157 research outputs found

    Where People Meet the Muck: An Integrated Assessment of Beach Muck and Public Perception at the Bay City State Recreation Area, Saginaw Bay, Lake Huron

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    In several regions of the Great Lakes, including Saginaw Bay, the proliferation of muck, decaying organics largely from aquatic plants such as Cladophora, has washed ashore, and is blamed for negatively affecting water quality and economic losses in the region. The current view is that excess nutrient loading into the system is a leading cause of this type of organic debris, though changes in food web dynamics may also be a contributing factor. Through an Integrated Assessment (IA) framework, we summarized the current state of knowledge on the causes and consequences of muck conditions at the Bay City State Recreation Area (BCSRA), including the socio-economic impacts of muck at the park and on the Saginaw Bay Region. Through this framework we identify potential management scenarios for addressing beach fouling at the BCSRA. Through a robust stakeholder engagement process, the IA team implemented a suite of models and surveys to understand public perception of muck-related issues and identified a series of feasible short and long-term management actions that could help alleviate and better manage the impacts of muck. Results indicate that even drastic reductions in external phosphorus loads will not eliminate Cladophora growth in the bay. Beach muck is likely a historical part of the system, and nutrient reduction programs may not prevent muck from fouling Saginaw Bay beaches. We identify a sustainable park management practice maybe reallocating resources previously designated for cleaning efforts to achieve bare, sandy beaches and promoting alternative ecological activities and attractions such as bird watching, kayaking, and nature walks in the park’s coastal marshes

    Banking from Leeds, not London: regional strategy and structure at the Yorkshire Bank, 1859–1952

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    Industrial philanthropist Edward Akroyd created the Yorkshire Penny Savings Bank in 1859. Despite competition from the Post Office Savings Bank after 1861 and a serious reserve problem in 1911, it sustained his overall strategy to become a successful regional bank. Using archival and contemporary sources to build on recent scholarship illustrating how savings banks were integrated into local economies and the complementary roles of philanthropy and paternalism, we analyse an English regional bank's strategy, including an assessment of strategic innovation, ownership changes and management structure. This will demonstrate that the founder's vision continued, even though the 1911 crisis radically altered both strategy and structure

    TOWARD IAVCEI GUIDELINES ON THE ROLES AND RESPONSIBILITIES OF SCIENTISTS INVOLVED IN VOLCANIC HAZARD EVALUATION, RISK MITIGATION AND CRISIS RESPONSE

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    The International Association for Volcanology and Chemistry of the Earth’s Interior (IAVCEI), as the representative international association of scientists working on volcanic hazard evaluations and risk mitigation, promotes sustained open discussion within the scientific community of many relevant issues, including the following: & how to best understand and forecast volcanic activity, the associated hazards, and contribute to risk evaluations; & the appropriate roles and responsibilities of scientists prior to, during, and after crises; & the nature of scientists’ relationships with government authorities, populations at risk, and the media; & the manner and extent of involvement of scientists in processes that eventually lead authorities to make decisions, the extent of the liability or vulnerability of scientists to the outcomes of these decisions, and the way that scientists’ input may be perceived and judged by others; & the role of national and local culture and perception of risk in both mitigation policy and communication of hazard and risk; & the effectiveness of descriptions of forecasted volcanic phenomena and associated hazards, and of their related uncertainties; & how to best increase the awareness, preparedness and empowerment of individuals, and society as a whole, in order to reduce the impact of volcanic phenomena on society In particular, IAVCEI, as a modern learned society wants to offer through its media (e.g., its website, archives, documents, recommendation notes) informative material, which can help members and others to fulfill these roles and responsibilities. In particular, scientists have a role in protecting populations and societies from harm due to volcanic phenomena, within the context of, and being cognizant of, diverse cultural needs and settings. Furthermore, IAVCEI wants to develop frameworks within which relationships and communication with local communities, media, and authorities can be fostered and improve

    Homogeneously derived transit timings for 17 exoplanets and reassessed TTV trends for WASP-12 and WASP-4

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    We homogeneously analyse ∼3.2 × 105 photometric measurements for ∼1100 transit lightcurves belonging to 17 exoplanet hosts. The photometric data cover 16 years 2004–2019 and include amateur and professional observations. Old archival lightcurves were reprocessed using up-to-date exoplanetary parameters and empirically debiased limb-darkening models. We also derive self-consistent transit and radial-velocity fits for 13 targets. We confirm the nonlinear TTV trend in the WASP-12 data at a high significance, and with a consistent magnitude. However, Doppler data reveal hints of a radial acceleration about ( − 7.5 ± 2.2) m/s/yr, indicating the presence of unseen distant companions, and suggesting that roughly 10 per cent of the observed TTV was induced via the light-travel (or Roemer) effect. For WASP-4, a similar TTV trend suspected after the recent TESS observations appears controversial and model-dependent. It is not supported by our homogeneus TTV sample, including 10 ground-based EXPANSION lightcurves obtained in 2018 simultaneously with TESS. Even if the TTV trend itself does exist in WASP-4, its magnitude and tidal nature are uncertain. Doppler data cannot entirely rule out the Roemer effect induced by possible distant companions

