Asteroid (101955) Bennu, a near‐Earth object with a primitive carbonaceous chondrite‐like composition, was observed by the Origins, Spectral Interpretation, Resource Identification, and ...Security‐Regolith Explorer (OSIRIS‐REx) spacecraft to undergo multiple particle ejection events near perihelion between December 2018 and February 2019. The three largest events observed during this period, which all occurred 3.5 to 6 hr after local noon, placed numerous particles <10 cm on temporary orbits around Bennu. Here we examine whether these events could have been produced by sporadic meteoroid impacts using the National Aeronautics and Space Administration's (NASA) Meteoroid Engineering Model 3.0. Most projectiles that impact Bennu come from nearly isotropic or Jupiter‐family comets and have evolved toward the Sun by Poynting‐Robertson drag. We find that 7,000‐J impacts on Bennu occur with a biweekly cadence near perihelion, with a preference to strike in the late afternoon (~6 pm local time). This timing matches observations. Crater scaling laws also indicate that these impact energies can reproduce the sizes and masses of the largest observed particles, provided the surface has the cohesive properties of weak, porous materials. Bennu's ejection events could be caused by the same kinds of meteoroid impacts that created the Moon's asymmetric debris cloud observed by the Lunar Atmosphere and Dust Environment Explorer (LADEE). Our findings also suggest that fewer ejection events should take place as Bennu moves further away from the Sun, a result that can be tested with future observations.
Plain Language Summary
The asteroid Bennu, the target of the OSIRIS‐REx sample return mission, was observed to be ejecting tiny rocks shortly after the spacecraft entered orbit. The three largest ejection events took place in the late afternoon local time, with an average interval of 2 weeks. Each event launched multicentimeter‐sized and smaller rocks into temporary orbits, where some escaped and others reimpacted Bennu. Given that all inner solar system objects are bombarded by cometary dust particles, we used a NASA model constructed to evaluate spacecraft impact risk to explore whether impacts could be the source of these events. We found that millimeter‐sized cometary dust particles not only strike Bennu in the late afternoon, matching observations, but also produce enough ejected debris to explain the orbiting particles, provided that the material being pummeled is weak.
Key Points
Meteoroids derived from comets strike Bennu near perihelion once every 2 weeks on average with an impact kinetic energy >7,000 J
They can explain the particle sizes (<10 cm), speeds (<3.3 m s−1), and timing (late afternoon) of Bennu's largest observed particle ejection events
For meteoroid impacts to match observations, Bennu's surface must be as porous and structurally weak as common soils
Summary
With the onset of the COVID‐19 pandemic, healthcare providers have made increasing use of inpatient teledermatology; however, few studies have analysed the impact of teledermatology on ...patient outcomes. In this study, we investigated the diagnostic concordance between the primary team and teledermatologist, and we analysed the impact of this technology on the diagnosis and management of erythroderma, a condition with high morbidity and mortality. Overall, out of 2987 inpatient teledermatology encounters reviewed, we found 33 cases of erythroderma, and, of these, 78.8% had a change in diagnosis after teledermatology consult, 81.8% were recommended biopsy and all patients had a change in topical/systemic therapy. We hope to promote further study of the efficacy of teledermatology as it may begin to address large gaps in dermatological access to care particularly in regional and community hospitals.
Dirofilariasis, including heartworm disease, is a major emergent veterinary parasitic infection and a human zoonosis. Currently, experimental infections of cats and dogs are used in veterinary ...heartworm preclinical drug research.
As a refined alternative
heartworm preventative drug screen, we assessed lymphopenic mouse strains with ablation of the interleukin-2/7 common gamma chain (γc) as susceptible to the larval development phase of
.
