The Low‐Energy Neutral Imager (LENI) Westlake, J. H.; Mitchell, D. G.; Brandt, P. C.‐son ...
Journal of geophysical research. Space physics,
September 2016, 2016-Sep, 2016-09-00, 20160901, Volume:
121, Issue:
9
Journal Article
Peer reviewed
Open access
To achieve breakthroughs in the areas of heliospheric and magnetospheric energetic neutral atom (ENA) imaging, a new class of instruments is required. We present a high angular resolution ENA imager ...concept aimed at the suprathermal plasma populations with energies between 0.5 and 20 keV. This instrument is intended for understanding the spatial and temporal structure of the heliospheric boundary recently revealed by Interstellar Boundary Explorer instrumentation and the Cassini Ion and Neutral Camera. The instrument is also well suited to characterize magnetospheric ENA emissions from low‐altitude ENA emissions produced by precipitation of magnetospheric ions into the terrestrial upper atmosphere, or from the magnetosheath where solar wind protons are neutralized by charge exchange, or from portions of the ring current region. We present a new technique utilizing ultrathin carbon foils, 2‐D collimation, and a novel electron optical design to produce high angular resolution (≤2°) and high‐sensitivity (≥10−3 cm2 sr/pixel) ENA imaging in the 0.5–20 keV energy range.
Key Points
The LENI instrument is capable of high angular resolution ENA imaging
The LENI instrument utilizes novel MCP collimation for ENA imaging
The LENI instrument is designed for heliospheric and magnetospheric imaging
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We present a study of the dust-to-gas ratios in five nearby galaxies: NGC 628 (M74), NGC 6503, NGC 7793, UGC 5139 (Holmberg I), and UGC 4305 (Holmberg II). Using Hubble Space Telescope broadband ...WFC3/UVIS UV and optical images from the Treasury program Legacy ExtraGalactic UV Survey (LEGUS) combined with archival HST/Advanced Camera for Surveys data, we correct thousands of individual stars for extinction across these five galaxies using an isochrone-matching (reddening-free Q) method. We generate extinction maps for each galaxy from the individual stellar extinctions using both adaptive and fixed resolution techniques and correlate these maps with neutral H i and CO gas maps from the literature, including the H i Nearby Galaxy Survey and the HERA CO-Line Extragalactic Survey. We calculate dust-to-gas ratios and investigate variations in the dust-to-gas ratio with galaxy metallicity. We find a power-law relationship between dust-to-gas ratio and metallicity, consistent with other studies of dust-to-gas ratio compared to metallicity. We find a change in the relation when H2 is not included. This implies that underestimation of N H 2 in low-metallicity dwarfs from a too-low CO-to-H2 conversion factor XCO could have produced too low a slope in the derived relationship between dust-to-gas ratio and metallicity. We also compare our extinctions to those derived from fitting the spectral energy distribution (SED) using the Bayesian Extinction and Stellar Tool for NGC 7793 and find systematically lower extinctions from SED fitting as compared to isochrone matching.
We report observations of a relatively long period of 3He-rich solar energetic particles (SEPs) measured by Solar Orbiter. The period consists of several well-resolved ion injections. The ...high-resolution STEREO-A imaging observations reveal that the injections coincide with extreme ultraviolet jets and brightenings near the east limb, not far from the nominal magnetic connection of Solar Orbiter. The jets originated in two adjacent, large, and complex active regions, as observed by the Solar Dynamics Observatory when the regions rotated into the Earth's view. It appears that the sustained ion injections were related to the complex configuration of the sunspot group and the long period of 3He-rich SEPs to the longitudinal extent covered by the group during the analyzed time period.
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Biogeochemical data from Welwick marsh (Humber Estuary, UK), an actively accreting saltmarsh, provides a decadal–centennial-scale natural analogue for likely future biogeochemical storage effects of ...managed realignment sites accreting either intertidal muds or saltmarsh. Marsh topographic profiles and progradation history from aerial photographs were combined with
137Cs and niobium contamination history to establish and verify chronology and sediment mass accumulation. These data, combined with down-core measurements of particulate organic carbon (C
org), organic nitrogen (N
org), particle reactive phosphorus and selected contaminant metal (Zn, Pb, Cu, As and Nb) contents were then used to calculate sediment and chemical storage terms and to quantify changes in these over time. These data are used to help predict likely future biogeochemical storage changes at managed realignment sites in the estuary. The net effect of returning some 26 km
2 of reclaimed land to intertidal environments now (about 25% of the maximum possible realignment storage identified for the estuary) could result in the storage of some 40,000 tonnes a
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1
of sediment which would also bury about 800 tonnes a
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1
of C
org and 40 tonnes a
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1
of N
org. Particulate contaminant P burial would be around 25 tonnes a
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1
along with ~
6 tonnes a
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1
contaminant Zn, 3 tonnes a
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1
contaminant Pb, and ~
1 tonnes a
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1
contaminant As and Cu. The study also shows that reclamation activities in the outer estuary since the mid-1700s has prevented, in total, the deposition of about 10 million tonnes of sediment, along with 320,000 tonnes of C
org and 16,000 tonnes of N
org. The study provides a mid-1990s baseline against which future measurements at the site can determine changes in burial fluxes and improvement or deterioration in contaminant metal contents of the sediments. The data are directly relevant for local managed realignment sites but also broadly indicative for sites generally on the European North Sea Coast.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We have used multi-wavelength Hubble Space Telescope WFC3 data of the starbursting spiral galaxy M83 in order to measure variations in the upper end of the stellar initial mass function (uIMF) using ...the production rate of ionizing photons in unresolved clusters with ages < or =, slant 8 Myr. As in earlier papers on M51 and NGC 4214, the uIMF in M83 is consistent with a universal IMF, and stochastic sampling of the stellar populations in the <, ~ 10 super(3) M sub(middot in circle) clusters are responsible for any deviations in this universality. The ensemble cluster population, as well as individual clusters, also imply that the most massive star in a cluster does not depend on the cluster mass. In fact, we have found that these small clusters seem to have an over-abundance of ionizing photons when compared to an expected universal or truncated IMF. This also suggests that the presence of massive stars in these clusters does not affect the star formation in a destructive way.
