11,454 research outputs found
Monte Carlo Performance Studies of Candidate Sites for the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) is the next-generation gamma-ray
observatory with sensitivity in the energy range from 20 GeV to beyond 300 TeV.
CTA is proposed to consist of two arrays of 40-100 imaging atmospheric
Cherenkov telescopes, with one site located in each of the Northern and
Southern Hemispheres. The evaluation process for the candidate sites for CTA is
supported by detailed Monte Carlo simulations, which take different attributes
like site altitude and geomagnetic field configuration into account. In this
contribution we present the comparison of the sensitivity and performance of
the different CTA site candidates for the measurement of very-high energy gamma
rays.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Comparison of Fermi-LAT and CTA in the region between 10-100 GeV
The past decade has seen a dramatic improvement in the quality of data
available at both high (HE: 100 MeV to 100 GeV) and very high (VHE: 100 GeV to
100 TeV) gamma-ray energies. With three years of data from the Fermi Large Area
Telescope (LAT) and deep pointed observations with arrays of Cherenkov
telescope, continuous spectral coverage from 100 MeV to TeV exists for
the first time for the brightest gamma-ray sources. The Fermi-LAT is likely to
continue for several years, resulting in significant improvements in high
energy sensitivity. On the same timescale, the Cherenkov Telescope Array (CTA)
will be constructed providing unprecedented VHE capabilities. The optimisation
of CTA must take into account competition and complementarity with Fermi, in
particularly in the overlapping energy range 10100 GeV. Here we compare the
performance of Fermi-LAT and the current baseline CTA design for steady and
transient, point-like and extended sources.Comment: Accepted for Publication in Astroparticle Physic
The H.E.S.S. extragalactic sky
The H.E.S.S. Cherenkov telescope array, located on the southern hemisphere in
Namibia, studies very high energy (VHE; E>100 GeV) gamma-ray emission from
astrophysical objects. During its successful operations since 2002 more than 80
galactic and extra-galactic gamma-ray sources have been discovered. H.E.S.S.
devotes over 400 hours of observation time per year to the observation of
extra-galactic sources resulting in the discovery of several new sources,
mostly AGNs, and in exciting physics results e.g. the discovery of very rapid
variability during extreme flux outbursts of PKS 2155-304, stringent limits on
the density of the extragalactic background light (EBL) in the near-infrared
derived from the energy spectra of distant sources, or the discovery of
short-term variability in the VHE emission from the radio galaxy M 87. With the
recent launch of the Fermi satellite in 2008 new insights into the physics of
AGNs at GeV energies emerged, leading to the discovery of several new
extragalactic VHE sources. Multi-wavelength observations prove to be a powerful
tool to investigate the production mechanism for VHE emission in AGNs. Here,
new results from H.E.S.S. observations of extragalactic sources will be
presented and their implications for the physics of these sources will be
discussed.Comment: 8 pages, 6 figures, invited review talk, in the proceedings of the
"International Workshop on Beamed and Unbeamed Gamma-Rays from Galaxies"
11-15 April 2011, Lapland Hotel Olos, Muonio, Finland, Journal of Physics:
Conference Series Volume 355, 201
Adaptive Evolution of Conserved Noncoding Elements in Mammals
Conserved noncoding elements (CNCs) are an abundant feature of vertebrate genomes. Some CNCs have been shown to act as cis-regulatory modules, but the function of most CNCs remains unclear. To study the evolution of CNCs, we have developed a statistical method called the âshared rates testâ to identify CNCs that show significant variation in substitution rates across branches of a phylogenetic tree. We report an application of this method to alignments of 98,910 CNCs from the human, chimpanzee, dog, mouse, and rat genomes. We find that âŒ68% of CNCs evolve according to a null model where, for each CNC, a single parameter models the level of constraint acting throughout the phylogeny linking these five species. The remaining âŒ32% of CNCs show departures from the basic model including speed-ups and slow-downs on particular branches and occasionally multiple rate changes on different branches. We find that a subset of the significant CNCs have evolved significantly faster than the local neutral rate on a particular branch, providing strong evidence for adaptive evolution in these CNCs. The distribution of these signals on the phylogeny suggests that adaptive evolution of CNCs occurs in occasional short bursts of evolution. Our analyses suggest a large set of promising targets for future functional studies of adaptation
EU External Relations: Exclusive Competence Revisited
This Article will focus on the question of exclusive competence in the field of EU external relations, especially in the light of recent developments. After a brief discussion on the origins and development of exclusive competence, a distinction will be made between common commercial policy, which has traditionally been the most important area of an explicit âa prioriâ exclusive competence, and what is often called an implicit exclusive competence, which, as it is today based on some general criteria enshrined in TFEU Article 3(2), may be called âsuperveningâ exclusive competence. With regard to both categories, the main focus will be on recent developments, notably the impact of the Treaty of Lisbon, which introduced the TFEU and its Articles 2 and 3, as well as the case law of the European Court of Justice (âECJâ or the âCourtâ) following the entry into force of the Treaty of Lisbon, on December 1, 2009
Das euebm-Projekt an der UniversitÀtsklinik Frankfurt am Main
Hintergrund: Die Notwendigkeit der Etablierung der Anwendung von Evidenzbasierter Medizin (EbM) in den klinischen Alltag sowie die Sicherung der europaweiten Qualifikation in EbM ist seit geraumer Zeit vielfĂ€ltig diskutiert worden. Gefördert durch das "Leonardo da Vinci"- Berufsbildungsprogramm der EuropĂ€ischen Union hat das euebm-Projekt zum Ziel, durch ein europaweit einheitliches integriertes Basiscurriculum fĂŒr evidenzbasierte Medizin eine bessere Verzahnung zwischen dem Erlernen der EbM-Techniken und der eigenen Patientenversorgung zu erreichen. An der UniversitĂ€tsklinik Frankfurt am Main wird ab dem 01.01.2009 das euebm-Projekt in den klinischen Alltag integriert werden. Die Zielgruppe dieses Projektes bilden alle AssistenzĂ€rzte jeglicher Fachrichtungen im 1. Weiterbildungsjahr. Durch einen online-basierten Kurs wird den Interessenten die Möglichkeit geboten, an den einzelnen Lehrmodulen teilzunehmen.
