295 research outputs found
Fabrication of multiphasic and regio-specifically functionalized PRINT ® particles of controlled size and shape
Using Particle Replication In Nonwetting Templates (PRINT®) technology, multiphasic and regio-specifically functionalized shape-controlled particles have been fabricated that include end-labeled particles via post-functionalization; biphasic Janus particles that integrate two compositionally different chemistries into a single particle; and more complex multiphasic shape-specific particles. Controlling the anisotropic distribution of matter within a particle creates an extra parameter in the colloidal particle design, providing opportunities to generate advanced particles with versatile and tunable compositions, properties, and thus functionalities. Owing to their robust characteristics, these multiphasic and regio-specifically functionalized PRINT particles should be promising platforms for applications in life science and materials science
Ordering heuristics for parallel graph coloring
This paper introduces the largest-log-degree-first (LLF) and smallest-log-degree-last (SLL) ordering heuristics for paral-lel greedy graph-coloring algorithms, which are inspired by the largest-degree-first (LF) and smallest-degree-last (SL) serial heuristics, respectively. We show that although LF and SL, in prac-tice, generate colorings with relatively small numbers of colors, they are vulnerable to adversarial inputs for which any paralleliza-tion yields a poor parallel speedup. In contrast, LLF and SLL allow for provably good speedups on arbitrary inputs while, in practice, producing colorings of competitive quality to their serial analogs. We applied LLF and SLL to the parallel greedy coloring algo-rithm introduced by Jones and Plassmann, referred to here as JP. Jones and Plassman analyze the variant of JP that processes the ver-tices of a graph in a random order, and show that on an O(1)-degree graph G = (V,E), this JP-R variant has an expected parallel run-ning time of O(lgV / lg lgV) in a PRAM model. We improve this bound to show, using work-span analysis, that JP-R, augmented to handle arbitrary-degree graphs, colors a graph G = (V,E) with degree ∆ using Θ(V +E) work and O(lgV + lg ∆ ·min{√E,∆+ lg ∆ lgV / lg lgV}) expected span. We prove that JP-LLF and JP-SLL — JP using the LLF and SLL heuristics, respectively — execute with the same asymptotic work as JP-R and only logarith-mically more span while producing higher-quality colorings than JP-R in practice. We engineered an efficient implementation of JP for modern shared-memory multicore computers and evaluated its performance on a machine with 12 Intel Core-i7 (Nehalem) processor cores. Our implementation of JP-LLF achieves a geometric-mean speedup of 7.83 on eight real-world graphs and a geometric-mean speedup of 8.08 on ten synthetic graphs, while our implementation using SLL achieves a geometric-mean speedup of 5.36 on these real-world graphs and a geometric-mean speedup of 7.02 on these synthetic graphs. Furthermore, on one processor, JP-LLF is slightly faster than a well-engineered serial greedy algorithm using LF, and like-wise, JP-SLL is slightly faster than the greedy algorithm using SL
Distribution of \u3cem\u3eCotesia rubecula\u3c/em\u3e (Hymenoptera: Braconidae) and Its Displacement of \u3cem\u3eCotesia glomerata\u3c/em\u3e in Eastern North America
A survey was conducted from May to Oct of 2011 of the parasitoid community of the imported cabbageworm, Pieris rapae (Lepidoptera: Pieridae), in cole crops in part of the eastern United States and southeastern Canada. The findings of our survey indicate that Cotesia rubecula (Hymenoptera: Braconidae) now occurs as far west as North Dakota and has become the dominant parasitoid of P. rapae in the northeastern and north central United States and adjacent parts of southeastern Canada, where it has displaced the previously common parasitoid Cotesia glomerata (Hymenoptera: Braconidae). Cotesia glomerata remains the dominant parasitoid in the mid-Atlantic states, from Virginia to North Carolina and westward to southern Illinois, below latitude N 38° 48′. This pattern suggests that the released populations of C. rubecula presently have a lower latitudinal limit south of which they are not adapted
Migration experiences, employment status and psychological distress among Somali immigrants: a mixed-method international study
Background:
The discourse about mental health problems among migrants and refugees tends to focus on adverse pre-migration experiences; there is less investigation of the environmental conditions in which refugee migrants live, and the contrasts between these situations in different countries. This cross-national study of two samples of Somali refugees living in London (UK) and Minneapolis, Minnesota, (USA) helps to fill a gap in the literature, and is unusual in being able to compare information collected in the same way in two cities in different countries.
Methods:
There were two parts to the study, focus groups to gather in-depth qualitative data and a survey of health status and quantifiable demographic and material factors. Three of the focus groups involved nineteen Somali professionals and five groups included twenty-eight lay Somalis who were living in London and Minneapolis. The quantitative survey was done with 189 Somali respondents, also living in London and Minneapolis. We used the MINI International Neuropsychiatric Interview (MINI) to assess ICD-10 and
Results:
The overall qualitative and quantitative results suggested that challenges to masculinity, thwarted aspirations, devalued refugee identity, unemployment, legal uncertainties and longer duration of stay in the host country account for poor psychological well-being and psychiatric disorders among this group.
Conclusion:
The use of a mixed-methods approach in this international study was essential since the quantitative and qualitative data provide different layers and depth of meaning and complement each other to provide a fuller picture of complex and multi-faceted life situations of refugees and asylum seekers. The comparison between the UK and US suggests that greater flexibility of access to labour markets for this refugee group might help to promote opportunities for better integration and mental well-being
On the Relative Expressive Power of Asynchronous Communication Primitives
In this paper, we study eight asynchronous communication primitives, arising from the combination of three features: arity (monadic vs polyadic data), communication medium (message passing vs shared dataspaces) and pattern-matching. Each primitive has been already used in at least one language appeared in literature; however, to uniformly reason on such primitives, we plugged them in a common framework inspired by the asynchronous-calculus. By means of possibility/impossibility of ‘reasonable ’ encodings, we compare every pair of primitives to obtain a hierarchy of languages based on their relative expressive power.
Successful recruitment to trials : findings from the SCIMITAR+ Trial
BACKGROUND: Randomised controlled trials (RCT) can struggle to recruit to target on time. This is especially the case with hard to reach populations such as those with severe mental ill health. The SCIMITAR+ trial, a trial of a bespoke smoking cessation intervention for people with severe mental ill health achieved their recruitment ahead of time and target. This article reports strategies that helped us to achieve this with the aim of aiding others recruiting from similar populations. METHODS: SCIMITAR+ is a multi-centre pragmatic two-arm parallel-group RCT, which aimed to recruit 400 participants with severe mental ill health who smoke and would like to cut down or quit. The study recruited primarily in secondary care through community mental health teams and psychiatrists with a smaller number of participants recruited through primary care. Recruitment opened in October 2015 and closed in December 2016, by which point 526 participants had been recruited. We gathered information from recruiting sites on strategies which led to the successful recruitment in SCIMITAR+ and in this article present our approach to trial management along with the strategies employed by the recruiting sites. RESULTS: Alongside having a dedicated trial manager and trial management team, we identified three main themes that led to successful recruitment. These were: clinicians with a positive attitude to research; researchers and clinicians working together; and the use of NHS targets. The overriding theme was the importance of relationships between both the researchers and the recruiting clinicians and the recruiting clinicians and the participants. CONCLUSIONS: This study makes a significant contribution to the limited evidence base of real-world cases of successful recruitment to RCTs and offers practical guidance to those planning and conducting trials. Building positive relationships between clinicians, researchers and participants is crucial to successful recruitment
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