A Circular-ribbon Solar Flare Following an Asymmetric Filament Eruption

The dynamic properties of flare ribbons and the often associated filament eruptions can provide crucial information on the flaring coronal magnetic field. This Letter analyzes the GOES-class X1.0 flare on 2014 March 29 (SOL2014-03-29T17:48), in which we found an asymmetric eruption of a sigmoidal filament and an ensuing circular flare ribbon. Initially both EUV images and a preflare nonlinear force-free field model show that the filament is embedded in magnetic fields with a fan-spine-like structure. In the first phase, which is defined by a weak but still increasing X-ray emission, the western portion of the sigmoidal filament arches upward and then remains quasi-static for about five minutes. The western fan-like and the outer spine-like fields display an ascending motion, and several associated ribbons begin to brighten. Also found is a bright EUV flow that streams down along the eastern fan-like field. In the second phase that includes the main peak of hard X-ray (HXR) emission, the filament erupts, leaving behind two major HXR sources formed around its central dip portion and a circular ribbon brightened sequentially. The expanding western fan-like field interacts intensively with the outer spine-like field, as clearly seen in running difference EUV images. We discuss these observations in favor of a scenario where the asymmetric eruption of the sigmoidal filament is initiated due to an MHD instability and further facilitated by reconnection at a quasi-null in corona; the latter is in turn enhanced by the filament eruption and subsequently produces the circular flare ribbon.Comment: 7 pages, 5 figures, accepted to ApJ Letter

H3PW12O40/SBA-15 for the Solventless Synthesis of 3-Substituted Indoles

A family of silica-supported H3PW12O40 (HPW) solid acid catalysts was prepared by wet impregnation of mesoporous SBA-15 and investigated for the solventless synthesis of 3-substituted indoles under mild conditions. Mesoporous SBA-15 facilitated a high dispersion of immobilised H3PW12O40, significantly improving the catalytic efficiency of the heteropolyacid for the desired multi-component transformation. The yield of 3-substituted indoles strongly correlated with HPW loading (which spanned 3.2–51.6 wt %) and corresponding acid strength; the 51.6 wt % HPW/SBA-15 delivered 81% yield of 2-[(1H-indol-3-yl)(phenyl)methyl]malononitrile, approximately five times greater than that of the unsupported HPW, and exhibited a broad substrate scope for aromatic aldehydes

Incorporating interactive 3-dimensional graphics in astronomy research papers

Most research data collections created or used by astronomers are intrinsically multi-dimensional. In contrast, all visual representations of data presented within research papers are exclusively 2-dimensional. We present a resolution of this dichotomy that uses a novel technique for embedding 3-dimensional (3-d) visualisations of astronomy data sets in electronic-format research papers. Our technique uses the latest Adobe Portable Document Format extensions together with a new version of the S2PLOT programming library. The 3-d models can be easily rotated and explored by the reader and, in some cases, modified. We demonstrate example applications of this technique including: 3-d figures exhibiting subtle structure in redshift catalogues, colour-magnitude diagrams and halo merger trees; 3-d isosurface and volume renderings of cosmological simulations; and 3-d models of instructional diagrams and instrument designs.Comment: 18 pages, 7 figures, submitted to New Astronomy. For paper with 3-dimensional embedded figures, see http://astronomy.swin.edu.au/s2plot/3dpd

Hubble and Spitzer Observations of an Edge-on Circumstellar Disk around a Brown Dwarf

We present observations of a circumstellar disk that is inclined close to edge-on around a young brown dwarf in the Taurus star-forming region. Using data obtained with SpeX at the NASA Infrared Telescope Facility, we find that the slope of the 0.8-2.5 um spectrum of the brown dwarf 2MASS J04381486+2611399 cannot be reproduced with a photosphere reddened by normal extinction. Instead, the slope is consistent with scattered light, indicating that circumstellar material is occulting the brown dwarf. By combining the SpeX data with mid-IR photometry and spectroscopy from the Spitzer Space Telescope and previously published millimeter data from Scholz and coworkers, we construct the spectral energy distribution for 2MASS J04381486+2611399 and model it in terms of a young brown dwarf surrounded by an irradiated accretion disk. The presence of both silicate absorption at 10 um and silicate emission at 11 um constrains the inclination of the disk to be ~70 deg, i.e. ~20 deg from edge-on. Additional evidence of the high inclination of this disk is provided by our detection of asymmetric bipolar extended emission surrounding 2MASS J04381486+2611399 in high-resolution optical images obtained with the Hubble Space Telescope. According to our modeling for the SED and images of this system, the disk contains a large inner hole that is indicative of a transition disk (R_in~58 R_star~0.275 AU) and is somewhat larger than expected from embryo ejection models (R_out=20-40 AU vs. R_out<10-20 AU).Comment: The Astrophysical Journal, in pres

