I've heard that exposing database IDs (in URLs, for example) is a security risk, but I'm having trouble understanding why.  Any opinions or links on why it's a risk, or why it isn't?  EDIT: of course the access is scoped, e.g. if you can't see resource foo?id=123 you'll get an error page. Otherwise the URL itself should be secret.  EDIT: if the URL is secret, it will probably contain a generated token that has a limited lifetime, e.g. valid for 1 hour and can only be used once.  EDIT (months later): my current preferred practice for this is to use UUIDS for IDs and expose them. If I'm using sequential numbers (usually for performance on some DBs) as IDs I like generating a UUID token for each entry as an alternate key, and expose that.


About the integral of $\frac{\sin(ax)}{e^{2\pi x}-1}$ over the positive real line

How could I compute the following integral: $$\int\limits_0^\infty  {{{\sin (ax)} \over {{e^{2\pi x}} - 1}}dx} $$ ? Thank you.


Exit from script if SSH prompts for password

I am trying to achieve a scenario where I need to  SSH to ABC server from XYZ server. Public keys will set up already to smooth password less login. Now i just want to exit from script if found that  SSH command prompts for password. It means  public key are not set up.  ssh -o ConnectTimeout=10 user@ABC <<HERE ----- doing some stuff here---- HERE   Ouput-  Password:   Script resides on XYZ. I am running it from XYZ and trying to SSH ABC. If it prompts for password then exit from script by printing a message.


Why does this regex fails in Python and is successful on regex101?

I have the follwing Python code  import re  regex = r"SRC=(?P<src_ip>[\d\.]*).*?PROTO=(?P<proto>\w*).*?(SPT=(?P<src_port>\d*).*?DPT=(?P<dst_port>\d*)|TYPE=(?P<icmp_type>\d*).*?CODE=(?P<icmp_code>\d*))" input = "<4>Nov 25 12:00:13 ubuntu kernel: [  574.036758] iptableslogIN=enp0s3 OUT= MAC=44:85:00:ec:eb:2b:00:21:55:ef:8c:7f:08:00 SRC=10.24.136.232 DST=10.23.85.76 LEN=44 TOS=0x00 PREC=0x00 TTL=52 ID=5250 PROTO=TCP SPT=56325 DPT=55 WINDOW=1024 RES=0x00 SYN URGP=0" m = re.match(regex, input) print(m.groupdict())   which fails with a   Traceback (most recent call last):   File "C:/scratches/scratch.py", line 6, in <module>     print(m.groupdict()) AttributeError: 'NoneType' object has no attribute 'groupdict'   because input was not matched.  The exact same regex and input is . Why?


I wrote a simple program in JAVA having 4 classes:  Main - > CarFaxApp  GUI / Logic - > CarFaxFrame  Object -> Car  Validator -> CarFaxValidator  Once the program is running and I start to enter the necessary data in the textbox's for the car (String vin, String make, String model, int year). Everything works fine, but when I hit buttonADD(), I get a error.  private HashMap<String,Car>hmCar; //Hashmap to hold Cars, the key pair value consists of (Vin, Car Object)  The error happens on hmCar.put(car.getVin(), car); which I dont understand why, I tried debugging up to the point and car does hold the correct values.  Here a screen shot of the error:


the linear transformation with Rank(T) <n

If $T:V\mapsto V$ is a linear transformation, such that $\operatorname{Rank}(T) < n$, where $n$ is the dimension of $V$. Prove that $\det(T)=0$.


How does the British-Irish Visa Scheme (BIVS) work?

I am an Indian citizen and have applied for the Standard Visitor visa to the UK, and wish to travel to Ireland by using the BIVS scheme.    Do I need to fill up a separate application for BIVS endorsement or is it handed out automatically?  Also, If I enter the UK, and then travel to Ireland, can I re-enter the UK again?


I have to show no proper intermediate fields exist between $Z_2$ and $GF(2^3)$

I have to show no proper intermediate fields exist between $Z_2$ and its overfield $GF(2^3)$, Can any one help?


"Jesus is a coming" - what's the exact grammatical role of the "a" before the gerund?

I've noticed that in the common use of English, namely in songs, there is also an extra redundant(?) "a" before a gerund, such as in a gospel song I heard     Jesus is a coming   (this particular phrase looks like ).  What's the exact grammatical role of this extra inserted a? Is it the indefinite article? Why is it there? Is there any specific reason for it, or is it just bad language, slang or what? Has it developed from a pause in the speech when the speaker needed an extra time to find the word? Something like this:     Jesus is a... what the hell is he.. well, coming!   ADDED:  Based on a comment I am supposed to spell it as     Jesus is a-coming   so maybe you may comment on this, too.


How does murder interact with a creature being sacrificed?

if I cast  on my opponent's creature that has a tap to sacrifice creature after he uses it's ability, does the activated ability happen?  My friends and I had a game where one of them used a tap ability to sacrifice this creature to deal 2 damage and I played .  In response does my creature die or his ability not go off since the sacrifice was not a part of the cost?


Why are House Elves all deemed to be servants or slaves to Wizards?

How come House Elves in the world of Harry Potter (such as Winky, Kreacher and even Dobby) are forced to work as servants to Wizarding families?


limit of a sequence with $\pi $ and $ e $

Let $$ a_n = \frac{n}{\pi}sin(2\pi e n!)  $$ Find $$\lim_{n\to\infty}a_n $$ I tried expanding using the Taylor series representation of $e$ but I arrived nowhere.


Which one is correct - "Committed to help .." or "Committed to helping .."?

Consider "I'm committed to help somebody to do something/with something." vs. "I'm committed to helping somebody. to do something/with something."


Stack Exchange websites should have a fixed topbar so that it scrolls with the page

The entire topbar should be fixed so that it scrolls down with the page.  Why is this not a duplicate of : I am asking we should have this functionality, I'm not looking for workarounds. This is both, a discussion and a feature-request.  People complain that it can be noisy. I disagree. For example, check this image. I just added two styles (position: fixed and width: 100%) and it doesn't look any noisy, but better. It's around 35px and has just six icons: not much noise, and just think what the fixed search bar can do! It can be really helpful.     When scrolling down, you can "warp back" by pressing the Home button, but there's a reason why a lot of websites use this functionality. It will help when reading long texts, especially when you're being active on multiple SE websites and/or questions. It'll notify you of comments, answers, rep changes, etc. in real time when you're focussing on multiple SE websites and/or questions. As of now, you have to finish one page and then scroll all up to find any comments or answers on other questions.   We might skip this for mobile versions and smartphone apps of StackExchange.


Oracle 12c Installation (Grid) on RHEL 7.1 CLSRSC-214: Failed to start 'ohasd'

root.sh script execution failing with following error please advice  ./root.sh Performing root user operation for Oracle 12c  The following environment variables are set as:     ORACLE_OWNER= grid     ORACLE_HOME=  /u01/app/grid/product/12.1.0/grid  Enter the full pathname of the local bin directory: [/usr/local/bin]: The contents of "dbhome" have not changed. No need to overwrite. The contents of "oraenv" have not changed. No need to overwrite. The contents of "coraenv" have not changed. No need to overwrite.   Creating /etc/oratab file... Entries will be added to the /etc/oratab file as needed by Database Configuration Assistant when a database is created Finished running generic part of root script. Now product-specific root actions will be performed. Using configuration parameter file: /u01/app/grid/product/12.1.0/grid/crs/install/crsconfig_params LOCAL ADD MODE Creating OCR keys for user 'grid', privgrp 'oinstall'.. Operation successful. LOCAL ONLY MODE Successfully accumulated necessary OCR keys. Creating OCR keys for user 'root', privgrp 'root'.. Operation successful. CRS-4664: Node lrma086 successfully pinned. 2015/10/22 01:39:44 CLSRSC-330: Adding Clusterware entries to file '/etc/inittab'  2015/10/22 01:41:50 CLSRSC-214: Failed to start 'ohasd'  Failed to start the Clusterware. Last 20 lines of the alert log follow: 2015-10-22 01:39:34.970: [client(21726)]CRS-2101:The OLR was formatted using version 4. 2015-10-22 01:39:39.368: [client(21753)]CRS-1001:The OCR was formatted using version 4.  2015/10/22 01:41:50 CLSRSC-318: Failed to start Oracle ohasd service  Died at /u01/app/grid/product/12.1.0/grid/crs/install/crsinstall.pm line 2985. The command '/u01/app/grid/product/12.1.0/grid/perl/bin/perl -I/u01/app/grid/product/12.1.0/grid/perl/lib -I/u01/app/grid/product/12.1.0/grid/crs/install /u01/app/grid/product/12.1.0/grid/crs/install/roothas.pl ' execution failed


So, I've gotten the candy from the drop game, and I know what it does (allows you to view previous answers by friends). I plan on using it to see more of my friends questions (right now I can only see 2 from each friend) but I can't figure out how to use it. Anyone know how?


I know this types of error already has been answered. But i am not able figure out the cause of error. what i am trying to accomplish is to add button dynamically into fragment from a button click which is in main activity. please help me. i am new to android development,  public class MainActivity extends AppCompatActivity {  Button add; Fragment f; LinearLayout ll; View v;  @Override protected void onCreate(final Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);     add = (Button) findViewById(R.id.addButton);      add.setOnClickListener(new View.OnClickListener() {          @Override         public void onClick(View v) {             f = (ButtonFragment) getFragmentManager().findFragmentById(R.id.buttonLayout);             //if (f != null) {                 v = f.getView();                 ll = (LinearLayout) v.findViewById(R.id.buttonLayout);                 Button dummy = new Button(v.getContext());                 LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(70, 70);                 dummy.setLayoutParams(layoutParams);                 ll.addView(dummy);             //} else {               //  System.out.println("View is null");             //}          }     }); }   }   This is the fragment class  public class ButtonFragment extends Fragment {   @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {     View rootView = inflater.inflate(R.layout.fragment_button, container, false);     return rootView; } @Override public void onViewCreated(View view, Bundle savedInstanceState) {    System.out.println("View created"); } }   this are the error code     11-25 23:15:15.442 987-987/com.example.nekib.dynamiclayoutdemo   E/AndroidRuntime: FATAL EXCEPTION: main                                                                                Process: com.example.nekib.dynamiclayoutdemo, PID: 987                                                                                java.lang.NullPointerException: Attempt to invoke virtual method   'android.view.View android.app.Fragment.getView()' on a null object   reference                                                                                at   com.example.nekib.dynamiclayoutdemo.MainActivity$1.onClick(MainActivity.java:33)                                                                                at android.view.View.performClick(View.java:4780)                                                                                at android.view.View$PerformClick.run(View.java:19866)                                                                                at android.os.Handler.handleCallback(Handler.java:739)                                                                                at android.os.Handler.dispatchMessage(Handler.java:95)                                                                                at android.os.Looper.loop(Looper.java:135)                                                                                at android.app.ActivityThread.main(ActivityThread.java:5254)                                                                                at java.lang.reflect.Method.invoke(Native Method)                                                                                at java.lang.reflect.Method.invoke(Method.java:372)                                                                                at   com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)                                                                                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)


Film where a dropout takes drugs to fight demons

I'm looking for a weird film with people using drugs in order to access some kind of super power to fight evil.    My brain cannot put a title on it because the title was not related to the movie, and the only description of the movie I can think of is, "shooting up wasabi, fighting a frozen chicken meat demon, matrix dodges, gunfire, arachnids, the end of the world, a dog catches the ball, the end".  The dog catching the ball was an important part of the movie, or perhaps eating it.   I saw it around 2008. It was Direct to DVD, not a theater film, a . Psychedelic.   If Raoul Duke (Johnny Depp) from Las Vegas Parano took drugs after reading H. P. Lovecraft, with The Matrix playing on the TV, while he was petting his dog, the dream that would result would be the movie.


