549 research outputs found

    Estudo de viabilidade para empresa de pré-armação com base em Lajeado: estudo dos perfis de consumo do aço

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    Por ser grande absorvedora de mão de obra desqualificada, a construção civil pode ter maior produtividade caso utilize materiais com maiores níveis de industrialização. Neste contexto citam-se os 3 diferentes tipos de fornecimento de aço para a construção civil: fornecido em barras, cortado e dobrado e o pré-armado. O fornecimento pré-armado possui o maior nível de industrialização, pois os elementos estruturais são entregues pré-prontos, necessitando apenas fazer pequenos ajustes in loco para posicionar os elementos dentro das fôrmas. O objetivo principal deste trabalho é avaliar a viabilidade da implantação de uma empresa de pré-armação de aço, com base em Lajeado/RS, sob a ótica do custo de serviço, do custo logístico e de capacidade do mercado consumidor regional. A empresa a ser viabilizada é um novo segmento para uma empresa existente, a qual já possui o fornecimento de aço em barras e cortado e dobrado. Com isso, foram obtidos dados de fornecimento de aço em barras e aço cortado e dobrado do ano de 2015 desta empresa, a qual possui atuação regional. A pré-armação através do aço cortado e dobrado gera uma economia de aproximadamente 50% no custo do serviço, se comparado ao custo de serviço de pré-armação através de barras. A empresa terá viabilidade se obter o aço cortado e dobrado como matéria prima, e poderá ter melhores resultados se apresentar maior produtividade do que a existente na bibliografia consultada, uma vez que em ambiente fabril, com profissionais qualificados e com apoio de pontes rolantes, a produtividade tende a aumentar

    Dynamics of quantum spin systems in dimer and valence-bond solid ground states stabilized by competing interactions

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    For special coupling ratios, the one-dimensional (1D) s=1/2 Heisenberg model with antiferromagnetic nearest and next-nearest neighbor interactions has a pure dimer ground state, and the 1D s=1 Heisenberg model with antiferromagnetic bilinear and biquadratic interactions has an exact valence-bond-solid ground state. The recursion method is used to calculate the T=0 spin dynamic structure factor for both models and, for the s=1/2 model, also the dimer dynamic structure factor. New results for line shapes and dynamically relevant dispersions are obtained.Comment: RevTex file, 3 ps figure

    An Application-Specific Instruction Set for Accelerating Set-Oriented Database Primitives

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    The key task of database systems is to efficiently manage large amounts of data. A high query throughput and a low query latency are essential for the success of a database system. Lately, research focused on exploiting hardware features like superscalar execution units, SIMD, or multiple cores to speed up processing. Apart from these software optimizations for given hardware, even tailor-made processing circuits running on FPGAs are built to run mostly stateless query plans with incredibly high throughput. A similar idea, which was already considered three decades ago, is to build tailor-made hardware like a database processor. Despite their superior performance, such application-specific processors were not considered to be beneficial because general-purpose processors eventually always caught up so that the high development costs did not pay off. In this paper, we show that the development of a database processor is much more feasible nowadays through the availability of customizable processors. We illustrate exemplarily how to create an instruction set extension for set-oriented database rimitives. The resulting application-specific processor provides not only a high performance but it also enables very energy-efficient processing. Our processor requires in various configurations more than 960x less energy than a high-end x86 processor while providing the same performance

    HW/SW-database-codesign for compressed bitmap index processing

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    Compressed bitmap indices are heavily used in scientific and commercial database systems because they largely improve query performance for various workloads. Early research focused on finding tailor-made index compression schemes that are amenable for modern processors. Improving performance further typically comes at the expense of a lower compression rate, which is in many applications not acceptable because of memory limitations. Alternatively, tailor-made hardware allows to achieve a performance that can only hardly be reached with software running on general-purpose CPUs. In this paper, we will show how to create a custom instruction set framework for compressed bitmap processing that is generic enough to implement most of the major compressed bitmap indices. For evaluation, we implemented WAH, PLWAH, and COMPAX operations using our framework and compared the resulting implementation to multiple state-of-the-art processors. We show that the custom-made bitmap processor achieves speedups of up to one order of magnitude by also using two orders of magnitude less energy compared to a modern energy-efficient Intel processor. Finally, we discuss how to embed our processor with database-specific instruction sets into database system environments

    Withdrawal and Re-treatment with Filgotinib in Ulcerative Colitis: Post Hoc Analyses of the Phase 2b/3 SELECTION and SELECTIONLTE Studies

