Scaling of NonOhmic Conduction in Strongly Correlated Systems

A new scaling formalism is used to analyze nonlinear I-V data in the vicinity of metal-insulator transitions (MIT) in five manganite systems. An exponent, called the nonlinearity exponent, and an onset field for nonlinearity, both characteristic of the system under study, are obtained from the analysis. The onset field is found to have an anomalously low value corroborating the theoretically predicted electronically soft phases. The scaling functions above and below the MIT of a polycrystalline sample are found to be the same but with different exponents which are attributed to the distribution of the MIT temperatures. The applicability of the scaling in manganites underlines the universal response of the disordered systems to electric field

Nonlinear DC-response in Composites: a Percolative Study

The DC-response, namely the $I$-$V$ and $G$-$V$ charateristics, of a variety of composite materials are in general found to be nonlinear. We attempt to understand the generic nature of the response charactersistics and study the peculiarities associated with them. Our approach is based on a simple and minimal model bond percolative network. We do simulate the resistor network with appropritate linear and nonlinear bonds and obtain macroscopic nonlinear response characteristics. We discuss the associated physics. An effective medium approximation (EMA) of the corresponding resistor network is also given.Comment: Text written in RevTEX, 15 pages (20 postscript figures included), submitted to Phys. Rev. E. Some minor corrections made in the text, corrected one reference, the format changed (from 32 pages preprint to 15 pages

Optomagnetic composite medium with conducting nanoelements

A new type of metal-dielectric composites has been proposed that is characterised by a resonance-like behaviour of the effective permeability in the infrared and visible spectral ranges. This material can be referred to as optomagnetic medium. The analytical formalism developed is based on solving the scattering problem for considered inclusions with impedance boundary condition, which yields the current and charge distributions within the inclusions. The presence of the effective magnetic permeability and its resonant properties lead to novel optical effects and open new possible applications.Comment: 48 pages, 13 figures. accepted to Phys. Rev. B; to appear vol. 66, 200

Helicobacter pylori Colonization in Infants and Young Children is Not Necessarily Associated with Diarrhoea

A cohort of 151 infants and young children aged 1-23 months from a poor peri-urban community of Bangladesh was studied to determine the relationship between Helicobacter pylori colonization and morbidity due to diarrhoea. A 13C urea breath test was performed to detect the presence of H. pylori.Children were followed up at home every alternate day for 6 months and diarrhoeal morbidity datawere collected. Diarrhoeal morbidity was compared between H. pylori-positive and H. pylori-negative children. Sixty-eight (45 per cent) children were H. pylori positive and 83 (55 per cent) were H. pylori negative. During the first 1-month period following the breath test, three (4.4 per cent) H. pylori-positive and four (4.8 per cent) H. pylori-negative children had diarrhoea. Thirty-two (47 per cent) of the children in the positive group and 43 (52 per cent) in the negative group had one or more episodesof diarrhoea during the 6-month follow-up period. Median number of diarrhoeal episodes was 1.0(range 1.0-4.0) in the H. pylori-positive children and 2.0 (range 1.0-5.0) in the H. pylori-negativechildren (p = 0.19). No significant difference was observed in the cumulative days with diarrhoea.The results of this study suggest that H. pylori colonization is not associated with diarrhoealmorbidity in infants and young childre

Quantum Size Effect transition in percolating nanocomposite films

We report on unique electronic properties in Fe-SiO2 nanocomposite thin films in the vicinity of the percolation threshold. The electronic transport is dominated by quantum corrections to the metallic conduction of the Infinite Cluster (IC). At low temperature, mesoscopic effects revealed on the conductivity, Hall effect experiments and low frequency electrical noise (random telegraph noise and 1/f noise) strongly support the existence of a temperature-induced Quantum Size Effect (QSE) transition in the metallic conduction path. Below a critical temperature related to the geometrical constriction sizes of the IC, the electronic conductivity is mainly governed by active tunnel conductance across barriers in the metallic network. The high 1/f noise level and the random telegraph noise are consistently explained by random potential modulation of the barriers transmittance due to local Coulomb charges. Our results provide evidence that a lowering of the temperature is somehow equivalent to a decrease of the metal fraction in the vicinity of the percolation limit.Comment: 21 pages, 8 figure

Variation in gas and volatile compound emissions from human urine as it ages, measured by an electronic nose

The medical profession is becoming ever more interested in the use of gas-phase biomarkers for disease identification and monitoring. This is due in part to its rapid analysis time and low test cost, which makes it attractive for many different clinical arenas. One technology that is showing promise for analyzing these gas-phase biomarkers is the electronic nose-an instrument designed to replicate the biological olfactory system. Of the possible biological media available to "sniff", urine is becoming ever more important as it is easy to collect and to store for batch testing. However, this raises the question of sample storage shelf-life, even at -80 °C. Here we investigated the effect of storage time (years) on stability and reproducibility of total gas/vapour emissions from urine samples. Urine samples from 87 patients with Type 2 Diabetes Mellitus were collected over a four-year period and stored at -80 °C. These samples were then analyzed using FAIMS (field-asymmetric ion mobility spectrometry-a type of electronic nose). It was discovered that gas emissions (concentration and diversity) reduced over time. However, there was less variation in the initial nine months of storage with greater uniformity and stability of concentrations together with tighter clustering of the total number of chemicals released. This suggests that nine months could be considered a general guide to a sample shelf-life

An Interdisciplinary Perspective on Education Service Systems

Part 3: Finance and Service ScienceInternational audienceThe increased complexity in education systems has given rise to a number of intersecting trends and calling for a discipline to integrate across academic silos. As the concept of service innovation advances more rapidly into education services; industry, government, and academy are awakened to the concept of embedding services innovation. This theoretical paper offers an integrated framework for education systems (IFES) covering two intersecting dimensions where service innovation and service science can take place. As an effort to contribute in the area of service innovation and service sciences, an interdisciplinary approach is applied, interconnecting an array of competences across the different stakeholders. It is hypothesized that to increase productivity in education industries, interconnecting knowledge and resources from diverse areas and across different stakeholders through the co-lineation of four dimensions: (1) information, communications and technology; (2) skills and tools; (3) people and attitudes; (4) systems, processes and management; are essential to creating service innovation. This paper contributes a perspective of interconnectivity balanced with harmony that are crucial for effective productivity and service innovation by adopting a service science approach