104 research outputs found

    Faint Infrared Flares from the Microquasar GRS 1915+105

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    We present simultaneous infrared and X-ray observations of the Galactic microquasar GRS 1915+105 using the Palomar 5-m telescope and Rossi X-ray Timing Explorer on July 10, 1998 UT. Over the course of 5 hours, we observed 6 faint infrared (IR) flares with peak amplitudes of 0.30.6\sim 0.3-0.6 mJy and durations of 500600\sim 500-600 seconds. These flares are associated with X-ray soft-dip/soft-flare cycles, as opposed to the brighter IR flares associated with X-ray hard-dip/soft-flare cycles seen in August 1997 by Eikenberry et al. (1998). Interestingly, the IR flares begin {\it before} the X-ray oscillations, implying an ``outside-in'' origin of the IR/X-ray cycle. We also show that the quasi-steady IR excess in August 1997 is due to the pile-up of similar faint flares. We discuss the implications of this flaring behavior for understanding jet formation in microquasars.Comment: 10 pages, 4 figures Accepted for publication in ApJ Letter

    Enhancing Bowel Cancer Surgery Recovery through Information Design: The impact of combining design and cognitive principles with user-centered research methods, on patient understanding of surgery recovery information

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    Bowel surgery is the most common treatment for numerous bowel diseases Including cancer. The provision of Information before and after bowel surgery Is an Important element of recovery. Pre-operative education assists In the psychological preparation for surgery, which has been shown to have a positive Impact on patient satisfaction, pain management, and the duration of hospital stay. Traditionally, Information Is provided before surgery and delivered In text heavy written format, which presents a number of challenges, such as patients feeling overwhelmed, especially when diagnoses of cancer and plans for major surgery are discussed concurrently. Previous evidence also shows patients desire to be pro-actively Involved In their recovery. Unfortunately, the development of new education Interventions uncommonly Involves patients and other Information specialists In their design. To tackle this problem, a mixed-methods user-centered design approach was conducted to redesign an existing patient Information booklet In order to meet patient needs and Improve communication among patients and medical staff. For example, among other methods, a 'within co-design' approach was used to Identify stakeholder needs. Several usability tests and Iterations were conducted throughout the design development to create a more visualized design format that follows research-based cognitive and design principles. Empirical testing was then conducted to evaluate and validate the final booklet design, collecting both qualitative and quantitative data. Results show significant differences In performance and users' preference between text dense Information and a combination of text and visualized Information. This In-depth research focusing on the booklet was then followed by the development of companion outputs (website and environmental Infographics) through the same mixed-methods user-centered design approach. All In all, this study provides significant evidence and Important guidelines on how to effectively communicate bowel surgery recovery Information to patients, In order to Increase their understanding and active role In their recovery, as well as minimize their uncertainties and anxiety. Although focusing on a specific scenario, these findings are also widely applicable to many forms of healthcare Information

    Time-of-flight and activation experiments on 147Pm and 171Tm for astrophysics

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    The neutron capture cross section of several key unstable isotopes acting as branching points in the s-process are crucial for stellar nucleosynthesis studies, but they are very challenging to measure due to the difficult production of sufficient sample material, the high activity of the resulting samples, and the actual (n,γ) measurement, for which high neutron fluxes and effective background rejection capabilities are required. As part of a new program to measure some of these important branching points, radioactive targets of 147Pm and 171Tm have been produced by irradiation of stable isotopes at the ILL high flux reactor. Neutron capture on 146Nd and 170Er at the reactor was followed by beta decay and the resulting matrix was purified via radiochemical separation at PSI. The radioactive targets have been used for time-of-flight measurements at the CERN n-TOF facility using the 19 and 185 m beam lines during 2014 and 2015. The capture cascades were detected using a set of four C6D6 scintillators, allowing to observe the associated neutron capture resonances. The results presented in this work are the first ever determination of the resonance capture cross section of 147Pm and 171Tm. Activation experiments on the same 147Pm and 171Tm targets with a high-intensity 30 keV quasi-Maxwellian flux of neutrons will be performed using the SARAF accelerator and the Liquid-Lithium Target (LiLiT) in order to extract the corresponding Maxwellian Average Cross Section (MACS). The status of these experiments and preliminary results will be presented and discussed as well

    New measurement of the 242Pu(n,γ) cross section at n-TOF-EAR1 for MOX fuels : Preliminary results in the RRR

