A self‐scalable load injection service

Load testing of applications is an important and costly activity for software provider companies. Classical solutions are very difficult to set up statically, and their cost is prohibitive in terms of both human and hardware resources. Virtualized cloud computing platforms provide new opportunities for stressing an application's scalability, by providing a large range of flexible and less expensive (pay‐per‐use model) computation units. On the basis of these advantages, load testing solutions could be provided on demand in the cloud. This paper describes a Benchmark‐as‐a‐Service solution that automatically scales the load injection platform and facilitates its setup according to load profiles. Our approach is based on: (i) virtualization of the benchmarking platform to create self‐scaling injectors; (ii) online calibration to characterize the injector's capacity and impact on the benched application; and (iii) a provisioning solution to appropriately scale the load injection platform ahead of time. We also report experiments on a benchmark illustrating the benefits of this system in terms of cost and resource reductions. Copyright © 2013 John Wiley & Sons, Ltd.     

Probabilistic Weibull behavior and mechanical properties of MEMS brittle materials

The objective of this work is to present a brief overview of a probabilistic design methodology for brittle structures, review the literature for evidence of probabilistic behavior in the mechanical properties of MEMS (especially strength), and to investigate whether evidence exists that a probabilistic Weibull effect exists at the structural microscale. Since many MEMS devices are fabricated from brittle materials, that raises the question whether these miniature structures behave similar to bulk ceramics. For bulk ceramics, the term Weibull effect is used to indicate that significant scatter in fracture strength exists, hence requiring probabilistic rather than deterministic treatment. In addition, the material's strength behavior can be described in terms of the Weakest Link Theory (WLT) leading to strength dependence on the component's size (average strength decreases as size increases), and geometry/loading configuration (stress distribution). Test methods used to assess the mechanical properties of MEMS, especially strength, are reviewed. Four materials commonly used to fabricate MEMS devices are reviewed in this report. These materials are polysilicon, single crystal silicon (SCS), silicon nitride, and silicon carbide.     

Drift hole mobility in strained and unstrained doped Si1-xGex alloys

Results of the drift hole mobility in strained and unstrained SiGe alloys are reported for Ge fractions varying from 0 to 30% and doping levels of 10¹⁵-10¹⁹ cm^-3. The mobilities are calculated taking into account acoustic, optical, alloy, and ionized-impurity scattering. The mobilities are then compared with experimental results for a boron doping concentration of 2×10¹⁹ cm^-3. Good agreement between experimental and theoretical values is obtained. The results show an increase in the mobility relative to that of silicon     

Artificial neural networks for coordination and control: The portability of experiential representations

It is time to locate connectionist representation theory in the new wave of robotics research. The utility of representations developed in artificial neural networks (ANNs) during learning has been demonstrated in cognitive science research since the 1980s. The research reported here puts learned representations to work in a decentered control task, the disembodied arm problem, in which a mobile robot operates an arm fixed to a table to pick up objects. There is no physical linkage between the arm and the robot and so the robot's point of view must be decentered. This is done by developing a modular Artificial Neural Net system in three stages: (i) a classifier net is trained with laser scan data to output transformationally invariant position classes; (ii) an arm net is trained for picking up objects; (iii) an inter net is trained to communicate and coordinate the sensing and acting. The completed system is shown to create new nonsymbolic transformationally invariant representations in order to perform the effective generalization of decentered viewpoints.     

Effect of thermal treatment on ZnO substrate for epitaxial growth

ZnO is a highly efficient photon emitter, and has optical and piezoelectric properties that are attractive for a variety of applications in sensors and potentially optoelectronic devices such as emitters. Due to its identical stacking order and close lattice match to GaN, it is also being developed as a substrate material for GaN epitaxy. However, the surface finish of the ZnO is such that much of the damage induced by sawing and follow up mechanical polishing remains. We developed a thermal treatment method to eliminate surface damage on the 0 face of ZnO (0 0 0 1) to prepare it for epitaxial growth. Atomic force microscopy images of ZnO (0 0 0 1) annealed at 1050 °C for 3 h etc. show that residual scratches from mechanical polishing are removed and atomically flat, terrace-like surfaces are attained. In addition, low-temperature photoluminescence and high-resolution X-ray diffraction measurements have been employed to investigate the effect of annealing on ZnO substrates.     

