Synchronizing mail on two computers

I use Thunderbird on several computers and need some way to synchronize messages on different computers. Luckily there are several different ways . Written for Thunderbird but also applies to Mozilla Suite / SeaMonkey.

Other suggestions are welcome:

Fundamentals of Physics

Fundamentals of Physics is a calculus based physics textbook by David Halliday, Robert Resnick, and Jearl Walker. It is a perfect introduction into physics, and has been well-known to science and engineering students for decades as “the gold standard” of freshman-level physics texts. It explains physics in a clear way without resulting in a ‘… for dummies’ book.

The textbook covers most of the basic topics in physics: Mechanics, Waves, Thermodynamics, Electromagnetism, Optics and Special Relativity. The extended edition also contains introductions to topics such as Quantum Mechanics, Atomic Theory, Solid State Physics, Nuclear Physics and Cosmology.

iTunes U

iTunes U is a part of the iTunes Store featuring free lectures, language lessons, audiobooks, and more, that you can enjoy on your iPod, iPhone, Mac or PC. Explore over 75,000 educational audio and video files from top universities, museums and public media organizations from around the world. With iTunes U, there’s no end to what or where you can learn. Check it out in the iTunes Store

(via JK)

A lot of this material (if not all) is already available on the internet. Example the MIT audio/video courses. The great thing about iTunes U is that all of this is now accessible in one place.

Keyboard and Mouse shortcuts Firefox 3

A list of keyboard shortcuts and mouse shortcuts in Mozilla Firefox

The Free Physics Textbook

The Free Physics Textbook, probably one of the best on the internet ! Just great !

NAPP Launches Lightroom Beta Learning Centre

The National Association of Photoshop Professionals has just launched the Adobe Photoshop Lightroom 2.0 Learning Center.(via)

MIT OpenCourseWare

MIT OpenCourseWare is a free publication of course materials used at MIT. A great resource !!

How to Start Your Own Country in Four Easy Steps

With Kosovo unilaterally declaring independence and a host of wannabe states looking to follow its lead, you might be thinking it’s about time to set up your own country. You’ve picked out a flag, written a national anthem, even printed up money with your face on it. But what’s the next step? Creating a new country isn’t as easy as you think.

Joshua Keating explains how to proceed.

Decimal Time

How can you convert in excel decimal time into 12- or 24-hour notation ?

Answer: if you have the number 4.50 (=A1) and you really want 4:30 or 4:30AM use =A1/24 and format as needed. If it should be 17:00 or 5:30PM use =(A1/24)+0.5

How can you convert to decimal time ?

Answer: to get the opposite, that is a decimal time from a true time, use =A1*24 (A1 being the true time format of course in this case)

Now this is simple enough, but why is this correct ?

The answer follows from the fact that Microsoft Excel stores dates as sequential numbers known as serial values and times as decimal fractions because time is considered a portion of a day. This decimal number is a value ranging from 0 to 0.99999999, representing the times from 0:00:00 (12:00:00 A.M.) to 23:59:59 (11:59:59 P.M.). Example: 21:42:10 equals 21/24 + 42/(24*60) + 10/(24*60*60) or 0.90428241. Now if you go back to the true time 4:30, this is stored by excel as 0.1875. If you multiply this by 24, you get 4.5
To display the serial number of a particular time, you can also use the TIME worksheet function if needed.

We need to make two remarks however.

Above explanation is valid for converting time, but not always for converting dates or dates with time! Originally, Excel for Windows was based on the 1900 date system, because it enabled better compatibility with other spreadsheet programs that were designed to run under MS-DOS and Microsoft Windows, and therefore it became the default date system. Originally, Microsoft Excel for the Macintosh was based on the 1904 date system, because it enabled better compatibility with early Macintosh computers that did not support dates before January 2, 1904, and therefore it became the default date system. Or January 1, 1900 has serial value 1 and December 31, 9999 serial value 2958465 if you use the WIndows version. If you use Macintosh, than January 2, 1904 has serial value 1 and December 31, 9999 serial value 2957003. The difference between the two date systems is 1,462 days; that is, the serial value of a date in the 1900 date system is always 1,462 days greater than the serial value of the same date in the 1904 date system. So be careful if you use spreadsheets made on another system ! To solve differences when doing a copy/paste or with external referencing of 2 excel sheets based on a different date system, you need to add/substract 1462 days.

A second issue is the way excel interpretes two-digit years. 00 through 29 is interpreted as the years 2000 through 2029. For example, if you type the date 28/5/19, Excel assumes the date is May 28, 2019. 30 through 99 is interpreted as the years 1930 through 1999. For example, if you type the date 28/5/98, Excel assumes the date is May 28, 1998.
In Microsoft Windows, you can change the way two-digit years are interpreted for all Microsoft Windows programs that you have installed (or you can of course just type the correct 4-digit year):

1. Click the Start button, and then click Control Panel.
2. In Windows Vista, click Clock, Language, and Region. In Windows XP, click Date, Time, Language, and Regional Options.
3. Click Regional and Language Options.
4. In Windows Vista, in the Regional and Language Options dialog box, click the Formats tab. In Windows XP, in the Regional and Language Options dialog box, click the Regional Options tab.
5. In Windows Vista, click Customize this format. In Windows XP, click Customize.
6. Click the Date tab.
7. In the When a two-digit year is entered, interpret it as a year between box, change the upper limit for the century. As you change the upper-limit year, the lower-limit year automatically changes.

Update: perhaps I will post some more of these simple tutorials in the future as not everyone is looking for ‘advanced’ tutorials.

Firefox and PDF

Recently my Firefox browser hangs when I’m trying to open a pdf file in the browser. The only solution I found till now is to disable the browser plugin and force pdf links to open with Acrobat outside of the browser.

How-to for Firefox 2: Go to “Tools”, “Options” and select “Content”. Next to “File Types” click the “Manage…” button. Select “PDF” from the list of extensions, click the “Change Action” button and change the action to “Open them with the Default Application”.

When you want to open a pdf link in your Firefox browser, Firefox will open now a download window, download the pdf file and open it with Acrobat.

This is not the ideal solution for me as I would like the pdf links to open in a new tab inside the browser, but the above solution works fine too (and quite fast). I wonder if there is another solution to this issue.