1,281 research outputs found

    A Mathematical Formulation for MIMO Channel Map

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    Channel map has been widely used as an effective tool in network planning and deployment. However, there is a lack of mathematical formulation of the channel map as a tool for multiple-input multiple-output (MIMO) networks planning. In this work, we define and construct a MIMO channel map based on the extension of a mathematical formulation for the conventional single antenna channel map. We demonstrate the effectiveness of the constructed MIMO channel map in planning a distributed MIMO channel network through a numerical example. The results show that location optimisation in distributed MIMO systems gains significantly from an abstract formulation of the channel map

    Measurement of \psip Radiative Decays

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    Using 14 million psi(2S) events accumulated at the BESII detector, we report first measurements of branching fractions or upper limits for psi(2S) decays into gamma ppbar, gamma 2(pi^+pi^-), gamma K_s K^-pi^++c.c., gamma K^+ K^- pi^+pi^-, gamma K^{*0} K^- pi^+ +c.c., gamma K^{*0}\bar K^{*0}, gamma pi^+pi^- p pbar, gamma 2(K^+K^-), gamma 3(pi^+pi^-), and gamma 2(pi^+pi^-)K^+K^- with the invariant mass of hadrons below 2.9GeV/c^2. We also report branching fractions of psi(2S) decays into 2(pi^+pi^-) pi^0, omega pi^+pi^-, omega f_2(1270), b_1^\pm pi^\mp, and pi^0 2(pi^+pi^-) K^+K^-.Comment: 5 pages, 4 figure

    Observation of Y(2175) in J/Οˆβ†’Ξ·Ο•f0(980)J/\psi\to \eta\phi f_0(980)

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    The decays of J/Οˆβ†’Ξ·Ο•f0(980)(Ξ·β†’Ξ³Ξ³,Ο•β†’K+Kβˆ’,f0(980)β†’Ο€+Ο€βˆ’)J/\psi\to \eta\phi f_0(980) (\eta\to \gamma\gamma, \phi \to K^+K^-, f_0(980)\to\pi^+\pi^-) are analyzed using a sample of 5.8Γ—1075.8 \times 10^{7} J/ψJ/\psi events collected with the BESII detector at the Beijing Electron-Positron Collider (BEPC). A structure at around 2.182.18 GeV/c2c^2 with about 5Οƒ5\sigma significance is observed in the Ο•f0(980)\phi f_0(980) invariant mass spectrum. A fit with a Breit-Wigner function gives the peak mass and width of m=2.186Β±0.010(stat)Β±0.006(syst)m=2.186\pm 0.010 (stat)\pm 0.006 (syst) GeV/c2c^2 and Ξ“=0.065Β±0.023(stat)Β±0.017(syst)\Gamma=0.065\pm 0.023 (stat)\pm 0.017 (syst) GeV/c2c^2, respectively, that are consistent with those of Y(2175), observed by the BABAR collaboration in the initial-state radiation (ISR) process e+eβˆ’β†’Ξ³ISRΟ•f0(980)e^+e^-\to\gamma_{ISR}\phi f_0(980). The production branching ratio is determined to be Br(J/Οˆβ†’Ξ·Y(2175))β‹…Br(Y(2175)β†’Ο•f0(980))β‹…Br(f0(980)β†’Ο€+Ο€βˆ’)=(3.23Β±0.75(stat)Β±0.73(syst))Γ—10βˆ’4Br(J/\psi\to\eta Y(2175))\cdot Br(Y(2175)\to\phi f_0(980))\cdot Br(f_0(980)\to\pi^+\pi^-)=(3.23\pm 0.75 (stat)\pm0.73 (syst))\times 10^{-4}, assuming that the Y(2175) is a 1βˆ’βˆ’1^{--} state.Comment: 5 pages, 4 figures, accepted by Phys. Rev. Let

    Measurements of J/ψJ/\psi and ψ(2S)\psi(2S) decays into ΛΛˉπ0\Lambda \bar{\Lambda}\pi^0 and ΛΛˉη\Lambda \bar{\Lambda}\eta

