text:
Ruby Programming/Installing Ruby

The first step to get started in Ruby development is setting up your local environment. Due to differences between various operating systems we will cover multiple of them. If you are already able to use a terminal emulator and know how to install Ruby yourself, you can skip this chapter (after you installed Ruby). Otherwise we will guide you through the process of installing Ruby on your computer.

Terminal emulators
Knowing how to use a terminal emulator is very useful if you are programming. Usually it will provide the most straightforward access to commands and applications instead of hiding it behind graphical interfaces. On the other hand they are often daunting to beginners since they are often perceived to require a deep understanding of a computer when in fact often only knowing the very basics is already enough to get started.

Unix-like operating systems

One of the most commonly used shells in the Unix-like operating systems (i.e. macOS, GNU/Linux, BSD) is the Bash shell, in fact it is very often the default shell. To start a session you will often use a terminal emulator, which allow you to use a terminal session at the same time as other graphical applications. It doesn't really matter, which terminal emulator you use, generally you want one that has color and Unicode support. In macOS you can use Terminal.app which you can find under Applications > Utilities. A popular alternative is iTerm. On most Linux distributions you will usually be provided with at least one terminal emulator by default, otherwise you might want to try Terminator, Konsole, rxvt-unicode or something different.

When you open a new window or tab in your terminal emulator of choice you will be shown your prompt. What it looks like exactly depends a lot on configuration, which can vary greatly from OS to OS (you can configure everything to your likings, however this exceeds the scope of this short introduction). Generally it will indicate your current working directory, username and hostname. When working in the shell your session always has current working directory. Commands that accept relative filenames will use that directory as the base directory to look for files. By default you are in your user's home folder, which is often abbreviated with a tilde.

To execute a command you just type it into the shell and press enter.

At first we want to look at the command  . If you type it in just like that it will print the files and directories in your current working directory. You can also provide a relative path to a directory you want to list, e.g. . If you want more detailed information about the files you can use , if you instead want to also include invisible entries (i.e. names starting with a dot) use. Of course it is possible to combine them both by running  or the short form. Note that this kind of concatenating multiple arguments into one is only possible with single character parameters. Parameters can also come in long form, for example the equivalent of  is. Which forms are available depends on the individual command.

Now you might be thinking how to remember all parameters for every command you will ever use. Thankfully you only want to remember the most important ones, which are the ones you use most frequently, otherwise there is a nice way to look them up. You can either use the   command. For example run  to find more information about the   command. Oftentimes you can find a more concise summary by trying to run the command in question followed by the parameter, however this is not something you can expect to work well with every command, whereas manual pages should be always available.

Back to the topic of current working directories. If you want to change your directory you can use   followed by the directory you want to change to. There are two special virtual directories '.' and '..'. The single dot refers to the current directory while the double dot refers to a dir's parent directory. So executing  changes into the parent directory of the current working directory.

A very brief summary of other useful commands:

System-wide installation
A common and easy way to install Ruby is to perform a system-wide installation. Depending on the operating system installation procedures will be different (if required at all).

Windows
Windows Operating System did not have Ruby programing language pre-installed (unlike other platforms listed here). To install Ruby programming language, it is highly recommended to install it from here:  https://rubyinstaller.org/ .

Refer to right side bar: WHICH VERSION TO DOWNLOAD? for guide to download which version to download. Usually it will recommend the  latest stable version  to be downloaded.

You might see the options of Ruby+Devkit installer version as a selectable component. This option is important as to build native C/C++ extensions for Ruby and is necessary for Ruby on Rails. Moreover it allows the download and usage of hundreds of Open Source libraries which Ruby gems (packages) often depend on.

Download it and double click the file to be installed on the local PC.

Once install it, double click of Ruby Installer to start installing it on Windows

Step 1 : Select "I accept the license" and click "Next" button

Step 2: Select the directory that you wanted to install to and below, select the "Add Ruby executables to your PATH" and "Associate .rb and .rbw files with the Ruby installation". Click "Next" buttons"

Step 3: Select all the checkboxes inside the setup files. Click "Next"

Step 4: Click "ridk install" and click "Next" button to proceed

Once finished installing, type cmd into Window search bar and type  sto see which version of ruby that are installed. If it is showing, congrats, you successfully installed Ruby language in the system.

MacOS_logo_(2017).svg macOS
Ruby comes preinstalled on macOS. To check which version is installed on your system, execute  inside a shell session.

If you want to install a more recent version of Ruby, you can:
 * Update to a newer version of macOS, which may have a more recent version of Ruby.
 * Use RVM or RBEnv tools specifically for managing multiple ruby versions (This is the most popular way because you can manage many Ruby versions and associate them with projects)
 * Use Fink, MacPorts, Homebrew general purpose packaging systems for mac.

Monochrome_Tux.svg Linux
On many Linux distributions Ruby is installed by default. To check if Ruby is installed on your system, run  in a shell session.

Where this is not the case, or you want to update the installed version, you should use your distribution's package manager. Here we will provide information for some popular Linux distributions here, however it is recommended to users of all distributions to familiarize themselves with their distribution's package manager, since this will allow for the most efficient software management. Whether this is a command-line or graphical application depends on the offerings of the distribution and personal preference of the user.

Debian / Ubuntu
The package manager Synaptic provides graphical package management. It is installed by default under Ubuntu and has to be installed manually on Debian (by running  from the command line).

Instead of using Synaptic you can also use apt directly from the command-line (you can find further information in the Debian Wiki's article on Package Management). Execute  from the command line to install Ruby.

Fedora
From the command-line you can install Ruby with DNF by executing.

Arch Linux
Use pacman to install Ruby by executing  as root.

Mandriva Linux
On Mandriva Linux, install Ruby using the command-line tool urpmi.

PCLinuxOS
On PCLinuxOS, install Ruby using either the graphical tool Synaptic or the command-line tool apt.

Red Hat Linux
On Red Hat Linux, install Ruby using the command-line tool RPM.

Per-user Installation
Per-user installations allow each user of the system to utilize their own particular version of Ruby without impact to other users.

Guix
To install the latest available version of Ruby, run:.

Setup Ruby in Windows
Ruby does not come preinstalled with any version of Microsoft Windows. However, there are several ways to install Ruby on Windows.

 * Download and install one of the compiled Ruby binaries from the Ruby web site.
 * Download and run the one click RubyInstaller.
 * Install Cygwin, a collection of free software tools available for Windows. During the install, make sure that you select the "ruby" package, located in the "Devel, Interpreters" category.

Setup Ruby in Windows with Notepad++
In latest version of Ruby and Window 10, it is much more easier to setup Ruby now more than ever.

We will be using to start setup Ruby in Windows.

Once install Notepad++ in Windows, open up the programs and click on Plugins > Plugins Admin

At Plugins Admin, select Plugins , NppExec to install

Once installed, you can run NppExec by pressing F6

Building from Source
If your distro doesn't come with a ruby package or you want to build a specific version of ruby from scratch, please install it by following the directions here. Download from here.

Building with debug symbols
If you want to install it with debug symbols built in (and are using gcc--so either Linux, cygwin, or mingw).

./configure --enable-shared optflags="-O0" debugflags="-g3 -ggdb"

Optimizations
Note that with 1.9 you can pass it  to have it build faster.

To set the GC to not run as frequently (which tends to provide a faster experience for larger programs, like rdoc and rails), precede your build with $ export CCFLAGS=-DGC_MALLOC_LIMIT=80000000 though you might be able to alternately put those in as opt or debug flags, as well.

Testing Installation
The installation can be tested easily by executing:

$ ruby -v

This should produce an output similar to:

ruby 1.8.7 (2009-06-12 patchlevel 174) [i486-linux]

If this shows up, then you have successfully installed Ruby. However if you get an error similar to:

-bash: ruby: command not found

then you did not successfully install Ruby.

de:Ruby-Programmierung: Installation Programmation Ruby/Installation Programmeren in Ruby/Installatie Ruby Programming/Installing Ruby

title: Ruby Programming/Installing Ruby


text:
Ruby Programming/Interactive Ruby

When learning Ruby, you will often want to experiment with new features by writing short snippets of code. Instead of writing a lot of small text files, you can use irb, which is Ruby's interactive mode.

Running irb
Run irb from your shell prompt.

$ irb --simple-prompt >>

The >> prompt indicates that irb is waiting for input. If you do not specify --simple-prompt, the irb prompt will be longer and include the line number. For example:

$ irb irb(main):001:0>

A simple irb session might look like this.

$ irb --simple-prompt >> 2+2 => 4 >> 5*5*5 => 125 >> exit

These examples show the user's input in bold. irb uses <tt>=></tt> to show you the return value of each line of code that you type in.

Cygwin users
If you use Cygwin's Bash shell on Microsoft Windows, but are running the native Windows version of Ruby instead of Cygwin's version of Ruby, read this section.

To run the native version of <tt>irb</tt> inside of Cygwin's Bash shell, run <tt>irb.bat</tt>.

By default, Cygwin's Bash shell runs inside of the Windows console, and the native Windows version of <tt>irb.bat</tt> should work fine. However, if you run a Cygwin shell inside of Cygwin's rxvt terminal emulator, then <tt>irb.bat</tt> will not run properly. You must either run your shell (and <tt>irb.bat</tt>) inside of the Windows console or install and run Cygwin's version of Ruby.

Understanding irb output
<tt>irb</tt> prints out the return value of each line that you enter. In contrast, an actual Ruby program only prints output when you call an output method such as.

