Infrared Echoes near the Supernova Remnant Cassiopeia A

Two images of Cassiopeia A obtained at 24 micrometer with the Spitzer Space Telescope over a one year time interval show moving structures outside the shell of the supernova remnant to a distance of more than 20 arcmin. Individual features exhibit apparent motions of 10 to 20 arcsec per year, independently confirmed by near-infrared observations. The observed tangential velocities are at roughly the speed of light. It is likely that the moving structures are infrared echoes, in which interstellar dust is heated by the explosion and by flares from the compact object near the center of the remnant.Comment: To be published in Science on June 10, 2005. 11 pages, 4 figures. Additional information available at http://www.spitzer.caltech.edu/Media/releases/ssc2005-14/index.shtm

JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B

We present 1-5um spectroscopy of the young planetary mass companion TWA 27B (2M1207B) performed with NIRSpec on board the James Webb Space Telescope. In these data, the fundamental band of CH_4 is absent and the fundamental band of CO is weak. The nondetection of CH_4 reinforces a previously observed trend of weaker CH_4 with younger ages among L dwarfs, which has been attributed to enhanced non-equilibrium chemistry among young objects. The weakness of CO may reflect an additional atmospheric property that varies with age, such as the temperature gradient or cloud thickness. We are able to reproduce the broad shape of the spectrum with an ATMO cloudless model that has T=1300 K, non-equilibrium chemistry, and a temperature gradient reduction caused by fingering convection. However, the fundamental bands of CH_4 and CO are somewhat stronger in the model. In addition, the model temperature of 1300 K is higher than expected from evolutionary models given the luminosity and age of TWA 27B (T=1200 K). Previous models of young L-type objects suggest that the inclusion of clouds could potentially resolve these issues; it remains to be seen whether cloudy models can provide a good fit to the 1-5um data from NIRSpec. TWA 27B exhibits emission in Paschen transitions and the He I triplet at 1.083um, which are signatures of accretion that provide the first evidence of a circumstellar disk. We have used the NIRSpec data to estimate the bolometric luminosity of TWA 27B (log L/L_sun=-4.466+/-0.014), which implies a mass of 5-6 MJup according to evolutionary models.Comment: Astrophysical Journal Letters, in pres

Developing an impact library for forecasting surface water flood risk

During surface water flooding events, emergency responders require detailed information on the risks posed in order to provide an appropriate and effective response. Few early warning systems quantitatively estimate the risk and impacts of surface water flooding. Improvements in computational processing capability, availability of new datasets and developments in forecasting models means that the forecasting information currently being supplied by the Flood Forecasting Centre can be improved upon through the application of a timely, impact‐based model. This article presents a novel approach to collating receptor datasets into a pre‐calculated Impact Library for use in a Hazard Impact Model (HIM) that will operate using real‐time probabilistic rainfall and surface runoff forecasts for England and Wales. The HIM provides an approach suitable for modelling flood impacts. Initial results are presented for a case study covering the 2012 floods in the North East of England. Information generated by the HIM provides additional benefits beyond current methods. Features include operator access to 1 km 15 min spatial–temporal data, analysis of individual impact criteria and modular refinement of the Impact Library to suit different situations. The HIM has been developed in partnership via the Natural Hazards Partnership

Global vulnerability hotspots: differences and agreement between international indicator-based assessments

Climate change impacts and their consequences are determined not only by the intensity and frequency of different climatic hazards but also by the vulnerability of the system, society or community exposed. While general agreement exists about the importance of assessing vulnerability to understand climate risks, there is still a tendency to neglect global and regional vulnerability patterns because they are hard to quantify, despite their value in informing adaptation, disaster risk and development policies. Several approaches to quantifying global vulnerability exist. These differ in terms of the indicators they use and how they classify countries or regions into vulnerability classes. The paper presents the structure of selected approaches and explores two indices in depth. The aim of this paper is to assess the level of agreement between selected international indicator-based assessments of vulnerability, at the level of climate regions. Results suggest that the two major global vulnerability assessments analysed largely agree on the location of the most and least vulnerable regions when these assessments are aggregated to a regional scale using the IPCC’s climate regions. The paper then discusses the robustness of the information derived and its usefulness for adaptation, disaster risk and development policies. Measuring progress towards reducing vulnerability to climate change and hazards is key for various agencies and actors in order to be able to develop informed policies and strategies for managing climate risks and to promote enabling conditions for achieving the SDGs and building resilience

Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program

The James Webb Space Telescope will revolutionize transiting exoplanet atmospheric science due to its capability for continuous, long-duration observations and its larger collecting area, spectral coverage, and spectral resolution compared to existing space-based facilities. However, it is unclear precisely how well JWST will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. In this article, we describe a prefatory JWST Early Release Science (ERS) program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful future transiting exoplanet characterization programs. We propose a multi-pronged approach wherein one aspect of the program focuses on observing transits of a single target with all of the recommended observing modes to identify and understand potential systematics, compare transmission spectra at overlapping and neighboring wavelength regions, confirm throughputs, and determine overall performances. In our search for transiting exoplanets that are well suited to achieving these goals, we identify 12 objects (dubbed "community targets") that meet our defined criteria. Currently, the most favorable target is WASP-62b because of its large predicted signal size, relatively bright host star, and location in JWST's continuous viewing zone. Since most of the community targets do not have well-characterized atmospheres, we recommend initiating preparatory observing programs to determine the presence of obscuring clouds/hazes within their atmospheres. Measurable spectroscopic features are needed to establish the optimal resolution and wavelength regions for exoplanet characterization. Other initiatives from our proposed ERS program include testing the instrument brightness limits and performing phase-curve observations.(Abridged)Comment: This is a white paper that originated from an open discussion at the Enabling Transiting Exoplanet Science with JWST workshop held November 16 - 18, 2015 at STScI (http://www.stsci.edu/jwst/science/exoplanets). Accepted for publication in PAS