Non-obese diabetic (NOD) severe combined immunodeficiency (SCID)γc
(NSG and NXG) and recombination-activating gene (RAG)2
γc
mouse strains yielded viable
larvae at 2-4 weeks post-infection, including the use of different batches of
infectious larvae, different
isolates, and at different laboratories. Mice did not display any clinical signs associated with infection for up to 4 weeks. Developing larvae were found in subcutaneous and muscle fascia tissues, which is the natural site of this stage of heartworm in dogs. Compared with
propagated larvae at day 14,
derived larvae had completed the L4 molt, were significantly larger, and contained expanded
endobacteria titres. We established an
L4 paralytic screening system whereby assays with moxidectin or levamisole highlighted discrepancies in relative drug sensitivities in comparison with
reared L4
. We demonstrated effective depletion of
by 70%-90% in
L4 following 2- to 7-day oral
exposures of NSG- or NXG-infected mice with doxycycline or the rapid-acting investigational drug, AWZ1066S. We validated NSG and NXG
mouse models as a filaricide screen by
treatments with single injections of moxidectin, which mediated a 60%-88% reduction in L4 larvae at 14-28 days.
Future adoption of these mouse models will benefit end-user laboratories conducting research and development of novel heartworm preventatives via increased access, rapid turnaround, and reduced costs and may simultaneously decrease the need for experimental cat or dog use.
Grazed pastures based on ryegrass species provide most of the feed for dairy cattle in New Zealand. There are many cultivars of perennial (Lolium perenne), annual and Italian (L. multiflorum), and ...hybrid (L. boucheanum) ryegrasses available for dairy farmers to use in pasture renewal. This study describes an index which ranks ryegrass cultivars relative to a genetic base according to the estimated economic value (EV) of seasonal dry matter (DM) traits. A farm system model was used to derive EVs ($ ha−1 calculated as change in operating profit divided by unit change of the trait) for additional DM produced in different seasons of the year in four regions. The EV of early spring DM was consistently high across all regions, whereas EV for late spring DM was moderate to low. Genotype × environment analysis revealed significant reranking of DM yield among ryegrass cultivars across regions. Hence, separate performance values (PVs) were calculated for two mega‐environments and then combined with the corresponding season and region EV to calculate the overall EV for twenty‐three perennial ryegrass and fifteen short‐term ryegrass cultivars. The difference in operating profit between the highest ranked and lowest ranked perennial ryegrass cultivar ranged from $556 ha−1 to $863 ha−1 year−1 depending on region. For short‐term ryegrasses used for winter feed, the corresponding range was $394 to $478 ha−1 year−1. Using PV for DM yield, it was estimated that plant improvement in perennial ryegrass has added $12–$18 ha−1 year−1 (depending on region) operating profit on dairy farms since the mid‐1960s.
In the mental health sector, Psychological Therapies face numerous challenges including ambiguities over the client and service factors that are linked to unfavourable outcomes. Better understanding ...of these factors can contribute to effective and efficient use of resources within the Service. In this study, process mining was applied to data from the Northern Health and Social Care Trust Psychological Therapies Service (NHSCT PTS). The aim was to explore how psychological distress severity pre-therapy and attendance factors relate to outcomes and how clinicians can use that information to improve the service. Data included therapy episodes (
N
= 2,933) from the NHSCT PTS for adults with a range of mental health difficulties. Data were analysed using Define-Measure-Analyse model with process mining. Results found that around 11% of clients had pre-therapy psychological distress scores below the clinical cut-off and thus these individuals were unlikely to significantly improve. Clients with fewer cancelled or missed appointments were more likely to significantly improve post-therapy. Pre-therapy psychological distress scores could be a useful factor to consider at assessment for estimating therapy duration, as those with higher scores typically require more sessions. This study concludes that process mining is useful in health services such as NHSCT PTS to provide information to inform caseload planning, service management and resource allocation, with the potential to improve client’s health outcomes.
