Ices in the edge-on disk CRBR 2422.8-3423: Spitzer spectroscopy and Monte Carlo radiative transfer modeling

We present 5.2-37.2 micron spectroscopy of the edge-on circumstellar disk CRBR 2422.8-3423 obtained using the InfraRed Spectrograph (IRS) of the Spitzer Space Telescope. The IRS spectrum is combined with ground-based 3-5 micron spectroscopy to obtain a complete inventory of solid state material present along the line of sight toward the source. We model the object with a 2D axisymmetric (effectively 3D) Monte Carlo radiative transfer code. It is found that the model disk, assuming a standard flaring structure, is too warm to contain the very large observed column density of pure CO ice, but is possibly responsible for up to 50% of the water, CO2 and minor ice species. In particular the 6.85 micron band, tentatively due to NH4+, exhibits a prominent red wing, indicating a significant contribution from warm ice in the disk. It is argued that the pure CO ice is located in the dense core Oph-F in front of the source seen in the submillimeter imaging, with the CO gas in the core highly depleted. The model is used to predict which circumstances are most favourable for direct observations of ices in edge-on circumstellar disks. Ice bands will in general be deepest for inclinations similar to the disk opening angle, i.e. ~70 degrees. Due to the high optical depths of typical disk mid-planes, ice absorption bands will often probe warmer ice located in the upper layers of nearly edge-on disks. The ratios between different ice bands are found to vary by up to an order of magnitude depending on disk inclination due to radiative transfer effects caused by the 2D structure of the disk. Ratios between ice bands of the same species can therefore be used to constrain the location of the ices in a circumstellar disk. [Abstract abridged]Comment: 49 pages, accepted for publication in Ap

Spatial Effects of Permethrin-Impregnated Bed Nets on Child Mortality: 26 Years on, a Spatial Reanalysis of a Cluster Randomized Trial.

In addition to the direct effect of insecticide-treated nets (ITNs), there has been evidence for spatial indirect effects. Spatial analyses in cluster randomized trials (CRTs) are rare, but a large-scale CRT from 1993 was one of the first to conduct a spatial analysis of ITNs in CRTs. We revisit these data by applying a broader range of contemporary spatial methods to further explore spatial spillover. We conducted three analyses: 1) exploratory spatial analysis, considering spatial patterns and spillover in the data; 2) spatial modeling, estimating the intervention effect considering spatial effects; and 3) analysis of distance-based spillover and interaction with the intervention, characterizing the functional distance over which the spillover effect was present. There were consistent indications of spatial patterns from the exploratory analysis. Bed nets were associated with a 17% reduction in all-cause mortality for children aged 6-59 months, and the intervention estimate remained robust when allowing for the spatial structure of the data. There was strong evidence of a spatial spillover effect: for every additional 100 m that a control household was from an intervention household (and vice versa), the standardized mortality ratio (SMR) increased by 1.7% (SMR 1.017, 95% credible interval 1.006-1.026). Despite evidence of a spatial spillover effect, the conclusions of the trial remain unaffected by spatial model specifications. Use of ITNs was clearly beneficial for individuals, and there was compelling evidence that they provide an indirect benefit to individuals living nearby. This article demonstrates the extra utility that spatial methods can provide when analyzing a CRT

The c2d Spitzer Spectroscopic Survey Of Ices Around Low-Mass Young Stellar Objects. I. H2O And The 5-8 Mu M Bands

