3,200 research outputs found

    Brussels blog round up for 17– 23 November: Budget troubles, France is downgraded, and are European young farmers facing extinction?

    Get PDF
    Chris Gilson and Stuart A Brown take a look at the week in Brussels blogging

    Sport Tourists in a Gaming Destination: Predicting Gaming and Non-Gaming Expenditures

    Full text link
    Sport tourism is the fastest growing segment of the tourism industry. Although there are a number of benefits to cities as a result of sport tourism, the most desired aspect of hosting contests is economic impact. This study examined the gaming and non-gaming impact of six major sporting events held in Las Vegas over a ten-year period. The results indicate that length of stay is a significant contributor to economic impact and that sport tourism has an important role to play in the economy of Las Vegas

    When can gravitational-wave observations distinguish between black holes and neutron stars?

    Get PDF
    Gravitational-wave observations of compact binaries have the potential to uncover the distribution of masses and angular momenta of black holes and neutron stars in the universe. The binary components' physical parameters can be inferred from their effect on the phasing of the gravitational-wave signal, but a partial degeneracy between the components' mass ratio and their angular momenta limits our ability to measure the individual component masses. At the typical signal amplitudes expected by the Advanced Laser Interferometer Gravitational-wave Observatory (signal-to-noise ratios between 10 and 20), we show that it will in many cases be difficult to distinguish whether the components are neutron stars or black holes. We identify when the masses of the binary components could be unambiguously measured outside the range of current observations: a system with a chirp mass M≤0.871\mathcal{M} \le 0.871 M⊙_\odot would unambiguously contain the smallest-mass neutron star observed, and a system with \mathcal{M} \ge 2.786 \Msun must contain a black hole. However, additional information would be needed to distinguish between a binary containing two 1.35 M⊙_\odot neutron stars and an exotic neutron-star--black-hole binary. We also identify those configurations that could be unambiguously identified as black-hole binaries, and show how the observation of an electromagnetic counterpart to a neutron-star--black-hole binary could be used to constrain the black-hole spin.Comment: 5 pages, 4 figures. Final version to be published in Ap.J.Let

    Imaging the Haro 6-10 Infrared Companion

    Get PDF
    We present an infrared imaging study of the low-mass pre-main-sequence binary system Haro 6-10. This system is one of a handful in which the optically visible primary has the characteristics of a normal T Tauri star, while the secondary is a so-called "infrared companion" (IRC), a strongly extincted object that emits most of its luminosity in the infrared. A speckle holographic technique was used to produce nearly diffraction-limited images on three nights over a 1 yr period starting in late 1997. The images show that the IRC is obscured and surrounded by a compact, irregular, and variable nebula. This structure is in striking contrast to the well-ordered edge-on disk associated with HK Tauri B, the extincted companion to another T Tauri star of similar age. A new, resolved intensity peak was found 0".4 southwest of the IRC. We suggest that it may represent light scattered by a clump of dusty material illuminated by starlight escaping along an outflow-carved cavity in the IRC envelope. The primary star became fainter and the companion became more extended during the observing period

    An 11.6 Micron Keck Search For Exozodiacal Dust

    Get PDF
    We have begun an observational program to search nearby stars for dust disks that are analogous to the disk of zodiacal dust that fills the interior of our solar system. We imaged six nearby main-sequence stars with the Keck telescope at 11.6 microns, correcting for atmosphere-induced wavefront aberrations and deconvolving the point spread function via classical speckle analysis. We compare our data to a simple model of the zodiacal dust in our own system based on COBE/DIRBE observations and place upper limits on the density of exozodiacal dust in these systems.Comment: 10 pages, figure1, figure2, figure3, and figures 4a-

    Factors affecting recruitment into General Practice : a double binary choice approach

    Get PDF
    Recruitment to General Practice (GP) is currently low in many countries. Here we focus on two binary choices for junior doctors: first, whether to apply to GP; second, whether to accept a GP training place if offered. Previous attitudinal studies have indicated factors claimed to affect recruitment. The current study goes further by quantifying the relative impact of different factors on the propensity of candidates to apply to GP and accept a training place. An online questionnaire was sent to candidates applying to United Kingdom (UK) specialty training in 2015. Descriptive statistics and a path analysis evaluated the importance of various factors on GP applications. Our results were synthesised with an analysis of data from the online applications portal. With 3838 candidates responding to the survey, the path analysis showed that personality and previous GP experiences were strongly associated with the decision to apply. There was some evidence that it was easier to enter GP than other specialties; in terms of deciding whether to accept, the evidence suggests GP was a backup plan for around 9% of candidates who accepted a GP post. Our results indicate that recruitment initiatives should focus on candidates who apply to GP but not as first choice or consider GP but do not apply, particularly by providing substantial experience of GP and accentuating the positives of the specialty such as work-life balance and the intellectual challenge of working with patients in primary care. Acceptance of a GP place may also depend on competition for places in other specialties

    A First Principles Theory of Nuclear Magnetic Resonance J-Coupling in solid-state systems

    Full text link
    A method to calculate NMR J-coupling constants from first principles in extended systems is presented. It is based on density functional theory and is formulated within a planewave-pseudopotential framework. The all-electron properties are recovered using the projector augmented wave approach. The method is validated by comparison with existing quantum chemical calculations of solution-state systems and with experimental data. The approach has been applied to verify measured J-coupling in a silicophosphate structure, Si5O(PO4)6Comment: 9 page

    Linking healthcare associated norovirus outbreaks: a molecular epidemiologic method for investigating transmission.