For example:

$ irb --simple-prompt >> x=3 => 3 >> y=x*2 => 6 >> z=y/6 => 1 >> x => 3 >> exit

Helpfully,  not only does an assignment, but also returns the value assigned to , which <tt>irb</tt> then prints out. However, this equivalent Ruby program prints nothing out. The variables get set, but the values are never printed out.

x=3 y=x*2 z=y/6 x

If you want to print out the value of a variable in a Ruby program, use the  method.

x=3 puts x

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Ruby Programming/Interactive Ruby


text: Template:Python Programming/Navigation Start


text: Template:Python Programming

title: Template:Python Programming


text:
User talk:Yath~enwikibooks

Nobody likes a red link... ... and nobody likes yath

Hi Yath thanks for making the BIG images on Tmxxine into thumbnails :-) Can you do anything about ASQ? 82.69.58.117 06:02, 25 Sep 2004 (UTC)

 * You're welcome! By the way, Wikipedia has some good pages on images: w:Wikipedia:Extended image syntax and w:Wikipedia:Picture tutorial. --Yath 15:38, 25 Sep 2004 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Yath. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Yath~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:54, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:39, 19 April 2015 (UTC)

title: User talk:Yath~enwikibooks


text:
Australian History/Preface

‹ Return to the Contents

Authors should maintain the regular wikibook rules governing unbiased writing, the only other guideline are that everything should be kept more or less in chronological order and divided into logical chapters. Everything else is left pretty much up to the individual authors that elect to join into the project. There are some excellent examples of Wikibooks covering history, including Canadian History, and the Australian History Wikibook is modeled on these.

The eventual aim of this project is to create a textbook which could, in printed form or online, be a useful resource for high school and university students studying Australian history, and could even be used (in printed form) as the main textbook for a high school or university subject. For more details on this, please see Textbook Standards in Australia. More specific details for creating a Victorian textbook are available from the VCAA, including the Study design guide.

As of the time of writing, some of the VCE "Australian History" course requirements were as follows:
 * Unit 1 covers "Twentieth Century History" (1900-1945)
 * Area of Study 1 covers Crisis and Conflict from 1900-1945
 * Outcome 1 calls on students to analyse the crises and conflicts in this period
 * Area of Study 2 covers changes to "Social life" in the first half of the twentieth century, in relation to social and economic changes caused by events like the Depression, and the World Wars
 * Outcome 2 calls on students to analyse and discuss these changes
 * Area of Study 3 covers "Cultural Expression" in the first half of the Twentieth Century, and its relation to cultural, political, and economic changes in this period
 * Outcome 3 calls on students to analyse the links between cultural expression, and cultural, political, and economic changes in this period

 * Unit 2 covers "Twentieth Century History" (1945-2000)
 * Area of Study 1 covers the Cold War ideas and political power
 * Outcome 1 calls on students to analyse how Cold War societies legitimised their worldviews
 * Area of Study 2 covers "social movements" which emerged during the cold war (e.g. feminism, gay and lesbian rights, etc.)
 * Outcome 2 calls on students to evaluate the impact of these challenges
 * Area of Study 3 covers "Issues for the new millenium"
 * Outcome 3 calls on students to analyse political, economic, or technological challenges being faced in the new millennium.

 * Unit 3 covers "Australian History"
 * Area of Study 1 covers "The Port Phillip District" (1830-1860)
 * Outcome 1 covers the motives and hopes of settlers, and the impact on Indigenous Australians
 * Area of Study 2 covers "Nationalism, Race and Citizenship" (1888-1914)
 * Outcome 2 is an analysis of the ideas behind the new nation and their implementation

 * Unit 4 covers "Australian History"
 * Area of Study 1 covers "Testing the new nation" (1914-1950)
 * Outcome 1 requires students to analyse how Australians reacted to a crisis in this period
 * Area of Study 2 covers "Debating Australia's Future" (1960-2000)
 * Outcome 2 requires students to examine Australian attitudes to either:
 * The Environment
 * Vietnam War
 * Indigenous Rights
 * Immigration

Forward to the Introduction ›

title: Australian History/Preface


text:
Cookbook:Lemon Meringue Pie (British)

| Dessert | UK Cuisine

These instructions will make a sticky and indulgent lemon meringue pie. If you want the American gel-like centre, use the other recipe instead.

Ingredients

 * 8 digestive biscuits (plain/tea biscuits)
 * 2 imperial tbsp (36 ml / 2.4 US tbsp) butter
 * 1 tin (300 ml) sweetened condensed milk
 * 1–2 lemons, zested and juiced
 * 1 egg yolk
 * 3 egg whites
 * 6 imperial tbsp (108 ml / 7.2 US tbsp) caster sugar

Procedure

 * 1) Pound the digestive biscuits into crumbs with the end of a rolling pin.
 * 2) Add sufficient melted butter to the crumbs to make the mixture cohesive. Mix well, then press it into the bottom of a 10 inch (25 cm) diameter, 1 inch deep pie dish. Press down firmly with the tip of a spoon to make the base.
 * 3) Combine the sweetened condensed milk and egg yolk. Stir gently, then mix in the lemon zest and juice to taste—more will be better, but be careful not to add too much or it will spoil the texture. Do not stir too much.
 * 4) Pour the filling into the pie dish, covering the biscuit layer.
 * 5) Whip the egg whites until foamy. Gradually beat in the sugar until you get stiff peaks.
 * 6) Spoon the meringue into the pie dish, sealing around the edges.
 * 7) Bake in a moderately cool oven (325 °F / 162 °C) for about 45 minutes until the meringue is a light golden brown. The aim is to cook the meringue and partly cook the centre (unlike, say, Baked Alaska, where only the top of the meringue is flash-cooked).
 * 8) Remove from the oven, allow to cool, and place in the refrigerator for 2 hours to set.
 * 9) Enjoy.

Notes, tips, and variations

 * There are 2 types of lemon meringue pie. The more common version has a lemon "gel" in the centre (which is often a luminous yellow colour), and a hard pastry base. The version above is much stickier.
 * In an earlier version, the filling used 3 egg yolks. It isn't necessary.
 * When making the middle, it's essential to mix in the egg before the lemon. The acidity of the lemon acts on the yolk protein to thicken it; putting in the lemon first (which is tempting if you want to "add lemon to taste" without eating raw egg yolk) will cause the yolk to go "stringy" on contact.

title: Cookbook:Lemon Meringue Pie (British)


text:
Australian History/Authors

Australian History/Contents

 * Original Author: Ruszewski
 * Principal Author:
 * Chief Contributor of Images:

Contributors
(In Alphabetical Order - please sign using four '~')
 * AmishThrasher 08:56, 21 September 2005 (UTC)
 * Mbrickn (discuss • contribs) 17:42, 12 November 2020 (UTC)

title: Australian History/Authors


text:
Talk:Australian History/Authors

I'm going to move this module to Australian History:Authors, otherwise every wikibook will try to list their authors on this page. Gentgeen 06:01, 25 Sep 2004 (UTC)

title: Talk:Australian History/Authors


text:
User talk:Eibwen

Hi there, noticed your comments about CSS and wonder if you can add something to the ASQ pages perhaps in the Programmer section or where you feel appropriate :-)

--82.69.58.117 06:05, 25 Sep 2004 (UTC)

 * I'll look over the pages, however given that I have never heard of ASQ, I doubt I can make a significant contribution.

 * --Eibwen 09:08, 25 Sep 2004 (UTC)

title: User talk:Eibwen


text:
User talk:203.130.245.190

Hi there noticed your abilitity to change spelling mistakes - probably made a few here [ASQ] - Any help appreciated 82.69.58.117 06:07, 25 Sep 2004 (UTC)

title: User talk:203.130.245.190


text:
Talk:Curl

cURL is an open source console based download utility. It is also the first result for the google search curl.

CURL is a programming language developed at MIT

as well as a corporation and a host of other things.

--Eibwen 06:15, 25 Sep 2004 (UTC)

Should this become Curl Programming Language? Lobster 06:48, 26 Sep 2004 (UTC)

title: Talk:Curl


text:
User:Nouhad~enwikibooks

Nouhads Wiki Page.. Testing this

title: User:Nouhad~enwikibooks


text:
Electronics/Superposition

Superposition Principle
(a)

(b)

(c)
 * Figure 1: The circuits showing the linearity of resistors.

Most basic electronic circuits are composed of linear elements. Linear elements are circuit elements which follow Ohm’s Law. In Figure 1 (a) with independent voltage source, V1, and resistor, R, a current i1 flows. The current i1 has a value according to Ohm’s Law. Similarly in Figure 1 (b) with independent voltage source, V2, and resistor, R, a current i2 flows. In Figure 1 (c) with independent voltage sources, V1 and V2, and resistor, R, a current i flows. Using Ohm’s Law equation 1 is reached. If some simple algebra is used then equation 2 is reached. But V1/R has a value i1 and the other term is i2 this gives equation 3. This is basically what the Superposition Theorem states.

 * $$i=\frac {V_1+V_2}{R}$$(1)
 * $$i=\frac {V_1}{R} + \frac {V_2}{R}$$(2)
 * $$i=i_1+i_2 \, $$(3)

The Superposition Theorem states that the effect of all the sources with corresponding stimuli on a circuit of linear elements is equal to the algebraic sum of each individual effect. Each individual effect is calculated by removing all other stimuli by replacing voltage sources with short circuits and current sources with open circuits. Dependent sources can be removed as long as the controlling stimuli is not set to zero. The process of calculating each effect with one stimulus connected at a time is continued until all the effects are calculated. If kth stimulus is denoted sk and the effect created by sk denoted ek.

 * $$\sum_{k=1}^N e_k$$(4)

The steps for using superposition are as follows:
 * 1. Calculate the effect of each source in turn with all other independent voltage sources short circuited and independent current sources open circuited.
 * 2. Sum these effects to get the complete effect.

Note: the removal of each source is often stated differently as: replace each voltage source with its internal resistance and each current with its internal resistance. This is identical to what has been stated above. This is because a real voltage source consists of an independent voltage source in series with its internal resistance and a real current source consists of an independent current source in parallel with its internal resistance.

Superposition Example

 * Figure 2: The circuit for the example.

Problem: Calculate the voltage, v, across resistor R1.

