The ionizing sources of luminous compact HII regions in the RCW106 and RCW122 clouds

Given the rarity of young O star candidates, compact HII regions embedded in dense molecular cores continue to serve as potential sites to peer into the details of high-mass star formation. To uncover the ionizing sources of the most luminous and compact HII regions embedded in the RCW106 and RCW122 giant molecular clouds, known to be relatively nearby (2-4 kpc) and isolated, thus providing an opportunity to examine spatial scales of a few hundred to a thousand AU in size. High spatial resolution (0.3"), mid-infrared spectra (R=350), including the fine structure lines [ArIII] and [NeII], were obtained for four luminous compact HII regions, embedded inside the dense cores within the RCW106 and RCW122 molecular cloud complexes. At this resolution, these targets reveal point-like sources surrounded by nebulosity of different morphologies, uncovering details at spatial dimensions of <1000AU. The point-like sources display [ArIII] and [NeII] lines - the ratios of which are used to estimate the temperature of the embedded sources. The derived temperatures are indicative of mid-late O type objects for all the sources with [ArIII] emission. Previously known characteristics of these targets from the literature, including evidence of disk or accretion suggest that the identified sources may grow more to become early-type O stars by the end of the star formation process

Contribution of Grasses to Soil Fertility and Improved Livelihoods

Vegetable farming is increasing in Nepal as it provides better economic returns than growing other crops, especially in areas that have easy access to markets. Vegetable farming demands intensive care and balanced supplies of nutrients. Therefore, farmers cultivate vegetables near their residence and because vegetable growing is more profitable, farmers allocate more resources, including organic manure, for its cultivation. In general, using more organic manure on vegetables means that less organic manure is available for non-vegetable crops and farms, unless alternative arrangements are made for producing more organic manure or manure of higher quality

An in vitro comparison of the hemodynamics of two inferior vena cava filters

AbstractPurpose: The effectiveness of an inferior vena cava (IVC) filter in preventing pulmonary embolism while preserving caval flow is significantly affected by its hemodynamic characteristics. Flow fields surrounding two types of IVC filters were compared to assess how the design of a filter may influence performance. Methods: The 12F Titanium Greenfield and VenaTech LGM inferior vena cava filters were studied in vitro with a noninvasive flow visualization technique, the photochromic flow visualization and measurement technique. Axial velocity profiles and wall shear stress distributions were measured. These results were compared with analytical data corresponding to the flow field in the absence of a filter to determine the relative extent of the flow disturbances. Results: The reductions in near-wall axial velocity and wall shear stress caused by the VenaTech filter were more extensive and severe than those caused by the Greenfield filter. These changes were the consequence of differences in the geometry and dimensions of the struts of the two filters. The measurements showed the flow fields to be laminar, with no evidence of turbulence in both cases. Conclusion: Two factors that have been linked to thrombogenesis, near-wall velocity and wall-shear stress, were significantly affected by the larger frontal profile area of the VenaTech filter. Although a larger area may increase clot-trapping efficiency, as shown by previous studies, the reduced near-wall velocities and wall shear stresses may increase the potential for thrombogenesis and, thus, caval occlusion. In contrast to other in vitro flow visualization studies, no turbulence was observed with either filter. (J Vasc Surg 2000;31:539-49.

High Resolution Rapid Response observations of compact radio sources with the Ceduna Hobart Interferometer (CHI)

Context. Frequent, simultaneous observations across the electromagnetic spectrum are essential to the study of a range of astrophysical phenomena including Active Galactic Nuclei. A key tool of such studies is the ability to observe an object when it flares i.e. exhibits a rapid and significant increase in its flux density. Aims. We describe the specific observational procedures and the calibration techniques that have been developed and tested to create a single baseline radio interferometer that can rapidly observe a flaring object. This is the only facility that is dedicated to rapid high resolution radio observations of an object south of -30 degrees declination. An immediate application is to provide rapid contemporaneous radio coverage of AGN flaring at {\gamma}-ray frequencies detected by the Fermi Gamma-ray Space Telescope. Methods. A single baseline interferometer was formed with radio telescopes in Hobart, Tasmania and Ceduna, South Australia. A software correlator was set up at the University of Tasmania to correlate these data. Results. Measurements of the flux densities of flaring objects can be made using our observing strategy within half an hour of a triggering event. These observations can be calibrated with amplitude errors better than 15%. Lower limits to the brightness temperatures of the sources can also be calculated using CHI.Comment: 6 pages, 6 figures, 1 table. Accepted for publication in A&

Comparing Deep Recurrent Networks Based on the MAE Random Sampling, a First Approach

Recurrent neural networks have demonstrated to be good at tackling prediction problems, however due to their high sensitivity to hyper-parameter configuration, finding an appropriate network is a tough task. Automatic hyper-parameter optimization methods have emerged to find the most suitable configuration to a given problem, but these methods are not generally adopted because of their high computational cost. Therefore, in this study we extend the MAE random sampling, a low-cost method to compare single-hidden layer architectures, to multiple-hidden-layer ones. We validate empirically our proposal and show that it is possible to predict and compare the expected performance of an hyper-parameter configuration in a low-cost way.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This research was partially funded by Ministerio de Economı́a, Industria y Competitividad, Gobierno de España, and European Regional Development Fund grant numbers TIN2016-81766-REDT (http://cirti.es) and TIN2017-88213-R (http://6city.lcc.uma.es)

A multi-wavelength study of star formation activity in the S235 complex

We have carried out an extensive multi-wavelength study to investigate the star formation process in the S235 complex. The S235 complex has a sphere-like shell appearance at wavelengths longer than 2 $\mu$m and harbors an O9.5V type star approximately at its center. Near-infrared extinction map traces eight subregions (having A$_{V}$ $>$ 8 mag), and five of them appear to be distributed in an almost regularly spaced manner along the sphere-like shell surrounding the ionized emission. This picture is also supported by the integrated $^{12}$CO and $^{13}$CO intensity maps and by Bolocam 1.1 mm continuum emission. The position-velocity analysis of CO reveals an almost semi-ring like structure, suggesting an expanding H\,{\sc ii} region. We find that the Bolocam clump masses increase as we move away from the location of the ionizing star. This correlation is seen only for those clumps which are distributed near the edges of the shell. Photometric analysis reveals 435 young stellar objects (YSOs), 59\% of which are found in clusters. Six subregions (including five located near the edges of the shell) are very well correlated with the dust clumps, CO gas, and YSOs. The average values of Mach numbers derived using NH$_{3}$ data for three (East~1, East~2, and Central~E) out of these six subregions are 2.9, 2.3, and 2.9, indicating these subregions are supersonic. The molecular outflows are detected in these three subregions, further confirming the on-going star formation activity. Together, all these results are interpreted as observational evidence of positive feedback of a massive star.Comment: 28 pages, 15 figures, 3 tables, Accepted for publication in The Astrophysical Journa