Crude-oil price volatility and agricultural employment in the USA

This study begins by asking whether fluctuations in the price of crude oil have affected agricultural employment in the USA. After reviewing previous assessments of the issue, the existence of an empirical relationship between agricultural employment and crude-oil price volatility is established using Granger causality. Subsequently, the nature of the relationship is estimated with the results suggesting that at least three full years are required before the measurable impacts of a percentage change in the real price of crude oil on the change in agricultural employment are exhausted. Finally, the structural stability of the functional relationship between the change in agricultural employment and the volatility of the price of crude oil, the percentage changes in expected net farm income, realized technological innovation, and the wage rate are examined.     

Effect of alkyl chain length on the electrochemical perfluorination of n-alkane (C6–C10) carboxylic acid chlorides

Electrochemical perfluorination (ECPF) of n-hexanoyl, n-heptanoyl, n-octanoyl, n-nonanoyl and n-decanoyl chlorides was carried out under identical experimental conditions in liquid HF. The product distribution among perfluorinated carboxylic acids, perfluoro ethers, perfluoroalkanes, isomerised and fragmented products containing less number of carbon atoms was identified using ¹⁹F NMR. The selectivity of C₆–C₁₀ perfluoro carboxylic acid varied between 29 and 36%. The alkali insoluble perfluoro cyclic ether and perfluoro alkane fractions increased with increasing chain length. The increase of perfluoroalkane fractions is mainly due to decarboxylation. Cyclic ether fractions also decreased slightly with increase in chain length. Among the cyclic ethers α substituted oxolanes were the predominant products. Six membered cyclic ethers were always found to contain β substitution. The possible pathways for these products are also indicated. An erratum to this article can be found at     

Matching treatment focus to patient social investment and support: 18-month follow-up results.

Patients were randomly assigned to 1 of 3 treatments: brief broad-spectrum (BBS), extended relationship enhancement (ERE), or extended cognitive–behavioral (ECB). A hierarchical latent growth model was used to analyze the data of 188 patients (82%) followed for 18 months. ERE treatment was significantly more effective in increasing abstinence of patients entering treatment with a network unsupportive of abstinence or with a low level of investment in their network, whereas BBS treatment was more effective for patients with either (a) both a social network unsupportive of abstinence and a low level of network investment or (b) high investment in a network supportive of abstinence. ECB outcomes were neither as good as those matched nor as bad as those mismatched to the different exposures of relationship enhancement. This suggests that dose of relationship enhancement should be determined after assessing patient relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PACAP-38 in Acute ST-Segment Elevation Myocardial Infarction in Humans and Pigs: A Translational Study

Acute myocardial infarction (MI) is one of the most common causes of death worldwide. Pituitary adenylate cyclase activating polypeptide (PACAP) is a cardioprotective neuropeptide expressing its receptors in the cardiovascular system. The aim of our study was to examine tissue PACAP-38 in a translational porcine MI model and plasma PACAP-38 levels in patients with ST-segment elevation myocardial infarction (STEMI). Significantly lower PACAP-38 levels were detected in the non-ischemic region of the left ventricle (LV) in MI heart compared to the ischemic region of MI-LV and also to the Sham-operated LV in porcine MI model. In STEMI patients, plasma PACAP-38 level was significantly higher before percutaneous coronary intervention (PCI) compared to controls, and decreased after PCI. Significant negative correlation was found between plasma PACAP-38 and troponin levels. Furthermore, a significant effect was revealed between plasma PACAP-38, hypertension and HbA1c levels. This was the first study showing significant changes in cardiac tissue PACAP levels in a porcine MI model and plasma PACAP levels in STEMI patients. These results suggest that PACAP, due to its cardioprotective effects, may play a regulatory role in MI and could be a potential biomarker or drug target in MI.     

Electrochemical behaviour of Mn3+/Mn2+, Co3+/Co2+ and Ce4+/Ce4+ redox mediators in methanesulfonic acid

The redox behaviour of Mn³⁺/Mn²⁺, Co³⁺/Co²⁺ and Ce⁴⁺/Ce³⁺ mediators commonly used in indirect oxidation of organic compounds were evaluated in methane sulfonic acid on a glassy carbon working electrode employing cyclic voltammetry. Manganic methanesulfonate exhibits higher instability in dilute methanesulfonic acid. The solid MnO₂ formed during disproportionation on the glassy carbon electrode further affects the reproducibility. Cobaltic methanesulfonate formation occurs only at oxygen evolution region rendering the overall oxidation process less efficient. Ceric methane sulfonate formation is highly efficient over a wide acid concentration range. Ceric methanesulfonate can also be employed over a wide temperature range to oxidize different aromatic compounds.