Shot-noise spectroscopy of energy resolved ballistic currents

We investigate the shot noise of nonequilibrium carriers injected into a ballistic conductor and interacting via long-range Coulomb forces. Coulomb interactions are shown to act as an energy analyzer of the profile of injected electrons by means of the fluctuations of the potential barrier at the emitter contact. We show that the details in the energy profile can be extracted from shot-noise measurements in the Coulomb interaction regime, but cannot be obtained from time-averaged quantities or shot-noise measurements in the absence of interactions.

Effect of long-range Coulomb interaction on shot-noise suppression in ballistic transport

We present a microscopic analysis of shot-noise suppression due to long-range Coulomb interaction in semiconductor devices under ballistic transport conditions. An ensemble Monte Carlo simulator self-consistently coupled with a Poisson solver is used for the calculations. A wide range of injection-rate densities leading to different degrees of suppression is investigated. A sharp tendency of noise suppression at increasing injection densities is found to scale with a dimensionless Debye length related to the importance of space-charge effects in the structure.

Survival of multi-drug resistant enteropathogenic Escherichia coli and Salmonella paratyphi in Vembanadu lake as a function of saltwater barrier along southwest coast of India

The objective of the study was to evaluate the survival response of multi-drug resistant enteropathogenic Escherichia coli and Salmonella paratyphi to the salinity fluctuations induced by a saltwater barrier constructed in Vembanadu lake, which separates the lake into a freshwater dominated southern and brackish water dominated northern part. Therefore, microcosms containing freshwater, brackish water and microcosms with different saline concentrations (5, 10, 15, 20, 25 ppt) inoculated with E. coli/S. paratyphi were monitored up to 34 days at 20 and 30 WC. E. coli and S. paratyphi exhibited significantly higher (p <0.05) survival at 20 WC compared to 30 WC in all microcosms. Despite fresh/brackish water, E. coli and S. paratyphi showed prolonged survival up to 34 days at both temperatures. They also demonstrated better survival potential at all tested saline concentrations except 25 ppt where a significantly higher (p<0.0001) decay was observed. Therefore, enhanced survival exhibited by the multi-drug resistant enteropathogenic E. coli and S. paratyphi over a wide range of salinity levels suggest that they are able to remain viable for a very long time at higher densities in all seasons of the year in Vembanadu lake irrespective of saline concentrations, and may pose potential public health risks during recreational activities

An ab-initio calculation of the Coulomb explosion of N_2 after heavy-ion bombardement

Self-consistent-field calculations for the total potential energy of highly ionized N_2 molecules are presented. We compare these calculations to the experimentally observed energy released in the Coulomb explosion of ionized N_2 molecules created after collision with fast heavy ions. The most important electronic states of the fragment ions are determined.

Room-temperature continuous-wave operation of GaInNAs/GaAs quantum dot laser with GaAsN barrier grown by solid source molecular beam epitaxy

We present the results of GaInNAs/GaAs quantum dot structures with GaAsN barrier layers grown by solid source molecular beam epitaxy. Extension of the emission wavelength of GaInNAs quantum dots by ~170nm was observed in samples with GaAsN barriers in place of GaAs. However, optimization of the GaAsN barrier layer thickness is necessary to avoid degradation in luminescence intensity and structural property of the GaInNAs dots. Lasers with GaInNAs quantum dots as active layer were fabricated and room-temperature continuous-wave lasing was observed for the first time. Lasing occurs via the ground state at ~1.2μm, with threshold current density of 2.1kA/cm[superscript 2] and maximum output power of 16mW. These results are significantly better than previously reported values for this quantum-dot system.

