20 research outputs found

    Genome Sequence of the Pea Aphid Acyrthosiphon pisum

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    Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems

    Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

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    37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe

    Intraosseous lipoma: radiological findings Lipoma intra-ósseo: achados radiológicos

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    OBJECTIVE: Intraosseous lipomas may be less rare lesions than previously suggested in the literature. They have frequently been misdiagnosed as other benign bone lesions. A combination of computed tomography, magnetic resonance imaging and radiography is essential for decreasing misdiagnosis rates. MATERIALS AND METHODS: This retrospective study presents ten cases of intraosseous lipoma. The patients' ages ranged from 25 to 80 years, and six of them were female. Six patients presented with bone pain, whereas four patients were asymptomatic with incidentally discovered lesions. The involved bones were: femur (four patients), tibia (two patients), calcaneus (one patient), sacrum (one patient), iliac bone (one patient), navicular bone (one patient). All of the patients were assessed by means of conventional radiography, computed tomography and magnetic resonance imaging of the affected region. RESULTS: In all of the cases, plain films revealed well-defined lytic lesions. Both computed tomography and magnetic resonance imaging were quite useful in demonstrating fat within the femur. The histologic pattern of all tumors was that of mature adipose tissue. CONCLUSION: Intraosseous lipoma is a well-defined entity that may develop with varying presentations. Plain radiographs alone cannot establish the diagnosis of this lesion. However, both computed tomography and magnetic resonance imaging are quite useful methods in these cases.<br>OBJETIVO: Lipomas intra-ósseos podem ser lesões menos raras do que anteriormente sugerido na literatura. Freqüentemente têm sido erroneamente diagnosticados como outras lesões ósseas benignas. A combinação de tomografia computadorizada, ressonância magnética e radiografia é essencial para reduzir as taxas de erro diagnóstico. MATERIAIS E MÉTODOS: Este estudo retrospectivo apresenta dez casos de lipoma intra-ósseo. As idades dos pacientes variavam entre 25 e 80 anos, e seis deles eram do sexo feminino. Seis pacientes apresentavam dor óssea, enquanto quatro eram assintomáticos com lesões descobertas casualmente. Os ossos afetados foram: fêmur (quatro pacientes), tíbia (dois pacientes), calcâneo (um paciente), sacro (um paciente), osso ilíaco (um paciente), osso navicular (um paciente). Todos os pacientes foram avaliados por meio de radiografia convencional, tomografia computadorizada e ressonância magnética das regiões afetadas. RESULTADOS: Em todos os casos, as radiografias revelaram lesões líticas bem delimitadas. Tanto a tomografia computadorizada como a ressonância magnética foram bastante úteis para demonstrar gordura dentro do tumor. O padrão histológico de todos os tumores caracterizou-se por tecido adiposo maduro. CONCLUSÃO: Lipoma intra-ósseo é uma entidade bem definida que pode se desenvolver com variadas apresentações. Radiografias convencionais, isoladamente, não podem diagnosticar essas lesões. Entretanto, a tomografia computadorizada e a ressonância magnética são métodos bastante úteis nesses casos
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