566 research outputs found

    The EXPLORE Project I: A Deep Search for Transiting Extrasolar Planets

    Get PDF
    (Abridged) We discuss the design considerations of the EXPLORE (EXtra-solar PLanet Occultation REsearch) project, a series of transiting planet searches using 4-m-class telescopes to continuously monitor a single field of stars in the Galactic Plane in each ~2 week observing campaign. We discuss the general factors which determine the efficiency and the number of planets found by a transit search, including time sampling strategy and field selection. The primary goal is to select the most promising planet candidates for radial velocity follow-up observations. We show that with very high photometric precision light curves that have frequent time sampling and at least two detected transits, it is possible to uniquely solve for the main parameters of the eclipsing system (including planet radius) based on several important assumptions about the central star. Together with a measured spectral type for the star, this unique solution for orbital parameters provides a powerful method for ruling out most contaminants to transiting planet candidates. For the EXPLORE project, radial velocity follow-up observations for companion mass determination of the best candidates are done on 8-m-class telescopes within two or three months of the photometric campaigns. This same-season follow-up is made possible by the use of efficient pipelines to produce high quality light curves within weeks of the observations. We conclude by presenting early results from our first search, EXPLORE I, in which we reached <1% rms photometric precision (measured over a full night) on ~37,000 stars to I <= 18.2.Comment: accepted by ApJ. Main points unchanged but more thorough discussion of some issues. 36 pages, including 14 figure

    Research in the time of COVID

    Get PDF
    Editorial

    UK-South Asian patients' experiences of and satisfaction toward receiving information about biologics in rheumatoid arthritis

    Get PDF
    Background: Rheumatoid arthritis (RA) causes painful joint inflammation and is incurable, but treatments control RA. Drug regimens are complex, and patients often do not take their medication as expected. Poor medication adherence can lead to poorly controlled disease and worse patient outcomes. Biologics treatments are expensive and require full engagement from patients. We have previously shown that patients from Black ethnic minority backgrounds do not fully engage into treatment plan. This study explored the patients’ experiences in and satisfaction toward receiving information about biologics and future support preferences in South Asian patients with RA. Methods: Twenty South Asian patients with RA from Royal Wolverhampton Hospitals NHS Trust and Central Manchester University Hospitals NHS Foundation Trust participated in individual semi-structured interviews. Interviews were transcribed and data were analyzed by using thematic analysis approach. Results: Four overarching themes describe the patients’ experience in and satisfaction toward receiving information on biologics: 1) current provision of information regarding the “biologics journey” and understanding of RA: in this theme, non-English-speaking patients expressed heightened anxiety about stepping up to biologics; 2) experience and perceptions of biologics: many patients were positive about the biologic experience; however, there were patient-perceived delays in getting on to the biologics; 3) factors influencing willingness to try biologics: in this theme, a number of factors were identified including seeking advice from doctors abroad; and 4) recommendations on the desired information to fully understand the use of biologics: some patients valued group discussions, while others suggested receiving RA and biologic information through a video interaction. Conclusion: This novel study provides insight into South Asian RA patients’ experiences in and satisfaction toward receiving information about biologics. South Asian patients with RA reported a range of perceptions about biologics and support preferences, many of which may not be shared with the non-South Asian population

    The EXPLORE Project: A Deep Search for Transiting Extra-Solar Planets

    Get PDF
    Searching for transits provides a very promising technique for finding close-in extra-solar planets. Transiting planets present the advantage of allowing one to determine physical properties such as mass and radius unambiguously. The EXPLORE (EXtra-solar PLanet Occultation REsearch) project is a transit search project carried out using wide-field CCD imaging cameras on 4-m class telescopes, and 8-10m class telescopes for radial velocity verification of the photometric candidates. We describe some of the considerations that go into the design of the EXPLORE transit search to maximize the discovery rate and minimize contaminating objects that mimic transiting planets. We show that high precision photometry (2 to 10 millimag) and high time sampling (few minutes) are crucial for sifting out contaminating signatures, such as grazing binaries. We have completed two searches using the 8k MOSAIC camera at the CTIO4m and the CFH12k camera at CFHT, with runs covering 11 and 16 nights, respectively. We obtained preliminary light curves for approximately 47,000 stars with better than ~1% photometric precision. A number of light curves with flat-bottomed eclipses consistent with being produced by transiting planets has been discovered. Preliminary results from follow-up spectroscopic observations using the VLT UVES spectrograph and the Keck HIRES spectrograph obtained for a number of the candidates are presented. Data from four of these can be interpreted consistently as possible planet candidates, although further data are still required for definitive confirmations.Comment: 11 pages. To appear in the Proceedings of the SPIE conference: Astronomical Telescopes and Instrumentatio

    PacBio amplicon sequencing for metabarcoding of mixed DNA samples from lichen herbarium specimens.

