5,671 research outputs found
Non-classical properties and algebraic characteristics of negative binomial states in quantized radiation fields
We study the nonclassical properties and algebraic characteristics of the
negative binomial states introduced by Barnett recently. The ladder operator
formalism and displacement operator formalism of the negative binomial states
are found and the algebra involved turns out to be the SU(1,1) Lie algebra via
the generalized Holstein-Primarkoff realization. These states are essentially
Peremolov's SU(1,1) coherent states. We reveal their connection with the
geometric states and find that they are excited geometric states. As
intermediate states, they interpolate between the number states and geometric
states. We also point out that they can be recognized as the nonlinear coherent
states. Their nonclassical properties, such as sub-Poissonian distribution and
squeezing effect are discussed. The quasiprobability distributions in phase
space, namely the Q and Wigner functions, are studied in detail. We also
propose two methods of generation of the negative binomial states.Comment: 17 pages, 5 figures, Accepted in EPJ
Effect of High Se and Co Alfalfa Forage on Animal Production
Total and available selenium (Se) and cobalt (Co) concentrations are low in Chinese soils, especially those found in mainly in temperate humid sub-humid conditions in the northeast to the southwest band across China (Tan et al. 2002). The levels of Se and Co are marginally deficit in the brown soil of the Yellow River region which causes lower production level and quality in forage and crop plants. Application of Se and Co fertilizers to arable lands is essential to produce high Se and Co forages. Henan is a Province where produce high-quality grass forages are used to support dairy farming. The province is mainly spread along the Yellow River where soils are sandy and deficient in Se and Co (Lu et al. 2003). Se deficiency in forages not only limits livestock production, but also affects the quality and safety of food products (Rotruck et al. 2003). Since rabbits and dairy cows are especially sensitive to low Se levels in feed, we chose these as our test animals. The objective of this study was to analyze effect of high Se and Co alfalfa forage on animal production and feed conversion efficiency in order to establish a set of effective technical ways to solve trace element gaps of animal diets, i.e. by basal fertilization of Se and Co fertilizers in soil. This study was conducted as a series of field trials and animal experiments from 2007 to 2008
Effects of Se and Co Combined Fertilizer on Production of Alfalfa
Selenium(Se) and cobalt (Co) are important essential trace elements for forage and animal production (Yang et al. 1998, Arvy 1993). The supplementation of Se in animal diet significantly increases Se-Glutathione peroxidase (GSH-Px ) activities in the liver, testes, spermatozoa and seminal plasma (Abdelrahman et al.1998), Selenium is also a key component of a number of functional seleno-proteins. GSH-Px is the best characterized of the family of selenoproteins. In Henan Province, the fine grass and green milk production zones are mainly distributed along the riverbank of the Yellow River where soils are sandy and sterile with lower Se and Co contents (Lu et al. 2003). Deficiency of Se and Co in soils affects local forage and animal production level, as well as the qualities and securities of fodder and animal products (Rotruck et al. 2003). This experiment was carried out to determine the impacts of the application combined Se and Co on the quality of alfalfa hay
Recent progress in the asymmetric Mannich reaction
The asymmetric Mannich reaction is one of the most useful carbon-carbon bond forming reactions for the synthesis of chiral molecules containing nitrogen. The resulting β-amino carbonyl compounds are valuable synthons in the preparation of many natural products with useful biological properties. In recent years, asymmetric Mannich processes have increasingly been reported and used in a rapidly growing number of applications. This review provides an overview of the recent history of the applications of various catalytic systems in asymmetric Mannich reaction, including metal-based asymmetric organocatalysis, asymmetric organocatalysis, other chiral catalysis and no chiral catalysis systems
- …