User Experience (a hidden barrier) in OER

More Open Education Resources (OER) and learning environments are being created and starting to mature and there are a number of barriers to learning and creator participation. One often overlooked barrier that has been given less attention, especially within OERs, is user experience (UX). UX is the way a person feels about using a product, system or service. We are creatures with emotional needs and, in the rush to get great content open and available sometimes the usability, the wow factor and good design principles get left by the wayside. I will demonstrate ways to think about UX for your OER and learning environments and why this is an important factor in helping engage learners with our educational materials. ‘The real payoff comes when we can make that remarkability last. When we can make people continually feel our work is worthy of discussion. When—for weeks, months, maybe even years— the people who engage with our work continue to sing its praises to everybody they meet’– (Jared Spool in Walter, A. Designing for Emotion). Walter, A. (2011) Designing for Emotion, A Book Apart. http://www.abookapart.com/products/designing-for-emotion

Coral reef : inside Australia's Great Barrier Reef.

Forma parte de un programa de lectura para la enseñanza primaria. El tamaño del libro es lo suficientemente grande como para que el profesor lo utilice para compartir la lectura del texto en clase, y pueda además desarrollar destrezas y estrategias de lectura. Se explora el mundo submarino del mayor arrecife de coral del mundo,las múltiples formas y colores de los corales, así como la variedad de animales que viven en ella, desde el animal coral o polipo hasta peces, tortugas, tiburones y animales venenosos.

Definición, hipótesis y experimentación en la Ley de Coulomb.

Fue el primero en descubrir las características de las fuerzas entre las cargas eléctricas. Su ley dice: la magnitud de cada una de las fuerzas eléctricas con que interactúan dos cargas puntuales en reposo es directamente proporcional al producto de la magnitud de ambas cargas ....

Demostración experimental de la Ley de Coulomb con el retroproyector.

Se realiza una demostración experimental de la Ley de Coulomb con el retroproyector. EI retroproyector de transparencias permite demostrar experimentalmente la Ley de Coulomb, de una manera rápida y precisa, a un conjunto numeroso de alumnos, de modo que todos ellos participen en la recogida de datos y en la interpretación de resultados. Se muestra esquemáticamente el montaje del experimento en una ilustración y se explica textualmente. La Ley de Coulomb solamente se puede aplicar a aquellas cargas cuyas dimensiones son despreciables comparadas con la distancia que las separa. En nuestros experimentos hemos comprobado que la Ley de Coulomb deja de cumplirse cuando la distancia de separación es inferior a cuatro veces el diámetro de las bolitas. Es decir, si el diámetro de éstas es de 1 cm, la distancia entre ambas bolitas debe ser mayor de 4 cm.

Comprobaci??n de la ley de Coulomb

Se presentan una serie de valores y se adjunta una gr??fica con el fin de representar la exactitud con la que se cumple la ley de Coulumb.

The mapping of the local contributions of Fermi and Coulomb correlation into intracule and extracule density distributions

The contributions of the correlated and uncorrelated components of the electron-pair density to atomic and molecular intracule I(r) and extracule E(R) densities and its Laplacian functions ∇2I(r) and ∇2E(R) are analyzed at the Hartree-Fock (HF) and configuration interaction (CI) levels of theory. The topologies of the uncorrelated components of these functions can be rationalized in terms of the corresponding one-electron densities. In contrast, by analyzing the correlated components of I(r) and E(R), namely, IC(r) and EC(R), the effect of electron Fermi and Coulomb correlation can be assessed at the HF and CI levels of theory. Moreover, the contribution of Coulomb correlation can be isolated by means of difference maps between IC(r) and EC(R) distributions calculated at the two levels of theory. As application examples, the He, Ne, and Ar atomic series, the C2-2, N2, O2+2 molecular series, and the C2H4 molecule have been investigated. For these atoms and molecules, it is found that Fermi correlation accounts for the main characteristics of IC(r) and EC(R), with Coulomb correlation increasing slightly the locality of these functions at the CI level of theory. Furthermore, IC(r), EC(R), and the associated Laplacian functions, reveal the short-ranged nature and high isotropy of Fermi and Coulomb correlation in atoms and molecules