Find the limit of the sequence {$a_{n}$, given by

Find the limit of the sequence {$a_{n}$}, given by$$ a_{1}=0,a_{2}=\dfrac {1}{2},a_{n+1}=(1+a_{n}+a^{3}_{n-1}), \ for \ n \ > \ 1$$  My try:  $ a_{1}=0,a_{2}=\dfrac {1}{2},a_{3}=\dfrac {1}{2},a_{4}=0.54$ that is the sequence is incresing and each term is positive. Let the limit of the sequence be $x$. Then $ \lim _{n\rightarrow \infty }a_{n+1}=\lim _{n\rightarrow \infty }a_{n}=x$ $$ \lim _{n\rightarrow \infty }a_{n+1}= \lim _{n\rightarrow \infty }1+a_{n}+a^{3}_{n-1}$$  $\Rightarrow x=\dfrac {1}{3}( 1+x+x^3)$  $\Rightarrow x^3-2x+1=0$  and this equation has three roots $x=\dfrac {-1\pm \sqrt {5}}{2},1$   So the limit of the sequence is $\dfrac {-1 + \sqrt {5}}{2}$.  What is the other way to find the limit of the sequence?


If $e=\lim\limits_{x\to \infty} (1+x^{-1})^x$, why doesn't $e=1$?

I'm sure that this is a very basic question, but it has been bothering me for a while:  If $e=\lim\limits_{x\to \infty} (1+x^{-1})^x$, shouldn't $e=1$?  If $x$ is tending towards infinity, why wouldn't $x^{-1}$ tend to $0$ and $e=1^\infty=1$?  Thanks


Rotating rod - Why can't it reach the speed of light?

$v=\omega * r$, so with $\omega = 1 rad/s$ and $r=3*10^8 m$ the v would be c. I know that the information of the rotation travels with the speed of sound in the rod.


Should I use reference manager software?

Should I use software for managing my references?  What is the benefit of it?   I can write down the references by myself, so I'm not sure what the benefit is.


What is the best method for exchanging dollars for Euros?

I'm traveling from the US to Europe in a few weeks.  When and what is the best method of exchanging dollars for Euros?    I imagine there's options like:   at the airport when you arrive in Europe at a bank in the US before you leave at a bank in Europe upon arriving


Everytime I use the Ellipse tool in photoshop it creates a border with a black fading to grey outline.    I want to make an ellipse with a solid black outline with zero gray colors instead.


I saw a math symbol looks like this, anyone know what does it stands for? $$-V^t + G[D^T]^+$$


How to create a $N \times N$ matrix with $1$ and $-1$ as its elements, such that when this matrix is multiplied with its transpose the resultant matrice is $N \times \mathbb{I}_N$. Where $N$ is a scalar and $\mathbb{I}_N$ is the $N \times N$ identity matrix. Examle for 2x2 matrix $-1$ $1$ $1$ $1$  Example for 4x4 matrix $-1$ $1$ $1$ $1$  $1$ $-1$ $1$ $1$  $1$ $1$ $-1$ $1$  $1$ $1$ $1$ $-1$


Check if $\sum_{n=0}^\infty \frac{\sin(n)}{n}$is convergent.  I have elaborated on this question for a while and I have come up with an answer - yes, it is convergent. First, let's say that $$a_n= \frac{1}{n}$$ We can infer that $\lim a_n = 0$ and that $a_1 >a_2 > a_3> \dots$  Now, consider $$b_n = \sin(n)$$ $$\sum_{n=0}^{\infty} sin(n)$$ is clearly bounded, although I don't know how to prove it. (Any suggestions would be most welcome).   And so my reasoning has reached the seminal point - by virtue of Abel theorem - the series in question is clearly bounded. Is it correct?


Is an article required before a math variable?

Is the definite article required before a variable used to abbreviate a physical quantity?  The ft is the same for both cases at various values of the Lc. As the Lc increases, the fr  also shifts.   ft is the same for both cases at various values of Lc. As Lc increases, fr  also shifts.  If the second sentence is okay, I am still a bit weirded out by starting a sentence with a math notation. (Lc = Length of the channel, ft = frequency of the transistor)


How do American English and British English use the definite article differently?

I decided to make sure that I know this important difference between American and British English, so I wrote what I have found out so far and I would be grateful to anyone who reads this and tells me whether I am wrong, or not.  In British English when people say  to hospital or in hospital when  talking  about somebody being there as a patient they don't use the definite article : "I had to go to hospital", "She spent two weeks in hospital". And the meaning is that somebody was there as a patient.   If then for some other reasons British English speakers  will use the definite article which will change the meaning itself, I noticed that, in American English, native speakers often use the  the and if they need to show that somebody is in church to pray,  in school as a student, in hospital as a patient, in prison as a prisoner, they use 'in' and not 'at'. Do American English speakers use 'at' like British English speakers use 'the' to give the sentences a different meaning?    Are my sentences correct? Do they show American English usage?   He is in the school. (enrolled as a student) He is at the school. (for some different reasons) He is in the hospital. (as a patient) He is at the hospital. (visiting somebody) He is in the church. (to pray) He is at the church. (for some different reasons) He is in the university. (as a student) He is at the university. (not as a student) He is in the college. (as a student) He is at the college. (Not as a student) He is in the prison. (as a prisoner) He is at the prison. (not as a prisoner)


Install Apache, Php, Mysql latest versions not available via apt

I need to install the latest versions of apache, php and mysql that are available on their websites, but the problem is that apt repositories don't have these updates versions yet.   Versions that I want: Apache 2.4.4, PHP 5.4.16 and MySQL 5.6.12.  Versions available via apt: Apache 2.2.22, PHP 5.4.15, MySQL 5.5.31.  Ubuntu doesn't support the above versions of packages. Please, I want help! Thanks!  P.S. Tasksel also doesn't have these versions of packages yet.


Move image files according to watermark identified by a neural networks

I have created a neural network that can identify watermarks and can classify them to which company do they belong. Now I created a script that will identify watermark from a folder and move them to different folders where they belong. But this script is quite slow and consumes too much RAM. What should I do to improve it?  from keras.preprocessing.image import img_to_array from keras.models import load_model import numpy as np import argparse import imutils import pickle import cv2 import os import time  import glob import shutil import csv d = glob.glob("colabData/Krishna/*.jpg") print("Total Number of Images are :" ,len(d))  count = 0 final_data = [] def convertToRGB(img):      return cv2.cvtColor(img, cv2.COLOR_BGR2RGB)  for images in d:     count += 1     test1 = cv2.imread(images)     sublist = []     output = test1.copy()     image = cv2.resize(test1, (96, 96))     image = image.astype("float") / 255.0     image = img_to_array(image)     image = np.expand_dims(image, axis=0)      model = load_model("colabData/pokedex.model")     lb = pickle.loads(open("colabData/lb.pickle", "rb").read())     proba = model.predict(image)     idx = np.argmax(proba)     label = lb.classes_[idx]     if not os.path.exists(label):         os.makedirs(label)     sublist.append(label)     if label=="Commonfloor":         shutil.move(images, "colabData/commonfloorr")         print("WaterMark is Available", images, label)     elif label=="Housing":         shutil.move(images, "colabData/housingg")         print("WaterMark is Available", images, label)     elif label=="Sulekha":         shutil.move(images, "colabData/sulekhaa")         print("WaterMark is Available", images, label)     elif label=="Magicbricks":         shutil.move(images, "colabData/magicbrickss")         print("WaterMark is Available",images, label)     elif label=="Property_Wala":         shutil.move(images, "colabData/propertywalaa")         print("WaterMark is Available", images, label)     elif label=="Non-Watermark":         shutil.move(images, "colabData/nonwatermarkk")         print("WaterMark is Not Available", images, label)     elif label=="FloorPlans":         shutil.move(images, "colabData/floorplann")         print("WaterMark is Not Available", images, label)     elif label=="MasterPlan":         shutil.move(images, "colabData/masterplann")         print("WaterMark is Not Available", images, label)     else:         print("Unable to classify")     print(count)     final_data.append(sublist)  filename = "data.csv" with open("colabData/"+filename,'w') as csvfile:     csvfile = csv.writer(csvfile, delimiter=',')     csvfile.writerow("")     for i in range(0, len( final_data )):         csvfile.writerow( final_data[i]  )


I am reading the first chapter of Aliprantis and Border's Hitchhiker guide and there is a passage on Russel's paradox that has me confused. It reads:  Russell's Paradox is a clever argument devised by Bertrand Russell as an attack on the validity of the proof of the Diagonal Theorem. It goes like this. Let $S$ be the set of all sets, and let $\varphi:\mathscr{S}\rightarrow\mathscr{S}$ be defined by $\varphi(A)=\{B  \in \mathscr{S}: B \in A\}$ for every $A \in \mathscr{S} $. Since $\varphi(A)$ is just the set of members of $A$, we have $\varphi(A)=A$.  However, if we take $A=\{1,2\}$ then $\varphi(A)=\emptyset$ since $A$ does not contain any sets, which are the elements of $\mathscr S$. Am I missing something? Should $\varphi$ be defined from $2^{\mathscr S}$ to $2^{\mathscr S}$? Thanks!


So I asked a friend to dual-boost ubuntu 14.04 with Windows 8.1. But the USB stick he used to install ubuntu came out. He re-did the install but ubuntu didn't recognise windows and took over the entire laptop. Anyway, about the DVDs. I tried to play a DVD on totem. It didn't work. My brother installed VLC but when I tried to play a DVD on that it said it had to be Eclipse because of a playlist I had accidentally created. With the playlist now gone and a different DVD in the laptop I tried again, to little success. I have done several things in the terminal including libdvdread4 and some other stuff. I removed and installed VLC again to little success. At first it tried to play Sims3 as a DVD so I compressed the file and moved it. This enabled Angel to be read but not play. It has the cone stay on the screen and angel appears on the bar instead of VLC but then VLC comes back.


I know that an op-amp tries to hold the input voltages the same. So, for virtual ground we can connect + node to the ground and we're getting a 0V on the - node. If the op-amp tries to keep the inputs the same, why are we not getting a virtual ground on the + node if we connect - node to ground?


The moment of inertia is a tensor and the  matrix contains nine elements. The off-diagonal elements are like Ixy, Ixz, Iyx and so on. Ixy = mxy.  But M.I. = mass × (perpendicular distance of the particle from the axis)^2. So what does this x×y signify in the relation for Ixy?


Which privileges/settings are responsible so standard user can start a service?

My code works fine on one computer but the same code generates error code 5 (access denied) on another computer. Essentially ::OpenService() call fails because of the flag SERVICE_START because the user doesn't have privileges to start the service. I know because it does start the service if I start the app as administrator.  I want the same privileges on the 2nd computer so any user can start a service but can't figure out which settings is responsible for that. I looked into group policy >> Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> User Rights Assingment.  I don't know if I am even looking at the right place. Does anyone know?


Bag for holding valuables on bike while parked?

I ride regularly in the city with my a few valuables with me. My purse, phone, keys, company ID card etc. I hate having a bag on me while ride so I am looking for a solution to have these few items in a bike bag, but also have them safe if I stop somewhere to run into  a shop or a cafe for 15 minutes.   My original idea was to look for a small saddle or top tube bag that is lockable and also safely locked to the frame, and I can simply leave it there. As it turns out there is no such thing! Or I just did not find it?  My second idea was to search for a similar bag, but which is easily detachable and I can take it with myself as a waist bag for example. Same story, I couldn't find anything like this on the market.  Do you know any bag that could work for me? Or do you have an alternate suggestion for my conundrum?   Thank you very much if you take the time to answer! Ride safe! János


usage of unreal hypothetical when speaking of something unlikely to happen

Is this correct?      When a student asked if he was “a dictator like Hitler,” Patterson asked, “If I was Hitler, does that mean I put you in an oven?”   Isn’t that supposed to be “if I were” there?


What size difference is there between the PSP 1000, 2000 and 3000 for applying Skin Stickers?

I've been looking at some Sword Art Online Skin Stickers but it says that they are meant for the PSP 3000, from the looks of the images the only difference I see between the 2 models is that the metal ring around the back is slightly thinner  So I'm wondering, with the PSP 1000, 2000 and 3000, what differences are there with size that could affect how a Skin Sticker is applied?  .


User can answer to a question marked as duplicate

I was making an answer to a question in SO on (03-Jan-2014) and while I was making my answer I got a pop up saying that this question is closed now....and so on.. And when I checked the POST YOUR ANSWER button it looks like a disabled one.And when I inspected the html of that button its like the following  <input id="submit-button" type="submit" value="Post Your Answer" tabindex="110" disabled="disabled">   So I simply removed the disabled attribute of that element and made it as this  <input id="submit-button" type="submit" value="Post Your Answer" tabindex="110">   which made the element a normal one.Then I completed my answer and posted it. And the answer has posted even if the question was marked as a duplicate. You can check the following link to see the question and its answer    And when you check the question you can see that the answer is posted after 3 mins the question is closed which proves what I stated.


Apparently MSE questions are able to appear in the hot list, which the old MSO didn't managed to. Shouldn't MSE behave the same way as the old MSO in this aspect?


I'm playing Minecraft in Survival, and no hostile mobs are spawning! This has been happening for the past week or so. I also tried Creative mode (superflat) and mobs are spawning there.  What would cause mobs to stop spawning in Survival?  Details:   Minecraft 1.7.2 Using Rei's mini map mod Windows Vista Created a new super flat world (creative) and mobs spawn


Why do i have bald spots with hair particlesystem?

I have a camel mesh, both mirror and subdivision surface modifier applied, with armature on it and I wanted to give it some hair. I added a hair particle system with interpolated children and made a density group, but I have got some bald spots in some areas. I am sure, that I am using correct vertex group to control density, I tried to make some changes in the emission panel in the advanced particle settings. The only way to solve this I found was to make same number of hairs per face, as is the number of faces, but since I have over 12 000 of faces, this isn't quite ideal. here is picture of how it looks: here are the problematic parts of my model:  (so far I know about tail and legs. It isn't whole model, just the parts.)


I'm unable to kill a process using any of the techniques I'm aware of ("Force Quit" in Activity Monitor, top, killall from the Terminal) and wonder if there are some additional steps I can take.    ~ $ sudo killall -KILL 77439 Password: No matching processes were found ~ $ killall -KILL 77439 No matching processes belonging to you were found ~ $ killall 77439 No matching processes belonging to you were found ~ $ killall Mathematica No matching processes belonging to you were found   FWIW the process is "Mathematica" which I cannot relaunch, Quit, or Force Quit, or sample, either by name or PID, and it appears to have some odd side effects (screenshots don't appear, can't empty trash, and can't even shut down the system).  Are there additional steps that can be taken to really really kill a badly behaved process?


Existence of Consecutive Quadratic residues

For any prime $p\gt 5$,prove that there are consecutive quadratic residues of $p$ and consecutive non-residues as well(excluding $0$).I know that there are equal number of quadratic residues and non-residues(if we exclude $0$), so if there are two consecutive quadratic residues, then certainly there are two consecutive non-residues,therefore, effectively i am seeking proof only for existence of consecutive quadratic residues. Thanks in advance.


Installing required packages for Soundwire Server gives weird and horrible output

I was trying to install "SoundWire Server". It requires some additional packages, according to this   I am on Ubuntu GNOME 16.04.  I have tried to install libportaudio2, but I get an error relating to python-cryptography:  $ sudo apt-get install libportaudio2 Reading package lists... Done Building dependency tree        Reading state information... Done libportaudio2 is already the newest version (19+svn20140130-1build1). 0 upgraded, 0 newly installed, 0 to remove and 171 not upgraded. 1 not fully installed or removed. Need to get 0 B/198 kB of archives. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] y  dpkg: error processing package python-cryptography (--configure):   package is in a very bad inconsistent state; you should reinstall it before attempting configuration Errors were encountered while processing: python-cryptography E: Sub-process /usr/bin/dpkg returned an error code (1)   to fix I have tried using  sudo apt-get install --reinstall python-lockfile   but that produced more errors:    I don't know what to do next. I want to install SoundWire because my audio jack isn't working.


I want to put logo at top right corner in beamer, maybe just align with the title line but should not depended on title bar exist or not :-).  For reference, is to put logo at the bottom line.  Current code as below:  \documentclass[t]{beamer} \beamertemplatenavigationsymbolsempty \setbeamertemplate{footline}[frame number] \logo{\makebox[1\paperwidth]{\includegraphics[width=.5cm,keepaspectratio]{logo.png}}}  \begin{document}  \begin{frame}[c]{Hello world} \begin{itemize} \item item 1 \item item 2 \item item 3 \end{itemize} \end{frame}  \end{document}   Current output is:


Why does the definition of convergence have $<\varepsilon$ instead of $\le\varepsilon$?

So the definition of convergence for a real sequence that I'm looking at says that $(a_{n})\to L$ means that $\forall\,\varepsilon>0\,\exists N\in\mathbb{N}:n>N\implies|a_{n}-L|<\varepsilon$.   The book I am reading says some people will say $n>N$ and some will say $n\ge N$, and it doesn't matter. I agree with that part. But what about the $<\varepsilon$? The book made no mention of that, and so I tried to figure out if $\le\varepsilon$ would work too. I feel like there must be a reason it has to be $<\varepsilon$, otherwise it would have been mentioned if they bothered to mention $n>N$ and $n\ge N$.   I thought maybe the problem would be that a lot of points would sit exactly at say, $L+\varepsilon$, but they can't sit there forever since we would be able to make $\varepsilon$ smaller and so they'd still have to get closer to $L$ anyway. Then I thought maybe the problem would be that we get an interval with only one point) like $[2,2]$, and then that would make it so convergence means the sequence's terms have to equal $L$, but since $\varepsilon$ is positive, I don't think the one-element-interval scenario can happen.   Why is $<\varepsilon$ used (or required) to accurately describe what convergence is saying about a sequence, instead of $\le\varepsilon$?   (If anyone has the time, I would greatly appreciate any explanation as to why convergence is something we want to know about a real sequence or why people want to know about limits of real sequences in general so I may be able to appreciate this definition. All I understand so far is that some infinitely long, ordered lists of real numbers get arbitrarily close to a real number and some don't. Sometimes when reading examples it does surprise me what number a sequence converges to or that a sequence doesn't actually get arbitrarily close to a number it seems to get really close to, but this is all the motivation I can think of.)


Why does this excerpt say that unbiased estimation of standard deviation usually isn't relevant?

I was reading on the computation of the unbiased estimation of standard deviation and the source I read stated      (...) except in some important situations, the task has little relevance to   applications of statistics since its need is avoided by standard   procedures, such as the use of significance tests and confidence   intervals, or by using Bayesian analysis.   I was wondering if anyone could elucidate the reasoning behind this statement, for example doesn't the confidence interval use the standard deviation as part of the calculation? Therefore, wouldn't the confidence intervals be affected by a biased standard deviation?  EDIT:  Thanks for the answers so far, but I'm not quite sure I follow some of the reasoning for them so I'll add a very simple example. The point is that if the source is correct, then then something is wrong from my conclusion to the example and I would like someone to point how how the p-value doesn't depend on the standard deviation.  Suppose a researcher wished to test whether the mean score of fifth graders on a test in his or her city differed from the national mean of 76 with a significance level of 0.05. The researcher randomly sampled the scores of 20 students. The sample mean was 80.85 with a sample standard deviation of 8.87. This means: t = (80.85-76)/(8.87/sqrt(20)) = 2.44. A t-table is then used to calculate that the two-tailed probability value of a t of 2.44 with 19 df is 0.025. This is below our significance level of 0.05 so we reject the null hypothesis.  So in this example, wouldn't the p-value (and maybe your conclusion) change depending on how you estimated your sample standard deviation?


