241 research outputs found

    A Study of the Low Energy Octupole Resonance

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    開始ページ、終了ページ: 冊子体のページ付

    Quality-controlled meteorological datasets from SIGMA automatic weather stations in northwest Greenland, 2012–2020

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    In situ meteorological data are essential to better understand ongoing environmental changes in the Arctic. Here, we present a dataset of quality-controlled meteorological observations from two automatic weather stations in northwest Greenland from July 2012 to the end of August 2020. The stations were installed in the accumulation area on the Greenland Ice Sheet (SIGMA-A site, 1490 m a.s.l.) and near the equilibrium line of the Qaanaaq Ice Cap (SIGMA-B site, 944 m a.s.l.). We describe the two-step sequence of quality-controlling procedures that we used to create increasingly reliable datasets by masking erroneous data records. Those datasets are archived in the Arctic Data archive System (ADS) (SIGMA-A – https://doi.org/10.17592/001.2022041303, Nishimura et al., 2023f; SIGMA-B – https://doi.org/10.17592/001.2022041306, Nishimura et al., 2023c). We analyzed the resulting 2012–2020 time series of air temperature, surface height, and surface albedo and histograms of longwave radiation (a proxy of cloudiness). We found that surface height increased, and no significant albedo decline in summer was observed at the SIGMA-A site. In contrast, high air temperatures and frequent clear-sky conditions in the summers of 2015, 2019, and 2020 at the SIGMA-B site caused significant albedo and surface lowering. Therefore, it appears that these weather condition differences led to the apparent surface height decrease at the SIGMA-B site but not at the SIGMA-A site. We anticipate that this quality-controlling method and these datasets will aid in climate studies of northwest Greenland and will contribute to the advancement of broader polar climate studies.</p

    A long gamma-ray burst from a merger of compact objects

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    Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions. Bursts of long (>2 s) duration are produced by the core-collapse of massive stars, those of short (< 2 s) duration by the merger of two neutron stars (NSs). A third class of events with hybrid high-energy properties was identified, but never conclusively linked to a stellar progenitor. The lack of bright supernovae rules out typical core-collapse explosions, but their distance scales prevent sensitive searches for direct signatures of a progenitor system. Only tentative evidence for a kilonova has been presented. Here we report observations of the exceptionally bright GRB211211A that classify it as a hybrid event and constrain its distance scale to only 346 Mpc. Our measurements indicate that its lower-energy (from ultraviolet to near-infrared) counterpart is powered by a luminous (~1E42 erg/s) kilonova possibly formed in the ejecta of a compact binary merger.Comment: original version, accepted for publication after revisio

    Heart Failure-Inducible Gene Therapy Targeting Protein Phosphatase 1 Prevents Progressive Left Ventricular Remodeling

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    BACKGROUND: The targeting of Ca(2+) cycling has emerged as a potential therapy for the treatment of severe heart failure. These approaches include gene therapy directed at overexpressing sarcoplasmic reticulum (SR) Ca(2+) ATPase, or ablation of phospholamban (PLN) and associated protein phosphatase 1 (PP1) protein complexes. We previously reported that PP1β, one of the PP1 catalytic subunits, predominantly suppresses Ca(2+) uptake in the SR among the three PP1 isoforms, thereby contributing to Ca(2+) downregulation in failing hearts. In the present study, we investigated whether heart-failure-inducible PP1β-inhibition by adeno-associated viral-9 (AAV9) vector mediated gene therapy is beneficial for preventing disease progression in genetic cardiomyopathic mice. METHODS: We created an adeno-associated virus 9 (AAV9) vector encoding PP1β short-hairpin RNA (shRNA) or negative control (NC) shRNA. A heart failure inducible gene expression system was employed using the B-type natriuretic protein (BNP) promoter conjugated to emerald-green fluorescence protein (EmGFP) and the shRNA sequence. AAV9 vectors (AAV9-BNP-EmGFP-PP1βshRNA and AAV9-BNP-EmGFP-NCshRNA) were injected into the tail vein (2×10(11) GC/mouse) of muscle LIM protein deficient mice (MLPKO), followed by serial analysis of echocardiography, hemodynamic measurement, biochemical and histological analysis at 3 months. RESULTS: In the MLPKO mice, BNP promoter activity was shown to be increased by detecting both EmGFP expression and the induced reduction of PP1β by 25% in the myocardium. Inducible PP1βshRNA delivery preferentially ameliorated left ventricular diastolic function and mitigated adverse ventricular remodeling. PLN phosphorylation was significantly augmented in the AAV9-BNP-EmGFP-PP1βshRNA injected hearts compared with the AAV9-BNP-EmGFP-NCshRNA group. Furthermore, BNP production was reduced, and cardiac interstitial fibrosis was abrogated at 3 months. CONCLUSION: Heart failure-inducible molecular targeting of PP1β has potential as a novel therapeutic strategy for heart failure
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