3,233 research outputs found
On the eve of the 100th anniversary of IAU Commission 19/A2 “Rotation of the Earth”
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.IAU Commission 19 began in 1919 with the birth of the IAU at the Brussels Conference, where Standing Committee 19 on Latitude Variations was established as one of 32 standing committees. At the first IAU General Assembly in 1922, Standing Committee 19 became Commission 19 “Variation of Latitude”. In the beginning, the main topic of the Commission was the investigation of polar motion. Later, its activities included observations and theory of Earth rotation and connections between Earth orientation variations and geophysical phenomena. As a result, in 1964 at the XII IAU General Assembly, the Commission was renamed “Rotation of the Earth”. The investigation of Earth orientation variations is primarily based on observations of natural and artificial celestial objects. Therefore, maintenance of the international terrestrial and celestial reference frames, as well as the coordinate transformation between the frames and the improvement of the model of precession/nutation, have always been among the primary Commission topics. In 1987, the IAU through Commissions 19 and 31 “Time” established, jointly with the International Union of Geodesy and Geophysics, what is now known as the International Earth Rotation and Reference Systems Service. Commission 19 continued to work to develop methods to improve the accuracy and understanding of Earth orientation variations and related reference systems and frames as well as theoretical studies of Earth rotation. In 2015, Commission 19 was renewed as Commission A2 “Rotation of the Earth” continuing Commission 19’s functions and linking the astronomical community to other scientific organizations such as the International Association of Geodesy, International VLBI Service for Geodesy and Astrometry, International GNSS Service, International Laser Ranging Service and International DORIS Service. During its entire history, IAU Commission 19/A2 has always worked in close cooperation with these and other related services to improve the accuracy and consistency of the Earth orientation parameters and celestial and terrestrial reference frames
Assessment of providers' referral decisions in Rural Burkina Faso: a retrospective analysis of medical records
Differences in duration of untreated psychosis for racial and ethnic minority groups with first-episode psychosis: an updated systematic review and meta-analysis.
PURPOSE: Ethnic minority groups with early psychosis may have longer treatment delays, potentially leading to poorer outcomes. We updated a previous systematic review of the literature on racial and ethnic differences in duration of untreated psychosis (DUP) among people with first-episode psychosis.
RESULTS: Six of 17 studies described significant differences across aggregated racial groups; however, the pooled estimates did not show differences across groups. Additional data from this update allowed for disaggregated analyses, finding that Black-African groups have a shorter DUP, whereas Black-Caribbean groups have longer DUP, relative to White groups.
CONCLUSIONS: These findings highlight the importance of in-depth research on disaggregated ethnic groups to inform targeted early intervention strategies for minority populations
ChemSpectra: a web-based spectra editor for analytical data
ChemSpectra, a web-based software to visualize and analyze spectroscopic data, integrating solutions for infrared spectroscopy (IR), mass spectrometry (MS), and one-dimensional H and C NMR (proton and carbon nuclear magnetic resonance) spectroscopy, is described. ChemSpectra serves as web-based tool for the analysis of the most often used types of one-dimensional spectroscopic data in synthetic (organic) chemistry research. It was developed to support in particular processes for the use of open file formats which enable the work according to the FAIR data principles. The software can deal with the open file formats JCAMP-DX (IR, MS, NMR) and mzML (MS) proposing these data file types to gain interoperable data. ChemSpectra can be extended to read also other formats as exemplified by selected proprietary mass spectrometry data files of type RAW and NMR spectra files of type FID. The JavaScript-based editor can be integrated with other software, as demonstrated by integration into the Chemotion electronic lab notebook (ELN) and Chemotion repository, demonstrating the implementation into a digital work environment that offers additional functionality and sustainable research data management options. ChemSpectra supports different functions for working with spectroscopic data such as zoom functions, peak picking and automatic peak detection according to a default or manually defined threshold. NMR specific functions include the definition of a reference signal, the integration of signals, coupling constant calculation and multiplicity assignment. Embedded into a web application such as an ELN or a repository, the editor can also be used to generate an association of spectra to a sample and a file management. The file management supports the storage of the original spectra along with the last edited version and an automatically generated image of the spectra in png format. To maximize the benefit of the spectra editor for e.g. ELN users, an automated procedure for the transfer of the detected or manually chosen signals to the ELN was implemented. ChemSpectra is released under the AGPL license to encourage its re-use and further developments by the community
ChemScanner: extraction and re-use(ability) of chemical information from common scientific documents containing ChemDraw files
