A Bayesian Approach to the Detection Problem in Gravitational Wave Astronomy

The analysis of data from gravitational wave detectors can be divided into three phases: search, characterization, and evaluation. The evaluation of the detection - determining whether a candidate event is astrophysical in origin or some artifact created by instrument noise - is a crucial step in the analysis. The on-going analyses of data from ground based detectors employ a frequentist approach to the detection problem. A detection statistic is chosen, for which background levels and detection efficiencies are estimated from Monte Carlo studies. This approach frames the detection problem in terms of an infinite collection of trials, with the actual measurement corresponding to some realization of this hypothetical set. Here we explore an alternative, Bayesian approach to the detection problem, that considers prior information and the actual data in hand. Our particular focus is on the computational techniques used to implement the Bayesian analysis. We find that the Parallel Tempered Markov Chain Monte Carlo (PTMCMC) algorithm is able to address all three phases of the anaylsis in a coherent framework. The signals are found by locating the posterior modes, the model parameters are characterized by mapping out the joint posterior distribution, and finally, the model evidence is computed by thermodynamic integration. As a demonstration, we consider the detection problem of selecting between models describing the data as instrument noise, or instrument noise plus the signal from a single compact galactic binary. The evidence ratios, or Bayes factors, computed by the PTMCMC algorithm are found to be in close agreement with those computed using a Reversible Jump Markov Chain Monte Carlo algorithm.Comment: 19 pages, 12 figures, revised to address referee's comment

Lack of effect of lowering LDL cholesterol on cancer: meta-analysis of individual data from 175,000 people in 27 randomised trials of statin therapy

<p>Background: Statin therapy reduces the risk of occlusive vascular events, but uncertainty remains about potential effects on cancer. We sought to provide a detailed assessment of any effects on cancer of lowering LDL cholesterol (LDL-C) with a statin using individual patient records from 175,000 patients in 27 large-scale statin trials.</p> <p>Methods and Findings: Individual records of 134,537 participants in 22 randomised trials of statin versus control (median duration 4.8 years) and 39,612 participants in 5 trials of more intensive versus less intensive statin therapy (median duration 5.1 years) were obtained. Reducing LDL-C with a statin for about 5 years had no effect on newly diagnosed cancer or on death from such cancers in either the trials of statin versus control (cancer incidence: 3755 [1.4% per year [py]] versus 3738 [1.4% py], RR 1.00 [95% CI 0.96-1.05]; cancer mortality: 1365 [0.5% py] versus 1358 [0.5% py], RR 1.00 [95% CI 0.93–1.08]) or in the trials of more versus less statin (cancer incidence: 1466 [1.6% py] vs 1472 [1.6% py], RR 1.00 [95% CI 0.93–1.07]; cancer mortality: 447 [0.5% py] versus 481 [0.5% py], RR 0.93 [95% CI 0.82–1.06]). Moreover, there was no evidence of any effect of reducing LDL-C with statin therapy on cancer incidence or mortality at any of 23 individual categories of sites, with increasing years of treatment, for any individual statin, or in any given subgroup. In particular, among individuals with low baseline LDL-C (<2 mmol/L), there was no evidence that further LDL-C reduction (from about 1.7 to 1.3 mmol/L) increased cancer risk (381 [1.6% py] versus 408 [1.7% py]; RR 0.92 [99% CI 0.76–1.10]).</p> <p>Conclusions: In 27 randomised trials, a median of five years of statin therapy had no effect on the incidence of, or mortality from, any type of cancer (or the aggregate of all cancer).</p&gt

Airway Mucin Concentration as a Marker of Chronic Bronchitis

Chronic obstructive pulmonary disease (COPD) is characterized by chronic bronchitic and emphysematous components. In one biophysical model, the concentration of mucin on the airway surfaces is hypothesized to be a key variable that controls mucus transport in healthy persons versus cessation of transport in persons with muco-obstructive lung diseases. Under this model, it is postulated that a high mucin concentration produces the sputum and disease progression that are characteristic of chronic bronchitis