Step 1: Short circuit V2 and solve for v1. By voltage divider rule.
 * $$v_{1}= \frac {V_1(R_1 | | R_3)}{R_2+(R_1 | | R_3)}$$(5)

Short circuit V1 and solve for v2. By voltage divider rule.
 * $$v_{2}= \frac {V_2(R_1 | | R_2)}{R_3+(R_1 | | R_2)}$$(6)

Step 2: Sum the effects.
 * $$v=v_1+v_2 \,$$

Using equations 5 and 6.
 * $$v=\frac {V_1(R_1 | | R_3)}{R_2+(R_1 | | R_3)}+\frac {V_2(R_1 | | R_2)}{R_3+(R_1 | | R_2)}$$

If $$R_1=R_2=R_3=2k \Omega$$ and $$V_1=V_2=15V$$ then
 * $$v=\frac {15(2k | | 2k)}{2k+(2k | | 2k)}+\frac {15(2k | | 2k)}{2k+(2k | | 2k)}$$
 * $$v=\frac {15(1k)}{3k}+\frac {15(1k)}{3k}$$
 * $$v=10V \,$$

title: Electronics/Superposition


text:
Talk:Geometry for Elementary School/Why are the constructions not correct?

Aside from the awkward grammar, this page should be merged with whatever it refers to...

How about not having this under "Geometry for elementary school". Come on, this is advanced stuff.

 * I agree, and half of it is written in first person. I also don't remember getting into this in elementary school... NinjaSkitch (talk) 03:53, 11 December 2007 (UTC)

"I must admit that I never could copy the segment accurately"
is it ok? "i must admit.."?

"I must admit that I never could copy the segment accurately"
is it ok? "i must admit.."?


text:
Talk:Open Source

Discussions lacking a subject
We have launched a project o open source project modelling.

--

There are a myraid of Open Source projects. While I appreciate your interest in Open Source, please make project announcements on appropriate sites (eg SourceForge and FreshMeat). The context of this page is the notion of "Open Source" and the respective liscenses -- NOT a trove of Open Source software.

Moreover, if you actually bothered to read the page, you would note that the context is (incorrectly) NOT Open Source, but rather Freeware.

--Eibwen 08:28, 25 Sep 2004 (UTC)

Is there really a point to creating yet another trove?

--146.244.186.42 04:29, 26 Sep 2004 (UTC)

a definitve resource
I feel it is quite resonable to provide as part of Wikiversity a definitive (and updated) unbiased list of resouces for study Lobster 15:34, 26 Sep 2004 (UTC)

 * While I agree with the spirit of your statement, I disagree with its applicability. There are several established troves of freeware (and open source) software, notably C|Net's Download.com, SourceForge, and FreshMeat.  If this page is to be a definitive listing, it would have to address the myriad of individual titles available -- essentially mirroring other established troves.

 * I do not believe this to be in the interest of this wiki.

 * HOWEVER, I would not object to a listing of the leading applications for each category -- and ONLY the leading application. Anything beyond that would constitute a trove and thus be subject to the discussion above.

 * --Eibwen 04:51, 27 Sep 2004 (UTC)

Sometimes there are several leading packages which suit choice, circumstance and preference

The source links you suggest are not suitable for beginners and others who would find the layout confusing

The page is not designed as a trove but as an impartial source that does not have a commercial, open source or other agenda to promote to the detriment of end users.

Though open source is the ideal it does not always have the best available software - therefore creating a page that combines the ideas of Open Source with what is of most use, is an educational stance in the spirit of wiki books and not some pedantic insistence on the absolute.

I hope you have taken the time to add your links to the links section?

Lobster 05:10, 27 Sep 2004 (UTC)

Why a simple software listing?
Why does it seem to be the standing assumption that a book about Open Source software should be about what software is out there? I would agree with those that have commented above that we have more then enough of those in the world already, and how would that be a book anyway? There is a great deal of philosophy in the open source movement, and a great deal to be written about open source project management. To me a BOOK on open source should cover those issues. Only after those issues were discussed would a specific listing of software be included. While these issues can be hinted at in the wikipedia article, to keep to the reasonable length requirements of the pedia it makes sense that detailed discussions about the philosophy, history, debates, lessons learned, case studies and other related discussions would be the topic of a full length book (indeed there are books like that in print). Where else should a detailed discussion of the difference between the GPL and BSD licences find a proper home? Or an explination of the difference between free software and open source software? Ahc 05:55, 28 Nov 2004 (UTC)

Hi Ahc and everyone - I hope you will take the fat from the freeware page and wikipedia and place it here where some of the important issues - such as the politics, the future, relationships between groups, legal standing and other up to date sections such as OS NEWS can be explored -

also the removal indication -which some people with a monitor fixation are too keen on - whilst those with real personality are modifying and adapting NEEDS TO BE CLEARED or the page should go - if this indication appears I tend to abandon the page as the useless 'experts' rarely attempt to improve or advise they just criticise and remove - yuk. Fortunately some of the more experienced, genuine moderators are more understanding of how sometimes these things take time to develop. . . Good luck I hope you manage to make something of this Lobster 05:46, 5 Dec 2004 (UTC)

 * Okay, I'm starting the process of giving this book better direction. Over the next couple days I'm going to be rather aggressive in pruning, and re-outlining the old material in the book, and starting to create new material.  If anyone had ideas I'd love to hear them.  I expect to copy/move some material from the freeware book and wikipedia articles as appropreite (at least in my opintion). --Ahc 04:47, 6 Dec 2004 (UTC)

Logo
Lobster thanks for the logo. I personally would prefer something a little more suttle, but that's just my taste in logos. I didn't bother to create one, so I'm not really one to complain. Thanks. --Ahc 14:00, 8 Dec 2004 (UTC)

It is kind of the best I could do and just a small contribution to encourage your efforts

I am trying to get this wiki going

http://peace.wikicities.com/index.php/Main_Page

it is getting a little New Agey - so if you are an atheist your contributions would be welcome

82.69.58.117 17:28, 8 Dec 2004 (UTC)

open source books and links
http://phptr.com/promotion/1484?redir=1

History Section
I love it if someone familiar with the history of BSD would help out with the history section. I will work on reviewing the Wikipedia article on it for material, but I know much more about the emergance of GNU. --Ahc 03:32, 9 Dec 2004 (UTC)

Licenses
I'm trying to figure out how to do this section. I have two questions that I'm not sure about.

 * 1) Should the section include the text of the licenses?
 * 2) If so, what are the rules about posting them?  Most (all?) are copyrighted texts, but the authors request that they be shared.  What are wikibook's rules about this, does anyone know?

--Ahc 05:31, 12 Dec 2004 (UTC)

I would suggest highlights and links to the full text To be honest I feel there two many liscences and they are confusing

so some form of line from no restrictions to open but restrictions would be useful (if indeed it can be delineated in this way)

 * Since there are so many licenses out there I was only going to look at a couple of the most popular and therefore important, GPL, BSD, Apache. They cover most of the important differences between the types.  If others should be included feel free to suggest them.
 * --Ahc 15:39, 1 Jan 2005 (UTC)

Great info guys - here is a link that I came across and thought of this project

http://www.dwheeler.com/oss_fs_why.html

82.69.58.117

What is open source?
The recently added material in what is open source concerns me a little. Some suggestions from the peanut gallary would be helpful here. The material is from the OSI web site which is licenced under the Open Software Licence and the Acedemic Free Licence. OSL requires that all dirivative works are licenced under the OSL, but the AFL has no such requirements. Since Wikibooks is licenced under the GNU Free Documentation Licence it does not meet the requirements of the OSL but it should be okay under AFL. Anyone know what the write answer is here? --Ahc 20:08, 9 Jun 2005 (UTC)

 * Things can be dual licensed, but the GNU's FDL pretty much cannot be added to anything that already had a license with any restrictions that the FDL doesn't itself impose and things licensed under the FDL cannot be relicensed under anything that adds restrictions. Nmontague 23:46, 20 August 2005 (UTC)

Suggest Title Change
Given that this book discusses both Open Source Software and Free Software, I would suggest changing the title to FOSS or FLOSS (Free and Libre Open Source Software).

title: Talk:Open Source


text:
Talk:Introduction to Philosophy/Why Study Philosophy?

Consider mentioning ontological questions.

--Eibwen 08:30, 25 Sep 2004 (UTC)

'Philosophy truly becomes worthwhile when it changes your life.' Perhaps there should be a caveat or two here. Philosophy can open your eyes, and you might not like what you see. Don't study philosophy, just get a routine job and live a routine life and don't ask questions! Do you really want to live like Diogenes or Wittgenstein? --publunch 07:27, 29 Oct 2004 (UTC)

The topic is "Why study Philosophy?" not "Why not study Philosophy?" For those who are up to the challenge, a clear, honest appraisal of life and the universe around us is genuinely liberating from the coercion of dominant paradigms, and can lead to freedom from dependencies, destructive habits and mental disarray. Whether you choose to focus on negative or positive outcomes reflects your personal philosophy, as does your questioning of values and lifestyles.


text:
Talk:Music Theory/Introduction

The page shouldn't attempt to justify itself, rather it should merely state the content. Frankly the content is greatly obscured by its own justification.

--Eibwen 08:36, 25 Sep 2004 (UTC)

title: Talk:Music Theory/Introduction


text:
Cookbook talk:Kosher

It would be interesting if you could provide the actual passages. Interpretation of Kosher may be at least partially subjective, but the passages themselves are not.

Additionally, it would be beneficial to find an image of the symbols used to denote a product is Kosher.

--Eibwen 09:34, 25 Sep 2004 (UTC)

There are restrictions on plants, such as eating fruit from trees only after they are at least three years old, but I do not know the details.

--ALW, 11 Sep 2005

Hey there is a certain type of apple which isn't kosher figure what it is called please

I think it might be called ______ shiny apple

Also there is a certain of lettuce maybe it was cabbage which contains so many bugs it is impossible to remove the bugs.

