326 research outputs found

    On the frequency of permutations containing a long cycle

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    A general explicit upper bound is obtained for the proportion P(n,m)P(n,m) of elements of order dividing mm, where n1mcnn-1 \le m \le cn for some constant cc, in the finite symmetric group SnS_n. This is used to find lower bounds for the conditional probabilities that an element of SnS_n or AnA_n contains an rr-cycle, given that it satisfies an equation of the form xrs=1x^{rs}=1 where s3s\leq3. For example, the conditional probability that an element xx is an nn-cycle, given that xn=1x^n=1, is always greater than 2/7, and is greater than 1/2 if nn does not divide 24. Our results improve estimates of these conditional probabilities in earlier work of the authors with Beals, Leedham-Green and Seress, and have applications for analysing black-box recognition algorithms for the finite symmetric and alternating groups

    Including Women? (Dis)junctures Between Voice,

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    Abstract Integrated development plans (IDPs) are municipal strategic plans designed to bring about developmental local government. They have been criticised for providing insufficient space for democratic participation. This paper explores the extent to which a marginalised group—women—has been incorporated into the IDP process, in response to three questions. First, how have IDP participatory processes incorporated women’s voice, and are the new participatory spaces realising their transformative potential? Secondly, how have women’s interests and a gender perspective been mainstreamed in the IDP, and has it promoted transformation? And finally, at the interface between officials and women themselves, how are IDP projects implemented and does agency promote or impede the goals of gender equality? A study of three KwaZulu-Natal municipalities reveals some achievements, but unequal gender relations have not been transformed. These case studies demonstrate some of the complexities and difficulties in the practice of democratic governance

    The integration of rapid qualitative research in clinical trials: reflections from the ward-based goal-directed fluid therapy (GDFT) in acute pancreatitis feasibility trial

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    Background: There has been an increase in the integration of qualitative studies in randomised controlled trials. The purpose of this article is to reflect on our experience of carrying out a rapid qualitative study during a feasibility trial of goal-directed fluid therapy (GDFT) in patients with acute pancreatitis, including our sharing of emerging findings and the use of these findings by the trial team. / Methods: The study was designed as a rapid feedback evaluation and combined interviews with staff and patients who took part in the trial. / Findings: The rapid qualitative study pointed to common problems in trial recruitment among multiple sites, where lack of engagement of clinical teams across sites might impact negatively on patient recruitment. The article describes how the use of rapid feedback loops can be used as the trial is ongoing to inform changes in implementation. It also covers the potential challenges of working rapidly and collaborative with the trial team. / Conclusions: Rapid feedback evaluations can be used to generate findings across all stages of trial design and delivery. Additional research is required to explore the implementation of this research design in other settings and trial designs

    Time evolution of non-Hermitian Hamiltonian systems

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    We provide time-evolution operators, gauge transformations and a perturbative treatment for non-Hermitian Hamiltonian systems, which are explicitly time-dependent. We determine various new equivalence pairs for Hermitian and non-Hermitian Hamiltonians, which are therefore pseudo-Hermitian and in addition in some cases also invariant under PT-symmetry. In particular, for the harmonic oscillator perturbed by a cubic non-Hermitian term, we evaluate explicitly various transition amplitudes, for the situation when these systems are exposed to a monochromatic linearly polarized electric field.Comment: 25 pages Latex, 1 eps figure, references adde

    Carbon fragmentation measurements and validation of the GEANT4 nuclear reaction models for hadrontherapy

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    Nuclear fragmentation measurements are necessary when using heavy-ion beams in hadrontherapy to predict the effects of the ion nuclear interactions within the human body. Moreover, they are also fundamental to validate and improve the Monte Carlo codes for their use in planning tumor treatments. Nowadays, a very limited set of carbon fragmentation cross sections are being measured, and in particular, to our knowledge, no double-differential fragmentation cross sections at intermediate energies are available in the literature. In this work, we have measured the double-differential cross sections and the angular distributions of the secondary fragments produced in the C-12 fragmentation at 62 A MeV on a thin carbon target. The experimental data have been used to benchmark the prediction capability of the GEANT4 Monte Carlo code at intermediate energies, where it was never tested before. In particular, we have compared the experimental data with the predictions of two GEANT4 nuclear reaction models: the Binary Light Ions Cascade and the Quantum Molecular Dynamic. From the comparison, it has been observed that the Binary Light Ions Cascade approximates the angular distributions of the fragment production cross sections better than the Quantum Molecular Dynamic model. However, the discrepancies observed between the experimental data and the Monte Carlo simulations lead to the conclusion that the prediction capability of both models needs to be improved at intermediate energies

