FUNCTIONAL PEARL : lazy wheel sieves and spirals of primes

The popular method of enumerating the primes is the Sieve of Eratosthenes. It can be programmed very neatly in a lazy functional language, but runs rather slowly. A little-known alternative method is the Wheel Sieve, originally formulated as a fast imperative algorithm for obtaining all primes up to a given limit, assuming destructive access to a bit-array. This article describes functional variants of the wheel sieve that enumerate all primes as a lazy list

Inductive benchmarking for purely functional data structures

Every designer of a new data structure wants to know how well it performs in comparison with others. But finding, coding and testing applications as benchmarks can be tedious and time-consuming. Besides, how a benchmark uses a data structure may considerably affect its apparent efficiency, so the choice of applications may bias the results. We address these problems by developing a tool for inductive benchmarking. This tool, Auburn, can generate benchmarks across a wide distribution of uses. We precisely define 'the use of a data structure', upon which we build the core algorithms of Auburn: how to generate a benchmark from a description of use, and how to extract a description of use from an application. We then apply inductive classification techniques to obtain decision trees for the choice between competing data structures. We test Auburn by benchmarking several implementations of three common data structures: queues, random-access lists and heaps. These and other results show Auburn to be a useful and accurate tool, but they also reveal some limitations of the approach

Challenging workplace inequality : precarious workers’ institutional and associational power in Gauteng, South Africa

Abstract: The world of work has been reorganised, the numbers of workers employed through the standard employment relationship has declined and there has been an increase in non-standard employment: labour broking, outsourcing and other forms of precarious and temporary work. This has created highly unequal workplaces where atypical workers perform the same work as permanent workers for often half the wages of what a permanent worker receives. This article considers how precarious workers are organising, outside of trade unions, to fight against workplace inequality to gain rights to permanent work. This article develops the power resource approach (PRA) as a lens through which to explore how labour broker workers are organising in Gauteng. Through the analysis of two workplace case studies, the article examines how amendments to the Labour Relations Act (LRA) in 2015 provided new rights and a new avenue through which precarious workers could organise. The case studies illustrate the dynamic interactions between institutional and associational power, an often overlooked relationship , and demonstrate the multiple avenues through which precarious workers mobilise their power to fight against inequality

Forage shrubs and grasses for revegetating saltland

Salt tolerant shrubs and grasses are used for forage production from salt-affected farmland. This Bulletin is designed to assist in recognition of the important species in Western Australia and to provide information on their use. The species listed have more forage value than some natural indicators and colonizers of saltland, such as Mediterranean barley grass (Hordeum geniculatum), ice plant (Mesembryanthemum spp.), mallee lovegrass (Eragrostisdielsii), salt spurry (Spergularia spp.), curly ryegrass (Parapholis incurva) and beard grass (Polypogon monspeliensis). Some of the plants are also useful for rehabilitating degraded rangeland and mine dumps in arid areas.https://researchlibrary.agric.wa.gov.au/bulletins/1100/thumbnail.jp

Effects of Hydrogen on the Phases and Transition Temperatures of NiTi

Austenitic (B2) NiTi samples were cathodically charged with various amounts of hydrogen. Trends are tracked based on temperature, time and voltage throughout the process to establish consistent and predictive hydrogen charging procedures. The effect of hydrogen on the austenitic structure and the formation of hydrides are studied with x-ray diffraction (XRD). An increase in the austenite lattice parameter with increased hydrogen content is observed up to a hydrogen solubility limit of approximately 85 wppm. At greater hydrogen concentrations, additional XRD peaks appear, suggesting possible hydride formation. Differential scanning calorimetry (DSC) results show a decrease in both the austenitic and martensitic transition temperatures with increased atomic hydrogen content and increased hydride phase. Scanning electron microscopy (SEM) is used to reveal the hydride phase. The effect of atomic hydrogen on NiTi and the structure of the hydride phase are compared with previous hydrogen studies

Detecting anomalous energy consumption in android applications

The use of powerful mobile devices, like smartphones, tablets and laptops, are changing the way programmers develop software. While in the past the primary goal to optimize software was the run time optimization, nowadays there is a growing awareness of the need to reduce energy consumption. This paper presents a technique and a tool to detect anomalous energy consumption in Android applications, and to relate it directly with the source code of the application. We propose a dynamically calibrated model for energy consumption for the Android ecosystem, and that supports different devices. The model is then used as an API to monitor the application execution: first, we instrument the application source code so that we can relate energy consumption to the application source code; second, we use a statistical approach, based on fault-localization techniques, to localize abnormal energy consumption in the source code

Lumen shape reconstruction using a soft robotic balloon catheter and electrical impedance tomography

