8 research outputs found
Light Curves and Colors of the Ejecta from Dimorphos after the DART Impact
On 26 September 2022 the Double Asteroid Redirection Test (DART) spacecraft
impacted Dimorphos, a satellite of the asteroid 65803 Didymos. Because it is a
binary system, it is possible to determine how much the orbit of the satellite
changed, as part of a test of what is necessary to deflect an asteroid that
might threaten Earth with an impact. In nominal cases, pre-impact predictions
of the orbital period reduction ranged from ~8.8 - 17.2 minutes. Here we report
optical observations of Dimorphos before, during and after the impact, from a
network of citizen science telescopes across the world. We find a maximum
brightening of 2.29 0.14 mag upon impact. Didymos fades back to its
pre-impact brightness over the course of 23.7 0.7 days. We estimate lower
limits on the mass contained in the ejecta, which was 0.3 - 0.5% Dimorphos'
mass depending on the dust size. We also observe a reddening of the ejecta upon
impact.Comment: Accepted by Natur
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Cannabinoid type 2 receptors in dopamine neurons inhibits psychomotor behaviors, alters anxiety, depression and alcohol preference
Cannabinoid CB2 receptors (CB2Rs) are expressed in mouse brain dopamine (DA) neurons and are involved in several DA-related disorders. However, the cell type-specific mechanisms are unclear since the CB2R gene knockout mice are constitutive gene knockout. Therefore, we generated Cnr2-floxed mice that were crossed with DAT-Cre mice, in which Cre- recombinase expression is under dopamine transporter gene (DAT) promoter control to ablate Cnr2 gene in midbrain DA neurons of DAT-Cnr2 conditional knockout (cKO) mice. Using a novel sensitive RNAscope in situ hybridization, we detected CB2R mRNA expression in VTA DA neurons in wildtype and DAT-Cnr2 cKO heterozygous but not in the homozygous DAT-Cnr2 cKO mice. Here we report that the deletion of CB2Rs in dopamine neurons enhances motor activities, modulates anxiety and depression-like behaviors and reduces the rewarding properties of alcohol. Our data reveals that CB2Rs are involved in the tetrad assay induced by cannabinoids which had been associated with CB1R agonism. GWAS studies indicates that the CNR2 gene is associated with Parkinson’s disease and substance use disorders. These results suggest that CB2Rs in dopaminergic neurons may play important roles in the modulation of psychomotor behaviors, anxiety, depression, and pain sensation and in the rewarding effects of alcohol and cocaine
Raven Hydrological Modelling Framework
<p>This version has been improved with a handful of modelling features, new algorithms, quality checks on inputs, and minor bug fixes. Notably, the following features have been added:</p>
<p>• New Models Added – full (level 1) emulation support for the HYMOD2 hydrological model (Roy et al., 2017).
• Radiation/ET/Rain-snow partitioning Algorithms – added new algorithms for estimating PET, LW incoming radiation, and partitioning between rain and snow
• Lake Freezing – simple treatment of lake freezing and snow accumulation on frozen lakes with the :LakeFreeze command
• Improved Stream Temperature simulation – better handling of longwave radiation, support for sensible heat exchange and groundwater mixing during in-catchment routing , support for gridded rainfall temperature inputs,
• Basic Model Interface (BMI) interoperability – Raven can now be compiled as a linked library and interface directly with other BMI-compliant applications
• Other – correction factors for wind speed and relative humidity; Spearman ranked correlation coefficient diagnostic, improved support for EnKF in a FEWS environment, improved handling of orographic corrections when using gridded precipitation/temperature data, temperature bias correction, writing of reservoir mass balance file in netCDF format, some previously hard-coded parameters now exposed to users; support for multiple water demands from a single subbasin
• Notable Bug Fixes – repairs to handling of daily-averaged PET estimates, default estimation of longwave radiation, handling lake evaporation when :HRUID not supplied to reservoir, fix to rainfall on reservoirs when :LakeStorage is something other than SURFACE_WATER, repair of reservoir stage assimilation via direct insertion, fixes of netCDF issues when elevation attributes are provided
• Improvements/updates to the Raven documentation and to Raven input quality checking.</p>
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The B73 maize genome: complexity, diversity, and dynamics
We report an improved draft nucleotide sequence of the 2.3-gigabase genome of maize, an important crop plant and model for biological research. Over 32,000 genes were predicted, of which 99.8% were placed on reference chromosomes. Nearly 85% of the genome is composed of hundreds of families of transposable elements, dispersed nonuniformly across the genome. These were responsible for the capture and amplification of numerous gene fragments and affect the composition, sizes, and positions of centromeres. We also report on the correlation of methylation-poor regions with Mu transposon insertions and recombination, and copy number variants with insertions and/or deletions, as well as how uneven gene losses between duplicated regions were involved in returning an ancient allotetraploid to a genetically diploid state. These analyses inform and set the stage for further investigations to improve our understanding of the domestication and agricultural improvements of maize
Reliability of routinely collected anthropometric measurements in primary care
Background
Measuring body mass index (BMI) has been proposed as a method of screening for preventive primary care and population surveillance of childhood obesity. However, the accuracy of routinely collected measurements has been questioned. The purpose of this study was to assess the reliability of height, length and weight measurements collected during well-child visits in primary care relative to trained research personnel.
Methods
A cross-sectional study of measurement reliability was conducted in community pediatric and family medicine primary care practices. Each participating child, ages 0 to 18 years, was measured four consecutive times; twice by a primary care team member (e.g. nurses, practice personnel) and twice by a trained research assistant. Inter- and intra-observer reliability was calculated using the technical error of measurement (TEM), relative TEM (%TEM), and a coefficient of reliability (R).
Results
Six trained research assistants and 16 primary care team members performed measurements in three practices. All %TEM values for intra-observer reliability of length, height, and weight were classified as ‘acceptable’ ( 99% for both intra- and inter-observer reliability. Length measurements in children
Conclusion
There was agreement between routine measurements and research measurements although there were some differences in length measurement reliability between practice staff and research assistants. These results provide justification for using routinely collected data from selected primary care practices for secondary purposes such as BMI population surveillance and research.</p
Maternal ethnicity and iron status in early childhood in Toronto, Canada: a cross-sectional study
Objectives This study aimed to evaluate the association between maternal ethnicity and iron deficiency (ID) in early childhood, and to evaluate whether infant feeding practices linked to ID differ between maternal ethnic groups.Methods This was a cross-sectional study of healthy children 1–3 years of age. Adjusted multivariable logistic regression analyses were used to evaluate the association between maternal ethnicity and ID (serum ferritin <12 µg/L) and the association between maternal ethnicity and five infant feeding practices (breastfeeding duration; bottle use beyond 15 months; current formula use; daily cow’s milk intake >2 cups; meat consumption).Results Of 1851 children included, 12.2% had ID. Compared with the European referent group, we found higher odds of ID among children of South Asian and West Asian/North African maternal ethnicities, and lower odds of ID among children of East Asian maternal ethnicity. Statistically significant covariates associated with higher odds of ID included longer breastfeeding duration and daily cow’s milk intake >2 cups. Current infant formula use was associated with lower odds of ID. Children of South Asian maternal ethnicity had higher odds of bottle use beyond 15 months of age and lower odds of meat consumption.Conclusions We found increased odds of ID among children of South Asian and West Asian/Northern African maternal ethnicities. We found a higher odds of feeding practices linked to ID in children of South Asian maternal ethnicity, but not in children of West Asian/North African maternal ethnicity. Culturally tailored approaches to providing guidance to parents on healthy infant feeding practices may be important to prevent ID in early childhood.Trial registration number NCT01869530