Finding the radical of $\mathfrak{gl}(2,\mathbb{C})$
Radical of $\mathfrak{gl}_n$
555 Monostable Timer delay I have built numerous 555 circuits over the years. I recently had to built a Monostable 555 cct. as per this site :    The cct. is used in a motor vehicle. When the remote control is pushed to open the doors, it sends positive 12V to this Monostable cct. to initiate it and a 3 Amp Power Transistor pulses the siren momentarily to indicatse "unlocking" by audible means.   The issue I have is that Rt and Ct used to time the output pulse is not short enough. I replaced these components to the smallest values I could get, but the output is still "too long". Teh siren makes a "chooow" sound instead of "chow". Sounmds too unprofessional or after-market.  Any ideas to get a short pulse (nearly a few micro seconds) out of this old 555 cct. ? Why was mixing declarations and code forbidden up until C99? What is the tolerable magnetic field (in Tesla) for a hard disk? I was wondering what would be the safest magnetic field for a hard drive so that the data inside it is safe and not wiped off?  For example I have a 2.1 home theatre system and when I take my android phone near it to check the magnetic field range it gives me a reading of 1000 micro Tesla. Would that be considered safe for a nearby hard disk? Select all contents of textbox when it receives focus (Vanilla JS or jQuery) What is a Vanilla JS or jQuery solution that will select all of the contents of a textbox when the textbox receives focus? What does Pokémon Appraisal actually tell you in Pokémon Go? Can you overload controller methods in ASP.NET MVC? I'm curious to see if you can overload controller methods in ASP.NET MVC.  Whenever I try, I get the error below.  The two methods accept different arguments.  Is this something that cannot be done?     The current request for action 'MyMethod' on controller type 'MyController' is ambiguous between the following action methods: See YouTube videos in Anaglyph mode How to see a YouTube video in  from a non-3D Android device? I am not able to enable Anaglyph mode from the YouTube application. Alignment numbered apalike bibliography style I prefer the apalike bibliography style with the number in brackets in front (see also  and ). However what I am curious about is how to align the first and subsequent text lines neatly next to the number in brackets.    Does anyone know how to do this? Is it possible to search every field of every table for a particular value in Oracle?  There are hundreds of tables with thousands of rows in some tables so I know this could take a very long time to query. But the only thing I know is that a value for the field I would like to query against is 1/22/2008P09RR8. &lt;  I've tried using this statement below to find an appropriate column based on what I think it should be named but it returned no results.  SELECT * from dba_objects  WHERE object_name like '%DTN%'   There is absolutely no documentation on this database and I have no idea where this field is being pulled from.  Any thoughts? I was reading through some of the questions and answers here on the Rings of Power and I just wondered why the ring effects, affected different races in a slightly different way.  I know other questions ask and answer some of these things, but I just wondered why the Rings of Power caused greed in Dwarves for ever more amounts of treasure.  It's true that Dwarves loved mining and loved wealth and were built of sturdier stuff than men, but why did the Rings of Power not control Dwarves in the way the other Rings of Power controlled men and why did it produce greed and not invisibility? How to change folders color? How do i change the folders colors? i am using this icon theme   and there are several folders. like black, gray, purple, orange(which is the default), yellow, green, red, blue, brown and lightblue  How can i use any of them? for example have a blue folder called "family" in images and another right beside that have a purple folder called "others".  Basically why have he created all those folders with different colors? This is a basic question on Box-Jenkins MA models. As I understand, an MA model is basically a linear regression of time-series values $Y$ against previous error terms $e_t,..., e_{t-n}$. That is, the observation $Y$ is first regressed against its previous values $Y_{t-1}, ..., Y_{t-n}$ and then one or more $Y - \hat{Y}$ values are used as the error terms for the MA model.  