I am trying to remember a novel from when I was younger. Oh about late 1980s to early 1990s. The book could be older than that. It just seems my Google-fu cannot break the author or title barriers.  The book I remember reading was actually an omnibus. I believe it came out about the same time as The World of Tiers and The Book of Swords. Of the stories in the omnibus, I remember three story parts.   The first story described a world where people hibernated during the winter that would last until the sun came again and lone girls would stay awake. The world itself, other than the hibernation, seemed more fantasy than sci-fi. These girls would take dangerous quests to see if they they had "sun powers". In all of this was a young boy who appeared at the castle and quickly learned things. He was a good person but he was actually a plant for a planet raiding pirate band. In the end the native girl and the pirate plant defeated the pirates leaving behind other clones of the boy who was also a clone of a traveller that was captured by the pirates years ago.  The second story in the omnibus described a daughter of these clones going out from the valley to find her father who had started living with the desert people. She too developed "sun powers" and the father had with him multicolored silks that their colors reflected equal emotions back at the wearer; red equals anger, etc. the silks also seemed to contain memories.  The third story in the omnibus describes the journey of the daughter from the first story going out on a quest to find the origins of these silks. In this she does and discovers creatures that weave silk, emotions, and memory all into each piece of silk. During this journey, she too develops "sun powers".  Could someone identify this book?

I read this set of stories in the 80's.  What I recall is this:  A planet where the ruling caste was made up of humanoid women.  These women would, as almost pubescent girls, go out into the wilderness with only a spear and attempt to kill an animal in a life or death struggle.  When it happened, they would burst open a DNA packet in themselves that caused them to rapidly mature, their skin to become bronze colored, and give them some kinds of other "powers", I think over fire.  They were called "Bahronas", I think.  The population of this planet was primitive, but they were in contact with an advanced humanoid species, I think of actual homo-sapiens, who were there observing and advising them.  The advanced species wasn't allowed to intervene, just advise and watch.  The main character was a castaway boy, crash landed on their planet and stranded.  He became friendly with the ruling family of Bahronas and entered their confidence.  We find out through the course of the story that he's been genetically engineered and is not a normal boy.  At some point, the advanced species notices him and explains that he is a clone of a famous explorer and a spy, and they explain that they won't do anything in front of him.  The central part of the story is something of a blur, but, the final part of the story is told in a dramatically different style and shifts to a planet populated by catlike creatures who live in boughs of silk scarves, some of which sing.  THey are recording devices which play back the songs.  On this planet, there is another silk scarf, a white one, which doesn't play a song at all.  The cat creatures are greatly disturbed by it when they hear it's message, which they don't understand.  The narrator then goes on to say that it's a spoken word recording, made by the explorer which the boy was a clone of, explaining that he is captured and held hostage on the planet which makes the scarves, and forced to help make them (I think.)


Definition: For a ring with unit $R$, Jacobson Radical is defined as the ideal $J(R) = \{r \in R: rM = 0 \}$ where $M$ is simple.  How do I show the $J(R)$ is nilpotent for an Artinian ring $R$? , but it uses Nakayama, which assumes commutativity. The only lead I got is forming a chain of inclusion $J^n \supset J^{n+1} \supset \dots$ and this chain terminates with $J^{n} = J^{n+k}$ for every $k \geq 1$

I have to prove the following: If $R$ is a finite-dimensional algebra over a field $F$, then $J(R)$ is nilpotent.  I thought about this, but there are some gaps:    Because $R$ is in particular a finite dimensional vector space, there is a composition series $0=R_0\subset R_1\subset\dots\subset R_k=R$ of VECTOR SPACES. Do I know that this is a composition series of $R$-modules? If yes, why? Or how can I find some?  If that is the case, I would proceed as follows: $J(R)R_n/R_{n-1}\subseteq R_n/R_{n-1}$. Now, I would like to use, that the quotient is simple, so if the above is a strict inclusion (how to show that?), then $J(R)R_n/R_{n-1}=0$. Now, by induction it is easy to see that $J(R)^k=\{0\}$.


As an example for a typical explanation about red-eye reduction pre-flashes, the description in the Metz SCA3202-M7 flash adapter manual states     Red eyes are always the result of a physical   effect. This arises whenever a person looks more   or less straight into the camera, the ambient light   is relatively dark and the flash unit is mounted on   or directly next to the camera. The flash unit illuminates the back of the eyes, revealing the blood   filled retina through the pupil. This is recorded by   the camera as a red spot in the eyes.      The red-eye reduction function brings about a significant improvement in this respect. When this   facility is used the flash unit triggers, prior to shutter operation, a few weakly visible preflashes   which are followed by the main flash. These preflashes induce the pupils to close down, thereby   diminishing the red-eye effect."   So here are three flash photographs of my eye taken with one self-timer, distance probably 8m.       There is no significant difference in iris size: if any, there is a small overall reduction throughout the (chronologically sorted) sequence with photographs taken with a distance of about 1sec.  Nevertheless the last image not even looking in the direction of the camera (with the reflexes from the flash being almost or entirely off the pupil) clearly has the strongest red-eye, followed by the first image.  The middle image, in spite of having the flash reflex basically straight in the pupil, clearly has a minimal amount of red-eye.  And PostScriptum, to counter theories that some sort of reflection law ignoring the presence of the lens is responsible or that the area conversing with the blind spot is, here another photograph where I am focusing quite closer than flash and camera are but in a completely different direction:  What gives?  The typical description of the red-eye effect strangely does not take into account that the eye is an optical system designed to create a sharp image of what you are looking at on the retina.  If there is no overlap of the image of the flash on the retina and the image of the camera's entrance pupil (the aperture as viewed through the front lens), no retina area lit by the flash will be visible from the camera's entrance pupil and consequently the sensor.  So the main objective of a pre-flash to me appears to be making the eye bringing flash and camera in focus so that their respective images on the retina are sharp and disparate.  While reducing the iris size would also help by increasing the eye's depth of focus (and thus decreasing blurring of the retina images), the effect seems minor compared to what the accommodation reflex can achieve in separation even with comparatively wide pupil.  Interestingly, in the fourth image the right eye on the left side of the image is considerably more red.  Looking closely, the eye on the right side of the image has its vertical aperture narrowed by a drooping eye lid.  This reduces the vertical blurring of the images of flash and camera on the retina, making them overlap less.  So contrary to conventional wisdom, staring focusedly at camera/flash (or a birdie waved at same distance or some other object that shares focus with camera/flash) will do most of the work even without preflash.  An urgently blinking self-timer lamp should be almost equally effective for red-eye prevention as a pre-flash.  Now the people writing about cameras and designing red-eye reduction systems know their place inside out optics.  It seems preposterous to assume that they of all people would not consider the implications of the eye being an imaging device after which cameras have been modeled complete with lens, aperture, and sensor surface.  And money is riding on it: basically every camera review tests for red-eye.  What am I overlooking?

What's the reason for red eye in photos? It only comes sometimes. Does it depend on the distance between subject and camera? Or light adjustment? I took 4 photos, some of them have red eye and some are don't. How can I avoid this? And what is a good, free tool to remove red eye?


I was searching for a solution to adding two binary strings.  My test data for proving the addition: 10 + 1 => 11 1001 + 1 => 1010 1101 + 100 => 10001 10101010 + 11001100 => 101110110  This was the code I've found by googling: public static string AddBinary(string a, string b) {     string result = "";      // Initialize digit sum      int s = 0;      // Traverse both strings starting from last characters      int i = a.Length - 1;     int j = b.Length - 1;      while (i >= 0 || j >= 0 || s == 1)     {         // Compute sum of last digits and carry          s += (i >= 0 ? a[i] - '0' : 0); // if i > 0         s += (j >= 0 ? b[j] - '0' : 0);          // If current digit sum is 1 or 3, add 1 to result          result = (char)(s % 2 + '0') + result;          // Compute carry          s /= 2;          // Move to next digits          i--;          j--;     }     return result; }  Could someone please explain to me what these three lines of code are actually doing here? s+= (i >= 0 ? a[i] - '0' : 0); s+= (j >= 0 ? b[j] - '0' : 0);  result = (char)(s % 2 + '0') + result;  I've never used a char with a plus/minus operator before and not sure what these lines are achieving. Footnote - the binary calculation looks to be correct

I have a char in c#:  char foo = '2';   Now I want to get the 2 into an int.  I find that Convert.ToInt32 returns the actual decimal value of the char and not the number 2.  The following will work:  int bar = Convert.ToInt32(new string(foo, 1));   int.parse only works on strings as well.    Is there no native function in C# to go from a char to int without making it a string?  I know this is trivial but it just seems odd that there's nothing native to directly make the conversion.


For such an extension:  public static class ImageExtensions {     public static Image LoadImage(string path)     {         using (MemoryStream ms = new MemoryStream(File.ReadAllBytes(path)))             return Image.FromStream(ms);     } }   How to make it possible to be called Image.LoadImage(path) instead of ImageExtensions.LoadImage(path)?  I can normally use other extension methods, where their first parameter is this Image img. Those work by using instance.Method().

I'm a fan of extension methods in C#, but haven't had any success adding an extension method to a static class, such as Console.  For example, if I want to add an extension to Console, called 'WriteBlueLine', so that I can go:  Console.WriteBlueLine("This text is blue");   I tried this by adding a local, public static method, with Console as a 'this' parameter... but no dice!      public static class Helpers {     public static void WriteBlueLine(this Console c, string text)     {         Console.ForegroundColor = ConsoleColor.Blue;         Console.WriteLine(text);         Console.ResetColor();     } }   This didn't add a 'WriteBlueLine' method to Console... am I doing it wrong? Or asking for the impossible?


I'm wondering if anyone knows of a tool or plugin for QGIS that allows for multi-ring buffers.  I've found a post about doing multiple buffers one by one, but was hoping there was a way to do this all in one place.  I know in ArcMap that you can set the number of buffers you want and distance, so just hoping there's something out there in QGIS to accomplish this.

I'm new to QGIS and have no programming skills.  Is there an easy/uncomplicated way to create multiple buffers around a line feature?