    Ephemeris refinement of 21 Hot Jupiter exoplanets with high timing uncertainties

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    Transit events of extrasolar planets offer a wealth of information for planetary characterization. However, for many known targets, the uncertainty of their predicted transit windows prohibits an accurate scheduling of follow-up observations. In this work, we refine the ephemerides of 21 Hot Jupiter exoplanets with the largest timing uncertainty. We collected 120 professional and amateur transit light curves of the targets of interest, observed with 0.3m to 2.2m telescopes, and analyzed them including the timing information of the planets discovery papers. In the case of WASP-117b, we measured a timing deviation compared to the known ephemeris of about 3.5 hours, for HAT-P-29b and HAT-P-31b the deviation amounted to about 2 hours and more. For all targets, the new ephemeris predicts transit timings with uncertainties of less than 6 minutes in the year 2018 and less than 13 minutes until 2025. Thus, our results allow for an accurate scheduling of follow-up observations in the next decade

    Mean sojourn time, overdiagnosis, and reduction in advanced stage prostate cancer due to screening with PSA: implications of sojourn time on screening

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    This study aimed to assess the mean sojourn time (MST) of prostate cancer, to estimate the probability of overdiagnosis, and to predict the potential reduction in advanced stage disease due to screening with PSA. The MST of prostate cancer was derived from detection rates at PSA prevalence testing in 43 842 men, aged 50–69 years, as part of the ProtecT study, from the incidence of non-screen-detected cases obtained from the English population-based cancer registry database, and from PSA sensitivity obtained from the medical literature. The relative reduction in advanced stage disease was derived from the expected and observed incidences of advanced stage prostate cancer. The age-specific MST for men aged 50–59 and 60–69 years were 11.3 and 12.6 years, respectively. Overdiagnosis estimates increased with age; 10–31% of the PSA-detected cases were estimated to be overdiagnosed. An interscreening interval of 2 years was predicted to result in 37 and 63% reduction in advanced stage disease in men 65–69 and 50–54 years, respectively. If the overdiagnosed cases were excluded, the estimated reductions were 9 and 54%, respectively. Thus, the benefit of screening in reducing advanced stage disease is limited by overdiagnosis, which is greater in older men

    ExoClock Project: An open platform for monitoring the ephemerides of Ariel targets with contributions from the public

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    The Ariel mission will observe spectroscopically around 1000 exoplanets to further characterise their atmospheres. For the mission to be as efficient as possible, a good knowledge of the planets' ephemerides is needed before its launch in 2028. While ephemerides for some planets are being refined on a per-case basis, an organised effort to collectively verify or update them when necessary does not exist. In this study, we introduce the ExoClock project, an open, integrated and interactive platform with the purpose of producing a confirmed list of ephemerides for the planets that will be observed by Ariel. The project has been developed in a manner to make the best use of all available resources: observations reported in the literature, observations from space instruments and, mainly, observations from ground-based telescopes, including both professional and amateur observatories. To facilitate inexperienced observers and at the same time achieve homogeneity in the results, we created data collection and validation protocols, educational material and easy to use interfaces, open to everyone. ExoClock was launched in September 2019 and now counts over 140 participants from more than 15 countries around the world. In this release, we report the results of observations obtained until the 15h of April 2020 for 119 Ariel candidate targets. In total, 632 observations were used to either verify or update the ephemerides of 83 planets. Additionally, we developed the Exoplanet Characterisation Catalogue (ECC), a catalogue built in a consistent way to assist the ephemeris refinement process. So far, the collaborative open framework of the ExoClock project has proven to be highly efficient in coordinating scientific efforts involving diverse audiences. Therefore, we believe that it is a paradigm that can be applied in the future for other research purposes, too

    Utilizing a Global Network of Telescopes to Update the Ephemeris for the Highly Eccentric Planet HD 80606 b and to Ensure the Efficient Scheduling of JWST

