106 research outputs found

    Simultaneous-FETI and Block-FETI: robust domain decomposition with multiple search directions.

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    International audienceDomain Decomposition methods often exhibit very poor performance when applied to engineering problems with large heterogeneities. In particular for heterogeneities along domain interfaces the iterative techniques to solve the interface problem are lacking an efficient preconditioner. Recently a robust approach, named FETI-Geneo, was proposed where troublesome modes are precomputed and deflated from the interface problem. The cost of the FETI-Geneo is however high. We propose in this paper techniques that share similar ideas with FETI-Geneo but where no pre-processing is needed and that can be easily and efficiently implemented as an alternative to standard Domain Decomposition methods. In the block iterative approaches presented in this paper, the search space at every iteration on the interface problem contains as many directions as there are domains in the decomposition. Those search directions originate either from the domain-wise preconditioner (in the Simultaneous FETI method) or from the block structure of the right-hand side of the interface problem (Block FETI). We show on 2D structural examples that both methods are robust and provide good convergence in the presence of high heterogeneities, even when the interface is jagged or when the domains have a bad aspect ratio. The Simultaneous FETI was also efficiently implemented in an optimized parallel code and exhibited excellent performance compared to the regular FETI method

    Solving generalized eigenvalue problems on the interfaces to build a robust two level FETI method

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    FETI is a very popular method which has proved to be extremely efficient on many large scale industrial problems. One drawback is that it performs best when the decomposition of the global problem is closely related to the parameters in equations. This is somewhat confirmed by the fact that the theoretical analysis goes through only if some assumptions on the coefficients are satisfied. We propose here to build a coarse space for which the convergence rate of the two level method is guaranteed regardless of any additional assumptions. We do this by identifying the problematic modes using generalized eigenvalue problems

    Factors influencing the prescribing behaviour of independent prescriber optometrists:a qualitative study using the Theoretical Domains Framework

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    Purpose Whilst the number of independent prescriber (IP) optometrists in the United Kingdom is increasing, there is limited evidence describing the experiences of these individuals. The Theoretical Domains Framework (TDF) provides an evidence‐based approach to understand determinants of behaviour. This conceptual framework can enable mapping to the COM‐B behaviour change model and the wider Behaviour Change Wheel to develop interventions to optimise behaviour‐change and healthcare processes more systematically. The study aimed to use the TDF to identify the factors that influence independent prescribing behaviour, and to map these findings to the COM‐B system to elucidate the relevant intervention functions, in order to identify the support required by optometrist prescribers. Methods Using a qualitative design, semi‐structured interviews based on the TDF were undertaken with independent prescriber optometrists. Thematic analysis was used to identify themes inductively, which were then deductively mapped to the TDF and linked to the COM‐B. Results Sixteen participants (9 male, 7 female; median age 45 years, range 28–65 years), based in community (n = 10) and hospital (n = 6) settings, were interviewed. Eleven of the TDF domains were found to influence prescribing behaviour. Findings highlighted the need for good communication with patients (TDF domain: Skills, COM‐B: Capability); confidence (TDF domain: Beliefs about capabilities, COM‐B: Motivation); good networks and relationships with other healthcare professionals, e.g., general practitioners (TDF domain: Social influences, COM‐B: Opportunity; TDF domain: Social/professional role and identity, COM‐B: Motivation); the need for appropriate structure for remuneration (TDF domain: Reinforcement, COM‐B: Motivation; TDF domain: Social/professional role and identity, COM‐B: Motivation) and the provision of professional guidelines (TDF domain: Knowledge, COM‐B: Capability; TDF domain: Environmental context and resources, COM‐B Opportunity). Conclusions Having identified theory‐derived influencers on prescribing decisions by optometrists, the findings can be used to develop a structured intervention, such as a support package to help optimise prescribing by optometrists, with the ultimate goal of eye care quality improvement

    Staging the clinical status from blood of cancer patients by chip-based cell enumeration following targeted removal of normal cells

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    Even though an agreed phenotypic definition of circulating tumor cells (CTCs) remains elusive in the literature, many current detection technologies isolate candidate cells based on molecular recognition of cellular epitopes that may not accurately predict CTC load. Rather than using such an epitope specific “positive-capture” strategy, we present a chip-based, centrifugal microfluidic platform integrating “negative-capture” magnetophoretic removal of normal white blood cells (WBCs) from a sample and subsequent, array-based enumeration of individualized, (untagged) abnormal cells. We compared the numerical recovery of cells on the array with the status of the donor patient, showing that the chip can has the potential to indicate the oncogenic severity of the blood donor

