I have a question in ring theory whose answer I am looking for.  Consider R to be a Euclidean Domain such that R is not a field. Then is polynomial ring R[X] is always a PID or not.  Attempt : R is ED implies R[X] is ED and R is ED implies R is PID. But can someone please tell what can I say about R[X] from it.

I've just read a proof of the statement:  Let $R$ be a commutative ring. If $R[X]$ is a principal ideal domain, then $R$ is a field.  In one part of the proof there is a step which I don't understand. I'll copy the proof: Let $u\in R$ be non-zero. Then using the principal ideal property, for some $f\in R[X]$ we have $\langle u,X\rangle = \langle f \rangle \subseteq R[X]$. Therefore, for some $p,q∈R[X], u=fp$ and $X=fq$. By properties of degree we conclude that $f=a$ and $q=b+cX$ for some $a,b,c\in R$. Substituting into the equation $X=fq$ we obtain $X=ab+acX$ which implies that $ac=1$, i.e. $a\in R^\times$, the group of units of $R$. Therefore, $\langle f\rangle =\langle 1\rangle=R[X]$. Therefore, there exist $r,s\in R[X]$ such that $ru+sX=1$ and if $d$ is the constant term of $r$, then we have $ud=1$. Therefore $u\in R^\times$. Our choice of $u$ was arbitrary, so this shows that $R^{\times}⊇R \setminus \{0\}$, which says precisely that $R$ is a field. I don't understand this: "$X=ab+acX$ which implies that $ac=1$, i.e. $a\in R^\times$, the group of units of $R$. Therefore, $\langle f\rangle = \langle 1\rangle =R[X]$." Why does the fact that $a=f$ is a unit implies that $\langle f\rangle = \langle 1\rangle$? I would appreciate if someone could explain this to me. Thanks in advance.


In Centos 8.2 I have configured a bridged wifi interface (ath9k) as a wireless access point in NetworkManager (nmcli).  When using WPA or WEP security it works fine, but I need an open wifi network.  I have scoured the internet and tried every 802-11-wireless-security setting in the NetworkManager documentation attempting to disable wireless security.  Setting key-mgmt=none just enables WEP and I can't find any setting to disable WEP or wireless security in general. I'm just looking for confirmation if this is possible to create an open wifi network without using another solution other than nmcli.  If someone has done this I would be happy seeing their .. $ nmcli con show wlan0

Is there a way to create a hotspot that doesn't have a password?  The "hotspot command"  of nmcli :   wifi hotspot [ifname ifname] [con-name name] [ssid SSID]        [band {a | bg}] [channel channel] [password password]   does not allow to have a empty password: it gives  Error: Invalid 'password': '' is not valid WPA PSK.   I guess there is a way to edit the configuration files used by nmcli to generate a hotspot to turn it into a password-free hotspot.  If nmcli is not able to do this, what other tools would do it?   Thank you


I am having a very hard time trying to get the color turquoise . When converting from rgb to cmyk they are nothing close. How do I get the color of turquoise I see on my monitor to be printed on cards? What is the best method to see the conversion on my monitor?

I designed a mockup on my LG monitor. When I view the same design on another monitor that I own, the colors seem drastically different. I reset both of the monitors to their factory defaults, but still the issue persists. I'm wondering if some of my clients might dislike my designs because of this. What should I do?  How can I make sure that what I design is what my client sees?  Even worse still, I've realized that my laptop is showing different colors too.


Can I use a 5V 1A usb adapter to power a 5V 500mA lamp?  The lamp describes 5V 500mA as max. rated power input

Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.


My text defines the equation for the probability of getting exactly $k$ independent successes in an experiment of $n$ trials, with $p$ being the probability of the success event and $q$ being the probability of failure ($1-p$) is:  $b(k; n, p) = {n \choose k}(p)^k(q)^{n-k}$  The part to the right of the binomial coefficient makes sense to me intuitively. What I don't understand is why we're multiplying it all by $n \choose k$. Could someone please help clarify this for me?

How should I understand the difference or relationship between binomial and Bernoulli distribution?


I am trying to retrieve a number of rows from a mysql DB, some of which containing emojis, through the following function:  <?php ini_set('mssql.charset', 'UTF-8'); //$mysqli->query("SET NAMES 'utf8'"); $mysqli->query("SET character_set_client=utf8mb4"); $mysqli->query("SET character_set_connection=utf8mb4"); $mysqli->query("SET character_set_results=utf8mb4"); $mysqli->set_charset("utf8"); $sth = $mysqli->query($query); if (!$sth) error_log("error Json query: $query"); $rows = array();  while($r = mysqli_fetch_assoc($sth)) {     $rows[] = $r; } //var_dump($rows); print json_encode($rows, JSON_NUMERIC_CHECK | JSON_UNESCAPED_UNICODE); ?>   Yet each emoji occurrence is substituted by a variable number of question marks, yet if I conversely execute the query of the php script directly on Sequel Pro, the emojis show correctly. Apparently there is therefore some error in the function above, but I tried anything, as you may see, without success. How should the query be configured instead?

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


I have an LG V40, and in both Android 9 and 10, it seems that the "Screen Recording" app is always running, and not possible to keep it Stopped. Greenify shows it as running in "Foreground":  If I force hibernation, seconds later it will be running in Foreground again. It is not possible to disable this app, and it requires access to Camera and Microphone:  These permissions cannot be removed either:   Should I be concerned? Is there any way I can fully disable this app? My OS is European.

Is there a way to temporarily disable apps I downloaded from the Google play store without having to uninstall them?


I'm experiencing WiFi disconnects after suspending my laptop or closing the lid. I'm relatively new to Linux, so after I restarted my PC the problem was fixed again. However, it still says that I have disconnected from the internet whenever I suspend/close the lid of my laptop. I've noticed that I actually haven't disconnected from the internet and I can still access websites. The menu no longer shows a WiFi logo but shows two arrows in opposite directions and when you click on it the WiFi Networks are grayed out.

I am unable to connect to the internet via Ethernet or WiFi.  Let's fix the Ethernet issue, eh?  I just installed Ubuntu 12.04 on an HP Mini 1000.  Previously it had 11.04, and the Ethernet didn't have any issues then.  I am a Linux beginner, and I have been working on this issue for the past several days without any progress.    Here are some outputs:  $ sudo lshw -C network *-network                   description: Network controller    product: BCM4312 802.11b/g LP-PHY    vendor: Broadcom Corporation    physical id: 0    bus info: pci@0000:01:00.0    version: 01    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress bus_master cap_list    configuration: driver=b43-pci-bridge latency=0    resources: irq:16 memory:feafc000-feafffff *-network    description: Ethernet interface    product: 88E8040 PCI-E Fast Ethernet Controller    vendor: Marvell Technology Group Ltd.    physical id: 0    bus info: pci@0000:02:00.0    logical name: eth0    version: 00    serial: 00:25:b3:48:e7:60    capacity: 100Mbit/s    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation    configuration: autonegotiation=on broadcast=yes driver=sky2 driverversion=1.30 latency=0 link=no multicast=yes port=twisted pair    resources: irq:42 memory:febfc000-febfffff ioport:ec00(size=256)   lspci  00:00.0 Host bridge: Intel Corporation Mobile 945GSE Express Memory Controller Hub (rev 03) 00:02.0 VGA compatible controller: Intel Corporation Mobile 945GSE Express Integrated     Graphics Controller (rev 03) 00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03) 00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02) 00:1c.0 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 1 (rev 02) 00:1c.1 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 2 (rev 02) 00:1d.0 USB controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #1 (rev 02) 00:1d.1 USB controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #2 (rev 02) 00:1d.2 USB controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #3 (rev 02) 00:1d.3 USB controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #4 (rev 02) 00:1d.7 USB controller: Intel Corporation N10/ICH 7 Family USB2 EHCI Controller (rev 02) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2) 00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 02) 00:1f.1 IDE interface: Intel Corporation 82801G (ICH7 Family) IDE Controller (rev 02) 00:1f.3 SMBus: Intel Corporation N10/ICH 7 Family SMBus Controller (rev 02) 01:00.0 Network controller: Broadcom Corporation BCM4312 802.11b/g LP-PHY (rev 01) 02:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8040 PCI-E Fast Ethernet Controller   Thanks for your help!


Two questions :   How I can write my images textures at the same time as .obj and .mtl? The linked files are missing. How I can write the files paths correctly.    I tested the file / external data but there isn't any changing.  Thank you for your replies  I try to make option copy, but it does not work, I do not understand.

I use Blender to render objects as this makes them look better. The problem is when I export one of my characters as an OBJ file and then import it back into Blender to render, the textures seem to not have been saved with it and the character's surface appears pink when clicking on 'Texture Solid'. At first I thought I accidentally pressed a button without realizing but, I sent the file to my friend and it was also pink for him so I began to think I was missing the texture. I have been scanning forums and found the suggestion of: File>External Data>Find Missing Files. However, this did not work either. I am completely and utterly stuck on what to do and my hobby is now hold up until I can fix it. The second image shows the problem I am having. The first image shows it's how some textures don't export with the file when I export the character from 'Roblox Studio'


What is the intuitive explanation for the CDF of any random variable to follow uniform distribution?  While i'm clear with the mathematical proof, I'm looking for an intuitive explanation to this.

I read  that given a sample $ X_1,X_2,...,X_n $ from a continuous distribution with cdf $ F_X $, the sample corresponding to $ U_i = F_X(X_i) $ follows a standard uniform distribution.  I have verified this using qualitative simulations in Python, and I was easily able to verify the relationship.  import matplotlib.pyplot as plt import scipy.stats  xs = scipy.stats.norm.rvs(5, 2, 10000)  fig, axes = plt.subplots(1, 2, figsize=(9, 3)) axes[0].hist(xs, bins=50) axes[0].set_title("Samples") axes[1].hist(     scipy.stats.norm.cdf(xs, 5, 2),     bins=50 ) axes[1].set_title("CDF(samples)")   Resulting in the following plot:    I am unable to grasp why this happens. I assume it has to do with the definition of the CDF and it's relationship to the PDF, but I am missing something...  I would appreciate it if someone could point me to some reading on the subject or help me get some intuition on the subject.  EDIT: The CDF looks like this:


Recently while I was practicing Python, I came up with the problem. I created two different empty lists one using list comprehension and next using the "multiplication" way. Structurally both the lists are similar. Afterwards, when I assign the value of array[0][0]=1 and try to print the list the result goes like this. a=[[0 for i in range(3)] for j in range(3)]  b=[[0]*3]*3  print(a) print("#####") print(b)   a[0][0]=1 b[0][0]=1 print("#################")  print(a) print("#####") print(b)    My problem is why on array b all the values at the beginning of each lists gets replaced by 1 whereas not in array a. I need a geniune answer for it.

