Scaling laws for the decay of multiqubit entanglement

We investigate the decay of entanglement of generalized N-particle Greenberger-Horne-Zeilinger (GHZ) states interacting with independent reservoirs. Scaling laws for the decay of entanglement and for its finite-time extinction (sudden death) are derived for different types of reservoirs. The latter is found to increase with N. However, entanglement becomes arbitrarily small, and therefore useless as a resource, much before it completely disappears, around a time which is inversely proportional to the number of particles. We also show that the decay of multiparticle GHZ states can generate bound entangled states.     

Dynamic analysis: a new point of view

In this article, an alternative to the classical dynamic equation formulation is presented. To achieve this goal, we need to derive the reciprocal theorem in rates and the principle of virtual work in rates, in a small deformation regime, with which we will be able to obtain an expression for damping force. In this new formulation, some terms that are not commonly considered in the classical formulation appear, e.g., the term that is function of jerk (the rate of change of acceleration). Moreover, in this formulation the term that characterizes material nonlinearity, in dynamic analysis, appears naturally.     

Capillary gas chromatography of amino acids as their tert-butyldimethylsilyl derivatives in the analysis of serum amino acids in metabolic diseases

Reaction of amino acids with N-methyl-N-(tert-butyldimethylsilyl)trifluoroaceamide (MTbSTFA) in acetonitrile affords good yields of amino acid derivatives with excellent gas chromatographic and mass spectrometric properties. The single-step derivatization procedure is highly reproducible. The TBDMS amino acids are stable at room temperature for at least three days. Only a single peak is observed for each amino acid. The procedure allows simultaneous analysis of asparagine and glutamine together with other serum amino acids. Separation is achieved on a borosilicate glass capillary coated with OV-1. The mass spectra of the TBDMS amino acids possess characteristic diagnostic ions. These properties were used in the sensitive detection by GC-MS and SIM-GC-MS of GABA and pipecolic acid in the serum of a newborn suspected of a Zellweger-type syndrome, which could not be detected by other methods.     

Use of computerized pattern recognition of triglyceride profiles in monitoring SCF-CO2 extraction of fatty oils

High pressure extraction of vegetable fatty oils by supercritical fluid carbon dioxide was investigated. Pressures from 9 to 20 MPa at 40°C were used. The extracts were monitored by high temperature capillary gas chromatography for sterol and tri-glyceride composition. The quality of the extracted oils was evaluated by numerical taxonomy methods. The extraction products compared well with the characteristics of commercial fatty oils of the same vegetable origin. No significant qualitative variation was detected in the pressure range studied.     

EPR study of the T2+ center in the paraelectric and antiferroelectric phases of NH4H2PO4

The EPR T

²⁺ center in NH₄H₂PO₄ was studied in the range of temperature 85K – 175K which includes the antiferroelectric transition. The center has the symmetry of NH⁺₄ site, where it goes substitutionally, in both the paraelectric and antiferroelectric phases. In the antiferr$\text{o}$electric phase there is a charge compensations mechanism involving the repulsion of one of the neighbor protons in the hydrogen bond. A measurement of the splitting of the resonance lines for the field along the cristallographic direction $\text{a}$ is presented as a function of temperature. This splitting is proportional to the order parameter.     

The stability of the metal complexes of cyclic tetra-aza tetra-acetic acids

The stability constants of the complexes formed by three tetra-aza macrocyclic complexones (DOTA, TRITA and TETA) with Mn(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+) and Pb(2+) were determined with an automated titration instrument with data acquisition and the calculations were performed with the Superquad program, confirming and extending the range of values previously available. Both 1:1 and 2:1 metal-to-ligand complexes were now considered including their protonated species. The results show that DOTA is a powerful but unselective ligand whereas TETA, although not so powerful as DOTA, is an interesting selective ligand for pairs of metal ions, e.g., Cd(2+) and Pb(2+).     

Studies of some duality properties in the Li and Reeves model

In 1999, Li and Reeves presented the so-called MCDEA (Multiple Criteria Data Envelopment Analysis) model. This model is in fact a three objective linear model. It may be used to improve the discriminatory power of the DEA models, as well as generate a more reasonable distribution of the inputs and outputs weights. Besides the classical optimization of the efficiency index, Li and Reeves introduced two other objective functions, called minisum and minimax. Despite of being an important approach, it does not provide benchmarks or targets for inefficient DMUs. Benchmarks and targets are one of the most important DEA features and in standard DEA are determined using the dual (envelope) model. In this paper, we introduce an approach of the MCDEA dual formulation taking into account only two objective functions at each time. Combining both partial models we suggest benchmarks for each inefficient DMU.     

Rigidity theorems for complete spacelike hypersurfaces with constant scalar curvature in De Sitter space

In this paper we give a partially affirmative answer to the following question posed by Haizhong Li: is a complete spacelike hypersurface in De Sitter space , n?3, with constant normalized scalar curvature R satisfying totally umbilical?