394 research outputs found

    An Online Tutor for Astronomy: The GEAS Self-Review Library

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    We introduce an interactive online resource for use by students and college instructors in introductory astronomy courses. The General Education Astronomy Source (GEAS) online tutor guides students developing mastery of core astronomical concepts and mathematical applications of general astronomy material. It contains over 12,000 questions, with linked hints and solutions. Students who master the material quickly can advance through the topics, while under-prepared or hesitant students can focus on questions on a certain topic for as long as needed, with minimal repetition. Students receive individual accounts for study and course instructors are provided with overview tracking information, by time and by topic, for entire cohorts of students. Diagnostic tools support self-evaluation and close collaboration between instructor and student, even for distance learners. An initial usage study shows clear trends in performance which increase with study time, and indicates that distance learners using these materials perform as well as or better than a comparison cohort of on-campus astronomy students. We are actively seeking new collaborators to use this resource in astronomy courses and other educational venues.Comment: 15 pages, 9 figures; Vogt, N. P., and A. S. Muise. 2015. An online tutor for general astronomy: The GEAS self-review library. Cogent Education, 2 (1

    MR imaging as a monitoring tool for gonadal growth in fish

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    An in vivo approach of magnetic resonance imaging (MRI) will be presented to follow the gonadal development of unanaesthetised male and female polar cod (Boreogadus saida). The first screening procedure was carried out on a set of reproductive polar cod every four weeks. Gonad maturation was followed from November until shortly before spawning in February. The resolution of the MR images allowed for specific sex determination and calculation of gonads volumes. The results of calculated gonad volume in vivo was in agreement with the in vitro gonad weight

    Preventable admissions and emergency-department-visits in pediatric asylum-seeking and non-asylum-seeking patients

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    Background Migrant health has become an essential part of public health. According to the World Health Organization, many health systems in Europe have not yet adapted adequately to the needs of asylum-seekers, which might result in untimely and inefficient health care for asylum-seeking patients. The aim of this study was to assess the number of preventable hospital admissions and emergency department visits in asylum-seeking and non-asylum-seeking pediatric patients. Methods This is a retrospective, hospital-based study. The study was done at the University Children’s Hospital Basel in Switzerland. Patients admitted or presenting to the emergency department were included and split into the groups of asylum-seeking and non-asylum-seeking patients. All admissions and emergency-department visits were extracted from the administrative electronic health records from 1st Jan 2016-31st Dec 2017. The main outcome was the proportion of admissions due to ambulatory-care-sensitive conditions (which refer to conditions for which admission can be prevented by early interventions in primary care) in asylum-seeking and non-asylum-seeking patients. Ambulatory-care-sensitive conditions were defined by a validated list of ICD-10 codes. The secondary objective was to assess the number of preventable emergency-department visits by asylum-seeking patients defined as proportion of visits with a non-urgent triage score. Results A total of 75′199 hospital visits were included, of which 63′405 were emergency department visits and 11′794 were admissions. Ambulatory-care-sensitive conditions accounted for 12.1% (18/149) of asylum-seeking and 10.9% (1270/11645) of non-asylum seeking patients’ admissions. Among the emergency department visits by asylum-seeking patients, non-urgent conditions accounted for 82.2% (244/297). Conclusions Admissions due to ambulatory-care-sensitive conditions are comparable in asylum-seeking and non-asylum-seeking children, suggesting few delayed presentations to ambulatory care facilities. Strategies to prevent non-urgent visits at pediatric emergency department facilities are needed.publishedVersio

    The Rotation Curves of Galaxies at Intermediate Redshift

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    We have undertaken a pilot project to measure the rotation velocities of spiral galaxies in the redshift range 0.18 < z < 0.4 using high dispersion long slit spectroscopy obtained with the Palomar 5m telescope. One field galaxy and three cluster objects known to have strong emission lines were observed over wavelength ranges covering the redshifted lines of [OII], CaII K, H beta, and [OIII]. Two of the objects show extended line emission that allows the tracing of the rotation curve in one or more lines. A line width similar to that obtained with single dish telescopes for the 21-cm HI line observed in lower redshift galaxies can be derived from the observed H beta, [OII], and [OIII] emission by measuring a characteristic width from the velocity histogram. These moderately distant galaxies have much stronger emission lines than typical low-redshift spirals but they appear to be kinematically similar. Application of the Tully-Fisher relation suggests that the two galaxies with rotation curves are intrinsically brighter at R-band than nearby galaxies.Comment: Text is 15 pages (18 with figures). Full text and postscript figures are also available at http://www.ucolick.org/~nicole/pubs/pubs.html#highz

    Health care provided to recent asylumseeking and non-asylum-seeking pediatric patients in 2016 and 2017 at a Swiss tertiary hospital - a retrospective study

