Fowl cholera immunization in turkeys. II. Use of experimental epornitic method to study vaccine efficacy in flocks of turkeys.
Groups of turkeys were challenged with Pasteurella multocida (P-1059) by the contact method. In this method, turkeys are artificially infected by the intramuscular injection of P. multocida organisms and are then introduced into the test group. The death patterns resulting from this contact method of challenge are either normally distributed or skewed to the right.
Fowl cholera in turkeys--the efficacy of adjuvant bacterins.
Ever since the production of the classical attenuated fowl cholera vaccine by Pasteur, many attempts have been made to prevent outbreaks of fowl cholera in chickens. His method could not be duplicated successfully, however, and a search for a more dependable method in controlling the disease effectively has been conducted since the early 1920's. The effectiveness of earlier aqueous avirulent vaccines (7) and bacterins (13) has always been variable (8,19,9,10). Carter (2) compared the immune response in mice to bacterins made from broth cultures and chicken embryo vaccines made from Pasteurella multocida, type A. Chicken embryo vaccine was much superior to broth-derived bacterin in immunizing value. Bierer et al. (1) described a phenol-killed autogenous bacterin which afforded some protection to turkeys in an infected flock. The challenge, however, was carried out within 20 days of vaccination.
Ocean thermal energy conversion: The promise of a clean future
Due to the world's heavy dependence on fossil fuels for electricity, pollution and global warming is on the rise. However, numerous countries are still relying on diesel generators as their main source of energy. There is a lack of practical alternative energy source that can meet the global energy demand without posing any threat to the natural environment. Ocean Thermal Energy Conversion (OTEC) is a concept that has the potential to address this growing issue. It is basically a mechanism that exploits the temperature difference between warm surface seawater and cold deep ocean water, to produce electricity. Although OTEC has a low energy density, the thermal energy in the ocean is vastly abundant. OTEC development has been dormant for a long time since it was first proposed in 1881. However, it has now regained recognition worldwide as a realistic solution to our world energy issue. Instead of having a great potential for power generation, it also carries the ability to produce high value products from the large volume of Deep Sea Water (DSW) that can be released as byproducts of OTEC plant operation. These products can hold a very profitable place in industries such as pharmaceutical, food, cosmetics and mineral water production. Further research on ocean current and DSW properties can someday lead to the commercial used of OTEC. This paper is a review of the basic concept, present status and future prospects of OTEC around the world.