Two Mars Atmosphere and Volatile EvolutioN magnetic field sensors sample the ambient magnetic field at the outer edge of each solar array. We characterized relatively minor spacecraft‐generated ...magnetic fields using in‐flight subsystem tests and spacecraft maneuvers. Dynamic spacecraft fields associated with the power subsystem (≤1 nT) are compensated for using spacecraft engineering telemetry to identify active solar array circuits and monitor their electrical current production. Static spacecraft magnetic fields are monitored using spacecraft roll maneuvers. Accuracy of measurement of the environmental magnetic field is demonstrated by comparison with field directions deduced from the symmetry properties of the electron distribution function measured by the Solar Wind Electron Analyzer. We map the bow shock, magnetic pileup boundary, the V × B convection electric field and ubiquitous proton cyclotron, and 1 Hz waves in the ion foreshock region.
Key Points
We observe, analyze, model, and mitigate spacecraft‐generated magnetic fields
Measured field vectors are independently validated using electron analyzer observations
We map the Mars magnetosphere, convection electric field, foreshock waves, and magnetotail
Astronomical wide-field imaging of interferometric radio data is computationally expensive, especially for the large data volumes created by modern non-coplanar many-element arrays. We present a new ...wide-field interferometric imager that uses the w-stacking algorithm and can make use of the w-snapshot algorithm. The performance dependences of casa's w-projection and our new imager are analysed and analytical functions are derived that describe the required computing cost for both imagers. On data from the Murchison Widefield Array, we find our new method to be an order of magnitude faster than w-projection, as well as being capable of full-sky imaging at full resolution and with correct polarization correction. We predict the computing costs for several other arrays and estimate that our imager is a factor of 2–12 faster, depending on the array configuration. We estimate the computing cost for imaging the low-frequency Square Kilometre Array observations to be 60 PetaFLOPS with current techniques. We find that combining w-stacking with the w-snapshot algorithm does not significantly improve computing requirements over pure w-stacking. The source code of our new imager is publicly released.
A study investigated the chemical and biological makeup of resveratrol-derived natural products, wine specifically, and examined whether there is a correlation between cardiovascular disease and ...cholesterol. There is evidence that resveratrol offers cadioprotective effects and has antidiabetic, anticancer and antioxidant benefits to its users.
Using the Murchison Widefield Array (MWA), the low-frequency Square Kilometre Array precursor located in Western Australia, we have completed the GaLactic and Extragalactic All-sky MWA (GLEAM) ...survey, and present the resulting extragalactic catalogue, utilizing the first year of observations. The catalogue covers 24 831 square degrees, over declinations south of +30... and Galactic latitudes outside 10... of the Galactic plane, excluding some areas such as the Magellanic Clouds. It contains 307 455 radio sources with 20 separate flux density measurements across 72-231 MHz, selected from a time- and frequency-integrated image centred at 200 MHz, with a resolution of ...2 arcmin. Over the catalogued region, we estimate that the catalogue is 90 per cent complete at 170 mJy, and 50 per cent complete at 55 mJy, and large areas are complete at even lower flux density levels. Its reliability is 99.97 per cent above the detection threshold of 5..., which itself is typically 50 mJy. These observations constitute the widest fractional bandwidth and largest sky area survey at radio frequencies to date, and calibrate the low-frequency flux density scale of the southern sky to better than 10 per cent. This paper presents details of the flagging, imaging, mosaicking and source extraction/characterization, as well as estimates of the completeness and reliability. All source measurements and images are available online. This is the first in a series of publications describing the GLEAM survey results. (ProQuest: ... denotes formulae/symbols omitted.)
Extensive work implicates abnormal amygdala activation in emotional facial expression processing in adults with callous-unemotional traits. However, no research has examined amygdala response to ...emotional facial expressions in adolescents with disruptive behavior and callous-unemotional traits. Moreover, despite high comorbidity of callous-unemotional traits and attention deficit hyperactivity disorder (ADHD), no research has attempted to distinguish neural correlates of pediatric callous-unemotional traits and ADHD.
Participants were 36 children and adolescents (ages 10-17 years); 12 had callous-unemotional traits and either conduct disorder or oppositional defiant disorder, 12 had ADHD, and 12 were healthy comparison subjects. Functional MRI was used to assess amygdala activation patterns during processing of fearful facial expressions. Patterns in the callous-unemotional traits group were compared with those in the ADHD and comparison groups.
In youths with callous-unemotional traits, amygdala activation was reduced relative to healthy comparison subjects and youths with ADHD while processing fearful expressions, but not neutral or angry expressions. Functional connectivity analyses demonstrated greater correlations between the amygdala and the ventromedial prefrontal cortex in comparison subjects and youths with ADHD relative to those with callous-unemotional traits. Symptom severity in the callous-unemotional traits groups was negatively correlated with connectivity between amygdala and ventromedial prefrontal cortex.
This is the first study to demonstrate reduced amygdala responsiveness in youths with callous-unemotional traits. These findings support the contention that callous and unemotional personality traits are associated with reduced amygdala response to distress-based social cues.
To investigate whether antibiotic exposure during the first year of life is associated with increased childhood body mass index (BMI).
Secondary analysis from a multi-centre, multi-country, ...cross-sectional study (The International Study of Asthma and Allergies in Childhood Phase Three).
