Spectroscopic Studies of Limb Spicules. I. Radial and Turbulent Velocities

We made high-resolution spectroscopic observations of limb-spicules in H-alpha using the Vertical Spectrograph of Domeless Solar Telescope at Hida Observatory. While more than half of the observed spicules have Gaussian line-profiles, some spicules have distinctly asymmetric profiles which can be fitted with two Gaussian components. The faster of these components has radial velocities of 10 - 40 km/s and Doppler-widths of about 0.4 A which suggest that it is from a single spicule oriented nearly along the line-of-sight. Profiles of the slower components and the single-Gaussian type show very similar characteristics. Their radial velocities are less than 10 km/s and the Doppler-widths are 0.6 - 0.9 A. Non-thermal "macroturbulent" velocities of order 30 km/s are required to explain these width-values.Comment: 13 pages, 12 figures, to be published in Publications of the Astronomical Society of Japa

Investigation of the Long-term Variation of Solar Ca II K Intensity. II. Reconstruction of Solar UV Irradiance

Reconstruction of long-term solar UV variations during the entire 20th century is reported. The sunspot number has been used for this purpose so far. By using the full-disk Ca K intensity as an additional solar UV proxy, the range of allowed values for the reconstructed UV irradiance becomes more restricted. We use long-term archival data of the photographic Ca K plates digitized at the Kodaikanal Solar Observatory. The photographic calibration method developed in our previous paper (Paper I) is applied. Various long-term proxy data of solar activity have been used to estimate past UV irradiance. In light of this context, some issues using the historical Ca K data are commented on

Observations of Chromospheric Anemone Jets with Hinode SOT and Hida Ca II Spectroheliogram

We present the first simultaneous observations of chromospheric "anemone" jets in solar active regions with Hinode SOT Ca II H broadband filetergram and Ca II K spetroheliogram on the Domeless Solar Telescope (DST) at Hida Observatory. During the coordinated observation, 9 chromospheric anemone jets were simultaneously observed with the two instruments. These observations revealed three important features, i.e.: (1) the jets are generated in the lower chromosphere, (2) the length and lifetime of the jets are 0.4-5 Mm and 40-320 sec, (3) the apparent velocity of the jets with Hinode SOT are 3-24 km/s, while Ca II K3 component at the jets show blueshifts (in 5 events) in the range of 2- 6 km/s. The chromospheric anemone jets are associated with mixed polarity regions which are either small emerging flux regions or moving magnetic features. It is found that the Ca II K line often show red or blue asymmetry in K2/K1 component: the footpoint of the jets associated with emerging flux regions often show redshift (2-16 km/s), while the one with moving magnetic features show blueshift (around 5 km/s). Detailed analysis of magnetic evolution of the jet foaming regions revealed that the reconnection rate (or canceling rate) of the total magnetic flux at the footpoint of the jets are of order of 10^{16} Mx/s, and the resulting magnetic energy release rate (1.1-10) x 10^{24} erg/s, with the total energy release (1-13) x 10^{26} erg for the duration of the magnetic cancellations, 130s. These are comparable to the estimated total energy, 10^{26} erg, in a single chromospheric anemone jet. An observation-based physical model of the jet is presented. The relation between chromospheric anemone jets and Ellerman bombs is discussed.Comment: 22 pages, 27 figures, accepted for Publications of the Astronomical Society of Japa

Simulation-based model checking approach to cell fate specification during Caenorhabditis elegans vulval development by hybrid functional Petri net with extension

<p>Abstract</p> <p>Background</p> <p>Model checking approaches were applied to biological pathway validations around 2003. Recently, Fisher <it>et al</it>. have proved the importance of model checking approach by inferring new regulation of signaling crosstalk in <it>C. elegans </it>and confirming the regulation with biological experiments. They took a discrete and state-based approach to explore all possible states of the system underlying vulval precursor cell (VPC) fate specification for desired properties. However, since both discrete and continuous features appear to be an indispensable part of biological processes, it is more appropriate to use quantitative models to capture the dynamics of biological systems. Our key motivation of this paper is to establish a quantitative methodology to model and analyze <it>in silico </it>models incorporating the use of model checking approach.</p> <p>Results</p> <p>A novel method of modeling and simulating biological systems with the use of model checking approach is proposed based on hybrid functional Petri net with extension (HFPNe) as the framework dealing with both discrete and continuous events. Firstly, we construct a quantitative VPC fate model with 1761 components by using HFPNe. Secondly, we employ two major biological fate determination rules – Rule I and Rule II – to VPC fate model. We then conduct 10,000 simulations for each of 48 sets of different genotypes, investigate variations of cell fate patterns under each genotype, and validate the two rules by comparing three simulation targets consisting of fate patterns obtained from <it>in silico </it>and <it>in vivo </it>experiments. In particular, an evaluation was successfully done by using our VPC fate model to investigate one target derived from biological experiments involving hybrid lineage observations. However, the understandings of hybrid lineages are hard to make on a discrete model because the hybrid lineage occurs when the system comes close to certain thresholds as discussed by Sternberg and Horvitz in 1986. Our simulation results suggest that: Rule I that cannot be applied with qualitative based model checking, is more reasonable than Rule II owing to the high coverage of predicted fate patterns (except for the genotype of <it>lin-15ko; lin-12ko </it>double mutants). More insights are also suggested.</p> <p>Conclusion</p> <p>The quantitative simulation-based model checking approach is a useful means to provide us valuable biological insights and better understandings of biological systems and observation data that may be hard to capture with the qualitative one.</p