A Sino-German 6cm polarisation survey of the Galactic plane IX. HII regions

Large-scale radio continuum surveys provide data to get insights into the physical properties of radio sources. HII regions are prominent radio sources produced by thermal emission of ionised gas around young massive stars. We identify and analyse HII regions in the Sino-German 6cm polarisation survey of the Galactic plane. Objects with flat radio continuum spectra together with infrared and/or Halpha emission were identified as HII regions. For HII regions with small apparent sizes, we cross-matched the 6cm small-diameter source catalogue with the radio HII region catalogue compiled by Paladini and the infrared HII region catalogue based on the WISE data. Extended HII regions were identified by eye by overlaying the Paladini and the WISE HII regions onto the 6cm survey images for coincidences. The TT-plot method was employed for spectral index verification. A total of 401 HII regions were identified and their flux densities were determined with the Sino-German 6cm survey data. In the surveyed area, 76 pairs of sources are found to be duplicated in the Paladini HII region catalogue, mainly due to the non-distinction of previous observations with different angular resolutions, and 78 objects in their catalogue are misclassified as HII regions, being actually planetary nebulae, supernova remnants or extragalactic sources that have steep spectra. More than 30 HII regions and HII region candidates from our 6cm survey data, especially extended ones, do not have counterparts in the WISE HII region catalogue, of which 9 are identified for the first time. Based on the newly derived radio continuum spectra and the evidence of infrared emission, the previously identified SNRs G11.1-1.0, G20.4+0.1 and G16.4-0.5 are believed to be HII regions.Comment: version after some minor corrections and language editing, full Table 2 - 5 will appear in CDS, accepted for publication in A&

Prediction of infectious disease epidemics via weighted density ensembles

Accurate and reliable predictions of infectious disease dynamics can be valuable to public health organizations that plan interventions to decrease or prevent disease transmission. A great variety of models have been developed for this task, using different model structures, covariates, and targets for prediction. Experience has shown that the performance of these models varies; some tend to do better or worse in different seasons or at different points within a season. Ensemble methods combine multiple models to obtain a single prediction that leverages the strengths of each model. We considered a range of ensemble methods that each form a predictive density for a target of interest as a weighted sum of the predictive densities from component models. In the simplest case, equal weight is assigned to each component model; in the most complex case, the weights vary with the region, prediction target, week of the season when the predictions are made, a measure of component model uncertainty, and recent observations of disease incidence. We applied these methods to predict measures of influenza season timing and severity in the United States, both at the national and regional levels, using three component models. We trained the models on retrospective predictions from 14 seasons (1997/1998 - 2010/2011) and evaluated each model's prospective, out-of-sample performance in the five subsequent influenza seasons. In this test phase, the ensemble methods showed overall performance that was similar to the best of the component models, but offered more consistent performance across seasons than the component models. Ensemble methods offer the potential to deliver more reliable predictions to public health decision makers.Comment: 20 pages, 6 figure

The Fragmenting Superbubble Associated with the HII Region W4

New observations at high latitudes above the HII region W4 show that the structure formerly identified as a chimney candidate, an opening to the Galactic halo, is instead a superbubble in the process of fragmenting and possibly evolving into a chimney. Data at high Galactic latitudes (b > 5 degrees) above the W3/W4 star forming region at 1420 and 408 MHz Stokes I (total power) and 1420 MHz Stokes Q and U (linear polarization) reveal an egg-shaped structure with morphological correlations between our data and the H-alpha data of Dennison, Topasna, & Simonetti. Polarized intensity images show depolarization extending from W4 up the walls of the superbubble, providing strong evidence that the radio continuum is generated by thermal emission coincident with the H-alpha emission regions. We conclude that the parts of the HII region hitherto known as W4 and the newly revealed thermal emission are all ionized by the open cluster OCl 352. Assuming a distance of 2.35 kpc, the ovoid structure is 164 pc wide and extends 246 pc above the mid-plane of the Galaxy. The shell's emission decreases in total-intensity and polarized intensity in various locations, appearing to have a break at its top and another on one side. Using a geometric analysis of the depolarization in the shell's walls, we estimate that a magnetic field line-of-sight component of 3 to 5 uG exists in the shell. We explore the connection between W4 and the Galactic halo, considering whether sufficient radiation can escape from the fragmenting superbubble to ionize the kpc-scale H-alpha loop discovered by Reynolds, Sterling & Haffner.Comment: 42 pages, 14 figures; Accepted for publication in Ap

Evaluation of remote sensing techniques on selected forest sites in Florida

There are no author-identified significant results in this report

G55.0+0.3: A Highly Evolved Supernova Remnant

Multi-frequency analysis has revealed the presence of a new supernova remnant, G55.0+0.3, in the Galactic plane. A kinematic distance of 14 kpc has been measured from HI spectral line data. The faint, clumpy half-shell is non-thermal and has a physical radius of 70 pc. Using an evolutionary model, the age of the remnant is estimated to be on the order of one million years, which exceeds conventional limits by a factor of five. The remnant may be associated with the nearby pulsar J1932+2020, which has a spin-down age of 1.1 million years. This work implies that the radiative lifetimes of remnants could be much longer than previously suggested.Comment: 27 pages, 7 figures in 9 files (figures 1 and 2 require 2 files each), Accepted for publication in The Astrophysical Journal (Jan. 20, 1998 volume

Observation of magnetism in Au thin films

Direct magnetization measurements of thin gold films are presented. These measurements integrate the signal from the thin film under study and the magnetic contribution of the film's interface with the substrate. The diamagnetic contribution to the signal from the bulk substrate is of the same order as the noise level. we find that thin gold films can exhibit positive magnetization. The character of their magnetic behavior is strongly substrate dependent.Comment: 9 pages, 4 figure