Program cant see the correct input, very new to java

Please help, this will be an easy and obvious problem but im new to coding and im teaching myself online. My program should ask the user to enter an amount, it should then ask the user to enter an account type, and it should then output the value of the amount with a years interest.   import java.io.IOException; import java.util.Scanner;   public class BankInvestment {      private static final String Account = null;      public static void main(String[] args) throws IOException {         // TODO Auto-generated method stub         int S = 3;         double D = 0.5;         double C = 1.5;         int L = 4;         @SuppressWarnings("resource")         Scanner input = new Scanner(System.in);         @SuppressWarnings("resource")         Scanner user_input = new Scanner( System.in );         int n = input.nextInt();         int Output = 0;         String Accounttype = null;          System.out.println("Please Enter Account Type(S,D,C,L): ");         Accounttype = user_input.next();          if (Accounttype == "S"){             Output = n / 100 * S + n;             System.out.println(Output);         }         else if (Account == "D"){             Output = (int) (n / 100 * D + n);             System.out.println(Output);         }         else if (Account == "C") {             Output = (int) (n / 100 * C + n);             System.out.println(Output);         }         else if (Account == "L"){             Output = n / 100 * L + n;             System.out.println(Output);         }     } }


An elementary question regarding a multiplicative character over finite fields

Reading Chapter 2 of Koblitz's Introduction to Elliptic Curves and Modular Forms, I got stuck on the following question. I would like to proceed my reading, so I would appreciate any hint to this. I have no background in Algebraic Number Theory, but if someone explains in that language, I would like to see it and learn it as much as I can at this moment. References will also be appreciated!  Let $q$ be a power of prime $p$ such that $q \equiv 1 \mod 4$ and $p \nmid 2n$.  Question. Let $\chi_{4} : \mathbb{F}_{q}^{*} \rightarrow S^{1}$ be the character of order $4$, show that $\chi_{4}(-4) = 1$.  The hint in the book says we may show that $\chi_{4}(4) = \chi_{4}(-1) = 1$ for $q \equiv 1 \mod 8$ and $\chi_{4}(4) = \chi_{4}(-1) = -1$ for $q \equiv 5 \mod 8$.  If $q \equiv 1 \mod 8$, then $\chi_{4}(4) = \chi_{4}(2)^{2} = \chi_{2}(2) = \pm 1$, where $\chi_{j}$ denotes the character of order $j$. So I think $2$ must be quadratic residue in this case, but I cannot figure out why.


Something like Parallels Desktop for Linux?

I'm not normally a fan of mac software implementations, but recently I saw a copy of Parallels Desktop for mac that I was very much impressed by. I looked into parallel's offerings for Linux (I was initially excited that they developed for *nix) but found that it has essentially the same features as VMware.   Does anyone know if there is a software solution for linux that offers the level of integration that the current Parallels Deesktop for mac has?  I looked into wine for the programs I want to run and was very frustrated. I feel like all the ratings in their application database were fabricated honesty. I've tried wine once every Ubuntu release since 8.10 and have never gotten it to work stably.


I'm using Texmaker on Linux Mint 15. I previously used Texmaker on Windows, with the MiKTeX package manager to automatically download required packages for me. Is there a similar tool I can use on Mint?


Technical term for an SE page with question and answers

Which term should be used for subj?   "Question" is ambiguous because it can also mean just the question part. "Thread" is used, too, as per  , but the current discussion shows that it doesn't seem to be accepted by community at large.   The established related terms are as follows:   "answer" and "comment" -- self-descriptive "post" -- a unifying term for the large messages, this is what they are called internally . For an entire page, I don't see such an official term. I also used "question" to denote the "question post": the meaning seems clear if I place it in a context that hints that I'm considering things in the confines of the current page.   This, however, limits its use to such contexts, severely restricting the freedom of expression: I need to think carefully and set things up to help me each time.  Likewise, "another question" is clear about meaning another page. Its use is still limited to where this expression fits.   The best context-free term that I've come up with so far is "(a) Q&A".   It also means an operational model, but it's only used as such in philosophical discussions, which are rare, and it's often used as an expression "the Q&A model" in those. Using an article also shows that it's meant as a countable noun while the "model" meaning is uncountable (in the phrase, it's used as a noun-based adjective AFAICS, "the" is related to "model")   I see that .    The intended use case is:   To refer to a page (either current one or other one(s)), concisely and unambiguously, as a technical object, a building block of the site's content, like other types of pages or parts of a page. Be usable and clear without context -- i.e. not require to adapt the surroundings for it to fit (so phrases constructed from common words likely not qualify -- I'd have to show somehow that I mean it as a term and not as a common phrase)   If the SE staff has an official term they use internally, it will surely be preferrable to any "fan nickname" unless the latter is vastly superior for the specified use.  (I asked the SE team if they have an internal term)  --  To keep things constuctive, please try to heed  (I tried to).


How to get more information about "Error loading extension"?

How do I get more information why a specific extension is not working and showing me "Error loading extension" when trying to enable it?


Is there a way to reference just plain text with the \ref{} tag?  I have a table with two columns. Each column has content which links to a different part below. The reference in the first column is no problem, because it refers to an item. The second column however is just plain text, but I want to refer that to the other text as well. I want to do that, so that I only need to change the referenced text and the text in my table will automatically update (preferably a reference, which can't be clicked on).  Here is the rough outline.  Table  Col 1 | Col 2 \ref{sth:bla} & \ref{sth:text} \   The referenced part  \begin{description}     \item[Something\label{sth:bla}] The Text \hfill \\     Description! \end{description}   So now I would want to reference "The Text" with \ref{sth:text}, so that I wouldn't have to change the text twice. As I said, preferably I would like to reference without actually making if clickable.  The answer given by Werner does work fine to some point. Here is an example, where it doesn't seem to work correctly anymore. How would I use regular referencing in the document now?  \documentclass{article} \usepackage{hyperref}% http://ctan.org/pkg/hyperref \makeatletter     \newcommand*{\textlabel}[2]{%         \edef\@currentlabel{#1}% Set target label         \phantomsection% Correct hyper reference link         #1\label{#2}% Print and store label     } \makeatother \begin{document} \section{A section}  This is a table:  \begin{center} \begin{tabular}{l|l}  Col 1 & Col 2 \\ \ref{sth:bla} & \ref{sth:text} \\ \ref{Blub} & Text \\ \end{tabular} \end{center}   The items:  \begin{description}    \item[\textlabel{Something}{sth:bla}] \textlabel{The Text}{sth:text} \hfill \\    Description! \\    \item[Blub\label{Blub}] Something \hfill \\    Another description! \end{description} \end{document}   The normal reference tag will now be replaced by the text content of the textlabel.


I don't know what the hell happened with my laptop but it just keeps on typing number 6 itself. I tried to disable the key with KeyTweak and many other apps but it didn't worked. I can't type anything properly.  Does anyone know how to fix this?


Exported FBX model looks different from in Blender

When I export my model to FBX I am finding the faces what doesn't exist in Blender project. I mean the faces that cover the actual speaker. They are not hidden, an it actually is on face where I used boolean tool. I don't really know what I might be doing wrong and where to start.


How to add 1 to score if EditText value is true

Good day everyone, so i am writing a quiz app and score is based on what the user selects. I used radio buttons, check box and edit text tags for answering questions. When the user clicks a radio button, or a check box, the score updates, but when the user enters the correct text in the EditText field, the score does not update. I used an if else statement to check if the string entered matches an answer.      public void startFinalScreen(View v) {      EditText text = (EditText) findViewById(R.id.edit_text_view_answer);     int questionNineScore = getIntent().getIntExtra("GNS", 0);     int finalScore = questionNineScore;     String answer = "William Shakespeare";     if (text.getText().toString() == answer) {         qNineScore = qNineScore + 1;     }     finalScore = qNineScore;     }   I used .getIntent() to get score from a previous activity. After i do this, the score does not add +1 even after typing the correct answer.


How to find total number of sum of consecutive number of $n$?

How many ways are there to write $n$ as the sum of consecutive positive integers?   Example: $15$ has $3$ consecutive sums:   $1+2+3+4+5=15$ $7+8=15$ $4+5+6=15$


So far I've been getting a good bit of non-answers by other linux forums for a port (that works) of ubuntu for a Surface RT. I just want a dl link or a detailed walk through on how to make one myself, seeing as I am not a dev. I understand how to install ubuntu, and that's about the extent of my knowledge on the subject.


can't update plugins or wordpress or install new plugins

how to update plugins wordpress how to replace my code in new plugins ?? I have some plugins that need to be updated (as well as WordPress) and I have tried the automatic update button and the update fails. I get an error message "Could not create directory.: /public_html/wp-content/upgrade." I have tried to delete the upgrade folder in cPanel and then create a new one but it won't let me create a new .php file.


Should we apply normalization to test data as well?

I am doing a project on author identification problem. I had applied the tf-idf normalization to train data and then trained a svm on that data.  Now when using the classifier should I normalize test data as well. I feel that the basic aim of normalization is to make the learning algo give more weight to more important features while learning. So once it has trained it already knows which features are important, which are not. So is there any need of applying normalization to test data as well?  I am new to this field. So please ignore if the question appears silly?


Has "the SE Network" been changed to "the SO Network"?

Today as most of you did, I received an email entitled  [Terms of Service and Privacy] What's new  In the last paragraph, I noticed this expression:  Please read these updated terms and take your time to understand these changes. Your use of Stack Overflow's Products and Services, including the Stack Overflow Network, is subject to these revised policies and terms.  From time to time I've learned that the company is named "Stack Exchange Inc." and the Network has been referred to as "the Stack Exchange Network". I expected that in the bold text, it should have been "Stack Exchange". Did the Department of Renaming just come up working?


Looking for Melbourne and Canberra metropolitan suburb shapefiles / ABS coded lists

I am looking for shapefiles or a list of suburb names for Melbourne and Canberra. I have ABS shapefiles, but I need to filter that to end up with only metropolitan suburbs.  My shapefile has codes in it for  - I just need to know which suburbs belong to the metros.


If $0 \lt x \lt \frac{\pi}{2}$, is $\cos(x) \le \frac{\sin(x)}{x} \le \frac{1}{\cos(x)}$?

How can I find the following product using elementary trigonometry?     Suppose $0 \lt x \lt \frac{\pi}{2}$   is an angle measured in radians. Use the trigonometric circle and   show that $\cos(x) \le \frac{\sin(x)}{x} \le \frac{1}{\cos(x)}$.   I have been trying to solve this question. I can't figure out whether or not the solution requires a trigonometric circle or if it can be done using another method.


I've been working on this mushroom to render and the stalk and dome create a seam where there is different materials. Anyone know how to fix this?


Texture doesn't have the texture but only the texture color

I made a landscape in blender but if i use my texture it isn't using the texture but the texture color. Please Help me]


I want to alter the title tag in jquery. tried as $(document).attr("title", "New Title"); but title tag in view source is not altered and changed only in browser title bar.  How to change the title in title tag in jquery   new title


Allow to assign part of a non-OP bounty to the OP

Sometimes a well-posed question appears and makes one really think. And while the original intention of bounties was encouraging others to post an answer that may require above average effort, the option "reward an existing answer" made me think - formulating the question itself may sometimes deserve a reward as well, and not just the "oh yeah, nice question"-upvote - in fact. And while an added bounty may yield additional upvotes by others, I'd still like to propose the implementation of one of the following:     a) The option to award a bounty to the question in addition to answers   b) Part of a bounty awarded to an answer is (optionally) awarded to the question as well   I think option a) is straightforward, although in that case an additional option "reward the question" that is either assigned immediately (so the question doesn't show up in the featured list) or automatically after its expiration (so the question is additionally rewarded by being featured) may be useful. But it should also be possible to award a usual bounty to the question in case no helpful answers appeared.  Option b) could be implement in various ways. One possibility could be that a non-OP bounty causes the question to automatically obtain part of the bounty, say 10%, additionally to the actual bounty, which is not deduced from the bountyee. But it would be better to set this percentage manually, since sometimes one wants to reward an clever answer to a question that doesn't really deserve a bounty as well.


