Design patterns percolating to parallel programming framework implementation

Structured parallel programming is recognised as a viable and effective means of tackling parallel programming problems. Recently, a set of simple and powerful parallel building blocks RISC pb²l) has been proposed to support modelling and implementation of parallel frameworks. In this work we demonstrate how that same parallel building block set may be used to model both general purpose parallel programming abstractions, not usually listed in classical skeleton sets, and more specialized domain specific parallel patterns. We show how an implementation of RISC pb² l can be realised via the FastFlow framework and present experimental evidence of the feasibility and efficiency of the approach.

Autonomic scheduling of tasks from data parallel patterns to CPU/GPU core mixes

We propose a methodology for optimizing the execution of data parallel (sub-)tasks on CPU and GPU cores of the same heterogeneous architecture. The methodology is based on two main components: i) an analytical performance model for scheduling tasks among CPU and GPU cores, such that the global execution time of the overall data parallel pattern is optimized; and ii) an autonomic module which uses the analytical performance model to implement the data parallel computations in a completely autonomic way, requiring no programmer intervention to optimize the computation across CPU and GPU cores. The analytical performance model uses a small set of simple parameters to devise a partitioning-between CPU and GPU cores-of the tasks derived from structured data parallel patterns/algorithmic skeletons. The model takes into account both hardware related and application dependent parameters. It computes the percentage of tasks to be executed on CPU and GPU cores such that both kinds of cores are exploited and performance figures are optimized. The autonomic module, implemented in FastFlow, executes a generic map (reduce) data parallel pattern scheduling part of the tasks to the GPU and part to CPU cores so as to achieve optimal execution time. Experimental results on state-of-the-art CPU/GPU architectures are shown that assess both performance model properties and autonomic module effectiveness. © 2013 IEEE.

Patterns of Presentation for Attempted Suicide: Analysis of a Cohort of Individuals Who Subsequently Died by Suicide

All suicides and related prior attempts occurring in Northern Ireland over two years were analyzed, focusing on number and timing of attempts, method, and mental health diagnoses. Cases were derived from coroner's records, with 90% subsequently linked to associated general practice records. Of those included, 45% recorded at least one prior attempt (with 59% switching from less to more lethal methods between attempt and suicide). Compared with those recording one attempt, those with 2+ attempts were more likely to have used less lethal methods at the suicide (OR = 2.77: 95% CI = 1.06, 7.23); and those using less lethal methods at the attempts were more likely to persist with these into the suicide (OR = 3.21: 0.79, 13.07). Finally, those with preexisting mental problems were more likely to use less lethal methods in the suicide: severe mental illness (OR = 7.88: 1.58, 39.43); common mental problems (OR = 3.68: 0.83, 16.30); and alcohol/drugs related (OR = 2.02: 0.41, 9.95). This analysis uses readily available data to highlight the persisting use of less lethal methods by visible and vulnerable attempters who eventually complete their suicide. Further analysis of such conditions could allow more effective prevention strategies to be developed.

Patterns and processes of recent migration to Northern Ireland

This paper describes patterns and processes of recent migration in Northern Ireland. A conceptual approach is provided for spatial understandings of migration in new destinations, and the role of context is explored with regard to migration to a divided society. Recent migration to Northern Ireland is characterised and the geography of migrant residences evidenced in the 2011 Census is presented. Key patterns include the rural nature of migration in Northern Ireland, variation among migrant groups, and the spatial concentration of migrant communities. This exploration of spatial patterns is expanded on through a consideration of the processes of migration and diversification according to the themes of Finding Housing and Neighbourhood Interactions. In conclusion we explore the implications of the data presented, reflecting on spatial problems and spatial solutions in diversifying Northern Ireland.

Disturbance, neutral theory and patterns of beta diversity in soil communities

Beta diversity describes how local communities within an area or region differ in species composition/abundance. There have been attempts to use changes in beta diversity as a biotic indicator of disturbance, but lack of theory and methodological caveats have hampered progress. We here propose that the neutral theory of biodiversity plus the definition of beta diversity as the total variance of a community matrix provide a suitable, novel, starting point for ecological applications. Observed levels of beta diversity (BD) can be compared to neutral predictions with three possible outcomes: Observed BD equals neutral prediction or is larger (divergence) or smaller (convergence) than the neutral prediction. Disturbance might lead to either divergence or convergence, depending on type and strength. We here apply these ideas to datasets collected on oribatid mites (a key, very diverse soil taxon) under several regimes of disturbances. When disturbance is expected to increase the heterogeneity of soil spatial properties or the sampling strategy encompassed a range of diverging environmental conditions, we observed diverging assemblages. On the contrary, we observed patterns consistent with neutrality when disturbance could determine homogenization of soil properties in space or the sampling strategy encompassed fairly homogeneous areas. With our method, spatial and temporal changes in beta diversity can be directly and easily monitored to detect significant changes in community dynamics, although the method itself cannot inform on underlying mechanisms. However, human-driven disturbances and the spatial scales at which they operate are usually known. In this case, our approach allows the formulation of testable predictions in terms of expected changes in beta diversity, thereby offering a promising monitoring tool.

Constraining Directional Modulation Transmitter Radiation Patterns

An iterative pattern synthesis approach for directional modulation (DM) transmitters is presented in this study. Unlike all previous work, this study offers the first discussion on constraining DM transmitter far-field radiation patterns so that energy is primarily concentrated in the spatial direction where low bit error rate is to be achieved, while interference projected along other directions is reduced.

High-impedance metasurfaces with interwoven conductor patterns

High impedance metasurfaces (HIMSs) formed by interwoven conductor arrays are proposed. Bandwidth comparable with that of the basic square patches is achieved at an order of magnitude smaller unit cells. The presented structures are apt for small mobile terminals and low frequency applications.

A mixed methods study of the work patterns of full-time nurse practitioners in nursing homes

Aims and objectives: The aim of this study was to explore the integration of the nurse practitioner role in Canadian nursing homes to enable its full potential to be realised for resident and family care. The objective was to determine nurse practitioners' patterns of work activities. 

Background: Nurse practitioners were introduced in Canadian nursing homes a decade ago on a pilot basis. In recent years, government and nursing home sector interest in the role has grown along with the need for data to inform planning efforts. 

Design: The study used a sequential mixed methods design using a national survey followed by case studies. 

Methods: A national survey of nurse practitioners included demographic items and the EverCare Nurse Practitioner Role and Activity Scale. Following the survey, case studies were conducted in four nursing homes. Data were collected using individual and focus group interviews, document reviews and field notes. 

Results: Twenty-three of a target population of 26 nurse practitioners responded to the survey, two-thirds of whom provided services in nursing homes with one site and the remainder in nursing homes with as many as four sites. On average, nurse practitioners performed activities in communicator, clinician, care manager/coordinator and coach/educator subscales at least three to four times per week and activities in the collaborator subscale once a week. Of the 43 activities, nurse practitioners performed daily, most were in the clinician and communicator subscales. Case study interviews involved 150 participants. Findings complemented those of the survey and identified additional leadership activities. 

Conclusion: Nurse practitioners undertake a range of primary health care and advanced practice activities which they adapt to meet the unique needs of nursing homes. Relevance to clinical practice: Knowledge of work patterns enables nursing homes to implement the full range of nurse practitioner roles and activities to enhance resident and family care.