84 research outputs found

    The Effects of Salinity and Acetaminophen on the Aquatic Snail Physa acuta

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    Pharmaceuticals are increasingly detected in water bodies, and their presence can negatively impact aquatic organisms. This effect can be amplified when combined with increasing salinity in freshwater ecosystems. Acetaminophen is a widely used analgesic that is commonly found in river, streams, and waters where it is discharged directly. Therefore, organisms present in these locations (e.g., insects, snails, amphibians, and fish) are likely to be affected by acetaminophen. In this study, we determined the effects of elevated salinity (0.68 g/L), acetaminophen (500 µg/L) and combined elevated salinity (0.68 g/L) and acetaminophen (500 µg/L), on the growth, reproduction, and movement of the freshwater snail Physa acuta. There were no effects on growth or reproduction. No changes were observed on movement in individual treatments groups; however, there was a significant effect in the combined treatment of salinity and acetaminophen. It is likely that an energetic trade-off between physiological mechanisms resulted in a synergistic negative effect on snails

    Experience-Based UDL Applications: Overcoming Barriers to Learning

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    The overall purpose of this study was to examine the autobiographical memory narrative as a way for graduate teacher candidates (TCs) to learn to identify (1) barriers to learning, (2) Universal Design for Learning (UDL) checkpoints to remove these barriers, and (3) strategies for addressing the UDL checkpoints and removing these barriers. This phenomenological study explored lived experiences of (a) UDL training in the graduate teacher preparation programs, (b) barriers to learning in the past experience, and (c) application of UDL principles to removing the self-identified barriers to learning among graduate TCs. Having a purposeful criterion sample at a site level to explore central phenomena in the study (Creswell & Poth, 2018), participants in the study included 63 graduate TCs in a teacher certification program at a university in the north eastern region of the United States. The participants dually took roles as a student, who identified barriers to their learning from the past experience, and as a teacher, who applied UDL principles to removing those self-identified barriers. Data were collected through each participant’s autobiographical narrative about (i) their past learning experience at any point in K-16 education, (ii) barrier to their own learning experience in the past, and (iii) UDL application to removing the identified learning barriers. Data were analyzed to identify frequency of barriers and types of strategies to remove these barriers across participants. Discussion includes identified (1) barriers to learning, (2) UDL checkpoints, and (3) strategies to apply the identified UDL checkpoints to removing these barriers. Emerging themes were aligned with the UDL guidelines (2018)

    Joint Modeling of Radial Velocities and Photometry with a Gaussian Process Framework

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    Developments in the stability of modern spectrographs have led to extremely precise instrumental radial velocity (RV) measurements. For most stars, the detection limit of planetary companions with these instruments is expected to be dominated by astrophysical noise sources such as starspots. Correlated signals caused by rotationally-modulated starspots can obscure or mimic the Doppler shifts induced by even the closest, most massive planets. This is especially true for young, magnetically active stars where stellar activity can cause fluctuation amplitudes of \gtrsim0.1 mag in brightness and \gtrsim100 m s1^{-1} in RV semi-amplitudes. Techniques that can mitigate these effects and increase our sensitivity to young planets are critical to improving our understanding of the evolution of planetary systems. Gaussian processes (GPs) have been successfully employed to model and constrain activity signals in individual cases. However, a principled approach of this technique, specifically for the joint modeling of photometry and RVs, has not yet been developed. In this work, we present a GP framework to simultaneously model stellar activity signals in photometry and RVs that can be used to investigate the relationship between both time series. Our method, inspired by the FF\textit{FF}^\prime framework of (Aigrain et al. 2012), models spot-driven activity signals as the linear combinations of two independent latent GPs and their time derivatives. We also simulate time series affected by starspots by extending the starry\texttt{starry} software (Luger et al. 2019) to incorporate time evolution of stellar features. Using these synthetic datasets, we show that our method can predict spot-driven RV variations with greater accuracy than other GP approaches.Comment: 19 pages, 10 figure