Fruit from a tree less than three years old is not permitted. In practice I've never heard of anyone refusing fruit bought in a store. There are enough symbols to fill a few pages (for example every country has its own set), but the most widespread is the OU or Orthodox Union symbol. I this this might make an ideal image. All fruits/vegetables are kosher. Some choose not to eat lettuce and cabbage because of the effort required to ensure the food free of insects. I've never heard of this 'shiny apple'. 71.106.118.239 05:19, 6 April 2006 (UTC)userbeliever

Also the

Catfish
Since when do catfish not have fins? --Gbleem 23:06, 29 March 2006 (UTC)

Catfish do have fins but are bottom feeders, which are not allowed. Incedentally, correct placement/number of fins is also required, as well as visible (not shark- or ray-like) scales. 71.106.118.239 04:59, 6 April 2006 (UTC)userbeliever

Terrible Cookbook in need of improvement
This is a really terrible cookbook. The information here is less in depth than the english wikipedia article on kosher, and doesn't have a single recipe. Legitimately, as a religious Jew, I can see no value here for either kosher observant people or non-kosher observant people who want to prepare a kosher meal. This article should be restarted from scratch. TimeEngineer (discuss • contribs) 05:08, 10 March 2021 (UTC)

title: Cookbook talk:Kosher


text:
Talk:Physics with Calculus/Mechanics/Velocity and Acceleration

While density is defined as the ratio of mass to volume, mass is not defined in terms of density. Such a definition would be circular. Moreover the abstracted reference to Special Relativity is inappropriate given the context.

Moreover, the title states "Calculus-based", yet no differentials were used. Frankly I think this adjective should be removed and the page should include both the integral/differential form as well as the general (algebraic) form.

--Eibwen 09:52, 25 Sep 2004 (UTC)

I removed the $$m = \rho v$$. I agree that this page needs to be reworked, but I do not see how the reference to Special Relativity is inappropriate. The title is "Conservation of Mass" which is "violated" given the right circumstances. As long as it remains as a reference, it is fine in my opinion.

--jeffpc 04:22, 30 Oct 2004 (UTC)

'Moved the entire page under a new heading. There is really no need to mention conservation of mass in this physics textbook (and not at this early (i.e. Part I) stage) (as we don't deal with chemical/nuclear reactions too much), and if anything, conservation of mass would be useful for something analogous to Continuity Equation of EM (or... does it go by the same name in mechanics?), but that's related to fluid mechanics, which probably won't get added until this book is more mature. So, I moved the page under new heading so that there's no orphaned page or a to-be-worked-on page that's left hanging.... novakyu 08:38, 19 Dec 2004 (UTC)

I agree with what's been said. The stuff here seems irrelevant. I would suggest some kinematics first, i.e. no mentions of mass, yet. At least, not till we get to Newton and dynamics.

Define displacement, velocity, and acceleration; and then the kinematic equations. That's one good chapter, there. Yeah, I guess I'm a traditionalist.

--Drauh 10:23, 23 Dec 2004 (UTC)


text:
Talk:Numerical Methods

Plans for this book
I think a WikiBook on Numerical Methods is a very good idea and was therefore happy to find that one had already been started. I notice that currently there is no content at all. Does someone already have plans for putting in content?

I will be teaching a course on Numerical Solutions of Differential Equations in the spring term and that will be a good opportunity for me to contribute. Gustav

title: Talk:Numerical Methods


text:
Talk:Introduction to Philosophy/Origins of Philosophy

I am taking a new approach on this. The old version of this text was completely incomprehensible and strayed far from what I would consider an introduction. Although this is the first step and there is much to be edited, I would like to continue working in this manner until the end of each part. Afterwards, it would be easier for me to edit. That is, when I have more time to take in each idea and pay more attention to its own attention to the subject. Also, I will be trying to transform these discussion pages into a comprehensive discussion on Philosophy. --Destrogal 21:09, 30 Jun 2005 (UTC)

I love the idea that earth was formed from water by the mind. I think it's a wonderfully literal extension of the idea that one's reality is a product of thier own perception.

I'm sorry but the author of this article just doesn't have a sufficient grasp of English to be writing articles on philosophy. It's too big of a mess to even consider editing it. Someone should start again from scratch. My apologies to the original author.

I was thinking of participating in this project and contributing to it, but I have a question to those who watch this page and this project. This introduction to philosophy is written in part in the first person, and that makes it hard for me to know how to jump in and contribute, because it's someone else's "I". Has there been some agreement about the mode or style of this textbook, in terms of what voice or person it will be written in? It's not even that I'm objecting to an introduction to philosphy being written in the first person, but rather that I can't figure out how to be part of a collective or group that is writing in that mode. In any case, I'd be grateful for any insight you can provide. Jjshapiro (talk) 00:18, 4 July 2008 (UTC)

Etymology edit
Hope you don't mind but I edited the section on the origin of the word "philosophy". I don't know if that was right but I felt that keeping the etymological article short would allow the reader to ease into this vast subject. --Sluffs (talk) 01:25, 24 July 2009 (UTC)

Love is selfish, crucial, cruel with good intents of care;freedom, trust and honesty Mtyeku Kuhle (discuss • contribs) 20:58, 30 April 2018 (UTC)

Non-Greek Origins of Philosophy
This article should be updated to provide a sourced and balanced view of the Jaeger/Guthrie view of 'Western philosophy starts with Thales' versus the 'The Greeks stood on the shoulders of non-Greek giants' view put forward by scholars such as Kingsley, Christos C Evangeliou and Algis Uzdavinys. As it stands, it is biased in that it does not put forward the views of Classical scholars who acknowledged their debt to other cultures.

The unsigned comment above is valid and the real issue is religion. The Pantheon of deities that Homer describes (excluding local Greek deities) are related to Babylonian deities as well as a whole host of other Eastern deities. Man's first attempt to explain the world he lived in and how he experienced it begins with the old "hey lets worship that big bright object in the sky that gives us warmth" or "that was a great hunt and my wife's really happy about the woolly mammoth steak sandwiches she can make so I will draw a picture of our experiences of the hunt on our cave wall to celebrate" and other such ideas including ancestors, each other, meteorites, eclipses, disease, etc. Also the Greeks themselves framed their experiences accordingly. Plato is not a rational philosopher in the modern agnostic sense and quite often references the pantheon of deities that were worshiped in his time. I don't know the authors mentioned above but any chapter titled "Origins of Philosophy" should start with a brief discussion of religion. Probably this reply is bit late but if no one minds I will try to put something together along those line.

Sluffs (discuss • contribs) 00:57, 23 July 2014 (UTC)

Broken link
Hi, It seems that I can't access the website at the bottom of this chapter. Can anyone confirm this to me please? I am currently translating this wikibook into Thai. -Thas Tayapongsak (discuss • contribs) 17:40, 24 September 2021 (UTC)


text:
Talk:Pro Engineer/Create Features

Is this a basic tutorial or is it within the context of Pro/Engineer philosophy and methodology?

--Eibwen 16:53, 25 Sep 2004 (UTC)

 * I think this should be within the context of Pro/Engineer philosophy, inasmuch as it is necessary to understand some Pro/Engineer philosophy in order to use Pro/Engineer properly. That said, "How to make a protrusion" need not necessarily go into deep philosophical detail about references.  --Dvortygirl 06:57, 23 October 2005 (UTC)

title: Talk:Pro Engineer/Create Features


text:
Modern Physics/Gravitational Red Shift

The red shift
Spacetime diagram for explaining the gravitational red shift.

Light emitted at a lower level in a gravitational field has its frequency reduced as it travels to a higher level. This phenomenon is called the gravitational red shift.

We can see why this happens by using the principle of equivalence. Being in a gravitational field is equivalent to being in an accelerated frame, so knowing how the doppler shift works in such a frame will tell us how it works in a gravitational field.

We view the process of light emission and absorption from the unaccelerated or inertial frame, as shown in the figure above. In this reference frame the observer of the light is accelerating to the right, as indicated by the curved red world line, which is equivalent to a gravitational force to the left.

The light is emitted at point A with frequency $$\omega$$ by a source which is stationary at this instant. At this instant the observer is also stationary in this frame. However, by the time the light gets to the observer, they have a velocity to the right which means that the observer measures a Doppler shifted frequency $$\omega'$$ for the light. Since the observer is moving away from the source, $$\omega'<\omega$$, as indicated above.

The relativistic Doppler shift is given by

 * $$ \frac{\omega'}{\omega} = \sqrt{ \frac{1 - U/c}{1 + U/c}}, $$

so we need to compute U/c. The line of simultaneity for the observer at point B goes through the origin, and is thus given by line segment OB. The slope of this line is U/c, where U is the velocity of the observer at point B. From the figure we see that this slope is also given by the ratio X' /X.

Equating these, eliminating X in favor of L = √(X2 - X′2), which is the actual invariant distance of the observer from the origin, and substituting into the previous equation results in our gravitational red shift formula:

 * $$\begin{matrix}

\frac{\omega'}{\omega} & = & \sqrt{ \frac{X - X'}{X + X'} } & = & \sqrt{\frac{(L^2 + X'^2 )^{1/2} - X'}{(L^2 + X'^2 )^{1/2} + X'} }\\ & =& \frac{(L^2 + X'^2 )^{1/2} - X'}{L} & =& \frac{X-X'}{L} \end{matrix}$$

If X′ = 0, then there is no redshift, because the source is collocated with the observer. On the other hand, if the source is located at the origin, so X′=X, the Doppler shifted frequency is zero. In addition, the light never gets to the observer, since the world line is asymptotic to the light world line passing through the origin. If the source is at a higher level in the gravitational field than the observer, so that X′ < 0, then the frequency is shifted to a higher value, i. e., it becomes a blue shift.

To see how this doppler shift relates to the strength of gravity, g, and the distance h between the source and the observer, first note that

 * $$L=\frac{c^2}{g} \qquad X-X'=L-h $$

Making these substitutions gives

 * $$\frac{\omega'}{\omega} = 1-\frac{gh}{c^2} \qquad (1)$$

So the redshift is proportional to gravity.

