74 research outputs found

    Probing Early Cosmic Magnetic Fields through Pair Echos from High-Redshift GRBs

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    We discuss the expected properties of pair echo emission from gamma-ray bursts (GRBs) at high redshifts (z5z \gtrsim 5), their detectability, and the consequent implications for probing intergalactic magnetic fields (IGMFs) at early epochs. Pair echos comprise inverse Compton emission by secondary electron-positron pairs produced via interactions between primary gamma-rays from the GRB and low-energy photons of the diffuse intergalactic radiation, arriving with a time delay that depends on the nature of the intervening IGMFs. At sufficiently high zz, the IGMFs are unlikely to have been significantly contaminated by astrophysical outflows, and the relevant intergalactic radiation may be dominated by the well-understood cosmic microwave background (CMB). Pair echoes from luminous GRBs at z510z \sim 5-10 may be detectable by future facilities such as the Cherenkov Telescope Array or the Advanced Gamma-ray Imaging System, as long as the GRB primary emission extends to multi-TeV energies, the comoving IGMFs at these redshifts are B10161015 GaussB \sim 10^{-16}-10^{-15}~{\rm Gauss}, and the non-CMB component of the diffuse intergalactic radiation is relatively low. Observations of pair echos from high-zz GRBs can provide a unique, in-situ probe of weak IGMFs during the epochs of early structure formation and cosmic reionization.Comment: 22 pages, 7 figure

    Shear Power Spectrum Reconstruction using Pseudo-Spectrum Method

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    We develop a pseudo power spectrum technique for measuring the lensing power spectrum from weak lensing surveys in both the full sky and flat sky limits. The power spectrum approaches have a number of advantages over the traditional correlation function approach. We test the pseudo spectrum method by using numerical simulations with square-shape boundary that include masked regions with complex configuration due to bright stars and saturated spikes. Even when 25% of total area of the survey is masked, the method recovers the E-mode power spectrum at a sub-percent precision over a wide range of multipoles 100<l<10000. The systematic error is smaller than the statistical errors expected for a 2000 square degree survey. The residual B-mode spectrum is well suppressed in the amplitudes at less than a percent level relative to the E-mode. We also find that the correlated errors of binned power spectra caused by the survey geometry effects are not significant. Our method is applicable to the current and upcoming wide-field lensing surveys.Comment: 11 pages, 4 figures, accepted for publication in MNRA

    Association between upper limb movements during drumming and cognition in older adults with cognitive impairment and dementia at a nursing home: a pilot study

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    BackgroundDespite the association between motor dysfunction and dementia, quantitative assessment of dementia-related specific motor dysfunction in patients with severe dementia is difficult. Thus, this study aimed to develop a new method to measure upper limb motor function in people with dementia.MethodsWe examined the relationship between dementia severity and dementia-related specific motor dysfunction using the Mini-Mental State Examination (MMSE), a dementia screening test. Participants comprised 16 nursing home residents with a mean age of 86 years and MMSE score of 15.75 (range, 1–27) Points. Participants were seated in a circle and instructed to play a drum that was placed in their lap using mallets (drumsticks) in their dominant hand. Acceleration and gyroscopic sensors were attached to their wrists to collect data on arm movements while drumming. Upper limb motor characteristics were confirmed by recording acceleration and arm movement during drumming and analyzing the correlation with handgrip strength.ResultsHandgrip strength was correlated with arm elevation angle during drumming. The arm elevation angle displayed a significant regression equation with the MMSE score and showed the best regression equation along with handgrip strength (adjusted R2 = 0.6035, p = 0.0009).ConclusionWe developed a new method using drums to measure upper limb motor function in people with dementia. We also verified that the average arm elevation angle during drumming could predict cognitive dysfunction. This system may be used to monitor people with dementia in a simple and safe way

    Neuroprotective Efficacy of YM872, an ␣-Amino-3-Hydroxy-5- Methylisoxazole-4-Propionic Acid Receptor Antagonist, after Permanent Middle Cerebral Artery Occlusion in Rats

