GK Per (Nova Persei 1901): HST Imagery and Spectroscopy of the Ejecta, and First Spectrum of the Jet-Like Feature

We have imaged the ejecta of GK Persei (Nova Persei 1901 A.D.) with the Hubble Space Telescope (HST), revealing hundreds of cometary-like structures. One or both ends of the structures often show a brightness enhancement relative to the structures' middle sections, but there is no simple regularity to their morphologies (in contrast with the Helix nebula). Some of the structures' morphologies suggest the presence of slow-moving or stationary material with which the ejecta is colliding, while others suggest shaping from a wind emanating from GK Per itself. A detailed expansion map of the nova's ejecta was created by comparing HST images taken in successive years. WFPC2 narrowband images and STIS spectra demonstrate that the physical conditions in the ejecta vary strongly on spatial scales much smaller than those of the ejecta. Directly measuring accurate densities and compositions, and hence masses of this and other nova shells, will demand data at least as resolved spatially as those presented here. The filling factor the ejecta is < 1%, and the nova ejecta mass must be less than 10^{-4} \Msun. A few of the nebulosities vary in brightness by up to a factor of two on timescales of one year. Finally, we present the deepest images yet obtained of a jet-like feature outside the main body of GK Per nebulosity, and the first spectrum of that feature. Dominated by strong, narrow emission lines of [NII], [OII], [OIII], and [SII], this feature is probably a shock due to ejected material running into stationary ISM, slowly moving ejecta from a previous nova episode, or circum-binary matter present before 1901. An upper limit to the mass of the jet is of order a few times 10^{-6} \Msun. The jet might be an important, or even dominant mass sink from the binary system. The jet's faintness suggests that similar features could easily have been missed in other cataclysmic binaries.Comment: 43 pages, 17 figure

In-pandemic development of an application ontology for COVID-19 surveillance in a primary care sentinel network

Background: Creating an ontology for coronavirus disease 2019 (COVID-19) surveillance should help ensure transparency and consistency. Ontologies formalise conceptualisations at either domain or application level. Application ontologies cross domains and are specified through testable use cases. Our use case was extension of the role of the Oxford Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) to monitor the current pandemic and become an in-pandemic research platform. Objective: To develop an application ontology for COVID-19 which can be deployed across the various use case domains of the Oxford- RCGP RSC research and surveillance activities. Methods: We described our domain-specific use case. The actor was the RCGP RSC sentinel network; the system the course of the COVID-19 pandemic; the outcomes the spread and effect of mitigation measures. We used our established three-step method to develop the ontology, separating ontological concept development from code mapping and data extract validation. We developed a coding system–independent COVID-19 case identification algorithm. As there were no gold standard pandemic surveillance ontologies, we conducted a rapid Delphi consensus exercise through the International Medical Informatics Association (IMIA) Primary Health Care Informatics working group and extended networks. Results: Our use case domains included primary care, public health, virology, clinical research and clinical informatics. Our ontology supported: (1) Case identification, microbiological sampling and health outcomes at both an individual practice and national level; (2) Feedback through a dashboard; (3) A national observatory, (4) Regular updates for Public Health England, and (5) Transformation of the sentinel network to be a trial platform. We have identified a total of 8,627 people with a definite COVID-19 status, 4,240 with probable, and 59,147 people with possible COVID-19, within the RCGP RSC network (N=5,056,075). Conclusions: The underpinning structure of our ontological approach has coped with multiple clinical coding challenges. At a time when there is uncertainty about international comparisons, clarity about the basis on which case definitions and outcomes are made from routine data is essential

Nicotine Pretreatment Increases Dysphoric Effects of Alcohol in Luteal-Phase Female Volunteers

The present report shows that nicotine enhances some of alcohol’s positive and negative effects in women and that these effects are most pronounced during the luteal phase of the menstrual cycle. Ten low progesterone and 10 high progesterone/luteal-phase women received nicotine patch pretreatments (placebo or 21 mg) 3 hours before an alcohol challenge (0.4 g/kg). Subjective effects were recorded on mood adjective scales and the Addiction Research Center Inventory (ARCI). Heart rate and skin temperature were recorded. Luteal-phase women reported peak positive (e.g. “stimulated”) and peak negative effects (e.g. “clumsy”, “dizzy”) almost twice as great as low progesterone women

The human DEK oncogene regulates DNA damage response signaling and repair

The human DEK gene is frequently overexpressed and sometimes amplified in human cancer. Consistent with oncogenic functions, Dek knockout mice are partially resistant to chemically induced papilloma formation. Additionally, DEK knockdown in vitro sensitizes cancer cells to DNA damaging agents and induces cell death via p53-dependent and -independent mechanisms. Here we report that DEK is important for DNA double-strand break repair. DEK depletion in human cancer cell lines and xenografts was sufficient to induce a DNA damage response as assessed by detection of γH2AX and FANCD2. Phosphorylation of H2AX was accompanied by contrasting activation and suppression, respectively, of the ATM and DNA-PK pathways. Similar DNA damage responses were observed in primary Dek knockout mouse embryonic fibroblasts (MEFs), along with increased levels of DNA damage and exaggerated induction of senescence in response to genotoxic stress. Importantly, Dek knockout MEFs exhibited distinct defects in non-homologous end joining (NHEJ) when compared to their wild-type counterparts. Taken together, the data demonstrate new molecular links between DEK and DNA damage response signaling pathways, and suggest that DEK contributes to DNA repair

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements