112 research outputs found

    Three-Dimensional Phylogeny Explorer: Distinguishing paralogs, lateral transfer, and violation of "molecular clock" assumption with 3D visualization

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    <p>Abstract</p> <p>Background</p> <p>Construction and interpretation of phylogenetic trees has been a major research topic for understanding the evolution of genes. Increases in sequence data and complexity are creating a need for more powerful and insightful tree visualization tools.</p> <p>Results</p> <p>We have developed 3D Phylogeny Explorer (3DPE), a novel phylogeny tree viewer that maps trees onto three spatial axes (species on the X-axis; paralogs on Z; evolutionary distance on Y), enabling one to distinguish at a glance evolutionary features such as speciation; gene duplication and paralog evolution; lateral gene transfer; and violation of the "molecular clock" assumption. Users can input any tree on the online 3DPE, then rotate, scroll, rescale, and explore it interactively as "live" 3D views. All objects in 3DPE are clickable to display subtrees, connectivity path highlighting, sequence alignments, and gene summary views, and etc. To illustrate the value of this visualization approach for microbial genomes, we also generated 3D phylogeny analyses for all clusters from the public COG database. We constructed tree views using well-established methods and graph algorithms. We used Scientific Python to generate VRML2 3D views viewable in any web browser.</p> <p>Conclusion</p> <p>3DPE provides a novel phylogenetic tree projection method into 3D space and its web-based implementation with live 3D features for reconstruction of phylogenetic trees of COG database.</p

    Social participation for older people with aphasia: The impact of communication disability on friendships

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    Purpose: The language changes experienced by a person with aphasia following a stroke often have sudden and long-lasting negative impact on friendships. Friendship relationships are core to social engagement, quality of life, and emotional well-being. The aims of this study were to describe everyday communication with friends for older people with and without aphasia and to examine the nature of actual friendship conversations involving a person with aphasia. Method: This naturalistic inquiry drew data from two phases of research: a participant observation study of 30 older Australians, 15 of whom had aphasia following a stroke, and a collective case study using stimulated recall to examine friendship conversations involving an older person with aphasia. Results: People with aphasia communicated with fewer friends and had smaller social networks. "Friendship" was a core domain of communication for older people and participation in leisure and educational activities was focal in everyday communication with friends. Case study data of conversations between three older people with aphasia and their friends illuminated features of "time," the role of humour, and friends having shared interests. Conclusion: Aphasia has been found to impact on friendships. A need exists for research and intervention programs to address communication with friends for older people with aphasia

    A mathematical and computational review of Hartree-Fock SCF methods in Quantum Chemistry

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    We present here a review of the fundamental topics of Hartree-Fock theory in Quantum Chemistry. From the molecular Hamiltonian, using and discussing the Born-Oppenheimer approximation, we arrive to the Hartree and Hartree-Fock equations for the electronic problem. Special emphasis is placed in the most relevant mathematical aspects of the theoretical derivation of the final equations, as well as in the results regarding the existence and uniqueness of their solutions. All Hartree-Fock versions with different spin restrictions are systematically extracted from the general case, thus providing a unifying framework. Then, the discretization of the one-electron orbitals space is reviewed and the Roothaan-Hall formalism introduced. This leads to a exposition of the basic underlying concepts related to the construction and selection of Gaussian basis sets, focusing in algorithmic efficiency issues. Finally, we close the review with a section in which the most relevant modern developments (specially those related to the design of linear-scaling methods) are commented and linked to the issues discussed. The whole work is intentionally introductory and rather self-contained, so that it may be useful for non experts that aim to use quantum chemical methods in interdisciplinary applications. Moreover, much material that is found scattered in the literature has been put together here to facilitate comprehension and to serve as a handy reference.Comment: 64 pages, 3 figures, tMPH2e.cls style file, doublesp, mathbbol and subeqn package

    Evaluation of the function and quality of life of patients submitted to girdlestone's resection arthroplasty

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    OBJECTIVES: To evaluate function and quality of life of patients submitted to Girdlestone's arthroplasty, and to compare outcomes between unilateral Girdlestone's group with the group with contralateral total hip prosthesis. METHODS: Cross-sectional study where 9 patients were evaluated with unilateral Girdlestone's and 3 with Girdlestone's in one hip and contralateral total hip prosthesis. The evaluation consisted in filling in a generic questionnaire on quality of life SF-36 and a specific questionnaire for hip function Harris Hip Score (HHS). The comparison between groups was made by using the Student's t-test and the Fisher's test. RESULTS: The patients of the unilateral Girdlestone's group presented a higher number of SF-36 domains classified as high, although 77.8% of these showed poor results on the HHS. All patients had a leg-length discrepancy and positive Trendelenburg's test, which led to limping gait in 11 of 12 patients evaluated. Of these, only 6 underwent physiotherapy after surgery. CONCLUSION: Girdlestone's postoperative quality of life and function in a Brazilian population still requires further studies, because these outcomes are indicative of study variables' behavior and cannot be regarded as definite.OBJETIVOS: Avaliar a função e a qualidade de vida dos pacientes pós-artroplastia de Girdlestone e comparar os resultados entre os grupos Girdlestone unilateral e o grupo com prótese total de quadril contralateral. MÉTODOS: estudo transversal no qual foram avaliados 9 pacientes com Girdlestone unilateral e 3 com Girdlestone em um quadril e prótese total no quadril contralateral. A avaliação constitui-se em aplicar o questionário genérico de qualidade de vida SF-36 e um questionário funcional específico para o quadril, Harris Hip Score (HHS). A comparação dos grupos foi realizada usando-se o teste t- Student e o teste de Fisher. RESULTADOS: Os pacientes do grupo Girdlestone unilateral apresentaram maior quantidade de domínios do SF-36 classificados como elevados, embora 77,8% destes tenham obtido resultados ruins no HHS. Todos os pacientes apresentaram o teste de Trendelenburg positivo e discrepância de membros, o que levou à marcha claudicante em 11 dos 12 pacientes avaliados. Destes, apenas 6 submeteram-se a fisioterapia pós-operatória. CONCLUSÃO: A qualidade de vida e a função pós-operatória de Girdlestone, na população brasileira, ainda necessita ser mais pesquisada, pois estes resultados são indicações do comportamento das variáveis de estudo e não podem ser consideradas encerradas.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Ortopedia e TraumatologiaUNIFESP-EPM DOTUNIFESP, EPM, Depto. de Ortopedia e TraumatologiaUNIFESP, EPM DOTSciEL