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


Trying to buy a knife recently there are some that are $10, some $50 and all the way up to $300+. I understand that there are differences in the quality of the steel and its hardness and how long it holds its edge for. However there isn't a clear difference in features at the different price points apart from I assume more expensive works better somehow. For the non-specialist, by which I mean someone like me who cooks daily and would like a good tool but doesn't care about the marginal gains, what is the right level to buy?  I'm assuming like a lot of things there's an 80/20 principle where you get 80% of the benefits after a certain expenditure and then next few hundred bucks are squeezing out the last few percent

Many knife manufacturers provide the hardness value for the knife blade in the specifications - like 53HRC or 57 HRC.  What's the optimal hardness for kitchen knives? Do I always prefer the ones with higher hardness all else being equal?


What I can't understand is why the Stack Overflow senior community is hostile to newbies.  As much as I try to research my questions before asking and editing them well I always seem to get condescending comments or, worse, get my questions closed.  I think this kind of mentality has to stop as it doesn't foster a great learning environment.   Yes, I know some of us might not be as bright as some of you, but still it shouldn't allow you to put our questions down.

There is a distinct decline in the level of civility on all the sites here.  Some of this is due to new users coming in and posting spam and other nonsense, but the off-topic and downvote buttons are doing a pretty good job of keeping this under control. Unfortunately, a lot of this is coming from more experienced users, and the site's built-in moderation system does not (and probably cannot) handle this very well.  Folks are rushing to pound new users down with "this belongs on meta!", "this is off topic", "this is a duplicate!" and "read the Help!". (Which is correct, but should be done nicer) All this, of course, is accompanied by a flurry of downvotes.  This is not very welcoming to new users who don't know about meta, the Help, or what counts as off-topic. Now I am not proposing that we just allow off-topic, meta, or duplicate questions.  However, I think we could be gentler in the way we express these sorts of things.  Explain what meta and the FAQ are and provide useful links.  Just using please and thank-you when asking folks to read the FAQ or post something on meta would be an improvement.  I also think we could rein in the downvoting a bit.  Not that we shouldn't vote stuff down, but unless a new user's post is clearly spam, voting it down to -1 or -2 should be sufficient to send a message without piling on. I like Stack Exchange and I want it to become a resource for everyone, not just an elitist site for high-rep users on the sites.


I have recently upgraded my Ubuntu to 16.04.I was using 12.04. I am facing some issues with 16.04. Is it possible to downgrade to my old Ubuntu 12.04 without fresh installation.

I just installed a new version of Ubuntu and I want to roll it back to the previous version.  How can I do that? Is that even possible?


I struggle with the following statement :  Let $V$ an open connected set , $g$ a holomorphic function s.t  $V \subset \mathbb C$  and also  s.t $g$ is one-to-one then : $g^{-1} $ is also holomorphic  If anyone could help and explain how the fact of $g$ being only one-to-one prove that $g^{-1}$ is holomorphic . Is $g$ also a bijective function ? Any help would be appreciated , thanks in advance.

Suppose $U$ and $V$ be domains(i.e., open and connected) in $ \mathbb C$.Let $f\colon U \to V$ be a bijective holomorphic function. Show that the inverse of $f$ is also holomorphic.  By Open Mapping Theorem it is clear that $f^{-1}$ is also continuous. Please give some ideas to complete the proof.  Edit:I'm interested in a proof which comes as a corollary of  open mapping theorem


As you can see in the picture ,I want to be able to select a record type then the form that appears will depend on the record type selected , I will have two record types

I'm trying to create record Type selection screen in LWC, but getting this error  afterRender threw an error in 'c:createContact' [Cannot read property 'recordTypeInfos' of undefined]  HTML:  <template>     <lightning-combobox name="recordType" label="Record Type" placeholder="Choose Status"                         value={value}                          options={recordTypeId}>      </lightning-combobox> </template>   JS:  import { LightningElement, track, wire, api } from 'lwc'; import { getObjectInfo } from 'lightning/uiObjectInfoApi'; import CONTACT_OBJECT from '@salesforce/schema/Contact';  export default class CreateContact extends LightningElement {      @track statusOptions;     @track value;     @api objectApiName;      @track objectInfo;      @wire(getObjectInfo, { objectApiName: CONTACT_OBJECT,})     objectInfo;       get recordTypeId() {         // Returns a map of record type Ids          console.log(this.objectInfo);         const rtis = this.objectInfo.data.recordTypeInfos;         return rtis;     }  }


Since the film days we have used 0.03 CoC for determining depth of field and similar calculations. In digital terms, does this best match with 6 or 12 or 24 or 36Mpixel full frame sensors? If this matches with 12Mpix (a guess), then could you suggest a useful value of CoC for 36Mpix please?

I have been reading about depth-of-field and presume to have a sufficient understanding of what it means and how it is related to lens properties, lens aperture, focal length, sensor format size and probably even print dimensions in case the picture is being printed. I do have a question about how/if depth-of-field depends on the dimension of a pixel. Let me elaborate:  Given two sensors with differing pixel sizes: x and 4x, the latter sensor integrates more light per-pixel than the former, however, it might have a lower resolution if the sensor dimensions remain fixed. Theory suggests that the depth of field is determined by those circles-of-confusion which are very close to being an in-focus point, and this perhaps also means that these very small CoCs fall within the integration area of the same pixel. Now when a CoC becomes larger than a pixel (like also in the case of diffraction blur), there is some spreading of intensities among neighboring pixels and this would clearly lead to blur. However, if one was using the 4X sized pixel, even with a slightly larger CoC, the intensity would still integrate into the same pixel area, and would thus perhaps be in-focus? Is this the right assumption? And if so, is there any analysis of pixel-area dependence of depth-of-field? Moreover, depth-of-field is in some sense independent of the integration medium as it clearly occurs in analog film devices as well, so is there a trade-off or a difference in depth-of-field between film and digital cameras?  Please point me to the correct references for this question. Please correct me if there seems to be a fundamental issue with the assumptions made above.


Summary: My question is not about why I have not got the badge, but rather the misleading progress display.  There are quite some posts about this topic. Most of them are marked either duplicate or closed. This topic is slightly different here is why,  To get curious badge a user must Ask a well-received question on 5 separate days, and maintain a positive question record. Agreed!  The formula to calculate if I am eligible for this badge is total questions - negative questions - closed - deleted)/total questions >= 0.5. Totally fine!   The best example what I can give why I think the count is shown wrong is I can't have 7 apples out of 5! How can I have 29/5 on the badge? I think the way the numbers are displaying is misleading.  Here are the few questions which talk about this issue but they are answered with you don't have +ve track. This answer doesn't really help. Again, how can I have 29 apples out of 5?

I saw that it has been already reported that also they have earned courious badge but the badge has not been given. but their answers say that they must wait a day and the badge will be awarded.  In my case its 8/5 and it was 5/5 long time ago and I have never received a message telling that I have earned it. its just telling me that the next badge to be awarded is Curious badge.  this is my profile:


I am trying to fit a Poisson regression in some soccer matches. I want to be able to predict matches of the first league for a new season, which means that there will be some new teams that have been promoted from last seasons second league. Hence I am creating a data frame with all matches from last year's league 1 and League 2, and then I am doing a Poisson regression. My problem is that there is a team whos coefficient cannot be estimated (NA). How can I overcome this?  My code:  prepare_data =  function(dataframe) {      dataframe = dataframe[c("HomeTeam", "AwayTeam", "FTHG", "FTAG")]    dataframe.temp = dataframe[, c(2,1,4)]     names(dataframe.temp) = c("HomeTeam", "AwayTeam", "Goals")     dataframe = dataframe[c("HomeTeam", "AwayTeam", "FTHG")]   names(dataframe) = c("HomeTeam", "AwayTeam", "Goals")     dataframe = rbind(dataframe, dataframe.temp)     dataframe$Home<- rep(c(1,0), each = nrow(dataframe) / 2)     dataframe  }  # try to train model using two leagues mydata3a <- read.csv("https://www.football-data.co.uk/mmz4281/1718/E0.csv", header = TRUE, stringsAsFactors = TRUE) mydata3b <- read.csv("https://www.football-data.co.uk/mmz4281/1718/E1.csv", header = TRUE, stringsAsFactors = TRUE)  mydata3a = prepare_data(mydata3a) mydata3b = prepare_data(mydata3b)  mydata3 = rbind(mydata3a, mydata3b)  model <- glm(Goals ~ Home + HomeTeam + AwayTeam, family=poisson, data=mydata3)   and my problem is    AwayTeamWolves           NA    I cannot predict matches of Wolves.

I have a output variable and 1 categorical predictor and 3 continuous predictors.  dat=data.frame(IV = rnorm(9), group=c("A","A","A","B","B","B","C","C","C"),pred1=rnorm(9),pred2=rnorm(9),pred3=rnorm(9))   What is the recommended way to add the dummy variable and how does the interpretation of the output change with these 2 setups?  If I do this and include a single column for the dummy variable     lm(IV~factor(group)+pred1+pred2+pred3, data = dat)  lm(formula = IV ~ factor(group) + pred1 + pred2 + pred3, data = dat)  Coefficients:    (Intercept)  factor(group)B  factor(group)C           pred1           pred2           pred3          -0.3143          0.9496         -0.3502          0.1839         -0.5349         -0.4710     In the case above the results the groupB and groupC coefficients are RELATIVE to groupA.  OR if I don't want the results to be relative I can include groupA like this:  dat2 = cbind(dat[,c("IV","pred1","pred2","pred3")], model.matrix(~ factor(dat$group) - 1) ) lm(IV~., data = dat2)  Call: lm(formula = IV ~ ., data = dat2)  Coefficients:          (Intercept)                 pred1                 pred2                 pred3  `factor(dat$group)A`  `factor(dat$group)B`  `factor(dat$group)C`                -0.6645                0.1839               -0.5349               -0.4710                0.3502                1.2998                    NA     I have a few questions:   How does the interpretation of the intercept change between the 2 models? Why in the last model is the GROUP C coefficient "NA"?


