ^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@   What does it mean?  Sometimes it is a single line, other times it is lots of lines.  I usually see it happen on Debian 6 machines. How are "needs to be washed," "needs washing," and the regional variant "needs washed" to be distinguished"? I'm from Central Pennsylvania, and apparently, we have a strange language construct in this area. I was recently talking about how "my car needs washed" to a friend from NJ, and she told me that my sentence was grammatically incorrect.   I realize she's right, and I realize my options are "my car needs to be washed" or "my car needs washing". But I'm not clear on the precise rule being invoked. Series $\sum_{n=1}^\infty \frac{n^n}{(n!)^2}$ How can I output colored text to the terminal in Python? What is $\int_{c}^{\infty}\Phi(a+bx) \phi( x ) dx$ for $c\in\mathbb{R}$ It is straightforward to show $$\int_{-\infty}^{\infty}\Phi(a+bx) \phi( x ) dx = \Phi\left(\frac{a}{\sqrt{1+b^2}}\right)$$ but what value does $$\int_{c}^{\infty}\Phi(a+bx) \phi( x ) dx$$ have for $c&lt;\infty$, e.g., for $c=0$? Even a good approximation would really help me! TikZ: Bend text so that it follows a line I have two arrows going from a node on the left to a node on the right. Both arrows are slightly bent. I want to label the arrows with text that is bent just like the arrows. This is as far as I've got:  \begin{tikzpicture} \node (One) at (-3,0) [shape=circle,draw] {One};  \node (Two) at (3,0) [shape=circle,draw] {Two}; \draw [-&gt;, thick] (One) to [bend right=45]  (Two); \draw [-&gt;, thick] (One) to  [bend left=45] (Two); \node (mental) at (0,1.75) {Some bent text}; \node (non-mental) at (0,-1.75) {Some more bent text}; \end{tikzpicture} Prerequisites for classical mechanics by Susskind So I am an undergraduate in Electrical Engineering. We had a course on Physics in our freshman year which is equivalent to Classical Mechanics I as taught in MIT. I am interested in studying advanced classical mechanics (which includes Lagrangian formulation and other stuff) as equivalent to Classical Mechanics lecture by Susskind. I wanted to know are they any prerequisites which I should know about before taking this course.   In general what are the prereqs for this course? Baking IK into FCurves I have an object containing multiple models with several IK.  One model has fcurves (euler rotation only) which gives motor to linked IK models.  What I need is bake/convert all IK animations into FCurves.  Is it possible? Meridian convergence. True north, magnetic north and grid north I'm having difficulty wrapping my mind around meridian convergence, the horizontal angular distance between true north and grid north.   Say I want to determine if a feature lies to the east or west of the central meridian (CM) by using true north and grid north designations on a topo map.   I realize grid north is parallel to the CM, while true north points to the poles, and magnetic north is the direction a compass points and constantly changing.   Looking at the figure below, I see grid north points to the east of true north. So does this fact alone mean everything on the grid is to the east of the true north, and therefore the CM? Does this simple fact mean that features in this grid lie to the east of the CM, or am I missing something.   Also, I realize I can just look at the tick marks and and see that this this grid in particular covers -80°22’ to -80°15, and the CM for zone 17R lies at 81°. But had I not known that and wanted to use the north arrows. Please explain. What is the number of automorphisms (including identity) for permutation group $S_3$ on 3 letters? In the Lord of the Rings it is said     "In Eregion long ago many Elven-rings were made, magic rings as you   call them, and they were, course, of various kinds: some more potent   and some less. The lesser rings were only essays in the craft before   it was full-grown, and to the Elven-smiths they were but trifles — yet   still to my mind dangerous for mortals. But the Great Rings, the Rings   of Power, they were perilous.”   [LotR I 2 (60)]   There is a clear distinction here between the 20 Rings of Power in the Ring Rhyme (the 7,9,3,and 1) and these other rings. What happened to the "lesser rings"? How to customize the Ubuntu Live CD? I would like to customize Ubuntu live CD by installing some additional packages. I have followed   but it doesn't seems to work. Can anyone provide clear instructions?   Note: I do not prefer Remastersys, manual way will be appreciated.  Customization  Packages that I want to install:   Thunderbird    Samba    SSH       Changes that I need:   Remove Games menu from the Application menu Firefox shortcut on Desktop Radiance as the default Theme Different default Ubuntu Wallpaper   Configuration file changes   I want the panel to be placed at the bottom I want to paste my Samba configuration file instead of default Samba configuration I have few Firefox shortcuts and folders I would like to show that in Desktop Also it will be nice if you say me how to change the icon sets   Recent Updates   I have customized Ubuntu 10.10 with Firefox shortcuts and few folders on desktops. Everything went smooth. But the installer gets crashes after choosing the timezone. How do i fix this issue? Also setting wallpaper affects the login screen. The wallpaper which i set is displayed on the login screen also. I just want the default one for the login screen. I basically need to highlight a particular word in a block of text. For example, pretend I wanted to highlight the word &quot;dolor&quot; in this text: &lt;p&gt;     Lorem ipsum dolor sit amet, consectetuer adipiscing elit. &lt;/p&gt; &lt;p&gt;     Quisque bibendum sem ut lacus. Integer dolor ullamcorper libero.     Aliquam rhoncus eros at augue. Suspendisse vitae mauris. &lt;/p&gt;  How do I convert the above to something like this: &lt;p&gt;     Lorem ipsum &lt;span class=&quot;myClass&quot;&gt;dolor&lt;/span&gt; sit amet, consectetuer adipiscing elit. &lt;/p&gt; &lt;p&gt;     Quisque bibendum sem ut lacus. Integer &lt;span class=&quot;myClass&quot;&gt;dolor&lt;/span&gt; ullamcorper     libero. Aliquam rhoncus eros at augue. Suspendisse vitae mauris. &lt;/p&gt;  Is this possible with jQuery? Edit: As  , this is quite possible without jQuery - but I was hoping there might be a special method of jQuery which would let you do selectors on the text itself. I'm already using jQuery heavily on this site, so keeping everything wrapped up in jQuery would make things perhaps a bit more tidy. How do I parse command line arguments in Bash? Make specific author bold using biblatex Pressing "W" turned my cursor into a circle How can I get the size of an array from a pointer in C? Characterization of short exact sequences The following is the first part of Proposition 2.9 in "Introduction to Commutative Algebra" by Atiyah &amp; Macdonald.     Let $A$ be a commutative ring with $1$. Let $$M' \overset{u}{\longrightarrow}M\overset{v}{\longrightarrow}M''\longrightarrow  0\tag{1} $$ be sequence of $A$-modules and homomorphisms. Then the sequence (1) is exact if and only if for all $A$-modules $N$, the   sequence  $$0\longrightarrow \operatorname{Hom}(M'', N)  \overset{\overline{v}}{\longrightarrow}\operatorname{Hom}(M,  N)\overset{\overline{u}}{\longrightarrow}\operatorname{Hom}(M', N)  \tag{2} $$ is exact.   Here, $\overline{v}$ is the map defined by $\overline{v}(f)=f\circ v$ for every $f\in\operatorname{Hom}(M'', N)$ and $\overline{u}$ is defined likewise.   The proof one of direction, namely $(2)\Rightarrow (1)$ is given in the book, which I am having some trouble understanding. So assuming (2) is exact sequence, the authors remark that "since $\overline{v}$ is injective for all $N$, it follows that $v$ is surjective". Could someone explain why this follows?  Given that $\overline{v}$ is injective, we know that whenever $f(v(x))=g(v(x))$ for all $x\in M$, we have $f=g$. I am not sure how we conclude from this surjectivity of $v$.  Thanks! What is $\int_0^1\frac{x^7-1}{\log(x)}\mathrm dx$?