scholarly journals Updated radio Σ−D relation for galactic supernova remnants

2014 ◽  
pp. 25-40 ◽  
Author(s):  
M.Z. Pavlovic ◽  
A. Dobardzic ◽  
B. Vukotic ◽  
D. Urosevic
Keyword(s):  
Supernova Remnants ◽  
Galactic Plane ◽  
Empirical Relation ◽  
Data Sets ◽  
Orthogonal Regression ◽  
Fitting Procedure ◽  
Density Maps ◽  
Calibration Sample ◽  
Data Points ◽  
First Time

We present the updated empirical radio surface-brightness-to-diameter (? ? D) relation for supernova remnants (SNRs) in our Galaxy. Our original calibration sample of Galactic SNRs with independently determined distances (Pavlovic et al. 2013, hereafter Paper I) is reconsidered and updated with data which became available in the past two years. The orthogonal fitting procedure and probability-density-function-based (PDF) method are applied to the calibration sample in the log? ? logD plane. Non-standard orthogonal regression keeps the ??D and D?? relations invariant within estimated uncertainties. Our previous Monte Carlo simulations verified that the slopes of the empirical ??D relation should be determined by using the orthogonal regression, because of its good performances for data sets with severe scatter. The updated calibration sample contains 65 shell SNRs. 6 new Galactic SNRs are added to the sample from Paper I, one is omitted and distances are changed for 10 SNRs. The slope derived is here slightly steeper (? ? 5.2) than the ??D slope in Paper I (? ? 4.8). The PDF method relies on data points density maps which can provide more reliable calibrations that preserve more information contained in the calibration sample. We estimate distances to five new faint Galactic SNRs discovered for the first time by Canadian Galactic Plane Survey, and obtained distances of 2.3, 4.0, 1.3, 2.9 and 4.7 kiloparsecs for G108.5+11.0, G128.5+2.6, G149.5+3.2, G150.8+3.8 and G160.1?1.1, respectively. The updated empirical relation is used to estimate distances of 160 shell Galactic SNRs and new results change their distance scales up to 15 per cent, compared to the results from Paper I. The PDF calculation can provide even few times higher or lower values in comparison with the orthogonal fit, as it uses a totally different approach. However, on average, this difference is 32, 24 and 18 per cent for mode, median and mean distances.

scholarly journals An overview of heavy-atom derivatization of protein crystals

2016 ◽  
Vol 72 (3) ◽  
pp. 303-318 ◽  
Author(s):  
Ashley C. W. Pike ◽  
Elspeth F. Garman ◽  
Tobias Krojer ◽  
Frank von Delft ◽  
Elisabeth P. Carpenter
Keyword(s):  
Heavy Atom ◽  
Protein Crystals ◽  
Data Sets ◽  
Low Resolution ◽  
Heavy Atoms ◽  
Density Maps ◽  
Resolution Electron ◽  
First Choice ◽  
First Time ◽  
Resolution Data

Heavy-atom derivatization is one of the oldest techniques for obtaining phase information for protein crystals and, although it is no longer the first choice, it remains a useful technique for obtaining phases for unknown structures and for low-resolution data sets. It is also valuable for confirming the chain trace in low-resolution electron-density maps. This overview provides a summary of the technique and is aimed at first-time users of the method. It includes guidelines on when to use it, which heavy atoms are most likely to work, how to prepare heavy-atom solutions, how to derivatize crystals and how to determine whether a crystal is in fact a derivative.

scholarly journals Adverse event load, onset, and maximum grade: A novel method of reporting adverse events in cancer clinical trials

2020 ◽  
pp. 174077452095931
Author(s):  
Guilherme S Lopes ◽  
Christophe Tournigand ◽  
Curtis L Olswold ◽  
Romain Cohen ◽  
Emmanuelle Kempf ◽  
...  
Keyword(s):  
Adverse Event ◽  
Adverse Event Reporting ◽  
Data Sets ◽  
Event Data ◽  
Event Reporting ◽  
Adverse Event Data ◽  
Data Points ◽  
First Time ◽  
Reporting Method ◽  
Specific Adverse Event