    Full text link
    The detection and identification of species of fungi in the environment using molecular methods heavily depends on reliable reference sequence databases. However, these databases are largely incomplete in terms of taxon coverage, and a significant effort is required from herbaria and living fungal collections for the mass-barcoding of well-identified and well-curated fungal specimens or strains. Here, a PacBio amplicon sequencing approach is applied to recent lichen herbarium specimens for the sequencing of the fungal ITS barcode, allowing a higher throughput sample processing than Sanger sequencing, which often required the use of cloning. Out of 96 multiplexed samples, a full-length ITS sequence of the target lichenised fungal species was recovered for 85 specimens. In addition, sequences obtained for co-amplified fungi gave an interesting insight into the diversity of endolichenic fungi. Challenges encountered at both the laboratory and bioinformatic stages are discussed, and cost and quality are compared with Sanger sequencing. With increasing data output and reducing sequencing cost, PacBio amplicon sequencing is seen as a promising approach for the generation of reference sequences for lichenised fungi as well as the characterisation of lichen-associated fungal communities

    The role of peripheral ocular length and peripheral corneal radius of curvature in determining refractive error

    Get PDF
    PURPOSE: The purpose of this study was to extend the knowledge of peripheral biometric component and its relationship to refractive status in healthy individuals by determining the correlation between peripheral ocular length to peripheral corneal radius ratio and the refractive error. METHODS: This prospective study was conducted on thirty-three healthy adult participants. Refractive error was assessed objectively and subjectively and recorded as the mean spherical equivalent. Central and peripheral ocular lengths at 30° were assessed using partial coherence interferometry under dilation with 1% tropicamide. Central and peripheral corneal radius of curvature was assessed using Scheimpflug topography. Peripheral ocular lengths at 30° were paired with peripheral corneal curvatures at the incident points of the IOLMaster beam (3.8 mm away from corneal apex) superiorly, inferiorly, temporally and nasally to calculate the peripheral ocular length-peripheral corneal radius ratio. Descriptive statistics were used to describe the distribution and spread of the data. Pearson’s correlation analysis was used to present the association between biometric and refractive variables. RESULTS: Refractive error was negatively correlated with the axial length-central corneal radius ratio (r = −0.91; p < 0.001) and with 30° peripheral ocular length-peripheral corneal radius ratio in all four meridians (r ≀ −0.76; p < 0.001). The strength of the correlation was considerably lower when only axial length or peripheral ocular lengths were used. CONCLUSION: Using the ratios of peripheral ocular length-peripheral corneal radius to predict refractive error is more effective than using peripheral corneal radius or peripheral ocular length alone

    Trends in incidence and prevalence of osteoarthritis in the United Kingdom:findings from the Clinical Practice Research Datalink (CPRD)

    Get PDF
    Objective: This study aimed to explore the incidence and prevalence of OA in the UK in 2017 and their trends from 1997 to 2017 using a large nationally representative primary care database. Design: The UK Clinical Practice Research Datalink (CPRD) comprising data on nearly 17.5 million patients was used for the study. The incidence and prevalence of general practitioner diagnosed OA over a 20 years period (1997-2017) were estimated and age-sex and length of data contribution standardized using the 2017 CPRD population structure. Cohort effects were examined through Age-period-cohort analysis. Results: During 1997-2017, there were 494,716 incident OA cases aged ≄20 years. The standardised incidence of any OA in 2017 was 6.8 per 1000 person-years (95% CI 6.7 to 6.9) and prevalence was 10.7% (95% CI 10.7-10.8%). Both incidence and prevalence were higher in women than men. The incidence of any-OA decreased gradually in the past 20 years at an annual rate of -1.6% (95%CI -2.0 to -1.1%), and the reduction speeded up for people born after 1960. The prevalence of any-OA increased gradually at an annual rate of 1.4% (95% CI 1.3-1.6%). Although the prevalence was highest in Scotland and Northern Ireland, incidence was highest in the East Midlands. Both incidence and prevalence reported highest in the knee followed by hip, wrist/hand and ankle/foot. Conclusion: In the UK approximately one in 10 adults have symptomatic clinically diagnosed OA, the knee being the commonest. While prevalence has increased and become static after 2008, incidence is slowly declining. Further research is required to understand these changes
    • 

    corecore