How can I remove the first letter from  a directory name? for example: Folder is named as "AFolder_01" how can I rename it to "Folder_01"  The reason for my question is that I have list of folders and I want to rename all these folders at once by removing the first letter. I found this code online to remove the last character(s):    while IFS= read -r dir; do [[ -d $dir ]] && mv -i "$dir" "${dir%?}"; done <all.txt    How can this code be revised to remove the first letter? i.e. In my example  rename "AFolder_01" to "Folder_01" How can this code be revised to add charterer back at the beginning of the folder name: i.e. in my example rename "Folder_01"  to "AFolder_01"


How to get users (entities) for a certain field value?

I want to write a function that returns users which have entered a certain value to a custom user field.   Lets say there is a custom birthday field for every user. What would be the best way to get all users with a certain birthday?  I could create a DB query that searches the field_data_field_birthday table and returns the entity_id(s) (which in this case would be the users id(s)) for which the field_birthday_value matches a given value and then load the user(s).   This seems a little bit crude, are there generic functions for this use case available? In the entity API or the field API maybe?


Fabric script doesn't printing output on success

import sys from fabric.api import *  env.hosts = ['my.host.com'] env.user = 'myuser' env.password = 'mypassword' # env.shell = '/bin/bash -l -c'  def deploy():     x = run("cd /srv/proj/")     print x.__dict__   I'm trying to login into remote shell and execute this simple cd command. although it shows that there is no error  [my.host.com] run: cd /srv/proj/ {'succeeded': True, 'return_code': 0, 'failed': False, 'command': 'cd /srv/proj/', 'stderr': '', 'real_command': '/bin/bash -l -c "cd /srv/proj/"'}   but when I execute run('ls') after cd command, it prints nothing but definitely there are files. so what is happening here. apart from that I'm having issues in executing manually set command (i mean alias in .bashrc file). fabric uses /bin/bash -l -c .... how can I overcome this hurdles.  I'm using ubuntu 14.04   ps: it's not same as os.chdir


Generate multiple variants of a figure using tikz and standalone

I use TikZ with the standalone document class to generate figures for a presentation using , i.e. outside of LaTeX. Some of these figures undergo a few animation steps, which require little modification to the source code. I would like to automate the generation of all variants. Is there a LaTeX-only way to generate multiple output files in a single run? I have used a python script that repeatedly runs LaTeX and modifies the source in-between, but I would prefer a one-file solution. Could TikZ's externalize library help here?


No maximum(minimum) of rationals whose square is lesser(greater) than $2$.

Suppose $A$ is the set of all rational numbers $p$ such that $p^2 <2$ and $B$ is the set of all rational numbers $p$ such that $p^2 > 2$. We want to show that $A$ contains no largest element and $B$ contains no smallest element.  In Rudin's Principles of Mathematical Analysis, he associates $q = p- \frac{p^2-2}{p+2} = \frac{2p+2}{p+2}$. Did he just come up with this using trial and error?


How to calculate $\,(a-b)\bmod n\,$ and $ {-}b \bmod n$

Consider the following expression:  (a - b) mod N   Which of the following is equivalent to the above expression?  1) ((a mod N) + (-b mod N)) mod N  2) ((a mod N) - (b mod N)) mod N   Also, how is (-b mod N) calculated, i.e., how is the mod of a negative number calculated?  Thanks.


Why would Google Search Console report many times more indexed URLs than a Screaming Frog crawl finds?

I've just crawled my website in Screaming Frog and I have around 6K Internal URLs and 4K external URLs. Then I looked in GSC and saw that Google indexed 50K pages.   How is that possible?


What Open Source Packages are available to provide routing?

I am looking for ways to validate mileage charged by our contractors.  They are paid from a central location to a customer, and then from the customer to a drop off location.    I use QGIS for a bunch of stuff and also have access to MapInfo Pro.     I need to do the following:        route individual trips to get total distance in each direction   also need to know if parts of one trip overlap the other, and by how much (i.e. km)    and if the second trip ends anywhere along the route of the first trip (i.e. they came back the same way they went out)       I have been messing around with PostgreSQL and pgRouting for a couple days and it's pretty confusing to me.


SElinux: allow httpd to connect to a specific port

My system is running CentOS 6.4 with apache2.2.15. SElinux is enforcing and I'm trying to connect to a local instance of redis through my python/wsgi app. I get Error 13, Permission denied. I could fix this via the command:  setsebool -P httpd_can_network_connect  However, I don't exactly want httpd to be able to connect to all tcp ports. How can I specify which ports/networks httpd is allowed to connect to? If I could make a module to allow httpd to connect to port 6379 ( redis ) or any tcp on 127.0.0.1, that would be preferable. Not sure why my paranoia is so strong on this, but hey...  Anyone know?


Does the CP of a caught pokemon result in a different max CP?

If I catch for example a pidgey at CP 10 and then power him up to max, would his CP be better or the same as a pidgey that I caught at 150CP and powered up as much as possible?


How to remove all accents from json file in python

I'm importing a json file in python, but the file is full with accent characters in the city name (from portuguese language) and I need to somehow remove then from this file to further use. For example, the words 'São Paulo', 'Santo André' and 'Foz do Iguaçu' should become in the json: Sao Paulo, Santo Andre and Foz do Iguacu.     { "type": "FeatureCollection", "features": [          { "type": "Feature", "properties": {"id": "1100015", "name": "São Paulo", "description": "Alta Floresta D'Oeste"}, "geometry": { "type": "Polygon", "coordinates": [-62.1820888570, -11.8668597878] }},         { "type": "Feature", "properties": {"id": "1100023", "name": "Santo André", "description": "Ariquemes"}, "geometry": { "type": "Polygon", "coordinates": [-62.5359497334, -9.7318235272] }},         { "type": "Feature", "properties": {"id": "1100031", "name": "Foz do Iguaçu", "description": "Cabixi"}, "geometry": { "type": "Polygon", "coordinates": [-60.3993982597, -13.4558418276] }} }


Can I purchase a gift certificate online for steam that is NOT associated with a specific game?

Sorry if this is a repeat question - I didn't see it on the steam FAQ or other questions on here.   I'd like to purchase a gift certificate for someone on steam and let them choose which game they want.  Is this possible?  Or can I only purchase/gift specific game titles?


Shortening URLs in the SMS being sent from Service Cloud

We are sending SMS messages from Service cloud using Transactional API(Marketing Cloud).We were planning to send attachments but transactional API does not support attachments hence we have decided to include attachment links in the SMSes. But the links for those attachments are quite big.How can we personalize/shorten the url. My plan is to send a small url in the SMS and when the user clicks,he must be redirected to the original attachment url. How can this be implemented and Is it even feasible?Please share your expertise and options you see to implement this use case. Just to inform all the templates are already configured in Service Cloud and we cannot redo the wheel to configuring the templates in marketing cloud with AMPScript.


What does -1 signify in system.schema_version?

The Drupal 7 {system} table has a schema_version column. Its default value is -1 as indicated by the DESCRIBE system; MySQL command.  Sometimes an update function won't run if the module's schema_version is -1.  For instance, I have site that migrated from Drupal 6 to Drupal 7 quite some time ago.  Recently I found that a database column that should have been introduced by honeypot_update_7100() never ran.  I'm not sure whether or not the version of honeypot at the time of the migration contained that function.  After changing the schema_version to 0, update.php ran that update and the missing column was introduced.  See  for similar stories.  Is -1 treated specially?  Do all -1's potentially need to change to 0 for their update functions to run?


How do I set tab ordering in WPF? I have an ItemsControl with some items expanded and some collapsed and would like to skip the collapsed ones when I'm tabbing.  Any ideas?


Undefined reference error in initializing a static pointer array of a class in C++

This completely sums up the problem I am having right now:  class A{ public:     int Avar;     A(int Avar = 0){this->Avar = Avar;} };  class B{ private:     static A *AArray; public:     static void setAArray(); };  int main(){     return 0; }  void B::setAArray(){     A *data;     data = new A[10];     AArray = data; // <- delete this line and the program complies }   This piece of code says I have an undefined reference to 'B::AArray' and won't compile. How do I resolve this if I want a static pointer to an array of class A objects in class B?  Note: my class does not use multiple files currently and everything is under one .cc file  Edit: the question that is marked as duplicate as does not deal with a pointer or with an array of objects from another class. Tried solution from said post with no results.


Is there a problem to use 2 passports, one for getting into country and another whilst coming back?

I am dual national of country X and Y. When I will be traveling from country X to Y, I want to use country Y's passport. When I will be coming back to country X from Y, I want to use country X's passport. Would there be any issues what so ever not just on airports but in future ?


User network profile doesn't show no. questions/answers for area51

The  doesn't show any questions or answers at area51:  However, my  does show that I have 3 questions and 1 answer:  Why aren't those shown in the network profile page?


Showing that every field is an integral domain.

The proof I have starts of with $\;xy=0\;$ in a field.   Then $x^{-1}$ exists because it is a field.  Then $x^{-1} xy=x^{-1} 0$.  Therefore $y=0$.  But surely if an integral domain can not have any zero divisors, how can we end the proof by saying $y=0$? Surely then y is a zero divisor and hence the field is not an integral domain?


I buy a stock at 10$ and sell it for 100$ where does the money come from

This is probably a typical beginner question.  Imagine I buy today a stock for 10$. The market gods are good to me and one day later it has a value of 100$, at which point I sell it and cash out.  Are those 90$ profit I made free money? Where do they come from?


Can't see the object in rendered image after motion tracking

I was watching camera tracking tutorials in youtube (Blender 2.8 Camera tracking tutorial (part 1)) and did exactly as shown in the video, but after motion tracking in the composite tab I can't see the suzanne object in the rendered view , after pressing the f12 I can only see the suzanne object but not the background, even though I can see everything in the "set up tracking scene in 3d view".


Help me understand the proof that usual ordering $\leq$ is not first-order definable in the structure $\left(\mathbb{N};s\right)$.