    Get PDF
    BACKGROUND: Noroviruses are highly infectious pathogens that cause gastroenteritis in the community and in semi-closed institutions such as hospitals. During outbreaks, multiple units within a hospital are often affected, and a major question for control programs is: are the affected units part of the same outbreak or are they unrelated transmission events? In practice, investigators often assume a transmission link based on epidemiological observations, rather than a systematic approach to tracing transmission.Here, we present a combined molecular and statistical method for assessing:1) whether observed clusters provide evidence of local transmission and2) the probability that anecdotally|linked outbreaks truly shared a transmission event. METHODS: 76 healthcare associated outbreaks were observed in an active and prospective surveillance scheme of 15 hospitals in the county of Avon, England from April 2002 to March 2003. Viral RNA from 64 out of 76 specimens from distinct outbreaks was amplified by reverse transcription-PCR and was sequenced in the polymerase (ORF 1) and capsid (ORF 2) regions. The genetic diversity, at the nucleotide level, was analysed in relation to the epidemiological patterns. RESULTS: Two out of four genetic and epidemiological clusters of outbreaks were unlikely to have occurred by chance alone, thus suggesting local transmission. There was anecdotal epidemiological evidence of a transmission link among 5 outbreaks pairs. By combining this epidemiological observation with viral sequence data, the evidence of a link remained convincing in 3 of these pairs. These results are sensitive to prior beliefs of the strength of epidemiological evidence especially when the outbreak strains are common in the background population. CONCLUSION: The evidence suggests that transmission between hospitals units does occur. Using the proposed criteria, certain hypothesized transmission links between outbreaks were supported while others were refuted. The combined molecular/epidemiologic approach presented here could be applied to other viral populations and potentially to other pathogens for a more thorough view of transmission

    Template banks to search for compact binaries with spinning components in gravitational wave data

    Get PDF
    Gravitational waves from coalescing compact binaries are one of the most promising sources for detectors such as LIGO, Virgo and GEO600. If the components of the binary posess significant angular momentum (spin), as is likely to be the case if one component is a black hole, spin-induced precession of a binary's orbital plane causes modulation of the gravitational-wave amplitude and phase. If the templates used in a matched-filter search do not accurately model these effects then the sensitivity, and hence the detection rate, will be reduced. We investigate the ability of several search pipelines to detect gravitational waves from compact binaries with spin. We use the post-Newtonian approximation to model the inspiral phase of the signal and construct two new template banks using the phenomenological waveforms of Buonanno, Chen and Vallisneri. We compare the performance of these template banks to that of banks constructed using the stationary phase approximation to the non-spinning post-Newtonian inspiral waveform currently used by LIGO and Virgo in the search for compact binary coalescence. We find that, at the same false alarm rate, a search pipeline using phenomenological templates is no more effective than a pipeline which uses non-spinning templates. We recommend the continued use of the non-spinning stationary phase template bank until the false alarm rate associated with templates which include spin effects can be substantially reduced.Comment: 11 pages, 3 figure

    Identifying robust response options to manage environmental change using an ecosystem approach:a stress-testing case study for the UK

    Get PDF
    A diverse range of response options was evaluated in terms of their utility for sustaining ecosystem services in the UK. Robustness of response options was investigated by applying a ‘stress-testing’ method which evaluated expected performance against combined scenarios of socioeconomic and climate change. Based upon stakeholder feedback, a reference scenario representing current trends in climate and socioeconomic drivers (‘business-as-usual’) was used as a dynamic baseline against which to compare results of other scenarios. The robustness of response options was evaluated by their utility in different environmental and social contexts as represented by the scenarios, and linked to their adaptability to adjust to changing conditions. Key findings demonstrate that adaptability becomes increasingly valuable as the magnitude and rate of future change diverges from current trends. Stress-testing also revealed that individual responses in isolation are unlikely to be robust meaning there are advantages from integrating cohesive combinations (bundles) of response options to maximise their individual strengths and compensate for weaknesses. This identifies a role for both top-down and bottom-up responses, including regulation, spatial targeting, incentives and partnership initiatives, and their use in combination through integrated assessment and planning consistent with the adoption of an Ecosystem Approach. Stress-testing approaches can have an important role in future-proofing policy appraisals but important knowledge gaps remain, especially for cultural and supporting ecosystem services. Finally, barriers and enablers to the implementation of more integrated long-term adaptive responses were identified drawing on the ‘4 Is’ (Institutions, Information, Incentives, Identity) conceptual framework. This highlighted the crucial but usually understated role of identity in promoting ownership and uptake of responses
    • …
    corecore