CCD-based imaging and 3D space--time mapping of terahertz fields via Kerr frequency conversion

We investigate the spatially and temporally resolved four-wave mixing of terahertz (THz) fields and optical pulses in large-bandgap dielectrics, such as diamond. We show that it is possible to perform beam profiling and space–time resolved mapping of THz fields by encoding the spatial information into an optical signal, which can then be recorded by a standard CCD camera

An Unusual Case of Pleuropulmonary Blastoma in a Child with Jejunal Hamartomas

We report a rare case of 9-month-old girl who presented with a choking episode and was found to have an incidental finding of a lung cyst and iron deficiency anemia leading to the diagnosis of pleuropulmonary blastoma (PPB) and a jejunal hamartoma. Our patient is the eighth that has been reported with the association of PPB with jejunal hamartoma and the first one in the radiological literature. PPB is the pulmonary analog of other dysontogenetic neoplasms in childhood. A biological sequence has been described with the three types of PPB to be interrelated as part of pathologic progression. PPB can be associated with other cysts and/or neoplasms in different organs. PPB is part of a hereditary neoplasia predisposition syndrome in up to 40% of cases. Mutations in DICER gene have been described with PPB. Hence, a pediatric patient diagnosed with PPB should be screened for associated conditions during childhood and adolescence including intestinal polyps. Obtaining family history for other neoplasms or cysts is important information that should raise the possibility of PPB in pediatric patients with cystic lung lesions. The presence of this syndrome should alert the clinician to screen and follow up patients and their relatives

Developing Small Scale Chemistry Practicum Module to Identify Students’ Ability in Predict-Observe- Explain (POE) Implementation

Chemistry practicum does not have to be complicated and requires expensive apparatus and chemicals, and is considered not environmentally friendly. The concept of small scale chemistry practicum is one of appropriate technology that is packaged elegantly to introduce and embed the principles of green chemistry in every chemistry experiments, and also to enhance the concepts of chemistry through verification and scientific discovery. This study aims to create the newest product, the small scale chemistry practicum module to identify the ability of the students of chemistry education study program, Sanata Dharma University, Yogyakarta in formulating predictions on phenomenon based on the insights they have, making direct observations through small scale chemistry practicum, and explaining the results of observations and emphasis on concepts in detail and depth. This research is the development research with the model of Analysis, Design, Develop, Implement, and Evaluate (ADDIE). Data were analyzed by descriptive analysis and Rasch Model. The results of the study show that the product developed has a perfect and feasible level of readability to be tested. From the content aspect, it presented in perfect criteria, as well as the construction aspect and aspect of language, also shows good value. The students already have quite an excellent ability to predict (average score= 76), observe (average score= 88.5), and explain (average score 87.5). Also, it was noted that students enthusiastically applied POE, and the results of POE students show good person reliability value (0.88) in small scale chemistry experiments. The product developed has been valid, effective, and practical for use in experiments according to experts and teachers, and good student responses (Cronbach's alpha value= 0.92) to the product

Assessing Authentically – Learnings From Marketing Educators

This paper demonstrates the importance and role of authentic assessments, that replicate industry practice, within Higher Education marketing programmes. We answer the call from employers, that students need to gain much-needed employability skills, and we illustrate how such assessments can be created to enable the development of employability skills. We provide an overview of four case studies, to illustrate different forms of authentic assessments, the theory which was used to underpin the designs, the skills developed during the assessments, and the outcomes of the assessments. As we emerge from the COVID-19 pandemic, which forced a move to online assessments, it is timely that we reflect on the value of authentic assessments and adjust our practice