What do you understand by this line "dr-- -w- --x file"
What do the fields in ls -al output mean?
Clipping image with Basic (ArcView) level license of ArcGIS Desktop? Is there a way to trim a geo-referenced air photo to an irregularly shaped boundary?    I tried the clip tool shown in my attachment, but it didn't work.  It looks as though the output extent field requires a rectangularly shaped polygon as the clipping feature.    Can I even do this in ArcView?    I've never had a request to do anything like this before.        I do use Photoshop and other similar software packages.  I could just go in to an environment like this &amp; start painting everything outside of my boundary in white, but then I would have to come back in and geo-reference the image again, and it just strikes me that there must be a faster and easier way (even though I only have ArcView 9.3). @track vs @api (Lightning Web Components) Let's say we have this code for a LWC:  &lt;!-- helloExpressions.html --&gt; &lt;template&gt;     &lt;div class="slds-m-around_medium"&gt;         &lt;lightning-input name='firstName' label="First Name" onchange={handleChange}&gt;&lt;/lightning-input&gt;         &lt;lightning-input name='lastName' label="Last Name" onchange={handleChange}&gt;&lt;/lightning-input&gt;         &lt;p class="slds-m-top_medium"&gt;Uppercased Full Name: {uppercasedFullName}&lt;/p&gt;     &lt;/div&gt; &lt;/template&gt;   and this is the JS file:  // helloExpressions.js import { LightningElement, track } from 'lwc';  export default class HelloExpressions extends LightningElement {     @track firstName = '';     @track lastName = '';      handleChange(event) {         const field = event.target.name;         if (field === 'firstName') {             this.firstName = event.target.value;         } else if (field === 'lastName') {             this.lastName = event.target.value;         }     }      get uppercasedFullName() {         return `${this.firstName} ${this.lastName}`.toUpperCase();     } }   firstName and lastName have been decorated with @track. Now as per the documentation, decorating a property with @track makes it private and reactive, while to mark a property public and reactive, use @api.  So if I just change the decorator to @api for both these variables, it should work. I am referring these from the same component only. But it's not working.  UPDATE: 27th Feb -------------------- Somehow it's working today. I just changed the decorator of the variables to api.  import { LightningElement, api } from 'lwc';  export default class HelloExpressions extends LightningElement {     @api firstName = '';     @api lastName = '';      handleChange(event) {         const field = event.target.name;         if (field === 'firstName') {             this.firstName = event.target.value;         } else if (field === 'lastName') {             this.lastName = event.target.value;         }     }      get uppercasedFullName() {         return `${this.firstName} ${this.lastName}`.toUpperCase();     } }   So it's working. Electrical potential energy stored in vacumm for a single point charge? I have come to know the electrostatic potential energy in vacuum is given by $${\frac{1}{2}} \epsilon_0\int d^3x {E^2} $$ and this energy  is due to the mutual electrostatic coulomb potential energy. So only a single point charge in space also contributes to some electrostatic potential energy according to $${\frac{1}{2}} \epsilon_0 \int d^3x {E^2} $$  as due to a single point charge also we have an electric field at every point in space. Now I am not getting it physically, why should there be any Coulomb energy in this case as there is no other charge to provide the electrostatic coulomb potential energy? Does ReLU layer work well for a shallow network? How can I connect two different DC power sources together? How can I connecting two different DC power sources together? for example 15Vdc(5Amp) with 5Vdc(2Amp). I want to make one DC source (20Vdc,7Amp) by more powerful supplies. Handling very large numbers in Python How can I remove launcher drive icons? List sections of chapter at beginning of that chapter How can one have a mini table of contents for the current chapter appear just after the chapter name listing all sections of that chapter? I think my MacBook Pro battery was replaced by Apple's service team. How do I check that? What do the supercharges in extended supersymmetry do? What do the supercharges in  do?  