AlAs and InAs mode LO phonon emission assisted tunneling in (InGa)As/(AlIn)As double barrier structures

WE present a magnetospectral analysis of the different scattering processes involved in the tunneling current of an MBE grown (InGa)As/(AlIn)As double barrier diode. At zero magnetic field, the I(V) characteristics of the sample show a replica peak. We demonstrate that this peak is associated to the tunneling of electrons from the emitter to the quantum well, assisted by the emission of an AlAs mode LO phonon. The presence of InAs mode LO phonon emission processes is also revealed at high magnetic fields. At a field B where the crossing between InAs and AlAs mode phonon emission processes occurs, a change in the B-dependent behavior of the peak voltage positions is observed, that we attribute to a change in the dominant process. The higher probability for InAs mode LO phonon emission processes is explained by the stronger coupling of electrons to this mode in this system, in agreement with previous results on (InGa)As/(AlIn)As single heterojunctions.     

An analysis of IT/IS outsourcing provider selection for small- and medium-sized enterprises in Taiwan

Outsourcing is important in highly diversified business environments, but while there have been many studies on outsourcing, none have explicitly tackled the problem of how SMEs should assess and select their outsourcer. Numerous benefits might be gained if SMEs could utilize evaluation models to help select their IT/IS outsourcer effectively. Prejudices arising from selection through impartial analysis could be avoided and a more accurate and an objective decision could be made. We investigated the selection process of an enterprise needing an IT/IS outsourcing provider in Taiwan. Our recommended process quantitatively sorts the criteria using the AHP. An evaluation model was developed based on the needs of the SME who should use it to obtain a better outsourcing provider resulting from improved information vital to maintain outsourcing efficiency. Use of our model should reduce costs and potential risks in adopting new IT/IS applications and promote an objective standard with which to evaluate IT/IS outsourcing providers.     

Effects of age and body mass index on breast characteristics: a cluster analysis

Limited research has quantified variation in the characteristics of the breasts among women and determined how these breast characteristics are influenced by age and body mass. The aim of this study was to classify the breasts of women in the community into different categories based on comprehensive and objective measurements of the characteristics of their breasts and torsos, and to determine the effect of age and body mass index on the prevalence of these breast categories. Four breast characteristic clusters were identified (X-Large, Very-ptotic & Splayed; Large, Ptotic & Splayed; Medium & Mildly-ptotic; and Small & Non-ptotic), with age and BMI shown to significantly affect the breast characteristic clusters. These results highlight the difference in breast characteristics exhibited among women and how these clusters are affected by age and BMI. The breast characteristic clusters identified in this study could be used as a basis for future bra designs and sizing systems in order to improve bra fit for women.

Practitioner summary: This original research provides evidence for bra designers and manufacturers on the diverse breast characteristics exhibited by women within the population and the significant effect that both body mass index and age have on the breast characteristic clusters. Future bra designs should consider the variation in breast characteristics among women.

Abbreviations: BMI: Body Mass Index; UBCC: Under-bust chest circumference     

Output mini-max control for polynomial systems: analysis and applications

This paper presents a solution to a robust optimal regulation problem for a nonlinear polynomial system affected by parametric and matched uncertainties, which is based only on partial state information. The parameters describing the dynamics of the nonlinear polynomial plant depend on a vector of unknown parameters, which belongs to a finite parametric set, and the application of a certain control input is associated with the worst or least favourable value of the unknown parameter. A high-order sliding mode state reconstructor is designed for the nonlinear plant in such a way that the previously designed control can be applied for a system with incomplete information. Additionally, the matched uncertainty is also compensated by means of the same output-based regulator. The obtained algorithm is applied to control an uncertain nonlinear inductor circuit of the third order and a mechanical pendulum of the third order, successfully verifying the effectiveness of the developed approach.     

