328 research outputs found
Transcriptome analysis and systemic RNAi response in the African sweetpotato weevil (Cylas puncticollis, Coleoptera, Brentidae
<div><p>The African sweetpotato weevil (SPW) <i>Cylas puncticollis</i> Boheman is one of the most important constraints of sweetpotato production in Sub-Saharan Africa and yet is largely an uncharacterized insect pest. Here, we report on the transcriptome analysis of SPW generated using an Illumina platform. More than 213 million sequencing reads were obtained and assembled into 89,599 contigs. This assembly was followed by a gene ontology annotation. Subsequently, a transcriptome search showed that the necessary RNAi components relevant to the three major RNAi pathways, were found to be expressed in SPW. To address the functionality of the RNAi mechanism in this species, dsRNA was injected into second instar larvae targeting <i>laccase2</i>, a gene which encodes an enzyme involved in the sclerotization of insect exoskeleton. The body of treated insects showed inhibition of sclerotization, leading eventually to death. Quantitative Real Time PCR (qPCR) confirmed this phenotype to be the result of gene silencing. Together, our results provide valuable sequence data on this important insect pest and demonstrate that a functional RNAi pathway with a strong and systemic effect is present in SPW and can further be explored as a new strategy for controlling this important pest.</p></div
Induction of Labor for Maternal Indications at a Periviable Gestational Age; Survey on Management, Reporting and Auditing amongst Dutch Maternal-Feta Medicine Specialists and Neonatologists
Background In cases of life-threatening maternal conditions in the periviable period, professionals may consider immediate delivery with fetal demise as a consequence of the treatment. We sought the opinion of involved medical professionals on management, reporting, and auditing in these cases.Methods We performed an online survey amongst all registered maternal-fetal medicine (MFM) specialists and neonatologists in the Netherlands. The survey presented two hypothetical cases of severe early-onset pre-eclampsia at periviable gestational ages. Management consisted of immediate termination or expectant management directed towards newborn survival.Findings In the case managed by immediate termination, 62% percent answered that fetal demise resulting from induction of labor for maternal indications should be audited only within the medical profession. In the case of expectant management, 17% of the participants agreed with this management. Some answers revealed a significant difference in opinion between the medical specialists.Conclusion Perspective of MFM specialists and neonatologists differs with regard to counseling prospect parents in case of severe early onset pre-eclampsia. The majority of professionals is willing to report late termination (after 24 weeks' gestation) for severe maternal disease to medical experts for internal audits but not for legal auditing.</p
MATERNAL UNIPARENTAL DISOMY FOR CHROMOSOME 22 IN A CHILD WITH GENERALIZED MOSAICISM FOR TRISOMY 22
A faint companion around CrA-9: protoplanet or obscured binary?
Understanding how giant planets form requires observational input from
directly imaged protoplanets. We used VLT/NACO and VLT/SPHERE to search for
companions in the transition disc of 2MASS J19005804-3645048 (hereafter CrA-9),
an accreting M0.75 dwarf with an estimated age of 1-2 Myr. We found a faint
point source at 0.7'' separation from CrA-9 (108 au projected
separation). Our 3-epoch astrometry rejects a fixed background star with a
significance. The near-IR absolute magnitudes of the object point
towards a planetary-mass companion. However, our analysis of the 1.0-3.8m
spectrum extracted for the companion suggests it is a young M5.5 dwarf, based
on both the 1.13-m Na index and comparison with templates of the Montreal
Spectral Library. The observed spectrum is best reproduced with high effective
temperature (K) BT-DUSTY and BT-SETTL models, but the
corresponding photometric radius required to match the measured flux is only
Jovian radius. We discuss possible explanations to
reconcile our measurements, including an M-dwarf companion obscured by an
edge-on circum-secondary disc or the shock-heated part of the photosphere of an
accreting protoplanet. Follow-up observations covering a larger wavelength
range and/or at finer spectral resolution are required to discriminate these
two scenarios.Comment: 24 pages, 14 figures, 4 tables, to be published in MNRA
First CLAS12 Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries in the Extended Valence Region
Deeply virtual Compton scattering (DVCS) allows one to probe generalized parton distributions describing the 3D structure of the nucleon. We report the first measurement of the DVCS beam-spin asymmetry using the CLAS12 spectrometer with a 10.2 and 10.6 GeV electron beam scattering from unpolarized protons. The results greatly extend the Q2 and Bjorken-x phase space beyond the existing data in the valence region and provide 1600 new data points measured with unprecedented statistical uncertainty, setting new, tight constraints for future phenomenological studies
Discovery of a low-mass companion inside the debris ring surrounding the F5V star HD 206893
Aims: Uncovering the ingredients and the architecture of planetary systems is a very active field of research that has fuelled many new theories on giant planet formation, migration, composition, and interaction with the circumstellar environment. We aim at discovering and studying new such systems, to further expand our knowledge of how low-mass companions form and evolve. Methods: We obtained high-contrast H-band images of the circumstellar environment of the F5V star HD 206893, known to host a debris disc never detected in scattered light. These observations are part of the SPHERE High Angular Resolution Debris Disc Survey (SHARDDS) using the InfraRed Dual-band Imager and Spectrograph (IRDIS) installed on VLT/SPHERE. Results: We report the detection of a source with a contrast of 3.6 × 10[SUP]-5[/SUP] in the H-band, orbiting at a projected separation of 270 milliarcsec or 10 au, corresponding to a mass in the range 24 to 73 M[SUB]Jup[/SUB] for an age of the system in the range 0.2 to 2 Gyr. The detection was confirmed ten months later with VLT/NaCo, ruling out a background object with no proper motion. A faint extended emission compatible with the disc scattered light signal is also observed. Conclusions: The detection of a low-mass companion inside a massive debris disc makes this system an analog of other young planetary systems such as β Pictoris, HR 8799 or HD 95086 and requires now further characterisation of both components to understand their interactions.Peer reviewe
Circumstellar discs: What will be next?
