The Construction of Minimal DNA Expressions

We describe a formal language/notation for DNA molecules that may contain nicks and gaps. The elements of the language, DNA expressions, denote formal DNA molecules. Different DNA expressions may denote the same formal DNA molecule. We analyse the shortest DNA expressions denoting a given formal DNA molecule. We determine lower bounds on their lengths and explain how we construct these minimal DNA expressions.     

Brake wear from vehicles as an important source of diffuse copper pollution.

In this article we show that brake wear from road traffic vehicles is an important source of atmospheric (particulate) copper concentrations in Europe. Consequently, brake wear also contributes significantly to deposition fluxes of copper to surface waters. We estimated the copper emission due to brake wear to be 2.4 kiloton per year. For comparison, the official database for Europe (without brake wear) totals 2.6 kiloton per year. In Western Europe the brake wear emissions dominate the total emission of copper. Using the spatially resolved emission data, copper distributions over Europe were calculated with the LOTOS-EUROS model. Without brake wear the model underestimates observed copper concentrations by a factor of 3, which is in accordance with other studies. Including the brake wear emissions largely removes the bias. We find that 75% of the atmospheric copper input in the North Sea may be due to brake wear. We estimate that about 25% of the total copper input in the Dutch part of the North Sea stems from brake wear. Although the estimated brake wear copper emission is associated with a large uncertainty, it significantly improves our understanding of the copper cycle in the environment.     

Microprocessor testability

As the level of microprocessor complexity increases to several hundred thousand transistors for a single-chip machine, it is becoming very difficult to test commercially available designs to the level of fault coverage desired by some customers. In order to achieve near 100-percent coverage of single stuck-at faults, future microprocessors must be designed with special testing features (designed for testability). The authors describe the testing problem for microprocessors, including the various methods of generating test sets and their application by the user. A survey of the testability features of some of today's commercially available microprocessors is presented. Suggestions for testability features for future-generation microprocessors are also discussed     

IPv6 delay and loss performance evolution

Although packet delay and loss are two important parameters of the Internet performance, to the best of our knowledge, the evolution of large‐scale IPv6 delay and loss performance has previously not been studied. In this paper, we analyze more than 600 end‐to‐end IPv6 paths between about 26 testboxes of RIPE Network Coordination Centre over two years, and compare the delay and loss performance over time with their IPv4 counterparts. We present and discuss the measurement methodologies and show that IPv6 paths have a higher delay and loss than their IPv4 counterparts. The main reason for the worse performance stems from IPv6‐in‐IPv4 tunnels rather than from native IPv6 paths and such tunnels are still widely used today. Copyright © 2007 John Wiley & Sons, Ltd.     

A Radiation Imaging Detector Made by Postprocessing a Standard CMOS Chip

An unpackaged microchip is used as the sensing element in a miniaturized gaseous proportional chamber. This letter reports on the fabrication and performance of a complete radiation imaging detector based on this principle. Our fabrication schemes are based on wafer-scale and chip-scale postprocessing. Compared to hybrid-assembled gaseous detectors, our microsystem shows superior alignment precision and energy resolution, and offers the capability to unambiguously reconstruct 3D radiation tracks on the spot.     

What's the use of being happy? Mood states, useful objects, and repetition priming effects.

Two experiments involving 99 undergraduate participants sought to examine the influence of mood states on encoding speed within lexical decision and pronunciation tasks. Mood states were measured naturalistically in Experiment 1 and manipulated in Experiment 2. Stimuli consisted of nouns representing useful (e.g., food) and nonuseful (e.g., lint) objects. Mood states had no implications for initial encoding speed. However, when the same words were presented a 2nd time (i.e., repeated), happy individuals displayed a tendency to encode useful words faster than nonuseful ones. Thus, mood states influenced repetition priming on the basis of stimulus valence. The authors propose that happiness sensitizes individuals to useful or rewarding objects, which in turn creates a stronger memory trace for such stimuli in the future. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of Production Process Parameters on Fish Oil Quality in a Pilot Plant

ABSTRACT: A pilot plant used for upgrading herring byproducts into fish oil was analyzed on its operational efficiency and product quality. The temperature of the heat exchanger and the speeds of the pump and the 3-phase decanter were varied according to a 2³ fractional factorial design. The initial amount of oxidation products present in the crude oil, its storage stability, and the yields from the different obtained products were determined. Multivariate data analysis of the advanced screening stage showed that T had neither influence on the quality nor on the yield in contrast to D and MP (P < 0.05). Process optimization results showed that the quality of the oil was influenced by an interaction effect between the speed of the MP and the D. Oils processed with the highest MP speed were the most stable during storage.     

Hemodialysis in the United Kingdom

Hemodialysis was a neglected aspect of nephrology in the UK. At the request of the Renal Association, the first UK Haemodialysis Masterclass was organized in 2007. The articles in this supplement arose from that meeting. Here, an overview of UK hemodialysis services and nephrology training is presented as background. Government‐funded dialysis should be provided to all UK citizens who require it. In 2005, there were 17,645 patients receiving hemodialysis, 5057 on peritoneal dialysis and 19,074 with kidney transplants, looked after by 359 nephrologists working in 73 National Health Service renal units. Renal replacement therapy incidence and prevalence remain comparatively low, at 108 and 694 per million population, respectively. Whether this represents inadequate provision or genuinely lower need remains unclear. The Renal Association sets clinical practice guidelines for dialysis, and audits performance via the UK Renal Registry. Postgraduate medical education is undergoing radical change in the UK. This is driven by the reduction in trainee doctors' working hours to 48 hr/week (mandated by the European Working Time Directive), and the governments' wish to reduce the duration of training, but also by a desire to formalize training, Our challenge is to continue to produce talented clinical nephrologists educated in breadth and depth, despite the reduced emphasis on clinical experience and omission of period of scientific research. The future for hemodialysis services in the UK is, however, promising with an expansion in the number of specialists and dialysis centers, and a growing interest in dialysis practice and research.