I am currently starting to learn some QFT. And I am very confused by the fact that the freedom to choose a gauge for a theory controls the physical degrees of freedom.  Please correct me if i am wrong with the following because i think i might have internalized by myself undetected misconceptions.  The free electro-magnetic field for example has only two physical degrees of freedom, since electromagnetic waves are exclusively transversal waves so there are no longitudinal degrees of freedom.  The four-potential $A^\mu$ has four entries so with no further information $4$ degrees of freedom, so we need to relate the entries of $A^\mu$.  I do know and understand that the fields described by $F^{\mu\nu}$ are invariant under a transformation $G$ with $$ G:\quad A^\mu \longrightarrow A^{\mu} + \partial^\mu \phi $$ where $\phi$ is some arbitrary scalar field, which can be easily shown by explicitly writing out the field tensor.  Question: Why does the freedom to choose such a gauge cancel out 2 degrees of freedom ?

How do I definitively show that there are only two propagating degrees of freedom in the Lorenz Gauge $\partial_\mu A^\mu=0$ in classical electrodynamics.  I need an clear argument that   involves the equations of motion for just the potentials $A^0$ and $\mathbf{A}$, and not the electric and magnetic fields.   includes sources $\rho$ and $\mathbf{J}$ in the equations of motion.  This is to justify the assertion that there are degrees of freedom that decouple from the rest of system. does not critically rely on quantum field theoretic arguments (although any supplementary remarks are welcome).     To illustrate the level of clarity I expect, I provide an argument in the Coulomb gauge $\nabla\cdot \mathbf{A} = 0$:  Of the four field degrees of freedom, the gauge condition $\nabla\cdot \mathbf{A} = 0$ removes one degree of freedom (the longitudinally polarized EM waves).  To show that among the remaining three degrees of freedom only two are propagating, consider the field equations of motion in the Coulomb gauge:  \begin{align} \nabla^2 A^0 &= -\rho/\epsilon_0,\\ \big[\frac{1}{c^2}\frac{\partial^2}{\partial t^2}-\nabla^2\big]\mathbf{A}&= \mu_0 \mathbf{J}-\nabla \frac{1}{c^2}\frac{\partial}{\partial t}A^0. \end{align}  The first equation is NOT a wave equation for $A^0$, and thus does not propagate.  The final equation IS a wave equation, and describes the propagation of two degrees of freedom (Gauss' law in first eq. can be solved, and then inserted into the second equation to show that $\mathbf{A}$ only couples to the Solenoidal part of the current).


It´s summertime now where we live, and it can be pretty hot (30 degrees Celsius or 86 Fahrenheit). So we put our daughter of 5 month to sleep on her back without blanket or sleep sack.  However, she sometimes turn on her tummy in her sleep. Is that a concern ? Should we turn her back on her back ? Should we put a light blanket to prevent her from turning while sleeping ?

Our 3 months old baby is very keen on rolling over and being on his stomach. Most of the time he automatically rolls over in a few minutes after we put him on his back, including during bed time. Is this dangerous? We are particularly worried that   his nose maybe blocked when facing down it is said that SIDS risk increases when a baby sleeps on his stomach   If it is dangerous, how can we stop this, especially during bed time or other times when we can't watch him continuously?


I have dynamic HTML structure. Like this:
Lorem ipsum http://google.com dolour sit  amet
&nbsp;
   I want click this http link and other all links.  How can I find it and make clickable via jQuery?

I am using the function below to match URLs inside a given text and replace them for HTML links. The regular expression is working great, but currently I am only replacing the first match.  How I can replace all the URL? I guess I should be using the exec command, but I did not really figure how to do it.  function replaceURLWithHTMLLinks(text) {     var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/i;     return text.replace(exp,"$1");  }


I was going through this code :  https://raw.githubusercontent.com/douglascrockford/JSON-js/master/json_parse.js   All functions in this file are defined as   var foo = function() {}   instead of   function foo(){}   I am quiet aware of what each style represents and how to use them. However I am yet to see a convincing answer on what the advantage of using the first pattern over the second one is.  Is it just because.. "functions are first class objects .. they can be assigned and tossed around.. so why not??"  or is there some solid reason behind this ?

I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer used two ways of declaring functions and I can't work out if there is a reason behind it or not.  The two ways are:  var functionOne = function() {     // Some code };     function functionTwo() {     // Some code }   What are the reasons for using these two different methods and what are the pros and cons of each? Is there anything that can be done with one method that can't be done with the other?


When I look at a post I see a lot of blank areas.            App Version: 1.0.85 Device Manufacturer: OnePlus Device Model: ONE A2003 OS Version: 6.0.1 (31)

Since the last update (v1.0.85), I am getting all the question pages blank on the Android app. For those who are confused with the image, I'm using RtL (Right-to-Left) layout.        If I scroll down (quite a bit) I can see the question. But even then I cannot see the question title, the related comments or answers.         App Version: 1.0.85 Device Manufacturer: LGE Device Model: LG-D620   OS Version: 5.0.2 (152541901f156)


Using windows 10,1.16.40  and i cant find my folder in file explorer.  Have tried to use WIN+R and typing in %appdata% and all that kinda stuff. Hidden files is on. Tried different c combinations of folders (such as: Microsoft, windows etc ) still zero luck.

I have searched in %appdata%, pulling up the list of files there, but there is no file labelled .minecraft. Searching %appdata%\.minecraft returns "no results found".   I also opened Minecraft to click on the resources button and could not locate that either.


I have booked the flight ticket , but France VISA is Rejected for the Second time , i am Cluelesss  i have Booked the Cheaper flight tickets , which i was not aware of was it was NON-REFUNDABLE , and the VISA is been Rejected saying 'the Intentdent Stay was not Reliable '  My purpose of visit is specified properly as Honeymoon trip. I have given itinerary for the entire trip along with necessary accommodation and internal schengen travelling arrangements, i have provided Sponsorship letter from my parents along with bank statements and their passports. I am a Software Engineer, working at Banglore. I have submitted my Employee details from my office. Even the travel insurance and NOC from my wife's parents. All the documents specified in the list were presented. After my first rejection, i waited till my marriage completion and immediately after marriage i applied for marriage certificate and presented it for the reapplication of Visa. Even though i strived hard for getting all the documents ready both mine and my wife's Visa has been rejected. Visiting Europe countries is a dream for majority of people and i am one among them, especially the Eiffel tower in Paris being one among the Wonders of World also the Switzerland which is the top Honeymoon destination, one of the beautiful dream to be fulfilled, hence i have been struggling by applying for Visa, the second time but it has been rejected now, i am not able to understand the reason for  disapproval.  Please let me know if I have to submit any other documents that will help me get the visa , I will be happy to provide them immediately. I am ready to give confirmed receipt for booking and also any other document which they ask for.  I have paid 240+ Euros VFS charges for the visa i.e Rs.30,000 and visiting the VFS Global Office 4th time. Also most importantly I have already booked the flight and paid for my flight tickets which is around Rs.90,000 With lot of effort I have afforded this money and I hope France embassy understands and reconsiders our application to facilitate the visa process. I kindly request you understand my concern. Let me know the proper reason and the requirement of necessary document which i need to submit for my Visa Approval. I hardly have 10 days left from today for my flight which is booked on 28-11-2019(BLR-MCT-CDG with eTicket receipt:9102116368731,68732)with the return date being 13-12-2019.   My flight ticket is booked and that booked ticket is non-refundable , please consider my application (Please Find the attachments )the E-copy of the ticket is also attached in the mail   Hence please consider my urge and i request you kindly help me to facilitate the process as soon as possible.

Schengen refusal formulae can be difficult to understand sometimes.  Sometimes an applicant receives a refusal with:       Justification for the purpose and conditions of the intended stay was not reliable.     often accompanied by:       Your intention to leave the territory of the Member States before the expiry of the visa applied for could not be ascertained.   What is meant by this refusal reason?  What are they trying to say?


A well-known crank, let's call him "Wolfgang", uses ten different sock-puppets to dump his pseudo-scientific nonsense into several Stack Exchange sites. Every time another user, let's call him "Uwe", notices Wolfgang's questions or answers, he adds a comment "Warning: "Forte" is one of Wolfgang's ten sock-puppets, and discussing with Wolfgang is known to be pointless". Then Wolfgang changes the display name of his sock-puppet "Forte" to "Uwe", which not only confuses other readers, but makes commenting quite difficult for Uwe. Is this considered as acceptable behaviour, or is it something that moderators (have to?) deal with?

First of all, please note the precedent:  - Jeff himself has posted about a similarly troublesome account.  This is also tangentially related to   Check this guy out:    (no rhyme intended)  Over 9 pages of user accounts registered.  It looks like some have already been deleted, but type his name into the user search on SO right now and you'll see a full page of results, so there are at least 35 current accounts.  Let me be clear about this, I am very apprehensive about complaining about a specific user and would never start this type of discussion if I didn't think it was an extreme case.  People argue on SO (and probably the other trilogy sites), it's natural, and sometimes they get heated and/or spill over onto Meta - I'm not upset or offended by conflict, but this user's outbursts are completely random and unprovoked and usually off on a tangent, and I honestly think that the only logical conclusion here is that he/she/it is a serial troll.    Some of his answers (and note that these are all coming from different accounts):    Here he blasts the OP for "not knowing how to get anything done in Django" and picking the wrong tool, apparently.  This one is a random rant about error messages which has almost nothing to do with the question.  Another tirade, this time about surrogate keys, complete with cursing and anti-religion overtones.  Here he goes way off-topic, answering a question that the OP didn't ask.  Not so inflammatory this time but basically a non-answer, "you can't do it".  A less-useful (and wrong) duplicate of another answer, posted later.  I wonder who gave him the 1 upvote.  "The idiot who wrote this doesn't understand jack shit about the power of relational algebra." (Scary that this answer actually got 4 upvotes).  Basically a massive long-winded explanation of how what the OP wanted to do was impossible.  Posted 6 days after Quassnoi gave a perfectly serviceable answer that received 6 upvotes and an accept.  In here he basically says, several times, that everybody else is an idiot.  A rather pointless and unsubstantiated knock against OODBs.  Cursing and complaining about all the "mediocre" programmers.     So to summarize, we have someone who:   Answers with a combination of circumlocution, flowery prose, and four-letter words, typically only to explain that the question author is an idiot or that it's impossible to do what he's asking; Creates new accounts every day, sometimes multiple times per day, so it's not even worth the rep cost to downvote; Repeatedly posts comments as answers and even acknowledges that he's doing it and that it's frowned upon, but apparently doesn't seem to care. Actually has one account that's accrued over 500 rep (mostly from one-off upvotes), so he clearly knows how to register properly and even provide useful answers once in a while, but seems to create these rather obvious sockpuppet accounts to troll. Is submitting these troll answers to questions that are not even remotely controversial!   I suppose it's possible that whoever this is is creating all these accounts simply can't figure out how to use the login system properly, but seems more likely to me that he's creating throwaway accounts in order to escape culpability (downvotes) from his troll posts.    Thoughts?  Does my theory make sense?  Is it reasonable to want to do something about this, or am I making mountains out of molehills?  Assuming it's a reasonable complaint, can something be done about it, and is it appropriate to bring up the subject here on Meta?