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

Productive resistance within the public sector: exploring organisational culture

The article examines how South Korean civil servants responded to the introduction of pay for performance. Drawing upon 31 in-depth interviews with career civil servants, it identifies what became known as 1/n, a form of ‘discreet resistance’ that emerged and evolved. The analytical framework allows productive resistance to be seen as ebbing and flowing during organisational change that sees institutionalisation, deinstitutionalisation and re-institutionalisation. In understanding the cultural context of organisational resistance the contribution is three-fold. First, a nuanced definition and understanding of productive resistance. Second, it argues that productive resistance must be seen as part of a process that does not simply reflect ‘offer and counter-offer’ within the change management process. Thirdly, it identifies differences within groups and sub-cultures concerning commitment towards resistance and how these fissures contribute towards change as new interpretive schemes and justifications are presented in light of policy reformulations

Crop Updates 2002 - Oilseeds

This session covers twenty seven papers from different authors: 1. Forward and acknowledgements, Dave Eksteen, ACTING MANAGER OILSEEDS PRODUCTIVITY AND INDUSTRY DEVELOPMENT Department of Agriculture PLENARY SESSION 2. GMO canola - Track record in Canada, K. Neil Harker and George W. Clayton,Agriculture and Agri-Food Canada, Lacombe Research Centre, Lacombe, Alberta, R. Keith Downey, Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan 3. GMO canola – Prospects in Western Australia farming systems, Keith Alcock, Crop Improvement Institute, Department of Agriculture 4. Diamondback moth (DBM) in canola, Kevin Walden, Department of Agriculture CANOLA AGRONOMY 5. Getting the best out of canola in the low rainfall central wheatbelt, Bevan Addison and Peter Carlton, Elders Ltd 6. Canola variety performance in Western Australia, Kevin Morthorpe, Stephen Addenbrooke and Alex Ford, Pioneer Hi-Bred Australia P/L 7. Relative performance of new canola varieties in Department of Agriculture variety trials in 2000 and 2001, S. Hasan Zaheer, GSARI, Department of Agriculture, G. Walton, Crop Improvement Institute, Department of Agriculture 8. Which canola cultivar should I sow? Imma Farré, CSIRO Plant Industry, Floreat, Bill Bowden,Western Australia Department of Agriculture 9. The effect of seed generation and seed source on yield and quality of canola, Paul Carmody, Department of Agriculture 10. The accumulation of oil in Brassica species, J.A. Fortescue and D.W. Turner, Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, B. Tan, PO Box 1249, South Perth 11. Potential and performance of alternative oilseeds in WA, Margaret C. Campbell, Centre for Legumes in Mediterranean Agriculture 12. Comparison of oilseed crops in WA, Ian Pritchard and Paul Carmody, Department of Agriculture, Centre for Cropping Systems, Margaret Campbell, Centre for Legumes in Mediterranean Agriculture 13. Identifying constraints to canola production, Dave Eksteen, Canola Development Officer, Department of Agriculture 14. Boron – should we be worried about it? Richard W. BellA, K. FrostA, Mike WongB, and Ross BrennanC , ASchool of Environmental Science, Murdoch University, BCSIRO Land and Water, CDepartment of Agriculture PEST AND DISEASE 15. Yield losses caused when Beet Western Yellows Virus infects canola, Roger Jones and Jenny Hawkes, Department of Agriculture, and Centre for Legumes in Mediterranean Agriculture 16. Influence of climate on aphid outbreaks and virus epidemics in canola, Debbie Thackray, Jenny Hawkes and Roger Jones, Centre for Legumes in Mediterranean Agriculture and Department of Agriculture 17. The annual shower of blackleg ascospores in canola: Can we predict and avoid it? Moin U. Salam, Ravjit K. Khangura, Art J. Diggle and Martin J. Barbetti, Department of Agriculture 18. Environmental influences on production and release of ascospores of blackleg and their implications in blackleg management in canola, Ravjit K. Khangura, Martin J. Barbetti , Moin U. Salam and Art J. Diggle, Department of Agriculture 19. WA blackleg resistance ratings on canola varieties form 2002, Ravjit Khangura, Martin J. Barbetti and Graham Walton, Department of Agriculture 20. Bronzed field beetle management in canola, Phil Michael, Department of Agriculture 21. DBM control in canola: Aerial versus boom application, Paul Carmody, Department of Agriculture 22. Effect of single or multiple spray trearments on the control of Diamondback moth (Plutella xylostella) and yield of canola at Wongan Hills, Françoise Berlandier, Paul Carmody and Christiaan Valentine, Department of Agriculture ESTABLISHMENT 23. GrainGuardÔ - A biosecurity plan for the canola industry, Greg Shea, Department of Agriculture 24. Large canola seed is best, particularly for deep sowing, Glen Riethmuller, Rafiul Alam, Greg Hamilton and Jo Hawksley, Department of Agriculture 25. Canola establishment with seed size, tines and discs, with and without stubble, Glen Riethmuller, Rafiul Alam, Greg Hamilton and Jo Hawksley, Department of Agriculture WEEDS 26. Role of Roundup ReadyÒ canola in the farming system, Art Diggle1, Patrick Smith2, Paul Neve3, Felicity Flugge4, Amir Abadi5, Stephen Powles3 1Department of Agriculture, 2CSIRO, Sustainable Ecosystems, 3Western Australian Herbicide Resistance Initiative, University of Western Australia, 4Centre for Legumes in Mediterranean Agriculture, University of Western Australia, 5Touchstone Consulting, Mt Hawthorn FEED 27. Getting value from canola meals in the animal feed industries: Aquaculture, Brett Glencross and John Curnow, Department of Fisheries - Government of Western Australia and Wayne Hawkins, Department of Agricultur