Pluto's Interaction With Energetic Heliospheric Ions Kollmann, P.; Hill, M. E.; Allen, R. C. ...
Journal of geophysical research. Space physics,
September 2019, 2019-09-00, 20190901, Volume:
124, Issue:
9
Journal Article
Peer reviewed
Open access
Pluto energies of a few kiloelectron volts and suprathermal ions with tens of kiloelectron volts and above. We measure this population using the Pluto Energetic Particle Spectrometer Science ...Investigation (PEPSSI) instrument on board the New Horizons spacecraft that flew by Pluto in 2015. Even though the measured ions have gyroradii larger than the size of Pluto and the cross section of its magnetosphere, we find that the boundary of the magnetosphere is depleting the energetic ion intensities by about an order of magnitude close to Pluto. The intensity is increasing exponentially with distance to Pluto and reaches nominal levels of the interplanetary medium at about 190RP distance. Inside the wake of Pluto, we observe oscillations of the ion intensities with a periodicity of about 0.2 hr. We show that these can be quantitatively explained by the electric field of an ultralow‐frequency wave and discuss possible physical drivers for such a field. We find no evidence for the presence of plutogenic ions in the considered energy range.
Plain Language Summary
Space around Pluto is not entirely empty but filled with solar wind plasma and ions that originate from interstellar space and are pushed outward by the solar wind. All planetary bodies interact with their surrounding medium. In the case of a magnetized body like Earth, this interaction is strong and creates a magnetosphere. Unmagnetized bodies like that of the dwarf planet Pluto have a much weaker interaction. What makes Pluto special is that it is far outside in our solar system and therefore embedded in relatively high intensities of interstellar ions. When New Horizons passed Pluto and measured the distribution of these ions, we found that Pluto is forming a wake in the interstellar ion flow. It is more difficult to deflect the motion of the relatively fast‐moving interstellar ions than it is to deflect the lower‐energy solar wind. Therefore, it was not obvious that we would observe this. Even Pluto's wake is not entirely empty because some interstellar ions do manage to enter. Another finding was that a wave is propagating within the tenuous medium of the wake. This wave modulates the ion intensities resembling a sound wave propagating through air and modulating the gas density.
Key Points
Pluto forms a wake for energetic heliospheric ions
Waves cause ion intensity oscillations in the wake
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The use of prophylactic antisepsis to protect against coronavirus disease 2019 (COVID-19) has been suggested. This study investigated hydrogen peroxide antisepsis (HPA) at two hospitals in Ghana.
...Cases of COVID-19 among healthcare workers (HCWs) using hydrogen peroxide (HP-HCWs) or not using hydrogen peroxide (NHP-HCWs), vaccinated or unvaccinated, were recorded at Shai-Osudoku Hospital (SODH), Dodowa, and Mount Olives Hospital (MOH), Techiman, between May 2020 and December 2021. The effect of HPA in all inpatients at MOH was also observed. Permutation tests were used to determine P values.
At SODH, there were 62 (13.5%) cases of COVID-19 among 458 NHP-HCWs but no cases among eight HP-HCWs (P=0.622) from May to December 2020. Between January and March 2021, 10 (2.7%) of 372 NHP-HCWs had COVID-19, but there were no cases among 94 HP-HCWs (P=0.206). At MOH, prior to HPA, 17 (20.2%) of 84 HCWs and five (1.4%) of 370 inpatients had COVID-19 in July 2020. From August 2020 to March 2021, two of 54 (3.7%) HCWs who stopped HPA had COVID-19; none of 32 NHP-HCWs contracted COVID-19. At SODH, none of 23 unvaccinated HP-HCWs and 35 (64%) of 55 unvaccinated NHP-HCWs had COVID-19 from April to December 2021 (P<0.0001). None of 34 vaccinated HP-HCWs and 53 (13.6%) of 390 vaccinated NHP-HCWs had COVID-19 (P=0.015). No inpatients on prophylactic HPA (total 7736) contracted COVID-19.
