21 research outputs found
WISE/NEOWISE Preliminary Analysis and Highlights of the 67P/Churyumov-Gerasimenko Near Nucleus Environs
On January 18-19 and June 28-29 of 2010, the Wide-field Infrared Survey
Explorer (WISE) spacecraft imaged the Rosetta mission target, comet
67P/Churyumov-Gerasimenko. We present a preliminary analysis of the images,
which provide a characterization of the dust environment at heliocentric
distances similar to those planned for the initial spacecraft encounter, but on
the outbound leg of its orbit rather than the inbound. Broad-band photometry
yields low levels of CO2 production at a comet heliocentric distance of 3.32 AU
and no detectable production at 4.18 AU. We find that at these heliocentric
distances, large dust grains with mean grain diameters on the order of a
millimeter or greater dominate the coma and evolve to populate the tail. This
is further supported by broad-band photometry centered on the nucleus, which
yield an estimated differential dust particle size distribution with a power
law relation that is considerably shallower than average. We set a 3-sigma
upper limit constraint on the albedo of the large-grain dust at <= 0.12. Our
best estimate of the nucleus radius (1.82 +/- 0.20 km) and albedo (0.04 +/-
0.01) are in agreement with measurements previously reported in the literature
WISE/NEOWISE observations of Active Bodies in the Main Belt
We report results based on mid-infrared photometry of 5 active main belt
objects (AMBOs) detected by the Wide-field Infrared Survey Explorer (WISE)
spacecraft. Four of these bodies, P/2010 R2 (La Sagra), 133P/Elst-Pizarro,
(596) Scheila, and 176P/LINEAR, showed no signs of activity at the time of the
observations, allowing the WISE detections to place firm constraints on their
diameters and albedos. Geometric albedos were in the range of a few percent,
and on the order of other measured comet nuclei. P/2010 A2 was observed on
April 2-3, 2010, three months after its peak activity. Photometry of the coma
at 12 and 22 {\mu}m combined with ground-based visible-wavelength measurements
provides constraints on the dust particle mass distribution (PMD), dlogn/dlogm,
yielding power-law slope values of {\alpha} = -0.5 +/- 0.1. This PMD is
considerably more shallow than that found for other comets, in particular
inbound particle fluence during the Stardust encounter of comet 81P/Wild 2. It
is similar to the PMD seen for 9P/Tempel 1 in the immediate aftermath of the
Deep Impact experiment. Upper limits for CO2 & CO production are also provided
for each AMBO and compared with revised production numbers for WISE
observations of 103P/Hartley 2.Comment: 32 Pages, including 5 Figure
Centaurs and Scattered Disk Objects in the Thermal Infrared: Analysis of WISE/NEOWISE Observations
The Wide-field Infrared Survey Explorer (WISE) observed 52 Centaurs and scattered disk objects (SDOs) in the thermal infrared, including 15 new discoveries. We present analyses of these observations to estimate sizes and mean optical albedos. We find mean albedos of 0.08 ± 0.04 for the entire data set. Thermal fits yield average beaming parameters of 0.9 ± 0.2 that are similar for both SDO and Centaur sub-classes. Biased cumulative size distributions yield size-frequency distribution power law indices of ~â1.7 ± 0.3. The data also reveal a relation between albedo and color at the 3Ï level. No significant relation between diameter and albedos is found
PANC Study (Pancreatitis: A National Cohort Study): national cohort study examining the first 30 days from presentation of acute pancreatitis in the UK
Abstract
Background
Acute pancreatitis is a common, yet complex, emergency surgical presentation. Multiple guidelines exist and management can vary significantly. The aim of this first UK, multicentre, prospective cohort study was to assess the variation in management of acute pancreatitis to guide resource planning and optimize treatment.
Methods
All patients aged greater than or equal to 18 years presenting with acute pancreatitis, as per the Atlanta criteria, from March to April 2021 were eligible for inclusion and followed up for 30 days. Anonymized data were uploaded to a secure electronic database in line with local governance approvals.
Results
A total of 113 hospitals contributed data on 2580 patients, with an equal sex distribution and a mean age of 57 years. The aetiology was gallstones in 50.6 per cent, with idiopathic the next most common (22.4 per cent). In addition to the 7.6 per cent with a diagnosis of chronic pancreatitis, 20.1 per cent of patients had a previous episode of acute pancreatitis. One in 20 patients were classed as having severe pancreatitis, as per the Atlanta criteria. The overall mortality rate was 2.3 per cent at 30 days, but rose to one in three in the severe group. Predictors of death included male sex, increased age, and frailty; previous acute pancreatitis and gallstones as aetiologies were protective. Smoking status and body mass index did not affect death.
Conclusion
Most patients presenting with acute pancreatitis have a mild, self-limiting disease. Rates of patients with idiopathic pancreatitis are high. Recurrent attacks of pancreatitis are common, but are likely to have reduced risk of death on subsequent admissions.
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Mouse Models of Uncomplicated and Fatal Malaria.
Mouse models have demonstrated utility in delineating the mechanisms underlying many aspects of malaria immunology and physiology. The most common mouse models of malaria employ the rodent-specific parasite species Plasmodium berghei, P. yoelii, and P. chabaudi, which elicit distinct pathologies and immune responses and are used to model different manifestations of human disease. In vitro culture methods are not well developed for rodent Plasmodium parasites, which thus require in vivo maintenance. Moreover, physiologically relevant immunological processes are best studied in vivo. Here, we detail the processes of infecting mice with Plasmodium, maintaining the parasite in vivo, and monitoring parasite levels and health parameters throughout infection
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Mouse Models of Uncomplicated and Fatal Malaria.