Here is the outline of the proof, given by spaceisdarkgreen:   The models of $Th(\mathbb{N},s)$ consist of a copy of $\mathbb{N}$ and any number of copies of $\mathbb{Z}$.  For any two elements in different copies of $\mathbb{Z}$ there is an automorphism swapping them.  This means there are models of $Th(\mathbb{N},s)$ in which we cannot define an ordering (or more generally any total antisymmetric relation).  If we could define an ordering in $(\mathbb{N},s)$ the formula would define an ordering in any model of its theory.   Here is what (I think) I understand. The set $\mathbb{N}$ and the function $s$ are axiomatized by Peano axioms:   $0\in\mathbb{N}$ $\forall x\left[x\in\mathbb{N}\rightarrow s(x)\in\mathbb{N}\right]$ $\forall x\left[x\in\mathbb{N}\rightarrow\neg0=s(x)\right]$ $\forall x\forall y\left(x,y\in\mathbb{N}\rightarrow\left[x=y\leftrightarrow s(x)=s(y)\right]\right)$ $\forall K\left(0\in K\wedge\forall x\left[x\in K\rightarrow s(x)\in K\right]\rightarrow\mathbb{N}\subseteq K\right)$   Let call $\mathcal{PA}$ the set of the above statements. Then, theory $Th(\mathbb{N},s)$ is the set of all the sentences $\phi$ such that $\phi$ is a consequence of $\mathcal{PA}$:   $Th(\mathbb{N},s)=\{\phi|\mathcal{PA}\vdash\phi\}$  Models of $Th(\mathbb{N},s)$, are the structures that satisfy it's sentences. A structure has a domain $D$. The domain of a model of $Th(\mathbb{N},s)$ must contain $\mathbb{N}$, otherwise it cannot satisfy the sentences of $Th(\mathbb{N},s)$. But $D$ could contain other things also. Since $s$ must be a total function, for $x_{i}\notin\mathbb{N}$ we may also have:  • Other infinite sequences of objects with an initial element $x_{0}$: $s(x_{0})=x_{1},s(x_{1})=x_{2},...$  • Infinite sequences without an initial element: $...s(x_{i})=x_{i+1},s(x_{i+1})=x_{i+2},...$  • Circles: $s(x_{0})=x_{1},s(x_{1})=x_{2},...s(x_{n})=x_{0}$  • Finite sequences like $s(x_{0})=x_{1},s(x_{1})=x_{2},...s(x_{n})=x_{n}$   e.t.c.  Now, I'm not sure about the meaning of the expression “structure $\mathbb{N}+\mathbb{Z}+\mathbb{Z}$”, mentioned by Noah Schweber , and either for spaceisdarkgreen's statement, “The models of $Th(\mathbb{N},s)$ consist of a copy of $\mathbb{N}$ and any number of copies of $\mathbb{Z}$”, in the comments. Surelly here “$+$” does not mean union, otherwise $\mathbb{N}+\mathbb{Z}+\mathbb{Z}=\mathbb{Z}$. And surelly $D$ can not have more than one copy of each of it's elements. So, I guess, what is meant is that, along with $\mathbb{N}$, we may also have two or more infinite sequences of the form $...s(x_{i})=x_{i+1},s(x_{i+1})=x_{i+2},...$ (which is of the same form as the sequence of integers).   If the above is correct, then, obviously, Peano axioms cannot define an ordering relation that holds for objects that are not in $\mathbb{N}$, because if we rearrange them, the sentences of $Th(\mathbb{N},s)$ will still hold. PA do not say anything about these objects anyway. But, let “$\leq$” holds only for elements of $\mathbb{N}$. What is the problem with that? And why then “the formula would define an ordering in any model of its theory”?   Or, equivalently, suppose we have the following version of first-order Peano axioms:   $\forall x\left[\neg0=s(x)\right]$ $\forall x\forall y\left[x=y\leftrightarrow s(x)=s(y)\right]$ $\forall\overline{y}\left[F(0,\overline{y})\wedge\forall x\left[F(x,\overline{y})\rightarrow F\left(s(x),\overline{y}\right)\right]\rightarrow\forall zF(z,\overline{y})\right]$, where $F$ is any formula of $k+1$ variables and $\overline{y}=y_{1},y_{2},...,y_{k}$.   From them it follows that everything is in $\mathbb{N}$ (thus, $\left|D\right|=\aleph_{0}$). Then, I can not see how we get to the conclusion.


two different lists of figure in the same document

I'm writing my Phd thesis with parts chapters and sections. It is divided in two very different subjects of research and I'd like to have a clear separation in the document and in the Table of Contents. In particular I'd like to have two different List of Figure and two List of Tables at the end of each parts of the document and not all together at the end of the document. I think that I have to create some new environment but I'm not able to get my result.  To construct two different new figure environments I simply inserted:   \newenvironment{myfigure1}{\begin{figure}}{\end{figure}}    in all chapters of the first Part of the document and  \newenvironment{myfigure2}{\begin{figure}}{\end{figure}}   in all chapters of the second Part  Also I modified the main file as follows:     \newlistof{myfigure1}{List of Figure}   after the chapters of the first Part  and    \newlistof{myfigure2}{List of Figure}    after the chapters of the second Part in the main file.     Sorry for my naivety


Will Canada accept my passport near expiration date?

I am going to Canada from Minnesota, USA 7/11/20 and returning 7/18/20 to MN. My passport expires 8/16/20. Will Canada accept this passport?


Generalizing the Chinese remainder theorem with fibred products

For a commutative ring $R$ and ideals $I,J\subset R$ with $I+J$ we have an isomorphism $$R/(I\cap J)\cong R/I\times R/J.$$ But I'm wondering how much can be said if $I+J\neq R$. We still have an injection $$R/(I\cap J)\ \hookrightarrow\ R/I\times R/J,$$ but this is not surjective in general. In fact we even have an injection into the fibred product $$R/(I\cap J)\ \hookrightarrow\ R/I\times_{R/(I+J)}R/J,$$ which is the usual Cartesian product if $I+J=R$. My question is whether this latter map is surjective in general? For the few simple examples I checked it is indeed surjective. However, my failed attempts at proving this seem to suggest that it isn't surjective, but I haven't been able to find a counterexample.


How to make a point out of 2 intersecting lines?

I have 2 lines, and I want to get the point where they intersect. I am looking to have a point created on the point of intersection. How can this be done?


How is a Targaryen immune to molten metal?

In the scene in  S01E06 where Khal Drogo pours molten gold over Viserys's head and he dies, Daenerys says that a real (dragon) Targaryen could never have been killed by that.  While we know that dragon blooded Targaryens are immune to fire, how does that translate to being immune to a pot full of molten gold? The Molten metal might have anyways killed any person on whom it was poured over.


After Signout How to Sign In with Different Gmail Account

Sign In with Google Works good and SignOut Also but when i sign In again it signs in me with the same account which I use Previously to signed In but i want every time i signed out it should ask me all time to choose account with which You want to sign in but my app crashes as i use below code to perform that functionality   private void SignOut() {         // Firebase sign out         auth.signOut();          // Google sign out         mGoogleSignInClient.signOut().addOnCompleteListener(this,                 new OnCompleteListener<Void>() {                     @Override                     public void onComplete(@NonNull Task<Void> task) {                         //updateUI(null);                         Intent intent=new Intent(Welcome.this,MainActivity.class);                         startActivity(intent);                     }                 });  }   LogCat   java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.tasks.Task com.google.android.gms.auth.api.signin.GoogleSignInClient.signOut()' on a null object reference                                                                                at com.clone.tracking.tourism.tourismapp.Welcome.SignOut(Welcome.java:123)                                                                                at com.clone.tracking.tourism.tourismapp.Welcome.onNavigationItemSelected(Welcome.java:104)   Line 123  mGoogleSignInClient.signOut().addOnCompleteListener(this,  LINE 104  this is where i call  SignOut(); method


How can I fix this Windows 2012 Dashboard Error : Google Update Service

I just installed a fresh new Windows 2012 x64 Virtual Machine.  The very first thing I did was install Google Chrome.  When I went to the Dashboard, I get the following error (or it's made to look like an error).    So,   Anyone know what this error is all about? How can i 'fix' this?   Thank you kindly.  EDIT: Please don't suggest I uninstall G-Chrome as a fix.


Nielsen and Chuang: Demonstration of equation 2.12

Reproduced from Nielsen & Chuang's Quantum Computation and Quantum Information (10th Anniversary Edition) in page 64:  We've seen that matrices can be regarded as linear operators. [...] Suppose $A: V \rightarrow W$ is a linear operator between vector spaces $V$ and $W$. Suppose $|v_{1}\rangle,...,|v_{m}\rangle$ is a basis for $V$ and $|w_{1}\rangle,...,|w_{m}\rangle$ is a basis for $W$. Then for each j in the range 1,...,m, there exist complex numbers $A_{1j}$ through  $A_{nj}$ such that $$A|v_{j}\rangle = \sum_{i} A_{ij} |w_{i}\rangle \tag{2.12} $$  Looking for information about this equation, I was not able to find any demonstration. I saw in other websites and books that they use this equation, but not where it comes from. I'm presenting this question because I made a mistake with equation (2.12) in . But I'm still not understanding why, once I've got members of the matrix of the operator, I can't use it directly with vector components. And I believe the problem comes from equation (2.12). Thanks for all information or advice you can give to me.


Is Java serialization comparable with encryption?

I just want to clear the concept about Java serialization process. It clearly states that it helps to convert the object's state in the sequence of byte, that means it helps to save the object's information into byte formed.  My question is, is Java's Serialization and Deserialization process comparable with network's encryption and decryption process? Here is my simple code:  package com.java;  import java.io.Serializable;  public class employee implements Serializable {    public String firstName;    public String lastName;  }   Here  class employee  implements the Serializable interface.and it has two variable firstName and lastName. It is very OK:  package com.java;  import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectOutputStream;  public class SerializaitonClass {  public static void main(String[] args) { employee emp = new employee(); emp.firstName = "Gary"; emp.lastName = "Michel";  try { FileOutputStream fileOut = new FileOutputStream("./employee.txt"); ObjectOutputStream out = new ObjectOutputStream(fileOut); out.writeObject(emp); out.close(); fileOut.close(); System.out.printf("Serialized data is saved in ./employee.txt file"); }  catch (IOException i) { i.printStackTrace(); } } }   In the class  SerializaitonClass,create the employee object and access the instance variable(firstname,lastname) and initilize the value.  When I run this,it creates employee.txt file.  When open this file, I get like that  ¬í sr com.java.employeeÜ@<~â™` L    firstNamet Ljava/lang/String;L lastNameq ~ xpt Garyt Michel   so it converts the whole object's information into byte format. When I use deserialization then I get desired output.  So, can I compare this process with encryption process in network? Maybe I'm totally wrong, so please help me understand.


How do I install MATE (the desktop environment)?

I have seen several youtube videos that are showing MATE (The Gnome 2.x fork) installed in 11.10. How can I install it to test it out in 11.10 and above.  If it helps the only sources I know of are:  , , and


How to find the order of a group generated by two elements?

