46 research outputs found
CANDELS multi-wavelength catalogs: source identification and photometry in the CANDELS COSMOS survey field
We present a multi-wavelength photometric catalog in the COSMOS field as part of the observations by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. The catalog is based on Hubble Space Telescope Wide Field Camera 3 (HST/WFC3) and Advanced Camera for Surveys observations of the COSMOS field (centered at R.A.: 10h00m28s, Decl.:+02h12m21s). The final catalog has 38671 sources with photometric data in 42 bands from UV to the infrared (~0.3-8 ÎĽm). This includes broadband photometry from HST, CFHT, Subaru, the Visible and Infrared Survey Telescope for Astronomy, and Spitzer Space Telescope in the visible, near-infrared, and infrared bands along with intermediate- and narrowband photometry from Subaru and medium-band data from Mayall NEWFIRM. Source detection was conducted in the WFC3 F160W band (at 1.6 ÎĽm) and photometry is generated using the Template FITting algorithm. We further present a catalog of the physical properties of sources as identified in the HST F160W band and measured from the multi-band photometry by fitting the observed spectral energy distributions of sources against templates
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Changes in northern hemisphere temperature variability shaped by regional warming patterns
Global warming involves changes not only in the mean atmospheric temperature, but also in its variability and extremes. Here we use a feature-tracking technique to investigate the dynamical contribution to temperature anomalies in the northern hemisphere in CMIP5 climate-change simulations. We develop a simple theory to explain how temperature variance and skewness changes are generated dynamically from mean temperature gradient changes, and demonstrate the crucial role of regional warming patterns in shaping the distinct response of cold and warm anomalies. We also show that skewness changes must be taken into account, in addition to variance changes, in order to correctly capture the projected temperature variability response. These changes in variability may impact humans, agriculture and animals, as they experience not only a warmer mean climate, but also a new likelihood of temperature anomalies within that climate
Stability of oligodeoxynucleoside phosphorodithioates and phosphorothioates in aqueous ammonia.
Oligonucleotide analogues like oligodeoxynucleoside phospho-rothioates and phosphorodithioates (Fig. 1) are of interest for antisense applications (1). Efficient methods exist for the preparation of both analogues, but the products often contain less sulfur than intended, as shown by the presence of variable amounts of phosphate linkages in oligonucleoside phosphoro-thioates, and phosphorothioate linkages in oligonucleoside phos-phorodithioates. Incomplete oxidation by the sulfurization reagents used in phosphoramidite or thiophosphoramidite methods could explain the appearance of these impurities, but cannot explain why products prepared by triester methods are also often contaminated. We have recently described a dithiophosphortriester method that gives oligodeoxynucleoside phosphorodithioates free of phosphorothioate impurities (2). However, when the oligonu-cleoside phosphorodithioates were kept in prolonged contact wit
The impact of processing on the cytotoxicity of graphene oxide
In-house prepared graphene oxide (GO) was processed via base washing, sonication, cleaning and combinations of these processing techniques to evaluate the impact on the flake morphology, composition and cytotoxicity of the material. The flakes of unprocessed GO were relatively planar, but upon base washing, the flakes became textured exhibiting many folds and creases observed by AFM. In addition to the pronounced effect on the topography, base washing increased the C/O ratio and increased the cytotoxicity of GO on all four cell lines studied determined via the WST-8 assay. Sonicating the unprocessed and base washed samples resulted in smaller flakes with a similar topography; the base washed flakes lost the texture previously observed upon sonication. The sonicated samples were more toxic than the unprocessed sample, attributed to the smaller flake size, but were interestingly less toxic than the base washed, unsonicated sample despite the base washed unsonicated sample having a larger flake size. This unexpected finding was confirmed by a second analyst using the same, and a different source of GO and resulted in the conclusion that the morphology of GO greatly impacts the cytotoxicity. Cleaning the GO reduced the amount of nitrogen and sulfur impurities in the sample but had no significan