    A Molecular Phylogeny of the Chalcidoidea (Hymenoptera)

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    Chalcidoidea (Hymenoptera) are extremely diverse with more than 23,000 species described and over 500,000 species estimated to exist. This is the first comprehensive phylogenetic analysis of the superfamily based on a molecular analysis of 18S and 28S ribosomal gene regions for 19 families, 72 subfamilies, 343 genera and 649 species. The 56 outgroups are comprised of Ceraphronoidea and most proctotrupomorph families, including Mymarommatidae. Data alignment and the impact of ambiguous regions are explored using a secondary structure analysis and automated (MAFFT) alignments of the core and pairing regions and regions of ambiguous alignment. Both likelihood and parsimony approaches are used to analyze the data. Overall there is no impact of alignment method, and few but substantial differences between likelihood and parsimony approaches. Monophyly of Chalcidoidea and a sister group relationship between Mymaridae and the remaining Chalcidoidea is strongly supported in all analyses. Either Mymarommatoidea or Diaprioidea are the sister group of Chalcidoidea depending on the analysis. Likelihood analyses place Rotoitidae as the sister group of the remaining Chalcidoidea after Mymaridae, whereas parsimony nests them within Chalcidoidea. Some traditional family groups are supported as monophyletic (Agaonidae, Eucharitidae, Encyrtidae, Eulophidae, Leucospidae, Mymaridae, Ormyridae, Signiphoridae, Tanaostigmatidae and Trichogrammatidae). Several other families are paraphyletic (Perilampidae) or polyphyletic (Aphelinidae, Chalcididae, Eupelmidae, Eurytomidae, Pteromalidae, Tetracampidae and Torymidae). Evolutionary scenarios discussed for Chalcidoidea include the evolution of phytophagy, egg parasitism, sternorrhynchan parasitism, hypermetamorphic development and heteronomy

    Skeletal Morphology of Opius dissitus and Biosteres carbonarius (Hymenoptera: Braconidae), with a Discussion of Terminology

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    The Braconidae, a family of parasitic wasps, constitute a major taxonomic challenge with an estimated diversity of 40,000 to 120,000 species worldwide, only 18,000 of which have been described to date. The skeletal morphology of braconids is still not adequately understood and the terminology is partly idiosyncratic, despite the fact that anatomical features form the basis for most taxonomic work on the group. To help address this problem, we describe the external skeletal morphology of Opius dissitus Muesebeck 1963 and Biosteres carbonarius Nees 1834, two diverse representatives of one of the least known and most diverse braconid subfamilies, the Opiinae. We review the terminology used to describe skeletal features in the Ichneumonoidea in general and the Opiinae in particular, and identify a list of recommend terms, which are linked to the online Hymenoptera Anatomy Ontology. The morphology of the studied species is illustrated with SEM-micrographs, photos and line drawings. Based on the examined species, we discuss intraspecific and interspecific morphological variation in the Opiinae and point out character complexes that merit further study

    "It was the whole picture" a mixed methods study of successful components in an integrated wellness service in North East England

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    Background A growing number of Local Authorities (LAs) have introduced integrated wellness services as part of efforts to deliver cost effective, preventive services that address the social determinants of health. This study examined which elements of an integrated wellness service in the north east of England were effective in improving health and wellbeing (HWB). Methods The study used a mixed-methods approach. In-depth semi-structured interviews (IVs) were conducted with integrated wellness service users (n = 25) and focus groups (FGs) with group based service users (n = 14) and non-service users (n = 23) to gather the views of stakeholders. Findings are presented here alongside analysis of routine monitoring data. The different data were compared to examine what each data source revealed about the effectiveness of the service. Results Findings suggest that integrated wellness services work by addressing the social determinants of health and respond to multiple complex health and social concerns rather than single issues. The paper identifies examples of ‘active ingredients’ at the heart of the programme, such as sustained relationships, peer support and confidence building, as well as the activities through which changes take place, such as sports and leisure opportunities which in turn encourage social interaction. Wider wellbeing outcomes, including reduced social isolation and increased self-efficacy are also reported. Practical and motivational support helped build community capacity by encouraging community groups to access funding, helped navigate bureaucratic systems, and promoted understanding of marginalised communities. Fully integrated wellness services could support progression opportunities through volunteering and mentoring. Conclusions An integrated wellness service that offers a holistic approach was valued by service users and allowed them to address complex issues simultaneously. Few of the reported health gains were captured in routine data. Quantitative and qualitative data each offered a partial view of how effectively services were working
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