Recently bought a . It has Ctrl, Fn, Opt, Cmd buttons on the left. I'm trying to switch the Ctrl and Fn keys so that it's the same as the Macbook keyboard (which has Fn then Ctrl). Tried the Keyboard preferences but no luck - it doesn't seem to let me modify the Fn keys. Any idea how to map keys? (FWIW: recently switched to Mac and trying to get used to the new key layout)

I have this usb keyboard and macOS 10.14.6. :    I'm using the file  to remap several keys on a MacBook Pro. Is there a way to specify that my right Fn key has to be bound to the Option  key.  I need this since I'm trying to have an Option key on the bottom right zone of the USB keyboard, mimicking the MacBook Pro  keyboard.  I'd prefer not to use external tools.  I don't find Modifier keys settings helpful for function keys:    Using Karabiner event, it seems like keystrokes on Fn keys are not detected by the Mac. Can I fix it?


I am working on a stand alone script in python that will allow to me to specify a shapefile and being able to find a value and replace it with a new value. Does anyone know what code will allow me to do this?

I would like to find a Python script that will access an attribute table within a shapefile and either update or replace records inside a field column. More specifically, I would like to use the replace expression to convert a table record like "123-456-789" to "123456789". I have many records to process and would like the best approach to do this task using Python.


I know it is said that we do the reparameterization trick so we can do back-propagation and back-propagation cant be applied on random sampling! However, I don't precisely understand the last part. Why cant we do that?  We have a mu and a std and our z is directly sampled from them. What is the naive method that we don't do ?   I mean what were we supposed to do that didn't work and instead made us do reparameterization?  we had to sample from the distribution using mean and std, any way, and we are doing it now, whats changed?  I dont get why z in is considered a random node previously, and not now!? I'm trying to see how the first way is different than what we are doing in the reparameterization and I cant seem to find anything!

How does the  for variational autoencoders (VAE) work? Is there an intuitive and easy explanation without simplifying the underlying math? And why do we need the 'trick'?


Here is a tooltip from Eclipse, that pops open when you press CTRL+O:    Is this intentional? White text on black background does not exactly fit in, and it would be much more readable if it used some standard theme.  Can I make it so?

In a lot of applications the tooltips are just plain ugly (White text on black background, way too much contrast) or even unreadable (black or dark blue text (Hyperlinks) on black background). I want to change the background color of the tooltips to some medium gray or even some yellow or something like that, maybe even something semi-transparent.   Here is a screenshot of Eclipse which displays some source code in a tool tip with black text on black background:    Switching to a different theme (Something other than Ambiance or Radiance) helps but I like Ambiance and I want to keep it. It's just this darn tooltip color which is absolutely unacceptable.  I found several solutions for older Ubuntu versions but they no longer work with Unity in Ubuntu 11.10 because I can't find any function to customize the Ambiance or Radiance theme. So how do I do that in the current Ubuntu version?


My basil often spoils after 2- 3 days of purchasing them from the supermarket. I have tried wrapping them in a wet paper towels in order to keep them hydrated, but it doesnt seem to have any effect.  How do you preserve your fresh basil leaves for longer than a few days?

How should fresh basil be stored? The packaging suggests that the optimal temperature is around 50°F, but I can't think of anywhere in an average kitchen at that temperature. A pantry is too warm, and a fridge is too cold. So which of the two is lesser of two evils? I recently had a whole pack get moldy after one use, and it was in the pantry. I think I'm going to start storing it in the fridge now and deal with whatever quality loss I get, unless there's a better solution.


Many sites now provide a search bar without the buttons, and everyone (?) understands that you press enter afterwards anyway.  Is it beneficial to keep the Search button for this case? Do I gain or lose anything by removing it?

I can see two broad patterns as far as the design of the search field is concerned. One like we see on Google has a button that the user can hit to initiate Search. (They could also hit enter to do so)  The other pattern much like what is on this site (stackexchange) do not have a button. So the only way the user can initiate search is by hitting enter.   Has anyone done any research or analysis of this pattern ? What I have noticed is that search fields without the explicit search button (that normally is a magnifying glass) have "Search" as placeholder text, left aligned, whereas when there is no button the placeholder is usually a "Magnifying glass icon" with "Search" all left aligned.


I am looking to PDF/sites to be introduced into the concept of quaternion at high-school level math. Thanks!

I've been studying Quaternions for a week, on my own. I've learned various facts about them but I still don't understand them. My goal is to understand rotation quaternions specifically. I don't want to just memorize the formulas for using rotation quaternions, I want to truly understand them.  It's the most difficult thing I've ever tried to learn. Does anyone know any good resources for understanding quaternions?


For example I have a cube and I moved it to a certain location. I want to know if there is a way to find object's global location, so later I would be able to insert this location coordinates to another object.    So my Question is: Is there a way I can see the location of a certain object and if yes how can I insert this location coordinates to another object ?

I want an object to have the same Transforms (location, rotation, and scale) as another object. How can I copy the Transforms from one object to another?


After a system restore has occurred, is it possible to get:   a list of programs that have been permanently removed; a list of programs that will no longer function   due to the change?

My pc has starting acting weird lately. I ran scan using Nod32, malware bytes. It did detect some viruses but my PC's behaviour doesn't change. When I use Adobe reader X it doesn't find the the word given for the search and I accidently Lost my Office 2010.  I am thinking that system restore can solve these issues and reinstall Office 2010. Is it possible?


I'm trying to apply GLMs on a dataset in which dependent variable Y is dichotomous. I applied either logit and probit models, and probit fitted better than logit model. How do I justify the choice of the probit on the logit model?  #use of link=logit Call: glm(formula = DANNO ~ OCCUPAZIONE + PERCPIANTE, family = binomial(link = logit),      data = data)  Deviance Residuals:      Min       1Q   Median       3Q      Max   -2.6908  -0.1688  -0.1321   0.1012   2.3223    Coefficients:             Estimate Std. Error z value Pr(>|z|)     (Intercept)  -4.7370     0.7624  -6.214 5.18e-10 *** OCCUPAZIONE   7.3862     1.2981   5.690 1.27e-08 *** PERCPIANTE    3.0168     1.5783   1.911    0.056 .   --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1  (Dispersion parameter for binomial family taken to be 1)      Null deviance: 308.294  on 227  degrees of freedom Residual deviance:  77.096  on 225  degrees of freedom AIC: 83.096  Number of Fisher Scoring iterations: 7   #Use of link=probit Call: glm(formula = DANNO ~ OCCUPAZIONE + PERCPIANTE, family = binomial(link = probit),      data = data)  Deviance Residuals:       Min        1Q    Median        3Q       Max   -2.57471  -0.13749  -0.09375   0.08136   2.28999    Coefficients:             Estimate Std. Error z value Pr(>|z|)     (Intercept)  -2.6209     0.3606  -7.267 3.66e-13 *** OCCUPAZIONE   4.0762     0.6434   6.335 2.37e-10 *** PERCPIANTE    1.4687     0.7271   2.020   0.0434 *   --- Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1  (Dispersion parameter for binomial family taken to be 1)      Null deviance: 308.29  on 227  degrees of freedom Residual deviance:  75.95  on 225  degrees of freedom AIC: 81.95  Number of Fisher Scoring iterations: 7

What is the difference between  and ?  I'm more interested here in knowing when to use logistic regression, and when to use Probit.  If there is any literature which defines it using , that would be helpful as well.


When i try to log in to my minecraft premium account it says:     Sorry, but we couldn't connect to our servers. Please make sure that you are online, and that Minecraft is not blocked.   I tried turning off the firewall and updating Java (64-bit) but it still doesn't working. I'm using Wi-Fi. Any ideas?

What should I do when my Minecraft Launcher 1.3.11 wouldn't log me in? The console output is:                                              Sorry, but we couldn't connect to our servers. Please make sure that you are online and that Minecraft is not blocked. (CertificateNotYetValidException:NotBefore:Tue Apr 08 20:47:05 CST 2014)


Is there any integer positive number which triples in value when its last digit is removed and becomes the first digit? I’ve tried with the first 1000 numbers and Excel but could not find any. First 10,000 numbers, no single case! is there a rigorous way of tackling such a problem?

There seems to be a relationship between  and a puzzle Presh Talwalkar gave a few days ago at   I'm hoping someone can give a more rigorous explanation of the pattern I see.  $\bullet\textbf{ The Puzzle }\bullet$  He states the puzzle as: "What Positive Number Doubles When Its Last Digit Becomes Its First Digit?"  For example, the smallest solution - assuming base-10 representation - is $105263157894736842$. Which means that $$(2)\cdot105263157894736842 \quad\ \ \ $$ $$||$$ $$210526315789473684$$  Naturally, one can proceede to find solutions in other bases. The base-5 solution is $$(2)\cdot102342_5 \quad\ \ \ $$ $$||$$ $$210234_5$$  $\bullet\textbf{ Multiplicative Order Connection }\bullet$  The base-10 solutions is $18$ digits and the base-5 solution is $6$ digits. I wrote a program to generate the smallest solution in all bases and then counted the number of digits in each such solution. Here's the sequence, starting with base-2 $$2,4,3,6,10,12,4,8,18,6,11,20,...$$ $$\uparrow \quad\quad\quad\quad\ \uparrow \quad\quad$$ $$\text{Base-} 5 \quad\quad\quad \text{Base-} 10 \quad\quad$$ A quick search on  shows that these numbers are the multiplicative order of  $$2\ (\text{mod } 2B-1)$$ where $B$ is the representation base we are working in. See   This puzzle can be further generalized by finding numbers that triple instead of double upon moving the last digit to the front. Let's introduce an arbitrary multiplying factor: $k$  So the solutions mentioned above and Talwalkar's puzzle are a particular case when $k=2$  For a different example, let's look at $k=5$ in base-7. The smallest solution is $$(5) \cdot 1013042156536245_7 \quad\ \ \ $$ $$||$$ $$5101304215653624_7$$  This solution is $16$ digits long. As we did before for base-10, we can write out a sequence of the number of digits in each base's solution starting with base-2 $$6,6,9,2,14,16,4,5,42,18,...$$ $$\uparrow\ \ $$ $$\text{Base-}7\ \ $$ Another search on  quickly shows that these numbers are the multiplicative order of  $$5\ (\text{mod } 5\cdot7-1)\quad\text{or rather}\quad 5 \ (\text{mod }34)$$  $\bullet\textbf{ A Conjecture }\bullet$  The pattern might be clear now. After checking other cases, it seems that the smallest positive number in any base $B$ - which is $k$ times the value gotten by moving it's last digit to the front - has a number of digits equal to the multiplicative order of  $$k\ (\text{mod } Bk-1)$$ I can see how multiplicative order would be related to this problem. But I can't find an exact reason why this relationship should be so. Is there an intuitive reason?