Hello I would like to do one table like this:   \begin{table}[] \centering \caption{My caption} \label{my-label} \begin{tabular}{|l|l|} \hline \textbf{Strengths}     & \textbf{Weaknesses} \\ \hline items here             & more items          \\ \hline \textbf{Opportunities} & \textbf{Threats}    \\ \hline items                  & iteems              \\ \hline \end{tabular} \end{table}   I would like to do on each row of the table except the titles ones (Strengths, Weakness, Opportunities, Threats):  \begin{itemize}   \item One entry in the list   \item Another entry in the list \end{itemize}

I have the following (Non-working) example.  \renewcommand*{\arraystretch}{1.8} \begin{longtable}{lcl}     \caption{Summary of proven determinants for falling}\\ \toprule     \label{tab:FallPredictionVariables}     \textbf{Author} &\textbf{Subject count (M:F)} & \textbf{Determinants}\\     \midrule      \noindent Author 1 &     1780 (?) &      \begin{itemize}%[label={--},noitemsep,leftmargin=*,topsep=0pt,partopsep=0pt]         \item Recent falls (last 2 months)         \item Agitation         \item Frequent toileting         \item Visual impairment     \end{itemize}\\      \noindent Author 2 &     311 (?) &     \begin{itemize}%[label={--},noitemsep,leftmargin=*,topsep=0pt,partopsep=0pt]         \item Posture sway         \item Two or more falls in previous year         \item Low hand grip strength         \item Depressive state of mind     \end{itemize}\\         \bottomrule  \end{longtable}   However, it works OK outside a longtable environment:  \renewcommand*{\arraystretch}{1.8} \begin{table} \centering     \caption{Summary of proven determinants for falling}      \label{tab:FallPredictionVariables}     \begin{tabular}{lcp{60mm}}     \toprule     \textbf{Author} &\textbf{Subject count (M:F)} & \textbf{Determinants}\\     \midrule      \noindent Author 1 &     1780 (?) &      \begin{itemize}[label={--},noitemsep,leftmargin=*,topsep=0pt,partopsep=0pt]         \item Recent falls (last 2 months)         \item Agitation         \item Frequent toileting         \item Visual impairment     \end{itemize}\\      \noindent Author 2 &     311 (?) &     \begin{itemize}[label={--},noitemsep,leftmargin=*,topsep=0pt,partopsep=0pt]         \item Posture sway         \item Two or more falls in previous year         \item Low hand grip strength         \item Depressive state of mind     \end{itemize}\\         \bottomrule          \end{tabular}  \end{table}   As you can see in the picture below, it does what I'm expecting (except there is some vertical space over the first item that I would like to remove, and the solutions posted in  only seem to work for tabularx environments).    I'm unable to make my code work inside longtable, and I really need it (the complete table is very long).  Any ideas for both things:   To be able to have itemize inside longtable environment Eliminate the extra space for the first item   PS: This is the preamble for both examples:  \documentclass[a4paper,twoside,11pt,openright]{report} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage{longtable}   \usepackage[inline]{enumitem}    \usepackage{booktabs}  \begin{document} ... \end{document}


I need to input 2d array and make changes in it but the answer is always wrong. This is my code. r,c,obs = map(int, input().split()) k = [] h = [] for i in range(r):     for j in range(c):         k.append(0)     h.append(k)  for i in range(r):     for j in range(c):         print(h[i][j],end=" ")     print()  while obs > 0:     l, k = map(int, input().split())     h[l-1][k-1] = 1     obs -= 1  for i in range(r):     for j in range(c):         print(h[i][j],end=" ")     print()  My input is this - 5 4 4 3 2 3 4 4 2 5 2  According to the code my resultant matrix should be something like this - 0 1 0 0  0 1 0 0  0 1 0 1  0 0 0 0  0 0 0 0  But it is always resulting to this - 0 1 0 1  0 1 0 1  0 1 0 1  0 1 0 1  0 1 0 1  Can anyone tell me what is wrong here??

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


i made marshmellows, came out very well. i cut it and rolled in icing sugar, for a while i was good, but then it stated to absorb the icing sugar and marshmellows are now wet, b ut still in its shape. Can anybody give me a solution to clean, dry texture. Thanks, Jubi..

The recipe that I used did not call for cornstarch or corn syrup. The result is that they are slightly wet. Can I do anything to dry them up, such as dusting them with corn flour?  I did dredge them in a mixture of confectioners sugar and corn flour; it helped a little, but I think I will find a recipe that has corn starch in it for next time!


I am new here. I don't know if this problem is easy or not or is that suitable for this site or not. But I have difficulties dealing with it.   Let $A\subseteq \Bbb{C}$ be open and connected. Also let $f,g :A \longrightarrow \Bbb{C}$ be analytic functions such that $|f| + |g|$ is constant. How can I show that $f$ and $g$ are constant (if its true) ?

Let $f_1,f_2,\ldots,f_n $ be  analytic complex functions in domain $D$. and $f = \sum_{k=1}^n|f_k|$ is not constant.  Can I show the  maximum of $f$ only appears on boundary of $D\,$?


This is my Bullets class  package mainPackage;  import java.awt.Graphics; import java.awt.image.BufferedImage;  public class Bullets {      private double x;     private double y;     private BufferedImage bulletImage;     Bullets(double x, double y){         this.x = x;         this.y = y;         ImageLoader loader = new ImageLoader();         SpriteSheet ss = new SpriteSheet(loader.loadImage("/Pics/TheSpriteSheet.png"));         bulletImage = ss.grabImage(2, 1, 32, 32);     }      public void render(Graphics g){         g.drawImage(bulletImage, (int)x, (int)y, null);     }     public void tick(){         y--;     }     public double getX(){         return x;     }     public double getY(){         return y;     } }   Then I made my BulletQualities class  package mainPackage;  import java.awt.Graphics; import java.util.LinkedList;  public class BulletQualities {     Bullets b;     private LinkedList<Bullets> bulletList = new LinkedList<Bullets>();      public void addBullet(Bullets b){         bulletList.add(b);     }     public void tick(){   I get an error on this next line          for(Bullets bullet:bulletList){                 if(bullet.getY() == 0)                 removeBullet(bullet);             bullet.tick();         }     }     public void render(Graphics g){         for(int x = 0;x < bulletList.size(); x++){             bulletList.get(x).render(g);         }     }     public void removeBullet(Bullets bullet){         bulletList.remove(bullet);     } }   This is my error message:   Exception in thread "Thread-4" java.util.ConcurrentModificationException     at java.util.LinkedList$ListItr.checkForComodification(Unknown Source)     at java.util.LinkedList$ListItr.next(Unknown Source)   Then it just showed the lines with errors. I have no idea why It's not working. Please help me. It would mean a lot. :-)  Oh, I almost forgot, this is my removeBullet method from my bulletQualities class:  public void removeBullet(Bullets bullet){     bulletList.remove(bullet); }

We all know you can't do the following because of ConcurrentModificationException:  for (Object i : l) {     if (condition(i)) {         l.remove(i);     } }   But this apparently works sometimes, but not always. Here's some specific code:  public static void main(String[] args) {     Collection<Integer> l = new ArrayList<>();      for (int i = 0; i < 10; ++i) {         l.add(4);         l.add(5);         l.add(6);     }      for (int i : l) {         if (i == 5) {             l.remove(i);         }     }      System.out.println(l); }   This, of course, results in:  Exception in thread "main" java.util.ConcurrentModificationException   Even though multiple threads aren't doing it. Anyway.  What's the best solution to this problem? How can I remove an item from the collection in a loop without throwing this exception?  I'm also using an arbitrary Collection here, not necessarily an ArrayList, so you can't rely on get.


$$ \sum_{i=1}^N\left\lfloor\frac{N}{i}\right\rfloor $$ Is there a closed form expression to the above sum? (Mathematica doesn't give me anything)

I realize that there is probably not a closed form, but is there an efficient way to calculate the following expression?  $$\sum_{k=1}^n \left\lfloor \frac{n}{k}\right\rfloor$$  I've noticed $$\sum_{k=1}^n \left\lfloor \frac{n}{k}\right\rfloor = \left\lfloor\frac{1}{2}\sum_{k=1}^{\left\lfloor\frac{n}{2}\right\rfloor} \left\lfloor\frac{n}{k}\right\rfloor\right\rfloor + \sum_{k=1,\ odd(k)}^n \left\lfloor \frac{n}{k}\right\rfloor$$  But I can't see an easy way to let the second term enter in a recursion.


I was benchmarking my WD 500 GB HDD in Ubuntu Disks several times and saw that the read speeds started at 140 MB/s, but it consistently would gradually decrease by a few MB/s with seemingly no floor. The same was for write speeds, but to a dramatically greater extent. What is the meaning of that? I am installing Ubuntu on it now; what might I expect the impacts will be on daily use as time goes on (i.e. how will that behavior manifest in daily use)?

I use HD Tune to measure performance of the hard drive.  The tests typically take 2-3 minutes and the transfer rate of a regular hard drive decreases dramatically as the test comes to a close.    However, the SSD drive performance stays the same over (pic below) the life of the test.  This happens on all my computers.  Why is that?