Incorrectly sized balloon catheters can lead to increased post-surgical complications, yet even with preoperative imaging, correct selection remains a challenge. With limited feedback during surgery, it is difficult to verify correct deployment. We propose the use of integrated impedance measurements and Electrical Impedance Tomography (EIT) imaging to assess the deformation of the balloon and determine the size and shape of the surrounding lumen. Previous work using single impedance measurements, or pressure data and analytical models, whilst demonstrating high sizing accuracy, have assumed a circular cross section. Here we extend these methods by adding a multitude of electrodes to detect elliptical and occluded lumen and obtain EIT images to localise deformations. Using a 14 Fr (5.3 mm) catheter as an example, numerical simulations were performed to find the optimal electrode configuration of two rings of 8 electrodes spaced 10 mm apart. The simulations predicted that the maximum detectable aspect ratio decreased from 0.9 for a 14mm balloon to 0.5 at 30mm. The sizing and ellipticity detection results were verified experimentally. A prototype robotic balloon catheter was constructed to automatically inflate a compliant balloon while simultaneously recording EIT and pressure data. Data were collected in experiments replicating stenotic vessels with an elliptical and asymmetrical profile, and the widening of a lumen during angioplasty. After calibration, the system was able to correctly localise the occlusion and detect aspect ratios of 0.75. EIT images further localised the occlusion and visualised the dilation of the lumen during balloon inflation

What unites Europe and what divides it? Solidarity and the European heritage reconsidered

Despite the on-set on new divisions, there is a strong case to be made for the view that ultimately Europe is more united than divided. There is still significant continuity with the post-war project of reconstruction and peace and that this common ground that constitutes the European heritage needs to be given greater recognition. One of the defining features of European self-understanding is opposition to war

Measuring change in vulnerable adolescents: Findings from a peer education evaluation in South Africa

Introduction: In the context of poverty and HIV and AIDS, peer education is thought to be capable of providing vulnerable youth with psychosocial support as well as information and decision-making skills otherwise limited by scarce social and material resources. As a preventative education intervention method, peer education is a strategy aimed at norms and peer group influences that affect health behaviours and attitudes. However, too few evaluations of peer-led programmes are available,and they frequently fail to reflect real differences between those who have been recipients of peer education and those who have not. This article reports on an evaluation of a pilot peer-led intervention, entitled Vhutshilo, implemented on principles agreed upon through a collaborative effort in South Africa by the Harvard School of Public Health and the Centre for theSupport of Peer Education (the Rutanang collaboration). Vhutshilo targeted vulnerable adolescents aged 14–16 years living in some of South Africa’s under-resourced communities. Methodology: The research design was a mixed-method (qualitative and quantitative), longitudinal, quasi-experimental evaluation. Tools used included a quantitative survey questionnaire (n ¼ 183) and semi-structured interviews (n ¼ 32) with beneficiaries of peer education. Surveys were administered twice forbeneficiaries of peer education (n ¼ 73), immediately after completion of the programme (post-test) and 4 months later (delayed post-test), and once for control group members (n ¼ 110). The three main  methodological limitations in this study were the use of a once-off control group assessment as the baseline for comparison, without a pre-test, due to timing and resource constraints; a small sample size (n ¼ 183), which reduced the statistical power of the evaluation; and the unavailability of existing tested survey questions to measure the impact of peer education and its role in behaviour change. Findings: This article reports on the difficulties of designing a comprehensive evaluation within time and financial constraints, critically evaluates survey design with multi-item indicators, and discusses six statistically significant changes observed in Vhutshilo participants out of a 92-point survey. Youth struggling with poor quality education and living in economically fraught contexts with little social support, nonetheless, showed evidence of having greater knowledge of support networks and an expanded emotional repertoire by the end of the Vhutshilo programme, and 4 months later. At both individual and group level, many with low socio-economic status showed great improvement with regard to programme indicator scores. Conclusion: For the poorest adolescents, especially those living in the rural parts of South Africa, peer education has the potential to change future orientation, attitudes and knowledge regarding HIV and AIDS, including an intolerance for multiple concurrent partnerships. When well organised and properly supported, peer education programmes (and the Vhutshilo curriculum, in particular) provide vulnerable youth with opportunities to develop  psychosocial skills and informational resources that contribute to the changing of norms, attitudes and behaviours. However, the article also flags the need for effective peer education evaluations that take into account limited financial resources and that possess tested indicators of programme effectiveness

Who is to blame? The relationship between ingroup identification and relative deprivation is moderated by ingroup attributions

Contradictory evidence can be found in the literature about whether ingroup identification and perceived relative deprivation are positively or negatively related. Indeed, theoretical arguments can be made for both effects. It was proposed that the contradictory findings can be explained by considering a hitherto unstudied moderator: The extent to which deprivation is attributed to the ingroup. It was hypothesised that identification would only have a negative impact on deprivation, and that deprivation would only have a negative impact on identification, if ingroup attributions are high. To test this, attributions to the ingroup were experimentally manipulated among British student participants (N = 189) who were asked about their perceived deprivation vis-à-vis German students, yield ing support for the hypotheses