Reservoir Operation by a New Evolutionary Algorithm: Kidney Algorithm

This article shows an application of a new algorithm, called kidney algorithm, for reservoir operation which employs three different operators, namely filtration, secretion, and excretion that lead to faster convergence and more accurate solutions. The kidney algorithm (KA) was used for generating the optimal operation of a reservoir namely; Aydoghmoush dam in eastern Azerbaijan province in Iran whose purpose was to decrease irrigation deficit downstream of the dam. Results from the algorithm were compared with those by other evolutionary algorithms, including bat (BA), genetic (GA), particle swarm (PSO), shark (SA), and weed algorithms (WA). The results showed that the kidney algorithm provided the best performance against the other evolutionary algorithms. For example, the computational time for the KA was 3 s, 2 s, 4 s, 6 s and 3 s less than BA, SA, GA PSA and WA, respectively. Also, the objective function for the optimization problem was the minimization of the irrigation deficits and its value for the KA was 55%, 28%, 52%, 44 and 54% less than GA, SA, WA, BA and PSA, respectively. Also, the different performance indexes showed the superiority of the KA compared to the other algorithms. For example, the root mean square error for the KA was 74%, 61%, 68%, 33 and 54% less than GA, SA, WA, BA and PSA, respectively. Different multi criteria decision models were used to select the best models. The results showed that the KA achieved the first rank for the optimization problem and thus, it shows a high potential to be applied for different problems in the field of water resources management.     

The Role of Spill and Evaporation in Reservoir Optimization Models

This technical note is divided into two parts. The first one investigates the necessity to explicitly incorporate spills into reservoir optimization models based on linear or nonlinear programming and presents a scheme to accomplish this task. The second part shows how reservoir optimization models may apply hedging strategies during droughts even for systems located in semiarid conditions where high evaporation rates could threat the retention of water in storage.     

Factors affecting the adoption of green supply chain management practices in Brazil: empirical evidence

The aim of this study is to identify and analyse the factors that affect the adoption of Green Supply Chain Management practices based on empirical evidence from the Brazilian electronics sector. Data are collected in a survey of 100 electronics companies and analysed using statistical analysis of variance and regression methods. The study finds that the size of the company, previous experience with Environmental Management Systems, and the use of hazardous inputs are positively correlated with GSCM practices adoption. Surprisingly, formal pressure from the stronger tier/player in the supply chain is not correlated with the adoption of GSCM practices. Finally, we present some explanations for these findings and suggestions for future research.     

Combined blockade of serotonergic and muscarinic transmission disrupts the anterior thalamic head direction signal.

Head direction (HD) cells have been speculated to be part of a network mediating navigational behavior. Previous work has shown that combined administration of serotonergic and muscarinic antagonists eliminates hippocampal theta activity and produces navigational deficits more severe than blockade of either neurotransmitter system alone. The authors sought to assess this effect on the directional characteristics of HD cells. HD cells were recorded from the anterior dorsal thalamus of Long-Evans rats before and after administration of the serotonergic antagonist methiothepin, the muscarinic antagonist scopolamine, both drugs, or saline. Combined drug administration produced HD cells with preferred directions that drifted within recording sessions. In addition, cells showed shifts in the preferred directions at the start of a session relative to the position of the major landmarks, suggesting that combined drug administration led to deficits in landmark control of the HD system. Single drug exposures to methiothepin or scopolamine did not noticeably affect the directional characteristics of HD cells. This finding that navigation-impairing drugs can disrupt the HD signal provides further evidence that this network plays an important role in navigational behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Women and Subsistence Food Technology: The Arctic Seal Poke Storage System

This study focuses on the pan-arctic seal poke storage system—an innovative and effective food storage and preservation system that was likely used for thousands of years but today is rarely seen. Women expertly processed the skin of a whole seal into a leak proof pliable container. The result was a technology that provided the safe storage and transport of rendered seal oil—a highly prized food and fuel source—and the preservation and taste and texture enhancement of other foods submerged in the oil. Sea mammal oil was (and remains largely so) unequivocally one of the most critical subsistence resources in the arctic. Here we draw from the ethnographic record and our own field observations in Alaska to discuss the seal poke storage system and implications of women's fundamental role in complex food storage technologies.     

Radiation hardening of gated x-ray imagers for the National Ignition Facility (invited)

The National Ignition Facility will soon be producing x-ray flux and neutron yields higher than any produced in laser driven implosion experiments in the past. Even a non-igniting capsule will require x-ray imaging of near burning plasmas at 10(17) neutrons, requiring x-ray recording systems to work in more hostile conditions than we have encountered in past laser facilities. We will present modeling, experimental data and design concepts for x-ray imaging with electronic recording systems for this environment (ARIANE). A novel instrument, active readout in a nuclear environment, is described which uses the time-of-flight difference between the gated x-ray signal and the neutron which induces a background signal to increase the yield at which gated cameras can be used.