Detection of Prion Protein Particles in Blood Plasma of Scrapie Infected Sheep

Prion diseases are transmissible neurodegenerative diseases affecting humans and animals. The agent of the disease is the prion consisting mainly, if not solely, of a misfolded and aggregated isoform of the host-encoded prion protein (PrP). Transmission of prions can occur naturally but also accidentally, e.g. by blood transfusion, which has raised serious concerns about blood product safety and emphasized the need for a reliable diagnostic test. In this report we present a method based on surface-FIDA (fluorescence intensity distribution analysis), that exploits the high state of molecular aggregation of PrP as an unequivocal diagnostic marker of the disease, and show that it can detect infection in blood. To prepare PrP aggregates from blood plasma we introduced a detergent and lipase treatment to separate PrP from blood lipophilic components. Prion protein aggregates were subsequently precipitated by phosphotungstic acid, immobilized on a glass surface by covalently bound capture antibodies, and finally labeled with fluorescent antibody probes. Individual PrP aggregates were visualized by laser scanning microscopy where signal intensity was proportional to aggregate size. After signal processing to remove the background from low fluorescence particles, fluorescence intensities of all remaining PrP particles were summed. We detected PrP aggregates in plasma samples from six out of ten scrapie-positive sheep with no false positives from uninfected sheep. Applying simultaneous intensity and size discrimination, ten out of ten samples from scrapie sheep could be differentiated from uninfected sheep. The implications for ante mortem diagnosis of prion diseases are discussed

Prognostic impact of meningeal dissemination in primary CNS lymphoma (PCNSL): experience from the G-PCNSL-SG1 trial

Background We evaluated the frequency and prognostic impact of meningeal dissemination (MD) in immunocompetent adult patients with primary central nervous system lymphoma treated in a randomized phase III trial. Patients and methods MD was evaluated at study entry and defined by lymphoma proof in the meningeal compartment detected by at least one of the following methods: cerebrospinal fluid (CSF) cytomorphology, detection of clonal B cells by IgH PCR in CSF or contrast enhancement of the leptomeninges on magnetic resonance imaging (MRI). Results Data on MD were available in 415 patients, of those, MD was detected in 65 (15.7%): in 44/361 (12.2%) by CSF cytomorphology, in 16/152 (10.5%) by PCR and in 17/415 (4.1%) by MRI. Major patients' characteristics and therapy did not significantly differ between patients with MD (MD+) versus those without MD (MD−). There was a significant correlation of MD with CSF pleocytosis (>5/μl; P45 mg/dl). Median progression-free survival was 6.7 months [95% confidence interval (CI) 0-14.5] in MD+ and 8.3 months (5.7-10.8) in MD− patients (P=0.95); median overall survival was 21.5 months (95% CI 16.8-26.1) and 24.9 months (17.5-32.3), respectively (P=0.98). Conclusion MD was detected infrequently and had no impact on outcome in this tria

Molecular Interactions between Prions as Seeds and Recombinant Prion Proteins as Substrates Resemble the Biological Interspecies Barrier In Vitro

Prion diseases like Creutzfeldt-Jakob disease in humans, Scrapie in sheep or bovine spongiform encephalopathy are fatal neurodegenerative diseases, which can be of sporadic, genetic, or infectious origin. Prion diseases are transmissible between different species, however, with a variable species barrier. The key event of prion amplification is the conversion of the cellular isoform of the prion protein (PrPC) into the pathogenic isoform (PrPSc). We developed a sodiumdodecylsulfate-based PrP conversion system that induces amyloid fibril formation from soluble α-helical structured recombinant PrP (recPrP). This approach was extended applying pre-purified PrPSc as seeds which accelerate fibrillization of recPrP. In the present study we investigated the interspecies coherence of prion disease. Therefore we used PrPSc from different species like Syrian hamster, cattle, mouse and sheep and seeded fibrillization of recPrP from the same or other species to mimic in vitro the natural species barrier. We could show that the in vitro system of seeded fibrillization is in accordance with what is known from the naturally occurring species barriers

Vulnerability to natural disasters in Serbia: spatial and temporal comparison

The frequency of natural disasters and the extent of their consequences at a global level are constantly increasing. This trend is partially caused by increased population vulnerability, which implies the degree of population vulnerability due to high magnitude natural processes. This paper presents an analysis of vulnerability to natural disaster in Serbia in the second half of the twentieth and the early twenty-first century. Vulnerability changes were traced on the basis of demographic–economic indicators derived from statistical data for local government units (municipalities) provided by the Statistical Office of the Republic of Serbia. Calculations were performed in the geographical information system environment. The results of the study show that spatial and temporal vulnerability variations are causally correlated with changes in the selected components. Significant rise of vulnerability is related to urban areas, while lower values are characteristic for other areas of Serbia; this is primarily a consequence of different population density