What is the order of a group $G $ generated by two elements $x$ and $y$ subject only to the relations $x^3 = y^2 = (xy)^2 = 1$? List the subgroups of $G$.  Since the above relation is the 'only' relation, I presume that the order of $x$ is $3$ and the order of $y$ is $ 2$. Also y is the inverse of itself, and xy is the inverse of itself. The inverse of $x$ is $x^2$.  I have calculated the elements of the group manually using the given relation.  $$G = \{1, x, x^2,y, xy, x^2y \}$$  I want to know if there is a formula to calculate the order of $G$? I came across another question where the above relation is $x^3 = y^2 = (xy)^3 = 1$. In this case the group $G has order 12. It is very time consuming to calculate the elements manually. Is there a better way?


Find coordinate of point on the boundary of a circle given a latitude/longitude and radius

I understand how to use the  to compute the distance between two points on the earth. However, I would like to answer a similar, albeit different question. How can I compute the latitude/longitude of any point on the boundary of a circle?  For instance, I have a center point at 31.782643, -102.291938 and a radius of 245km. I would like to find the latitude/longitude coordinate for any point on the edge of this circle. How can I do this?


Why doesn't Stack Overflow use a best answer chosen by votes?

I often see many questions where users poor their hearts out creating high-quality answers that are merely upvoted, but never selected as the answer. The user who asks the question picks the answer that may not be the correct or best one. They may also pick an answer based on criteria they never specified.  Why doesn't Stack Overflow use a best answer system based on votes?


uk standard visit visa refused, can a us citizen still enter the country?

I am a US citizen who applied for a 6 month standard visitor visa. Due to some clerical errors on my application, I was refused the visa. I do not have time or they money before my scheduled travel plans (I leave for Germany in less than 3 weeks, will be travelling in the Schengen zone, and then plan to enter the UK about a month and a half later after my first travels), to apply for another visa. I was wondering if my visa refusal will effect my entrance into the UK. I do know that US citizens are granted 6 months leave-to-enter at border control.


Unable to load/mount Window 8 hard disk partition

After installing Ubuntu 14.04 along with window 8 I am unable to load Windows and unable to mount hard disk partition.  The message shown is given below :  Error mounting /dev/sda6 at /media/jeetu/24386BED386BBD04: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,dmask=0077,fmask=0177" "/dev/sda6" "/media/jeetu/24386BED386BBD04"' exited with non-zero exit status 14: The disk contains an unclean file system (0, 0). Metadata kept in Windows cache, refused to mount. Failed to mount '/dev/sda6': Operation not permitted The NTFS partition is in an unsafe state. Please resume and shutdown Windows fully (no hibernation or fast restarting), or mount the volume read-only with the 'ro' mount option.


Wrong text instead of reference numbers with the spbasic bibiography style

I am writing a paper to a Springer journal and I am trying to use   \bibliographystyle{spbasic} However, instead of the number of the reference in the list of references I get something as:     [Hundsdorfer et al(1995)Hundsdorfer, Koren, van Loon, and Verwer]   followed by the citation  What should I do to get the number in the square brackets?  \documentclass[smallextended]{svjour3} \begin{document} \cite{Hundsdorfer:adv}  \bibliographystyle{spbasic}  \bibliography{moje.bib}   % name your BibTeX data base  \end{document}   I may have to do the bibliography manually, as no Springer provided bibtex style produces the output that can be seen in the journal articles.


Are Riemannian Geometry and Differential topology the same thing?

I'm not an expert on the subject, but I was wondering what's the difference between "Riemannian Geometry" and "Differential topology". To me the names suggest they're different things, but looking through some of the books preview they seem to have similar content.  Can anyone clarify? Is maybe one a subset of the other? What sorts of problems do they allow to solve that the other doesn't etc.


Is there an approximation to the natural log function at large values?

At small values close to $x=1$, you can use taylor expansion for $\ln x$:  $$ \ln x = (x-1) - \frac{1}{2}(x-1)^2 + ....$$  Is there any valid expansion or approximation for large values (or at infinity)?


Turning water pump on/off using Arduino Uno R3

I'm trying to build a simple system to turn a water pump every 24 hours for 10-20 seconds. I have 5V pump. When I connect it to 5V, GND it works but when I connect it to pin 12 (or any other digital pin) and GND it does not work. Here's my sample sketch:  int led = 12;  void setup() {                   Serial.begin(9600);   pinMode(led, OUTPUT);      }  void loop() {   digitalWrite(led, HIGH); }   What am I doing wrong?


I would like to clarify my understanding on why mass terms in Lagrangians of gauge theories are forbidden.  It's often repeated that particle masses are forbidden by electroweak symmetry because it is a chiral theory. I want to make a distinction between fermionic masses and gauge boson masses.   Looking through the transformations of gauge boson mass terms, it seems that these are in fact always forbidden by their respective gauge symmetry. Is this correct? (So if there was no SU(2) symmetry, the photon and gluon would still need to be massless?)  In which case, the electroweak symmetry is actually responsible for forbidding all other mass terms (i.e. weak boson masses and fermion masses) due to the usual chiral arguments. Is this correct?


Need help solving Recursive series defined by $x_1 = \sin x_0$ and $x_{n+1} = \sin x_n$

$x_1 = \sin x_0 > 0$  $x_{n+1} = \sin x_n$   Prove   $\lim_{x \to \infty }$ $\sqrt{\frac{n}{3}} $ $x_n = 1$    having problem of trying to figure out what value for the $x_0$ starts at.


How does reporting AMT for shares later sold as long-term cap gain work?

I'm unsurprisingly confused:  If I exercise ISOs in Jan 2017 and sell them in Feb 2018, how is income reported for AMT purposes and profit reported for cap gain purposes -- are BOTH reported on my 2017 return, even if the shares were sold in 2018 (but before April 15)?  Or, must I report for AMT purposes in 2017, and on my 2018 return, will I report some kind of adjustment due to the fact that the shares were sold at a different FMV than when they were exercised?


How to turn the ".get" in Python requests.get into a variable?

I'm new to programming with Python. I'd like to set a variable for the Python requests method (.get, .post, etc.). Something like: import requests  method = 'get' url = 'https://google.com'  response = requests.method(url)  This of course results in an error because requests does not have a .method option. It feels like the answer lies with getattr, but I don't understand what parameters to pass getattr. Any advice? Thank you


Java: How to read files on directory based on Date

Task is to get files(pdf) from a local directory, by date. In my scenario we have bulk of pdf files in a directory with different date modified(past few years).  I'm trying to write a loop(which iterate for each day for a year) where i would like get files for each date. can someone help with How to read files on directory based on Date using Java.  Any help is appreciated.


Should questions be tagged with both a tag and a "sub-tag"?

In my retagging madness today, I came across a few questions tagged similar to the following:  [visual-studio], [visual-studio-2005]  My question is: should questions be tagged like this with both tags, or is it better to only apply the more descriptive/precise tag? How would this affect searching?    Another issue. With a tag such as [visual-studio], there's 2 additional levels of tags: [visual-studio-2005] and [visual-studio-2005-expres] (trailing 's' is not a typo -- tag length limit is in play), so if I have to tag a question with VS2005 Express and I should tag with all 3, I've burned up 3 of the 5 allowed tags just for the environment I'm using, which doesn't seem right. In fairness, these instances are probably rare, but certainly 2 out 5 tags can be significant sometimes, too.


Bash in php exec in webpage don't colors for png and mp3 files on Linux

I have code like this in php:  header("Content-Type: text/plain"); exec("/bin/bash -c 'ls --color=always'", $result); echo implode("\n", $result);   and I've got result (escape is not visible)  Makefile README Yann Tiersen - Comptine d'un autre ete L'apres midi.mp3 bush-src.js bush.js bush.min.js [0m[01;34mcgi-bin[0m config.json [01;34mcss[0m favicon.ico foo.png index.php [01;34mlib[0m ls.txt test.php test.php~ [01;32mtest.txt[0m   It show ANSI escape codes for directories and executable files, but when I call from command line  php -r "exec('bash -c \"ls --color=always\"', \$result);echo implode(\"\\n\", \$result);" | less   I've got this:  bush.js bush.min.js bush-src.js ESC[0mESC[01;34mcgi-binESC[0m config.json ESC[01;34mcssESC[0m favicon.ico ESC[01;35mfoo.pngESC[0m index.php ESC[01;34mlibESC[0m ls.txt Makefile README test.php test.php~ ESC[01;32mtest.txtESC[0m ESC[00;36mYann Tiersen - Comptine d'un autre ete L'apres midi.mp3ESC[0m   png and mp3 have ANSI escapes codes, why php exec from webpage don't give that as return?


So I was working and there was a directory that I was periodically changing to my user in  a root terminal so that I could open the files in text editors, but I accidentally pressed / instead of . and this was the command I put out:  chown -R emil.emil /   Then immediately panicked ^C and put in another command, as I thought I could always change back the files I needed to access:  chown -R root.root /   So now I can't do su from emil to even try to fix this, as I'm getting permission denied error. I'm on Ubuntu could someone tell me if there is a way I could fix this, without absolutely reinstalling the whole thing.  TIP  If you are trying to get root access, and are getting this permission denied error when using su try this command:  gksu gnome-terminal   It will prompt you for the root password and open a new root terminal for some reason this works and gives me root access, when su doesn't.


If $P(A \cup B \cup C) = 1$, $P(B) = 2P(A) $, $P(C) = 3P(A) $, $P(A \cap B) = P(A \cap C) = P(B \cap C) $, then $P(A) \le \frac14$

We have ($P$ is probability): $P(A \cup B \cup C) = 1$ ; $P(B) = 2P(A) $ ; $P(C) = 3P(A) $ and $P(A \cap B) = P(A \cap C) = P(B \cap C) $. Prove that $P(A) \le \frac{1}{4} $. Well, I tried with the fact that $ 1 = P(A \cup B \cup C) = 6P(A) - 3P(A \cap B) + P(A \cap B \cap C) $ but I got stuck... Could anyone help me, please?


Neutron star aliens come to visit Earth. As they leave, they give us three gifts including removing black holes from the Sun

Hard SciFi book, with nearly 2 dimensional life (on a neutron star) that goes zipping past earth. They see our sun and that sparks their interest in space (they evolve super-fast).  We send a spaceship, and eventually they communicate with us, reading our entire list of knowledge in just one or two of their generations. One of their tiny space-ships detects (and removes) cancer from a female human astronaut.  As their world leaves our system they give us 3 gifts - the first of which is removing tiny black holes from the core of our sun.


I am trying to make a floor plan for my office, have managed to make all of the rectangular components (e.g. the rooms) however some of the desk layouts are circular and I haven't been able to work out how to make exact and measured circles. They need to have a radius of 1.45m.