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    BACKGROUND AND AIMS Maintenance treatment for ulcerative colitis may be discontinued for multiple reasons. This post hoc analysis assessed the efficacy and safety of re-treatment with filgotinib, an oral, once-daily, Janus kinase 1 preferential inhibitor, in the phase 2b/3 SELECTION trial and its long-term extension [LTE] study in ulcerative colitis. METHODS Partial Mayo Clinic Score [pMCS] response and remission were evaluated in patients who received induction with filgotinib 200 mg [FIL200] or 100 mg [FIL100], were randomized to treatment withdrawal [placebo] during maintenance, and following disease worsening, were re-treated with open-label FIL200 in the LTE study. Factors were evaluated for association with pMCS remission at LTE week 12, and safety outcomes were reported. RESULTS Analyses included 86 patients [FIL200: n = 51; FIL100: n = 35]. Median time to disease worsening following treatment withdrawal was 15.1 weeks (95% confidence interval [CI]: 9.1-18.7) for FIL200-induced patients and 9.6 weeks [95% CI: 6.3-12.0] for FIL100-induced patients. Three-quarters [75%] of patients achieved a pMCS response within 4-5 weeks of re-treatment in both groups. At LTE week 48, pMCS remission was achieved by 45.1% and 51.4% of FIL200- and FIL100-induced patients, respectively. Factors independently associated with restoring efficacy included no concomitant use of corticosteroids at induction baseline, and high albumin levels, pMCS remission and endoscopic score at maintenance baseline. No new safety signals were reported among re-treated patients. CONCLUSIONS In induction responders, re-treatment with FIL200 following temporary withdrawal from therapy restores response and/or remission in the majority of patients within 12 weeks. Re-treatment is well-tolerated

    FLT3 mutations in Early T-Cell Precursor ALL characterize a stem cell like leukemia and imply the clinical use of tyrosine kinase inhibitors

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    Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) has been identified as high-risk subgroup of acute T-lymphoblastic leukemia (T-ALL) with a high rate of FLT3-mutations in adults. To unravel the underlying pathomechanisms and the clinical course we assessed molecular alterations and clinical characteristics in a large cohort of ETP-ALL (n = 68) in comparison to non-ETP T-ALL adult patients. Interestingly, we found a high rate of FLT3-mutations in ETP-ALL samples (n = 24, 35%). Furthermore, FLT3 mutated ETP-ALL was characterized by a specific immunophenotype (CD2+/CD5-/CD13+/CD33-), a distinct gene expression pattern (aberrant expression of IGFBP7, WT1, GATA3) and mutational status (absence of NOTCH1 mutations and a low frequency, 21%, of clonal TCR rearrangements). The observed low GATA3 expression and high WT1 expression in combination with lack of NOTCH1 mutations and a low rate of TCR rearrangements point to a leukemic transformation at the pluripotent prothymocyte stage in FLT3 mutated ETP-ALL. The clinical outcome in ETP-ALL patients was poor, but encouraging in those patients with allogeneic stem cell transplantation (3-year OS: 74%). To further explore the efficacy of targeted therapies, we demonstrate that T-ALL cell lines transfected with FLT3 expression constructs were particularly sensitive to tyrosine kinase inhibitors. In conclusion, FLT3 mutated ETP-ALL defines a molecular distinct stem cell like leukemic subtype. These data warrant clinical studies with the implementation of FLT3 inhibitors in addition to early allogeneic stem cell transplantation for this high risk subgroup

    Two-spinon dynamic structure factor of the one-dimensional S=1/2 Heisenberg antiferromagnet

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    The exact expression derived by Bougourzi, Couture, and Kacir for the 2-spinon contribution to the dynamic spin structure factor Szz(q,ω)S_{zz}(q,\omega) of he one-dimensional SS=1/2 Heisenberg antiferromagnet at T=0T=0 is evaluated for direct comparison with finite-chain transition rates (N≤28N\leq 28) and an approximate analytical result previously inferred from finite-NN data, sum rules, and Bethe-ansatz calculations. The 2-spinon excitations account for 72.89% of the total intensity in Szz(q,ω)S_{zz}(q,\omega). The singularity structure of the exact result is determined analytically and its spectral-weight distribution evaluated numerically over the entire range of the 2-spinon continuum. The leading singularities of the frequency-dependent spin autocorrelation function, static spin structure factor, and qq-dependent susceptibility are determined via sum rules.Comment: 6 pages (RevTex) and 5 figures (Postscript
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