Clinical pathology testing of rodents is often challenging due to insufficient sample volume. One solution in clinical veterinary and exploratory research environments is dilution of samples prior to ...analysis. However, published information on the impact of preanalytical sample dilution on rodent biochemical data is incomplete. The objective of this study was to evaluate the effects of preanalytical sample dilution on biochemical analysis of mouse and rat serum samples utilizing the Siemens Dimension Xpand Plus. Rats were obtained from end of study research projects. Mice were obtained from sentinel testing programs. For both, whole blood was collected
terminal cardiocentesis into empty tubes and serum was harvested. Biochemical parameters were measured on fresh and thawed frozen samples run straight and at dilution factors 2-10. Dilutions were performed manually, utilizing either ultrapure water or enzyme diluent per manufacturer recommendations. All diluted samples were generated directly from the undiluted sample. Preanalytical dilution caused clinically unacceptable bias in most analytes at dilution factors four and above. Dilution-induced bias in total calcium, creatinine, total bilirubin, and uric acid was considered unacceptable with any degree of dilution, based on the more conservative of two definitions of acceptability. Dilution often caused electrolyte values to fall below assay range precluding evaluation of bias. Dilution-induced bias occurred in most biochemical parameters to varying degrees and may render dilution unacceptable in the exploratory research and clinical veterinary environments. Additionally, differences between results obtained at different dilution factors may confound statistical comparisons in research settings. Comparison of data obtained at a single dilution factor is highly recommended.
Chlamydia species are obligate intracellular bacteria that replicate within a membrane-bound vacuole, the inclusion, which is trafficked to the peri-Golgi region by processes that are dependent on ...early chlamydial gene expression. Although neither the host nor the chlamydial proteins that regulate the intracellular trafficking have been clearly defined, several enhanced green fluorescent protein (EGFP)-tagged Rab GTPases, including Rab6, are recruited to Chlamydia trachomatis inclusions. To further characterize the association of Rab6 with C. trachomatis inclusions, we examined the intracellular localization of guanine nucleotide-binding mutants of Rab6 and demonstrated that only active GTP-bound and not inactive GDP-bound EGFP-Rab6 mutants were recruited to the inclusion, suggesting that EGFP-Rab6 interacts with the inclusion via a host Rab6 effector or a chlamydial protein that mimics a Rab6 effector. Using EGFP-tagged fusion proteins, we also demonstrated that the Rab6 effector Bicaudal D1 (BICD1) localized to C. trachomatis inclusions in a biovar-specific manner. In addition, we demonstrated that EGFP-Rab6 and its effector EGFP-BICD1 are recruited to the inclusion in a microtubule- and Golgi apparatus-independent but chlamydial gene expression-dependent mechanism. Finally, in contrast to the Rab6-dependent Golgi apparatus localization of endogenous BICD1, EGFP-BICD1 was recruited to the inclusion by a Rab6-independent mechanism. Collectively, these data demonstrate that neither Rab6 nor BICD1 is trafficked to the inclusion via a Golgi apparatus-localized intermediate, suggesting that each protein is trafficked to the C. trachomatis serovar L2 inclusion by a unique, but as-yet-undefined, mechanism.
Aim
To examine in‐hospital infant feeding practices, focusing on initiation and prevalence of breastmilk expression and to describe the proportion of women having a breast pump immediately after ...birth.
Methods
Postpartum women were recruited from three hospitals in Melbourne, Australia, between 2009 and 2011. Inclusion criteria: having had a healthy singleton term infant, intending to breastfeed and fluency in English. Data were collected using a structured questionnaire.
Results
Just over 1000 women were recruited at 24–48 h postpartum; 50% were primiparous. Forty‐seven per cent of infants had been fully breastfeeding at the breast from birth, and another 47% had received at least some expressed breastmilk. Forty per cent of first‐time mothers reported having had a problem breastfeeding, and 46% already had a breast pump prior to the birth of their infant.
Conclusions
Early breastfeeding problems were common, and less than half the infants had fed only at the breast in the first days of life. Given the normalization of breastmilk expression, more evidence is needed regarding the impact of expressing on duration of breastmilk feeding and maternal health outcomes.
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