90 research outputs found

    Search for extraterrestrial antineutrino sources with the KamLAND detector

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    We present the results of a search for extraterrestrial electron antineutrinos (νˉe\bar{\nu}_{e}'s) in the energy range 8.3MeV<Eνˉe<31.8MeV8.3 MeV < E_{\bar{\nu}_{e}} < 31.8 MeV using the KamLAND detector. In an exposure of 4.53 kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting an upper limit on the probability of 8^{8}B solar νe\nu_{e}'s converting into νˉe\bar{\nu}_{e}'s at 5.3×1055.3 \times 10^{-5} (90% C.L.), if we assume an undistorted νˉe\bar{\nu}_{e} shape. This limit corresponds to a solar νˉe\bar{\nu}_{e} flux of 93cm2s193 cm^{-2} s^{-1} or an event rate of 1.6events(ktonyear)11.6 events (kton-year)^{-1} above the energy threshold (Eνˉe>8.3MeV)(E_{\bar{\nu}_{e}} > 8.3 MeV). The present data also allows us to set more stringent limits on the diffuse supernova neutrino flux and on the annihilation rates for light dark matter particles.Comment: 22 pages, 6 figure

    Measurement of the 8B Solar Neutrino Flux with the KamLAND Liquid Scintillator Detector

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    We report a measurement of the neutrino-electron elastic scattering rate from 8B solar neutrinos based on a 123 kton-day exposure of KamLAND. The background-subtracted electron recoil rate, above a 5.5 MeV analysis threshold is 1.49+/-0.14(stat)+/-0.17(syst) events per kton-day. Interpreted as due to a pure electron flavor flux with a 8B neutrino spectrum, this corresponds to a spectrum integrated flux of 2.77+/-0.26(stat)+/-0.32(syst) x 10^6 cm^-2s^-1. The analysis threshold is driven by 208Tl present in the liquid scintillator, and the main source of systematic uncertainty is due to background from cosmogenic 11Be. The measured rate is consistent with existing measurements and with Standard Solar Model predictions which include matter enhanced neutrino oscillation.Comment: 6 pages, 3 figure

    Immuno-surgical management of pancreatic cancer with analysis of cancer exosomes

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    Exosomes (EXs), a type of extracellular vesicles secreted from various cells and especially cancer cells, mesenchymal cells, macrophages and other cells in the tumor microenvironment (TME), are involved in biologically malignant behaviors of cancers. Recent studies have revealed that EXs contain microRNAs on their inside and express proteins and glycolipids on their outsides, every component of which plays a role in the transmission of genetic and/or epigenetic information in cell-to-cell communications. It is also known that miRNAs are involved in the signal transduction. Thus, EXs may be useful for monitoring the TME of tumor tissues and the invasion and metastasis, processes that are associated with patient survival. Because several solid tumors secrete immune checkpoint proteins, including programmed cell death-ligand 1, the EX-mediated mechanisms are suggested to be potent targets for monitoring patients. Therefore, a companion therapeutic approach against cancer metastasis to distant organs is proposed when surgical removal of the primary tumor is performed. However, EXs and immune checkpoint mechanisms in pancreatic cancer are not fully understood, we provide an update on the recent advances in this field and evidence that EXs will be useful for maximizing patient benefit in precision medicine

    Constraints on θ13\theta_{13} from A Three-Flavor Oscillation Analysis of Reactor Antineutrinos at KamLAND

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    We present new constraints on the neutrino oscillation parameters /textyenDeltam212/textyen Delta m^{2}_{21}, /textyentheta12/textyen theta_{12}, and /textyentheta13/textyen theta_{13} from a three-flavor analysis of solar and KamLAND data. The KamLAND data set includes data acquired following a radiopurity upgrade and amounts to a total exposure of 3.49 \textyen times 10^{32} target-proton-year. Under the assumption of {\textyen it CPT} invariance, a two-flavor analysis (/textyen mbox{\textyen theta_{13} = 0}) of the KamLAND and solar data yields the best-fit values \textyen tan^{2} \textyen theta_{12} = 0.444^{+0.036}_{-0.030} and \textyen Delta m^{2}_{21} = 7.50^{+0.19}_{-0.20} \textyen times 10^{-5} ~ {\textyen rm eV}^{2}; a three-flavor analysis with \textyen theta_{13} as a free parameter yields the best-fit values \textyen tan^{2} \textyen theta_{12} = 0.452^{+0.035}_{-0.033}, \textyen Delta m^{2}_{21} = 7.50^{+0.19}_{-0.20} \textyen times 10^{-5} ~ {\textyen rm eV}^{2}, and \textyen sin^{2} \textyen theta_{13} = 0.020^{+0.016}_{-0.016}. This \textyen theta_{13} interval is consistent with other recent work combining the CHOOZ, atmospheric and long-baseline accelerator experiments. We also present a new global \textyen theta_{13} analysis, incorporating the CHOOZ, atmospheric and accelerator data, which indicates \textyen sin^{2} \textyen theta_{13} = 0.009^{+0.013}_{-0.007}. A nonzero value is suggested, but only at the 79\textyen% C.L.Comment: 10 pages, 7 figures. Version as published in PRD. The dChi2-map and prompt energy spectrum for this analysis are available at http://www.awa.tohoku.ac.jp/KamLAND/4th_result_data_release/4th_result_data_release.htm

