864 research outputs found

    Morphological study of penumbral formation

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    Penumbrae are known to be area of mainly horizontal magnetic field surrounding umbrae of relatively large and mature sunspots. In this paper, we observationally studied the formation of penumbrae in NOAA10978, where several penumbral formations were observed in G-band images of SOT/Hinode. Thanks to the continuous observation by Hinode, we could morphologically follow the evolution of sunspots and found that there are several paths to the penumbral formation: (1) Active accumulation of magnetic flux, (2) Rapid emergence of magnetic field, and (3) Appearance of twisted or rotating magnetic tubes. In all of these cases, magnetic fields are expected to sustain high inclination at the edges of flux tube concentration longer than the characteristic growth time of downward magnetic pumping.Comment: accepted for publication in PAS

    Observations of Plasma Blob Ejection from a Quiescent Prominence by Hinode SOT

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    We report findings from 0.2" resolution observations of the 2007 October 03 quiescent prominence observed with the Solar Optical Telescope on the Hinode satellite. The observations show clear ejections from the top of the quiescent prominence of plasma blobs. The ejections, originating from the top of rising prominence threads, are impulsively accelerated to Alfvenic velocities and then undergo ballistic motion. The ejections have a characteristic size between ~ 1000 - 2000 km. These characteristics are similar to downwardly propagating knots (typical size ~ 700 km) that have been observed in prominence threads, we suggest that the plasma blob ejections could be the upward moving counterpart to the downwardly propagating knots. We discuss the tearing instability as a possible mechanism to explain the ejections.Comment: 9 Pages, 4 Figures, Accepted for publication in PASJ letter

    Magnetic Structure of Umbral Dots Observed with Hinode Solar Optical Telescope

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    High resolution and seeing-free spectroscopic observation of a decaying sunspot was done with the Solar Optical Telescope aboard Hinode satellite. The target was NOAA 10944 located in the west side of the solar surface from March 2 to March 4, 2007. The umbra included many umbral dots (UDs) with size of ~300 km in continuum light. We report the magnetic structures and Doppler velocity fields around UDs, based on the Milne-Eddington inversion of the two iron absorption lines at 6302 angstrom. The histograms of magnetic field strength(B), inclination angle(i), and Doppler velocity(v) of UDs showed a center-to-limb variation. Observed at disk center, UDs had (1)slightly smaller field strength (Delta B=-17 Gauss) and (2)relative blue shifts (Delta v=28 m s-1) compared to their surroundings. When the sunspot got close to the limb, UDs and their surroundings showed almost no difference in the magnetic and Doppler values. This center-to-limb variation can be understood by the formation height difference in a cusp-shaped magnetized atmosphere around UDs, due to the weakly magnetized hot gas intrusion. In addition, some UDs showed oscillatory light curves with multiple peaks around 10 min, which may indicate the presence of the oscillatory convection. We discuss our results in the frameworks of two theoretical models, the monolithic model (Schussler & Vogler 2006) and the field-free intrusion model (Spruit & Scharmer 2006).Comment: 8 pages, 8 figures, accepted for publication in PAS

    Strategies for Prevention of Neural Tube Defects

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    Folic and Folate Acid

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    Folate is a water-soluble B vitamin, also known as vitamin B9 or folacin. It is found naturally in a wide variety of foods, including vegetables, fruits, nuts, beans, dairy products, meats, eggs, seafood, and grains. However, only about 50% of the folate naturally present in food is bioavailable. Folate is critical in the metabolism of nucleic acid precursors and several amino acids, as well as in methylation reactions. Folic acid helps our bodies produce and maintain new cells, and it helps prevent DNA changes that may lead to cancer. Folate deficiency can cause anemia, insomnia, irritability, depression, Alzheimer’s disease, cardiovascular disease, and more serious health problems. An inadequate folate status during early pregnancy increases the risk of congenital anomalies, such as neural tube defects (NTDs), which are life-threatening and cause life-long disabilities. Therefore, it has been recommended by the U.S. Public Health Service that even before becoming pregnant, women should consume 400 µg of synthetic folic acid daily, whether in the form of foods or supplements, as well as maintain a healthy diet of folate-rich foods to reduce NTD risk

    Optical signature of Weyl electronic structures in tantalum pnictides TaPnPn (Pn=Pn= P, As)

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    To investigate the electronic structure of Weyl semimetals TaPnPn (Pn=Pn=P, As), optical conductivity [σ(ω)\sigma(\omega)] spectra are measured over a wide range of photon energies and temperatures, and these measured values are compared with band calculations. Two significant structures can be observed: a bending structure at ω\hbar\omega\sim85 meV in TaAs, and peaks at ω\hbar\omega\sim 50 meV (TaP) and \sim30 meV (TaAs). The bending structure can be explained by the interband transition between saddle points connecting a set of W2W_2 Weyl points. The temperature dependence of the peak intensity can be fitted by assuming the interband transition between saddle points connecting a set of W1W_1 Weyl points. Owing to the different temperature dependence of the Drude weight in both materials, it is found that the Weyl points of TaAs are located near the Fermi level, whereas those of TaP are further away.Comment: 8 pages, 6 figure

    Improved Insulin Resistance and Glucose Variability by Super-Low Carbohydrate Diet

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    Background Diabetes mellitus (DM) has been more prevalent. American Diabetes Association (ADA) proposed the Standards of Medical Care in Diabetes-2022. For nutritional therapy, low carbohydrate diet (LCD) has been recognized for its benefits. Authors have continued diabetic research concerning LCD and meal tolerance test (MTT). Case Presentation The case is 61-year-old male with type 2 diabetes mellitus (T2DM) for years. His hemoglobin A1c (HbA1c) increased to 7.8% in autumn 2021, and further evaluation and treatment was conducted including LCD, daily check of meal and carbohydrate amount, 75 g OGTT, glucagon stimulation test (GST) and others. Results He was on super-LCD method including 12% of carbohydrate. His carbohydrate intake amount and 45-minutes post-prandial blood glucose showed significant correlation. The results of 75 g OGTT twice in May 2020 and December 2021 showed that similar pattern of glucose and insulin responses and insulinogenic index (IGI). In contrast, they showed decreased fasting immuno-reactive insulin (IRI) and Homeostasis model assessment insulin resistance (HOMA-R). For GST, C-peptide showed normal response. Discussion and Conclusion Judging from the results of MTT, OGTT, GST and IGI, he seems to show rather decreased insulin resistance by LCD associated with preserved insulin secretion ability to some degree. Further investigation would be required from pathophysiological point of view
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