Since this doppler shift doesn't depend on the type of wave we can conclude that it is actually caused by time dilation, just like the doppler shift due to relative motion.

That is, gravity slows down time.

Energy and frequency
In equation 1 gh is the change in gravitational potential energy so the change in frequency is proportional to change in potential energy, which suggests there might be a connection with energy conservation.

However, since we haven't yet established any connection between frequency and energy, we can't simply apply a energy conservation argument. Instead, we can argue in reverse, finding out what the energy-frequency relationship must be is energy is to be conserved.

Suppose we have two identical systems, both at rest in a uniform gravitational field g with initial energy E separated by a vertical distance h.

The system has mass E/c2, giving it potential energy, so the total energy of the two systems is initially

 * $$E_i=2E - \frac{gh}{c^2}E $$

where the second term is due to the lesser potential energy of the lower system.

The lower system emits a burst of waves, frequency ω, energy E(ω). When this reaches the upper system the waves have been red-shifted to frequency ω', energy E(ω'). This energy is absorbed by the upper system.

The total energy is now

 * $$E_f=E-E(\omega)+E+ E(\omega') - \left(E-E(\omega)\right)\frac{gh}{c^2}

$$

Since we want to preserve energy conservation, these two equations must give the same result. Equating them, we get

 * $$E(\omega') = E(\omega)(1-\frac{gh}{c^2})$$

Comparing this with the doppler shift we see that

 * $$\frac{E(\omega')}{E(\omega)} = \frac{\omega'}{\omega} $$

which can only be true if E(ω) is proportional to ω

I.e, energy conservation implies energy is proportional to frequency, which is one of the axioms of quantum theory.

We could equally well have started with the quantum result and proved the gravitational red shift must exist. Either theory requires the other for consistency.

Since energy and frequency are each the temporal components of a four-vector, their being proportional implies the four-vectors themselves, and their spatial components, are also proportional. So, for waves, momentum is proportional to k.

Remember too, we saw earlier, when we looked at Hamilton's equations, that classical mechanics would be equivalent to a theory of anisotropic waves, in the geometrical optics limit, if energy were proportional to frequency and momentum to wave number. This proportionality isn't just required for energy conservation, it would make possible a theory uniting waves and particles.

None of this actually proves the proportionality, doing that requires experiment, but it does make it a natural assumptiom, which is indeed confirmed by experiment.

Because of all this, from now on we'll assume that energy and frequency are related in this way, with the constant of proportionality being $$\hbar$$

 * $$ (c\mathbf{p}, E) = \hbar (c\mathbf{k}, \omega)$$

Gravity and curvature
The gravitational redshift also implies that space is curved. We can see this by considering a rectangle in space-time.

Without gravity, if we start at some point A, wait for time t, then move at light-speed to the right for a distance h, we get to the same place, B, as if we move at light-speed for a distance h then wait for time t at rest with respect to A.

With gravity, if we follow the first path, we rise a distance of ct then wait for time t. On the second path, we begin by waiting for time t, but this is dilated by gravity. To an observer at B we appear to be waiting for a time t(1+gh/c2) before we start, so we end up at B later than on the first path.

Thus, with gravity, it matters which order we add distance vectors in. This can't happen if space is flat, so space must be curved.

To describe how it's curved we'd need the techniques of General Relativity.

title: Modern Physics/Gravitational Red Shift


text:
User talk:Wfg

Hallo Wfg,

falls du mal wieder hier reinschauen solltest: Wir sind inzwischen umgezogen; die deutschen Wikibooks finden sich jetzt unter de.wikibooks.org. Ich bin gerade dabei dein angefangenes Buch "Radiologie" dorthin zu verschieben. Die Bilder werde ich aber nicht umziehen, da diese ungenügend lizensiert sind. Sie müssen den Vermerk "GDFL" oder "public domain" enthalten, sowie den Autor bzw. die Herkunft. Es genügt also die Anmerkung "selbsterstellt, GDFL". (Bei Fragen bitte auf de:Benutzer Diskussion:Berni antworten...) --berni 19:02, 25 Sep 2004 (UTC)

title: User talk:Wfg


text:
Talk:Alchemy

dict.org entries for 'alchemy'
2 definitions found for alchemy

 * You are an amusing fellow. I hope you will add your definitions to the 'Alchemy'page and

hope you do not require dictionary defintions to smile :-) Lobster 05:56, 27 Sep 2004 (UTC)

I sincerely hope you will add some of your defining ideas to the alchemy page

It would be a delight to correct them

Many thanks for your suggestions and comments Lobster 05:56, 27 Sep 2004 (UTC)

From Webster's Revised Unabridged Dictionary (1913) :

Alchemy \Al"che*my\, n. [OF. alkemie, arquemie, F. alchimie, Ar.    al-k[=i]m[=i]a, fr. late Gr. ?, for ?, a mingling, infusion,     ? juice, liquid, especially as extracted from plants, fr. ?     to pour; for chemistry was originally the art of extracting     the juices from plants for medicinal purposes. Cf. Sp.     alquimia, It. alchimia. Gr. ? is prob. akin to L. fundere to     pour, Goth. guitan, AS. ge['o]tan, to pour, and so to E.     fuse. See Fuse, and cf. Chemistry.]     1. An imaginary art which aimed to transmute the baser metals        into gold, to find the panacea, or universal remedy for        diseases, etc. It led the way to modern chemistry.     2. A mixed metal composed mainly of brass, formerly used for        various utensils; hence, a trumpet. [Obs.]              Put to their mouths the sounding alchemy. --Milton.     3. Miraculous power of transmuting something common into something precious. Kissing with golden face the meadows green, Gilding pale streams with heavenly alchemy. --Shak.

From WordNet (r) 2.0 :

alchemy n 1: a pseudoscientific forerunner of chemistry in medieval times 2: the way two individuals relate to each other; "their         chemistry was wrong from the beginning -- they hated each          other"; "a mysterious alchemy brought them together" [syn: chemistry, interpersonal chemistry]

You will note that all but two definitions (Webster's Revised Unabridged Dictionary (1913) - definition 3; WordNet (r) 2.0, definition 2) relate solely to metallurgy. The other two use the term as a literary device in a metaphorical sense.

Please fully cite your sources that contradict these definitions.

Perhaps you would be good enough to find these and add them to the page?

If you are unable to then I must conclude that Alchemy is little more than you suggest

Perhaps anywhere other than reference material might be a start Lobster 05:56, 27 Sep 2004 (UTC)

--Eibwen 05:09, 27 Sep 2004 (UTC)

Structure and goals
''1. An imaginary art which ... led the way to modern chemistry.''

*snerk* Interesting how something they claim is imaginary could lead the way to anything.

I was delighted to see there was a book on alchemy, but I do think the structure and organization as suggested in the TOC needs some serious work. I'll see if I have time to think about it this weekend. (That's beyond the header levels, which are messed up right now -- everything under "Relationship to Chemistry and Physics", for instance. Unfortunately, it's five to midnight and I'll be lucky if I finish this comment coherently, much less trying to fix the headers.)

However, before the structure can be finalized, I think some of the book's basic goals need to be clarified. What is the purpose of this text--what is it intended to teach, and why? Who are the audience, what do they already know about the topic, and what do they want to learn? What should they have gained after reading it that they didn't have when they started, and how are they going to use that information?-Bedawyn

 * It is intended to teach what it becomes - I hope that makes some sense. What people gain whether in construction or in reading is dependent on intent. I suppose the question will be answered during the construction. Lobster 17:41, 2 Oct 2004 (UTC)

It seems from your mention of "operative alchemy" that you're aiming for a practical text, but the actual organization of the TOC seems only partly practical, partly theoretical, historical, and cultural. I actually think the latter would work better, if only because there's a much larger audience for an introduction to the ideas of alchemy than for an introduction to the practice of alchemy. Maybe a book focusing more on the practice would be suitable for a followup, if there's enough public domain sources to work with. (I suspect there are... I know I've seen at least a few of the old occult texts at Internet repositories, and it might be interesting to seek out and maybe interview some of the modern practitioners.) -Bedawyn

 * most occultist practice befuddlement - first of themself and then others ;-) However you are more than welcome to structure and arrange in way you like Lobster 17:41, 2 Oct 2004 (UTC)

Accuracy dispute
Eibwen, can you specify exactly what part of the module you are disputing? The few specific paragraphs need some work for citations and NPOV, but overall, there's not a lot there yet to dispute. If you'll point out what you think is inaccurate, I'll know what to start working with first.

If I've read the previous discussion correctly (which I may very well not have -- the formatting makes it difficult to know who's saying what), it sounds like you're disputing the idea that alchemy includes anything other than turning lead into gold. I don't really think that idea needs any citation, since it's pretty basic to the field. Citations for specific elaborations of the idea will be added as the content is written, but for now there's not much here but an outline.--Bedawyn 17:21, 1 Oct 2004 (UTC)

 * I commiserate that this page is particularly difficult to follow, particularly since Lobster interjected commentary into what I wrote, often without organization or appending a signature. Your assesment however is largely correct.  I concur with the Wikipedia Entry, however I would prefer to see citations for such claims as "Alchemical relaxation".  Additionally, the denotations were taken largely out of context.  I grant that this is a work in progress, but in its current form, even its scope itself is a contradiction:

This is an exercise in operative alchemy. ... Speculative alchemy is what you are reading.

 * It is presumed that both are exclusive, yet neither is defined. Hopefully with further revisions, the page will improve dramatically.