Mouse models have demonstrated utility in delineating the mechanisms underlying many aspects of malaria immunology and physiology. The most common mouse models of malaria employ the rodent-specific parasite species Plasmodium berghei, P. yoelii, and P. chabaudi, which elicit distinct pathologies and immune responses and are used to model different manifestations of human disease. In vitro culture methods are not well developed for rodent Plasmodium parasites, which thus require in vivo maintenance. Moreover, physiologically relevant immunological processes are best studied in vivo. Here, we detail the processes of infecting mice with Plasmodium, maintaining the parasite in vivo, and monitoring parasite levels and health parameters throughout infection
COVIDâ19 vaccine hesitancy: The synergistic effect of anxiety and proactive coping
Abstract Background This study sought to identify cognitive and behavioral predictors of COVIDâ19 vaccine hesitancy. Specifically, this study examined the effect of anxiety about developing COVIDâ19 and proactive coping behavior on the likelihood of reporting COVIDâ19 vaccine hesitancy in a sample of adults living in the United States. Methods An online survey of proactive coping strategies, anxiety related to developing COVIDâ19, and vaccine hesitancy was administered in October 2020 to 534 adults aged 21â79âyears old. Age, gender, race, selfârated health, years of education, COVIDâ19 knowledge, and perceived constraints were included as covariates. Results Over half of the study participants (56.7%) were COVIDâ19 vaccine hesitant. People who were less anxious about developing COVIDâ19 were more likely to be vaccine hesitant. A statistically significant COVIDâ19 anxiety Ă proactive coping interaction showed the odds of vaccine hesitancy was highest among individuals with low anxiety about developing COVIDâ19 and high proactive coping, whereas vaccine hesitancy was lowest among individuals with high COVIDâ19 anxiety and high proactive coping. Conclusion Results support a futureâoriented approach to public health outreach efforts regarding COVIDâ19 vaccines. Improvement of proactive coping skills and emphasis on the likelihood of contracting COVIDâ19 may be more effective in increasing vaccine uptake than simply restating scientific facts regarding safety or efficacy
The influence of morphological variation on migration performance in a trans-hemispheric migratory songbird
For long-distance migratory songbirds,
morphological traits such as longer wings and a smaller
body size are predicted to increase migration efficiency.
Due to previous limitations in our ability to track the
long-distance journeys of small-bodied birds, the
relationship between morphology and start-to-finish
migration performance has never been fully tested in
free-living songbirds. Using direct-tracking data obtained
from light-level geolocators, we examined the effects of
morphological factors (wing and body size) on spring
and fall migration performance (flight speed, duration of
stopovers, total stopovers taken) of a widely distributed,
trans-hemispheric migratory songbird, the purple martin
(Progne subis) (n = 120). We found that smaller-bodied
birds spent fewer days at stopovers along fall migration,
but larger-bodied birds spent fewer days at stopover and
took fewer stopovers during spring migration. More of the
variation in fall migration performance was explained
by morphology, as compared to spring migration, possibly indicating a larger influence of environmental
conditions on spring performance. Overall, our results
partially support long-standing and previously untested
predictions regarding the influence of intrinsic factors on
migration performance. Future research should examine
the influence of environmental variation on migration
performance as well as additional morphological traits
that may contribute to migration performance
"Our desire is to make this village intestinal worm free": Identifying determinants of high coverage of community-wide mass drug administration for soil transmitted helminths in Benin, India, and Malawi.
BackgroundSoil-transmitted helminth infections (STH) are associated with substantial morbidity in low-and-middle-income countries, accounting for 2.7 million disability-adjusted life years annually. Current World Health Organization guidelines recommend controlling STH-associated morbidity through periodic deworming of at-risk populations, including children and women of reproductive age (15-49 years). However, there is increasing interest in community-wide mass drug administration (cMDA) which includes deworming adults who serve as infection reservoirs as a method to improve coverage and possibly to interrupt STH transmission. We investigated determinants of cMDA coverage by comparing high-coverage clusters (HCCs) and low-coverage clusters (LCCs) receiving STH cMDA in three countries.MethodsA convergent mixed-methods design was used to analyze data from HCCs and LCCs in DeWorm3 trial sites in Benin, India, and Malawi following three rounds of cMDA. Qualitative data were collected via 48 community-level focus group discussions. Quantitative data were collected via routine activities nested within the DeWorm3 trial, including annual censuses and coverage surveys. The Consolidated Framework for Implementation Research (CFIR) guided coding, theme development and a rating process to determine the influence of each CFIR construct on cMDA coverage.ResultsOf 23 CFIR constructs evaluated, we identified 11 constructs that differentiated between HCCs and LCCs, indicating they are potential drivers of coverage. Determinants differentiating HCC and LCC include participant experiences with previous community-wide programs, communities' perceptions of directly observed therapy (DOT), perceptions about the treatment uptake behaviors of neighbors, and women's agency to make household-level treatment decisions.ConclusionThe convergent mixed-methods study identified barriers and facilitators that may be useful to NTD programs to improve cMDA implementation for STH, increase treatment coverage, and contribute to the successful control or elimination of STH.Trial registrationThe parent trial was registered at clinicaltrials.gov (NCT03014167)