Regular, daily HPA protects HCWs from COVID-19, and curtails nosocomial spread of SARS-CoV-2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We present a time‐of‐flight mass spectrometer design for the measurement of ions in the ~30 keV to 10 MeV range for protons (up to ~40 MeV and ~150 MeV for He and heavy ions, respectively) and ~30 ...keV to 1 MeV range for electrons, covering half of the sky with 80 apertures. The instrument, known as the “Mushroom,” owing to its shape, solves the field of view problem for magnetospheric and heliospheric missions that employ three‐axis stabilized spacecraft, yet still require extended angular coverage; the Mushroom is also compatible with a spinning spacecraft. The most important new feature of the Mushroom is the method through which uncomplicated electrostatic optics and clean position sensing combine to permit many apertures to fit into a compact, low‐mass sensor head (or wedge), several of which (ideally eight) compose a full instrument. Most of the sensor head's volume is an empty, equipotential region, resulting in the modest 250 g mass of each 10‐aperture wedge. The Mushroom is capable of separating ion species across most of its energy range and angular field of view. For example, separation of the neighboring 3He and 4He isotopes is excellent; the full width at half maximum mass resolution has been measured to be 0.24 amu to 0.32 amu, respectively. Converting this to a Gaussian width σm in mass m, this represents a σm/m mass resolution better than 0.04. This separation is highly desirable for the flight program for which the first Mushroom was built, the Solar Probe Plus mission. More generally, we estimate the mass resolution to be σm/m ≈ 0.1, but this is energy, mass, and angularly dependent. We also discuss the solid‐state detector stack capability, which extends the energy range of protons and helium, with composition, to ~100 MeV.
Key Points
Anisotropy, pitch angle distributions, and large field of view are important for energetic ion and electron science
The “Mushroom” instrument has been developed by JHU/APL to provide needed large FOV and angular resolution
The first Mushroom, EPI‐Lo, part of the ISʘIS investigation on Solar Probe Plus, has achieved excellent composition and spatial separation
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Pathogenic somatic variants affecting the genes
(
) are extensively linked to the process of oncogenesis, in particular related to central nervous system tumors in children. Recently,
germline ...missense variants were described as the cause of a novel pediatric neurodevelopmental disorder. We aimed to investigate patterns of brain MR imaging of individuals carrying
germline variants.
In this retrospective study, we included individuals with proved
causative genetic variants and available brain MR imaging scans. Clinical and demographic data were retrieved from available medical records. Molecular genetic testing results were classified using the American College of Medical Genetics criteria for variant curation. Brain MR imaging abnormalities were analyzed according to their location, signal intensity, and associated clinical symptoms. Numeric variables were described according to their distribution, with median and interquartile range.
Eighteen individuals (10 males, 56%) with
germline variants were included. Thirteen of 18 individuals (72%) presented with a small posterior fossa. Six individuals (33%) presented with reduced size and an internal rotational appearance of the heads of the caudate nuclei along with an enlarged and squared appearance of the frontal horns of the lateral ventricles. Five individuals (28%) presented with dysgenesis of the splenium of the corpus callosum. Cortical developmental abnormalities were noted in 8 individuals (44%), with dysgyria and hypoplastic temporal poles being the most frequent presentation.
Imaging phenotypes in germline
affected individuals are related to brain features, including a small posterior fossa as well as dysgenesis of the corpus callosum, cortical developmental abnormalities, and deformity of lateral ventricles.
Research has identified a number of negative societal perceptions of nursing related to gendered stereotyping, subordination to doctors, low academic standards, limited career opportunities and poor ...pay and conditions, and importantly how these perceptions may affect levels of recruitment into nursing. Focusing specifically on nurses, research has also considered the extent to which these societal perceptions are realities in their workplaces, and the direct experiences that contribute to attrition from both nursing courses and jobs. However, to date, few research has actually bridged the above approaches and considered the perceptions that nursing students hold as they first enter their education and how these change, or are confirmed, as a result of their experiences. In this context, the current study uses a combined questionnaire (
n=650), interview (
n=30) and focus group (
n=7) methodology to investigate the experiences of students based at two British Universities. The findings suggest that many students were surprised, yet not overwhelmed, by the high academic standards required of them and came to recognize and value the tremendous knowledge, skills set and responsibilities of nurses as they acquired them. However, their experiences reinforced both society's and their own image of an underpaid, overworked profession that lacks respect and has low morale. The findings support media initiatives that emphasize nurses’ skills in order to influence public opinion. They also support a range of subtle changes in nurse education at the institutional level to make student life easier. Nevertheless, it is acknowledged that these may have a limited impact unless pay and conditions are adequately addressed at the national level.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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