 * --Eibwen 19:19, 3 Oct 2004 (UTC)

TOC Reorganization
Okay, here's a possible second draft for the structure. I've fixed the header heirarchy, added a few sections, and rearranged a few others. I haven't deleted any, although I think a few of them should be deleted. Proponents and Achievements, for instance, are obviously very important types of information, but I do think they're types of information rather than topics on their own. I'd suggest deleting them as sections and instead incorporating the material into the relevant history or science sections. Newton, for instance, would go under the Western section. I didn't know what you were thinking of doing with Media and Language, so I didn't try putting them anywhere. The "As Above, So Below" concept needs to be included, but I wasn't sure whether to give it a section of its own or to thread it in throughout the History/Significance and Theory sections. Maybe a subsection within Theory? Except my own feeling is that it's important enough it needs to be introduced sooner. Maybe mentioned in passing in the introduction and/or the relevant history portions, and described fully as a subsection under Theory?--Bedawyn 23:41, 1 Oct 2004 (UTC)

 * All your ideas are fine with me - I like the idea of the planets and suggest adding the twelve types of Man Lobster 17:43, 2 Oct 2004 (UTC)

 * I'll have to leave that to you, as I'm not sure what they are. Unless you mean the Zodiac? I've actually never studied alchemy per se, just picked up bits of it as it overlaps other areas I was studying (although there is quite a bit of overlap). This book will be a good excuse for me to finally start studying it!--Bedawyn 19:15, 2 Oct 2004 (UTC)

First of all my apologies for not using my signature properly - still learning. The 12 types of Man (the use of the word Man is similar to the use of Sir to denote seniority when applied to women - and is a referral to a time of greater ignorance regarding the potential of women) So it might be more politically correct to use some other term. Alchemy is not a time or fashion centered study however. If you are interested in developing this part of the book then I suggest splitting the 12 types into the 4 elements. Then think of it is a system of balancing. If you do it in this way a horoscope becomes a quite profound form of psychological profiling (forget the stars for now). 82.69.58.117 01:06, 21 Oct 2004 (UTC)

Excelent re organisation - the work needs to be fleshed out to make 'Adam Kadmon' the primal man come to life Lobster 08:46, 8 Dec 2004 (UTC)

Appropriate Bookshelf
What on earth is this doing in the science section? There's no possible explanation for that. I personally don't see the utility of this "textbook" at all, but if people want to write it on Wikibooks that's fine as long as it's not in the science section. And for those who suggest that alchemy being a precedent to chemistry makes it a science, religion and witchcraft and magic etc. played a similar role, but I think you'll agree there should not be a science textbook on religion, witchcraft or magic (if you disagree, you're even more strangely deluded than I thought). --24.103.207.38 22:03, 23 Oct 2004 (UTC)

 * So, the ptoblem with this matter is the classification in the Science section. It is not, in the frame of modern definition of scientific methodology. But it is an old and comprehensive body of knowledge, a very interesting expression of human colective psyche, as it used to express when mankind was not so tied to matter and to causal thought to had become unable to feel the flow of energy among living beings and other things.
 * Alchemy is a major basis of C.G.Jung's work. See his Psychology and alchemy, Mysterium conjuncionis, etc. Deleting this book is medieval censorship. --Ligia 02:32, 5 Dec 2004 (UTC)

Alchemical principles are used in wiki creation, scientific method, medicine preparation, architecture, art and gastronomy. It has long engaged at the highest level of human endeavour whilst the unintiated say Gu? - just like when we first showed them metal as superior to flint Lobster 17:07, 5 Dec 2004 (UTC)

For some reason this is under "Chemistry" in the Natural Sciences section of Wikibooks. Surely, we can think of a better category?

 * The Alchemy book has been removed from the chemistry bookshelf and placed on the miscellaneous bookshelf. Perhaps if texts on astrology, witchcraft, karma, and the like are written, it can get a more conspicuous position on a such a new-age/mysticism bookshelf. Zolot

Neo Alchemy
Alchemy is not a static science and it is borne in fire and flaming - in the furnace. I wish everyone success in cooking up the magic of a book. It may end in flames. It may result in a great future. Lobster 08:49, 8 Dec 2004 (UTC)

I'm sorry, but this is a pretty general book. There's a fine line between sciences and new age hippies' books.

title: Talk:Alchemy


text:
Cookbook talk:Easy Scrambled Eggs

The recipe should mention that the amounts of ingredients needn't be propotional. For example, some people may prefer many eggs but little salt.

I am unsure as to the listing of Canola oil as an ingredient. If it enhances the flavor, fine -- however if it is merely used to prevent the eggs from sticking to the pan, it should be removed from the list. The ONLY necessary ingredient that I am aware of is the eggs themselves.

Perhaps mention that 4 eggs is a typical serving -- or whatever the case may be.

--Eibwen 20:13, 25 Sep 2004 (UTC)

 * Oil does taste good. AlbertCahalan 16:11, 8 October 2005 (UTC)

--User:Anonymous 04:02, 7 December 2005 (UTC) Changed ingredients to allow for different sizes, seasoning to taste (orig recipe had WAY too much salt, I think it was measure in tablespoons), and different fats.

Re-wrote instuctions, but left others because there is more than one way to do it. The new instructions are clearer and more thorough.

Shaped Scrambled Eggs?
Does anyone know how to make shaped scrambled eggs? Like what you would get if you were at a restaurant and ordered a sausage egg and cheese biscuit?

I once bought a ring that was supposed to this, but it didn't work. So please don't edit this if you're only guessing. I was hoping someone could add more depth to this article by adding different ways scrambled eggs could be made.MagnoliaSouth 12:29, 10 June 2006 (UTC)

title: Cookbook talk:Easy Scrambled Eggs


text:
Cookbook talk:Butter

The page Cookbook:Butter already exists. Moreover, the appropriate section for general questions is the Study help desk. Your question has been answered there.

--Eibwen 21:01, 25 Sep 2004 (UTC)

---

The text of this module, or a version in the page history, was taken from the Wikipedia article Butter. The authors of that page at the time the text was copied are listed below:

 * (cur) (last) . . 20:02, 26 Feb 2004 . . 18.24.0.120 (Cultured versus sweet butter. Xrefs.)
 * (cur) (last) . . M 00:33, 19 Feb 2004 . . Fuzheado (Reverted edits by 162.83.176.100 to last version by Angela)
 * (cur) (last) . . 00:32, 19 Feb 2004 . . 162.83.176.100 (Helping the things.)
 * (cur) (last) . . M 12:04, 19 Dec 2003 . . Angela
 * (cur) (last) . . M 03:36, 1 Dec 2003 . . Tarquin (fr)
 * (cur) (last) . . M 09:16, 12 Nov 2003 . . Infrogmation
 * (cur) (last) . . M 09:10, 12 Nov 2003 . . Infrogmation
 * (cur) (last) . . 09:07, 12 Nov 2003 . . Infrogmation (traditional butter making photo and explanation)
 * (cur) (last) . . M 06:01, 28 Oct 2003 . . Carbuncle (+ja:)
 * (cur) (last) . . M 16:40, 11 Oct 2003 . . Angela (http://wiktionary.org/wiki/Churn)
 * (cur) (last) . . 13:58, 29 Jul 2003 . . Den fjättrade ankan
 * (cur) (last) . . 17:21, 21 May 2003 . . AxelBoldt (fat content; butter milk)
 * (cur) (last) . . M 17:17, 21 May 2003 . . AxelBoldt (links)
 * (cur) (last) . . M 07:59, 20 Apr 2003 . . Youandme (+pl:)
 * (cur) (last) . . 05:39, 18 Apr 2003 . . Montrealais
 * (cur) (last) . . M 03:02, 9 Nov 2002 . . Maveric149 (de:w:Butter)
 * (cur) (last) . . 20:43, 1 Nov 2002 . . 62.57.117.20
 * (cur) (last) . . M 05:48, 8 Oct 2002 . . Andre Engels (nl:)
 * (cur) (last) . . M 02:17, 28 Mar 2002 . . -- April (format)
 * (cur) (last) . . 01:49, 28 Mar 2002 . . -- April (Work Household Cyc text into useable history)
 * (cur) (last) . . M 04:24, 27 Mar 2002 . . Brion VIBBER (fixed degree signs)
 * (cur) (last) . . 03:48, 27 Mar 2002 . . Lee Daniel Crocker
 * (cur) (last) . . 03:25, 27 Mar 2002 . . The Cunctator (*A brief definition)
 * (cur) (last) . . 03:24, 27 Mar 2002 . . -- April (more household cyc text. This one's really outdated - churning, for heaven's sake...)
 * (cur) (last) . . M 01:32, 27 Mar 2002 . . 62.98.140.140

Butter was the featured ingredient on the main Cookbook page from April 28, 2004 - May 8, 2004.

title: Cookbook talk:Butter


text:
Talk:Embedded Systems/8051 Microcontroller/Internal Architecture

The phrase "NEXT:" should be excised from the topic. The title of wiki links can be specified:

[[ Page | Title of link ]]

which renders:

Title of link

Moreover, the title should reflect that the internal architecture is of a particular chip.

--Eibwen 21:10, 25 Sep 2004 (UTC)


text:
Talk:LPI Linux Certification/LPIC1 Exam 101/GNU & Unix Commands

Depending on the nature of the section on vi, you may want to merely link to vi


text:
Talk:PHP Programming/html output

This may be slightly beyond the scope of the section, but there are additional methods (and probably several others):

echo 'Link'. "\n";

Yet for a PHP page intended for viewing on the internet (as opposed to console PHP scripts), the simplest approach is likely:

?>Link<?

Granted this precludes the use of variables, but if there aren't any variables to include, why use PHP for its own sake?