    Marine Incursion: The Freshwater Herring of Lake Tanganyika Are the Product of a Marine Invasion into West Africa

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    The spectacular marine-like diversity of the endemic fauna of Lake Tanganyika, the oldest of the African Great Lakes, led early researchers to suggest that the lake must have once been connected to the ocean. Recent geophysical reconstructions clearly indicate that Lake Tanganyika formed by rifting in the African subcontinent and was never directly linked to the sea. Although the Lake has a high proportion of specialized endemics, the absence of close relatives outside Tanganyika has complicated phylogeographic reconstructions of the timing of lake colonization and intralacustrine diversification. The freshwater herring of Lake Tanganyika are members of a large group of pellonuline herring found in western and southern Africa, offering one of the best opportunities to trace the evolutionary history of members of Tanganyika's biota. Molecular phylogenetic reconstructions indicate that herring colonized West Africa 25–50MYA, at the end of a major marine incursion in the region. Pellonuline herring subsequently experienced an evolutionary radiation in West Africa, spreading across the continent and reaching East Africa's Lake Tanganyika during its early formation. While Lake Tanganyika has never been directly connected with the sea, the endemic freshwater herring of the lake are the descendents of an ancient marine incursion, a scenario which may also explain the origin of other Tanganyikan endemics

    Constraints on theta 13 from a three-flavor oscillation analysis of reactor antineutrinos at KamLAND

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    We present new constraints on the neutrino oscillation parameters Δm212, θ12, and θ13 from a three-flavor analysis of solar and KamLAND data. The KamLAND data set includes data acquired following a radiopurity upgrade and amounts to a total exposure of 3.49×1032 target-proton-year. Under the assumption of CPT invariance, a two-flavor analysis (θ13=0) of the KamLAND and solar data yields the best-fit values tan⁡2θ12=0.444-0.030+0.036 and Δm212=7.50-0.20+0.19×10-5 eV2; a three-flavor analysis with θ13 as a free parameter yields the best-fit values tan⁡2θ12=0.452-0.033+0.035, Δm212=7.50-0.20+0.19×10-5 eV2, and sin⁡2θ13=0.020-0.016+0.016. This θ13 interval is consistent with other recent work combining the CHOOZ, atmospheric and long-baseline accelerator experiments. We also present a new global θ13 analysis, incorporating the CHOOZ, atmospheric, and accelerator data, which indicates sin⁡2θ13=0.009-0.007+0.013. A nonzero value is suggested, but only at the 79% C.L

    SEARCH FOR EXTRATERRESTRIAL ANTINEUTRINO SOURCES WITH THE KamLAND DETECTOR

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    We present the results of a search for extraterrestrial electron antineutrinos ( 's) in the energy range 8.3 MeV < Eve < 31.8 MeV using the KamLAND detector. In an exposure of 4.53 kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting an upper limit on the probability of 8B solar ν e 's converting into Ve 's at 5.3 × 10-5 (90% CL), if we assume an undistorted Ve shape. This limit corresponds to a solar Ve flux of 93 cm-2 s-1 or an event rate of 1.6 events (kton - year)-1 above the energy threshold (Eve ≥8.3 MeV) . The present data also allows us to set more stringent limits on the diffuse supernova neutrino flux and on the annihilation rates for light dark matter particles

    A review of the systematic biology of fossil and living bony-tongue fishes, Osteoglossomorpha (Actinopterygii: Teleostei)

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    The bony-tongue fishes, Osteoglossomorpha, have been the focus of a great deal of morphological, systematic, and evolutionary study, due in part to their basal position among extant teleostean fishes. This group includes the mooneyes (Hiodontidae), knifefishes (Notopteridae), the abu (Gymnarchidae), elephantfishes (Mormyridae), arawanas and pirarucu (Osteoglossidae), and the African butterfly fish (Pantodontidae). This morphologically heterogeneous group also has a long and diverse fossil record, including taxa from all continents and both freshwater and marine deposits. The phylogenetic relationships among most extant osteoglossomorph families are widely agreed upon. However, there is still much to discover about the systematic biology of these fishes, particularly with regard to the phylogenetic affinities of several fossil taxa, within Mormyridae, and the position of Pantodon. In this paper we review the state of knowledge for osteoglossomorph fishes. We first provide an overview of the diversity of Osteoglossomorpha, and then discuss studies of the phylogeny of Osteoglossomorpha from both morphological and molecular perspectives, as well as biogeographic analyses of the group. Finally, we offer our perspectives on future needs for research on the systematic biology of Osteoglossomorpha

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