A quantitative evaluation of the reliability of calculated decay properties of nuclei in the mass region A=24−28

Electromagnetic transition rates and logft values were calculated for transitions between positive-parity states in theA=24?28 mass region. The wave functions used were taken from a previous paper. In general we found satisfactory agreement with experiment. In order to have a measure of the stability of the results against changes in the Hamiltonian a method was developed for assigning errors to calculated transition properties. The renormalized single-particle matrix elements of theE2 andM 1 transition operators were determined in a phenomenological way. To this end use was made of the errors just mentioned. It was found that good agreement was obtained with bare-nucleonM 1 singleparticle matrix elements and a state independent effective isoscalar charge for theE 2 operator. Predictions for static moments are given.     

Jahn-Teller distortion,ferromagnetic coupling,and electron delocalization in a high-spin Fe–Fe bonded dimer

Fe₂(N,N’-diphenylformamidinate)₄, 1, first synthesized in 1994, is one of very few non-organometallic compounds with Fe–Fe distances, (2.46 Å) suggestive of an Fe–Fe bond. The electronic structure of 1 has been unclear because of its distorted D₂ geometry, as well as its reported S = 4 ground state. Computational investigations using DFT methods have shown that the D₂ geometry is the result of a Jahn-Teller distortion away from D₄ symmetry, in which the ground state would be orbitally degenerate. Broken symmetry methods have shown that ferromagnetic coupling between the two high-spin Fe(II) ions in 1 is a consequence of spin delocalization caused by a three-electron σ bond and a weaker three-electron δ bond between the Fe atoms. The relationship between ferromagnetic coupling and an Fe–Fe bond is established from results using hybrid functionals having variable amounts of Hartree-Fock exchange, which is found, surprisingly, to mitigate Fe–Fe bonding.     

Coordination mechanisms for inventory control in three-echelon serial and distribution systems

This paper is concerned with the coordination of inventory control in three-echelon serial and distribution systems under decentralized control. All installations in these supply chains track echelon inventories. Under decentralized control the installations will decide upon base stock levels that minimize their own inventory costs. In general these levels do not coincide with the optimal base stock levels in the global optimum of the chain under centralized control. Hence, the total cost under decentralized control is larger than under centralized control. To remove this cost inefficiency, two simple coordination mechanisms are presented: one for serial systems and one for distribution systems. Both mechanisms are initiated by the most downstream installation(s). The upstream installation increases its base stock level while the downstream installation compensates the upstream one for the increase of costs and provides it with a part of its gain from coordination. It is shown that both coordination mechanisms result in the global optimum of the chain being the unique Nash equilibrium of the corresponding strategic game. Furthermore, all installations agree upon the use of these mechanisms because they result in lower costs per installation. The practical implementation of these mechanisms is discussed.     

Stereoselective total synthesis of aminoiminohexitols via carbamate annulation

New methodology for the preparation of a variety of aminoiminohextitols is described. Key in the synthesis is the application of a diastereoselective Strecker reaction and the extension of our carbamate annulation methodology to protected and functionalized alkenylamines. Insight into the effects that the substitution patterns of the alkenylamines have on the diastereoselectivity of the iodocyclization and carbamate annulation is discussed. An evaluation of the glycosidase inhibitory activity of the aminoiminohexitols and derivatives is also presented, with the previously undisclosed D-talo isomer showing good selective inhibition of β-D-glucosidase.     

Die PrÄmienanpassungsautomatik in der Krankenversicherung

Blätter der DGVFM - Die PrÄmienanpassungsautomatik in der deutschen privaten Krankenversicherung wurde aus einer Notlage heraus entwickelt. Diese Notlage war durch den immensen Anstieg...     

Identifiability and observability analysis for experimental design in nonlinear dynamical models

Dynamical models of cellular processes promise to yield new insights into the underlying systems and their biological interpretation. The processes are usually nonlinear, high dimensional, and time-resolved experimental data of the processes are sparse. Therefore, parameter estimation faces the challenges of structural and practical nonidentifiability. Nonidentifiability of parameters induces nonobservability of trajectories, reducing the predictive power of the model. We will discuss a generic approach for nonlinear models that allows for identifiability and observability analysis by means of a realistic example from systems biology. The results will be utilized to design new experiments that enhance model predictiveness, illustrating the iterative cycle between modeling and experimentation in systems biology.     

De novo synthesis of aceric acid and an aceric acid building block

The de novo synthesis of an aceric acid thioglycoside building block and the total synthesis of the plant carbohydrate aceric acid are described via a highly convergent strategy. Aldol reaction of acetaldehyde and a protected tartaric acid derivative provided the open chain carbohydrate. Subsequent acid treatment yielded the aceric acid thioglycoside in 35% total yield over five steps. Oxidative cleavage of the thioketal in the open chain carbohydrate and basic hydrolysis of the methyl ester furnished fully deprotected aceric acid in 31% yield over six steps.     

An Electron‐Rich Cyclic (Alkyl)(Amino)Carbene on Au(111), Ag(111), and Cu(111) Surfaces

The structural properties and binding motif of a strongly σ‐electron‐donating N‐heterocyclic carbene have been investigated on different transition‐metal surfaces. The examined cyclic (alkyl)(amino)carbene (CAAC) was found to be mobile on surfaces, and molecular islands with short‐range order could be found at high coverage. A combination of scanning tunneling microscopy (STM), X‐ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations highlights how CAACs bind to the surface, which is of tremendous importance to gain an understanding of heterogeneous catalysts bearing CAACs as ligands.