--Eibwen 22:31, 25 Sep 2004 (UTC)

I added the section on breaking PHP scripts for output, I've been meaning to for a while. Thanks for your input. --Spoom 06:29, 6 Oct 2004 (UTC)

title: Talk:PHP Programming/html output


text:
World History/The Renaissance in Europe

Fall of the Byzantines and Rise of the Ottomans
When in 1453, the Ottoman Empire captured Constantinople, and renamed it Istanbul, Rome was finally declared crushed. It began to fall in all areas of life, and then fell altogether. Meanwhile, the most successful Ottoman ghazi came to power(1248-1326?) and began to build the Ottoman Empire. Ostman was a firm believer of Islam, and treated all his captured people with respect, and allowed them to worship whom they wished.

title: World History/The Renaissance in Europe


text:
Radiation Oncology/Cancer Syndromes

Cancer Syndromes

 * Syndromes You Should Know
 * Ataxia-Telangiectasia
 * Ataxia-Telangiectasia-Like Disorder (ATLD)
 * Nijmegen Breakage Syndrome (NBS)
 * Nijmegen Breakage Syndrome-Like Disorder (NBSLD)
 * Bloom Syndrome
 * Fanconi Anemia
 * Xeroderma pigmentosum
 * Cockayne Syndrome
 * Hereditary Non-Polyposis Colorectal Cancer (HNPCC) / Lynch Syndrome
 * Familial adenomatous polyposis (FAP) / Gardner Syndrome
 * Nevoid Basal Cell Carcinoma Syndrome (NBCCS) / Gorlin Syndrome
 * PTEN Hamartoma Tumor Syndrome (PHTS)
 * Cowden syndrome (part of PHTS)
 * Li-Fraumeni Syndrome
 * Von Hippel-Lindau Disease
 * Neurofibromatosis Type 1 (NF-1)
 * Wiskott-Aldrich Syndrome

 * MD Anderson; 2009 PMID 19616740 -- "Clinical radiation sensitivity with DNA repair disorders: an overview." (Pollard JM, Int J Radiat Oncol Biol Phys. 2009 Aug 1;74(5):1323-31.)

Paraneoplastic Syndromes

 * Syndrome of Inappropriate Antidiuretic Hormone
 * Myasthenia Gravis

title: Radiation Oncology/Cancer Syndromes


text:
Conlang/Intermediate/History/Common sound changes

As time progresses and a language is often used, sounds start to change; different phonemes are used. The words get "smoothed" like gravel at a beach or in a desert. After centuries the stones will be smooth. Sound changes, as they're called, are a major driving force of language change.

Sound changes are born every time we speak. People rarely say any word perfectly; perhaps your <t> was a little too far forward, or your <u> wasn't rounded as much as it normally would be. Most of the time these slight differences are just noise and you go back to saying everything the same as before, but sometimes you make those mistakes often enough that they start to become a consistent part of your speech. Anyone who respects or admires you — even if it's just your group of friends — will start to subconsciously copy the way that you speak and that sound change will begin to spread.

Sound change is nigh unstoppable. If you write two novels in the same setting in different periods of time using the same conlang, it's quite likely some sound changes will have happened, so you'll want to implement them.

Sound change also has no memory. If at a certain point in time there are some sounds X in words, they all will change to Y even if some of them were W a few centuries ago while some have been X since the beginning of the language.

Although it seems like sound change happens regardless of grammar, this is not necessarily true. As an example, some varieties of Brazilian Portuguese delete final in verbs, but not in nouns or nominalized verbs. The infinitive "poder" (can) is usually pronounced, but as a noun, "poder" (power) is pronounced , even colloquially. Another possible inconsistency for sound changes is that more frequent words are more subject to changes.

In the case that two words would be pronounced the same if a certain sound change happens, one of the following things can happen:

 * Nothing, because the words can be differentiated by context; so they will become homophones.

 * The words will merge, beginning to mean the same grammatically — synonyms.

 * The word to be changed will refuse to change.

 * People will stop using one or the other word, replacing it with another construct.

Common Sound Changes
Some kinds of sound changes are more common than others. Let's take a look at the most common ones.

Assimilation
Assimilation is by far the most important sound change. Assimilation is when a sound changes to become more similar to the surrounding sounds. A consonant may change to match the place or type of articulation of an adjoining consonant.

 * In English, // often becomes [] (labiodental) before //, like in <infant>.

 * The word is an example. It comes from adding <ad-> onto <similate>. The // assimilates to //.

Lenition
Lenition is the "weakening" of sounds. It usually refers to consonants becoming voiced and moving down the type of articulation table closer to being a semivowel. It also refers to sounds that disappear altogether. Lenition is especially common intervocalically (between two vowels).

 * Examples:
 * // » []
 * // » []
 * // » []

 * In some varieties of English, // and // can become [] word-internally.

Palatalization
Palatalization is the shifting of a consonant towards the palate. This is a common type of assimilation. Consonants can palatalize before or after a front vowel ([], []) or a palatal consonant ([]), perhaps ending up as an affricate or fricative.

 * Examples:
 * // » []
 * // » []
 * // » []
 * // » []
 * // » []

 * In English, pronunciation of the -tion suffix as // is the result of palatalization of a former //.

 * In Japanese, the pronunciation of  as //,  as //,  as //, and  as // is the result of palatalization.

Velarization
Velarization is a secondary articulation of a consonant where the back of the tongue is raised towards the velum. In some languages, such as Russian and Irish, velarized consonants often contrast with palatalized consonants.

 * In some varieties of English, when // is found in the syllable coda position, it is velarized (e.g. as //). When // is found in the syllable onset position it is non-velaried (e.g. as //).

Monophthongization
Monophthongization is the simplification of a diphthong (or triphthong) down to a single vowel. This feature was very common in Old French and Ancient Greek, leading some the diphthongs of these languages to be monophthongized. For instance, the French <ai> and <eau> are now pronounced [] and []; in Modern Greek, the combinations <ει> and <οι> are pronounced [].

 * In Australian English, the diphthong // (as in <air>) is often pronounced [].

 * In some American English dialects, the diphthong // (as in <eye>) is pronounced [].

Nasalization
Vowels next to nasal consonants very often become nasal themselves. This is a type of assimilation. If a nasal consonant disappears, the mark it left on the vowel may remain, causing nasal vowels to become phonemic.

 * Again, this is a feature very common in the French language. Consider the word <maison>, house pronounced []. The <o> was nasalised because a nasal sound (namely //) was following.

Rhotacism
This is the change from // to a trilled //, which has occurred in various European languages. In Latin, // became // between vowels (lenition), and // then proceeded to become //. This causes alternations between // and // in some words' inflected forms: Flower is flos in the nominative singular, but floris in the genitive.

You can regularise these sounds over time. Latin did this, so that original flos and honos became flor and honor, to match their genitives floris and honoris.

Environments
Sound Changes can happen both unilaterally (in every possible location) or only in certain environments. For instance, a language may lenite a particular sound, only if it follows a particular consonant. When logging sound changes, a standardized notation is used, which looks something like this:

[x] > [y] / [z]_

In this formula, the underscore indicates where our phoneme in question would be, and it can be read as "when [x] follows [z], it becomes [y]". This basic structure can be expanded for more tricky rules. For example

[x] > [h] / #[V]_

Here we are indicating that [x] becomes [h] when following [V], where [V] is "any vowel". We have also added the hash to the second half of the equation, which indicates a word boundary (either initial or final). This means we can read this as "post-vocalic [x] becomes [h] in initial syllables only."

Choosing sound changes
The basic idea here is that when you're making your conlang you should have in your mind a parent language (or proto-language) and a child language. The proto-language is going to be a conlang just as we have been making up until this point and should not have any history to it. The child language is going to contain all the history. We will evolve the child language by applying sound changes to the parent. The child language is the result; the language that you will present to other people, or put in your novel, or whatever other reason you conlang for.

Before you begin, you may want to have some idea of the kinds of sounds that you want your child language to have. Create a rough draft of the phonology of the child language. Once you have that, you can start trying to change the phonology of the proto-language into this child draft by selecting sound changes and adding them to a list. It takes some practice to be able to do this well, so don't worry too much if the final product isn't exactly the same as your draft.

Alternatively, you can decide not to worry too much about the final product and simply select sound changes randomly. You won't have much control over what you get, but you may get something interesting.

Once you have a list of sound changes, you will want to go through the dictionary of the proto-language and apply those sound changes to every word there.

Sound change appliers
You may have noticed that applying sound changes to words is quite a tedious process. To help with this, some conlangers have written computer programs called Sound change appliers that automate much of this work for you.

The original and most famous sound change applier is the by Zompist.

Sound change appliers are powerful and useful tools, but they can have trouble with certain kinds of changes. They can get confused by any change that needs to happen in particular syllables, such as syllable-based syncope, or any change where the environment spans multiple syllables, such as umlaut.


text:
Prolog/Math, Functions and Equality

This section explains how to use math in prolog, using functions and equality.

Numbers in Prolog
Prolog, like any other programming language, has a representation for numbers. Numbers are used like constants, and represented like they are anywhere on the computer, the following are valid ways of dealing with numbers in a predicate:

a(12, 345). a(A) :- b(A, 234.3). a(345.3409857) :- b(23476.923804).

To perform mathematical operations on numbers, we will need functions. To store the result of a mathematical operation in a variable, we will need to look more closely at equality.

Functions
Until now, predicates have always represented a simple true or false. Predicate a(A, B) is true or false, depending on the values of A and B. Functions are predicates that represent a value. The sin predicate, for instance, is a function. sin(0) represents the value 0 and sin(1) represents the value 0.841471. Functions can be used anywhere a number or constant can be used, in queries, predicates and rules. For instance, if the fact p(0). is in your program, the query ?- p(sin(0)). will unify with it.

The following common mathematical functions are built in to most Prolog implementations:

(table to be completed)

Note that functions themselves cannot be evaluated. the query '''?- sin(3). ''' will fail because sin is implemented as function and not as a predicate.

One difference between functions and predicates is that the meaning (or definition) of a predicate is usually defined by you, in your program. When you use functions like sin, they've already been defined in your prolog implementation. In other words, prolog will not find the definition in your program, but in it's library of built-in predicates. It is possible to create your own functions, but that's something you will usually not need.

Equality
There are several kinds of equality, with slightly different meanings. Here we will just look at the = operator and the is operator. First, look at:

?- A is 36/5.

This query assigns the result of mathematical operation 36/5 to the variable A. So Prolog will answer:

A = 7.2

This idea may be familiar from other programming languages. The = operator, however, is very different. It doesn't solve the right-hand side, but instead keeps it as a formula. So you get this:

?- A = 36/5. A = 36/5

Instead of assigning the result of the operation to the variable A, prolog assigns the operation to A, without evaluating it.

