Focus on advances in electrical impedance tomography

Editoria

The Effects of Gamma-irradiation on Seed Germination and Plant Stem Growth in Four Species of Plants

Today we are in the modern nuclear age of which several nations of the world have role. The United States is a forerunner in the world attempt to conquer the atom and its energy. The American concern in this field is primarily in three areas: (1) the harnessing of the nuclear energy for economic reasons, and (2) the magnitude of nuclear energy as a destructive threat, and (3) the resultant effects of ionizing radiation on biological organism. This study was pertinent to the third area listed above. It was concerned with the effect of gamma-irradiation on seed germination and its resultant effect on plant growth

A simple computer program for calculating stress and strain rate in 2D viscous inclusion-matrix systems

Computer-based numerical solutions of geomechanical problems are important to understand the processes forming rock structures as well as to quantify the associated pressure, stresses and strain rates. However, the development of such computer programs and the underlying mathematical methods are commonly not taught in a standard structural geology curriculum. Here, we present a simple computer program to calculate the stress, pressure, velocity and strain rate fields for two-dimensional (2D) viscous inclusion-matrix systems under pure shear and simple shear. The main aim of our contribution is to explain this computer program in a simple and transparent way, so that it can be used for introductory courses on geomechanical numerical modelling in structural geology. We present the governing equations of 2D viscous deformation and program the equations in the same order and style, so that the equations are still recognizable in the computer program. The computer program can treat stiff and weak inclusions of any shape and considers both linear and power-law viscous flow laws. We present numerical calculations for various inclusion-matrix scenarios. The program is written with the software MATLAB, is provided as supplementary material, and can also be run with the freely available software GNU Octave

Retaining nurses in metropolitan areas: insights from senior nurse and human resource managers.

AIM: To investigate the views of senior nurse and human resource managers of strategies to retain hospital nurses in a metropolitan area. BACKGROUND: Against a global shortage, retaining nurses is a management imperative for the quality of hospital services. METHOD: Semi-structured interviews, thematically analysed. RESULTS: Metropolitan areas have many health organisations in geographical proximity, offering nurses choices in employer and employment. Senior nurse and human resource managers recognised the complexity of factors influencing nurse turnover, including those that 'pulled' nurses out of their jobs to other posts and factors that 'pushed' nurses to leave. Four themes emerged in retaining nurses: strategy and leadership, including analysis of workforce and leavers' data, remuneration, the type of nursing work and career development and the immediate work environment. CONCLUSIONS: In contexts where multiple organisations compete for nurses, addressing retention through strategic leadership is likely to be important in paying due attention and apportioning resources to effective strategies. IMPLICATIONS FOR NURSING MANAGEMENT: Aside from good human resource management practices for all, strategies tailored to different segments of the nursing workforce are likely to be important. This metropolitan study suggests attention should be paid to strategies that address remuneration, progressing nursing careers and the immediate work environment

Design and implementation of an electro-optical backplane with pluggable in-plane connectors

The design, implementation and characterisation of an electro-optical backplane and an active pluggable in-plane optical connector technology is presented. The connection architecture adopted allows line cards to be mated to and unmated from a passive electro-optical backplane with embedded polymeric waveguides. The active connectors incorporate a photonics interface operating at 850 nm and a mechanism to passively align the interface to the optical waveguides embedded in the backplane. A demonstration platform has been constructed to assess the viability of embedded electro-optical backplane technology in dense data storage systems. The demonstration platform includes four switch cards, which connect both optically and electronically to the electro-optical backplane in a chassis. These switch cards are controlled by a single board computer across a Compact PCI bus on the backplane. The electrooptical backplane is comprised of copper layers for power and low speed bus communication and one polymeric optical layer, wherein waveguides have been patterned by a direct laser writing scheme. The optical waveguide design includes densely arrayed multimode waveguides with a centre to centre pitch of 250μm between adjacent channels, multiple cascaded waveguide bends, non-orthogonal crossovers and in-plane connector interfaces. In addition, a novel passive alignment method has been employed to simplify high precision assembly of the optical receptacles on the backplane. The in-plane connector interface is based on a two lens free space coupling solution, which reduces susceptibility to contamination. Successful transfer of 10.3 Gb/s data along multiple waveguides in the electro-optical backplane has been demonstrated and characterised

A simple method for the determination of refractive indices of (rough) transparent solids

Simple methods for the determination of refractive indices of transparent polymers and inorganic and organic solids of irregular geometry or with scratched or corrugated surfaces are rare. A classical procedure is based on the invisibility of a body immersed in a liquid with the same refractive index as that of the body. In order to avoid the laborious procedure connected with the search for a liquid with matching refractive index and to find an approach which is independent of the observation by eye, we describe here a modified immersion method which allows the ready determination of the refractive index of solids. The present method is based on the interpolation of the maximum transmission (nTmax) of a solid immersed in liquids with different, typically non-matching, refractive indices. Illustrations with quartz glass, crown glass and poly(vinylidene fluoride) (PVDF) films showed that nTmax can be determined with a reproducibility of ± 0.003. By comparison with refractive indices determined by ellipsometry, it was concluded that the refractive index of a solid can be determined with the modified immersion method within an accuracy better than ± 0.01 when systematic errors resulting from the fit method are also taken into consideratio