I am writing test class how to cover scheduler class in test class.  Class:  global class updatecontactaccount implements database.batchable<sobject>,schedulable{     global database.querylocator start(Database.Batchablecontext BC)     {         string query = 'select id,name,accountnumber,(select id,lastname,accountid from contacts) from account where name = \'testaccount\'';         return database.getquerylocator(query);     }      global void execute(Database.Batchablecontext BC, List<account> Scope){         list<contact> listcon = new list<contact>();         map<string,contact> oldmap = new map<string,contact>();         map<string,contact> newmap = new map<string,contact>();         account acc = [select id,name,(select id, lastname from contacts) from account where name=: 'BICS'];             for(contact a : scope[0].contacts){                 oldmap.put(a.lastname,a);             }             for(contact c : acc.contacts){                 newmap.put(c.lastname,c);             }             for(contact c : oldmap.values()){                 if(!newmap.containskey(c.lastname))             {             c.accountid = acc.id;                 listcon.add(c);                                                     }             }             system.debug('contact:'+listcon);             update listcon;     }     global void finish(Database.Batchablecontext BC){     }  global void execute(schedulablecontext sc){     updatecontactaccount up = new updatecontactaccount();     database.executebatch(up);     } }   Test Class:  @istest public class Updatecontactaccount_Test {     static testmethod void testbatch(){         account a = new account();         a.name = 'testaccount';         insert a;         contact c = new contact();         c.lastname = 'Test';         c.accountid = a.id;         insert c;         account acc = new account();         acc.name = 'test11';         insert acc;         contact con = new contact();         con.lastname = 'Test11';         con.accountid = acc.id;         insert con;         updatecontactaccount up = new updatecontactaccount();         database.executebatch(up);      } }

global class ScheduleBatch implements Schedulable {      global void execute(SchedulableContext sc) {       BatchArticleUpdateCase batch = new BatchArticleUpdateCase();        database.executebatch(batch);     }     Public static void SchedulerMethod(){      } }


I'm trying to create a new variable array out of the unique values that are in another array but I'm not getting the desired result.  Original Array  # echo ${owner[*]} 390920ad-2858-e651-a4af-a9eaa6acaebb 390920ad-2858-e651-a4af-a9eaa6acaebb e14c2413-7179-44f8-dfc3-b8624dcb10bb 390920ad-2858-e651-a4af-a9eaa6acaebb e14c2413-7179-44f8-dfc3-b8624dcb10bb 390920ad-2858-e651-a4af-a9eaa6acaebb e14c2413-7179-44f8-dfc3-b8624dcb10bb 390920ad-2858-e651-a4af-a9eaa6acaebb 390920ad-2858-e651-a4af-a9eaa6acaebb 390920ad-2858-e651-a4af-a9eaa6acaebb e14c2413-7179-44f8-dfc3-b8624dcb10bb 390920ad-2858-e651-a4af-a9eaa6acaebb e14c2413-7179-44f8-dfc3-b8624dcb10bb 390920ad-2858-e651-a4af-a9eaa6acaebb 390920ad-2858-e651-a4af-a9eaa6acaebb 390920ad-2858-e651-a4af-a9eaa6acaebb 390920ad-2858-e651-a4af-a9eaa6acaebb 0a452389-5ed2-e46f-ad15-cc538c82650d 4232f23d-ed48-4b14-c0ea-aa911fd24920 8ee1b05f-2473-4c37-bfc5-ae393921b939   Command I'm using  uniq=($(printf "%s\n" "${owner[@]}" | sort -u))   Issue (It's storing all the unique values as a single value under index 0)  # echo ${uniq[0]} 0a452389-5ed2-e46f-ad15-cc538c82650d 390920ad-2858-e651-a4af-a9eaa6acaebb 4232f23d-ed48-4b14-c0ea-aa911fd24920 8ee1b05f-2473-4c37-bfc5-ae393921b939 e14c2413-7179-44f8-dfc3-b8624dcb10bb # echo ${uniq[1]}  #   Anyone know a better way of grabbing the unique values from this array?  Using bash on SmartOS (Similar to Solaris)  EDIT  I've tried the following as well which will store each value under it's own index number but it does not remove the duplicate values:  uniq=($(printf "%s " "${owner[@]}" | sort -u))

If I have a string "1 2 3 2 1" - or an array [1,2,3,2,1] - how can I select the unique values, i.e.  "1 2 3 2 1" produces "1 2 3"    or  [1,2,3,2,1] produces [1,2,3]   Similar to uniq but uniq seems to work on whole lines, not patterns within a line...


I have an array as follow: The first key element is a date with the format dd-mm-yyyy  Array (     [08-12-2015] => Array         (           ------------         )     [07-12-2015] => Array         (           ------------         )     [09-12-2015] => Array         (           ------------         ) )   Is it possible to sort this array on the first key value bij date? So the first element is   Array (     [07-12-2015] => Array         (           ------------         )     [08-12-2015] => Array         (           ------------         )     [09-12-2015] => Array         (           ------------         ) )

I have an array in this format:  Array (     [0] => Array         (             [28th February, 2009] => 'bla'         )      [1] => Array         (             [19th March, 2009] => 'bla'         )      [2] => Array         (             [5th April, 2009] => 'bla'         )      [3] => Array         (             [19th April, 2009] => 'bla'         )      [4] => Array         (             [2nd May, 2009] => 'bla'         )  )    I want to sort them out in the ascending order of the dates (based on the month, day, and year). What's the best way to do that?  Originally the emails are being fetched in the MySQL date format, so its possible for me to get the array in this state:  Array [     ['2008-02-28']='some text',     ['2008-03-06']='some text' ]   Perhaps when its in this format, I can loop through them, remove all the '-' (hyphen) marks so they are left as integars, sort them using array_sort() and loop through them yet again to sort them? Would prefer if there was another way as I'd be doing 3 loops with this per user.  Thanks.  Edit: I could also do this:  $array[$index]=array('human'=>'28 Feb, 2009',                    'db'=>'20080228',                    'description'=>'Some text here');   But using this, would there be any way to sort the array based on the 'db' element alone?  Edit 2: Updated initial var_dump


My first time making Ciabatta...  Any ideas why my ciabatta is lacking air bubbles? It tastes nice and light.   It also didn’t rise as much as I’d expected.   I proofed airtight for 90 minutes then open air on a baking sheet for about 35 minutes.   I did notice the initial mix was really wet. Maybe a tad too much water I’m thinking?  Edit: Recipe - I halved it and followed it exactly.

What causes the texture of bread to be open, ie with lots of large holes, or close, ie a regular, uniform tender crumb with no large holes? How can I achieve either?


I'm attempting to replicate the attached piece of C# code in Python, but unfortunately I know a lot less about Python than I do with the former. The code essentially generates a list of 2 character/digit values e.g. aa, ab, ac, ad, etc. It includes combinations of A-Z, a-z, and 0-9.   I've looked into django.utils.crypto module, but that creates a randomised output, and the output from my C# code gives the exact amount of combinations when run. This is what I tried with Django's module:  get_random_string(length=2,  allowed_chars=u'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789')   Other options I tried do something similar, so I'm  at a bit of a loss. I know the basics of Python, but unfortunately I haven't found enough to be able to replicate my C# code in Python. The C# code:  var alpha =  "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; var q = alpha.Select(x => x.ToString()); int size = 2; for (int i = 0; i < size - 1; i++)     q = q.SelectMany(x => alphabet, (x, y) => x + y);  foreach (var item in q)     Console.WriteLine(item);   Converted into python, the function should generate about 62^2 combinations of the values in 2 digit integers.

I have a list with 15 numbers in, and I need to write some code that produces all 32,768 combinations of those numbers.   I've found  (by Googling) that apparently does what I'm looking for, but I found the code fairly opaque and am wary of using it. Plus I have a feeling there must be a more elegant solution.  The only thing that occurs to me would be to just loop through the decimal integers 1–32768 and convert those to binary, and use the binary representation as a filter to pick out the appropriate numbers.   Does anyone know of a better way? Using map(), maybe?


someone is making many requests to a specific page on my site that has JS on it. Subsequently, it's driving the CPU load to 100+ if I don't restart apache.  What I tried:  - Reduce KeepAlive timeout - Installed mod_evasive (doesn't seem to work due to MaxChildProcesses, basically it's installed and blacklisting IP's but I can still hit refresh 20 times and it wont block anything) - Installed DDOS DEFLATE (usless, CSF is better) - Configured CSF to protect port 80 and ban IPs with more than 50 connections (many false positives still doesn't prevent CPU spike) - Installed limitipconn only to find out it doesn't work at all with apache 2  - Enabled syn cookies and reduced various tcp timeouts  - Optimized the site to make it less prune to DDOS attacks  Nothing really works and they can still crash my server whenever they want.   Any ideas?  Thanks Oliver

This is a  about DoS and DDoS mitigation.   I found a massive traffic spike on a website that I host today; I am getting thousands of connections a second and I see I'm using all 100Mbps of my available bandwidth.  Nobody can access my site because all the requests time out, and I can't even log into the server because SSH times out too!  This has happened a couple times before, and each time it's lasted a couple hours and gone away on its own.  Occasionally, my website has another distinct but related problem: my server's load average (which is usually around .25) rockets up to 20 or more and nobody can access my site just the same as the other case.  It also goes away after a few hours.  Restarting my server doesn't help; what can I do to make my site accessible again, and what is happening?  Relatedly, I found once that for a day or two, every time I started my service, it got a connection from a particular IP address and then crashed.  As soon as I started it up again, this happened again and it crashed again.  How is that similar, and what can I do about it?


There are notable similarities in the classical laws that govern the gravitational force and the electromagnetic force. Considering stationary point masses/charges, both the gravitational force and the Coulomb force follow inverse square laws: $$ F_g=G\frac{m_1 m_2}{r^2} $$ $$ F_C=\frac{1}{4 \pi \epsilon_0 }\frac{q_1 q_2}{r^2} $$ For the Coulomb force, each electrostatic charge has an electric field and it is the interaction of the two electric fields which create a force. This is analogous to the gravitational fields of masses, which also interact to bring about a gravitational force. Magnetism has of course been shown to arise from the laws of electrostatics in a relativistic setting. See the Feynman Lectures on Physics, Volume II, Chapter 13-6:  If magnetism can arise just from the relativistic effects of moving electric charges, then why does gravitational magnetism not arise as a relativistic effect of moving masses? Physicists such as P. M. S. Blackett and Arthur Schuster did indeed propose notions of gravitational magnetism, although these were were not supported by experimental observations. Does the explanation, for why gravity and electromagnetism seemingly lack this commonality, require transcending the classical description of gravity?

We can think that the electric field and the gravitational field operate similarly in the sense that the forms of their governing laws (namely, Coulomb's law and Newton's law respectively) are strikingly similar. The only difference one can point out is that while the electric charges come in two flavors, the gravitational masses come in just one.  Now, I have read that when a charged particle moves, the electric field lines associated with are distorted in a fashion because of the finite time required for the information about the change in the position of the charge to get propagated. And, I have led to the understanding that this is the cause of the existence of the magnetic field (and that if calculus is used it can be proven mathematically).   So (if this is true then) why doesn't the same thing happen to the gravitational field? Why is there nothing like a gravitational magnetic field? Or, is there?  Note  I have changed the language and the tone of the question massively. Although the question was fairly well received, I believe it was really ill-posed. As pointed out by ACuriousMind in the comment, the ''reason''described here behind the existence of the magnetic field is something that cannot be found a good support for. But still, due to the similarity between the equations describing their static behavior of electric and gravitational fields, one can still ask as to whether a boost would create some sort of a gravitational magnetic field if the original frame only had a static gravitational field. As the accepted answer points out, the answer is, roughly, a yes but the Maxwell-type equations for gravity aren't as well-behaved as are the original Maxwell equations of electromagnetism--one should note. In particular, the equations for gravity take the Maxwell-like form in appropriate weak limits only in some appropriately chosen gauges--and aren't Lorentz covariant.


$$\int_{-3}^{-2} \frac{dx}{2x+1}$$  On solving this I'm getting $\log(-3) - \log(-5)$ and isn't negative log not possible?