I'm just trying to get a movie texture to play on an object - can't seem to get it to play in Blender 2.8 (when pressing space).    Can anybody suggest a solution?

I am trying to animate in 2d. I do it with planes that have textures on them. I recently came up with the idea of having a plane with an image sequence of mouths because animating actual lip syncing by hand takes too long and isn't really necessary for what I'm trying to acomplish. However, when playing back the animation in textured viewport shading the animated texture stays at the last frame until the animation stops. I can use the arrow keys and it works fine as well as scrubbing through the timeline, just not when playing back the animation with alt+a. Can anyone help me with this problem?


I am struggling to get this effect in Photoshop, but I am also unaware of what its technical name is. Can somebody please let me know what the name of the the effect that is being used below, that would be of great use to me!

How can I make this logo in Photoshop? Please teach me how its possible, or give me a hint what to search for to find tutorials for similar results.    Thank you.


I was thinking and this question came to my mind what is the relationship between hashCode() and equals()? Also, what is the significance of these methods? And, what are the requirements for implementing them?

What issues / pitfalls must be considered when overriding equals and hashCode?


I have laptops and electronics that i carry around daily. I use trains and cars as my means of transportation. Then a question popped out;   'is it OK to just leave my computer (or tablet, smartphone, etc) on the passenger seat when the seat has vibrations?? '  I'm pretty sure this depends on the type of computer, the amount of vibration, and etc...   I'm so much obssessed with this doubt that i always put cloth around my electronics and etc, to decrease the vibration!

I often travel by train with my laptop which has a mechanical hard drive.  I'm careful not to use the laptop during travel since there is a constant vibration that the drive experiences throughout. The magnitude is not much, but the vibration is prolonged (18 hours at a stretch).  Can prolonged vibration slowly kill the hard drive? Should I avoid taking my laptop when traveling by train? Or, if I do not use the computer and the head and the disk do not move during this period, is it safe?


I've installed Ubuntu 14.04 LTS recently on my laptop and I can't connect to the internet via WiFi. I've used Wireless Info Script recommended here:  And I got following results:   What should I do to make my WiFi work?

I'm new to Ubuntu. I installed it today, but the first thing I encounter is that I can only connect to the Internet through wifi.  Can someone help me?   iwconfig result :  eth0      no wireless extensions.  lo        no wireless extensions.   lspci:  00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM     Controller (rev 09) 00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port (rev 09) 00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09) 00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller (rev 04) 00:16.0 Communication controller: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 (rev 04) 00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 (rev 04) 00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04) 00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 (rev c4) 00:1c.1 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 2 (rev c4) 00:1c.3 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 4 (rev c4) 00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 (rev 04) 00:1f.0 ISA bridge: Intel Corporation HM76 Express Chipset LPC Controller (rev 04) 00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04) 00:1f.3 SMBus: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller (rev 04) 01:00.0 3D controller: NVIDIA Corporation GF117M [GeForce 610M/710M/820M / GT 620M/625M/630M/720M] (rev a1) 03:00.0 Network controller: MEDIATEK Corp. MT7630e 802.11bgn Wireless Network Adapter 04:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. Device 5289 (rev 01) 04:00.2 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 0a)   lspci -nnk | grep 0280 -A2:  03:00.0 Network controller [0280]: MEDIATEK Corp. MT7630e 802.11bgn Wireless Network Adapter [14c3:7630]     Subsystem: Foxconn International, Inc. Device [105b:e074] 04:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. Device [10ec:5289] (rev 01)


I will be away until this Sunday.  I will be available Sunday afternoon 2 PM to 3 PM.  Please correct this if there are any corrections required. Kindly explain the rule for help in understanding its use.

Possible Duplicate:          Please kindly advise me on the correct usage of till/until when talking about period of time. For example:     This offer is valid from Apr 21st until/till Apr 28th.   Also, I would be grateful if you could tell me what variants are possible if I want to squeeze this phrase into a small area? How can I make it shorter? That is, what parts can be omitted? The suffixes (st, th)?  For example:       Apr 21 - 28


Whether any massless spin 1/2 particles cannot have charge? If so, why?

Are there any massless (zero invariant mass) particles carrying electric charge?  If not, why not? Do we expect to see any or are they a theoretical impossibility?


Videos requires to install plugins to play media files of the following type: MPEG-1 Layer 3 (MP3) decoder

I would like to install the restricted extras package, which I didn't select during the install. How can I do that?        is a meta-package that installs:         Support for MP3 and unencrypted DVD playback   Microsoft TrueType core fonts   Flash plugin   codecs for common audio and video files


In answering , I proposed the following command   \newcommand{\testa}{%   \ifmmode     ^{12}\text{CO(1-0)}%   \else     $^{12}$CO(1-0)%   \fi }   But @egreg pointed out that I should be writing either:  \newcommand{\egrega}{%   \relax   \ifmmode     ^{12}\text{CO(1-0)}%   \else     $^{12}$CO(1-0)%   \fi }   or  \DeclareRobustCommand{\egregb}{%   \ifmmode     ^{12}\text{CO(1-0)}%   \else     $^{12}$CO(1-0)%   \fi }   and proposed I test things out in an array environment to see what happens.  \[\begin{array}{c}   \testa \end{array}\]   Sure enough, \testa results in the following warning:  ! Missing $ inserted. <inserted text>                  $ l.42   \testa  ?    whereas the two command \egrega and \egregb work as expected.  I wasn't happy with just this.  My understanding of robustness is quite shacky.  And, while I've read various posts such as , I still felt a bit in the dark.    So, I tried a different approach.  I tried writing  \[\begin{array}{c}   \ifmmode{Math}\else{NOT MATH}\fi \end{array}\]   Really, I don't why I did this.  I expected to the same error as with the faulty version of the command.  But instead I didn't get an error at all.  Instead, I got the following unexpected and erroneous result:    Clearly something is going very wrong here, and not in any way I anticipated.  If instead I write   \[\begin{array}{c}   \relax\ifmmode{Math}\else{NOT MATH}\fi \end{array}\]   or precede the \ifmmode by anything else to be processed, all seems to go well.  What am I failing to understand here?

I’m struggling with getting \ifmmode to work correctly when used inside an array environment which is inside a displaymath environment.  Here is a minimal example:  \documentclass{article}  \newcommand{\signal}[1]{%   \ifmmode     1#1   \else     2$#1$   \fi }  \begin{document} \begin{displaymath}   \begin{array}{cc}     \signal{a} \signal{b} & \signal{c} \signal{d} \\   \end{array} \end{displaymath} \end{document}   This example generates the following output:        Why doesn’t all invokations of \signal detect math-mode?


When executing sudo apt-get update I get the following error   Err http://ppa.launchpad.net trusty/main amd64 Packages                           404  Not Found Err http://ppa.launchpad.net trusty/main i386 Packages                            404  Not Found Ign http://ppa.launchpad.net trusty/main Translation-es_ES                      Ign http://ppa.launchpad.net trusty/main Translation-es                         Ign http://ppa.launchpad.net trusty/main Translation-en                         Ign http://ppa.launchpad.net trusty/main Translation-es_ES                      Ign http://ppa.launchpad.net trusty/main Translation-es                         Ign http://ppa.launchpad.net trusty/main Translation-en                         Ign http://ppa.launchpad.net trusty/main Translation-es_ES                      Ign http://ppa.launchpad.net trusty/main Translation-es                         Ign http://ppa.launchpad.net trusty/main Translation-en                         Ign http://ppa.launchpad.net trusty/main Translation-es_ES                      Ign http://ppa.launchpad.net trusty/main Translation-es                         Ign http://ppa.launchpad.net trusty/main Translation-en                         Descargados 2.981 kB en 22seg. (131 kB/s)                                       W: Imposible obtener http://ppa.launchpad.net/jconti/gnome3/ubuntu/dists/trusty/main/binary-amd64/Packages  404  Not Found  W: Imposible obtener http://ppa.launchpad.net/jconti/gnome3/ubuntu/dists/trusty/main/binary-i386/Packages  404  Not Found  E: Algunos archivos de índice fallaron al descargar. Se han ignorado, o se han utilizado unos antiguos en su lugar   What should I do to fix it?

PPA seems to be constantly offline. Whenever I use sudo apt-get update, this error is shown:  W: Failed to fetch http://ppa.launchpad.net/ 404  Not Found   How do I fix these errors?


I am using selenium and testNG framework for my project.  Now what is happening is each class is opening up a browser and then run its methods, eg, if I have five classes, then five browsers will open simultaneously and then run the tests. I want to Open Browser at the start once and run all the methods and then close it.  public class openSite { public static WebDriver driver; @test public void openMain() {   System.setProperty("webdriver.chrome.driver","E:/drive/chromedriver.exe");   WebDriver driver = new ChromeDriver();   driver.get("http://vtu.ac.in/"); } @test //Clicking on the first link on the page public void aboutVTU() { driver.findElement(By.id("menu-item-323")).click(); } @Test //clicking on the 2nd link in the page public void Institutes() { driver.findElement(By.id("menu-item-325")).click(); }   Now What I want is the testNG should open browser once and open vtu.ac.in once and then execute the methods aboutVTU and Institutes and give me the result

This has been asked a million times on the web, but there's no clear cut answer. I tried "-browserSessionReuse" today without any luck; my tests keep spawning new browser windows.  X:\QA\Automation\SELENIUM_SERVER>java -jar selenium-server-standalone-2.8.0.jar -log "log.txt" -browserSessionReuse -forcedBrowserMode "*googlechrome" <snip> 13:42:25.923 INFO - Will recycle browser sessions when possible.   Maybe it's how I'm starting Selenium in my .py files?  sel = selenium('localhost', 4444, "*chrome", 'http://server/') sel.start()   ...perhaps I'm doing too many server starts?