A total of 74 946 children from 31 centres in 18 countries contributed data on antibiotic use in the first 12 months of life and current BMI.
Parents/guardians of children aged 5-8 years completed questionnaires that included questions about their children's current height and weight, and whether in the child's first 12 months of life, they had received any antibiotics, paracetamol, were breastfed or the mother/female guardian smoked cigarettes, and whether the child had wheezed in the past 12 months. A general linear mixed model was used to determine the association of antibiotic exposure with BMI, adjusting for age, sex, centre, BMI measurement type (self-reported or measured), maternal smoking, breastfeeding, paracetamol use, gross national income and current wheeze.
There was a significant interaction between sex and early-life antibiotic exposure. Early-life antibiotic exposure was associated with increased childhood BMI in boys (+0.107 kg m(-2), P<0.0001), but not in girls (-0.008 kg m(-2), P=0.75) after controlling for age, centre and BMI measurement type. The association remained in boys (+0.104 kg m(-2), P<0.0007), after adjustment for maternal smoking, breastfeeding, paracetamol use and current wheeze. There was no interaction between age, maternal smoking, breastfeeding, paracetamol use, gross national income and current wheeze in the association between early antibiotic exposure and BMI.
Exposure to antibiotics during the first 12 months of life is associated with a small increase in BMI in boys aged 5-8 years in this large international cross-sectional survey. By inference this provides additional support for the importance of gut microbiota in modulating the risk of obesity, with a sex-specific effect.
We draw a comparison between a solar energetic particle event associated with the release of a slow coronal mass ejection close to the Sun, and the energetic particle population produced in high ...current density field-aligned current structures associated with auroral phenomena in planetary magnetospheres. We suggest that this process is common in CME development and lift off in the corona, and may account for the electron populations that generate Type III radio bursts, as well as for the prompt energetic ion and electron populations typically observed in interplanetary space.
Mars Atmosphere and Volatile EvolutioN mission (MAVEN) observes a tenuous but ubiquitous flux of protons with the same energy as the solar wind in the Martian atmosphere. During high flux intervals, ...we observe a corresponding negative hydrogen population. The correlation between penetrating and solar wind fluxes, the constant energy, and the lack of a corresponding charged population at intermediate altitudes implicate products of hydrogen energetic neutral atoms from charge exchange between the upstream solar wind and the exosphere. These atoms, previously observed in neutral form, penetrate the magnetosphere unaffected by electromagnetic fields (retaining the solar wind velocity), and some fraction reconvert to charged form through collisions with the atmosphere. MAVEN characterizes the energy and angular distributions of both penetrating and backscattered particles, potentially providing information about the solar wind, the hydrogen corona, and collisional interactions in the atmosphere. The accretion of solar wind hydrogen may provide an important source term to the Martian atmosphere over the planet's history.
Key Points
We observe H+ and H− in the atmosphere of Mars, at the solar wind energy
Solar wind protons charge exchange and penetrate as ENAs then reconvert
MAVEN can monitor hydrogen deposition and backscatter in the atmosphere
Context.
The observation of numerous magnetic switchbacks and associated plasma jets in Parker Solar Probe (PSP) during its first five orbits, particularly near the Sun, has attracted considerable ...attention. Switchbacks have been found to be systematically associated with correlated reversals in the direction of the propagation of Alfvénic fluctuations, as well as similar reversals of the electron strahl.
Aims.
Here we aim to see whether the energetic particles change direction at the magnetic field switchbacks.
Methods.
We use magnetic field data from the MAG suite’s fluxgate magnetometer instrument to identify switchback regions. We examine the radial anisotropy of the energetic particles measured by the EPI-Lo instrument of the IS⊙IS suite.
Results.
We find that energetic particles measured by EPI-Lo generally do not preferentially change their directionality from that of the background magnetic field to that of the switchbacks.
Conclusions.
A reasonable hypothesis is that particles with smaller gyroradii, such as strahl electrons, can reverse direction by following the magnetic field in switchbacks, but that larger gyroradii particles cannot. This provides the possibility of setting a constraint on the radius of the curvature of the magnetic field in switchbacks, a property not otherwise observed by PSP. We expect that particles at higher energies than those detectable by EPI-Lo will also not respond to switchbacks. The observed reversals of radial energetic particle flux are separate phenomena, likely associated with source locations or other propagation effects occurring at greater radial distances.
We present a survey for transient and variable sources, on time-scales from 28 s to ∼1 yr, using the Murchison Widefield Array (MWA) at 182 MHz. Down to a detection threshold of 0.285 Jy, no ...transient candidates were identified, making this the most constraining low-frequency survey to date and placing a limit on the surface density of transients of <4.1 × 10−7 deg−2 for the shortest time-scale considered. At these frequencies, emission from Fast Radio Bursts (FRBs) is expected to be detectable in the shortest time-scale images without any corrections for interstellar or intergalactic dispersion. At an FRB limiting flux density of 7980 Jy, we find a rate of <82 FRBs per sky per day for dispersion measures <700 pc cm−3. Assuming a cosmological population of standard candles, our rate limits are consistent with the FRB rates obtained by Thornton et al. if they have a flat spectral slope. Finally, we conduct an initial variability survey of sources in the field with flux densities ≳0.5 Jy and identify no sources with significant variability in their light curves. However, we note that substantial further work is required to fully characterize both the short-term and low-level variability within this field.
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