What is the integral of $\frac{1}{x}$? Do you get $\ln(x)$ or $\ln|x|$? In general, does integrating $f'(x)/f(x)$ give $\ln(f(x))$ or $\ln|f(x)|$? Also, what is the derivative of $|f(x)|$? Is it $f'(x)$ or $|f'(x)|$?


Given a List<T>, which is the preferred way to iterate on Android? Are there any performance differences on a modern day Android device?  for (int i=0; i<list.size(); i++) {     T element = list.get(i);     ... }   or  for (T element : list) {     ... }   Edit: This question is specific to the Android runtime. The other "duplicate" question doesn't address the Android specifics.

What, if any, is the performance difference between the following two loops?  for (Object o: objectArrayList) {     o.DoSomething(); }   and   for (int i=0; i<objectArrayList.size(); i++) {     objectArrayList.get(i).DoSomething(); }


Exercise:  For which $p\in [1,\infty]$ is $L^p([0,1])$ strictly convex?  Solution: For strict convexity we have two equivalent definition:    If $x\neq 0\neq y$ and $\Vert x+y\Vert=\Vert x\Vert+\Vert y\Vert$ then $x=\lambda y$ for some $\lambda$. If $x\neq y$ with $\Vert y\Vert=\Vert x\Vert=1$ then $\Vert\frac{x+y}{2}\Vert<1$   So I found that $L^p([0,1])$ is strictly convex for $p=2$: \begin{equation} \int_0^1(\frac{f(t)+g(t)}{2})^2dt=0.5\int_0^1(f(t)^2+g(t)^2+2f(t)g(t))dt\leq \frac{\Vert f\Vert^2_2+\Vert g\Vert^2_2}{2}<1 \end{equation}  Question: Are there other $p$ for which $L^p([0,1])$ is strictly convex?

Let $x,y \in L_p$   such that  $\|x\|_p=\|y\|_p=1$ , $1< p<\infty$ and $x\neq y.$ Why is $\|x+y\|_p<2$  ?  I'm not sure how to start the proof.. I don't know how to handle integral of $(x+y)^p$ and it seems that using the binomial theorem won't be a great success.


Could anyone help me answer this question? Or point me in the right direction?  Find a unit vector in the direction in which f increases most rapidly at P and find the rate of change of f at p in that direction.  $$f(x,y) = \sqrt{\frac{xy}{x+y}}; \qquad P(1,1)$$

How would I go about answering this question? Would anyone be able to point me in the right direction?     Find a unit vector in the direction in which $f$ increases most rapidly at $P$, and find the rate of change of $f$ at $P$ in that direction:   $$f(x,y) = \sqrt{\frac{xy}{x+y}}$$


Let $m$ and $n$ be positive integers with no common factor. I have to prove that if square root of ${m\over n}$ is rational, then $m$ and $n$ are both perfect squares, that is to say there exist integers $p$ and $q$ such that $m = p^2$ and $n = q^2$.  Can anyone help me with this??

Let $x=\frac{A}{B}$ be a positive rational number in lowers terms (i.e., $A, B\in\mathbb{N}$ and $hcf(A,B)=1$). Prove that $\sqrt{x}$ is rational if and only if $A$ and $B$ are both perfect squares. (Remember that your proof should work for cases like $A=40$, where $A$ is not a perfect square but has a factor that is a perfect square.) I know prime factorization is involved but that's basically it. Proving that $\sqrt{y}$ (for some number y) is rational if and only if $y$ is a perfect square I can do. Applying that that to the fraction mentioned above? Not so much. Any and all help would be appreciated. Thank you.


What is happening when we install a windows application in windows os? I mean how the software files are distributed in OS when we run a .exe file. I actually get this doubt when I installed Visual Studio in my PC.I have selected the installation directory as D drive. But I have found that some of its files are created in C drive where my OS is installed  under Program files. Actually what is the use of those files in the C drive like app data, Program files etc. Is there any website for reference.

I have a SSD as my primary (C:) drive, mainly used for quickly loading games.   It's pretty small (~30 GB) so I want to keep things that don't really need a speed boost off of it. I attempted installing the Visual Studio 2010 Express beta last night, and it claimed to require 2.1 GB of space so I changed the install directory to a secondary, non-SSD drive.  After this, the installer said that it would use 1.8 GB on C: and ~200 MB on the secondary drive.   While this token gesture of moving 1/10 of the app to the place I told it to is cute, I really want to install everything I can to the secondary drive.   Is there any way to install all of Visual Studio 2010 Express to a drive besides C:?


How to clear the history of recent commands in terminal so that I am unable to scroll through them with up and down arrow keys? Closing and reopening the terminal doesn't seem to clear the history. Nor does the reset command

I want to clear all previous commands from the history of my server. I used history -c and it seems all things are cleared but when I ssh to the server, all the commands are still there.  How can I clear them permanently?


In machine learning data set each feature is considered as a random variable. Random variable is a function which maps the outcomes in sample space to a real value. Now I am trying to understand since each feature is a random variable. what would be the sample space of it? I mean what is the domain it is trying to map?

What do they mean when they say "random variable"?


This is the source string:  %5B++The+transmission+is+%5B150mhz%5D+The+year+is+%282017%29+This+is+%2A+great+%2A+so+far++%5D    Is it possible to make a pattern only with GNU SED to:   Replace a singe + to a single space From %**abc to "\x**"abc (the first two characters after the % is always hex UTF-8) Every sentence must have one " at the beginning and one " at end of the sentence    So the result to be like this:  "\x5B"  "The" "transmission" "is" "\x5B"150mhz"\x5D" "The" "year" "is" "\x28"2017"\x29" "This" "is" "\x2A" "great" "\x2A" "so" "far"  "\x5D"   So when echo is used with the string:  echo -e "\x5B"  "The" "transmission" "is" "\x5B"150mhz"\x5D" "The" "year" "is" "\x28"2017"\x29" "This" "is" "\x2A" "great" "\x2A" "so" "far"  "\x5D"   Will result exactly like this:  [ The transmission is [150mhz] The year is (2017) This is * great * so far ]

How can I encode and decode  (URL encoded) strings on the command line?  I'm looking for a solution that can do this:  $ percent-encode "ændrük" %C3%A6ndr%C3%BCk $ percent-decode "%C3%A6ndr%C3%BCk" ændrük


I'm cooking my meat above 55C, mostly around 65C. I understand there are all kinds of safety measures surrounding defrosting. Using cold water and changing it every 30min or defrosting in the fridge. Making sure not to leave it on the counter or not to use warm/hot water. This is because of the danger zone; bacteria doubles every ~20 min. If I am defrosting meat in order to cook it, and I am cooking at safe temperatures, then why should I worry about how I defrost my meat?

If cooking meat kills bacteria, and bacteria are responsible for problems with eating meat which has been left out, then why is it dangerous to eat meat which has been left out at room temperature and then thoroughly cooked?   mentions that "Even if the bacteria is dead, toxins can remain if the food was out too long, causing problems".  However, there's no further detail given.  Are these toxins as dangerous as the bacteria themselves?  How long does meat have to be left out to accumulate a dangerous level of toxins and thus be dangerous even if thoroughly cooked?  Are these toxins the reason for the usual guideline of keeping meat unrefrigerated for a maximum of 2 hours?  update  The revelation, courtesy of Aaronut, that e. coli is actually dangerous because of its toxins — which cannot be denatured at temperatures which will leave meat in an edible state — has pretty much answered this question.  And also given me further incentive to stop eating meat altogether :)  Our discussion (see the comments on hobodave's answer) has progressed into the realm of microbiology.  Some highlights from my ongoing research:  .  These seem to be the reason for the importance of keeping meat at a high temperature for a period of time.  .  This also provides fascinating insight into how bacteria evolved immunity to antibiotics.  Fungi.


The graph of $f$ is $G(f) = \{(x,f(x)) : x\in X\} \subseteq X\times Y$ $X$ and $Y$ are metric spaces. $Y$ is compact. $f$ is continuous iff $G(f)$ is a closed set. I got the closest answer  but I tried it by myself first and got stuck at one point and I need help on that particular situation which I didn't get anywhere else/ $\Rightarrow$ part: Let $(z_n)=(x_n,f(x_n))\in G_f$ be a convergent sequence of $G(f)$. If $(x,y)$ is its limit. We have to show that $y=f(x)$ in other words $(x,y)\in G_f$. $x_n \to x$ $\Rightarrow$ $f(x_n)\to f(x)$[By continuity of $f$.] $\Rightarrow f(x)=y$ by uniqueness of the limit. Hence $G_f$ is closed. $\Leftarrow$ part: Let $x\in X$ and $(x_n)$ a convergent sequence with limit $x$. You have to prove that $(f(x_n))$ is convergent in $Y$ with limit $f(x)$. I have used the sequence $z_n=(x_n,f(x_n))$ and $G_f$ is closed in the compact space $Y$ and hence $G_f$ is compact. Then there is subsequence $(x_{n_k},f(x_{n_k})) \to (x,y)\in G_f$. Then we will have $y=f(x)$ but how do I prove that $f(x_n) \to f(x)$? It is true that every subsequence of $f(x_n)$ has a subsequence converging to $f(x)$.

The graph of $f$ is $G(f) = \{(x,f(x)) : x\in X\} \subseteq X\times Y$  $X$ and $Y$ are metric spaces.  a) Suppose $f$ is continuous and prove that $G(f)$ is a closed set.  b) Suppose that $G(f)$ is compact and prove that $f$ is continous  For a), the definition of a closed set that comes to my mind is a set that contains all its limit points (or was it accumulation points?), is there another equivalent definition that may b more helpful to prove a)? Is it possible to prove this directly? Because at first glance the only way I could imagine to prove this is by contradiction or contrapositive.   I imagine that the proof of b) will be immediately derived from a).


