60 research outputs found

    Program Management for Sustainable University CubeSat Programs Based on the Experience of Five Generations of CubeSat Projects, BIRDS Program

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    BIRDS program is a university CubeSat program whose primary mission is capacity building of non-space faring countries. It has been run by Kyushu Institute of Technology, Japan, where a group of foreign and Japanese students designs, builds, tests and operates CubeSats. The program started in 2015. Roughly every year since 2017, BIRDS program delivered and launched multiple CubeSats from International Space Station. In total, the program generated 17 CubeSats in five generations. The satellites have been designed in a way so that even satellite beginners can go through the satellite system life cycles from the mission definition to the operation in two years, the duration of Master course. Subsequent generations of students overlap in the laboratory so that they can inherit the know-hows and the experience directly in-person. The satellite design has been modified based on the lessons learned in the former generations, especially during the operation phase. After going through the series of developments and operations, the satellite bus has become very mature. Currently, the initiative to open-source the BIRDS bus is also running. The program, rather than project, management aspects of university CubeSat program is discussed

    Inner Magnetospheric Response to the Interplanetary Magnetic Field By Component:Van Allen Probes and Arase Observations

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    We utilise 17 years of combined Van Allen Probes and Arase data to statistically analyse the response of the inner magnetosphere to the orientation of the IMF By component. Past studies have demonstrated that the IMF By component introduces a similarly oriented By component into the magnetosphere. However, these studies have tended to focus on field lines in the magnetotail only reaching as close to Earth as geosynchronous orbit. By exploiting data from these inner magnetospheric spacecraft, we have been able to investigate the response at radial distances of < 7 RE. When subtracting the background magnetic field values, provided by the T01 and IGRF magnetic field models, we find that the IMF By component does affect the configuration of the magnetic field lines in the inner magnetosphere. This control is observed throughout the inner magnetosphere, across both hemispheres, all radial distances, and all MLT sectors. The ratio of IMF By to observed By residual, also known as the "penetration efficiency", is found to be ~0.33. The IMF Bz component is found to increase, or inhibit, this control depending upon its orientation

    Efficacy and safety of alirocumab in patients with hypercholesterolemia not adequately controlled with non-statin lipid-lowering therapy or the lowest strength of statin : ODYSSEY NIPPON study design and rationale

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    Background: Statins are generally well-tolerated and serious side effects are infrequent, but some patients experience adverse events and reduce their statin dose or discontinue treatment altogether. Alirocumab is a highly specific, fully human monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9), which can produce substantial and sustained reductions of low-density lipoprotein cholesterol (LDL-C). Methods: The randomized, double-blind, placebo-controlled, parallel-group, phase 3 ODYSSEY NIPPON study will explore alirocumab 150 mg every 4 weeks (Q4W) in 163 Japanese patients with hypercholesterolemia who are on the lowest-strength dose of atorvastatin (5 mg/day) or are receiving a non-statin lipid-lowering therapy (LLT) (fenofibrate, bezafibrate, ezetimibe, or diet therapy alone). Hypercholesterolemia is defined as LDL-C ≥ 100 mg/dL (2.6 mmol/L) in patients with heterozygous familial hypercholesterolemia or non-familial hypercholesterolemia with a history of documented coronary heart disease, or ≥120 mg/dL (3.1 mmol/L) in patients with non-familial hypercholesterolemia classified as primary prevention category III (i.e. high-risk patients). During the 12-week double-blind treatment period, patients will be randomized (1:1:1) to receive alirocumab subcutaneously (SC) 150 mg Q4W alternating with placebo for alirocumab Q4W, or alirocumab 150 mg SC every 2 weeks (Q2W), or SC placebo Q2W. The primary efficacy endpoint is the percentage change in calculated LDL-C from baseline to week 12. The long-term safety and tolerability of alirocumab will also be investigated. Discussion: The ODYSSEY NIPPON study will provide insights into the efficacy and safety of alirocumab 150 mg Q4W or 150 mg Q2W among Japanese patients with hypercholesterolemia who are on the lowest-strength dose of atorvastatin, or are receiving a non-statin LLT (including diet therapy alone)

    Efficacy and safety of alirocumab 150 mg every 4 weeks in hypercholesterolemic patients on non-statin lipid-lowering therapy or lowest strength dose of statin : ODYSSEY NIPPON