This is the setup I'm planning to use: Camera is an Olympus OMD E-M10 II, the lens is a Bower 500 mm f/6.3 using a Bower T mount to micro four thirds adapter.  The cause for my concern is that I plan to mount this on a tripod, which requires putting the camera on the tripod, since the lens does not have a tripod mount on it.  This in turn means the camera has to support the entire weight of the lens: about 1 lb 6 oz.  If it's necessary for getting an answer, I'd estimate the center of gravity of the lens is between 3 and 4 inches from the mount.  Am I safe mounting this lens on the camera body, and then placing the camera on a tripod?

I've been wondering why I've never seen any official specifications of the maximum allowed torque that can be exerted upon lens mounts. It seems to me like a very useful specification, but I can't seem to find it from any manufacturer.  indicates that there might be no specifications for Nikon mounts. Are there really no manufacturer that publish these specification of their mounts?


Now we have a nice side-by-side diff in the 'suggested edits' review pages, and as an , could something similar be made available as an option when editing a post?  It wouldn't need to be interactive - a button to get the side-by-side diff of the current state of your edit, versus the original would do.  This would be useful when shuffling lots of whitespace around - a final check that you haven't broken some embedded code.  A workaround at the moment is to submit the edit, then check the side-by-side view in the edit history.

Being a foreign language speaker (or writer and reader to be more exact) I would prefer to see the changes in a side by side diff tool.  The current format with the two above each other doesn't make it easy to recognize the improvements.


On trying to edit a comment after the 5 minute grace period, I get an error message of the form Error editing  comment : write_failed. I wasn't able to get a screenshot as it was visible for only a few seconds.   This should be replaced with the a proper pop-up stating "Comments cannot be edited after 5 minutes of posting" like in the case of the full site.  Version : 0.1.18  Update  Here is a screenshot of the error message. I'm on version 0.1.31

The Android app shouldn't offer the "edit" option for comments after the 5 minute window.  Currently, the app will give you the menu, allow you to click through and edit it, only to give you a "write_failed" error after submitting. For non-mods, who have a five-minute edit window, it makes no sense to offer the option in the first place.  Edit: Additionally, if you try to discard the edit, the app crashes.  Update:


an image is better than a thousand words:    Original title:

Recently, the TeX.SE question  got onto the Hot Network Questions list.  Like many questions on TeX.SE, it contains some TeX markup in its title.  Unfortunately, on , this markup gets parsed and rendered as math:    I propose that either:   the entire Hot Network Questions sidebar should be excluded from MathJax parsing by styling it with the tex2jax_ignore class, or at least, any hot questions from TeX.SE should be so excluded from MathJax parsing.   Or I suppose we could always implement , which asks for all questions with TeX in the title to be excluded from Hot Network Questions entirely.  That might be throwing out the baby with the bathwater, though.    Ps. This issue is partially masked by , which causes MathJax not to be rendered in many elements that are hidden by default and revealed using jQuery .show(), such as all but the first five questions in the Hot Network Questions sidebar.  The  user script contains a generic fix for that bug, so users who have it installed will see this issue more frequently, but it occurs even without SOUP whenever a question with TeX markup in the title happens to show up among the top five hot questions that are always visible by default.


Take it easy, I'm a n00b. I get this error when I'm trying to initialize an environment to get a project going. I've scoured through many stack overflow and GitHub (Usage/request) before I decided to post here. I updated pipenv and even updated by python up to 3.7 from 3.6. I've been at it for 2 hours but I decided I may need your help.   pipenv run python3 Creating a virtualenv for this project… Pipfile: /home/user1/Pipfile Using /usr/bin/python3 (3.6.7) to create virtualenv… ⠙ Creating virtual environment... ✘ Failed creating virtual environment  [pipenv.exceptions.VirtualenvCreationException]:   File "/home/user1/.local/lib/python3.6/site-packages/pipenv/cli/command.py", line 408, in run [pipenv.exceptions.VirtualenvCreationException]:       command=command, args=args, three=state.three, python=state.python, pypi_mirror=state.pypi_mirror [pipenv.exceptions.VirtualenvCreationException]:   File "/home/user1/.local/lib/python3.6/site-packages/pipenv/core.py", line 2310, in do_run [pipenv.exceptions.VirtualenvCreationException]:       three=three, python=python, validate=False, pypi_mirror=pypi_mirror, [pipenv.exceptions.VirtualenvCreationException]:   File "/home/user1/.local/lib/python3.6/site-packages/pipenv/core.py", line 574, in ensure_project [pipenv.exceptions.VirtualenvCreationException]:       pypi_mirror=pypi_mirror, [pipenv.exceptions.VirtualenvCreationException]:   File "/home/user1/.local/lib/python3.6/site-packages/pipenv/core.py", line 506, in ensure_virtualenv [pipenv.exceptions.VirtualenvCreationException]:       python=python, site_packages=site_packages, pypi_mirror=pypi_mirror [pipenv.exceptions.VirtualenvCreationException]:   File "/home/user1/.local/lib/python3.6/site-packages/pipenv/core.py", line 935, in do_create_virtualenv [pipenv.exceptions.VirtualenvCreationException]:       extra=[crayons.blue("{0}".format(c.err)),] [pipenv.exceptions.VirtualenvCreationException]: Traceback (most recent call last):   File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main     "__main__", mod_spec)   File "/usr/lib/python3.6/runpy.py", line 85, in _run_code     exec(code, run_globals)   File "/home/user1/.local/lib/python3.6/site-packages/virtualenv.py", line 26, in <module>     import logging ImportError: bad magic number in 'logging': b'\x03\xf3\r\n' Error in sys.excepthook: Traceback (most recent call last):   File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook     from apport.fileutils import likely_packaged, get_recent_crashes   File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in <module>     from apport.report import Report   File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in <module>     import apport.fileutils   File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in <module>     from apport.packaging_impl import impl as packaging   File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 24, in <module>     import apt   File "/usr/lib/python3/dist-packages/apt/__init__.py", line 26, in <module>     from apt.package import Package   File "/usr/lib/python3/dist-packages/apt/package.py", line 24, in <module>     import logging ImportError: bad magic number in 'logging': b'\x03\xf3\r\n'  Original exception was: Traceback (most recent call last):   File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main     "__main__", mod_spec)   File "/usr/lib/python3.6/runpy.py", line 85, in _run_code     exec(code, run_globals)   File "/home/user1/.local/lib/python3.6/site-packages/virtualenv.py", line 26, in <module>     import logging ImportError: bad magic number in 'logging': b'\x03\xf3\r\n'  Failed to create virtual environ   ment.

What's the "Bad magic number" ImportError in python, and how do I fix it?  The only thing I can find online suggests this is caused by compiling a .py -> .pyc file and then trying to use it with the wrong version of python. In my case, however, the file seems to import fine some times but not others, and I'm not sure why.  The information python's providing in the traceback isn't particularly helpful (which is why I was asking here...), but here it is in case it helps:  Traceback (most recent call last):   File "run.py", line 7, in <module>     from Normalization import Normalizer


When I use two variables in a for loop with different conditions two conditions like I have used below i<3,j<2 the for loop is always executing till the second condition fails.  #include<iostream> #include<conio.h> using namespace std ; int main() { int i,j ; for(i=0,j=0;i<3,j<2;i++,j++) {     cout<<"hello" ; } getch() ; return 0 ; }    In that code, hello is printed 2 times. Why?  If I use i<3,j<10, "Hello" is printed 10 times. I can't understand why the first condition is being neglected. Is it compiler dependent or something else?  Every thing works normal if I replace with conditions like || (OR) or &&(AND).An other thing is that I cannot initialize i and j in the for loop itself, it is showing me an error, but works fine when I declare variables in C style or one variable outside the for loop, why is it so?  Compiler I have used is Orwell Dev C++. Thanks in advance.

How does the comma operator work in C++?  For instance, if I do:  a = b, c;     Does a end up equaling b or c?   (Yes, I know this is easy to test - just documenting on here for someone to find the answer quickly.)  Update:  This question has exposed a nuance when using the comma operator.  Just to document this:  a = b, c;    // a is set to the value of b!  a = (b, c);  // a is set to the value of c!   This question was actually inspired by a typo in code.  What was intended to be  a = b; c = d;   Turned into  a = b,    //  <-  Note comma typo! c = d;


I'd like to know how to show the blue "notification" dot on a tab. Something like this  But every page I search, says something about pinning, and chrome deleted this function. Well, how is Reddit doing it then (while it's not being pinned as well)? Does someone know? It will obviously have to be JavaScript. I basically only use Chrome, so another question would be, do other browsers also have such functionality?

I have a web application that's branded according to the user that's currently logged in. I'd like to change the favicon of the page to be the logo of the private label, but I'm unable to find any code or any examples of how to do this. Has anybody successfully done this before?  I'm picturing having a dozen icons in a folder, and the reference to which favicon.ico file to use is just generated dynamically along with the HTML page. Thoughts?


Before I was learning about gradient descent, but now I understand this. Now, I have a problem with the backpropagation algorithm. I know the idea - minimalize error in multilayer neural network using chain rule. However, I don't understand the role of the derivative of the sigmoid function. This derivative is described in the algorithm. What is the point of this? Can you explain this step by step using simple language?

I try to understand role of derivative of sigmoid function in neural networks.    First I plot sigmoid function, and derivative of all points from definition using python. What is the role of this derivative exactly?    import numpy as np import matplotlib.pyplot as plt  def sigmoid(x):     return 1 / (1 + np.exp(-x))  def derivative(x, step):     return (sigmoid(x+step) - sigmoid(x)) / step  x = np.linspace(-10, 10, 1000)  y1 = sigmoid(x) y2 = derivative(x, 0.0000000000001)  plt.plot(x, y1, label='sigmoid') plt.plot(x, y2, label='derivative') plt.legend(loc='upper left') plt.show()


I have run the following lines in my console (once a jquery script has been loaded), and received the following results:  $(this) > [Window] $(this) != $(this) > true $(this) == $(this) > false $(this) === $(this) > false   And I don't know what steps to take to figure out what is going on. My guess is that there is some object that holds a time based value which is changing, but I wonder if it's something different. I will try to compare the values in the meantime, but I was hoping someone might understand what is going on here.  Edited to address the point that I was unaware of the underlying implementation of $(arg). I did not know that it returned a new reference object. Therefore, I don't believe this is a duplicate of "How to determine equality for two JavaScript objects?".

A strict equality operator will tell you if two object types are equal. However, is there a way to tell if two objects are equal, much like the hash code value in Java?  Stack Overflow question  is similar to this question, but requires a more academic answer. The scenario above demonstrates why it would be necessary to have one, and I'm wondering if there is any equivalent solution.