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    ABSTRACT The neuroprotective efficacy of YM872, a novel, highly watersoluble ␣-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antagonist, was investigated in rats subjected to permanent occlusion of the left middle cerebral artery. The rats were assessed either histologically or neurologically 24 hr or 1 wk after ischemia. YM872 was intravenously infused for either 4 or 24 hr at dose rates of 0 to 20 mg/kg/hr starting 5 min after ischemia to examine the effect of prolonged treatment. YM872 was then infused at 20 mg/kg/hr beginning 0 to 4 hr after ischemia to determine the efficacy time window. Additionally, a 20 mg/kg/hr dose rate of YM872 was infused for 4 hr in single day-or 5-day repetitive-administrations to evaluate long-term benefits of the drug. YM872 significantly reduced infarct volume in both 4-and 24-hr treatment groups measured 24 hr after ischemia. No difference was observed in the degree of protection between length of infusion. Significant neuroprotection was maintained even when drug administration was delayed up to 2 hr after ischemia. A single YM872-administration significantly improved neurological deficit and reduced infarct volume (30%, P Ͻ .01) measured 1 wk after ischemia. YM872 treatment did not induce such adverse effects as physiological changes, serious behavioral abnormalities or nephrotoxicity. These data suggest that the ␣-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor plays a crucial role in the progression of neuronal damage in the early phase of ischemia and that YM872 may be useful in treating acute ischemic stroke

    The Japanese space gravitational wave antenna; DECIGO

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    DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. DECIGO is expected to open a new window of observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing various mysteries of the universe such as dark energy, formation mechanism of supermassive black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of three drag-free spacecraft, whose relative displacements are measured by a differential Fabry– Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre- DECIGO first and finally DECIGO in 2024

    DECIGO pathfinder

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    DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected to provide us fruitful insights into the universe, in particular about dark energy, a formation mechanism of supermassive black holes, and the inflation of the universe. Since DECIGO will be an extremely large mission which will formed by three drag-free spacecraft with 1000m separation, it is significant to gain the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. The conceptual design and current status of the first milestone mission, DPF, are reviewed in this article

    Geochemistry and geochronology of the Antananarivo and the Masora domain, eastern Madagascar

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    第2回極域科学シンポジウム/第31回極域地学シンポジウム 11月17日(木) 国立極地研究所 2階大会議

    Randomized phase II study of pemetrexed or pemetrexed plus bevacizumab for elderly patients with previously untreated non-squamous non-small cell lung cancer: Results of the Lung Oncology Group in Kyushu (LOGIK1201)

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    Objectives: To evaluate the efficacy and safety, we conducted a randomized phase II study of pemetrexed (Pem) versus Pem + bevacizumab (Bev) for elderly patients with non-squamous non-small cell lung cancer (NSqNSCLC). Patients and methods: The eligibility criteria were as follows: NSqNSCLC, no prior therapy,stage IIIB/IV disease or postoperative recurrence, age: ?75 years, performance status (PS): 0?1, and adequate bone marrow function. The patients were randomly assigned (1:1 ratio)to receive Pem or Pem + Bev. The primary endpoint was progression-free survival (PFS).The secondary endpoints were the response rate, OS, toxicities, and cost-effectiveness. Results: Forty-one patients were enrolled and 40 (20 from each group) were assessable. Their characteristics were as follows: male/female = 23/17; median age (range) = 78 (75?83); stage IIIB/IV/postoperative recurrence = 1/30/9; PS 0/1 = 11/29. All cases involved adenocarcinoma.There was no significant intergroup difference in PFS and the median PFS (95% confidence interval) values of the Pem and Pem + Bev groups were 5.4 (3.0?7.4) and 5.5 (3.6?9.9) months, respectively (p = 0.66). The response rate was significantly higher in the Pem + Bev group(15% vs. 55%, p = 0.0146), and there was no significant difference in OS (median: 16.0 vs. 16.4 months, p = 0.58). Grade 3 and 4 leukopenia, neutropenia,and thrombocytopenia were seen in 10 and 30, 20 and 55, and 5 and 5 cases, respectively. Drug costs were higher in the Pem + Bev group (median: 1,522,008 vs. 3,368,428 JPY, p = 0.01). No treatment-related deaths occurred. Conclusions: Adding Bev to Pem did not result in improved survival in the elderly NSqNSCLC patients. Compared with Pem + Bev, Pem monotherapy had similar effects on survival, a more favorable toxicity profile, and was more cost-effective in elderly NSqNSCLC patients. Pem monotherapy might be one of the optional regimen for NSqNSCLC patients aged ?75 years
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