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    The transiting planet HD 80606 b undergoes a 1000 fold increase in insolation during its 111 days orbit due to it being highly eccentric (e = 0.93). The planet's effective temperature increases from 400 to over 1400 K in a few hours as it makes a rapid passage to within 0.03 au of its host star during periapsis. Spectroscopic observations during the eclipse (which is conveniently oriented a few hours before periapsis) of HD 80606 b with the James Webb Space Telescope (JWST) are poised to exploit this highly variable environment to study a wide variety of atmospheric properties, including composition, chemical and dynamical timescales, and large scale atmospheric motions. Critical to planning and interpreting these observations is an accurate knowledge of the planet's orbit. We report on observations of two full-transit events: 2020 February 7 as observed by the TESS spacecraft and 2021 December 7-8 as observed with a worldwide network of small telescopes. We also report new radial velocity observations which, when analyzed with a coupled model to the transits, greatly improves the planet's orbital ephemeris. Our new orbit solution reduces the uncertainty in the transit and eclipse timing of the JWST era from tens of minutes to a few minutes. When combined with the planned JWST observations, this new precision may be adequate to look for non-Keplerian effects in the orbit of HD 80606 b

    The 2017 May 20th^{\rm th} stellar occultation by the elongated centaur (95626) 2002 GZ32_{32}

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    We predicted a stellar occultation of the bright star Gaia DR1 4332852996360346368 (UCAC4 385-75921) (mV_{\rm V}= 14.0 mag) by the centaur 2002 GZ32_{32} for 2017 May 20th^{\rm th}. Our latest shadow path prediction was favourable to a large region in Europe. Observations were arranged in a broad region inside the nominal shadow path. Series of images were obtained with 29 telescopes throughout Europe and from six of them (five in Spain and one in Greece) we detected the occultation. This is the fourth centaur, besides Chariklo, Chiron and Bienor, for which a multi-chord stellar occultation is reported. By means of an elliptical fit to the occultation chords we obtained the limb of 2002 GZ32_{32} during the occultation, resulting in an ellipse with axes of 305 ±\pm 17 km ×\times 146 ±\pm 8 km. From this limb, thanks to a rotational light curve obtained shortly after the occultation, we derived the geometric albedo of 2002 GZ32_{32} (pVp_{\rm V} = 0.043 ±\pm 0.007) and a 3-D ellipsoidal shape with axes 366 km ×\times 306 km ×\times 120 km. This shape is not fully consistent with a homogeneous body in hydrostatic equilibrium for the known rotation period of 2002 GZ32_{32}. The size (albedo) obtained from the occultation is respectively smaller (greater) than that derived from the radiometric technique but compatible within error bars. No rings or debris around 2002 GZ32_{32} were detected from the occultation, but narrow and thin rings cannot be discarded.Comment: Accepted for publication in MNRAS (8-Dec.-2020), 15 pages, 9 figure

    Discovery of a young low-mass brown dwarf transiting a fast-rotating F-type star by the Galactic Plane eXoplanet (GPX) survey

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    We announce the discovery of GPX-1 b, a transiting brown dwarf with a mass of 19.7±1.619.7\pm 1.6 MJupM_{\mathrm{Jup}} and a radius of 1.47±0.101.47\pm0.10 RJupR_{\mathrm{Jup}}, the first sub-stellar object discovered by the Galactic Plane eXoplanet (GPX) survey. The brown dwarf transits a moderately bright (VV = 12.3 mag) fast-rotating F-type star with a projected rotational velocity vsini=40±10v\sin{ i_*}=40\pm10 km/s. We use the isochrone placement algorithm to characterize the host star, which has effective temperature 7000±2007000\pm200 K, mass 1.68±0.101.68\pm0.10 MSunM_{\mathrm{Sun}}, radius 1.56±0.101.56\pm0.10 RSunR_{\mathrm{Sun}} and approximate age 0.270.15+0.090.27_{-0.15}^{+0.09} Gyr. GPX-1 b has an orbital period of \sim1.75 d, and a transit depth of 0.90±0.030.90\pm0.03 %. We describe the GPX transit detection observations, subsequent photometric and speckle-interferometric follow-up observations, and SOPHIE spectroscopic measurements, which allowed us to establish the presence of a sub-stellar object around the host star. GPX-1 was observed at 30-min integrations by TESS in Sector 18, but the data is affected by blending with a 3.4 mag brighter star 42 arcsec away. GPX-1 b is one of about two dozen transiting brown dwarfs known to date, with a mass close to the theoretical brown dwarf/gas giant planet mass transition boundary. Since GPX-1 is a moderately bright and fast-rotating star, it can be followed-up by the means of Doppler tomography.Comment: 13 pages, 13 figures, accepted to MNRAS in May 202
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