440 research outputs found
Vector coherent state theory of the generic representations of so(5) in an so(3) basis
For applications of group theory in quantum mechanics, one generally needs
explicit matrix representations of the spectrum generating algebras that arise
in bases that reduce the symmetry group of some Hamiltonian of interest. Here
we use vector coherent state techniques to develop an algorithm for
constructing the matrices for arbitrary finite-dimensional irreps of the SO(5)
Lie algebra in an SO(3) basis. The SO(3) subgroup of SO(5) is defined by
regarding SO(5) as linear transformations of the five-dimensional space of an
SO(3) irrep of angular momentum two. A need for such irreps arises in the
nuclear collective model of quadrupole vibrations and rotations. The algorithm
has been implemented in MAPLE, and some tables of results are presented.Comment: 20 pages, uses multirow.sty, submitted to J. Math. Phy
Coherent state triplets and their inner products
It is shown that if H is a Hilbert space for a representation of a group G,
then there are triplets of spaces F_H, H, F^H, in which F^H is a space of
coherent state or vector coherent state wave functions and F_H is its dual
relative to a conveniently defined measure. It is shown also that there is a
sequence of maps F_H -> H -> F^H which facilitates the construction of the
corresponding inner products. After completion if necessary, the F_H, H, and
F^H, become isomorphic Hilbert spaces. It is shown that the inner product for H
is often easier to evaluate in F_H than F^H. Thus, we obtain integral
expressions for the inner products of coherent state and vector coherent state
representations. These expressions are equivalent to the algebraic expressions
of K-matrix theory, but they are frequently more efficient to apply. The
construction is illustrated by many examples.Comment: 33 pages, RevTex (Latex2.09) This paper is withdrawn because it
contained errors that are being correcte
Early cadmium-induced effects on reactive oxygen species production, cell viability and membrane electrical potential in grapevine roots
Cadmium (Cd) is one of the most worldwide concerned metal pollutants. It is able to induce reactive oxygen species production through indirect mechanisms causing oxidative stress. Vitis vinifera roots were treated with 100 μM Cd for 0-180 min or 20-100 μM Cd for 24 h. Fluorescence confocal microscopy showed elevated hydrogen peroxide and superoxide levels in the apical root segments. Two phases (after 30 min and 24 h) of the superoxide raised levels were observed. This was accompanied by the decrease in root cell viability. Cd in concentrations between 0.005-10 mM induced significant, but different changes in membrane electrical potential (EM) of the root epidermal cells. The low concentrations of Cd (0.005-0.01 mM) caused transient EM hyperpolarization followed by depolarization, whereas by higher concentrations (0.05-5.0 mM) EM was depolarized. In any case, the depolarization or hyperpolarization were only transient up to 5 mM Cd concentration indicating that the plasma membrane function was not irreversibly destroyed. Hyperpolarization of EM induced by fusicoccin (FC) was completely suppressed only in the presence of 10 mM Cd pointing to the inhibition of H+-ATPase. The results suggest that the Cd interactions, depending on cellular development, result in activation of a complex of various mechanisms such as peroxide and hydrogen peroxide production, which in turn may be a more probable reason for the root cell responses to Cd toxicity than the transient EM changes
Optimization of selectivity by tuning column temperatures for series-coupled capillary columns in dual-oven gas chromatographic systems
A method has been developed and evaluated for optimization of the selectivity of series-coupled capillary columns in a twin-oven gas chromatographic system in the shortest possible analysis time. The temperatures of either one or both columns were varied independently (partial optimization) or simultaneously (overall optimization), in order to separate the maximum number of sample components. The method is based upon computer-aided calculation of Kováts indices of the coupled columns by means of second and third order (polynomial) functions of the temperatures of the individual columns. The applicability and limitations of the methods are discussed and illustrated with separations of a synthetic hydrocarbon mixture of 33 components
Dissimilar responses of membrane potential (EM), permeability properties and respiration to cadmium and nickel in maize root cells
The short-term treatment with Cd2+ and Ni2+ triggered transient depolarization of transplasma membrane potential (EM) in the outer cortical root cells of two maize cultivars (cv. Premia and cv. Blitz), however, both metals changed the EM in a quantitatively different way. The magnitude and duration of EM depolarization were concentration dependent and were greater in the metal susceptible cv. Blitz. The highest EM depolarization was recorded with simultaneous application of Cd2+ + Ni2+ in both maize cultivars. The EM depolarization induced by Cd2+ or Cd2+ + Ni2+ but not Ni2+ alone was accompanied with a tremendous increase of membrane conductivity, but it was not accompanied with the effect of heavy metals (HM) on respiration. Simultaneous application of fusiccocin (FC) with Cd2+ or Cd2+ + Ni2+ during the EM depolarization, inability of FC to stop the depolarization by FC-enhanced proton extrusion and rapid restoration of EM, suggested a transient inhibition of the plasma membrane H+-ATPase by these toxic metals. Our data support the opinion that differences in the effects of the studied ions were not the result of their direct action on PM, but rather of their different influence on intracellular processes within root cells