To study the physical and chemical evolution of ices in solar-mass systems, a spectral survey is conducted of a sample of 41 low-luminosity YSOs (L similar to 0.1-10 L-circle dot) using 3-38 mu m Spitzer and ground-based spectra. The sample is complemented with previously published Spitzer spectra of background stars and with ISO spectra of well-studied massive YSOs (L similar to 10(5) L-circle dot). The long-known 6.0 and 6.85 mu m bands are detected toward all sources, with the Class 0-type YSOs showing the deepest bands ever observed. The 6.0 mu m band is often deeper than expected from the bending mode of pure solid H2O. The additional 5-7 mu m absorption consists of five independent components, which, by comparison to laboratory studies, must be from at least eight different carriers. Much of this absorption is due to simple species likely formed by grain surface chemistry, at abundances of 1%-30% for CH3OH, 3%-8% for NH3, 1%-5% for HCOOH, similar to 6% for H2CO, and similar to 0.3% for HCOO- relative to solid H2O. The 6.85 mu m band has one or two carriers, of which one may be less volatile than H2O. Its carrier(s) formed early in the molecular cloud evolution and do not survive in the diffuse ISM. If an NH4+- containing salt is the carrier, its abundance relative to solid H2O is similar to 7%, demonstrating the efficiency of low-temperature acid-base chemistry or cosmic-ray-induced reactions. Possible origins are discussed for enigmatic, very broad absorption between 5 and 8 mu m. Finally, the same ices are observed toward massive and low-mass YSOs, indicating that processing by internal UV radiation fields is a minor factor in their early chemical evolution.NWO SpinozaNOVAEuropean Research Training Network PLANETS HPRN-CT-2002-00308NASA Origins NAG5-13050NASA Hubble Fellowship 01201.01NASA NAS 5-26555Astronom

C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth

Infrared ~5--35 um spectra for 40 solar-mass T Tauri stars and 7 intermediate-mass Herbig Ae stars with circumstellar disks were obtained using the Spitzer Space Telescope as part of the c2d IRS survey. This work complements prior spectroscopic studies of silicate infrared emission from disks, which were focused on intermediate-mass stars, with observations of solar-mass stars limited primarily to the 10 um region. The observed 10 and 20 um silicate feature strengths/shapes are consistent with source-to-source variations in grain size. A large fraction of the features are weak and flat, consistent with um-sized grains indicating fast grain growth (from 0.1--1.0 um in radius). In addition, approximately half of the T Tauri star spectra show crystalline silicate features near 28 and 33 um indicating significant processing when compared to interstellar grains. A few sources show large 10-to-20 um ratios and require even larger grains emitting at 20 um than at 10 um. This size difference may arise from the difference in the depth into the disk probed by the two silicate emission bands in disks where dust settling has occurred. The 10 um feature strength vs. shape trend is not correlated with age or Halpha equivalent width, suggesting that some amount of turbulent mixing and regeneration of small grains is occurring. The strength vs. shape trend is related to spectral type, however, with M stars showing significantly flatter 10 um features (larger grain sizes) than A/B stars. The connection between spectral type and grain size is interpreted in terms of the variation in the silicate emission radius as a function of stellar luminosity, but could also be indicative of other spectral-type dependent factors (e.g, X-rays, UV radiation, stellar/disk winds, etc.).Comment: 17 pages, 13 figures, accepted for publication by ApJ, formatted with emulateapj using revtex4 v4.

Spitzer Mid-infrared Spectroscopy of Ices Toward Extincted Background Stars

A powerful way to observe directly the solid state inventory of dense molecular clouds is by infrared spectroscopy of background stars. We present Spitzer/IRS 5-20 micron spectra of ices toward stars behind the Serpens and Taurus molecular clouds, probing visual extinctions of 10-34 mag. These data provide the first complete inventory of solid-state material in dense clouds before star formation begins. The spectra show prominent 6.0 and 6.85 micron bands. In contrast to some young stellar objects (YSOs), most (~75%) of the 6.0 micron band is explained by the bending mode of pure water ice. In realistic mixtures this number increases to 85%, because the peak strength of the water bending mode is very sensitive to the molecular environment. The strength of the 6.85 micron band is comparable to what is observed toward YSOs. Thus, the production of the carrier of this band does not depend on the energetic input of a nearby source. The spectra show large abundances of carbon monoxide and carbon dioxide (20-40% with respect to water ice). Compared to YSOs, the band profile of the 15 micron carbon dioxide bending mode lacks the signatures of crystallization, confirming the cold, pristine nature of these lines of sight. After the dominant species are removed, there are residuals that suggest the presence of minor species such as formic acid and possibly ammonia. Clearly, models of star formation should begin with dust models already coated with a fairly complex mixture of ices.Comment: 4 pages, 5 figures; To appear in Astrophysical Journal Letter

The Society for Immunotherapy of Cancer consensus statement on immunotherapy for the treatment of non-small cell lung cancer (NSCLC)

