Linearizability with Ownership Transfer

Linearizability is a commonly accepted notion of correctness for libraries of concurrent algorithms. Unfortunately, it assumes a complete isolation between a library and its client, with interactions limited to passing values of a given data type. This is inappropriate for common programming languages, where libraries and their clients can communicate via the heap, transferring the ownership of data structures, and can even run in a shared address space without any memory protection. In this paper, we present the first definition of linearizability that lifts this limitation and establish an Abstraction Theorem: while proving a property of a client of a concurrent library, we can soundly replace the library by its abstract implementation related to the original one by our generalisation of linearizability. This allows abstracting from the details of the library implementation while reasoning about the client. We also prove that linearizability with ownership transfer can be derived from the classical one if the library does not access some of data structures transferred to it by the client

Learning and research for sustainable agro-ecosystems by both farmers and scientists.

This research explored how farming businesses learn, make decisions, benchmark and carry out their own informal experimentation to find the system that meet their needs and their local ecological context. The research also examined how farming businesses and scientific researchers can collaborate. This required a greater understanding amongst scientists and between scientists and businesses, recognising each other's strengths and weaknesses and finding ways of working together. This interdisciplinary subject will be examined by a team of social, environmental and biological researchers, examining ten cases of farmer researcher collaboration with the aim of identifying good practice in interdisciplinary research on agro ecosystems in UK agriculture

Deep ROSAT-HRI observations of the NGC 1399/NGC 1404 region: morphology and structure of the X-ray halo

We present the analysis of a deep (167 ks) ROSAT HRI observation of the cD galaxy NGC 1399 in the Fornax cluster. Using both HRI and, at larger radii, archival PSPC data, we find that the radial behavior of the X-ray surface brightness profile is not consistent with a simple Beta model and suggests instead three distinct components. We use a multi-component bidimensional model to study in detail these three components that we identify respectively with the cooling flow region, the galactic and the cluster halo. From these data we derive a binding mass distribution in agreement with that suggested by optical dynamical indicators, with an inner core dominated by luminous matter and an extended dark halo differently distributed on galactic and cluster scales. The HRI data and a preliminary analysis of Chandra public data, allow us to detect significant density fluctuations in the halo. We discuss possible non-equilibrium scenarios to explain the hot halo structure, including tidal interactions with neighboring galaxies, ram stripping from the intra-cluster medium and merging events. In the innermost region of NGC 1399, the comparison between the X-ray and radio emission suggests that the radio emitting plasma is displacing and producing shocks in the hot X-ray emitting gas. We found that the NGC 1404 halo is well represented by a single symmetric Beta model and follows the stellar light profile within the inner 8 kpc. The mass distribution is similar to the `central' component of the NGC 1399 halo. At larger radii ram pressure stripping from the intra-cluster medium produces strong asymmetries in the gas distribution. Finally we discuss the properties of the point source population finding evidence of correlation between the source excess and NGC 1399.Comment: 34 pages in aastex5.0 format, including 28 B&W and 4 color figures. Uses LaTex packages: subfigure, lscape and psfig. Accepted for publication in ApJ. High resolution version can be found at: http://www.na.astro.it/~paolillo/publications.htm

Developing a partcipatory approach to seed production and varietal selection

The performance of UK winter wheat varieties was tested under organic conditions involving farmer participation. Three breadmaking varieties (Hereward, Solstice and Xi19) and their mixture (1:1:1) were grown at 19 UK farms in 2003/04 and 2004/05. The variability of productivity on organic farms was illustrated with more variation among farm sites than among varieties. Seed health was generally high over all sites. Although the trials were successful, more time was needed at project initiation to improve farmer involvement. Some farmers expected more researcher visits, and were reticent about assessing the trials themselves. In contrast, some participants valued the variety performance data on their farms particularly when related to that of other growers. The balance between the goals of the researchers relative to the farmers needs to be defined at project initiation

X-ray and Radio Interactions in the Cores of Cooling Flow Clusters

We present high resolution ROSAT x-ray and radio observations of three cooling flow clusters containing steep spectrum radio sources at their cores. All three systems exhibit strong signs of interaction between the radio plasma and the hot intracluster medium. Two clusters, A133 and A2626, show enhanced x-ray emission spatially coincident with the radio source whereas the third cluster, A2052, exhibits a large region of x-ray excess surrounding much of the radio source. Using 3-D numerical simulations, we show that a perturbed jet propagating through a cooling flow atmosphere can give rise to amorphous radio morphologies, particularly in the case where the jet was ``turned off'' and allowed to age passively. In addition, the simulated x-ray surface brightness produced both excesses and deficits as seen observationally.Comment: 25 pages, 10 figures, accepted for publication in A

Children’s services in the age of information technology: What matters most to frontline professionals