Background Current adverse event reporting practices do not document longitudinal characteristics of adverse effects, and alternative methods are not easily interpretable and have not been employed by clinical trials. Introducing time parameters in the evaluation of safety that are comprehensive yet easily interpretable could allow for a better understanding of treatment quality. In this study, we developed and applied a novel adverse event reporting method based on longitudinal adverse event changes to aid describing, summarizing, and presenting adverse event profile. We termed it the “Adverse Event Load, Onset, and Maximum Grade” method. Methods We developed two adverse event summary metrics to complement the traditional maximum grade report. Onset time indicates the time period in which the maximum grade for a specific adverse event occurred and was defined as “early” (i.e. maximum grade happened for the first time before 6 weeks) or “late” (i.e. after the 6th week). Adverse event load indicates the overall severity of a specific adverse event over the entire treatment. Higher adverse event load indicates a worse overall experience. These metrics can be calculated for adverse events with different maximum grades, in treatments with planned changes (e.g. dosage changes), using data sets with different number of adverse event data points between treatments (e.g. treatments with longer cycle lengths may have less adverse event data points) and on data sets with different adverse event data availability (e.g. cycle basis and patient-outcome reports). We tested the utility of this method using individual patient data from two major backbone therapies (“Irinotecan” and “Oxaliplatin”) from the N9741 trial available in the Fondation ARCAD database ( fondationarcad.org ). We investigated profiles of diarrhea, neutropenia/leukopenia, and nausea/vomiting. Results Our method provided additional information compared to traditional adverse event reports. For example, for nausea/vomiting, while patients in Irinotecan had a higher risk of experiencing maximum grade 3–4 (15.6% vs 7.6%, respectively; p < 0.001), patients in both groups experienced similar severity over time (adverse effect load = 0.102 and 0.096, respectively; p = 0.26), suggesting that patients in Oxaliplatin experienced a lower-grade but more persistent nausea/vomiting. For neutropenia/leukopenia, more patients in Irinotecan experienced their maximum grade for the first time early in the treatment compared to patients in Oxaliplatin (67.9% vs 41.7%; p < 0.001), regardless of maximum grade. Longitudinal information can help compare treatments or guide clinicians on choosing appropriate interventions for low-grade but persistent adverse event or early adverse event onset. Conclusion We developed an adverse event reporting method that provides clinically relevant information about treatment toxicity by incorporating two longitudinal adverse event metrics to the traditional maximum grade approach. Future research should establish clinical benchmarks for metrics included in this adverse event reporting method.

scholarly journals Updated radio Σ - D relation for galactic supernova remnants - II

2019 ◽  
pp. 23-37 ◽  
Author(s):  
B. Vukotic ◽  
A. ciprijanovic ◽  
M.M. Vucetic ◽  
D. Onic ◽  
D. Urosevic
Keyword(s):  
Supernova Remnants ◽  
Surface Brightness ◽  
Small Diameter ◽  
Kernel Density ◽  
Fitting Procedure ◽  
Calibration Sample ◽  
Calibration Samples

In this paper we present the updated empirical radio surface- brightness-to-diameter (?-D) relation for Galactic supernova remnants (SNRs) calibrated using 110 SNRs with reliable distances. We apply orthogonal fitting procedure and kernel density smoothing in the ? ? D plane and compare the results with the latest theoretical ? - D relations derived from simulations of radio evolution of SNRs. We argue that the best agreement between the empirical and simulated ? ? D relations is achieved if the mixed-morphology SNRs and SNRs of both, low brightness and small diameter, are filtered out from the calibration sample. The distances to 5 newly discovered remnants and 27 new candidates for shell SNRs are estimated from our full and filtered calibration samples.

scholarly journals Characterizing EoR foregrounds: a study of the Lockman Hole region at 325 MHz

2020 ◽  
Vol 495 (4) ◽  
pp. 4071-4084
Author(s):  
Aishrila Mazumder ◽  
Arnab Chakraborty ◽  
Abhirup Datta ◽  
Samir Choudhuri ◽  
Nirupam Roy ◽  
...  
Keyword(s):  
Power Law ◽  
Galactic Plane ◽  
Low Frequency ◽  
Detailed Comparison ◽  
Data Sets ◽  
Diffuse Emission ◽  
Angular Power Spectrum ◽  
Power Law Index ◽  
First Time ◽  
Lockman Hole

ABSTRACT One of the key science goals for the most sensitive telescopes, both current and upcoming, is the detection of the redshifted 21-cm signal from the Cosmic Dawn and Epoch of Reionization. The success of detection relies on accurate foreground modelling for their removal from data sets. This paper presents the characterization of astrophysical sources in the Lockman Hole region. Using 325-MHz data obtained from the Giant Metrewave Radio Telescope, a 6° × 6° mosaiced map is produced with an rms reaching 50 μJy per beam. A source catalogue containing 6186 sources is created, and the Euclidean normalized differential source counts have been derived from it, consistent with previous observations as well as simulations. A detailed comparison of the source catalogue is also made with previous findings – at both lower and higher frequencies. The angular power spectrum (APS) of the diffuse Galactic synchrotron emission is determined for three different Galactic latitudes using the tapered gridded estimator. The values of the APS lie between ∼1 and ∼100 mK2. Fitting a power law of the form Aℓ−β gives values of A and β varying across the latitudes considered. This paper demonstrates, for the first time, the variation of the power-law index for diffuse emission at very high Galactic locations. It follows the same trend that is seen at locations near the Galactic plane, thus emphasizing the need for low-frequency observations for developing better models of the diffuse emission.