Maritime traffic externalities in the Gulf of Finland until 2030
Maritime traffic in the Gulf of Finland has grown remarkably during the 2000s. This increase has an impact on the environment and exposes it to risks. These problems should be controlled to guarantee sustainable development and the welfare of inhabitants in the area. A method for estimating the impact of ship-originated air emissions on the environment is to calculate their environmental externalities which are a part of the total marginal social costs of shipping. The internalization of externalities as a control method of transport would comply with the polluter pays principle and act as a fair traffic control method between transport modes. In this paper, we present the results of CO2, NOx, SOx and PM emissions originating from ships and their externalities in the Gulf of Finland up to 2015. The calculation algorithm developed for this study produces emission estimates per annum and converts them into externalities. We focus on passenger, tanker, general cargo, Ro-Ro, container and bulk vessel ship types representing almost 90% of the total NOx emissions of shipping in the area. Scenario modelling is a method for estimating the effects of forthcoming or planned regulations and helps with targeting emission abatement actions to maximize their profit. The results of the calculation algorithm show that externalities can be used as a consultative tool for transport-related decision-making. The costs are given at the price levels of the year 2000. The total external cost of ship-originated CO2, NOx, SOx and PM emissions in the Gulf of Finland was almost (sic)175 million in 2007. Due to increased traffic volumes, these costs will increase to nearly (sic)214 million in 2015. The majority of externalities are produced by CO2 emissions. If we deduct CO2 externalities from the results, we get total externalities of (sic)57 million in 2007. Following eight years (2015), externalities would be 28% or (sic)41 million lower. This would be as a result of regulation reducing the sulphur content of marine fuels. Regulating SOx and PM emissions will slow down the increasing trend of shipborne externalities in the Gulf of Finland; however, the externalities are still growing. In order to achieve a downward trend, the two major compounds resulting in externalities must be reduced, which requires strict actions to lower shipborne CO2 and NOx emissions
Vector coherent state representations, induced representations, and geometric quantization: II. Vector coherent state representations
It is shown here and in the preceeding paper (quant-ph/0201129) that vector
coherent state theory, the theory of induced representations, and geometric
quantization provide alternative but equivalent quantizations of an algebraic
model. The relationships are useful because some constructions are simpler and
more natural from one perspective than another. More importantly, each approach
suggests ways of generalizing its counterparts. In this paper, we focus on the
construction of quantum models for algebraic systems with intrinsic degrees of
freedom. Semi-classical partial quantizations, for which only the intrinsic
degrees of freedom are quantized, arise naturally out of this construction. The
quantization of the SU(3) and rigid rotor models are considered as examples.Comment: 31 pages, part 2 of two papers, published versio
Vector coherent state representations, induced representations, and geometric quantization: I. Scalar coherent state representations
Coherent state theory is shown to reproduce three categories of
representations of the spectrum generating algebra for an algebraic model: (i)
classical realizations which are the starting point for geometric quantization;
(ii) induced unitary representations corresponding to prequantization; and
(iii) irreducible unitary representations obtained in geometric quantization by
choice of a polarization. These representations establish an intimate relation
between coherent state theory and geometric quantization in the context of
induced representations.Comment: 29 pages, part 1 of two papers, published versio
Assessing the costs and environmental benefits of IMO regulations of ship-originated SOx and NOx emissions in the Baltic Sea
To assess the value of the environmental benefits of the Sulphur Emission regulation (SECA) that came into force in 2015, changes in depositions of SOx and NOx from ship exhaust gas emissions were modelled and monetized for the Baltic Sea region for the years 2014 and 2016. During this period, the total deposition of SOx in the study area decreased by 7.3%. The decrease in ship-originated SOx deposition from 38 kt to 3.4 kt (by over 88%) was translated into a monetary value for the ecosystem impacts of nearly 130 million USD, according to the EcoValue08 model. This is less than the modelled health benefits, but it is not insignificant. For NOx, there was no decreasing trend. The exceedance of the critical loads of SOx and NOx was also estimated. The effect of Baltic shipping on the exceedance of critical loads of acidification after SECA is very small, but Baltic shipping still has a considerable effect on the exceedance of critical loads for eutrophication
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