    Apoptotic cell-based therapies against transplant rejection: role of recipient’s dendritic cells

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    One of the ultimate goals in transplantation is to develop novel therapeutic methods for induction of donor-specific tolerance to reduce the side effects caused by the generalized immunosuppression associated to the currently used pharmacologic regimens. Interaction or phagocytosis of cells in early apoptosis exerts potent anti-inflammatory and immunosuppressive effects on antigen (Ag)-presenting cells (APC) like dendritic cells (DC) and macrophages. This observation led to the idea that apoptotic cell-based therapies could be employed to deliver donor-Ag in combination with regulatory signals to recipient’s APC as therapeutic approach to restrain the anti-donor response. This review describes the multiple mechanisms by which apoptotic cells down-modulate the immuno-stimulatory and pro-inflammatory functions of DC and macrophages, and the role of the interaction between apoptotic cells and APC in self-tolerance and in apoptotic cell-based therapies to prevent/treat allograft rejection and graft-versus-host disease in murine experimental systems and in humans. It also explores the role that in vivo-generated apoptotic cells could have in the beneficial effects of extracorporeal photopheresis, donor-specific transfusion, and tolerogenic DC-based therapies in transplantation

    An Individual-Oriented Model on the Emergence of Support in Fights, Its Reciprocation and Exchange

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    Complex social behaviour of primates has usually been attributed to the operation of complex cognition. Recently, models have shown that constraints imposed by the socio-spatial structuring of individuals in a group may result in an unexpectedly high number of patterns of complex social behaviour, resembling the dominance styles of egalitarian and despotic species of macaques and the differences between them. This includes affiliative patterns, such as reciprocation of grooming, grooming up the hierarchy, and reconciliation. In the present study, we show that the distribution of support in fights, which is the social behaviour that is potentially most sophisticated in terms of cognitive processes, may emerge in the same way. The model represents the spatial grouping of individuals and their social behaviour, such as their avoidance of risks during attacks, the self-reinforcing effects of winning and losing their fights, their tendency to join in fights of others that are close by (social facilitation), their tendency to groom when they are anxious, the reduction of their anxiety by grooming, and the increase of anxiety when involved in aggression. Further, we represent the difference in intensity of aggression apparent in egalitarian and despotic macaques. The model reproduces many aspects of support in fights, such as its different types, namely, conservative, bridging and revolutionary, patterns of choice of coalition partners attributed to triadic awareness, those of reciprocation of support and ‘spiteful acts’ and of exchange between support and grooming. This work is important because it suggests that behaviour that seems to result from sophisticated cognition may be a side-effect of spatial structure and dominance interactions and it shows that partial correlations fail to completely omit these effects of spatial structure. Further, the model is falsifiable, since it results in many patterns that can easily be tested in real primates by means of existing data

    New Strategies in Modeling Electronic Structures and Properties with Applications to Actinides

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    This chapter discusses contemporary quantum chemical methods and provides general insights into modern electronic structure theory with a focus on heavy-element-containing compounds. We first give a short overview of relativistic Hamiltonians that are frequently applied to account for relativistic effects. Then, we scrutinize various quantum chemistry methods that approximate the NN-electron wave function. In this respect, we will review the most popular single- and multi-reference approaches that have been developed to model the multi-reference nature of heavy element compounds and their ground- and excited-state electronic structures. Specifically, we introduce various flavors of post-Hartree--Fock methods and optimization schemes like the complete active space self-consistent field method, the configuration interaction approach, the Fock-space coupled cluster model, the pair-coupled cluster doubles ansatz, also known as the antisymmetric product of 1 reference orbital geminal, and the density matrix renormalization group algorithm. Furthermore, we will illustrate how concepts of quantum information theory provide us with a qualitative understanding of complex electronic structures using the picture of interacting orbitals. While modern quantum chemistry facilitates a quantitative description of atoms and molecules as well as their properties, concepts of quantum information theory offer new strategies for a qualitative interpretation that can shed new light onto the chemistry of complex molecular compounds.Comment: 43 pages, 3 figures, Version of Recor
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