How can get I get the PID of the "firefox" process in C?  In this code, system only returns 0, indicating success. How can I get the PID?  int x = system("pidof -s firefox"); printf("%d\n", x);

I've got a utility that outputs a list of files required by a game.  How can I run that utility within a C program and grab its output so I can act on it within the same program? UPDATE: Good call on the lack of information.  The utility spits out a series of strings, and this is supposed to be portable across Mac/Windows/Linux.  Please note, I'm looking for a programmatic way to execute the utility and retain its output (which goes to stdout).


The variance of a t-distribution is given by df/(df-2), hence the t-distribution with 1 and 2 degrees of freedom have no defined variance. Yet these distributions do exist and can be drawn, so one would say that their variances can be calculated. I hope somebody can explain this without using too much mathematics, as my skills in mathematical statistics are poor.

From the distribution density function we could identify a mean (=0) for Cauchy distribution just like the graph below shows. But why do we say Cauchy distribution has no mean?


I've learned at school, that the electromagnetic radiation consists of photons. And all the frequencies of the wavelengths of photons define electromagnetic spectrum. The lower wavelengths are ionizing radiation. In the middle of the spectrum there is the visible light, and above that infrared, microwave, and radio waves.  But the thing nobody told me, is that: How is it possible to imagine a wave? I don't think, that the photon is physically moving sideways, and that is called the waving. But what is it then?  The explanation of the wavelength is, that it is a spatial period of the wave—the distance over which the wave's shape repeats. But what is this wave exactly? How can a single photon has it?

At the end of this nice video (), she says that  is a chain reaction of electric and magnetic fields creating each other so the chain of wave moves forward.  I wonder where the  is in this explanation. What is the relation between electromagnetic wave and photon?


I have the following variable I want to pass to a prepare statement: $subject. It is done using PDO. Unfortunately it is being passed in with single quotes around it.Example is that i pass in maths and the query uses 'maths' instead. I have tried other answers such as bindParam, bindValue as well as specifying it is a string attribute, however I cannot get it to work. Thanks in advance if anyone knows what is wrong My code is below.  $query = "SELECT * FROM :subject;";         $sql = $connection->prepare($query);         $sql->bindParam(':subject', $subject);          try{                             $sql->execute();         }catch(Exception $e){             echo $e;         }   And i get the following error:  exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''maths'' at line 1' in D:\xampp\htdocs\acards\functions.php:18 Stack trace: #0 D:\xampp\htdocs\acards\functions.php(18): PDOStatement->execute() #1 D:\xampp\htdocs\acards\getMathsQuestions.php(13): Functions->getFeed('maths') #2 {main}[]

Why can't I pass the table name to a prepared PDO statement?  $stmt = $dbh->prepare('SELECT * FROM :table WHERE 1'); if ($stmt->execute(array(':table' => 'users'))) {     var_dump($stmt->fetchAll()); }   Is there another safe way to insert a table name into a SQL query? With safe, I mean that I don't want to do  $sql = "SELECT * FROM $table WHERE 1"


I was reading about microcontroller interrupts and how they work, but I can't figure out how the context switch really happens. Can someone please explain it to me in more detail?

I am talking about things at the core level.   As far as I understand, the controller core just executes instructions which are fetched from the memory (Fetch - Decode - Execute). When an Interrupt arrives, how does the core/ALU decide to jump to the ISR?   Because we, or the compiler, don't add any instruction to poll the interrupt status - then how does it know that an interrupt needs to be served?


I've just downloaded Minecraft and I wanted to install Minecraft Forge, but it said I needed to go to bin folder than to minecraft.jar.  I don't have minecraft.jar, only having  versions, magic, launcher, launcher.pack.izma and launcher_profiles.json

I've recently changed to the new Minecraft launcher, and I have noticed a change in the .minecraft folder layout. I can no longer install mods just by copying it over into the versions/1.6.1 jar file, as this file refreshes every time it is launched.  For those who don't know what I am talking about, here is the new layout:    I am specifically trying to install Optifine, which does work with 1.6.1. Where do I drag in the mod files now? I can't seem to find a jar file that is suited to it, except in the version folder, but as I stated above, this refreshes every time.  After copying a recent version and renaming it in the version folder, I get this error in the development console:   Unexpected exception refreshing version list java.lang.IllegalArgumentException: Version '1.6.1' is already tracked     at net.minecraft.launcher.updater.VersionList.addVersion(VersionList.java:91)     at net.minecraft.launcher.updater.LocalVersionList.refreshVersions(LocalVersionList.java:44)     at net.minecraft.launcher.updater.VersionManager.refreshVersions(VersionManager.java:47)     at net.minecraft.launcher.Launcher$2.run(Launcher.java:164)     at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)     at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)     at java.util.concurrent.FutureTask.run(Unknown Source)     at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)     at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)     at java.lang.Thread.run(Unknown Source)


I receive a start and end DateTime.   From this, I want to create a List<DateTime> of all the dates that are between these two dates, but only on specified weekdays, such as the Monday.

Given a date range, I need to know how many Mondays (or Tuesdays, Wednesdays, etc) are in that range.  I am currently working in C#.


Sorry if this seems like a silly question, but I thought about this recently. What does it mean when one distro is based off of another? Is it just the shared package manager, or are other features picked up from Debian in Ubuntu? What does Ubuntu add on to Debian?

Ubuntu is a derivative of Debian. It uses the same package format.  In what ways is Ubuntu different from Debian?


I am applying for an MSc program and I need to find an advisor prior to sending in my application. I have heard conflicting advise regarding what to put in my first email. I would like some opinion on this matter.   Do I include my CV in the first email?   Do I mention my GPA?   Do I straight-up ask them if they are accepting students? Or, do I first attempt to establish a relationship?

When needing to ask a professor about something important and potentially delicate, what is an appropriate way to phrase the question or write the email?  Examples include:   Requesting a recommendation letter Asking for exceptions to policy (e.g., ignoring a course prerequisite, rescheduling an exam) Asking if you can do research with them, join a group, get into a program Scheduling a meeting, exam, or defense Letting them know about a change of plans Letting them know about a life event affecting your work or studies (e.g., wedding, funeral, sickness, vacation)


How would you prove that $$n^{\gamma} = m^{\gamma}$$ for every limit ordinal $\gamma$ and $n,m$ finite ordinals?   It's a rather short solution problem, but I can't construct any slick answer for it. I know very little about ordinal exponentiation, just that $\alpha^{\beta +1} = \alpha^{\beta}\cdot\alpha$ and that if there's a limit ordinal in the exponent we take the $\sup$.

I am trying to prove the following statement:  Suppose $ \alpha $ is a limit ordinal. Then $ 1 ^\alpha + 2^\alpha = 3^\alpha$.  I'm not sure how to grasp this. Obviously induction won't work, since the statement doesn't hold for non-limit $ \alpha $.  I tried to solve this for $ \alpha = \omega $, but then the statement gets trivial since both sides equal $ \omega $.  I would appreciate a hint


Is there a way to, in JavaScript running in the client's browser, access a local file for IO in following manner? The file is being appended to regularly (every ~25ms). We want to read every new line as it comes in. Preferably asynchronously (we get some kind of signal, or a callback executes) when anything is appended. Is this possible? If so, how?  My experience with Javascript is limited to D3, so a basic explanation on how or why/why not this is feasible would be appreciated. I can totally understand this not being possible due to security reasons.  EDIT: Just to make it clear, the file is on the clients computer. The file is just a text file. The process appending to it is a native process on the client's machine.

Is there local file manipulation that's been done with JavaScript? I'm looking for a solution that can be accomplished with no install footprint like requiring .  Specifically, I'd like to read the contents from a file and write those contents to another file. At this point I'm not worried about gaining permissions and am just assuming I already have full permissions to these files.


I have finally finished my login and register form WITH e-mail verification and I am SO happy! I am just not sure if my form is secure enough. I've used htmlspecialcharacters() on all user inputs and used placeholders in SQL queries. Is this enough to stop attacks on my form? Please help, as all answers are appreciated. Thanks! This is the code for my register form:   <?php include_once 'compat.php'; $user = 0; $pass = 0; $mail = 0; if($_SERVER['REQUEST_METHOD'] == 'POST' && !empty($_POST['mail']) && !empty($_POST['user']) && !empty($_POST['pass'])) {      function an($subject) {         if(ctype_alnum($subject)) {             return true;         }     }      if(an($_POST['user']) && strlen($_POST['user']) <= 20) {         $user = htmlspecialchars($_POST['user']);     }     else {         echo 'username is invalid (a-z A-Z 0-9 and less than 20 characters, please)
';     }     if(filter_var($_POST['mail'], FILTER_VALIDATE_EMAIL) && strlen($_POST['mail']) <= 255) {         $mail = htmlspecialchars($_POST['mail')];     }     else {         echo 'email is invalid
';     }     if(strlen($_POST['pass']) <= 255) {         $pass = htmlspecialchars($_POST['pass']);     }     else {         echo 'password must be less than 255 characters
';     }     if($pass && $user && $mail) {         $hash = md5(rand(0, 1000));         require_once('db.php');         $sth = $db->prepare("                                 INSERT INTO user_info (username, password, email, hash)                                 VALUES (:username, :password, :mail, :hash)                 ");         $sth->bindValue(":username", $user, PDO::PARAM_STR);         $sth->bindValue(":password", password_hash($pass, PASSWORD_DEFAULT), PDO::PARAM_STR);         $sth->bindValue(":mail", $mail, PDO::PARAM_STR);         $sth->bindValue(":hash", $hash, PDO::PARAM_STR);         $success = $sth->execute();         echo 'You have been successfully signed up :)! To activate your account, click the link in your e-mail account (check your spam box if you don\'t get the e-mail!)
                 The last step to activating your account is clicking this link!:
                 http://localhost/verify.php?mail=' . $mail . '&hash=' . $hash . '
                 ';     } } ?>

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


In my book I found a few of weird symbols:        They are used as mark of ellipse, parabola and hyperbola, respectively (E-like, P-like and H-like letters in these images). How to get them in LaTeX (and by the way, what's their name)?

