970 research outputs found

    Optimal Las Vegas Locality Sensitive Data Structures

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    We show that approximate similarity (near neighbour) search can be solved in high dimensions with performance matching state of the art (data independent) Locality Sensitive Hashing, but with a guarantee of no false negatives. Specifically, we give two data structures for common problems. For cc-approximate near neighbour in Hamming space we get query time dn1/c+o(1)dn^{1/c+o(1)} and space dn1+1/c+o(1)dn^{1+1/c+o(1)} matching that of \cite{indyk1998approximate} and answering a long standing open question from~\cite{indyk2000dimensionality} and~\cite{pagh2016locality} in the affirmative. By means of a new deterministic reduction from 1\ell_1 to Hamming we also solve 1\ell_1 and 2\ell_2 with query time d2n1/c+o(1)d^2n^{1/c+o(1)} and space d2n1+1/c+o(1)d^2 n^{1+1/c+o(1)}. For (s1,s2)(s_1,s_2)-approximate Jaccard similarity we get query time dnρ+o(1)dn^{\rho+o(1)} and space dn1+ρ+o(1)dn^{1+\rho+o(1)}, ρ=log1+s12s1/log1+s22s2\rho=\log\frac{1+s_1}{2s_1}\big/\log\frac{1+s_2}{2s_2}, when sets have equal size, matching the performance of~\cite{tobias2016}. The algorithms are based on space partitions, as with classic LSH, but we construct these using a combination of brute force, tensoring, perfect hashing and splitter functions \`a la~\cite{naor1995splitters}. We also show a new dimensionality reduction lemma with 1-sided error

    Bulk Properties in Au+Au Collisions at sNN\sqrt{s_{NN}} = 9.2 GeV in STAR Experiment at RHIC

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    One of the primary goals of high-energy heavy-ion collisions is to establish the QCD phase diagram and search for possible phase boundaries. The planned RHIC energy scan program will explore this exciting physics topic using heavy-ion collisions at various center of mass energies. The first test run with Au+Au collisions at sNN\sqrt{s_{NN}} = 9.2 GeV took place in early 2008. We present the results on identified particle ratios, azimuthal anisotropy parameters (v1 and v2) and HBT at midrapidity using data from this run. These results are compared to data for both lower and higher center of mass energies at the AGS, SPS and RHIC. These new data demonstrate the capabilities of the STAR detector for exploring the QCD phase diagram.Comment: 4 pages, 2 figures: Re-submitted to appear in proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

    Mid-rapidity π±\pi^\pm, K±K^\pm, and pˉ\bar{p} spectra and particle ratios from STAR

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    Results are presented on π±\pi^\pm, K±K^\pm, and pˉ\bar{p} transverse mass spectra and particle multiplicity ratios at mid-rapidity in Au+Au collisions at sNN\sqrt{s_{_{\rm NN}}}=130 and 200 GeV and in p+p collisions at s\sqrt{s}=200 GeV. Comparisons are made to results from lower energies. The bulk properties of the collision inferred from these results are discussed.Comment: 4 pages, 3 figures, Talk presented at Quark Matter 2002, Nantes, France, July 200

    Correlation between the charged kaon ratio and the baryon phase-space density in heavy-ion collisions

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    It is found that the baryon phase-space density obtained from the ratio of deuteron to proton yields is nearly constant over centrality in Au+Au collisions at the AGS. The finding offers an explanation for the puzzling centrality independence of the ratio of charged kaon total yields. The correlation between the charged kaon ratio and the average baryon phase-space density is studied for central heavy-ion collisions of various systems over a wide range of beam energy. It is found that the charged kaon ratio and the average baryon phase-space density both increase with decreasing beam energy, and are strongly correlated. Such study may provide a new approach to search for medium effect on the kaon mass.Comment: 5 pages, 3 figures, 1 table in revtex styl

    Intravascular Large B-Cell Lymphoma Presenting as Dementia and Hemolytic Anemia

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    Background: Intravascular lymphoma (IVL) is an uncommon disease characterized by atypical lymphoid cells growing inside the lumina of small vessels. The diversity of clinical presentation due to possible involvement of multiple organs often complicates its diagnosis. Case Report: Here, we report on a case of IVL with rapidly progressive dementia and Coombs-negative hemolytic anemia. Interestingly, the erythrocytes exhibited a decreased osmotic resistance. Bone marrow histopathology revealed increased erythropoiesis and, finally, a small monoclonal B lymphocyte population. Cerebral magnetic resonance imaging (MRI) demonstrated few micro-bleedings. Computed tomography (CT) showed bilateral ground-glass opacity of the lungs. Within a few days, the patient developed respiratory failure and died. On post-mortem examination, intravascular large B-cell lymphoma with almost complete infiltration of the brain and lungs was diagnosed. Conclusion: IVL should be considered early in situations of unexplained neuropsychiatric disease along with markedly elevated levels of lactic dehydrogenase, anemia, and hemolysis

    Collective Flow Distributions and Nuclear Stopping in Heavy-ion Collisions at AGS, SPS and RHIC

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    We study the production of proton, antiproton and net-proton at \AGS, \SPS and \RHIC within the framework non-uniform flow model(NUFM) in this paper. It is found that the system of RHIC has stronger longitudinally non-uniform feature than AGS and SPS, which means that nuclei at RHIC energy region is much more transparent. The NUFM model provides a very good description of all proton rapidity at whole AGS, SPS and RHIC. It is shown that our analysis relates closely to the study of nuclear stopping and longitudinally non-uniform flow distribution of experiment. This comparison with AGS and SPS help us to understand the feature of particle stopping of thermal freeze-out at RHIC experiment.Comment: 16 pages,7 figure
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