Selective Behaviour of Honeybees in Acquiring European Propolis Plant Precursors

Honey bees harvest resins from various plant species and use them in the hive as propolis. While there have been a number of studies concerning the chemical composition of this antimicrobial product, little is known about selective behavior and bee preference when different potential plant sources of resin are available. The main objective of this paper was to investigate some aspects of behavioral patterns of honeybees in the context of resin acquisition. Samples of propolis originating from temperate zones of Europe and the supposed botanical precursors of the product were analyzed. Taxonomical markers of bud resins of two white birch species, aspen, black poplar, horse-chestnut, black alder, and Scots pine were determined through GC-MS analysis. All these trees have been reported as sources of propolis, but comparisons of the chemical composition of their bud resins with the compositions of propolis samples from seven European countries have demonstrated the presence of taxonomical markers only from black poplar, aspen, and one species of birch. This suggests selective behavior during the collection of bud resins by honeybees. To examine the causes of such selectivity, the antimicrobial properties of bud resins were determined. Horse-chestnut resins had lower antimicrobial activity than the other resins which did not differ significantly.     

Coexistence of Superconductivity and Antiferromagnetism in Heavy-Fermion Intermetallic Compound CeRhIn5

An interference of heavy-fermion superconductivity (SC) and antiferromagnetism (AFM) has been studied in the framework of the periodic Anderson model with the superexchange interaction between localized electrons. It has been shown that pressure-induced energy change of the localized states leads to modifying antiferromagnetic and superconducting order parameters. Conditions have been found for the coexistence of SC and AFM in the model. Theoretical results of the pressure effects on the ground state character of the heavy-fermion systems are in good agreement with experimental data for a rare-earth intermetallic compound CeRhIn₅. The divergence of the effective electron mass produced by suppressing the long-range antiferromagnetic order has also been analyzed in the same framework.     

Ergodynamics and macroergonomics in analysis of decision‐making efficiency and complexity

The principles of macroergonomics and the laws of ergodynamics are reviewed. The theories of mutual adaptation and transformation dynamics are presented as a complex basis of the ergodynamics, and they are offered as paradigms for macroergonomic evaluation and design of sociotechnical or human‐machine‐environment decision‐making systems (HMES). Criteria and factors of decision‐making efficiency are studied for different cognitive strategies and their transformations in the course of long‐term training and short‐term decision making in emergencies. Sample system criteria and design guidelines, based on the results of both laboratory studies and actual research and design applications, are provided. A combination of macroergonomics and ergodynamics helps ergonomists to meet rapidly growing requirements of practice and overcome a narrow approach to the workstations analysis when a broader view of complex multilevel system leads to success and instead of traditional static approach the analysis of transformations in technologies, management structures, and work skills is needed.     

A modified tank in series model for cogeneration of hydroxylamine and electricity in the nitric oxide/hydrogen fuel cell

This work presents a modified TSR model of the nitric oxide/hydrogen fuel cell operating in potentiostatic mode with the co-current flow direction. The developed model accounts for the component and the energy balances in gas channels, liquid catholyte and catalyst layers together with charge balances at electrode/electrolyte interfaces. The simulation results indicate the influence of catalyst selectivity and mass transfer on the distribution of concentration, temperature and current density.     

Modification of Marx generator with a doubling of output voltage

A multistage generator of high‐voltage pulses with a doubling of output voltage built according to the Marx scheme is presented. A specific feature of the generator circuit design is the substitution of charging diodes for charging resistors and connection of the supplying voltage through an inductor. Such a design makes it possible to double the amplitude of pulses across a load, which is proportional to the number of connected stages, and to minimize the power loss during the charging of storage capacitors. Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of channel cracks on fiber fracture in one-component material with unidirectional fibrous structure

One-component materials with unidirectional fibrous structure are a new class of structural materials that are mechanically similar to biological ones. These contain channel cracks (CC) and weak interfaces in the structure, which are the result of production technologies. Effect of the CC size and the shear strength of contacts between fibers were investigated in the three-dimensional analysis of the elastic and inelastic shear extensions at the interface of the cracked fiber in the bundle of undamaged fibers under tension. The fiber stacking in the bundle is hexagonal. The fiber cross-sections are regular hexagons. It is found that the energy dissipation at the interface of the cracked fiber, the stress intensity factor and the crack opening displacement for the crack in the fiber and the length of the interface with the non-zero shear stresses are determined by the product of the contact cohesive shear strength and the contact width. At the optimal cohesive shear strength of the interfaces, the channel cracks shall not prejudice to the basic strength characteristics of the material.     

A Mathematical Approach in the Design of Arterial Bypass Using Unsteady Stokes Equations

In this paper we present an approach for the study of Aorto-Coronaric bypass anastomoses configurations using unsteady Stokes equations. The theory of optimal control based on adjoint formulation is applied in order to optimize the shape of the zone of the incoming branch of the bypass (the toe) into the coronary according to several optimality criteria.Dedicated to David Gottlieb on the occasion of his 60th birthdayValery Agoshkov: This work has been prepared when the first author was a visiting professor at Institut d’Analyse et Calcul Scientifique of the école Polytechnique Fédérale de Lausanne     

Matrix formulation of fuzzy rule-based systems

In this paper, a matrix formulation of fuzzy rule based systems is introduced. A gradient descent training algorithm for the determination of the unknown parameters can also be expressed in a matrix form for various adaptive fuzzy networks. When converting a rule-based system to the proposed matrix formulation, only three sets of linear/nonlinear equations are required instead of set of rules and an inference mechanism. There are a number of advantages which the matrix formulation has compared with the linguistic approach. Firstly, it obviates the differences among the various architectures; and secondly, it is much easier to organize data in the implementation or simulation of the fuzzy system. The formulation will be illustrated by a number of examples.     

The solution of problems dealing with convective heat transfer in tubes by the bubnov-galerkin method

An analytical method is developed for the solution of internal problems of nonsteady heat transfer for the laminar flow of a fluid through tubes exhibiting various perpendicular cross sections. The method is based on the combined application of integral transformations and variational calculus. Transient processes are studied for the nonsteady heat transfer in circular tubes and in plane-parallel channels, when the temperature at the inlet varies according to a specified law.     

MALDI matrices for biomolecular analysis based on functionalized carbon nanomaterials

When used in small molar ratios of matrix to analyte, derivatized fullerenes and single wall nanotubes are shown to be efficient matrices for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The mixing of an acidic functionalized fullerene with a solution of bioanalyte, depositing a dried droplet, and irradiating with a pulsed nitrogen laser yields protonated or cationized molecular ions. Derivatized fullerenes could offer several advantages over conventional MALDI matrices: a high analyte ionization efficiency, a small molar ratios (less than 1) of matrix/analyte, and a broader optical absorption spectrum, which should obviate specific wavelength lasers for MALDI acquisitions. The major disadvantage to the use of fullerenes is the isobaric interference between matrix and analyte ions; however, it is overcome by using MALDI-ion mobility time-of-flight (IM-oTOF) mass spectrometry to preseparate carbon cluster ions from bioanalyte ions prior to TOF mass analysis. However, an alternative to the dried droplet preparation of fullerene MALDI samples is the aerosolization of matrix-analyte solutions (or slurries) followed by impacting the aerosol onto a stainless surface. We also demonstrate that the fullerene matrices can be used to acquire spectra from rat brain tissue.