154 research outputs found

    Commissioning and performance of a phase-compensated optical link for the AWAKE experiment at CERN

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    In this work, we analyze the performance of the solution adopted for the compensation of the phase drift of a 3 km optical fiber link used for the AWAKE experiment at CERN. The link is devoted to transmit the reference signals used to synchronize the SPS beam with the experiment to have a fixed phase relation, regardless of the external conditions of the electronics and the link itself. The system has been operating for more than a year without observed drift in the beam phases. Specific measurements have proven that the jitter introduced by the system is lower than 0.6 ps and the maximum phase drift of the link is at the picosecond level.Comment: Poster presented at LLRF Workshop 2017 (LLRF2017, arXiv:1803.07677

    A case report of metastasis of malignant mesothelioma to the oral gingiva

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    Introduction: Metastatic mesothelioma to the oral cavity arises from the pleura or peritoneum and distant hematogenous metastases are seen in more than half of cases but only a few cases are reported to the oral cavity Case: A 75 year old male suffering from metastatic mesothelioma presents an hyperplasia of the attached gingiva. Malignant mesothelioma is a rare tumour arising from pleura, pericardium or peritoneum. Conclusion: This article highlights the importance of biopsy and histopathological diagnosis of oral lesions especially in case of a malignant history

    Integrable models and quantum spin ladders: comparison between theory and experiment for the strong coupling ladder compounds

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    (abbreviated) This article considers recent advances in the investigation of the thermal and magnetic properties of integrable spin ladder models and their applicability to the physics of real compounds. The ground state properties of the integrable two-leg spin-1/2 and the mixed spin-(1/2,1) ladder models at zero temperature are analyzed by means of the Thermodynamic Bethe Ansatz. Solving the TBA equations yields exact results for the critical fields and critical behaviour. The thermal and magnetic properties of the models are investigated in terms of the recently introduced High Temperature Expansion method, which is discussed in detail. It is shown that in the strong coupling limit the integrable spin-1/2 ladder model exhibits three quantum phases: (i) a gapped phase in the regime H<Hc1H<H_{c1}, (ii) a fully polarised phase for H>Hc2H>H_{c2}, and (iii) a Luttinger liquid magnetic phase in the regime Hc1<H<Hc2H_{c1}<H<H_{c2}. The critical behaviour in the vicinity of the critical points is of the Pokrovsky-Talapov type. The temperature-dependent thermal and magnetic properties are directly evaluated from the exact free energy expression and compared to known experimental results for a range of strong coupling ladder compounds. Similar analysis of the mixed spin-(1/2,1) ladder model reveals a rich phase diagram, with a 1/3 and a full saturation magnetisation plateau within the strong antiferromagnetic rung coupling regime. For weak rung coupling, the fractional magnetisation plateau is diminished and a new quantum phase transition occurs. The phase diagram can be directly deduced from the magnetisation curve obtained from the exact result derived from the HTE. The thermodynamics of the spin-orbital model with different single-ion anisotropies is also investigated.Comment: 90 pages, 33 figures, extensive revisio

    Probabilistic models of information retrieval based on measuring the divergence from randomness

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    We introduce and create a framework for deriving probabilistic models of Information Retrieval. The models are nonparametric models of IR obtained in the language model approach. We derive term-weighting models by measuring the divergence of the actual term distribution from that obtained under a random process. Among the random processes we study the binomial distribution and Bose--Einstein statistics. We define two types of term frequency normalization for tuning term weights in the document--query matching process. The first normalization assumes that documents have the same length and measures the information gain with the observed term once it has been accepted as a good descriptor of the observed document. The second normalization is related to the document length and to other statistics. These two normalization methods are applied to the basic models in succession to obtain weighting formulae. Results show that our framework produces different nonparametric models forming baseline alternatives to the standard tf-idf model

    Progress with the Upgrade of the SPS for the HL-LHC Era

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    The demanding beam performance requirements of the High Luminosity (HL-) LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed.Comment: 3 p. Presented at 4th International Particle Accelerator Conference (IPAC 2013

    Entanglement entropy of two disjoint intervals in c=1 theories

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    We study the scaling of the Renyi entanglement entropy of two disjoint blocks of critical lattice models described by conformal field theories with central charge c=1. We provide the analytic conformal field theory result for the second order Renyi entropy for a free boson compactified on an orbifold describing the scaling limit of the Ashkin-Teller (AT) model on the self-dual line. We have checked this prediction in cluster Monte Carlo simulations of the classical two dimensional AT model. We have also performed extensive numerical simulations of the anisotropic Heisenberg quantum spin-chain with tree-tensor network techniques that allowed to obtain the reduced density matrices of disjoint blocks of the spin-chain and to check the correctness of the predictions for Renyi and entanglement entropies from conformal field theory. In order to match these predictions, we have extrapolated the numerical results by properly taking into account the corrections induced by the finite length of the blocks to the leading scaling behavior.Comment: 37 pages, 23 figure

    Accurate and Transparent Path Prediction Using Process Mining

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    Anticipating the next events of an ongoing series of activities has many compelling applications in various industries. It can be used to improve customer satisfaction, to enhance operational efficiency, and to streamline health-care services, to name a few. In this work, we propose an algorithm that predicts the next events by leveraging business process models obtained using process mining techniques. Because we are using business process models to build the predictions, it allows business analysts to interpret and alter the predictions. We tested our approach with more than 30 synthetic datasets as well as 6 real datasets. The results have superior accuracy compared to using neural networks while being orders of magnitude faster

    Life expectancy and agricultural environmental impacts in Addis Ababa can be improved through optimized plant and animal protein consumption

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    In Ethiopia, children and adults face a double burden of malnutrition, with undernutrition and stunting coexisting with non-communicable diseases. Here we use a framework of comparative risk assessment, local dietary surveys and relative risks from large observational studies to quantify the health and environmental impacts of meeting adult and child recommended daily protein intakes in urban Addis Ababa. We find that plant-based foods, especially legumes, would have the lowest environmental impact and substantially increase life expectancy in adults, while animal-source proteins could be beneficial for children. This context-specific approach—accounting for regional constraints and trade-offs—could aid policymakers in developing culturally appropriate, nutritionally adequate and sustainable dietary recommendations
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