    Solving generalized eigenvalue problems on the interfaces to build a robust two-level FETI method

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    International audienceFETI is a very popular method, which has proved to be extremely efficient on many large-scale industrial problems. One drawback is that it performs best when the decomposition of the global problem is closely related to the parameters in equations. This is somewhat confirmed by the fact that the theoretical analysis goes through only if some assumptions on the coefficients are satisfied. We propose here to build a coarse space for which the convergence rate of the two-level method is guaranteed regardless of any additional assumptions. We do this by identifying the problematic modes using generalized eigenvalue problems

    Evaluating the national multisite implementation of dialectical behaviour therapy in a community setting: a mixed methods approach

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    BACKGROUND: The implementation of evidence-based interventions for borderline personality disorder in community settings is important given that individuals with this diagnosis are often extensive users of both inpatient and outpatient mental health services. Although work in this area is limited, previous studies have identified facilitators and barriers to successful DBT implementation. This study seeks to expand on previous work by evaluating a coordinated implementation of DBT in community settings at a national level. The Consolidated Framework for Implementation Research (CFIR) (Damschroder et al., Implementation Sci. 4:50, 2009) provided structural guidance for this national level coordinated implementation. METHODS: A mixed methods approach was utilised to explore the national multisite implementation of DBT from the perspective of team leaders and therapists who participated in the coordinated training and subsequent implementation of DBT. Qualitative interviews with DBT team leaders (n = 8) explored their experiences of implementing DBT in their local service and was analysed using content analysis. Quantitative surveys from DBT therapists (n = 74) examined their experience of multiple aspects of the implementation process including orienting the system, and preparations and support for implementation. Frequencies of responses were calculated. Written qualitative feedback was analysed using content analysis. RESULTS: Five themes were identified from the interview data: team formation, implementation preparation, client selection, service level challenges and team leader role. Participants identified team size and support for the team leader as key points for consideration in DBT implementation. Key challenges encountered were the lack of system support to facilitate phone coaching and a lack of allocated time to focus on DBT. Implementation facilitators included having dedicated team members and support from management. CONCLUSIONS: The barriers and facilitators identified in this study are broadly similar to those reported in previous research. Barriers and facilitators were identified across several domains of the CFIR and are consistent with a recently published DBT implementation Framework (Toms et al., Borderline Personal Disord Emot Dysregul. 6: 2, 2019). Future research should pay particular attention to the domain of characteristics of individuals involved in DBT implementation. The results highlight the importance of a mandated service plan for the coordinated implementation of an evidence-based treatment in a public health service

    Recurrent myositis triggered by infections: a case report

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    © 2008 Wong et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

    Genome sequencing of the extinct Eurasian wild aurochs, Bos primigenius, illuminates the phylogeography and evolution of cattle

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    Background Domestication of the now-extinct wild aurochs, Bos primigenius, gave rise to the two major domestic extant cattle taxa, B. taurus and B. indicus. While previous genetic studies have shed some light on the evolutionary relationships between European aurochs and modern cattle, important questions remain unanswered, including the phylogenetic status of aurochs, whether gene flow from aurochs into early domestic populations occurred, and which genomic regions were subject to selection processes during and after domestication. Here, we address these questions using whole-genome sequencing data generated from an approximately 6,750-year-old British aurochs bone and genome sequence data from 81 additional cattle plus genome-wide single nucleotide polymorphism data from a diverse panel of 1,225 modern animals. Results Phylogenomic analyses place the aurochs as a distinct outgroup to the domestic B. taurus lineage, supporting the predominant Near Eastern origin of European cattle. Conversely, traditional British and Irish breeds share more genetic variants with this aurochs specimen than other European populations, supporting localized gene flow from aurochs into the ancestors of modern British and Irish cattle, perhaps through purposeful restocking by early herders in Britain. Finally, the functions of genes showing evidence for positive selection in B. taurus are enriched for neurobiology, growth, metabolism and immunobiology, suggesting that these biological processes have been important in the domestication of cattle. Conclusions This work provides important new information regarding the origins and functional evolution of modern cattle, revealing that the interface between early European domestic populations and wild aurochs was significantly more complex than previously thought

    Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

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    Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

    Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

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    Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN
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