4,801 research outputs found

    A new perspective on GCRT J1745-3009

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    Two WSRT observations were performed and five archival VLA data were reduced in order to redetect the enigmatic radio transient GCRT J1745-3009. The source was not redetected. We were, however, able to extract important new information from the discovery dataset. Our reanalysis excludes models that predict symmetric bursts, but the transient white dwarf pulsar is favoured. Although we now have more contraints on the properties of this source, we are still unsure about its basic model.Comment: 11 pages, 5 figure

    Actively Contracting Bundles of Polar Filaments

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    We introduce a phenomenological model to study the properties of bundles of polar filaments which interact via active elements. The stability of the homogeneous state, the attractors of the dynamics in the unstable regime and the tensile stress generated in the bundle are discussed. We find that the interaction of parallel filaments can induce unstable behavior and is responsible for active contraction and tension in the bundle. Interaction between antiparallel filaments leads to filament sorting. Our model could apply to simple contractile structures in cells such as stress fibers.Comment: 4 pages, 4 figures, RevTex, to appear in Phys. Rev. Let

    Percolation Transition in the random antiferromagnetic spin-1 chain

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    We give a physical description in terms of percolation theory of the phase transition that occurs when the disorder increases in the random antiferromagnetic spin-1 chain between a gapless phase with topological order and a random singlet phase. We study the statistical properties of the percolation clusters by numerical simulations, and we compute exact exponents characterizing the transition by a real-space renormalization group calculation.Comment: 9 pages, 4 encapsulated Postscript figures, REVTeX 3.

    Challenging the orthodoxy: union learning representatives as organic intellectuals

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    Teacher education and continuing professional development have become a key areas of controversy in England since the period of school sector restructuring following the 1988 Education Reform Act. More recently teacher training and professional development have often been used to promote and reinforce a narrow focus on the government’s ‘standards agenda’. However, the emerging discourse of ‘new professionalism’ has raised the profile of professional development in schools, and together with union learning representatives, there are opportunities to secure real improvements in teachers’ access to continuing professional development. This paper argues however that union learning representatives must go beyond advocating for better access to professional development and should raise more fundamental questions about the nature of professional development and the education system it serves. Drawing on Gramsci’s notion of the ‘organic intellectual’, the paper argues that union learning representatives have a key role as organisers of ideas – creating spaces in which the ideological dominance of current policy orthodoxy might be challenged

    Safety and Tolerability of PD‐1/PD‐L1 Inhibitors Compared with Chemotherapy in Patients with Advanced Cancer: A Meta‐Analysis

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    BACKGROUND: Compared with chemotherapy, significant improvement in survival outcomes with the programmed death receptor-1 (PD-1) inhibitors nivolumab and pembrolizumab and the programmed death-ligand 1 (PD-L1) inhibitor atezolizumab has been shown in several types of advanced solid tumors. We conducted a systematic review and meta-analysis to compare safety and tolerability between PD-1/PD-L1 inhibitors and chemotherapy. METHODS: PubMed and American Society of Clinical Oncology (ASCO) databases were searched 1966 to September 2016. Eligible studies included randomized controlled trials (RCTs) comparing single-agent U.S. Food and Drug Administration-approved PD-1/PD-L1 inhibitors (nivolumab, pembrolizumab, or atezolizumab) with chemotherapy in cancer patients reporting any all-grade (1-4) or high-grade (3-4) adverse events (AEs), all- or high-grade treatment-related symptoms, hematologic toxicities and immune-related AEs, treatment discontinuation due to toxicities, or treatment-related deaths. The summary incidence, relative risk, and 95% confidence intervals were calculated. RESULTS: A total of 3,450 patients from 7 RCTs were included in the meta-analysis: 4 nivolumab, 2 pembrolizumab, and 1 atezolizumab trials. The underlying malignancies included were non-small cell lung cancer (4 trials) and melanoma (3 trials). Compared with chemotherapy, the PD-1/PD-L1 inhibitors had a significantly lower risk of all- and high-grade fatigue, sensory neuropathy, diarrhea and hematologic toxicities, all-grade anorexia, nausea, and constipation, any all- and high-grade AEs, and treatment discontinuation. There was an increased risk of all-grade rash, pruritus, colitis, aminotransferase elevations, hypothyroidism, and hyperthyroidism, and all- and high-grade pneumonitis with PD1/PD-L1 inhibitors. CONCLUSION: PD-1/PD-L1 inhibitors are overall better tolerated than chemotherapy. Our results provide further evidence supporting the favorable risk/benefit ratio for PD-1/PD-L1 inhibitors. The Oncologist 2017;22:470-479 IMPLICATIONS FOR PRACTICE: We conducted a systematic review and meta-analysis to compare summary toxicity endpoints and clinically relevant adverse events between programmed death receptor-1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors and chemotherapy. PD1/PD-L1 inhibitors were associated with a lower risk of treatment-related symptoms (fatigue, anorexia, nausea, diarrhea, constipation, and sensory neuropathy) but a higher risk of immune-related adverse events (AEs). Summary toxicity endpoints favor PD1/PD-L1 inhibitors (any all- and high-grade AEs and treatment discontinuation). PD1/PD-L1 inhibitors are overall better tolerated than chemotherapy. In addition to efficacy data from trials, our findings provide useful information for clinicians for well-balanced discussions with their patients on the risks and benefits of treatment options for advanced cancer

    A Tribute to Robert B. Fleming

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    Occupational Therapy for Adults With Cancer: Why It Matters

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    Adults with cancer may be at risk for limitations in functional status and quality of life (QOL). Occupational therapy is a supportive service with the specific mission to help people functionally engage in life as safely and independently as possible with the primary goal of improving QOL. Unfortunately, for people with cancer, occupational therapy remains underused. The overall purpose of this review is to provide an understanding of what occupational therapy is and its relevance to patients with cancer, highlight the reasons to refer, and, last, provide general advice on how to access services

    Numerical renormalization-group study of spin correlations in one-dimensional random spin chains

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    We calculate the ground-state two-spin correlation functions of spin-1/2 quantum Heisenberg chains with random exchange couplings using the real-space renormalization group scheme. We extend the conventional scheme to take account of the contribution of local higher multiplet excitations in each decimation step. This extended scheme can provide highly accurate numerical data for large systems. The random average of staggered spin correlations of the chains with random antiferromagnetic (AF) couplings shows algebraic decay like 1/r21/r^2, which verifies the Fisher's analytic results. For chains with random ferromagnetic (FM) and AF couplings, the random average of generalized staggered correlations is found to decay more slowly than a power-law, in the form close to 1/ln⁥(r)1/\ln(r). The difference between the distribution functions of the spin correlations of the random AF chains and of the random FM-AF chains is also discussed.Comment: 14 pages including 8 figures, REVTeX, submitted to Physical Review

    Density Matrix Renormalization Group Study of the Haldane Phase in Random One-Dimensional Antiferromagnets

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    It is conjectured that the Haldane phase of the S=1 antiferromagnetic Heisenberg chain and the S=1/2S=1/2 ferromagnetic-antiferromagnetic alternating Heisenberg chain is stable against any strength of randomness, because of imposed breakdown of translational symmetry. This conjecture is confirmed by the density matrix renormalization group calculation of the string order parameter and the energy gap distribution.Comment: 4 Pages, 7 figures; Considerable revisions are made in abstract and main text. Final accepted versio
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