scholarly journals Study of the Galactic radio sources in the SCORPIO survey resolved by ATCA at 2.1 GHz

2019 ◽  
Author(s):  
A Ingallinera ◽  
G Umana ◽  
C Trigilio ◽  
R Norris ◽  
T M O Franzen ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Galactic Plane ◽  
Radio Sources ◽  
H Ii Regions ◽  
Extended Radio ◽  
Galactic Source ◽  
Extended Sources ◽  
Early Operations ◽  
First Time ◽  
Source Extraction

Abstract We present a catalogue of a large sample of extended radio sources in the SCORPIO field, observed and resolved by the Australia Telescope Compact Array. SCORPIO, a pathfinder project for addressing the early operations of the Australia SKA Pathfinder, is a survey of ∼5 square degrees between 1.4 and 3.1 GHz, centered at l = 343.5○, b = 0.75○ and with an angular resolution of about 10 arcsec. It is aimed at understanding the scientific and technical challenges to be faced by future Galactic surveys. With a mean sensitivity around $100\ \mu \mathrm{Jy\ beam}^{-1}$ and the possibility to recover angular scales at least up to 4 arcmin, we extracted 99 extended sources, 35 of them detected for the first time. Among the 64 known sources 55 had at least a tentative classification in literature. Studying the radio morphology and comparing the radio emission with infrared we propose as candidates 6 new H ii regions, 2 new planetary nebulae, 2 new luminous blue variable or Wolf–Rayet stars and 3 new supernova remnants. This study provides an overview of the potentiality of future radio surveys in terms of Galactic source extraction and characterization and a discussion on the difficulty to reduce and analyze interferometric data on the Galactic plane.

scholarly journals Radio polarization observations of large supernova remnants at λ6 cm

2013 ◽  
Vol 9 (S296) ◽  
pp. 202-209 ◽  
Author(s):  
J. L. Han ◽  
X. Y. Gao ◽  
X. H. Sun ◽  
W. Reich ◽  
L. Xiao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Spectral Index ◽  
Supernova Remnants ◽  
Galactic Plane ◽  
Measured Flux ◽  
Thermal Spectrum ◽  
Intrinsic Magnetic Field ◽  
Spectral Break ◽  
Index Maps ◽  
First Time

AbstractWe have observed 79 supernova remnants (SNRs) with the Urumqi 25 m telescope at λ6 cm during the Sino-German λ6 cm polarization survey of the Galactic plane. We measured flux densities of SNRs at λ6 cm, some of which are the first ever measured or the measurements at the highest frequency, so that we can determine or improve spectra of SNRs. Our observations have ruled out spectral breaks or spectral flattening that were suggested for a few SNRs, and confirmed the spectral break of S147. By combining our λ6 cm maps with λ11 cm and λ21 cm maps from the Effelsberg 100 m telescope, we calculated the spectral index maps of several large SNRs. For many remnants we obtained for the first time polarization images, which show the intrinsic magnetic field structures at λ6 cm. We disapproved three objects as being SNRs, OA184, G192.8−1.1 and G16.8−1.1, which show a thermal spectrum and no polarization. We have discovered two large supernova remnants, G178.2−4.2 and G25.1−2.3., in the survey maps.

scholarly journals DLR HySU—A Benchmark Dataset for Spectral Unmixing

2021 ◽  
Vol 13 (13) ◽  
pp. 2559
Author(s):  
Daniele Cerra ◽  
Miguel Pato ◽  
Kevin Alonso ◽  
Claas Köhler ◽  
Mathias Schneider ◽  
...  
Keyword(s):  
Spectral Unmixing ◽  
Benchmark Dataset ◽  
Data Sets ◽  
Endmember Extraction ◽  
Imaging Spectrometer ◽  
Hyperspectral Unmixing ◽  
Processing Step ◽  
German Aerospace ◽  
Spectrometer Data ◽  
First Time

Spectral unmixing represents both an application per se and a pre-processing step for several applications involving data acquired by imaging spectrometers. However, there is still a lack of publicly available reference data sets suitable for the validation and comparison of different spectral unmixing methods. In this paper, we introduce the DLR HyperSpectral Unmixing (DLR HySU) benchmark dataset, acquired over German Aerospace Center (DLR) premises in Oberpfaffenhofen. The dataset includes airborne hyperspectral and RGB imagery of targets of different materials and sizes, complemented by simultaneous ground-based reflectance measurements. The DLR HySU benchmark allows a separate assessment of all spectral unmixing main steps: dimensionality estimation, endmember extraction (with and without pure pixel assumption), and abundance estimation. Results obtained with traditional algorithms for each of these steps are reported. To the best of our knowledge, this is the first time that real imaging spectrometer data with accurately measured targets are made available for hyperspectral unmixing experiments. The DLR HySU benchmark dataset is openly available online and the community is welcome to use it for spectral unmixing and other applications.