Summary The last two decades have seen information systems featuring prominently in calls for the modernisation of the UK social care system. However, critics have maintained that these systems are of limited value to social care professionals whose design and implementation is driven by a preoccupation with performance management and a culture of professional audit and accountability, precepts of 'managerialism'. However, this area of research has often suffered from lack of focus on how technological changes affect public administration and service delivery and often characterises technology as a politically neutral tool detached from its socio-political context whilst also ignoring the strategic predispositions of human service professionals.Findings This research was conducted in three local authorities in England. Using the 'technological affordance' perspective, we contend that the way social workers interact with Integrated Children's System is shaped by the discord between socio-historically evolved professional values epitomising the social work profession and managerialist reforms promoting standardised ways of performing it. Application Integrated Children's System has transformed social work from an art to a technical activity, dominated by unimaginative and routinised working practices. Social workers are becoming peripheral figures and this is where social work needs to be reclaimed. Policymakers need to rethink taken for granted assumptions that practitioners would replace their professional expertise with technology and realise that the effective use of Integrated Children's System depends on bureau-professionalised judgements of social workers. Whilst specific patterns of technology usage can be developed and institutionalised, real objectives of children's social services should not be sacrificed

A participatory methodology for large scale field trials in the UK

Farmer participation was essential in developing a uniquely useful set of wheat variety trials data on a wide range of organic farms over two years. Although the trials were successful, it became clear that some of the participating farmers felt there were some limitations in the process. These included a lack of ownership in the project and a concern for more researcher help. It was clear that a greater time in-vestment was needed at the start of the project to help with farmer understanding and ownership. De-spite the negative comments, farmers appreciated their involvement, particularly in contrasting their own views and information with that from the wider scene. Farmer participation is essential for systems-level research and this project helped to develop a small core of trained farmers and researchers

Reducing green tape or rolling back IA in Australia: What are found jurisdictions up to?

EIA has been practiced in Australia and the rest of the world for over 40 years, but despite its successes, EIA may now be facing its biggest challenge since it came into being in 1970 with the US National Environmental Policy Act. As Morgan (2012, 11) notes: “As governments look to stimulate economic growth and create employment in response to the current financial crisis, many are promoting a major expansion of physical infrastructure, encouraging resource development projects, and generally seeking to speed decision-making about development projects. Both EIA and SEA should be even more important in such circumstances, yet the moves taken in some countries to speed up decision-making may weaken the provisions for environmental protection, including impact assessment.” In this political and economic environment, EIA is under scrutiny. Proposed changes to the EU directive on EIA released in October 2012 contain ten changes to the Articles of the Directive, with six of these referring to either ‘streamlining’ EIA or introducing specific timeframes for parts of the EIA process (European Commission 2012). This scrutiny has not been restricted to economies in recession, but includes those that have avoided recession because of strong resources sectors. The same appears to be happening in Australia, and this paper reports on these and other possible ‘efficiency’ changes to EIA in Australia at both national and sub-national levels. We attempt to critically examine the nature of such changes and the risks that may be associated with their implementation. Changes to three of the sub-national EIA processes are reviewed in detail, as well as the proposed changes to the national EIA process. There is always room for more timely assessments, but a critical examination of the potential consequences of these “reforms” on the conduct of EIAs is needed, including whether these efficiency changes will deliver sound environmental management and sustainability-oriented decision-making

Formation of cavities in the X-ray emitting cluster gas of Cygnus A

Publisher's version/PDFThe ROSAT data from the cluster gas of Cygnus A are re-examined in light of a three-dimensional hydrodynamic simulation of a supersonic jet propagating in an isothermal King atmosphere designed to follow the observed density distribution of the Cygnus A cluster gas. In addition to the presence of a non-uniform atmosphere, this simulation departs from previous 3D work in that the X-ray (bremsstrahlung) brightness distribution has been determined from the flow variables as a function of time. This simulation provides compelling evidence for the conclusions reached by Carilli et al. who stated that the major features of the X-ray brightness distribution are manifestations of the expanding lobe and the passage of a bow shock within the atmosphere. Further, this work demonstrates that these X-ray features are as much a function of the observing frequency and bandwidth as they are of the local conditions in the cluster gas of Cygnus A. In addition, new estimates of the Mach number of the jet (M[greater than or equal to]4) as well as the density and temperature jumps across the bow shock are derived by comparing the simulations with the X-ray data from Cygnus A

Desperate housewives: An analysis of the characterisations of female gamblers portrayed in gambling movies in Hong Kong

This article examines portrayals of female gamblers in recent Hong Kong movies. The authors report that the depiction of female gamblers is very different from that of male gamblers in the movies made in the same period. Whereas the male gamblers are pitching a lonely and desperate battle against the evil opponent, the female gamblers portrayed in the movies are housewives or small-time players who gamble only for their personal gain. A general negative overtone in portrayals of female gamblers was interpreted as a reflection of the traditional view that discourages women from gambling. The shift of gambling themes in the Hong Kong movies has been identified to reflect the most salient concerns among Hong Kong residents. Such changes are attributed to particular social and cultural changes in the community