Calcium (Ca) has 24 isotopes, from 34Ca to 57Ca. There are five stable isotopes (40Ca, 42Ca, 43Ca, 44Ca and 46Ca), plus one isotope (48Ca) with such a long half-life that for all practical purposes it can be considered stable. The most abundant isotope, 40Ca, as well as the rare 46Ca, are theoretically unstable on energetic grounds, but their decay has not been observed. Calcium also has a cosmogenic isotope, radioactive41Ca, which has a half-life of 102,000 years. Unlike cosmogenic isotopes that are produced in the atmosphere, 41Ca is produced by neutron activation of 40Ca. Most of its production is in the upper metre or so of the soil column, where the cosmogenic neutron flux is still sufficiently strong. 41Ca has received much attention in stellar studies because it decays to 41K, a critical indicator of solar-system anomalies. The most stable artificial radioisotope is 45Ca, with a half-life of 163 days.
All other isotopes have half-lives of 163 days or less, most under a minute. The least stable is 34Ca with a half-life shorter than 35 nanoseconds.
Calcium-48 is a scarce isotope of calcium containing 20 protons and 28 neutrons. It makes up 0.187% of natural calcium by mole fraction. Although it is unusually neutron-rich for such a light nucleus, the only radioactive decay pathway open to it is the extremely rare process of double beta decay. Its half-life is about 4.3×1019years, so for all practical purposes it can be treated as stable. One factor contributing to this unusual stability is that 20 and 28 are both magic numbers, making 48Ca a "doubly magic" nucleus.
Since 48Ca is both stable and neutron-rich, it is a valuable starting material for the production of new nuclei in particle accelerators, both by fragmentation and by fusion reactions with other nuclei, for example in the recent production of ununoctium. Heavier nuclei generally require a greater fraction of neutrons for maximum stability, so neutron-rich starting materials are necessary.
48Ca is the lightest nucleus known to undergo double beta decay and the only one simple enough to be analyzed with the sdnuclear shell model. It also releases more energy (4.27MeV) than any other double beta decay candidate. These properties make it an interesting probe of nuclear structure models and a promising candidate in the ongoing search for neutrinoless double beta decay.
Foster's Home for Imaginary Friends is an American animated television series created by Craig McCracken for Cartoon Network Studios. The series, set in a world in which imaginary friends coexist with humans, centers on an eight-year-old boy, Mac, who is pressured by his mother to abandon his imaginary friend, Bloo. After Mac discovers an orphanage dedicated to housing abandoned imaginary friends, Bloo moves into the home and is kept from adoption so long as Mac visits him daily. The episodes revolve around Mac and Bloo as they interact with other imaginary friends and house staff and live out their day-to-day adventures, often getting caught up in various predicaments.
McCracken conceived the series after adopting two dogs from an animal shelter and applying the concept to imaginary friends. The show first premiered on Cartoon Network on August 13, 2004, as a 90-minute television film. On August 20, it began its normal run of twenty-to-thirty-minute episodes on Fridays, at 7 pm. The series finished its run on May 3, 2009, with a total of six seasons and seventy-nine episodes. McCracken left Cartoon Network shortly after the series ended.
Mac was born Mckinley Phipps in New Orleans, Louisiana. He started his music career as a kid rapper in the year 1990. At 13 years old he made his solo debut album under the name of "Lil Mac", called The Lyrical Midget. The album was one of the earliest commercial hip-hop albums to come out of New Orleans, and featured some production from New Orleans producer Mannie Fresh. It was not very successful though Lil Mac would not be heard from for another 7 years.
Late 1990s: No Limit Records, Shell Shocked, and World War III
Charlie is a former co-owner at Paddy's and a childhood friend of Mac and Dennis. Frank is his roommate and possible biological father. Charlie is the janitor at the pub, and an illiterate, alcoholic and vapors huffer, who suffers from deep psychological problems, and has anger management issues, and often screams to get his point across. He lives in squalor. Charlie's intentions are often pure, but his plans are almost always foiled. He is played by Charlie Day.
Ronald "Mac" McDonald
Ronald "Mac" McDonald is Charlie Kelly's childhood friend and Dennis's high school friend and later roommate. He is a co-owner of Paddy's and its bouncer. He brags about his incredible hand-to-hand combat skills, strength, and general athletic ability though it is quite obvious he lacks any real skill or even a proper sense of balance. His full name is revealed to be Ronald McDonald in the seventh season episode "The High School Reunion", though his last name involving "Mac" had been established since the introduction of his father. Mac and Dennis share an odd relationship that is highlighted in the later seasons. It is obvious to everyone on the show's universe except Mac that he is gay, and that he is only in denial about it because of his unbending pre-Vatican II Catholicism. He is played by Rob McElhenney.