scholarly journals ON GENERATING DIGITAL ELEVATION MODELS FROM LIDAR DATA – RESOLUTION VERSUS ACCURACY AND TOPOGRAPHIC WETNESS INDEX INDICES IN NORTHERN PEATLANDS

2012 ◽  
Vol 38 (2) ◽  
pp. 57-69 ◽  
Author(s):  
Abdulghani Hasan ◽  
Petter Pilesjö ◽  
Andreas Persson
Keyword(s):  
Large Scale ◽  
Drainage Area ◽  
Data Sets ◽  
Topographic Wetness Index ◽  
Absolute Deviation ◽  
Digital Elevation ◽  
Elevation Data ◽  
Scale Modelling ◽  
Data Points ◽  
Emission Modelling

Global change and GHG emission modelling are dependent on accurate wetness estimations for predictions of e.g. methane emissions. This study aims to quantify how the slope, drainage area and the TWI vary with the resolution of DEMs for a flat peatland area. Six DEMs with spatial resolutions from 0.5 to 90 m were interpolated with four different search radiuses. The relationship between accuracy of the DEM and the slope was tested. The LiDAR elevation data was divided into two data sets. The number of data points facilitated an evaluation dataset with data points not more than 10 mm away from the cell centre points in the interpolation dataset. The DEM was evaluated using a quantile-quantile test and the normalized median absolute deviation. It showed independence of the resolution when using the same search radius. The accuracy of the estimated elevation for different slopes was tested using the 0.5 meter DEM and it showed a higher deviation from evaluation data for steep areas. The slope estimations between resolutions showed differences with values that exceeded 50%. Drainage areas were tested for three resolutions, with coinciding evaluation points. The model ability to generate drainage area at each resolution was tested by pair wise comparison of three data subsets and showed differences of more than 50% in 25% of the evaluated points. The results show that consideration of DEM resolution is a necessity for the use of slope, drainage area and TWI data in large scale modelling.

scholarly journals Inter- and Intralaboratory Comparison of JC Polyomavirus Antibody Testing Using Two Different Virus-Like Particle-Based Assays

2014 ◽  
Vol 21 (11) ◽  
pp. 1581-1588 ◽  
Author(s):  
Piotr Kardas ◽  
Mohammadreza Sadeghi ◽  
Fabian H. Weissbach ◽  
Tingting Chen ◽  
Lea Hedman ◽  
...  
Keyword(s):  
Risk Stratification ◽  
Data Sets ◽  
Antibody Testing ◽  
Jc Polyomavirus ◽  
Virus Like Particle ◽  
Interlaboratory Variability ◽  
Increased Risk ◽  
Basic Protocol ◽  
Data Points ◽  
Reference Serum

ABSTRACTJC polyomavirus (JCPyV) can cause progressive multifocal leukoencephalopathy (PML), a debilitating, often fatal brain disease in immunocompromised patients. JCPyV-seropositive multiple sclerosis (MS) patients treated with natalizumab have a 2- to 10-fold increased risk of developing PML. Therefore, JCPyV serology has been recommended for PML risk stratification. However, different antibody tests may not be equivalent. To study intra- and interlaboratory variability, sera from 398 healthy blood donors were compared in 4 independent enzyme-linked immunoassay (ELISA) measurements generating >1,592 data points. Three data sets (Basel1, Basel2, and Basel3) used the same basic protocol but different JCPyV virus-like particle (VLP) preparations and introduced normalization to a reference serum. The data sets were also compared with an independent method using biotinylated VLPs (Helsinki1). VLP preadsorption reducing ≥35% activity was used to identify seropositive sera. The results indicated that Basel1, Basel2, Basel3, and Helsinki1 were similar regarding overall data distribution (P= 0.79) and seroprevalence (58.0, 54.5, 54.8, and 53.5%, respectively;P= 0.95). However, intra-assay intralaboratory comparison yielded 3.7% to 12% discordant results, most of which were close to the cutoff (0.080 < optical density [OD] < 0.250) according to Bland-Altman analysis. Introduction of normalization improved overall performance and reduced discordance. The interlaboratory interassay comparison between Basel3 and Helsinki1 revealed only 15 discordant results, 14 (93%) of which were close to the cutoff. Preadsorption identified specificities of 99.44% and 97.78% and sensitivities of 99.54% and 95.87% for Basel3 and Helsinki1, respectively. Thus, normalization to a preferably WHO-approved reference serum, duplicate testing, and preadsorption for samples around the cutoff may be necessary for reliable JCPyV serology and PML risk stratification.

Sign in / Sign up

Export Citation Format

Share Document