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    Background: Alirocumab, a fully human monoclonal antibody to proprotein convertase subtilisin/kexin type 9, given every 2 weeks (Q2W), significantly reduced low-density lipoprotein cholesterol (LDL-C) levels in Japanese hypercholesterolemic patients on background statin. We evaluated alirocumab 150 mg every 4 weeks (Q4W) in patients on lowest-dose statin or non-statin lipid-lowering therapy (LLT). Methods: ODYSSEY NIPPON was a double-blind study conducted in Japanese patients with LDL-C≥100 mg/dL (heterozygous familial hypercholesterolemia or non-familial hypercholesterolemia with coronary heart disease) or ≥120 mg/dL (non-familial hypercholesterolemia, Japan Atherosclerosis Society category III) on atorvastatin 5 mg/day or non-statin LLT. Patients were randomized (1:1:1) to subcutaneous alirocumab 150 mg Q4W, alirocumab 150 mg Q2W, or placebo for the 12-week double-blind treatment period (DBTP), followed by a 52-week open-label treatment period (OLTP). At entry into the OLTP, patients received alirocumab 150 mg Q4W, with possible up-titration to 150 mg Q2W at Week 24. Results: Least-square mean percent change in LDL-C from baseline at Week 12 (primary efficacy endpoint) was -43.8% for alirocumab Q4W, -70.1% for Q2W, and -4.3% for placebo. During the OLTP, mean LDL-C change from baseline was -45.1% at Week 20, with a further reduction at Week 36, with achieved levels maintained to Week 64. Percent of patients with≥1 adverse event (DBTP) was 51.9% with alirocumab Q4W, 47.2% with Q2W, and 46.4% with placebo. Most common adverse events were infections and infestations (25.9%, 22.6%, 17.9%, respectively), gastrointestinal disorders (13.0%, 9.4%, 12.5%), nervous system disorders (5.6%, 7.5%, 10.7%), and general disorders and administration-site conditions (3.7%, 11.3%, 5.4%). Conclusions: Hypercholesterolemic Japanese patients who tolerate only lowest-strength dose statin or non-statin LLT can achieve robust LDL-C reduction with alirocumab 150 mg Q4W, in addition to their current LLT. Alirocumab 150 mg Q4W dosing was efficacious and generally well tolerated without new safety concerns

    Giant Pulsations Excited by a Steep Earthward Gradient of Proton Phase Space Density: Arase Observation

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    AbstractWe present observational evidence of drift resonance between westward propagating odd mode standing ultralow frequency waves and energetic protons. Compressional ∼13 mHz (Pc4 band) waves and proton flux oscillations at >50 keV were detected at ∼03 hr magnetic local time by the Arase satellite on 15 April 2017. The azimuthal wave number (m number) is estimated to be ∼−50 from ground observations, while the theory of drift resonance gives m ∼− 49 for odd mode waves and ∼110‐keV protons, providing evidence that the drift resonance indeed took place in this event. We also found a steep earthward gradient of proton phase space density, which can quantitatively explain the wave excitation. The observed waves show typical features of giant pulsations (Pgs), regarding local time, m number, and flux oscillations. This study, therefore, has great implications to the field line mode structure and excitation mechanism of Pgs

    Dynamics of Sub-Auroral Polarization Streams observed by the SuperDARN Hokkaido radar during large geomagnetic storms

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    第3回極域科学シンポジウム/第36回極域宙空圏シンポジウム 11月27日(火) 国立極地研究所 2階大会議

    Active auroral arc powered by accelerated electrons from very high altitudes

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    オーロラ粒子の加速領域が超高高度まで広がっていたことを解明 -オーロラ粒子の加速の定説を覆す発見-. 京都大学プレスリリース. 2021-01-20.Bright, discrete, thin auroral arcs are a typical form of auroras in nightside polar regions. Their light is produced by magnetospheric electrons, accelerated downward to obtain energies of several kilo electron volts by a quasi-static electric field. These electrons collide with and excite thermosphere atoms to higher energy states at altitude of ~ 100 km; relaxation from these states produces the auroral light. The electric potential accelerating the aurora-producing electrons has been reported to lie immediately above the ionosphere, at a few altitudes of thousand kilometres1. However, the highest altitude at which the precipitating electron is accelerated by the parallel potential drop is still unclear. Here, we show that active auroral arcs are powered by electrons accelerated at altitudes reaching greater than 30, 000 km. We employ high-angular resolution electron observations achieved by the Arase satellite in the magnetosphere and optical observations of the aurora from a ground-based all-sky imager. Our observations of electron properties and dynamics resemble those of electron potential acceleration reported from low-altitude satellites except that the acceleration region is much higher than previously assumed. This shows that the dominant auroral acceleration region can extend far above a few thousand kilometres, well within the magnetospheric plasma proper, suggesting formation of the acceleration region by some unknown magnetospheric mechanisms
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