Applicant perspectives during selection

We provide a comprehensive but critical review of research on applicant reactions to selection procedures published since 2000 (n = 145), when the last major review article on applicant reactions appeared in the Journal of Management. We start by addressing the main criticisms levied against the field to determine whether applicant reactions matter to individuals and employers (“So what?”). This is followed by a consideration of “What’s new?” by conducting a comprehensive and detailed review of applicant reaction research centered upon four areas of growth: expansion of the theoretical lens, incorporation of new technology in the selection arena, internationalization of applicant reactions research, and emerging boundary conditions. Our final section focuses on “Where to next?” and offers an updated and integrated conceptual model of applicant reactions, four key challenges, and eight specific future research questions. Our conclusion is that the field demonstrates stronger research designs, with studies incorporating greater control, broader constructs, and multiple time points. There is also solid evidence that applicant reactions have significant and meaningful effects on attitudes, intentions, and behaviors. At the same time, we identify some remaining gaps in the literature and a number of critical questions that remain to be explored, particularly in light of technological and societal changes

Asymmetric Genome Organization in an RNA Virus Revealed via Graph-Theoretical Analysis of Tomographic Data

Cryo-electron microscopy permits 3-D structures of viral pathogens to be determined in remarkable detail. In particular, the protein containers encapsulating viral genomes have been determined to high resolution using symmetry averaging techniques that exploit the icosahedral architecture seen in many viruses. By contrast, structure determination of asymmetric components remains a challenge, and novel analysis methods are required to reveal such features and characterize their functional roles during infection. Motivated by the important, cooperative roles of viral genomes in the assembly of single-stranded RNA viruses, we have developed a new analysis method that reveals the asymmetric structural organization of viral genomes in proximity to the capsid in such viruses. The method uses geometric constraints on genome organization, formulated based on knowledge of icosahedrally-averaged reconstructions and the roles of the RNA-capsid protein contacts, to analyse cryo-electron tomographic data. We apply this method to the low-resolution tomographic data of a model virus and infer the unique asymmetric organization of its genome in contact with the protein shell of the capsid. This opens unprecedented opportunities to analyse viral genomes, revealing conserved structural features and mechanisms that can be targeted in antiviral drug desig

The NANOGrav Nine-year Data Set:Observations, Arrival Time Measurements, and Analysis of 37 Millisecond Pulsars

We present high-precision timing observations spanning up to nine years for 37 millisecond pulsars monitored with the Green Bank and Arecibo radio telescopes as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project. We describe the observational and instrumental setups used to collect the data, and methodology applied for calculating pulse times of arrival; these include novel methods for measuring instrumental offsets and characterizing low signal-to-noise ratio timing results. The time of arrival data are fit to a physical timing model for each source, including terms that characterize time-variable dispersion measure and frequency-dependent pulse shape evolution. In conjunction with the timing model fit, we have performed a Bayesian analysis of a parameterized timing noise model for each source, and detect evidence for excess low-frequency, or "red," timing noise in 10 of the pulsars. For 5 of these cases this is likely due to interstellar medium propagation effects rather than intrisic spin variations. Subsequent papers in this series will present further analysis of this data set aimed at detecting or limiting the presence of nanohertz-frequency gravitational wave signals