Methoden: Es werden alle AssistenzĂ€rzte im 1. Weiterbildungsjahr in einem individualisierten Schreiben zur Teilnahme an dem Projekt aufgefordert. Nach der elektronischen Anmeldung werden die Teilnehmer prĂ€test-Evaluationsbogen mit inhaltlichen EbM-Fragen beantworten. Danach durchlaufen die Teilnehmer ein EbM-Lernprogramm, bestehend aus 5 Modulen. Jedes Modul wird durch eine Lernerfolgskontrolle abgeschlossen. AbschlieĂend wird eine Gesamtlernkontrolle von jedem Teilnehmer abverlangt. Am Ende des online-Kurses werden die Teilnehmer ebenfalls einen mehrteiligen subjektiven Evaluationsbogen beantworten. Um einen lĂ€ngerfristigen Lerneffekt messen zu können, werden 6 Monate bzw. 1 Jahr nach dem erfolgreichen Abschluss die Teilnehmer erneut einen objektiven inhaltlichen Evaluationsbogen bearbeiten.
Ergebnisse: Im Rahmen der 10. Jahrestagung des DNEbM im MÀrz 2009 können voraussichtlich Zwischenergebnisse der objektiven (prÀinterventionell vs. postinterventionell) und subjektiven Evaluationen veröffentlicht werden. Zudem wird derzeit die Erstellung einer statistischen Auswertung der Zugriffszahlen auf die verschiedenen medizinischen Online-Datenbanken und Suchmaschinen (prÀ- und postinterventionell) aufgebaut.
Schlussfolgerung/Implikation: Mit Hilfe der curricular vermittelten Lehrinhalte und Techniken sollen Ărzte in die Lage versetzt werden, EbM praxisnah fĂŒr und mit ihren Patienten umzusetzen. In der konkreten Anwendung von EbM an ihren individuellen Patienten können Ărzte möglicherweise erfahren, dass die Integration von EbM in den klinischen Alltag ihr Spektrum an Beratungs- und Behandlungsmöglichkeiten erweitert
Improving the value of public RNA-seq expression data by phenotype prediction.
Publicly available genomic data are a valuable resource for studying normal human variation and disease, but these data are often not well labeled or annotated. The lack of phenotype information for public genomic data severely limits their utility for addressing targeted biological questions. We develop an in silico phenotyping approach for predicting critical missing annotation directly from genomic measurements using well-annotated genomic and phenotypic data produced by consortia like TCGA and GTEx as training data. We apply in silico phenotyping to a set of 70 000 RNA-seq samples we recently processed on a common pipeline as part of the recount2 project. We use gene expression data to build and evaluate predictors for both biological phenotypes (sex, tissue, sample source) and experimental conditions (sequencing strategy). We demonstrate how these predictions can be used to study cross-sample properties of public genomic data, select genomic projects with specific characteristics, and perform downstream analyses using predicted phenotypes. The methods to perform phenotype prediction are available in the phenopredict R package and the predictions for recount2 are available from the recount R package. With data and phenotype information available for 70,000 human samples, expression data is available for use on a scale that was not previously feasible
Dr. Yang Zhong: an explorer on the road forever
On the morning of September 25th 2017, grievous news spread from the remote Ordos region of Inner Mongolia to Fudan University campus in Shanghai. Professor Yang Zhong, a famous botanist and the Dean of Fudan Universityâs graduate school, passed away in a tragic car accident while on a business trip
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PacBio assembly of a Plasmodium knowlesi genome sequence with Hi-C correction and manual annotation of the SICAvar gene family.
Plasmodium knowlesi has risen in importance as a zoonotic parasite that has been causing regular episodes of malaria throughout South East Asia. The P. knowlesi genome sequence generated in 2008 highlighted and confirmed many similarities and differences in Plasmodium species, including a global view of several multigene families, such as the large SICAvar multigene family encoding the variant antigens known as the schizont-infected cell agglutination proteins. However, repetitive DNA sequences are the bane of any genome project, and this and other Plasmodium genome projects have not been immune to the gaps, rearrangements and other pitfalls created by these genomic features. Today, long-read PacBio and chromatin conformation technologies are overcoming such obstacles. Here, based on the use of these technologies, we present a highly refined de novo P. knowlesi genome sequence of the Pk1(A+) clone. This sequence and annotation, referred to as the 'MaHPIC Pk genome sequence', includes manual annotation of the SICAvar gene family with 136 full-length members categorized as type I or II. This sequence provides a framework that will permit a better understanding of the SICAvar repertoire, selective pressures acting on this gene family and mechanisms of antigenic variation in this species and other pathogens
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