Deformations of the Boson sp(4,R)sp(4,R) Representation and its Subalgebras

The boson representation of the sp(4,R) algebra and two distinct deformations of it, are considered, as well as the compact and noncompact subalgebras of each. The initial as well as the deformed representations act in the same Fock space. One of the deformed representation is based on the standard q-deformation of the boson creation and annihilation operators. The subalgebras of sp(4,R) (compact u(2) and three representations of the noncompact u(1,1) are also deformed and are contained in this deformed algebra. They are reducible in the action spaces of sp(4,R) and decompose into irreducible representations. The other deformed representation, is realized by means of a transformation of the q-deformed bosons into q-tensors (spinor-like) with respect to the standard deformed su(2). All of its generators are deformed and have expressions in terms of tensor products of spinor-like operators. In this case, an other deformation of su(2) appears in a natural way as a subalgebra and can be interpreted as a deformation of the angular momentum algebra so(3). Its representation is reducible and decomposes into irreducible ones that yields a complete description of the same

Sliderule-like property of Wigner's little groups and cyclic S-matrices for multilayer optics

It is noted that two-by-two S-matrices in multilayer optics can be represented by the Sp(2) group whose algebraic property is the same as the group of Lorentz transformations applicable to two space-like and one time-like dimensions. It is noted also that Wigner's little groups have a sliderule-like property which allows us to perform multiplications by additions. It is shown that these two mathematical properties lead to a cyclic representation of the S-matrix for multilayer optics, as in the case of ABCD matrices for laser cavities. It is therefore possible to write the N-layer S-matrix as a multiplication of the N single-layer S-matrices resulting in the same mathematical expression with one of the parameters multiplied by N. In addition, it is noted, as in the case of lens optics, multilayer optics can serve as an analogue computer for the contraction of Wigner's little groups for internal space-time symmetries of relativistic particles.Comment: RevTex 13 pages, Secs. IV and V revised and expande

Radiation Budget Instrument On-Board Solar Calibration Target Concept and Operation

The Radiation Budget Instrument (RBI) on-board Solar Calibration Target (SCT) concept and operation are presented in this paper. The SCT used during solar calibration of RBI is based on reflection properties of sintered Polytetrafluoroethylene (PTFE), an extremely stable, near perfect, Lambertian diffuser. The SCT incorporates three identical space grade sintered PTFE diffusers for on-orbit degradation monitoring. The SCT is used for calibration of the Shortwave (0.3 2.5 m) and Total (0.3 100+ m) channels of RBI. System level calibration test design and pre-flight calibration of each diffuser is also presented

Can depopulated villages benefit from the social and economic incorporation of ethnic and immigrant communities? A survey for Bulgaria

One of the greatest problems faced by rural areas in Bulgaria today is depopulation. The main research question posed in this paper is whether such depopulated regions can benefit from the social and economic integration of ethnic and immigrant communities. A survey on public opinion was conducted in two regions: one developed (Stara Zagora District), and one lagging (Vidin District). It focused on the willingness of local communities to “welcome” newcomers, to cohabit with them and their awareness of the possibility of enriching local cultures with their specific cultural traditions and experience. Results show varying tendencies, depending on the regional socio-economic level of development and degree of integration of the group. The survey directs the attention to significant social distances emerging in various regional communities between local populations, ethnic and/or immigrant communities. Conclusions reached show that ethnic and immigrant communities can be an important social and economic resource for Bulgarian villages. Nevertheless, this requires work predominantly on the structural level for providing opportunities and eliminating disadvantages, involving the introduction of improved integration and discrimination policies, legal framework and market opportunities, in order to foster better interethnic communication and trust, as an intrinsic quality of social capital, for overcoming existing barriers

Blood fibrinogen concentrations in New Zealand white rabbits during the first year of life

The aim of this study was to examine the reference range of blood plasma fibrinogen, which belongs to the group of moderate acute phase protein in rabbits. The experiment followed the dynamics of blood plasma fibrinogen (Fb) during the first year of life in 12 New Zealand White rabbits, 6 males and 6 females, starting at 1 month of age until the 7th month. It was shown that fibrinogen concentrations increased with the age. There was a statistically significant difference in Fb concentrations in rabbits at 3 (P<0.05), 6 (P<0.01) and 7 months of age (P<0.001) compared to levels obtained at 1 month of age in both genders. At ages of 1, 2 and 3 months, fibrinogen values were higher in male rabbits while in 7-month-old rabbits, plasma fibrinogen levels in females were significantly higher than those in male rabbits (P<0.01)