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    Using 58 million J/ψJ/\psi and 14 million ψ(2S)\psi(2S) events collected by the BESII detector at the BEPC, branching fractions or upper limits for the decays J/ψJ/\psi and ψ(2S)→ΛΛˉπ0\psi(2S) \to \Lambda \bar{\Lambda}\pi^0 and ΛΛˉη\Lambda \bar{\Lambda}\eta are measured. For the isospin violating decays, the upper limits are determined to be B(J/Οˆβ†’Ξ›Ξ›Λ‰Ο€0)<6.4Γ—10βˆ’5{\cal B}(J/\psi \to \Lambda \bar{\Lambda}\pi^0)<6.4\times 10^{-5} and B(ψ(2S)→ΛΛˉπ0)<4.9Γ—10βˆ’5{\cal B}(\psi(2S) \to \Lambda \bar{\Lambda}\pi^0)<4.9\times 10^{-5} at the 90% confidence level. The isospin conserving process J/Οˆβ†’Ξ›Ξ›Λ‰Ξ·J/\psi \to \Lambda \bar{\Lambda}\eta is observed for the first time, and its branching fraction is measured to be B(J/Οˆβ†’Ξ›Ξ›Λ‰Ξ·)=(2.62Β±0.60Β±0.44)Γ—10βˆ’4{\cal B}(J/\psi \to \Lambda \bar{\Lambda}\eta)=(2.62\pm 0.60\pm 0.44)\times 10^{-4}, where the first error is statistical and the second one is systematic. No ΛΛˉη\Lambda \bar{\Lambda}\eta signal is observed in ψ(2S)\psi(2S) decays, and B(ψ(2S)→ΛΛˉη)<1.2Γ—10βˆ’4{\cal B}(\psi(2S) \to \Lambda \bar{\Lambda}\eta)<1.2\times 10^{-4} is set at the 90% confidence level. Branching fractions of J/ψJ/\psi decays into Ξ£+Ο€βˆ’barΞ›\Sigma^+ \pi^- bar{\Lambda} and Ξ£Λ‰βˆ’Ο€+Ξ›\bar{\Sigma}^- \pi^+ \Lambda are also reported, and the sum of these branching fractions is determined to be B(J/Οˆβ†’Ξ£+Ο€βˆ’Ξ›Λ‰+c.c.)=(1.52Β±0.08Β±0.16)Γ—10βˆ’3{\cal B}(J/\psi \to \Sigma^+\pi^- \bar{\Lambda} + c.c.)=(1.52\pm 0.08\pm 0.16)\times 10^{-3}.Comment: 7 pages, 10 figures. Phys.Rev.D comments considere

    Developmental changes in the role of different metalinguistic awareness skills in Chinese reading acquisition from preschool to third grade

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    Copyright @ 2014 Wei et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The present study investigated the relationship between Chinese reading skills and metalinguistic awareness skills such as phonological, morphological, and orthographic awareness for 101 Preschool, 94 Grade-1, 98 Grade-2, and 98 Grade-3 children from two primary schools in Mainland China. The aim of the study was to examine how each of these metalinguistic awareness skills would exert their influence on the success of reading in Chinese with age. The results showed that all three metalinguistic awareness skills significantly predicted reading success. It further revealed that orthographic awareness played a dominant role in the early stages of reading acquisition, and its influence decreased with age, while the opposite was true for the contribution of morphological awareness. The results were in stark contrast with studies in English, where phonological awareness is typically shown as the single most potent metalinguistic awareness factor in literacy acquisition. In order to account for the current data, a three-stage model of reading acquisition in Chinese is discussed.National Natural Science Foundation of China and Knowledge Innovation Program of the Chinese Academy of Sciences

    Impacts of MicroRNA Gene Polymorphisms on the Susceptibility of Environmental Factors Leading to Carcinogenesis in Oral Cancer

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    BACKGROUND: MicroRNAs (miRNAs) have been regarded as a critical factor in targeting oncogenes or tumor suppressor genes in tumorigenesis. The genetic predisposition of miRNAs-signaling pathways related to the development of oral squamous cell carcinoma (OSCC) remains unresolved. This study examined the associations of polymorphisms with four miRNAs with the susceptibility and clinicopathological characteristics of OSCC. METHODOLOGY/PRINCIPAL FINDINGS: A total of 895 male subjects, including 425 controls and 470 male oral cancer patients, were selected. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and real-time PCR were used to analyze miRNA146a, miRNA196, miRNA499 and miRNA149 genetic polymorphisms between the control group and the case group. This study determined that a significant association of miRNA499 with CC genotype, as compared to the subjects with TT genotype, had a higher risk (AORβ€Š=β€Š4.52, 95% CIβ€Š=β€Š1.24-16.48) of OSCC. Moreover, an impact of those four miRNAs gene polymorphism on the susceptibility of betel nut and tobacco consumption leading to oral cancer was also revealed. We found a protective effect between clinical stage development (AORβ€Š=β€Š0.58, 95% CIβ€Š=β€Š0.36-0.94) and the tumor size growth (AORβ€Š=β€Š0.47, 95% CIβ€Š=β€Š0.28-0.79) in younger patients (age<60). CONCLUSIONS: Our results suggest that genetic polymorphism of miRNA499 is associated with oral carcinogenesis, and the interaction of the miRNAs genetic polymorphism and environmental carcinogens is also related to an increased risk of oral cancer in Taiwanese

