Regulation and redistribution in utilities

The consumption of utilities (for example, energy and water), along with that of other goods such as food, clothing, shelter, health and education, is often thought of as something that has particular distributional significance. This concern is reflected by the range of welfare and regulatory measures in place that are designed to guard against non-participation or under-consumption. The pricing of these goods illustrates well the conflicting arguments between economic efficiency and equity. The case for charging VAT on fuel, for example, is essentially an efficiency argument which points to the distortionary effects of a tax system that increases the prices of some goods (for example, double-glazing) and not of others (for example, domestic energy). The counter-argument is based upon notions of equity: that it is unfair to tax a necessity because the effects fall hardest on the living standards of poor households.

Precision placement of fertiliser for optimising the early nutrition of vegetable crops : a review of the implications for the yield and quality of crops, and their nutrient use efficiency

The research outlined in this paper highlights the importance of the early nutrition of vegetable crops, and its long-term effects on their subsequent growth and development. Results are also presented to demonstrate how the nutrient supply during the establishment stages of young seedlings and transplants can be enhanced by targeting fertiliser to a zone close to their developing roots. Three different precision fertiliser placement techniques are compared for this purpose: starter, band or side-injected fertiliser. The use of each of these methods consistently produced the same (or greater) yields at lower application rates than those from conventional broadcast applications, increasing the apparent recovery of N, P and K, and the overall efficiency of nutrient use, while reducing the levels of residual nutrients in the soil. Starter fertilisers also advanced the maturity of some crops, and enhanced produce quality by increasing the proportions of the larger and/or more desirable marketable grades. The benefits of the different placement techniques are illustrated with selected examples from research at Warwick HRI using different vegetable crops, including lettuce, onion and carrot

Identifying invertebrate invasions using morphological and molecular analyses: North American Daphnia ‘pulex’ in New Zealand fresh waters

We used a DNA barcoding approach to identify specimens of the Daphnia pulex complex occurring in New Zealand lakes, documenting the establishment of non-indigenous North American Daphnia 'pulex'. Morphological delineation of species in this complex is problematic due to a lack of good morphological traits to distinguish the species, as there is a relatively high degree of morphological stasis within the group through evolutionary time. Accordingly, genetic analyses were used to determine the specific identity and likely geographic origin of this species. Morphologically, individuals most closely resembled Daphnia pulicaria or Daphnia pulex sensu lato, which cannot be separated morphologically. Furthermore, each of these taxa comprises separate species in North America and Europe, despite carrying the same names. We identified individuals using a 658 bp nucleotide portion of the mitochondrial cytochrome c oxidase subunit 1 gene (COI) as North American Daphnia 'pulex', being distinct from European Daphnia pulex sensu stricto and D. pulicaria from Europe or North America. Cellulose allozyme electrophoresis was used to confirm that individuals were not hybrids with D. pulicaria. North American Daphnia 'pulex' in New Zealand were first recorded in New Zealand from South Island lakes that are popular for overseas recreational fishers, indicating a possible source of introduction for this species (e.g. on/in fishing gear). Our study provides an additional example of how genetic techniques can be used for the accurate identification of non-indigenous taxa, particularly when morphological species determination is not possible. The growth of global databases such as GenBank and Barcode of Life Datasystems (BOLD) will further enhance this identification capacity

Two novel flight-interception trap designs for low-cost forest insect surveys

This paper introduces two passive trap designs for the survey of flying Coleoptera and other insects which can be constructed on very low budgets at < £1 per trap. A trunk window trap and an aerial flight-interception trap are presented, based on commonly used designs, but using much cheaper materials than standard. Construction diagrams are given, along with a description of trap installation, operation and beetle species found using these methods during a survey of Ayr Gorge Woodland, South-West Scotland. The traps were found to be robust and easy to operate. It is hoped that these trap designs will be of use to charitable organisations, students and amateurs who may previously have been unable to consider monitoring flying insects at large scales due to the prohibitive cost of equipment

ChromaStarPy: A stellar atmosphere and spectrum modeling and visualization lab in python

We announce ChromaStarPy, an integrated general stellar atmospheric modeling and spectrum synthesis code written entirely in python V. 3. ChromaStarPy is a direct port of the ChromaStarServer (CSServ) Java modeling code described in earlier papers in this series, and many of the associated JavaScript (JS) post-processing procedures have been ported and incorporated into CSPy so that students have access to ready-made "data products". A python integrated development environment (IDE) allows a student in a more advanced course to experiment with the code and to graphically visualize intermediate and final results, ad hoc, as they are running it. CSPy allows students and researchers to compare modeled to observed spectra in the same IDE in which they are processing observational data, while having complete control over the stellar parameters affecting the synthetic spectra. We also take the opportunity to describe improvements that have been made to the related codes, ChromaStar (CS), CSServ and ChromaStarDB (CSDB) that, where relevant, have also been incorporated into CSPy. The application may be found at the home page of the OpenStars project: http://www.ap.smu.ca/~ishort/OpenStars/ .Comment: See DOI zenodo.1095687. Accepted for publication in The Astrophysical Journa