Android Studio how to have a permanent variable

I want to create a class that has a variable, that this variable can be modified and obtained from other activities and this varable always be saved.  I've tried to do this class with the variable "TipoAnuncio":  public class Filter_Object  {     private String TipoAnuncio ="Perdidos";      public String getTipoAnuncio(){         return TipoAnuncio;     }     public void setTipoAnuncio(String TipoAnuncio){         this.TipoAnuncio = TipoAnuncio;     } }   And i've tried to get and to set this variable from other Activities, for example:  public class FilterActivity extends AppCompatActivity {      private Filter_Object filter; protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_filter);           Log.i("anuncioahora", filter.getTipoAnuncio()); } }   An error appears which says :java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.julianrc1.petracecitm/com.example.julianrc1.petracecitm.fragments.Intents.FilterActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.example.julianrc1.petracecitm.Objects.Filter_Object.getTipoAnuncio()' on a null object reference  Thanks for your help :)


How to fix issues after rotating a table with sidewaystable directly below the Chapter title?

I am trying to get a big table in the Appendix, directly below the chapter title.   Sidewaystable from the rotating package works, since it nicely rotates the entire table, including caption and footnotes.   After searching a while, I found that the floatrow package adds the [H] option to the sidewaystable-environment, such that it can be forced to be placed at a specific location.   However, when adding that option to the table below the chapter title, not the table is sitting below the title but the title slides down and sits above the table. In result, an additional blank page is left before the title.  Moreover, the title is below a header, which I was unable to remove through \thispagestyle{empty}. I have added a minimal working example below.   Is there a way to move the table up instead of the title down, in order to fix (i) the empty page and (ii) the header occurrence?  \documentclass[openright]{scrbook} \usepackage{booktabs} \usepackage{rotating} \usepackage{floatrow}  \begin{document} \chapter{Appendix} \begin{sidewaystable}[H] \caption{Experimental settings.} \begin{tabular}{lccc} \toprule  Test & Yes & No & Yes \tabularnewline \midrule 1  & 2 & 3 & 4\footnote{This is absolutely necessary information with reference to 4.}                    \tabularnewline \bottomrule \end{tabular} \label{table_exp_settings} \end{sidewaystable} \thispagestyle{empty} \end{document}


I know the difference between pass by value and pass by reference. But while coding a logic I found it to be not completely clear. Below is the code that I tested with a reference type arr, primitive int i and an object root of type Node(user defined). static void recursiveFn(int[] arr, Node root, int i, int times) {     if(times > 3)         return;      if(times == 2) {         arr[0] = 1;         i = 1;         root = root.next;     }      times++;      recursiveFn(arr, root, i, times);     System.out.println(times+" - "+arr[0]+" "+i+" "+ root.data); }  The output was: 4 - 1 1 1 3 - 1 1 1 2 - 1 0 0 1 - 1 0 0  The index zero of the array persists in the call stack while the control go backs to the previous recursive call - This is what pass by reference mean. The int i produced its current value at respective function call. I didn't understand why the root being an object didn't persists its value through out the recursive call.


Why does $k/m=\omega^2$ for harmonic motion?

Can anyone please give me a proof for $k/m=w^2$ in simple harmonic motion?  I have tried energy conservation and Newton's laws as follows :  In the case of a mass-spring system,  $$F=ma =-kx\\ F=ma = mr\omega^2 $$  hence   $$\frac km  = \omega^2$$  Or   $$\frac12 mv^2 = \frac12kx^2$$  $$\frac km  =  \frac{V^2}{x^2}   =   \omega^2$$  therefore $k/m  =  \omega^2$  Are these valid and correct? I have been stuck in this for the  entire day.


To clarify at first, I have very little knowledge in biology and paleontology so there might be very obvious things I overlook.  According to the evolution theory, there must be a graduate evolution process over millions of years such that the skull and the horns of the Triceratops gradually appear over time. However why there is no fossil record of such "intermediate" form between Triceratops and earlier dinosaurs? I mean there must be some intermediate dinosaurs that has a short skull that almost looks like a small mountain on the neck and very short horns. However based on my internet search I can't find any information that confirms existence of such intermediate dinosaurs.   I just want to know is there any such evidence of graduate evolution among paleontologists or the evolution of dinosaurs is still much based on speculation (without firm evidence)?


How to force Windows 7 to ask for a "fresh" IP address from DHCP server?

I'm troubleshooting a certain issue with my DHCP configuration, and need my Windows machine to ask for a "fresh" IP address, so I can see which address DHCP server gives by default.   When I do ipconfig /release followed by ipconfig /renew, Windows "proposes" its old IP address to the DHCP server (just checked with Wireshark, initial "DHCP Discover" message has Option-50 (requested IP address) with Windows machine's old IP).  Tried disabling/enabling network adapter. Same behavior.  Question: How can I force Windows to just ask for a new IP address, without proposing its old IP address.


In set theory one often uses $\notin$ as with a slash through $\in$. How can I produce a similar slash through $\eta$?


What is Automorphism group of $Z \oplus Z$? Please give some hints. I feel it is some matrix group looking as the group as a Z module.


So my Pokemon eggs are reaching "maturity" then they just disappear. I don't get a new Pokemon. The egg just disappears. I had this happen with a 2k and a 5k now. Is this happening to anyone else?


How to list RPM packages installed in order of installation date

I'd like to see a list of software installed in the order of the date they were installed. The order doesn't matter (newest to oldest & vice-versa) as long as they're arranged by date.  I'm mainly interested in seeing what libraries I've installed. Since I've installed so many, I need to know what libraries were installed together so that I may recall what software required these, if I need to do a fresh installation.  I'm using Fedora 16 w/ the yum.


I have created an object but when called ,it says not defined (JavaScript)

I watched a tutorial and did the same exact thing. now, this "not defined" error keeps showing I even tried in another browser but the same result. I'm new to JS need help thank you.    <html> <head> <script type="text/javascript">   function person(name, age){   this.name = name;   this.age = age;  }       var milz = new person("milz", 23);   var stefi = new person("stefi", 19);  </script> </head>     <body> <script type="text/javascript"> document.write("hello "); document.write(stefi.age);   </script> </body> </html>


Confidence interval around difference of regression coefficients

I am interested in comparing standardized regression coefficients within the same model. A linear hypothesis test (e.g., car::linearHypothesis in R) can tell me whether the difference between them is significant, and I can calculate the difference to get a point estimate. However, I am not sure how to get a CI around that. Currently, I believe that I can use $\beta_\delta$ + 1.96 * $\sqrt{SE1^2+SE2^2}$ in the same way that I would deal with the difference between two means, but I am not sure if that is applicable in this case?


Confusion with Augmented Dickey Fuller test

I am working on the data set electricity available in R package TSA. My aim is to find out if an arima model will be appropriate for this data and eventually fit it. So I proceeded as follows:  1st: Plot the time series which resulted if the following graph:    2nd: I wanted to take log of electricity to stabilize variance and afterward differenced the series as appropriate, but just before doing so, I tested for stationarity on the original data set using the adf (Augmented Dickey Fuller) test and surprisingly, it resulted as follows:   Code and Results: adf.test(electricity)               Augmented Dickey-Fuller Test data:  electricity  Dickey-Fuller = -9.6336, Lag order = 7, p-value = 0.01  alternative hypothesis: stationary Warning message: In adf.test(electricity) : p-value smaller than printed p-value  Well, as per my beginner's notion of time series, I suppose it means that the data is stationary (small p-value, reject null hypothesis of non-stationarity). But looking at the ts plot, I find no way that this can be stationary. Does anyone has a valid explanation for this?


Why is "Gravity as a result of space-time curvature" not accepted as a fact?

Now that gravitational waves are confirmed. Not to mention the other numerous experimental verifications. Why do we still need an elusive graviton? Isn't there not enough evidence that the space-time curvature is a thing? Please don't mind if the question is stupid, I'm not a physicist, it's a hobby of a sort.


Can anyone do this with the latest OS and XQuartz? On my machine, XQuartz opens but displays nothing. E.g., after loading a file with  drawdot (35,70); showit; drawdot (65,70); showit; draw (20,40) .. (50,25) .. (80,40); showit;   I see a blank XQuartz screen.


I am trying to understand slicing. How does this slice work?  >>> a=['c','b'] >>> a ['c', 'b'] >>> a[-3:-1:3] ['c']   I have already read all the posts and cannot find an answer. As I understand it slice is supposed to be [start:stop:step]. But if I start at -3 after one step I am at 0. How exactly does this work? Which indexes are printed? The ones in the range?


How to check encryption status (completeness) of an external disk?

When I click on an external USB disk in Finder's Sidebar it shows it is still encrypting (which is expected):    diskutil shows only Encrypted: Yes in CLI and GUI.  Is there any way to check the current status of encryption (percentage complete)?


Can I use my iPhone's 18W adapter on my MacBook Pro? And vice versa?

Are the new 18W power adapters for the iPhone 11's compatible with the MacBook Pro 13-inch (2019)?  Is it safe? Anything to watch out for?    What about using my MacBook's adapter (with the correct cable) on my iPhone 11 Pro? Is that safe


How to catch syntax errors in included files in PHP?

I'm developing a plugin system, which of course needs to include the plugin files. So far everything works very well - exceptions get catched etc.  But my very last wish would be to even be safe from corrupt plugin files containing syntax errors. Is there a way to catch Fatal Errors in included files?


Why is it not possible to simplify $b=(X'X)^{-1}X'y$

Why is the following not possible: $$ b=(X'X)^{-1}X'y = X^{-1}(X')^{-1}X'y=X^{-1}y $$ While this term $(AB)^{-1}=B^{-1}A^{-1}$ applies to any two matrices as long as both are of full rank and are $nxn$, the problematic part is when X is not $nxn$. $X'X$ always is a nxn matrix, and hence may have an inverse. Non squared matrices need not have an inverse. Any other reason to add?


using Python3.5 i have two lists of strings, and i want to 'multiply' the two lists so i can do an ebay search for carparts, and print to the console.   cars = ['ford focus', 'honda civic', 'chevy truck',] parts = ['ignition', 'head light']  for car in cars:     for part in parts:         print(cars[car]) + parts[part])   expected output:  >>>ford focus ignition ford focus head light honda civic ignition honda civic head light chevy truck ignition chevy truck head light   Ive tried several different methods, but cant seem to get anything to give me the output i need. i attempted to use numpy, but couldnt figure out how to get it to install. "pip install numpy" at cmd kept giving me some sort of error that i couldnt figure out. i need the output to be both strings on the same line, because i will copy and paste them into a notepad document and utilize the data by the line for an ebay search.


Living in India with a Kenyan passport and OCI card, just got my Portuguese passport. Immigration to the UK without problems

Kenyan passport holder living in India with an OCI card for the last 20 years, just got my Portuguese passport and living for the UK soon and wanted some information about the immigration part, whilst leaving India, I need to show my Kenyan passport and OCI card and when I reach the UK do I show my Portuguese passport only? Once in the UK I plan to apply for dual nationality, Kenyan and Portuguese, will this create any problems for me?