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


If I have the equation $ax^2+ay^2+bx+cy+d=0$ how do I get the equation where the circumference goes through the points P = (1,1), Q = (−1,−1) and   R = (−1,1)   I have it in mind to solve it with a matrix, but the instructions seem confusing to me, can I get some help?

Find the equation of the circle $x^2 +y^2 +ax +by = c$ passing through points $(6,8), (8,4), (3,9)$.   How do I go about solving this? I don't have a textbook assigned so I'm not even sure what this relates to, but its the beginning of linear algebra. so I guess I'm supposed to construct some kind of system of equations...


I have strings stored in SQLite database which are shown in an Activity. the problem is if I compare the text of the button with a string value it returns false while equals show it matches. I am curious to know who it is returning false while they are both the same.  I have tried and tostring methods.   while (result.moveToNext()) {   Button btn = new Button(this);  btn.setWidth(100);  btn.setHeight(40);  //    btn.setSingleLine(); //keep text in single line don't break big words  //    btn.setAutoSizeTextTypeUniformWithConfiguration(1, 15, 1,  //          TypedValue.COMPLEX_UNIT_DIP);  messageReceived = result.getString(1).trim();  btn.setText(result.getString(1).trim());    String btnText = btn.getText().toString().trim();    String Value = Boolean.toString(btnText == messageReceived);  Toast toast = Toast.makeText(this, Value, Toast.LENGTH_LONG);  toast.setGravity(Gravity.CENTER, 5, 5);  toast.show();   if (messageReceived.equals(btnText)) {   Toast toast2 = Toast.makeText(this, "matched", Toast.LENGTH_LONG);   toast2.setGravity(Gravity.LEFT, 0, 0);   toast2.show();  } else {   Toast toast2 = Toast.makeText(this, "Not Matched", Toast.LENGTH_LONG);   toast2.setGravity(Gravity.LEFT, 0, 0);   toast2.show();  }    Toast.makeText(this, "A: " + btn.getText() + " B: " + messageReceived, Toast.LENGTH_LONG).show();   btn.setOnClickListener(this);  grid.addView(btn);   //messageReceived="pungi";   if (btnText == messageReceived) {   btn.setBackgroundColor(Color.YELLOW);  }   }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


This question is quite specific but I am not sure which verb tense I should use when committing/checking in code.  If I fix a bug and checking in the code, should I write:     Fixes bug on feature A Fixed bug on feature A   I always use past tense because the bug was fixed before I check in but it looks a bit strange when I look at file history.  Should I use one over the other and why?

In software engineering we use version control systems. Every time we check in modifications we usually leave a message with a summary of change. The question for me has always been: what is the most appropriate and practical tense and form for these messages? Examples:   Changed the function argument type to int Function argument type changed to int Function argument type is changed to int Function argument type has been changed to int Function argument type is now int   By "practical" I mean, because most messages are in the same form, they should be succinct, to the point, technical/formal. Best candidate in this regard is probably (2). Sometimes it is tempting to use (5) but you end up flooding your message log with "now", which is not nice. (4) is too long although looks (to me) appropriate in many cases. And finally, (1) and (3) feel wrong somehow, although (1) especially is a widely used one in programming, as far as I can tell.  Any thoughts, suggestions?  Edit: some other forms found by some googling:   Change the function argument type to int Changing ... Changes ...


When reviewing low quality posts this question appeared  . The question shows no research and no code that has been tried by the asker.  I want to recommend that the post be deleted, but with what reason? The post is, in my opinion, "off topic" as it asks for a solution but not help on a piece of code. None of the "off topic" options seem relevant.   seems relevant. Its answer recommends flagging with "This question does not show any research effort ..." but no such flag option is available to me.

I am a little confused about what do with questions that are just asking      "I want this and that (...) and I want it to look exactly like that   (...) please help"   without showning ANY own effort?  According to  those kind of answers are not welcome  also the  says those questions should not be asked:     Don't ask about...   Questions you haven't tried to find an answer for (show your work!)   But does this mean that I should flag those kind of "helpdesk" questions or not? And if yes as what? low quality ? flag for moderator attention ? Or is just adding a kind comment asking for the asker's own attempts enough?


I noticed that when a single runtime executable is saved from the BGE, the file has the default blender logo.  Is there anyway to change this to the logo of my game?  I looked at this question:  but the answer wasn't very helpful for me.  If somebody could explain how to do this is a lot of detail, that would be great!

I am wondering if and how to add your own picture here.


I have recently installed ubuntu 15.04 dual boot with windows 10. but my wifi is not enabled in ubuntu...is there need to install wifi driver in ubuntu...or suggest me command to enable wifi..  shubham@shubham-HP-Notebook:~$ lspci -nnk|grep 0280 -A2 04:00.0 Network controller [0280]: Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01)     Subsystem: Hewlett-Packard Company Device [103c:804a]     Kernel driver in use: bcma-pci-bridge shubham@shubham-HP-Notebook:~$

I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible.   What are the steps to install Broadcom wireless drivers for a BCM43xx card?  I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc.    lspci -vnn | grep Network showed:   Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b]      iwconfig showed:  lo        no wireless extensions. eth0      no wireless extensions.   NOTE: Answer below is updated every time new information is added and confirmed working.


If this were the case, their pension increase could have been   insufficient to raise their standard of living.   When do we use "If this were the case..."? If there are multiple cases(reasons), then we use "If this were the case..."? In that case, it would have been: "If these were the cases...". When should we use "If this was the case..." and "If this were the case..."?

From my research online the correct way is to say "If I were you" and not "If I was you" because this is the "subjunctive mood".  However they don't say the underlying reason for it. They just say use "If I were you" when it is subjunctive.  What if I wanted to say "If he was you", should I use "if he were you" instead? Since most post talk about "If I.." I have no way to know what would be the correct way for "If he...", "If she..", etc.  I read that the subjunctive is a mood and not a Tense. With Tenses you know the conjugation. How does it work with the moods?  I found  which has a long list of conjugations, and it has "I were" for the Past subjunctive.   So, when I am saying "If I were you":   Am I using the "Past Subjunctive"?  And therefore I should also say "If he were you"?


Suppose $f, f_{1,\cdots,n}\in X^*$ where $X$ is a normed vector space. How to show that, if $\cap Ker f_i \subset Ker f$, then $f$ is a linear combination of $f_{1,\cdots,n}$?  I'm at a loss even for the classical linear algebra cases (where $X$ is a finite dimensional Euclidean spade with $\ell^2$ norm, so really don't know how to proceed for the more general cases.    EDIT  It seems I might want to relax the conditions a little here. So let's now assume $X$ is a Banach space.    EDIT The Banach space assumption can be dropped. Any normed vector space is okay.

I am trying to prove the following. I have seen it alluded to in other places of the internet (this site included) but without proof.  Let $L,L_1\ldots L_n$ be linear functionals on a vector space $X$. If $\bigcap_{i=1}^n ker(L_i) \subset ker(L)$ then there exists $t_i$ for  $i=1\ldots n \in \mathbb{R}$ such that $L = \sum_{i=1}^n t_i L_i$.   In other words, if the intersection of kernels of linear functionals is contained by the kernel of another linear functional then they are linearly dependent.  Related:


$1 = \sqrt{1} = \sqrt{(-1)^2} = \sqrt{-1}\sqrt{-1} = i\cdot i = -1$. I know the mistake is here $\sqrt{(-1)^2} = \sqrt{-1}\sqrt{-1}$ because everything else seems right to me, but I don't understand why?  I guess this is the correct way : $\sqrt{(-1)^2} = |\sqrt{-1}| |\sqrt{-1}|$ ?

I know there must be something unmathematical in the following but I don't know where it is: \begin{align} \sqrt{-1} &= i \\\\\ \frac1{\sqrt{-1}} &= \frac1i \\\\  \frac{\sqrt1}{\sqrt{-1}} &= \frac1i \\\\  \sqrt{\frac1{-1}} &= \frac1i \\\\  \sqrt{\frac{-1}1} &= \frac1i \\\\  \sqrt{-1} &= \frac1i \\\\  i &= \frac1i \\\\  i^2 &= 1 \\\\  -1 &= 1 \quad !!? \end{align}


In elementary physics courses one is taught that energy is a measure of an object's ability to do work (this in itself seems a little flaky as how does one then define exactly what "work" is, other than stating that when a force acting on an system causes a displacement of that system, then the force is said to have done work on the system, or resorting to a tautological statement that describes it in terms of energy?!). Then in more advanced courses this description usually becomes more abstract in as such that energy is a conserved quantity attributed to a physical system, or an emergent quantity as a natural consequence of time translation invariance of a physical system (via Noether's theorem).  My question is, though, what exactly is energy? Is it possible to give a qualitative description of what it is a measure of?   I have read through the answers given in  and although they are somewhat useful, I feel that they don't really answer my question in terms of whether we can give a qualitative statement of what energy is, by this I mean, for example, velocity is a measure of the rate of change in position of an object per unit of time, is there a similar statement that can be ascribed to energy (or momentum for that matter)?

Some physical quantities like position, velocity, momentum and force, have precise definition even on basic textbooks, however energy is a little confusing for me. My point here is: using our intuition we know what momentum should be and also we know that defining it as $p = mv$ is a good definition. Also, based on Newton's law we can intuit and define what forces are.  However, when it comes to  many textbooks become a little "circular". They first try to define work, and after some arguments they just give a formula $W = F\cdot r$ without motivating or giving intuition about this definition. Then they say that work is variation of energy and they never give a formal definition of energy. I've heard that "energy is a number that remains unchanged after any process that a system undergoes", however I think that this is not so good for three reasons: first because momentum is also conserved, so it fits this definition and it's not energy, second because recently I've heard that on general relativity there's a loss of some conservation laws and third because conservation of energy can be derived as consequence of other definitions.  So, how energy is defined formally in a way that fits both classical and modern physics without falling into circular arguments?


Microsoft have recommendations around setting MAXDOP on various versions of SQL Server, but this (old) article raises some issues and recommends setting MAXDOP = 1 generally for SQL Server 2005 and indicates that some of the issues aren't fixed in SQL Server 2008.      Is there any indication that here are still problems with MAXDOP > 0 and are any DBAs out there not using 0 to reduce risks?