But how are the error terms calculated in an ARIMA(0, 0, 2) model? If the MA model is used without an autoregressive part and thus no estimated value, how can I possibly have an error term? Is it possible to set the default size of the Empty Object? The problem is since I switched my blender scale to metric, the Empty's default size is kinda large for most times I need it. LaTeX: optional arguments with square brackets LaTeX is trying to add a missing $ that I don't want to the following code. Minimal working example:  \documentclass[letter,12pt]{article}  \newcommand{\monkeyBeans}[2][]{   \parbox{4in}{#1} }  \begin{document}  \parbox{4in}{$[a, b]$}   \monkeyBeans[$[a, b]$]{yo monkey}  \end{document}   If I try any of the following lines in my document instead of the call to monkeyBeans, there is no error:  \parbox{4in}{$[a, b]$}  \monkeyBeans[yo monkey]{$[a, b]$} \monkeyBeans[$(a, b)$]{yo monkey} \monkeyBeans{$[a, b]$}{yo monkey}   What is the deal with square brackets in optional arguments? Eccentricity of an ellipse How is $\frac{PF}{PD} = e = \frac{C}{A}$ ? where e is eccentricity, P stands for any point on the ellipse. $F$ stands for one of the foci. $e$ stands for eccentricity. $D$ is a point on the directrix of the ellipse. 'C' is the distance from the center to the focus of the ellipse 'A' is the distance from the center to a vertex.   This is referring to an ellipse/hyperbola/parabola and their conic sections. The problem is not the proof for how $PF/PD = e$, or how $C/A = e$, but how the two equate to each other. (The letters stem from the points/foci of an ellipse of a cone and its directrix).  What is the answer that does NOT use analytic geometry? (only trigonometry) Redirect stdout over ssh I would like to run  something &gt; file   on a remote system through ssh, but if I run  ssh host something &gt; file   the redirection is executed locally as ssh etc &gt; file  I've tried it with ' or '' or dd or with a pipe | instead, but I can't get it to work. How can this be done? I am trying to burn a shapefile to a raster using GDAL's RasterizeLayer. I pre-create an area of interest raster from a different shapefile, given a specific pixel size. This AOI then serves as a base for all following rasterizations (same number of collumns and rows, same projection and geotransform).  The issue occurs, however, when I go to burn the shapes to their own raster, based on the same pixel size and projections. The link below (don't have enough rep to post the image), shows the original shapefile in tan, and the dark pink where RasterizeLayer has burned data. The light pink is nodata values for the dark pink raster data. The grey is the AOI based on which the shapefile burn was completed.  Given the extents of the shapefile polygons, I would expect to see burn values in the bottom two corners, as well as the two pixels underneath the data that does show. Obviously, however, this is not the case.    As follows is the code that I used to generate these. All of the shapes were created using QGIS, and were all created in the same projection.  (It should be noted that the gridding in the picture shown was just to give an idea of the pixel size I was using.)  from osgeo import ogr from osgeo import gdal  aoi_uri = 'AOI_Raster.tif' aoi_raster = gdal.Open(aoi_uri)  def new_raster_from_base(base, outputURI, format, nodata, datatype):      cols = base.RasterXSize     rows = base.RasterYSize     projection = base.GetProjection()     geotransform = base.GetGeoTransform()     bands = base.RasterCount      driver = gdal.GetDriverByName(format)      new_raster = driver.Create(str(outputURI), cols, rows, bands, datatype)     new_raster.SetProjection(projection)     new_raster.SetGeoTransform(geotransform)      for i in range(bands):         new_raster.GetRasterBand(i + 1).SetNoDataValue(nodata)         new_raster.GetRasterBand(i + 1).Fill(nodata)      return new_raster  shape_uri = 'activity_3.shp' shape_datasource = ogr.Open(shape_uri) shape_layer = shape_datasource.GetLayer()  raster_out = 'new_raster.tif'  raster_dataset = new_raster_from_base(aoi_raster, raster_out, 'GTiff',                                 -1, gdal.GDT_Int32) band = raster_dataset.GetRasterBand(1) nodata = band.GetNoDataValue()  band.Fill(nodata)  gdal.RasterizeLayer(raster_dataset, [1], shape_layer, burn_values=[1])   Is this a bug in GDAL, or is RasterizeLayer burning data based on something other than just the presence or lack of a polygon within a specified pixel area?  The files that I was using can be found . The following message keeps appearing on my Samsung Galaxy S4 phone screen about every three seconds  "Unfortunately, Google Play Services has stopped".    Is it actually a virus or it is a problem with the Google Play Service?  I have tried disabling the Google Play Service but the message keeps appearing.  I have Norton Mobile running on my phone to pick up on viruses and to alert me to any possible security issues and also Lookout. They haven't picked up anything.  Does anyone have any suggestions? How was Nearly Headless Nick unpetrified? Show that if $a$ is an odd integer and $b$ is an even integer then $\gcd(a,b)=\gcd(a,b/2)$ Show that if $a$ is an odd en integer and $b$ is an even integer then $\gcd(a,b)=\gcd(a,b/2)$.  I understand that since $a$ is not divisible by $2$ but $b$ is, the gcd of $a$ and $b$ also can't be divisible by $2$ but I'm getting stuck using this to help me.