Electoral system reviews in New Zealand, Britain and Canada: a critical comparison

This article compares the use of people outside government to consider electoral reform in three countries using the single-member plurality electoral system. The composition of electoral reform bodies, ranging from commissions of experts (New Zealand) and ex- politicians (Britain) to assemblies of randomly selected citizens (British Columbia), appears to have influenced how well their recommendations were received by the public. Governments should be careful not to assume that they can retain control of the electoral reform process once they let it out of their hands, as the cases of New Zealand and British Columbia show, where majorities of the voters chose reform

The effects of toxic pollutants on freshwater bacterial communities

The effects of heavy metals, and phenolic compounds and phenol derivatives, on freshwater bacterial communities was studied. An effluent containing copper, zinc, cadmium and lead was found to have little or no toxic effect on planktonic bacterial communities in the River Aire, except for a localised inhibition of bacterial heterotrophic activity immediately below the discharge. The rapid complexation, adsorption and dilution of metals in the river were thought to account for the absence of bacterial inhibition.The presence of phenolic compounds and phenol derivatives in a small stream, Sugden Beck, caused major alteration in the planktonic and sediment bacterial communities, although this depended on pH. I.n comparison with a control stream, Stubs Beck, which did not contain phenolic compounds or phenol derivatives, the bacterial community in Sugden Beck had fewer percentage chromogenic bacteria, reduced species diversity and increased viable counts on Pseudomonas-selective-media (PSM agar). A taxonomic study at these two sites showed that the phenolic compounds and phenol derivative~ in Sugden Beck, caused a shift in species composition away from a diverse bacterial community, containing a wide range of Gram-negative and Gram-positive genera, to one comprised of Gram-negative bacteria belonging to the genus Pseudomonas. Major differences were also found between Sugden Beck and Stubs Beck, in the morphology of planktonic bacteria and the ability to mineralize 2,4-dichlorophenoxyacetic acid (2,4D). Bacteria isolated from Stubs Beck and Sugden Beck were shown to have differing sensitivities to phenolic compounds and phenol derivatives. The toxicity of these compounds to bacteria was found to depend on the compound's structure and also on pH

Determination of the effects of GPS failures on aviation applications

Imperial Users onl

Bayesian Inference of GNSS Failures

International audienceThe probability of failure (failure rate) is a key input parameter to integrity monitoring systems used for safety, liability or mission critical applications. A standard approach in the design of Global Positioning System (GPS) integrity monitoring is to utilize the service commitment on the probability of major service failure, often by applying a conservative factor. This paper addresses the question of what factor is appropriate by applying Bayesian inference to real and hypothetical fault histories. Global Navigation Satellite System (GNSS) anomalies include clock or signal transmission type faults which are punctual (may occur at any time) and incorrect ephemeris data which are broadcast for a nominal two hours. These two types of anomaly, classified as continuous and discrete respectively are addressed. Bounds on the total probability of failure are obtained with given confidence levels subject to well defined hypotheses relating past to future performance. Factors for the GPS service commitment of 10-5 per hour per satellite are obtained within the range two to five with high confidence (up to 1-10-9)

Simplified GNSS Fusion-based Train Positioning System and its Diagnosis

International audienceIn this paper, two simple GNSS-based positioning methods are proposed and their diagnostic functions for GNSS failure are tested. Firstly, the odometer-based method, which are proposed in our previous research [1], is concretized to be implemented for general cases. This method detects faults in the GNSS solution due to satellite failure or local effects using both odometry and track geometry of the onboard system. It enables to monitor all three-dimensional solution error so that higher sensitivity for the fault detection can be achieved. Secondly, single-axis accelerometer-based approach is newly proposed. Positioning architecture of this method is designed in traveling distance domain with the configuration of single-axis accelerometer installed along the forward direction. The diagnosis of GNSS signal can be done easily in one-dimensional space. Therefore, the latter method is expected to give greater sensitivity to detect GNSS failures while maintaining a relatively simple architecture. Both methods are tested in simulation, and their abilities for detecting fault in GNSS signal are investigated and compared

Assessment of Dual-frequency Signal Quality Monitor to Support CAT II/III GBAS

International audienceThis paper assesses the performance of the signal quality monitors for the Ground-Based Augmentation System (GBAS) which supports Category (CAT) II and III precision approach. Three types of monitors are used for signal deformation faults: Honeywell signal quality monitor (SQM), ENAC Code-Carrier Divergence (CCD) monitor and a proposed Divergence-Free (DF)-Innovation monitor. The existing Honeywell SQM and ENAC CCD monitors have some response time due to the smoothing filter used for their metrics. Consequently, the performance of those monitors is limited right after the fault onset. To improve the monitor performance in this time period, the DF-Innovation monitor has been proposed. The performance of the monitors has been assessed by comparing the minimum value of the probabilities of missed detection of three monitors and the required probability of missed detection according to the differential range error, which is defined in the standard document. As a result, for GBAS Approach Service Types (GAST) F, the probability of missed detection of the monitor was compliant with respect to the requirements for all fault cases and receiver configurations, for GPS L1/L5 and Galileo E1/E5. In addition, we observed that the proposed DF-Innovation monitor is effective in reducing time delay, which is the required time at airborne from filter initialization time to the time when the airborne user incorporates the measurement and correction for navigation. To be more specific, the use of the proposed monitor can reduce the time delay by 80% compared to the case without using the proposed monitor, and moreover, it can even reduce the value of time delay below 50 second, which is the recommended value currently

Nuclear Localization of HBD-1 in Human Keratinocytes

Objective: Human defensins and cathelicidins are a family of cationic antimicrobial peptides (AMPs), which play multiple roles in both innate and adaptive immune systems. They have direct antimicrobial activity against several microorganisms including burn pathogens. The majority of components of innate and adaptive immunity either express naturally occurring defensins or are otherwise chemoattracted or functionally affected by them. They also enhance adaptive immunity and wound healing and alter antibody production. All mechanisms to explain multiple functions of AMPs are not clearly understood. Prior studies to localize defensins in normal and burned skin using deconvolution fluorescence scanning microscopy indicate localization of defensins in the nucleus, perinuclear regions, and cytoplasm. The objective of this study is to further confirm the identification of HBD-1 in the nucleus by deconvolution microscopic studies involving image reconstruction and wire frame modeling. Results: Our study demonstrated the presence of intranuclear HBD-1 in keratinocytes throughout the stratum spinosum by costaining with the nuclear probe DAPI. In addition, HBD-1 sequence does show some homology with known cationic nuclear localization signal sequences. Conclusion: To our knowledge, this is the first report to localize HBD-1 in the nuclear region, suggesting a role for this peptide in gene expression and providing new data that may help determine mechanisms of defensin functions