Nitrate pollution from horticultural production systems : tools for policy and advice from field to catchment scales

The implementation of the Nitrates Directive has imposed a requirement to restrict N fertiliser and manuring practices on farms across the EU in order to reduce nitrate losses to water. These requirements have since been extended by the more demanding Water Framework Directive, which broadens the focus from the control of farm practices to a consideration of the impacts of pollutants from all sources on water quality at a catchment or larger scale. Together, these Directives set limits for water quality, and identify general strategies for how these might be achieved. However, it is the responsibility of policy makers in each Nation State to design the details of the management practices and environmental protection measures required to meet the objectives of the legislation, to ensure they are appropriate for their specific types of land use and climate. This paper describes various modelling tools for comparing different cropping and land use strategies, and illustrates with examples how they can inform policy makers about the environmental benefits of changing management practices and how to prioritise them. The results can help to provide the specific advice on N fertiliser and land use management required by farmers and growers at a field scale, and by environmental managers at a catchment or larger scale. A further example of how results from multiple catchments can be up-scaled and compared using Geographic Information Systems is also outlined

A Survey of Research into Mixed Criticality Systems

This survey covers research into mixed criticality systems that has been published since Vestal’s seminal paper in 2007, up until the end of 2016. The survey is organised along the lines of the major research areas within this topic. These include single processor analysis (including fixed priority and EDF scheduling, shared resources and static and synchronous scheduling), multiprocessor analysis, realistic models, and systems issues. The survey also explores the relationship between research into mixed criticality systems and other topics such as hard and soft time constraints, fault tolerant scheduling, hierarchical scheduling, cyber physical systems, probabilistic real-time systems, and industrial safety standards

Response Time Analysis for Mixed Criticality Systems with Arbitrary Deadlines

This paper extends analysis of the Adaptive Mixed Criticality (AMC) scheme for fixed-priority preemptive scheduling of mixed-criticality systems to include tasks with arbitrary deadlines. Both of the previously published schedulability tests, AMC-rtb and AMC-max are extended to cater for tasks with deadlines that may be greater than their periods. Evaluations show that the simpler method, AMC-rtb-Arb, remains a viable approach that performs almost as well as the more complex alternative, AMC-max-Arb, when tasks with arbitrary deadlines are considered

Schedulability Analysis for Adaptive Mixed Criticality Systems with Arbitrary Deadlines and Semi-Clairvoyance

This paper provides analysis of the Adaptive Mixed Criticality (AMC) scheduling scheme for mixed-criticality systems that include tasks with arbitrary deadlines and semi-clairvoyant behavior. An arbitrary deadline task is one that can have a deadline that may be greater than its period. A semi-clairvoyant task is one that upon arrival of each job, reveals which of its two WCET parameters will be respected. This enables an earlier switch to be made from the normal mode of operation to the abnormal mode. The previously published schedulability test AMC-max is modified to cater for both of these extensions. Evaluation shows that there is a significant improvement in schedulability for semi-clairvoyant tasks over non-clairvoyant, and for arbitrary-deadline tasks over considering those deadlines as being constrained by the task’s period

Deriving specifications of control programs for cyber physical systems

Cyber Physical Systems (CPS) exist in a physical environment and comprise both physical components and a control program. Physical components are inherently liable to failure and yet an overall CPS is required to operate safely, reliably and cost effectively. This paper proposes a framework for deriving the specification of the software control component of a CPS from an understanding of the behaviour required of the overall system in its physical environment. The two key elements of this framework are (i) an extension to the use of rely/guarantee conditions to allow specifications to be obtained systematically from requirements (as expressed in terms of the required behaviour in the environment) and nested assumptions (about the physical components of the CPS); and (ii) the use of time bands to record the temporal properties required of the CPS at a number of different granularities. The key contribution is in combining these ideas; using time bands overcomes a significant drawback in earlier work. The paper also addresses the means by which the reliability of a CPS can be addressed by challenging each rely condition in the derived specification and, where appropriate, improve robustness and/or define weaker guarantees that can be delivered with respect to the corresponding weaker rely conditions