    Risk of COVID-19 after natural infection or vaccinationResearch in context

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    Summary: Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health

    Early Release Science of the Exoplanet WASP-39b with JWST NIRSpec G395H

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    Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking the formation and evolution of exoplanetary systems. Access to an exoplanet's chemical inventory requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based and high-resolution ground-based facilities. Here we report the medium-resolution (R\sim600) transmission spectrum of an exoplanet atmosphere between 3-5 μ\mum covering multiple absorption features for the Saturn-mass exoplanet WASP-39b, obtained with JWST NIRSpec G395H. Our observations achieve 1.46x photon precision, providing an average transit depth uncertainty of 221 ppm per spectroscopic bin, and present minimal impacts from systematic effects. We detect significant absorption from CO2_2 (28.5σ\sigma) and H2_2O (21.5σ\sigma), and identify SO2_2 as the source of absorption at 4.1 μ\mum (4.8σ\sigma). Best-fit atmospheric models range between 3 and 10x solar metallicity, with sub-solar to solar C/O ratios. These results, including the detection of SO2_2, underscore the importance of characterising the chemistry in exoplanet atmospheres, and showcase NIRSpec G395H as an excellent mode for time series observations over this critical wavelength range.Comment: 44 pages, 11 figures, 3 tables. Resubmitted after revision to Natur

    Early Release Science of the exoplanet WASP-39b with JWST NIRSpec G395H.

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    Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking the formation and evolution of exoplanetary systems1,2. Access to the chemical inventory of an exoplanet requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based3-5 and high-resolution ground-based6-8 facilities. Here we report the medium-resolution (R ≈ 600) transmission spectrum of an exoplanet atmosphere between 3 and 5 μm covering several absorption features for the Saturn-mass exoplanet WASP-39b (ref. 9), obtained with the Near Infrared Spectrograph (NIRSpec) G395H grating of JWST. Our observations achieve 1.46 times photon precision, providing an average transit depth uncertainty of 221 ppm per spectroscopic bin, and present minimal impacts from systematic effects. We detect significant absorption from CO2 (28.5σ) and H2O (21.5σ), and identify SO2 as the source of absorption at 4.1 μm (4.8σ). Best-fit atmospheric models range between 3 and 10 times solar metallicity, with sub-solar to solar C/O ratios. These results, including the detection of SO2, underscore the importance of characterizing the chemistry in exoplanet atmospheres and showcase NIRSpec G395H as an excellent mode for time-series observations over this critical wavelength range10

    HD 183579b: a warm sub-Neptune transiting a solar twin detected by TESS

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    We report the discovery and characterization of a transiting warm sub-Neptune planet around the nearby bright (V = 8.75 mag, K = 7.15 mag) solar twin HD 183579, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located 56.8 +/- 0.1 pc away with a radius of R-* = 0.97 +/- 0.02R(circle dot) and a mass of M-* = 1.03 +/- 0.05M(circle dot). We confirm the planetary nature by combining space and ground-based photometry, spectroscopy, and imaging. We find that HD 183579b (TOI-1055b) has a radius of R-p = 3.53 +/- 0.13R(circle plus) on a 17.47 d orbit with a mass of M-p = 11.2 +/- 5.4M(circle plus) (3 sigma mass upper limit of 27.4M(circle plus)). HD 183579b is the fifth brightest known sub-Neptune planet system in the sky, making it an excellent target for future studies of the interior structure and atmospheric properties. By performing a line-by-line differential analysis using the high-resolution and signal-to-noise ratio HARPS spectra, we find that HD 183579 joins the typical solar twin sample, without a statistically significant refractory element depletion

    Alberta Gambling Research Institute Conference 2021: Gambling in Canada: Current Research & Future Directions

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    Conference presentations and research posters presented at the event made available with the permission of the authors.The Alberta Gambling Research Institute's 20th Annual Conference "Gambling in Canada: Current Research & Future Directions" took place April 27-29, 2021 as a live virtual event. A selection of conference presentations and research posters presented at the event have been made available with the permission of the authors
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