Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

[How much does research and development of a drug cost? A call for more transparency].

The cost of research and development (R&D) for a new medicine is an essential element in the debate about fair prices. In a recent study, we estimated R&D costs at an average of around 1.1 billion euro per drug; that is a lot of money, but more than 50% lower than the usual estimate of 2.4 billion euro. There is a need for more transparency about R&D costs, so that proposed prices for medicines can be better assessed on their fairness.status: Published onlin

Granularity effects in high-brightness electron beams

Electron sources based on laser-cooling and trapping techniques are a relatively new reality in the field of charge particle accelerators. The dynamics of these sources are governed by stochastic effects, and not by the usually dominant space-charge forces. As the high-brightness field moves towards increasingly higher brightness, these stochastic effects will play an increasingly important role. In this presentation I will discuss the physics of these granularity effects and show their effect using molecular dynamics simulations with the GPT code where we track each and every particle in realistic fields and including all pair-wise interactions

Two step photo-ionization of a laser cooled and compressed thermal atomic beam for use in a focused ion beam

Photo-ionization is applied to a laser cooled and compressed atomic rubidium\u3cbr/\u3ebeam in order to generate a high brightness ion beam. When focused, this ion beam can be used to image and edit integrated circuits at the nano-scale which is important for the ongoing reduction of feature sizes in the semiconductor industry. Experiments have shown that an atomic beam brightness in excess of 106 A/(m2 sr eV) can be achieved with a flux equivalent to 500 pA in a compact magneto-optical compressor which should be sufficient to generate ion spots of 1 nm. Currently, photo-ionization experiments are being carried out that aim at ionizing the majority of the atoms within a small longitudinal\u3cbr/\u3erange in order to minimize the longitudinal energy spread. The two step ionization setup uses a tightly focused excitation laser beam and a powerful blue laser coupled to a build-up-cavity