Recently I've seen in domestic match there was one bowler (spinner) who used his both hands while delivering the ball?  I've doubt can it be possible in International Cricket.  Does ICC has any rule about this?
In the current era of cricket, we see batsmen using switch hits to play a ball. That is, while playing a ball they change their batting side (left to right handed and vice versa) just before the ball comes to them.  My question is, can a bowler bowl a switch ball? Meaning, can a left hand bowler bowl right handed to a batsman? If it is not permitted, then is it not unfair to the bowlers that batsmen can change their batting style but not the bowlers? Or are there are any rules against a switch hit?
Why we can't implement AES 512 key size? Calculating ratio between "rows" in ArcGIS field calculator I have a problem similar to  but that is for QGIS whereas I have to perform it in ArcGIS. I have to calculate the Ratio between rows (sequentially, i.e., row1/row2, row2/row3 and so on) of a specific field based on the ID field and have to assign the results to a separate field. Here is the code and the error message:  def CalcRatio(ID,Frequency):     vDict = {}     with arcpy.da.SearchCursor(&quot;Test&quot;,['Frequency'],'ID = {}'.format(ID)) as sCur:     for Row in sCur:     vDict[Row[0]]=Row[1] # Dict[id] =Frequency     try: value = ( vDict[1] / vDict[2])     except: value = -1     return value  Message: ERROR 000539: Error running expression: CalcRatio( 1 , 50680) Traceback (most recent call last): File &quot;&lt;expression&gt;&quot;, line 1, in &lt;module&gt; File &quot;&lt;string&gt;&quot;, line 5, in CalcRatio IndexError: tuple index out of range  Here is the data OID Id  Frequency 0   1   50680 1   2   49740 2   3   48620 3   4   48300 4   5   48004 5   6   45600 6   7   44384 7   8   42720 8   9   41890 9   10  39700 10  11  38530 11  12  38207 12  13  38106 13  14  37303 14  15  37205 15  16  36527 16  17  35301 17  18  31674 18  19  28890 19  20  24612 Two envelope problem revisited I was thinking of this problem.  I believe the solution and I think I understand it, but if I take the following approach I'm completely confused. Problem 1:  I will offer you the following game. You pay me \$10 and I will flip a fair coin. Heads I give you \$5 and Tails I give you \$20. The expectation is \$12.5 so you will always play the game.  Problem 2:  I will give you an envelope with \$10, the envelope is open and you can check. I then show you another envelope, closed this time and tell you: This envelope either has \$5 or $20 in it with equal probability. Do you want to swap? I feel this is exactly the same as problem 1, you forgo \$10 for a \$5 or a \$20, so again you will always switch.  Problem 3:  I do the same as above but close the envelopes. So you don't know there are $10 but some amount X. I tell you the other envelope has double or half. Now if you follow the same logic you want  to switch. This is the envelope paradox.  What changed when I closed the envelope?? EDIT: Some have argued that problem 3 is not the envelope problem and I'm going to try and provide below why I think it is by analysing how each views the game. Also, it gives a better set up for the game. Providing some clarification for Problem 3: From the perspective of the person organising the game:  I hold 2 envelopes. In one I put \$10 close it and give it to the player. I then tell him, I have one more envelope that has either double or half the amount of the envelope I just gave you. Do you want to switch? I then proceed to flip a fair coin and Heads I put \$5 in and Tails I put \$20. And hand him the envelope. I then ask him. The envelope you just gave me has twice or half the amount of the envelope you are holding. Do you want to switch?  From the perspective of the player:  I am given an envelope and told there is another envelope that has double or half the amount with equal probability. Do I want to switch. I think sure I have $X$, hence $\frac{1}{2}(\frac{1}{2}X + 2X) &gt; X$ so I want to switch. I get the envelope and all of a sudden I am facing the exact same situation. I want to switch again as the other envelope has either double or half the amount. Efficiently finding two squares which sum to a prime Why is the observable universe so big? The observable universe is approximately 13.7 billion years old. But yet it is 80 billion light years across. Isn't this a contradiction? What's the difference between convolution and crosscorrelation? What's the difference between convolution and crosscorrelation? So why do you use '-' for convolution and '+' for crosscorrelation? Why do we need the "time reversal on one of the inputs" when doing convolution? Recurrence relation for the determinant of a tridiagonal matrix Let  $$f_n := \begin{vmatrix} a_1 &amp; b_1 \\ c_1 &amp; a_2 &amp; b_2 \\ &amp; c_2 &amp; \ddots &amp; \ddots \\ &amp; &amp; \ddots &amp; \ddots &amp; b_{n-1} \\ &amp; &amp; &amp; c_{n-1} &amp; a_n \end{vmatrix}$$  Apparently, the determinant of the tridiagional matrix above is given by the recurrence relation   $$f_n = a_n f_{n-1} - c_{n-1} b_{n-1}f_{n-2}$$  with initial values $f_0 = 1$ and $f_{-1} = 0$ (according to Wikipedia). Can anyone please explain to me how they came to this recurrence relation?  I don't really understand how to derive it. Divergence of $\vec{F} = \frac{\hat{\mathrm{r}}}{r^{2}}$ Consider the vector field $$\vec{\mathrm{F}} = \frac{\hat{\mathrm{r}}}{r^{2}},$$ then the divergence of this field is: $$\vec{\nabla}\cdot\left(\frac{\hat{\mathrm{r}}}{r^{2}}\right) = 4\pi\delta^{3}(\mathrm{\vec{r}})$$  What is the proof of this relation? In PHP you can do:  print_r($var) or vardump($var)   which prints "human-readible" information about variable.  Is there equivalent functions / helpers for those in Ruby / Rails ? How to make a good glow effect around a sun? I am a dual Australian/British citizen with an expired emergency Aussie passport and a valid UK passport. What are my chances for an Aussie visit? I was going to have to miss my brother's wedding on Jan 4th but he bought me a flight today. But my Aussie passport is expired and was only an emergency passport to begin with. I'm born and bred Aussie, just been away for ten years. I'm hoping to arrive on UK passport, show the expired Aussie one and the wedding invite and my return ticket for two weeks later and hope they understand.   