We developed ChemScanner, a software that can be used for the extraction of chemical information from ChemDraw binary (CDX) or ChemDraw XML-based (CDXML) files and to retrieve the ChemDraw scheme from DOC, DOCX or XML documents. This can facilitate the reuse of chemical information embedded into diverse documents used as standard storage and communication instrument in chemical sciences (e.g. for student’s theses, PhD theses, or publications). The extracted information is processed to reactions, molecules, as well as additional text and values and can be accessed via the ChemScanner UI. ChemScanner supports the export to Excel and CML, the direct import of the extracted data to the Open Source ELN Chemotion or the use via “copy and paste” of selected information. The software was designed with a focus on the processing of documents with embedded molecular structure information as CDX or CDXML as these are the most common file formats for chemical drawings. The project aims to support the chemists in their efforts to re-use chemistry research data by providing them missing tools for an automated assembly of reaction data
Novel personalized pathway-based metabolomics models reveal key metabolic pathways for breast cancer diagnosis
Comparison of logistic regression, SVM and random forest performance in the plasma training data set. Table S2. Pathway significance and relative log fold changes in our metabolomics data and TCGA breast cancer RNA-Seq data. Table S3. Detected metabolites and their differential test results among the two models. a All-stage diagnosis model. b Early-stage diagnosis model. Table S4. Single-variate logistic analysis of metabolites or pathways selected as features in the metabolite-based or pathway-based early-stage diagnosis model. Table S5. Comparison of pathway features in the full-size (101 input pathways) and half-size (51 input pathways) pathway-based early-stage diagnosis models. (DOCX 34 kb
Segmenting Lecture Videos by Topic: From Manual to Automated Methods
More and more universities and corporations are starting to provide videotaped lectures online for knowledge sharing and learning. Segmenting lecture videos into short clips by topic can extract the hidden information structure of the videos and facilitate information searching and learning. Manual segmentation has high accuracy rates but is very labor intensive. In order to develop a high performance automated segmentation method for lecture videos, we conducted a case study to learn the segmentation process of humans and the effective segmentation features used in the process. Based on the findings from the case study, we designed an automated segmentation approach with two phases: initial segmentation and segmentation refinement. The approach combines segmentation features from three information sources of video (speech text transcript, audio and video) and makes use of various knowledge sources such as world knowledge and domain knowledge. Our preliminary results show that the proposed two-phase approach is promising
Gamma-Ray Bursts in Circumstellar Shells: A Possible Explanation for Flares
It is now generally accepted that long-duration gamma ray bursts (GRBs) are
due to the collapse of massive rotating stars. The precise collapse process
itself, however, is not yet fully understood. Strong winds, outbursts, and
intense ionizing UV radiation from single stars or strongly interacting
binaries are expected to destroy the molecular cloud cores that give birth to
them and create highly complex circumburst environments for the explosion. Such
environments might imprint features on GRB light curves that uniquely identify
the nature of the progenitor and its collapse. We have performed numerical
simulations of realistic environments for a variety of long-duration GRB
progenitors with ZEUS-MP, and have developed an analytical method for
calculating GRB light curves in these profiles. Though a full,
three-dimensional, relativistic magnetohydrodynamical computational model is
required to precisely describe the light curve from a GRB in complex
environments, our method can provide a qualitative understanding of these
phenomena. We find that, in the context of the standard afterglow model,
massive shells around GRBs produce strong signatures in their light curves, and
that this can distinguish them from those occurring in uniform media or steady
winds. These features can constrain the mass of the shell and the properties of
the wind before and after the ejection. Moreover, the interaction of the GRB
with the circumburst shell is seen to produce features that are consistent with
observed X-ray flares that are often attributed to delayed energy injection by
the central engine. Our algorithm for computing light curves is also applicable
to GRBs in a variety of environments such as those in high-redshift
cosmological halos or protogalaxies, both of which will soon be targets of
future surveys such as JANUS or Lobster.Comment: 12 pages, 5 figures, Accepted by Ap
HYR1-Mediated Detoxification of Reactive Oxygen Species Is Required for Full Virulence in the Rice Blast Fungus
During plant-pathogen interactions, the plant may mount several types of defense
responses to either block the pathogen completely or ameliorate the amount of
disease. Such responses include release of reactive oxygen species (ROS) to
attack the pathogen, as well as formation of cell wall appositions (CWAs) to
physically block pathogen penetration. A successful pathogen will likely have
its own ROS detoxification mechanisms to cope with this inhospitable
environment. Here, we report one such candidate mechanism in the rice blast
fungus, Magnaporthe oryzae, governed by a gene we refer to as
MoHYR1. This gene (MGG_07460) encodes a glutathione
peroxidase (GSHPx) domain, and its homologue in yeast was reported to
specifically detoxify phospholipid peroxides. To characterize this gene in
M. oryzae, we generated a deletion
mutantΔhyr1 which showed growth inhibition with
increased amounts of hydrogen peroxide (H2O2). Moreover,
we observed that the fungal mutants had a decreased ability to tolerate ROS
generated by a susceptible plant, including ROS found associated with CWAs.
Ultimately, this resulted in significantly smaller lesion sizes on both barley
and rice. In order to determine how this gene interacts with other (ROS)
scavenging-related genes in M. oryzae, we compared expression
levels of ten genes in mutant versus wild type with and without
H2O2. Our results indicated that the
HYR1 gene was important for allowing the fungus to tolerate
H2O2
in vitro and in planta and that this ability
was directly related to fungal virulence
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