39 research outputs found

    The L 98-59 System: Three Transiting, Terrestrial-Size Planets Orbiting A Nearby M Dwarf

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    We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-size planets transiting L 98-59 (TOI-175, TIC 307210830)—a bright M dwarf at a distance of 10.6 pc. Using the Gaia-measured distance and broadband photometry, we find that the host star is an M3 dwarf. Combined with the TESS transits from three sectors, the corresponding stellar parameters yield planet radii ranging from 0.8 R⊕ to 1.6 R⊕. All three planets have short orbital periods, ranging from 2.25 to 7.45 days with the outer pair just wide of a 2:1 period resonance. Diagnostic tests produced by the TESS Data Validation Report and the vetting package DAVE rule out common false-positive sources. These analyses, along with dedicated follow-up and the multiplicity of the system, lend confidence that the observed signals are caused by planets transiting L 98-59 and are not associated with other sources in the field. The L 98-59 system is interesting for a number of reasons: the host star is bright (V = 11.7 mag, K = 7.1 mag) and the planets are prime targets for further follow-up observations including precision radial-velocity mass measurements and future transit spectroscopy with the James Webb Space Telescope; the near-resonant configuration makes the system a laboratory to study planetary system dynamical evolution; and three planets of relatively similar size in the same system present an opportunity to study terrestrial planets where other variables (age, metallicity, etc.) can be held constant. L 98-59 will be observed in four more TESS sectors, which will provide a wealth of information on the three currently known planets and have the potential to reveal additional planets in the system

    Projected WIMP sensitivity of the LUX-ZEPLIN dark matter experiment

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    LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4 × 10-48cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3 × 10−43 cm2 (7.1 × 10−42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020

    Vascular Remodeling in Health and Disease

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    The term vascular remodeling is commonly used to define the structural changes in blood vessel geometry that occur in response to long-term physiologic alterations in blood flow or in response to vessel wall injury brought about by trauma or underlying cardiovascular diseases.1, 2, 3, 4 The process of remodeling, which begins as an adaptive response to long-term hemodynamic alterations such as elevated shear stress or increased intravascular pressure, may eventually become maladaptive, leading to impaired vascular function. The vascular endothelium, owing to its location lining the lumen of blood vessels, plays a pivotal role in regulation of all aspects of vascular function and homeostasis.5 Thus, not surprisingly, endothelial dysfunction has been recognized as the harbinger of all major cardiovascular diseases such as hypertension, atherosclerosis, and diabetes.6, 7, 8 The endothelium elaborates a variety of substances that influence vascular tone and protect the vessel wall against inflammatory cell adhesion, thrombus formation, and vascular cell proliferation.8, 9, 10 Among the primary biologic mediators emanating from the endothelium is nitric oxide (NO) and the arachidonic acid metabolite prostacyclin [prostaglandin I2 (PGI2)], which exert powerful vasodilatory, antiadhesive, and antiproliferative effects in the vessel wall

    Aggregation and the matching of scales in spatial economics and landscape ecology: empirical evidence and prospects for integration

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    Grain and extent of spatially explicit studies in landscape ecology and spatial economics have been reviewed in an assessment of differences between these two disciplines and possibilities for integration. In the latter field, (1) such papers were substantially less frequently found, and (2) median study area grains as well as extents were higher. We found no evidence of a different definition of spatial scale, but did find major differences between the two fields in embedding in theory (well-developed in spatial economy) and spatial realism (better in landscape ecology). Where studies integrated both fields, matching of the spatial scales was generally imposed by the data bases available and kept implicit in the derivation of research aims. In multidisciplinary environmental assessment, explicit matching of scales is often neglected. We evaluate three possible approaches to guide this matching exercise, and conclude that a local compromise for a specific landscape is probably the best achievable. We found no evidence for the existence of a limited set of convergent and globally overarching spatial scales that is of practical use. © 2004 Elsevier B.V. All rights reserved

    Perceived Care and Well-being of Patients with Cancer and Matched Norm Participants in the COVID-19 Crisis: Results of a Survey of Participants in the Dutch PROFILES Registry

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    Importance: As the resolution of the coronavirus disease 2019 (COVID-19) crisis is unforeseeable, and/or a second wave of infections may arrive in the fall of 2020, it is important to evaluate patients' perspectives to learn from this. Objective: To assess how Dutch patients with cancer perceive cancer treatment and follow-up care (including experiences with telephone and video consultations [TC/VC]) and patients' well-being in comparison with a norm population during the COVID-19 crisis. Design, Setting, and Participants: Cross-sectional study of patients participating in the Dutch Patient Reported Outcomes Following Initial Treatment and Long-term Evaluation of Survivorship (PROFILES) registry and a norm population who completed a questionnaire from April to May 2020. Main Outcomes and Measures: Logistic regression analysis assessed factors associated with changes in cancer care (treatment or follow-up appointment postponed/canceled or changed to TC/VC). Differences in quality of life, anxiety/depression, and loneliness between patients and age-matched and sex-matched norm participants were evaluated with regression models. Results: The online questionnaire was completed by 4094 patients (48.6% response), of whom most were male (2493 [60.9%]) and had a mean (SD) age of 63.0 (11.1) years. Of these respondents, 886 (21.7%) patients received treatment; 2725 (55.6%) received follow-up care. Treatment or follow-up appointments were canceled for 390 (10.8%) patients, whereas 160 of 886 (18.1%) in treatment and 234 of 2725 (8.6%) in follow-up had it replaced by a TC/VC. Systemic therapy, active surveillance, or surgery were associated with cancellation of treatment or follow-up appointment. Younger age, female sex, comorbidities, metastasized cancer, being worried about getting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and receiving supportive care were associated with replacement of a consultation with a TC/VC. Patients and norm participants reported that the COVID-19 crisis made them contact their general practitioner (852 of 4068 [20.9%] and 218 of 979 [22.3%]) or medical specialist/nurse (585 of 4068 [14.4%] and 144 of 979 [14.7%]) less quickly when they had physical complaints or concerns. Most patients who had a TC/VC preferred a face-to-face consultation, but 151 of 394 (38.3%) were willing to use a TC/VC again. Patients with cancer were more worried about getting infected with SARS-CoV-2 compared with the 977 norm participants (917 of 4094 [22.4%] vs 175 of 977 [17.9%]). Quality of life, anxiety, and depression were comparable, but norm participants more often reported loneliness (114 of 977 [11.7%] vs 287 of 4094 [7.0%]) than patients with cancer (P =.009). Conclusions and Relevance: Among patients with cancer in the Netherlands, 1 in 3 reported changes in cancer care in the first weeks of the COVID-19 crisis. Long-term outcomes need to be monitored. The crisis may affect the mental well-being of the general population relatively more than that of patients with cancer
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