Lung cancer is the leading cause of cancer-related mortality worldwide, with non-small cell lung cancer (NSCLC) accounting for over 85% of all cases. Until recently, chemotherapy – characterized by some benefit but only rare durable responses – was the only treatment option for patients with NSCLC whose tumors lacked targetable mutations. By contrast, immune checkpoint inhibitors have demonstrated distinctly durable responses and represent the advent of a new treatment approach for patients with NSCLC. Three immune checkpoint inhibitors, pembrolizumab, nivolumab and atezolizumab, are now approved for use in first- and/or second-line settings for selected patients with advanced NSCLC, with promising benefit also seen in patients with stage III NSCLC. Additionally, durvalumab following chemoradiation has been approved for use in patients with locally advanced disease. Due to the distinct features of cancer immunotherapy, and rapid progress in the field, clinical guidance is needed on the use of these agents, including appropriate patient selection, sequencing of therapies, response monitoring, adverse event management, and biomarker testing. The Society for Immunotherapy of Cancer (SITC) convened an expert Task Force charged with developing consensus recommendations on these key issues. Following a systematic process as outlined by the National Academy of Medicine, a literature search and panel voting were used to rate the strength of evidence for each recommendation. This consensus statement provides evidence-based recommendations to help clinicians integrate immune checkpoint inhibitors into the treatment plan for patients with NSCLC. This guidance will be updated following relevant advances in the field

Basic Atomic Physics

Contains reports on five research projects.Joint Services Electronics Program Contract DAAL03-92-C-0001Joint Services Electronics Program Grant DAAH04-95-1-0038National Science Foundation Grant PHY 92-21489U.S. Navy - Office of Naval Research Grant N00014-90-J-1322National Science Foundation Grant PHY 92-22768U.S. Army - Office of Scientific Research Grant DAAL03-92-G-0229U.S. Army - Office of Scientific Research Grant DAAL01-92-6-0197U.S. Navy - Office of Naval Research Grant N00014-89-J-1207Alfred P. Sloan FoundationU.S. Navy - Office of Naval Research Grant N00014-90-J-1642U.S. Navy - Office of Naval Research Grant N00014-94-1-080

Basic Atomic Physics

Contains reports on five research projects.National Science Foundation Grant PHY 89-19381National Science Foundation Grant PHY 92-21489U.S. Navy - Office of Naval Research Grant N00014-90-J-1322Joint Services Electronics Program Contract DAAL03-92-C-0001National Science Foundation Grant PHY 89-21769U.S. Army - Office of Scientific Research Grant DAAL03-92-G-0229U.S. Navy - Office of Naval Research Grant N00014-89-J-1207U.S. Navy - Office of Naval Research Grant N00014-90-J-164

Basic Atomic Physics

Contains reports on five research projects.Joint Services Electronics Program Grant DAAH04-95-1-0038National Science Foundation Grant PHY 92-21489U.S. Navy - Office of Naval Research Grant N00014-90-J-1322National Science Foundation Grant PHY95-14795Charles S. Draper Laboratory Contract DL-H-484775U.S. Army Research Office Contract DAAH04-94-G-0170U.S. Army Research Office Contract DAAH04-95-1-0533U.S. Navy - Office of Naval Research Contract N00014-89-J-1207U.S. Navy - Office of Naval Research Contract N000014-96-1-0432David and Lucile Packard Foundation Grant 96-5158National Science Foundation Grant PHY95-01984U.S. Army - Office of ResearchU.S. Navy - Office of Naval Research Contract N00014-96-1-0485U.S. Navy - Office of Naval Research AASERT N00014-94-1-080

Basic Atomic Physics

Contains reports on five research projects.Joint Services Electronics Program Grant DAAH04-95-1-0038National Science Foundation Grant PHY 92-21489U.S. Navy - Office of Naval Research Grant N00014-90-J-1322National Science Foundation Grant PHY 92-22768Charles S. Draper Laboratory Contract DL-H-4847759U.S. Army - Office of Scientific Research Grant DAAL03-92-G-0229U.S. Army - Office of Scientific Research Grant DAAL01-92-6-0197U.S. Navy - Office of Naval Research Grant N00014-89-J-1207Alfred P. Sloan FoundationNational Science Foundation Grant PHY 95-01984U.S. Army Research Office Contract DAAL01-92-C-0001U.S. Navy - Office of Naval Research Grant N00014-90-J-1642U.S. Navy - Office of Naval Research Grant N00014-94-1-080