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    The spent fuel of current nuclear reactors contains fissile plutonium isotopes that can be combined with 238U to make mixed oxide (MOX) fuel. In this way the Pu from spent fuel is used in a new reactor cycle, contributing to the long-term sustainability of nuclear energy. The use of MOX fuels in thermal and fast reactors requires accurate capture and fission cross sections. For the particular case of 242Pu, the previous neutron capture cross section measurements were made in the 70's, providing an uncertainty of about 35% in the keV region. In this context, the Nuclear Energy Agency recommends in its "High Priority Request List" and its report WPEC-26 that the capture cross section of 242Pu should be measured with an accuracy of at least 7-12% in the neutron energy range between 500 eV and 500 keV. This work presents a brief description of the measurement performed at n-TOF-EAR1, the data reduction process and the first ToF capture measurement on this isotope in the last 40 years, providing preliminary individual resonance parameters beyond the current energy limits in the evaluations, as well as a preliminary set of average resonance parameters

    Characterization of the n-TOF EAR-2 neutron beam

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    The experimental area 2 (EAR-2) at CERNs neutron time-of-flight facility (n-TOF), which is operational since 2014, is designed and built as a short-distance complement to the experimental area 1 (EAR-1). The Parallel Plate Avalanche Counter (PPAC) monitor experiment was performed to characterize the beam prole and the shape of the neutron 'ux at EAR-2. The prompt γ-flash which is used for calibrating the time-of-flight at EAR-1 is not seen by PPAC at EAR-2, shedding light on the physical origin of this γ-flash

    The measurement programme at the neutron time-of-flight facility n-TOF at CERN

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    Neutron-induced reaction cross sections are important for a wide variety of research fields ranging from the study of nuclear level densities, nucleosynthesis to applications of nuclear technology like design, and criticality and safety assessment of existing and future nuclear reactors, radiation dosimetry, medical applications, nuclear waste transmutation, accelerator-driven systems and fuel cycle investigations. Simulations and calculations of nuclear technology applications largely rely on evaluated nuclear data libraries. The evaluations in these libraries are based both on experimental data and theoretical models. CERN's neutron time-of-flight facility n-TOF has produced a considerable amount of experimental data since it has become fully operational with the start of its scientific measurement programme in 2001. While for a long period a single measurement station (EAR1) located at 185 m from the neutron production target was available, the construction of a second beam line at 20 m (EAR2) in 2014 has substantially increased the measurement capabilities of the facility. An outline of the experimental nuclear data activities at n-TOF will be presented

    Active Galactic Nuclei at the Crossroads of Astrophysics

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    Over the last five decades, AGN studies have produced a number of spectacular examples of synergies and multifaceted approaches in astrophysics. The field of AGN research now spans the entire spectral range and covers more than twelve orders of magnitude in the spatial and temporal domains. The next generation of astrophysical facilities will open up new possibilities for AGN studies, especially in the areas of high-resolution and high-fidelity imaging and spectroscopy of nuclear regions in the X-ray, optical, and radio bands. These studies will address in detail a number of critical issues in AGN research such as processes in the immediate vicinity of supermassive black holes, physical conditions of broad-line and narrow-line regions, formation and evolution of accretion disks and relativistic outflows, and the connection between nuclear activity and galaxy evolution.Comment: 16 pages, 5 figures; review contribution; "Exploring the Cosmic Frontier: Astrophysical Instruments for the 21st Century", ESO Astrophysical Symposia Serie

    Fitting the integrated Spectral Energy Distributions of Galaxies

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    Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details ofdust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (sedfitting.org), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics & Space Scienc

    Improving recovery after bowel cancer surgery: mixed methods feasibility study of a co-produced information intervention (Recover Together)

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    Aim Recovery after surgery for colorectal cancer is a complex process, involving numerous physiological, emotional, social and economic challenges. Good information is a key factor for enabling patients to recover well, but there is a paucity of evidence to guide how this should be done. A new information intervention (Recover Together) comprising a booklet, an online video and an inpatient goal board has been developed. This study explores its feasibility, as well as the feasibility of key study methods, during its first use in the United Kingdom National Health Service (NHS). Methods This is a mixed methods, multi-centre, feasibility study of a complex intervention. A total of 105 participants undergoing oncological colorectal surgery will be recruited across three to four study sites in the UK. Participants will receive each component of the Recover Together intervention at defined timepoints before and during hospital admission. A series of patient-centred outcome instruments will be administered in hospital and during follow-up at 30 days and 6 months. Outcomes of feasibility will comprise the time taken to establish the intervention at participating sites, assessments of intervention fidelity and acceptability, as well as return rates of key clinical outcome instruments. The mixed methods design will comprise interviews and focus groups with patients and health professionals, non-participant observation in ward areas and clinics, user-specific video analytics and daily photographs of the goal boards. Discussion The findings of this study will provide a feasibility assessment of the Recover Together intervention when used for the first time in NHS practice. If shown to be feasible, this will guide the development of a future definitive study to explore the clinical and cost effectiveness of the Recover Together intervention to improve recovery after surgery. Clinical Trials Registration ISRCTN62430915
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