    Measurements of the observed cross sections for e+eβˆ’β†’e^+e^-\to exclusive light hadrons containing Ο€0Ο€0\pi^0\pi^0 at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV

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    By analyzing the data sets of 17.3, 6.5 and 1.0 pbβˆ’1^{-1} taken, respectively, at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for e+eβˆ’β†’Ο€+Ο€βˆ’Ο€0Ο€0e^+e^-\to \pi^+\pi^-\pi^0\pi^0, K+Kβˆ’Ο€0Ο€0K^+K^-\pi^0\pi^0, 2(Ο€+Ο€βˆ’Ο€0)2(\pi^+\pi^-\pi^0), K+Kβˆ’Ο€+Ο€βˆ’Ο€0Ο€0K^+K^-\pi^+\pi^-\pi^0\pi^0 and 3(Ο€+Ο€βˆ’)Ο€0Ο€03(\pi^+\pi^-)\pi^0\pi^0 at the three energy points. Based on these cross sections we set the upper limits on the observed cross sections and the branching fractions for ψ(3770)\psi(3770) decay into these final states at 90% C.L..Comment: 7 pages, 2 figure

    Partial wave analysis of J/\psi \to \gamma \phi \phi

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    Using 5.8Γ—107J/ψ5.8 \times 10^7 J/\psi events collected in the BESII detector, the radiative decay J/Οˆβ†’Ξ³Ο•Ο•β†’Ξ³K+Kβˆ’KS0KL0J/\psi \to \gamma \phi \phi \to \gamma K^+ K^- K^0_S K^0_L is studied. The ϕϕ\phi\phi invariant mass distribution exhibits a near-threshold enhancement that peaks around 2.24 GeV/c2c^{2}. A partial wave analysis shows that the structure is dominated by a 0βˆ’+0^{-+} state (Ξ·(2225)\eta(2225)) with a mass of 2.24βˆ’0.02+0.03βˆ’0.02+0.032.24^{+0.03}_{-0.02}{}^{+0.03}_{-0.02} GeV/c2c^{2} and a width of 0.19Β±0.03βˆ’0.04+0.060.19 \pm 0.03^{+0.06}_{-0.04} GeV/c2c^{2}. The product branching fraction is: Br(J/Οˆβ†’Ξ³Ξ·(2225))β‹…Br(Ξ·(2225)→ϕϕ)=(4.4Β±0.4Β±0.8)Γ—10βˆ’4Br(J/\psi \to \gamma \eta(2225))\cdot Br(\eta(2225)\to \phi\phi) = (4.4 \pm 0.4 \pm 0.8)\times 10^{-4}.Comment: 11 pages, 4 figures. corrected proof for journa

    Direct Measurements of Absolute Branching Fractions for D0 and D+ Inclusive Semimuonic Decays

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    By analyzing about 33 pbβˆ’1\rm pb^{-1} data sample collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, we directly measure the branching fractions for the neutral and charged DD inclusive semimuonic decays to be BF(D0β†’ΞΌ+X)=(6.8Β±1.5Β±0.7)BF(D^0 \to \mu^+ X) =(6.8\pm 1.5\pm 0.7)% and BF(D+β†’ΞΌ+X)=(17.6Β±2.7Β±1.8)BF(D^+ \to \mu^+ X) =(17.6 \pm 2.7 \pm 1.8)%, and determine the ratio of the two branching fractions to be BF(D+β†’ΞΌ+X)BF(D0β†’ΞΌ+X)=2.59Β±0.70Β±0.25\frac{BF(D^+ \to \mu^+ X)}{BF(D^0 \to \mu^+ X)}=2.59\pm 0.70 \pm 0.25

    Measurements of the observed cross sections for exclusive light hadron production in e^+e^- annihilation at \sqrt{s}= 3.773 and 3.650 GeV

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    By analyzing the data sets of 17.3 pbβˆ’1^{-1} taken at s=3.773\sqrt{s}=3.773 GeV and 6.5 pbβˆ’1^{-1} taken at s=3.650\sqrt{s}=3.650 GeV with the BESII detector at the BEPC collider, we have measured the observed cross sections for 12 exclusive light hadron final states produced in e+eβˆ’e^+e^- annihilation at the two energy points. We have also set the upper limits on the observed cross sections and the branching fractions for ψ(3770)\psi(3770) decay to these final states at 90% C.L.Comment: 8 pages, 5 figur
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