When setting up a new SQL Server, I use the following code to determine a good starting point for the MAXDOP setting:  /*     This will recommend a MAXDOP setting appropriate for your machine's NUMA memory    configuration.  You will need to evaluate this setting in a non-production     environment before moving it to production.     MAXDOP can be configured using:      EXEC sp_configure 'max degree of parallelism',X;    RECONFIGURE     If this instance is hosting a Sharepoint database, you MUST specify MAXDOP=1     (URL wrapped for readability)    http://blogs.msdn.com/b/rcormier/archive/2012/10/25/    you-shall-configure-your-maxdop-when-using-sharepoint-2013.aspx     Biztalk (all versions, including 2010):     MAXDOP = 1 is only required on the BizTalk Message Box    database server(s), and must not be changed; all other servers hosting other     BizTalk Server databases may return this value to 0 if set.    http://support.microsoft.com/kb/899000 */   DECLARE @CoreCount int; DECLARE @NumaNodes int;  SET @CoreCount = (SELECT i.cpu_count from sys.dm_os_sys_info i); SET @NumaNodes = (     SELECT MAX(c.memory_node_id) + 1      FROM sys.dm_os_memory_clerks c      WHERE memory_node_id < 64     );  IF @CoreCount > 4 /* If less than 5 cores, don't bother. */ BEGIN     DECLARE @MaxDOP int;      /* 3/4 of Total Cores in Machine */     SET @MaxDOP = @CoreCount * 0.75;       /* if @MaxDOP is greater than the per NUMA node        Core Count, set @MaxDOP = per NUMA node core count     */     IF @MaxDOP > (@CoreCount / @NumaNodes)          SET @MaxDOP = (@CoreCount / @NumaNodes) * 0.75;      /*         Reduce @MaxDOP to an even number      */     SET @MaxDOP = @MaxDOP - (@MaxDOP % 2);      /* Cap MAXDOP at 8, according to Microsoft */     IF @MaxDOP > 8 SET @MaxDOP = 8;      PRINT 'Suggested MAXDOP = ' + CAST(@MaxDOP as varchar(max)); END ELSE BEGIN     PRINT 'Suggested MAXDOP = 0 since you have less than 4 cores total.';     PRINT 'This is the default setting, you likely do not need to do';     PRINT 'anything.'; END   I realize this is a bit subjective, and can vary based on many things; however I'm attempting to create a tight catch-all piece of code to use as a starting point for a new server.  Does anyone have any input on this code?


While I'm using truncating in this method, it is somewhere wrong as in picture     public static List<Double> interp(DoubleUnaryOperator f, double l, double u, int n) {         double d = (u - l)/n;         List<Double> result = new ArrayList<>(n);         double net = f.applyAsDouble(l);         result.add(net);         int i = 0;         while(i+1 < n){          result.add(Math.floor(f.applyAsDouble(l + d)*100)/100);         l += d;          i++;         }      return result;    }  Who know how to truncate correclty? P.S. its important for the number be in two decimal places.

What I would like is a method to convert a double to a string which rounds using the half-up method - i.e. if the decimal to be rounded is 5, it always rounds up to the next number. This is the standard method of rounding most people expect in most situations.  I also would like only significant digits to be displayed - i.e. there should not be any trailing zeroes.  I know one method of doing this is to use the String.format method:  String.format("%.5g%n", 0.912385);   returns:  0.91239   which is great, however it always displays numbers with 5 decimal places even if they are not significant:   String.format("%.5g%n", 0.912300);   returns:  0.91230   Another method is to use the DecimalFormatter:  DecimalFormat df = new DecimalFormat("#.#####"); df.format(0.912385);   returns:  0.91238   However as you can see this uses half-even rounding. That is it will round down if the previous digit is even. What I'd like is this:  0.912385 -> 0.91239 0.912300 -> 0.9123   What is the best way to achieve this in Java?


I've been looking at the Mandelbrot set and playing around with the powers on it. In the sense that I know the equation is , and I've been changing up the $2$. As it happens gradual increases in the power have interesting effects, but I can't find much about them online. Why is it that the set uses the power $2$ as opposed to anything else?  Also, on a side note, does anyone know an explanation as to why the Mandelbrot set is shaped the way it is? With the different sections in it, and the symmetry about the real axis?  Thanks :)

Are there any well-studied analogs to the Mandelbrot set using functions other than $f(z)= z^2+c$ in $\mathbb{C}$?


I am trying to create a 2D game in Java where a user is prompted for a row width and column length. A 'world' object is created that looks like this when printed (where P is the player's character):  P--- ---- ---- ----   The user can then enter up, down, left, right or exit which should move the P around and do nothing if the move would move the character off the map. My issue is after I enter the width and length, I get the following error:  java.lang.NullPointerException at World.displayWorld(Driver.java:90) at Driver.main(Driver.java:28)   I believe this means that Java is seeing worldDimensions.length as empty/null?? I thought I was assigning a value to it when the world object is created.. Any guidance is much appreciated!  Here's my code:   import java.util.Scanner;  public class Driver {     public static void main(String args[]) {          //Create a scanner object         Scanner input = new Scanner(System. in );          boolean exit = true;          //Prompt user to enter world width and height         System.out.print("World width: ");         int userWidth = input.nextInt();         System.out.print("World height: ");         int userHeight = input.nextInt();          //Create a world object         World world1 = new World(userWidth, userHeight);         world1.displayWorld();          System.out.println("Possible inputs: up, down, left, right, exit");          while (exit = true) {             //display world             world1.displayWorld();              System.out.print("ACTION > ");             String userAction = input.next();              if (userAction == "up" || userAction == "down" || userAction == "left" || userAction == "right" || userAction == "exit") {                 switch (userAction) {                     case "up":                         world1.moveUp();                         break;                     case "down":                         world1.moveDown();                         break;                     case "left":                         world1.moveLeft();                         break;                     case "right":                         world1.moveRight();                         break;                     case "exit":                         exit = false;                         break;                 }             } else {                 System.out.println("Invalid Input. Possible inputs are: up, down, left, right, or exit.");             }         }      } }  class World {     static private char[][] worldDimensions;     static private int characterRow;     static private int characterColumn;      public World(int userWidth, int userHeight) {         char[][] worldDimensions = new char[userHeight][userWidth];         int characterRow = 0;         int characterColumn = 0;          for (int row = 0; row < worldDimensions.length; row++) {             for (int column = 0; column < worldDimensions[row].length; column++) {                 if (characterRow == row && characterColumn == column) {                     worldDimensions[row][column] = (char)                     'P';                 } else {                     worldDimensions[row][column] = (char)                     '-';                 }             }         }     }      public void displayWorld() {         for (int row = 0; row < worldDimensions.length; row++) {             for (int column = 0; column < worldDimensions[row].length; column++) {                 System.out.print(worldDimensions[row][column]);             }             System.out.println();         }     }      public void moveUp() {         if (characterRow - 1 >= 0) {             characterRow--;         }     }      public void moveDown() {         if (characterRow + 1 <= worldDimensions[0].length) {             characterRow++;         }     }      public void moveLeft() {         if (characterColumn - 1 >= 0) {             characterColumn--;         }     }      public void moveRight() {         if (characterRow + 1 <= worldDimensions.length) {             characterRow++;         }     } }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


System OS version & player media:Ubuntu 20.04 TLS amd64 of VLC&Kodi ;Windows 10x64 of PotPlayer e.g:  Installed VLC and its Blu-ray support on Ubuntu. I have used both Ubuntu and Windows and cannot parse the video. How can I do codec play for mkv video?

How to play blu ray .mkv files on Linux? e.g:1080p.BluRay.DD5.1.x264-NTb.mkv


I was trying to understand the architecture of transformers especially for the "Positional encoding" part and more precisely on "Why positional embeddings are summed with word embeddings instead of concatenation?" I came across an article saying that:  "Initially, if we pay attention to the figure 2, we will find out that only the first few dimensions of the whole embedding are used to store the information about the positions (Note that the reported embedding dimension is 512 despite our small toy example). And since the embeddings in the Transformer are trained from scratch, the parameters are probably set in a way that the semantic of words does not get stored in the first few dimensions to avoid interfering with the positional encoding."  Here, I have a little problem understanding what it means when it says "the parameters are probably set in a way that the semantics of words does not get stored in the first few dimensions?"  I did not really get it. I would be very grateful if someone could explain this to me or if anyone could recommend an article or any other resource that could help.

While reviewing the Transformer architecture, I realized something I didn't expect, which is that :   the positional encoding is summed to the word embeddings  rather than concatenated to it.               Based on the graphs I have seen wrt what the encoding looks like, that means that :   the first few bits of the embedding are completely unusable by the network because the position encoding will distort them a lot,  while there is also a large amount of positions in the embedding that are only slightly affected by the positional encoding (when you move further towards the end).               So, why not instead have smaller word embeddings (reduce memory usage) and a smaller positional encoding retaining only the most important bits of the encoding, and instead of summing the positional encoding of words keep it concatenated to word embeddings?


First of all, I know that this question has already been answer, but I need a little help. My "problem" is that I need to give more space to my root partition. This is my GParted screenshot:

Till today I was using ubuntu 13.04 in my windows7/ubuntu dual boot. Just now I have upgraded to ubuntu 14.04. My software updater showed an updates available message. I proceeded with  Install Now . Soon I got the following window.    Then I tried sudo apt-get clean as recommended. Nothing happened! Not even a window opened. Teach me deleting the temporary packages.   Deleting temporary files may not be highly helpful in case of further updates and installs for I don't have too much space left in my /. I wanna extend my / partition with the help of the unallocated space in my HD. The following is my Gparted window.       I got an answer . But it wasn't useful for me. I had two choices. But the answer wasn't working for both my chioces.  Choice 1: I may use the 4.25 GiB unallocated space to extend my /dev/sda10. To do so, I must need to move my linux-swap partition. But my Resize/Move option is disabled for the linux-swap partition. Choice 1 failed!   Choice 2: I may use the 14.35 GiB unallocated space instead. In this case I must move more than one partition. /dev/sda4  partition is the first on the list. Even that partition has the same problem. Resize/Move option is disabled. Choice 2 failed!  I am out of choices now.  What shall I do? Help me to extend my / with Gparted.