What are my chances? Also planning on going to the Aussie embassy on Monday to see what they say but want to know my chances of just entering on a UK passport. How do I find the privileges I have earned and will earn in Stack Overflow? It used to be off the top bar, now its gone  Where has it moved?  EDIT:  It moved onto the profile page !  Right side same row as your name in profile:    Thank you Why was the universe in an extraordinarily low-entropy state right after the big bang? Let me start by saying that I have no scientific background whatsoever. I am very interested in science though and I'm currently enjoying Brian Greene's The Fabric of the Cosmos. I'm at chapter 7 and so far I understand most of general ideas he has talked about. Or at least, I think I understand them :-)  There is however one part, at the end of chapter 6 that I can't grasp.  It is about entropy and the state of the universe a few minutes after the big bang.  On page 171 he says:     Our most refined theories of the origin of the universe -our most refined cosmological theories- tell us that by the time the universe was a couple of minutes old, it was filled with a nearly uniform hot gas composed of roughly 75 percent hydrogen, 23 percent helium, and small amounts of deuterium and lithium. The essential point is that this gas filling the universe had extraordinarily low entropy.   And on page 173-174:     We have now come to the place where the buck finally stops. The ultimate source of order, of low entropy, must be the big bang itself. In its earliest moments, rather than being filled with gargantuan containers of entropy such as black holes, as we would expect from probabilistic considerations, for some reason the nascent universe was filled with a hot,   uniform, gaseous mixture of hydrogen and helium. Although this configuration has high entropy when densities are so low that we can ignore gravity, the situation is otherwise when gravity can't be ignored; then, such a uniform gas has extremely low entropy. In comparison with black holes, the diffuse, nearly uniform gas was in an extraordinarily low-entropy state.   In the first part of the chapter Brian Greene explains the concept of entropy with tossing the 693 pages of War and Peace in the air.  At first, the pages are ordered. The specific order they are in make sense and are required to recognize the pages as a readable book called War and Peace. This is low entropy. It is very highly ordered and there is no chaos.  Now, when you throw the pages in the air, let them fall and then pick them up one by one and put them on top of each other, the chances you get the exact same order as the initial state are extremely small. The chance you get another order (no matter what order, just not the one from the beginning) is extremely big. When the pages are in the wrong order, there is high entropy and a high amount of chaos. The pages are not ordered and when they are not ordered you would not notice the difference between one unordered state and another one.  However, should you swap two pages in the ordered, low entropy version, you would notice the difference.  So I understand low entropy as a highly ordered state with low chaos in which a reordering of the elements would be noticeable.  I hope I'm still correct here :-)  Now, what I don't understand is how a uniform mixture of hydrogen and helium can by highly ordered? I'd say you wouldn't notice it if some particles traded places. I'd say that a uniform mixture is actually in a state of high entropy because you wouldn't notice it if you swapped some hydrogen atoms.  Brian Greene explains this would indeed be the case when gravity plays no important role, but that things change when gravity does play a role; and in the universe right after the big bang, gravity plays a big role.  Is that because a reordering of the particles would change the effects of gravity? Or is there something else that I'm missing here? When is a gerund supposed to be preceded by a possessive adjective/determiner? When training a neural network using the back-propagation algorithm, the gradient descent method is used to determine the weight updates. My question is: Rather than using gradient descent method to slowly locate the minimum point with respect to a certain weight, why don't we just set the derivative $\frac{d(\text{Error})}{dw}=0$, and find the value of weight $w$ which minimizes the error? Also, why are we sure that the error function in back-propagation will be a minimum? Can't it turn out the error function is a maximum instead? Is there a specific property of the squashing functions that guarantees that a network with any number of hidden nodes with arbitrary weights and input vectors will always give an error function that has some minima? Embedding DLLs in a compiled executable Is it possible to embed a pre-existing DLL into a compiled C# executable (so that you only have one file to distribute)? If it is possible, how would one go about doing it?  Normally, I'm cool with just leaving the DLLs outside and having the setup program handle everything, but there have been a couple of people at work who have asked me this and I honestly don't know. A correct preposition - account closed due/by/at 12th of May Every principal ideal domain satisfies ACCP. I am about to sell my old desktop PC and I am cautious about some of my sensitive information being available to the purchaser, even after reformatting the hard-drive, using data recovery software.  How can I securely wipe the hard drive so that the data on it cannot be recovered?  Although I specifically want help with my Windows PC, it wouldn't hurt if there were suggestions for Macs as well. Deploying a static site on AWS EC2/nginx: what am I doing wrong?