THE WHATIS.COM WORD-OF-THE-DAY December 16, 2002 positron ______________ TODAY'S SPONSOR: VeriSign - The Value of Trust
Secure all your Web servers now - with a proven 5-part strategy. The FREE Server Security Guide shows you how to: * DEPLOY THE LATEST ENCRYPTION and authentication techniques * DELIVER TRANSPARENT PROTECTION with the strongest security without disrupting users. And more. Get your FREE Guide now: http://WhatIs.com/r/0,,8441,00.htm?freeguide ______________ TODAY'S WORD: positron See our definition with hyperlinks at http://whatis.techtarget.com/definition/0,,sid9_gci869317,00.html A positron is a particle of matter with the same mass as an electron, but opposite charge. It is a form of antimatter because when a positron encounters an electron, the two completely annihilate to yield energy. The existence of the positron was predicted in 1928 by physicist Paul Dirac, and positrons were discovered experimentally in 1932 by physicist Carl Anderson. Positrons are important in a medical technology called positron emission tomography (PET), which is especially useful in brain and nervous-system scanning. A PET scanner detects and maps the radiation produced when an ingested substance emits positrons that are annihilated by surrounding electrons. The positron is not the only known antimatter particle. The proton and the neutron have antiparticles as well, known as the anti-proton and the anti-neutron, with negative and neutral electric charges, respectively. RELATED TERMS: matter http://whatis.techtarget.com/definition/0,,sid9_gci865252,00.html antimatter http://whatis.techtarget.com/definition/0,,sid9_gci866279,00.html mass http://whatis.techtarget.com/definition/0,,sid9_gci549408,00.html electron http://whatis.techtarget.com/definition/0,,sid9_gci212046,00.html charge http://whatis.techtarget.com/definition/0,,sid9_gci840676,00.html ______________________ SELECTED LINKS: The European Organization for Nuclear Research (CERN) has a Web site devoted to antimatter. http://livefromcern.web.cern.ch/livefromcern/antimatter/ ______________________ CROSSWORD PUZZLE #7 | Computer Basics Improve your flexible thinking skills. Print out the puzzle and keep it nearby to work on throughout your day! http://whatis.techtarget.com/definition/0,,sid9_gci865741,00.html ______________________ QUIZ #32 | Securing Your Network How much do you know about network security? Take our latest quiz and find out. >> Take the quiz http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci857673,00.html ______________________ REAL-LIFE CHALLENGE #20 | Is it ever a good idea to outsource IT? Is outsourcing the IT department under a contractual basis or a per-incident agreement ever a good way to cut costs? Nan, the Director of IT for a manufacturing company must decide. Can you advise? http://whatis.discussions.techtarget.com/WebX?[EMAIL PROTECTED]@.1dcfae0e/194 ______________________________ RECENT ADDITIONS AND UPDATES [1] Java Development Kit http://searchsolaris.techtarget.com/sDefinition/0,,sid12_gci868274,00.html [2] tree network http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci868977,00.html [3] SoC testing http://whatis.techtarget.com/definition/0,,sid9_gci866453,00.html [4] single-system image http://search390.techtarget.com/sDefinition/0,,sid10_gci866451,00.html [5] automated test equipment http://searchcio.techtarget.com/sDefinition/0,,sid19_gci866407,00.html ____________________________________________________________________ ::::::::::::::::::: WHATIS.COM CONTACTS ::::::::::::::::::: LOWELL THING, Site Editor ([EMAIL PROTECTED]) ____________________________________________________________________ MARGARET ROUSE, Associate Editor ([EMAIL PROTECTED]) ___________________________________________________________________ :::::::::::::::::::: ABOUT THIS NEWSLETTER ::::::::::::::::::::: Published by TechTarget (http://www.techtarget.com) TechTarget - The Most Targeted IT Media Copyright 2002, All Rights Reserved. Unsubscribe from 'Word of the Day' - Simply Reply to this Email with REMOVE within the Body or Subject > or - Go to: http://WhatIs.techtarget.com/register - Log in to edit your profile. - Click on the link to Edit email subscriptions. - Uncheck the box next to the newsletter you wish to unsubscribe from. - When finished, click "Save Changes to My Profile."
