Solar Radio Bursts with Spectral Fine Structures in Preflares

A good observation of preflare activities is important for us to understand the origin and triggering mechanism of solar flares, and to predict the occurrence of solar flares. This work presents the characteristics of microwave spectral fine structures as preflare activities of four solar flares observed by Ond\v{r}ejov radio spectrograph in the frequency range of 0.8--2.0 GHz. We found that these microwave bursts which occurred 1--4 minutes before the onset of flares have spectral fine structures with relatively weak intensities and very short timescales. They include microwave quasi-periodic pulsations (QPP) with very short period of 0.1-0.3 s and dot bursts with millisecond timescales and narrow frequency bandwidths. Accompanying these microwave bursts, there are filament motions, plasma ejection or loop brightening on the EUV imaging observations and non-thermal hard X-ray emission enhancements observed by RHESSI. These facts may reveal certain independent non-thermal energy releasing processes and particle acceleration before the onset of solar flares. They may be conducive to understand the nature of solar flares and predict their occurrence

Diagnosing the Source Region of a Solar Burst on 26 September 2011 by Microwave Type III Pairs

This work reports a peculiar and interesting train of microwave type III pair bursts in the impulsive rising phase of a solar flare on 2011 September 26. The observations include radio spectrometers at frequency of 0.80 - 2.00 GHz, hard X-ray (RHESSI and FERMI), EUV images of SWAP/PROBA-2 and magnetogram of HMI/SDO. By using a recently developed method (Tan et al. 2016a), we diagnosed the plasma density, temperature, plasma beta, magnetic field near the source region, the energy of energetic electrons and the distance between the acceleration region and the emission start sites of type III bursts. From the diagnostics, we find that: (1) The plasma density, temperature, magnetic field, and the distance between the acceleration region and the emission start sites almost have no obvious variations during the period of type III pair trains, while the energy of electrons has an obvious peak value which is consistent to the hard X-ray emission. (2) The plasma beta is much higher than an unity showing a highly dynamic process near the emission start site of type III bursts. (3) Although the reversed-slope type III branches drift slower at one order of magnitude than that of the normal type III branches, the related downgoing and upgoing electrons still could have same order of magnitude of energy. These facts indicate that both of the upgoing and downgoing electrons are possibly accelerated by similar mechanism and in a small source region. This diagnostics can help us to understand the microphysics in the source region of solar bursts.Comment: 14 pages, 5 figures, accepted by Solar Physic

Heritage house maintenance using 3D city model application domain extension approach

Heritage house is part of the architectural heritage of Malaysia that highly valued. Many efforts by the Department of Heritage to preserve this heritage house such as monitoring the damage problems of heritage house. The damage problems of heritage house might be caused by wooden decay, roof leakage and exfoliation of wall. One of the initiatives for maintaining and documenting this heritage house is through Three-dimensional (3D) of technology. 3D city models are widely used now and much used by researchers for management and analysis. CityGML is a standard tool that usually used by researchers to exchange, storing and managing virtual 3D city models either geometric and semantic information. Moreover, it also represent multi-scale of 3D model in five level of details (LoDs) whereby each of level give a distinctive functions. The extension of CityGML was recently introduced and can be used for problems monitoring and the number of habitants of a house

{2-[(2-Carbamothiol­ylhydrazin-1-yl­idene-κ2 N 1,S)meth­yl]-6-hy­droxy­phenolato-κO 1}(triphenyl­phosphine-κP)nickel(II) chloride

The deprotonated Schiff base ligand in the title compound, [Ni(C8H8N3O2S)(C18H15P)]Cl, functions as an N,O,S-chelating anion to the phosphine-coordinated Ni atom, which exists in a distorted square-planar geometry. The hy­droxy group forms an intra­molecular O—H⋯O hydrogen bond. The two amino groups of the cation are hydrogen-bond donors to the chloride anion; the hydrogen bonds generate a chain structure running along the b axis

Nuclear proteome response to cell wall removal in rice (Oryza sativa)

Plant cells are routinely exposed to various pathogens and environmental stresses that cause cell wall perturbations. Little is known of the mechanisms that plant cells use to sense these disturbances and transduce corresponding signals to regulate cellular responses to maintain cell wall integrity. Previous studies in rice have shown that removal of the cell wall leads to substantial chromatin reorganization and histone modification changes concomitant with cell wall re-synthesis. But the genes and proteins that regulate these cellular responses are still largely unknown. Here we present an examination of the nuclear proteome differential expression in response to removal of the cell wall in rice suspension cells using multiple nuclear proteome extraction methods. A total of 382 nuclear proteins were identified with two or more peptides, including 26 transcription factors. Upon removal of the cell wall, 142 nuclear proteins were up regulated and 112 were down regulated. The differentially expressed proteins included transcription factors, histones, histone domain containing proteins, and histone modification enzymes. Gene ontology analysis of the differentially expressed proteins indicates that chromatin & nucleosome assembly, protein-DNA complex assembly, and DNA packaging are tightly associated with cell wall removal. Our results indicate that removal of the cell wall imposes a tremendous challenge to the cells. Consequently, plant cells respond to the removal of the cell wall in the nucleus at every level of the regulatory hierarchy.This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at [email protected]

1-(2,3,4-Trihydroxy­benzyl­idene)thio­semicarbazide

In the title mol­ecule, C8H9N3O3S, the thio­semicarbazide =N—NH—C(=S)—NH— fragment is twist a different degree of twist in the three independent mol­ecules [dihedral angles = 7.6 (1), 11.6 (1) and 20.7 (1)°]. Intra­molecular O—H⋯N and O—H⋯O hydrogen bonds occur. In the crystal, the hydr­oxy and amino groups are hydrogen-bond donors and the O—H⋯O, O—H⋯S and N—H⋯O hydrogen bonds generate a layer motif

1-(2,3,4-Trihydroxy­benzyl­idene)-4-ethyl­thio­semicarbazide

In the title mol­ecule, C10H13N3O3S, the thio­semicarbazide =N—NH—C(=S)—NH– fragment is twisted with respect to the aromatic ring [dihedral angle = 20.5 (1)°]. A weak N—H⋯S hydrogen bond [3.480 (1) Å] links two mol­ecules about a center of inversion to generate a ring. The hydr­oxy groups are engaged in inter­molecular hydrogen bonding; the O—H⋯O and O—H⋯S hydrogen bonds generate a layer motif