This seems very simple, but I have not been able to come up with an answer to it.  Suppose $a+bi \mid n$ in $\mathbb{Z}[i]$, where $a,b \in \mathbb{Z}$ with $(a,b)=1$. Prove that $a^2 + b^2 \mid n$ in $\mathbb{Z}$.  My attempt was: $a+bi \mid n \implies \overline{a+bi}\mid n$ (otherwise $n$ is not an integer), and if we have that $(a+bi,a-bi)=1$ (or a unit) in $\mathbb{Z}[i]$, then by unique factorization this implies that $(a+bi)(a-bi)\mid n$. However, I found it difficult to prove $(a,b)=1$ in $\mathbb{Z} \implies$ $(a+bi,a-bi)=1$ in $\mathbb{Z}[i]$. Does anyone have a nice solution to this? Any solution is welcome. For additional context, this question came up as I was trying to prove that $\mathbb{Z}[i]/(a-ib) \cong \mathbb{Z}/(a^{2}+b^{2})\mathbb{Z}$ when $a,b$ are coprime in the integers. A way of doing this using natural injections is given in , where there are many very good answers. One way is to use the first isomorphism theorem with the canonical map $\mathbb Z \to \mathbb Z[i]/(a - i b)$, and I need to prove that the kernel of that map is $\langle a^2+b^2 \rangle$. In every answer I saw on this, the solution skips over that step, making me suspect that there's something very simple I'm missing.

I used this isomorphism today but now I'm having trouble justifying it. The norm function isn't additive so I can't come up with a ring isomorphism to prove the following:     For any $\,a+bi\in\Bbb Z[i],\,\gcd(a,b)=1$, we have a ring isomorphism   $$\Bbb Z[i]/\langle a+bi\rangle\,\cong\Bbb Z/(a^2+b^2)\Bbb Z=:\Bbb Z_{a^2+b^2}.$$   Could someone show me an isomorphism between these rings to prove this?


I am editing a document in Texmaker and am fairly new to LaTeX. I am using the output PDFLaTeX/view PDF. I added the kpfonts package to my document to change the font:   \usepackage{kpfonts} \usepackage[T1]{fontenc}   and got the following error:   ! LateX Error: File 'kpfonts.sty' not found.   What does this mean?

I'm trying to compile a document that only works with an up-to-date distribution, so I'd like to know: how do I update my distribution? Please provide screenshots where appropriate.  List of answers           To keep an eye on what’s going on at CTAN you may subscribe to the  or the RSS feed feed://www.mail-archive.com/ctan-ann@dante.de/maillist.xml


I have a copy of Excel 2007 that happens to be in Brazilian Portuguese. For me it's great since I'm in Brazil but there is a catch.  All the English shortcuts I'm used to, like Ctrl+S for saving, Ctrl-B for bold etc. are also translated.  When I press Ctrl-S it thinks I want to underline the text.  How do I change the shortcuts to the English default?

My office is not in English, so to save the document the shortcut is Ctrl B.  For me this should be bold, how can I change the mappings to the same as the English version? Is there a file I can replace to have all the shortcuts mapped?  I want to download a template, and not edit 1 by 1.


Can anyone help with this one please  I need a regex pattern to check the first 2 numbers match either 01 or 02 or 03 or 07 only

I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?


For some reason, there appears to be a cut-off point on my stage beyond which nothing renders. I run into it when I'm rotating the camera around my objects (I keep the "camera fixed to view" option on so I don't get lost so easily).    It's as if there was a curtain or something there, impeding the view, but I can find no obvious reason for it.  Any ideas?

I have created a simple model here   When rendering it the end of it is cut off   How can I get the camera to render a longer distance?


I'm trying to simulate the history of a shell like script. The first step (at least from what I think) is to make it recognise the up or down arrows. Let me show you the code first:  string readSequence() {     int c;     string currLine;     do {        if (getchar() == '\033') { // if the first value is esc             getchar(); // skip the [             c = getchar(); // get the real value                 if(c == 'A') // the real value                     cout << "up";                 if(c == 'B')                     cout << "down";         }     } while(c != EOF || c != '\n'); }   Whenever I run this in the command line, if I press up down up down for instance, it will print ^[[A^[[B^[[A^[[B, and after I press enter it will print updownupdown. I'm trying to make it print up or down as soon as the user presses up or down, and also make it not to print those ^[[A or ^[[B things.  Also, if you got any suggestions on how to do this in another way, please do share. Thanks in advance!

I can never remember how I do this because it comes up so infrequently for me. But in C or C++, what is the best way to read a character from standard input without waiting for a newline (press enter).  Also ideally it wouldn't echo the input character to the screen. I just want to capture keystrokes with out effecting the console screen.


Question: Find all functions $f:\mathbb{N}\rightarrow\mathbb{N}$ such that $yf(x)+xf(y)=(x+y)f(x^2+y^2)$ for positive integers $x, y$.  My attempt at a proof is the following:  (1) As well if $x=y$ we have $$2xf(x)=2xf(2x^2)\Rightarrow f(x)=f(2x^2)$$ (2) Now observe if $f(x)=f(y)$ we have wlog $$(x+y)f(x)=(x+y)f(x^2+y^2)\Rightarrow f(x)=f(x^2+y^2)$$ That's all I've got for now, and I'm out of ideas.  Edit: I forgot to add I'm relatively certain the only function which works is the constant function as playing around with pythagorean triples yields a lot of cases where $f(1)=f(x)$  Edit: Removed lemmas made under the incorrect assumption that 0 is included in $\mathbb{N}$ this case.

The question below is from the 2002 Canada National Olympiad. I have found one family of functions but need help in finding (or proving the non-existence) of others. Suggestions on how to improve the solution method (especially rigour of arguments) would also be appreciated.     Let $\mathbb{N} = {0,1,2,\dots}$. Determine all functions $f : \mathbb{N} \rightarrow \mathbb{N}$ such that       $xf(y) + yf(x) = (x + y)f(x^2 + y^2) \tag{1}$      for all $x,y \in \mathbb{N}$.     Expressing $f$ as a power series:  $f(t) = a_0 + \displaystyle{\sum\limits_{k=1}^{\infty}{a_k x^k}} \tag{2}$  Assuming the power series is convergent, the general coefficient, $a_n$, is the same on both sides of equation (1). [I am not sure of this step].  So for $a_0$  $x(a_0) + y(a_0)=(x+y)(a_0)$  which is satisfied for all values of $a_0$. Hence $\boxed{f(t)=a_0,\:a_0\in\mathbb{N}}$ is a solution.  For any $n > 0$, we have  $\begin{align} x a_n y^n + y a_n x^n &= (x+y)a_n(x^2+y^2)^n \iff \\  a_n(xy^n+yx^n) &= a_n(x+y)(x^2+y^2)^n \end{align}$  and if this is true for fixed $n>0$ and all $x,y\ge0$ then $a_n=0$. So I am unable to find any other functions.


I am editing the question that i added yesterday because i solved that issue. Now i want to know that, is there any specific way to push the data into database?  I am using sqlite database ( firefox plugin ) and eclipse for coding.   Thank you

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?


As has been noted in many instances Sauron was searching for the  and it has been subtly suggested that the ring itself was trying to get back to Sauron. That's why it deserted Gollum after all those centuries. It is also know that Sauron invested vast amounts of his power in the Ring.   So why was he unable to detect it unless someone was wearing it?     Saruman discovers that Sauron's servants are searching the Anduin near Gladden Fields, and that Sauron therefore has learned of Isildur's end. He is alarmed, but says nothing to the Council.   The Return of the King, LoTR Appendix B, The Tale of Years: The Third Age   Also:     Sauron intended it to be the most powerful of all Rings, able to rule and control those who wore the others. Since the other Rings were themselves powerful, Sauron was obliged to place much of his own power into the One to achieve his purpose.   The Silmarillion, "Of the Rings of Power and the Third Age", p. 287–288

When Frodo put on the One Ring, both the Nazgul and Sauron himself found Frodo. However when Bilbo had the ring and possibly used it many times, Sauron sought Gollum to get a hint on where to look for the ring and send the Nazgul after it.   Sauron sought Gollum before Bilbo wore the ring at his birthday party, slightly after that time, he was very effective at locating Frodo when Frodo put on the ring. So I guess it's not a matter of Sauron gaining any extra powers with time.  Also Bilbo seemed to use the ring without it bothering him at any point, unlike Frodo who seemed to be very troubled when using the ring. How is that possible?


I want to install an instance of Windows Server 2012 R2 OEM as a virtual machine on our VM server.  Does the OEM version require me to download a different OS image that so we can install and use the OS?

This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y?


I am attempting to obtain a token, using the Oauth 2 refresh token flow.    I am using the REST Console in Chrome to perform the following POST operation:  My URI is   My Content-Type header is "application/json"  I am posting the following body (client id and secret omitted)  { "client_id":"<supersecret>" ,"grant_type":"authorization_code" ,"client_secret":"<supersecret>" ,"redirect_uri": "https://" }   From what I gather from the saleforce oauth2 refresh token flow documentation, this should work.  However, I am getting the following error for a response:  {     "error_description": "grant type not supported",     "error": "unsupported_grant_type" }   Any thoughts on why the service doesn't like my grant_type parameter?

I'm building a small application in Go that will access Salesforce using REST. I chose to use the full OAuth webflow.   Documentation for the   I'm able to do the full flow when I use urlencoded form data in the token request (number 3 in the flow chart in the documentation).   func httpPostXCoded(c appengine.Context, theUrl string, attrs map[string]string, OAS OAuthSecurity) (body []byte, err error) {     var myUrlEncoded = ""     for key, val := range(attrs) {         if len(myUrlEncoded) > 0 {             myUrlEncoded += "&"         }         myUrlEncoded += key + "=" + url.QueryEscape(val)     }     req, err := httpRequest("POST", theUrl, bytes.NewReader([]byte(myUrlEncoded)))     if err != nil {         return     }     req.Header.Add("Content-Type", "application/x-www-form-urlencoded")     res, err := httpClient(c).Do(req)      // cut code }   I would however like to use a JSON-formatted request - I changed the code to look like this  func httpPostXCoded(c appengine.Context, theUrl string, attrs map[string]string, OAS OAuthSecurity) (body []byte, err error) {     var rbody []byte     var req *http.Request     if rbody, err = json.Marshal(attrs); err != nil {         return     }     req, err = httpRequest("POST", theUrl, bytes.NewReader(rbody))     if err != nil {         return     }     req.Header.Add("Content-Type", "application/json")     res, err := httpClient(c).Do(req)      // cut code }   Salesforce won't send me a token but an error message like this  {"error_description":"grant type not supported","error":"unsupported_grant_type"}   As you can see in the code snippet above I am setting the Content-Type to json. In both cases I have a key in the map called "format" with the value "json". The working urlencoded request will, correctly, give me json formatted data back.   An example of the json data I'm sending is   {"client_id":"","client_secret":"","code":"","format":"json","grant_type":"authorization_code","redirect_uri":"http://localhost:8080/callback"}   Please note some field has intentionally been emptied.