In ${\cal N}=1$ supersymmetry there are a certain number of fermions and and equal number of bosons. You can transform all fermions to the bosons (and vice versa) in a 1 to 1 fashion using a single supercharge, $Q$.  So what happens when you have, for example, ${\cal N}=2$ supersymmetry with 8 supercharges? Since $Q$ is a generator of supersymmetry transformations, is it a linear combination of these supercharges that act on the particles? In which case could one particle be acted on by two separate linear combinations of $Q$? Or is it strictly one linear combination of $Q$ per fermion/boson?  Also, what does ${\cal N}$ mean physically? What difference does ${\cal N}=2$ have to ${\cal N}=1$ other than more supercharges? Or is that the only difference between the two theories? SEO and buying expiring or dropped domain Does it make any difference for SEO benefits to buy dropped and already available domains other than backorder domains that are expiring soon?  I heard somewhere that whois gets deleted after being dropped. But I didn't find any confirmation if it's true or not.  Anybody can tell me if there are benefits of one against the other, if yes what? 12.04.3 can start only after I press "resume" in rescue mode (every boot) - problem with Nvidia driver I've tried to install maybe ten Linux distros on my new PC, and every time I have problems with video drivers: black screen or visual artefacts.  I was able to install only Ubuntu 12.04.3 64-bit, but also with problems: black screen on startup (sometimes all was normal when I used Live mode before install, sometimes I was not able to load Live Mode - Ubuntu says that I have problems with video and gives me a choice with four elements, one of them "use safe graphics mode", but I even can't choose this - the system is frozen).   In tty I installed nvidia-current, but it didn't help me. Every boot I need to press ESC and enter rescue mode and just press Resume and after this the system boots normally. If I try to do a normal restart I get a black screen after Ubuntu logo again.  I tried switching nvidia driver in the options - I have version 319-updates and version 319 [Recommended], but neither works.  I have Palit GeForce GTX650, all updates. Using the properties of real numbers, verify commutativity on complex numbers. I have just started self-studying Linear Algebra after a 3 year hiatus from mathematics (in an extended neuroscience foray), and I want to ensure that I am sufficiently verifying commutativity of complex numbers by using the properties of real numbers.  My attempts...  (1) Commutativity of Addition:   Verify that $w + z = z + w$ for all $w, z \in \mathbb{C}$.  $$w + z = (a + bi) + (c + di) \hspace{10mm}\text{by definition of }\mathbb{C}$$ $$\hspace{13mm} = a + (bi + c) + di \hspace{10mm}\text{by associativity in }\mathbb{R}$$ $$\hspace{17mm} = a + (c + bi) + di \hspace{10mm}\text{by commutativity in }\mathbb{R}$$ $$\hspace{16mm} = (a + c) + (bi + di) \hspace{10mm}\text{by associativity in }\mathbb{R}$$ $$\hspace{19mm} = (c + a) + (di + bi) \hspace{10mm}\text{by commutativity in }\mathbb{R}$$ $$\hspace{13mm} = c + (a + di) + bi \hspace{10mm}\text{by associativity in }\mathbb{R}$$ $$\hspace{17mm} = c + (di + a) + bi \hspace{10mm}\text{by commutativity in }\mathbb{R}$$ $$\hspace{17mm} = (c + di) + (a + bi) \hspace{11mm}\text{by associativity in }\mathbb{R}$$ $$\hspace{13mm} = z + w \hspace{34mm}\text{by definition of }\mathbb{C}$$  $$\blacksquare$$  This seems a bit verbose to me - is it acceptable to combine steps? For example, rather than:  $$w + z = (a + bi) + (c + di) \hspace{10mm}\text{by definition of }\mathbb{C}$$ $$\hspace{13mm} = a + (bi + c) + di \hspace{10mm}\text{by associativity in }\mathbb{R}$$ $$\hspace{17mm} = a + (c + bi) + di \hspace{10mm}\text{by commutativity in }\mathbb{R}$$ can I instead write: $$w + z = (a + bi) + (c + di) \hspace{10mm}\text{by definition of }\mathbb{C}$$ $$\hspace{48mm} = a + (c + bi) + di \hspace{10mm}\text{by associativity and commutativity in }\mathbb{R}$$?  (2) Commutativity of Multiplication:  Verify that $wz = zw$ for all $w, z \in \mathbb{C}$.  $$\hspace{-14mm}wz = (a + bi)(c + di) \hspace{24mm}\text{by definition of }\mathbb{C}$$ $$\hspace{4mm} = a \cdot c + a \cdot di + bi \cdot c + bi \cdot di \hspace{10mm}\text{by distribution in }\mathbb{R}$$ $$\hspace{9mm} = a \cdot c + bi \cdot c + a \cdot di + bi \cdot di \hspace{10mm}\text{by commutativity in }\mathbb{R}$$ $$\hspace{35mm} = c \cdot a + c \cdot bi + di \cdot a + di \cdot bi \hspace{10mm}\text{by multiplicative commutativity in }\mathbb{R}$$ $$\hspace{1mm} = c(a + bi) + di(a + bi) \hspace{20mm}\text{by distribution in }\mathbb{R}$$ $$\hspace{5mm} = (c + di)(a + bi)\hspace{34mm}\text{by distribution in }\mathbb{R}$$ $$\hspace{4mm} = zw \hspace{55mm}\text{by distribution in }\mathbb{R}$$ $$\blacksquare$$  This also seems a bit wonky to me. Any and all suggestions on clearing up my verification, reasoning, etc. would be greatly appreciated! How do I write a correct micro-benchmark in Java? How do you write (and run) a correct micro-benchmark in Java?  I'm looking for some code samples and comments illustrating various things to think about.  Example: Should the benchmark measure time/iteration or iterations/time, and why?  Related: I have a button created by my script. I wonder how I can display what the system console displays but inside blender's console. CoDEmanX did this by running a script inside it as shown , but I want to display what happens in the system console inside blender's console.  My .blend file can be found here: It is my understanding that metals are a crystal lattice of ions, held together by delocalized electrons, which move freely through the lattice (and conduct electricity, heat, etc.).   If two pieces of the same metal are touched together, why don't they bond?   It seems to me the delocalized electrons would move from one metal to the other, and extend the bond, holding the two pieces together. If the electrons don't move freely from one piece to the other, why would this not happen when a current is applied (through the two pieces)? Identifying genes from a list of genes I have a gene list file. Some thing like this      SWT21     SSA1     NRP1     EFB1     TFC3     MDM10   I have another file which also contains the names of these genes in my list along with other essential information about them. The second file looks like this:  chrI    147593  151166  YAL001C -   TFC3 chrI    143706  147531  YAL002W +   VPS8 chrI    142173  143160  YAL003W +   EFB1 chrI    140759  141407  YAL004W +   YAL004W chrI    139502  141431  YAL005C -   SSA1 chrI    137697  138345  YAL007C -   ERP2 chrI    136913  137510  YAL008W +   FUN14 chrI    135853  136633  YAL009W +   SPO7 chrI    134183  135665  YAL010C -   MDM10   I want to extract those lines in the 2nd file which have gene names as are present in first file. How to submit webform programmaticaly? With $x+y\ge z$ $(x,y,z\ge0)$, prove that: $$\frac{x}{1+x}+\frac{y}{1+y}\ge\frac{z}{1+z}$$  I'm aware that using analytic view this is easy since $f(x)=\frac{x}{1+x}$ is concave in $[0,\infty)$. However I want to prove it using merely algebraic techniques. Is that possible? Constraint the camera to look at an object In my scene I have a camera sitting at the origin. I would like to contraint it so that it always looks at the center of a given object. But the camera should not change its position.  I found some answers using a "TrackTo" or "LockedTrack" constraint but could not manage to make it work.  Could I probably use a Driver for this and if yes, how can I adjust it?  Thanks in advance!