You can see the same thing with queries. If you ask

?- (31 is (36-5)).

You'll get "Yes", because the (36-5) is evaluated (solved). But if you ask

?- (31 = (36-5)).

You'll get "No", because Prolog will compare a number (31) to a formula (36-5), rather than to the result of solving the formula.

The is operator is meant specifically for mathematical functions. The left argument has to be a variable and the right argument has to be a mathematical function with all variables instantiated. The = operator is used for unification of variables and can be used with any two arguments (although it will fail if the two arguments aren't the same and can't be made the same by instantiating variables a certain way).

Prolog knows many other ways of comparing two terms or instantiating variables, but for now, these two will suffice. When working with functions, we will almost always use the is operator.

Math
Now that we know about functions and equality, we can start programming with math.

plus(A, B, C) :- C is A + B.

This predicate adds two numbers (A and B), and unifies the result with C. The following program is somewhat more complex.

fac(0,1). fac(A,B) :- A > 0, Ax is A - 1, fac(Ax,Bx), B is A * Bx.

This program calculates the factorial of A (A! in math notation).

It works recursively. The first rule states that the factorial of 0 is 1. The second states that the factorial of a number A greater than 0 is the factorial of A-1 times A.

Exercises
(1) What will prolog answer to the following queries (on an empty database)? Try to think of the answer yourself, and then use a prolog compiler to verify it.
 * ?- X = 1 + 2 + 3.
 * ?- X is 100/10.
 * ?- X is (14 + 16)/3, X + 3 = Y.
 * ?- X = 1000/100 + 5, Y is X.

(2) Write a predicate called sigma, such that sigma(A,B,N) is true when N=A+(A+1)+(A+2)+...+(B-2)+(B-1)+B. In other words, $$\sum_{i=A}^B i = N$$. You may assume that A and B are integers with B>A. Test your predicate with queries such as:

?- sigma(4,9,X). X = 39 ; fail. ?- sigma(-7,-2,X). X = -27 ; fail. ?- sigma(-5,5,X). X = 0 ; fail.

(3) The factorial program shown at the end of this chapter sins against one of the guidelines of using recursive rules. In the second rule:

fac(A,B) :- A > 0, Ax is A - 1, fac(Ax,Bx), B is A * Bx.

The recursive part is not the last predicate in the rule.

 * Show how prolog evaluates the query ?- fac(3, X). and explain why the program is set up like this.
 * Explain why the line A > 0 is necessary. What would prolog do after it had found an answer, if the line was missing?

Answers to Exercises
(1) ?- X = 1 + 2 + 3. X = 1 + 2 + 3. ?- X is 100/10. X = 10.

?- X is (14 + 16)/3, X + 3 = Y.     X = 10. Y = 10 + 3.

?- X = 1000/100 + 5, Y is X.     X = Y, Y = 15.

(2) As usual, there is more than one way to solve this problem. Here's one way which uses recursion in a similar way to the factorial predicate.

sigma(A,A,A). sigma(A,B,N) :- B>A, %What do you think would happen if you removed this line? Try it. Why does this happen? A1 is A+1, sigma(A1,B,N1), N is A+N1.

Tail Recursive way: sigma(A,B,N):- add_1(A,B, A, N).

add_1(B,B,N,N).

add_1(A,B,Count,N):- B > A,   A1 is A + 1, Count1 is Count + A1, add_1(A1, B, Count1, N).

Prev:Lists Next:Putting it Together

Prolog/Matemática

title: Prolog/Math, Functions and Equality


text:
Talk:Information Ecology/RGB Matrix

what the hell is all this hippie bullshit? what does it have to do with ANYTHING?

title: Talk:Information Ecology/RGB Matrix


text:
Management Strategy/Five Forces

Michael Porter, one of the leading researchers in the field of business and a professor at Harvard Business School, has identified five key forces which affect the strategy of any industry. These forces are:
 * 1) Threat of New Entrants
 * 2) Threat of Substitutes
 * 3) Industry Competition
 * 4) Bargaining Power of Suppliers
 * 5) Bargaining Power of Buyers

Managers use the Five Forces model to help identify opportunities or evaluate decisions in the context of the environment. Often, the Five Forces are mapped against a SWOT analysis to develop a corporate strategy.

To complete a Five Forces analysis, it is often best to build a grid on a piece of paper and label each section--keeping Industry Competition separate. Fill-in each section and to develop a view of the industry. Then, think about if the industry is truly competitive or if the industry is a monopoly or oligopoly. What makes your company able to compete in this environment?

title: Management Strategy/Five Forces


text:
Cookbook talk:Rice Recipes

Id like to know how to make really good egg fried rice :)

--

Rice can be boiled with coconut milk, can't it? I'd like to know how. :) Evktalo 16:35, 22 August 2005 (UTC)

title: Cookbook talk:Rice Recipes


text:
User talk:Oronmornen

Link a mi página: User talk:Alex beta

cursiva

negrita

Link a mi página (con el nombre del link cambiado): Pincha aquí para ir a mi página

Link externo a Wikiversity: google

Nuevo Apartado
Este es un nuevo apartado.

¡Ánimo, Óron!
Vemos que ni te has molestado en quitar los comentarios que te escribí más arriba. Esperamos impacientes la fundación del departamento de física de la universidad. (Alex beta 21:00, 8 Oct 2004 (UTC))

title: User talk:Oronmornen


text:
Organic Chemistry/Isocyanate

Organic isocyanates have the formula R-N=C=O where R can be either alkyl or aryl. They can be solids or liquids. Isocyanates are generally toxic and must be handled with great care, especially the more volatile isocyanates where inhalation is a primary route of exposure.

Isocyanates are usually produced by reacting an amine with phosgene (COCl2):

They are very reactive molecules, reacting with nucleophiles such as water, alcohols or amines. The reactions involve attack at the carbon of the isocyanate in a manner similar to that for carboxylic acid derivates such as esters or anhydrides.

Water reacts with isocyantes to give a carbamic acid. This reaction is catalyzed by tertiary amines. Carbamic acids are unstable and decompose to carbon dioxide and an amine, R-NH2

Alcohols react with isocyanates to give carbamates which are also known as urethanes. This reaction is catalyzed by tertiary amines or salts of metals such as tin, iron and mercury.

Primary and secondary amines react with isocyanates to give substituted ureas.

R' and R" can be H, alkyl or aryl

Isocyanates themselves to give dimers and trimers.

title: Organic Chemistry/Isocyanate


text:
Talk:Internet Technologies/Domain names

While I applaud your citation of various RFCs, please use the IETF RFC Repository.

--Eibwen 05:46, 27 Sep 2004 (UTC)

title: Talk:Internet Technologies/Domain names


text:
Talk:Statistics/Summary/Variance

Hi! I came here looking for an explanation of why the differences are squared when calculating standard deviation. The text gives the same explanation as many other texts on statistics I've seen: to get rid of the minus signs. However, if this was the whole story, it would be sufficient to take the absolute value of each difference, and divide by N to get what I think is called "average deviation".

So what makes standard deviation better than average deviation?

Greetings, Simon

 * I'm not sure I would say that the standard deviation is "better" or "worse" than the mean deviation. Most of the equations are based around the standard deviation, and so that is what we use.  This is just a guess, but since the advent of computers it may also have to do with subtraction of nearly equal numbers being inaccurate and the absolute value in general can be non-useful to work with if you are trying to keep a "running estimate" of the deviation estimate.

 * For example, with the standard deviation, we only need to calculate the sum, the sum of squares, and the number of entities to find the variance (and from there, the standard deviation) for any number of values.  This computational method is more accurate on a computer (since it avoids subtraction of nearly equal numbers), and mathematically identical to the "standard method" used.

 * With the mean deviation, I don't know of any cute ways of rewriting it to avoid that step, so every time a number is added the mean would have to be recalculated, along with each differential along the way. Thus, for the list of numbers {5, 4, 3, 2, 1} we only have to store the numbers 55 (the sum of squares), 15 (the sum), and 5 (the number of entries.  If we add the number 6 to the list, we can calculate 91, 21, and 6 without having to go back to the original list of numbers.  This is much simpler than for the mean deviation, where we need to go back and calculate each individual differential ({2, 1, 0, -1, -2} in the first case and {1.5, 0.5, -0.5, -1.5, -2.5} in the second).

 * Does that make any sense? --Llywelyn 04:17, 28 Sep 2004 (UTC)

The standard deviation is a good estimate of scale when the data are normally distributed. In practice, it is common for data to be non-normal. They can often be transformed to something resembling normality (often, taking logs is a good choice). However, even after transformation it is common that the data will be heavy tailed and subject to outliers.

In these circumstances, the standard deviation is not "better" than the mean absolute deviation. In fact, it is much less efficient (i.e. its variance is higher). There are, however, even better estimates of scale than the mean absolute deviation. One is the mad (median absolute deviation).

This issue is used by Huber (1981) as an example that suggests robust methods over classical methods (Huber's book has recently been republished in paperback format and is more affordable than previously). I believe that Tukey also drew attention to the shortcoming of the standard deviation in this respect as far back as 1960s. This article on robust statistics might be of interest.

P. J. Huber, Robust Statistics, Wiley, 1981
 * Hey that's interesting to hear, because I just posted a comment on the article saying that the "get rid of minus" argument is tosh - just that I had assumed there would be sound reasonings otherwise. I'm writing a statistics test soon, and so I'm sure I'll be using the conventional method there, but may look into this later on. Sean Heron (talk) 20:29, 11 July 2009 (UTC)

title: Talk:Statistics/Summary/Variance


text:
User:Sascham

Sascha Meissner 505 Riverbend Parkway Apartment 225 Athens, GA 30605 USA

Tel#: 706-351-0602 Email: sascham@uga.edu MSN: demeuse5@hotmail.com AOL: same08@aol.com --

title: User:Sascham