I am working on a system prototype which includes two ethernet switches (KSZ9896) to provide Ethernet Gigabit connectivity between several devices (let's call them slaves, from now on); every slave has it own PHY IC (dunno about the P/N, it's from Marvell).  Every switch has at least one slave connected to it, and both switches are connected together to access all slaves from an external computer (connected to one of the switches)  Switches and slaves are assembled in the same PCB, so they share the same ground reference.  After some investigation on the internet, I still have many questions to answer about this:   Is it needed to add Ethernet magnetics between switches? And from a switch to every slave connected to it?  Microchip recommends to use HX5008NL discrete magnetics with this switch (Magjack is not an option) and I see that the magnetics has a Chip side (PHY) and a Media Side (RJ45... that we don't have on our system).    As you can read, I just need to connect two PHYs in the same circuit, does it mean that I have to add 2xHX5008NL to connect both media sides?   If not, how can I connect both PHYs together (switch-slave or switch-switch) to work properly? In case of use discrete magnetics, could you recommend a circuit? Microchip shows a typical circuit  ( page 186), but it is slighly different from others I've seen on the internet. Many of them connect the common terminals capacitors (chip side) to 2.5V (I understand this is has to be the same voltage reference of PHY), and many others ties DP lines to GND through 50ohm resistors...   Thanks in advance.

In a (tentative) new design I want to connect two 100 Mbit/s Ethernet PHY similar to , separated by few inches on the same PCB, with same ground plane (but different power supplies). I have the choice of one of my PHY, but the other is embedded in an as-yet-unspecified PCIe to Ethernet IC (perhaps Gigabit but used in 100 Mbit/s mode), and it is critical that this PHY thinks there is a bona fide 100 Mbit/s Ethernet connection.  I could use the following         – Schematic created using   but I would like to achieve the same without the magnetics, in order to save on cost, purchasing headaches, and if at all possible power consumption.  I can imagine an RC network, perhaps as simple as in this , found thanks to a ; or maybe engineered with attenuation and lowpass, but that will not emulate the fact that with real magnetics, when there is a negative pulse on TX1P, there is a positive pulse on TX1M and RX2M. I am uncertain about if that would prevent some PHYs from working normally.  Anything to suggest that one is confident will work for practically any PHY around?


I was trying to create a Kali installation suite on my 16 GB sandisk pendrive. I used the dd command and umount to mount the iso into my USB. After the installation is complete I formated my pendrive and now it shows it has only 10 GB of usable space. How to format it properly so that i can use the entire space?

I followed this commandline method() — since ubuntu studio was different from original ubuntu, and the options were not available in GUI version —to format a USB stick, but I hadn't read after the part that required me to wait, and as a result my USB stick doesn't operate now. However, when I do plug it in, lsblk, shows that my USB is connect, however it's inoperable.     How can i recover my USB stick?


The cline between the colored cells 1 and 2 in the example below has been overridden by the cellcolor command.  I was wondering whether there exists a way to make the line separating these two cells on top of the yellow color. Any help is highly appreciated.   Thanks   Hartmut Helmut  \documentclass[a4paper,11pt]{article}  \usepackage[utf8x]{inputenc} \usepackage[english]{babel}  \usepackage[usenames,dvipsnames,svgnames,table]{xcolor} \usepackage{multirow}  \begin{document}  \begin{center} \begin{table} \begin{tabular}{|c|c|c|c|c|c|c|}\hline      Days  & 3 & 6 & 9 & 12 & 15 & 18 \\      \hline\hline      \multirow{2}{*}{Project} & \multicolumn{4}{c|}{\cellcolor{yellow} 1} & & \\      \cline{2-7}   & & & \multicolumn{4}{c|}{\cellcolor{yellow} 2}  \\  \hline \end{tabular} \end{table} \end{center}  \end{document}

So I need to make a colored table with multirows, together with the use of partial horizontal lines. I used \cline which does not work: the \cellcolor-command overwrites the line.  told me to change it to \hhline which will not be overwritten by \cellcolor. Instead, \hhline overwrites the color.  To make it more clear:  Without color:  \documentclass{article}  \usepackage{colortbl} \usepackage{multirow}  \begin{document}    \begin{tabular}{|c|c|}     \hline     \bfseries ColumnOne & \bfseries ColumnTwo\\ \hline     First data & 932\\ \hline      & 239\\ \cline{2-2}  % or \hhline{|~|-|}      & 137\\ \cline{2-2}  % or \hhline{|~|-|}     \multirow{-3}{*}{More data} & 319\\ \hline     Last data & 132\\ \hline   \end{tabular}  \end{document}     With color: Using \cline  \documentclass{article}  \usepackage{colortbl} \usepackage{multirow}  \begin{document}    \begin{tabular}{|>{\columncolor{red}}c|>{\columncolor{blue}}c|}     \hline     \bfseries ColumnOne & \bfseries ColumnTwo\\ \hline     First data & 932\\ \hline      & 239\\ \cline{2-2}      & 137\\ \cline{2-2}     \multirow{-3}{*}{More data} & 319\\ \hline     Last data & 132\\ \hline   \end{tabular}  \end{document}    Makes the lines in the right column disappear.  Using \hhline  \documentclass{article}  \usepackage{colortbl} \usepackage{multirow} \usepackage{hhline}  \begin{document}    \begin{tabular}{|>{\columncolor{red}}c|>{\columncolor{blue}}c|}     \hline     \bfseries ColumnOne & \bfseries ColumnTwo\\ \hline     First data & 932\\ \hline      & 239\\ \hhline{|~|-|}      & 137\\ \hhline{|~|-|}     \multirow{-3}{*}{More data} & 319\\ \hline     Last data & 132\\ \hline   \end{tabular}  \end{document}    Creates white lines on the left column.  Is there any possible way on how to resolve this?


Browsing on Wi-Fi, I can access stuff in my room even though my Wi-Fi has to go through a wall to reach me.  But how is this possible, when the Wi-Fi wavelength is 12 cm, as cited ?  AFAIK, for light, or any form of electromagnetic wave, to "bend" around walls, the wavelength must be bigger than the window size. So how can Wi-Fi bend around windows? And how can it penetrate walls?  As a broader question, when can electromagnetic waves penetrate and not penetrate walls?  The question is different from .  That question already presumes that radio waves and gamma rays can travel through walls.   I do not know whether light can "bend" or penetrate walls. Also, I question Wi-Fi signals, which I believe are in the infrared spectrum only.

and they are on opposite ends of the electromagnetic spectrum, then why can't light travel through walls which is right in the middle of the spectrum?    This question has already been asked . However, I am not entirely satisfied by the answer given on that page which relies on fanciful analogies and metaphors of ants, elephants etc. I am looking for a better explanation.    I think the crux of the matter, and my dilemma, relates to formula for . This is a well known formula used to explain the fact that low frequency waves have more penetration than high frequency waves.     But then how come gamma waves have such high penetration?     Are there some assumptions behind derivation of this formula which break when we consider very high frequency waves?    Or, are there some new factors that need to be taken into account as we move into the high frequency regime?     If given a radio source and a gamma source of equal intensity, then will the radio source have more penetrability than the gamma source per formula for ? If not, why not?  Thanks for all those who posted answers to this question. The answer being proposed is that light waves have the right energy to interact with atoms and electrons in the matter and thus get absorbed. This is a quantum mechanical explanation. The skin depth, on the other hand, is derived purely on basis of classical electrodynamics. So I see there are two mechanisms at work here? Does anyone agree with this? If so, the net absorption will be the sum of absorption due to skin effect + absorption due to atomic physics. Now if we take gamma rays - agreed there will be no absorption due to atomic physics but there should be absorption in accordance with skin effect. And so I come back to original problem.


I notice that almost all camera use either a proprietary Li-ion battery or AA size battery for power.  May I know what is the reason for not having a camera that have USB port that can be connect to a Power Bank for supply? (since there are so many Power Bank of different mAh nowadays)

I made some scripts on my Raspberry Pi to automate a daily shot at a specific hour.  My DSLR is plugged in through USB. I thought this would keep its battery charged, but no.  Is there really no way automate a DSLR to shoot every 24 hours without having to pick it up, charge/replace its battery, and put in back on the same spot?


In Beamer presentation I have itemized block:  \begin{itemize}     \item object     \item type     \item action \end{itemize}   I was wondering if I could put one symbol - } that will spawn to several lines and then write one description after it. something like this:    I was looking for it but was not able to find anything similar. So any suggestion would be helpful.

I have an itemized list:  \begin{itemize}     \item Lorem     \item Ipsum     \item Sit     \item Dolor     \item Amet \end{itemize}   I want to create an accolade on the right side of 'Lorem' and 'Ipsum', and add a bit of text at the point of the accolade. The level of this text should be between the first and the second line. How can I get this done?


While reading a book on statistics, I encountered the following:  $$f(x) = \mathop{\text{argmin}}\limits_c E_{Y|X}([Y-c^2]|X=x)\tag{1}$$ which somehow equates to $$f(x) = E(Y|X=x)\tag{2}$$ How do we get from result $(1)$ to $(2)$?

In machine learning, we let $X$ be a real-valued input vector and $Y$ be a real number output, with joint distribution $P(X,Y)$. We are looking for a function $f(X)$ for predicting $Y$ given the values of $X$. In most of machine learning problems, we give penalty for each time that the prediction is wrong. The loss function is defined as follows:  $L(Y,f(X))=(Y-f(X))^2$.   The expected square prediction error is given as:   $$EPE(f) = E(Y-f(X))^2 = \displaystyle\int [y-f(x)]^2P(dx,dy). $$    The book I'm reading says: By conditioning on $X$, we can write EPE as $EPE(f) = E_XE_{Y|X}((Y-f(X))^2|X)$, and eventually getting a solution that is $f(x) = E(Y|X=x)$.   I'm not sure I follow what happened in these steps. Please help me with the derivation.  Thanks


I prefer uniformity and would rather see all  in the default style (generally all major SE sites use their own styles, the sites in beta state can't yet). This doesn't appear to be possible to achieve without creating site-specific network filter rules.  Another large voting-driven website Reddit allows disabling custom "subreddit" (i.e. "sub-site") styles site-wide in account settings — Stack Exchange should consider implementing this option as well.

Is it possible to switch a certain Stack Exchange site's interface (as a personal preference) to the theme used by beta sites?  Some sites have flashy decorations or unreadable fonts (I prefer to disable antialiasing on fonts). It would be nice to have an option to see a site with the "beta" theme.  If there's a solution using custom styles, I would accept that as an answer.