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    Background Asylum-seeking children represent an increasing and vulnerable group of patients whose health needs are largely unmet. Data on the health care provision to asylum-seeking children in European contexts is scarce. In this study we compare the health care provided to recent asylum-seeking and non-asylum-seeking children at a Swiss tertiary hospital. Methods We performed a cross-sectional retrospective study in a pediatric tertiary care hospital in Basel, Switzerland. All patients and visits from January 2016 to December 2017 were identified, using administrative and medical electronic health records. The asylum-seeking status was systematically assessed and the patients were allocated accordingly in the two study groups. Results A total of 202,316 visits by 55,789 patients were included, of which asylum-seeking patients accounted for 1674 (1%) visits by 439 (1%) individuals. The emergency department recorded the highest number of visits in both groups with a lower proportion in asylum-seeking compared to non-asylum-seeking children: 19% (317/1674) and 32% (64,315/200,642) respectively. The median number of visits per patient was 1 (IQR 1–2) in the asylum-seeking and 2 (IQR 1–4) in the non-asylum-seeking children. Hospital admissions were more common in asylum-seeking compared to non-asylum-seeking patients with 11% (184/1674) and 7% (14,692/200,642). Frequent visits (> 15 visits per patient) accounted for 48% (807/1674) of total visits in asylum-seeking and 25% (49,886/200,642) of total visits in non-asylum-seeking patients. Conclusions Hospital visits by asylum-seeking children represented a small proportion of all visits. The emergency department had the highest number of visits in all patients but was less frequently used by asylum-seeking children. Frequent care suggests that asylum-seeking patients also present with more complex diseases. Further studies are needed, focusing on asylum-seeking children with medical complexity.publishedVersio

    Tracking gonadal development in fish: An in vivo MRI study on polar cod, Boreogadus saida (Lepechin, 1774)

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    AbstractMagnetic resonance imaging (MRI) was applied to determine the sex of polar cod (Boreogadus saida Lepechin, 1774) (Actinopterygii: Gadidae) and to follow the gonadal development in individual animals over time. Individual unanaesthetised fish were transferred to a measurement chamber inside a preclinical 9.4 T MRI scanner and continuously perfused with aerated seawater. A screening procedure at an average of 3.5 h, consisting of a set of MRI scans of different orientations, was repeated every 4 weeks on the same set of reproducing B. saida (n = 10) with a body length of about 20 cm. Adapted multi‐slice flow‐compensated fast low‐angle shot (FcFLASH) and rapid acquisition with relaxation enhancement (RARE) protocols with an in‐plane resolution of 313 μm and an acquisition time of 2.5 min were used to visualise the morphology of various organs, including the gonads within the field of view (FOV). The MR images provided high resolution, enabling specific sex determination, calculation of gonad volumes, and determination of oocyte sizes. Gonad maturation was followed over 4 months from November 2021 until shortly before spawning in February 2022. The gonad volume increased by 2.3–25.5% for males and by 11.5–760.7% for females during the observation period. From October to February, the oocyte diameter increased from 427 μm (n = 1) to 1346 ± 27 μm (n = 4). Interestingly, individual oocytes showed changes in MR contrast over time that can be attributed to the morphological development of the oocytes. The results fit well with previous literature data from classical invasive studies. The presented approach has great potential for various ecophysiological applications such as monitoring natural or delayed development of internal organs or sex determination under different environmental conditions.</jats:p

    Evolution of the Near-Infrared Tully-Fisher Relation: Constraints on the Relationship Between the Stellar and Total Masses of Disk Galaxies since z=1

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    Using a combination of Keck spectroscopy and near-infrared imaging, we investigate the K-band and stellar mass Tully-Fisher relation for 101 disk galaxies at 0.2 < z < 1.2, with the goal of placing the first observational constraints on the assembly history of halo and stellar mass. Our main result is a lack of evolution in either the K-band or stellar mass Tully-Fisher relation from z = 0 - 1.2. Furthermore, although our sample is not statistically complete, we consider it suitable for an initial investigation of how the fraction of total mass that has condensed into stars is distributed with both redshift and total halo mass. We calculate stellar masses from optical and near-infrared photometry and total masses from maximum rotational velocities and disk scale lengths, utilizing a range of model relationships derived analytically and from simulations. We find that the stellar/total mass distribution and stellar-mass Tully-Fisher relation for z > 0.7 disks is similar to that at lower redshift, suggesting that baryonic mass is accreted by disks along with dark matter at z < 1, and that disk galaxy formation at z < 1 is hierarchical in nature. We briefly discuss the evolutionary trends expected in conventional structure formation models and the implications of extending such a study to much larger samples.Comment: ApJ, in press, 9 page
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