I got some error from Struts based project in my Eclipse  java.lang.NoClassDefFoundError: org/bouncycastle/asn1/ASN1OctetString    What kind of error is this can any one explain it?

I am getting a NoClassDefFoundError when I run my Java application.  What is typically the cause of this?


I tried to install Android's ROM and got ERROR 7, then I wiped out cache, data, internal storage, where was twrp.apk installed. After that I cant get into boot menu (with Install, Wipe... buttons). Then I copied twrp to the phone: sudo fastboot flash recovery <twrp.img> Tried versions 3.2.1-0 and 3.4.0-0, because I heard for certain phone (I have Xiaomi Mi4) it's necessary to use proper version, though I don't know which. What's going on now: I can successfully can get to the nice splash screen using Volume Down + Power, then on my PC I give sudo fastboot reboot command and press Volume Up + Power and here is the problem: It has no effect, it just keeps rebooting (I see only Xiaomi's logo).


So I am trying to make a jagged array just like in other languages like C#, Java. I tried using this code array = [[0] * 5] * 5 print(list(array))  Which gave this output [[0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]  Which is great!  But the issue is when I try to modify a value in this array, all the arrays get modified. Here is the code: array = [[0] * 5] * 5 array[2][3] = 5 print(list(array))  And this is the output [[0, 0, 0, 5, 0], [0, 0, 0, 5, 0], [0, 0, 0, 5, 0], [0, 0, 0, 5, 0], [0, 0, 0, 5, 0]]  What I was hoping for is something similar to this [[0, 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 5, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]  Any idea why this value assignment is happening to all the arrays?

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


2 hours ago I thought I had this figured out, but now I am doubting myself and want someone to validate my algorithm.   I want to take a stream of k trusted random bits and convert it to groups of 5 digits in a uniformly distributed range from 0-99999. To do this I take k and truncate to a multiple of 32, let's say the result now has n bits where n = k - k % (4*8). To create one group of 5 digits we load 32 bits into a variable we'll call var_i. The result will be stored in var_e. To get 5 digits from 0-99999 takes 17 bits, so we perform the loop:      for (int i = 0; i < 17; i++)       var_e += ((var_i >> i) % 2) << i   this way we preserve only the first 17 bits. Then we perform var_e = var_e % 100000 to truncate var_e to 5 digits. var_e is now one complete block of 5 digits.  An alternative algorithm could be to just take a 32 bit number var_e and perform var_i = var_e % 100000. This would take just the last 5 digits of the 32 bit number, which fall into the range 0-99999.  These algorithms both waste nearly 50% of the input data, but it would be fairly easy to change the first one to accept 17 bits of input.

Say that we have a secure random number generation that outputs 32 bit random numbers, so it's output is a true random number between 0 and a MAX.  What is the best way to map this random number to a defined range (say I want something random between X and Y) without loosing too much entropy?


I'm trying to count the lines from a command and I'd also like to see the lines as they go by.  My initial thought was to use the tee command:  complicated_command | tee - | wc -l   But that simply doubles the line count using GNU tee or copies output to a file named - on Solaris.

I want to execute a command, have the output of that command get gzip'd on the fly, and also echo/tee out the output of that command. i.e., something like: echo "hey hey, we're the monkees" | gzip --stdout > my_log.gz  Except when the line executes, I want to see this on standard out: hey hey, we're the monkees


I want to know what's the procedure to become a state level Cricket Umpire?   please explain starting from the grass root Steps.

In cricket how does someone become an umpire at international level? Is there some procedure for this? How are they selected and what is the criteria for this?


So I have two objects... a UV sphere and a rope that I modeled. All I want to do is have two different cloth physics (one for sphere, one for rope) and basically attach the sphere to the rope. The whole idea is to have the sphere raising up and dragging the rope with it. Could someone kindly explain how I attach two objects with two different cloth physics please? I'm struggling a bit. Thank you!

I'm trying to simulate balloons gathering under a tent. I've finally figured out the stiffness and gravity of the balloon using a combo of soft body and rigid body modifiers, but the string is now the only issue.   (View from bottom looking up)   The string just continues to gather at the top instead of hang down. How do I make the balloon have negative gravity, and the string have positive gravity? Or.. is there another solution for it to remain hanging down?  The eventual goal is to add maybe 50 balloons to the scene to have them fill the tent with their strings hanging down.


How can I reference a variable in bash based on another variable? Let me setup the example:  package="foobar"  # the variable I wish to reference is $foobar_darwin_amd64 # thus trying: echo "$package_darwin_amd64"   But this does not work.

I am trying to print a simple value for $AR1_p1 but the variable $i is not evaluating. for i in 1 2 3 4 do     AR1_p1=22     AR1_p2=23     AR1_p3=24     AR1_p3=25     echo $AR1_p$i done   It's like concatenating dynamically. Any suggestions on how to fix this?.


I'm making a 2d RPG and I'm having trouble designing a sprite, so I downloaded an image of Pokémon Leaf Green's player sprite and copied how it looked. I didn't copy it completely, only how it looks. Here's the image:    Can I get sued for this? the gameplay and mechanics are far from Pokémon's mechanics, the only problem is the sprite of the characters. Can I get into trouble because the character sprite looks too much like Pokémon's character?

Most games build on other games' successes and many are downright clones. Where is the limit of imitation before legal issues come into play? Is it down to literary or graphic work like characters and storyline that cause legal problems, or can someone actually claim to own gameplay mechanics?  There are so many similar clone games out there that the rules are probably very slack or nonexistent, but I'd like to hear the views of more experienced developers / designers.


I have a plan to upgrade my 2008R2 Standard Edition to 2012R2 Standard Edition, and then virtualize them with Hyper-V 2012R2. Is it possible to upgrade from Windows Server 2008R2 Standard Edition to Windows Server 2012R2 Standard edition if I have SA (software insurance)? What would be my next steps for legal OS licensing for this environment? Can I use these licenses for virualizing environment (Hyper-V server)?  I have seen that with SA you can migrate from 2008R2 Standard to 2012R2 standard, but I couldn't figure out can I transfer these licenses to new server? I read a lot about licensing rights, but I couldn't find the exact situation that would be of use for me.

This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y?


Please suggest a Linear Algebra book with an introduction and rigorous theory (description) on Eigenvectors , eigen-values , Cayley-Hamilton theorem , Diagonalisation of matrices ; Quadratic forms ( Sylvester's Law , rank , signature , reduction to canonical forms ) .   Thanks in advance

I plan to self-study linear algebra this summer. I am sorta already familiar with vectors, vector spaces and subspaces and I am really interested in everything about matrices (diagonalization, ...), linear maps and their matrix representation and eigenvectors and eigenvalues. I am looking for a book that handles every of the aforementioned topics in details. I also want to build a solid basis of the mathematical way of thinking to get ready to an exciting abstract algebra next semester, so my main aim is to work on proofs for somehow hard problems. I got Lang's "Intro. to Linear Algebra" and it is too easy, superficial.  Can you advise me a good book for all of the above? Please take into consideration that it is for self-study, so that it' gotta work on its own. Thanks.


I want to limit my Google search query to a set of websites. I am using the Opera Mini browser on my tablet for searching.

Is there any way to send a search query to several websites at once and browse results?  For example, I want to buy edible paper. Paper on which you can write and take a bite off for a nutritious snack. I've found about 15 websites that sell this type of paper and have a search field.  Is there any way to search all of those 15 websites at once with one single search query and view results individually later instead of going to each website manually, entering the search term 15 times?


I'm new in Ubuntu, I want to install windows 10 on my Lenovo Thinkstation, Ubuntu 16.04 is already installed but I want to install windows 10. When I try for windows installation through USB, window can't find any hard drive for installation.  How I can install windows? I don't need Ubuntu

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


I can't update, i have this error when running apt-get update command!  W: Failed to fetch http://ppa.launchpad.net/cooperjona/nitrotasks/ubuntu/dists/utopic/main/binary-amd64/Packages  404  Not Found  W: Failed to fetch http://ppa.launchpad.net/cooperjona/nitrotasks/ubuntu/dists/utopic/main/binary-i386/Packages  404  Not Found  E: Some index files failed to download. They have been ignored, or old ones used instead.   what can i do?

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?


From  I've taken this advice:     You should accept a post (Looks good)   ...   • [ANS] Note that answers that are clear and address the question at least a little, but are fundamentally wrong, should be downvoted, not deleted. A wrong answer still “looks good”.   Makes sense to me, but "Looks Good" is misleadingly worded. I suspect many people, especially those that haven't read mentioned guidelines, will be confused and may refrain from picking that option (perhaps choosing one of the "delete" options).  Question: can we do something about this?  Perhaps rewording "Looks Good" to something else (suggestions welcome), or the option to downvote an answer and have an "I'm done" button?

When reviewing possibly low quality posts you sometimes see OK answers, except that they're wrong. From the review interface you can't downvote so you can only comment or edit, and editing isn't really an option when the intended answer is wrong.  Once you've commented or upped an existing comment, should we then click Looks Good because there's nothing wrong with the answer, except that it's wrong, or Not Sure so that the answer is reviewed again (and again)?


Using a multimeter and set it on 200V DC - that's the lowest on this meter. Tested a 1.5V and it reads 2.8 Tested a 3V and it reads 6. Just replaced the battery. The meter is ETEKCITY. Any suggestions?

When measuring the AC voltage across a DC battery (CR2032), and I am getting 6v. The DC voltage across it is 3.01 volts. I also tested on a 9 volt battery; again the same thing. I am reading about 20 v AC and 10v DC. I am using MASTECH MAS830L multi meter. I also used another multimeter, and I get the same result.  When I am putting the multimeter probes in the same polarity with the battery, I am getting the AC voltage, but none if I put the probes in reverse polarity.  Why is this happening?


If negative mass is rotating around fixed positive mass, then what will be the nature of force and how?

Or does it exist mathematically?  Is it really inconsistent with a common-sense, mathematics or known physical laws?   As far as I understand, if it exists, it must be far away from the "positive" matter because of repelling force, so it explains why there is no observations of such matter.   It would be also very consistent with the idea that the total energy of the Universe is zero. Doesn't it imply that the total mass of  the Universe is zero?   Can you please clarify the statements below that seem to contradict each other?  1)  -Max Tegmark.  2) Despite being completely inconsistent with a common-sense approach and the expected behavior of "normal" matter, negative mass is completely mathematically consistent and   3) Such matter would  and show some strange properties, stemming from the ambiguity as to whether attraction should refer to force or the oppositely oriented acceleration for negative mass.