This prospective chapter gives our view on the evolution of the study of
circumstellar discs within the next 20 years from both observational and
theoretical sides. We first present the expected improvements in our knowledge
of protoplanetary discs as for their masses, sizes, chemistry, the presence of
planets as well as the evolutionary processes shaping these discs. We then
explore the older debris disc stage and explain what will be learnt concerning
their birth, the intrinsic links between these discs and planets, the hot dust
and the gas detected around main sequence stars as well as discs around white
dwarfs.Comment: invited review; comments welcome (32 pages
Water in the terrestrial planet-forming zone of the PDS 70 disk
Terrestrial and sub-Neptune planets are expected to form in the inner
(AU) regions of protoplanetary disks. Water plays a key role in their
formation, although it is yet unclear whether water molecules are formed
in-situ or transported from the outer disk. So far Spitzer Space Telescope
observations have only provided water luminosity upper limits for dust-depleted
inner disks, similar to PDS 70, the first system with direct confirmation of
protoplanet presence. Here we report JWST observations of PDS 70, a benchmark
target to search for water in a disk hosting a large (AU)
planet-carved gap separating an inner and outer disk. Our findings show water
in the inner disk of PDS 70. This implies that potential terrestrial planets
forming therein have access to a water reservoir. The column densities of water
vapour suggest in-situ formation via a reaction sequence involving O, H,
and/or OH, and survival through water self-shielding. This is also supported by
the presence of CO emission, another molecule sensitive to UV
photodissociation. Dust shielding, and replenishment of both gas and small dust
from the outer disk, may also play a role in sustaining the water reservoir.
Our observations also reveal a strong variability of the mid-infrared spectral
energy distribution, pointing to a change of inner disk geometry.Comment: To appear in Nature on 24 July 2023. 21 pages, 10 figures; includes
extended data. Part of the JWST MINDS Guaranteed Time Observations program's
science enabling products. Spectra downloadable on Zenodo at
https://zenodo.org/record/799102
Effects of gestational age at birth on perinatal structural brain development in healthy term-born babies
Infants born in early term (37-38 weeks gestation) experience slower neurodevelopment than those born at full term (40-41 weeks gestation). While this could be due to higher perinatal morbidity, gestational age at birth may also have a direct effect on the brain. Here we characterise brain volume and white matter correlates of gestational age at birth in healthy term-born neonates and their relationship to later neurodevelopmental outcome using T2 and diffusion weighted MRI acquired in the neonatal period from a cohort (n = 454) of healthy babies born at term age (>37 weeks gestation) and scanned between 1 and 41 days after birth. Images were analysed using tensor-based morphometry and tract-based spatial statistics. Neurodevelopment was assessed at age 18 months using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). Infants born earlier had higher relative ventricular volume and lower relative brain volume in the deep grey matter, cerebellum and brainstem. Earlier birth was also associated with lower fractional anisotropy, higher mean, axial, and radial diffusivity in major white matter tracts. Gestational age at birth was positively associated with all Bayley-III subscales at age 18 months. Regression models predicting outcome from gestational age at birth were significantly improved after adding neuroimaging features associated with gestational age at birth. This work adds to the body of evidence of the impact of early term birth and highlights the importance of considering the effect of gestational age at birth in future neuroimaging studies including term-born babies
Development of microstructural and morphological cortical profiles in the neonatal brain
Interruptions to neurodevelopment during the perinatal period may have long-lasting consequences. However, to be able to investigate deviations in the foundation of proper connectivity and functional circuits, we need a measure of how this architecture evolves in the typically developing brain. To this end, in a cohort of 241 term-born infants, we used magnetic resonance imaging to estimate cortical profiles based on morphometry and microstructure over the perinatal period (37-44 weeks postmenstrual age, PMA). Using the covariance of these profiles as a measure of inter-areal network similarity (morphometric similarity networks; MSN), we clustered these networks into distinct modules. The resulting modules were consistent and symmetric, and corresponded to known functional distinctions, including sensory-motor, limbic, and association regions, and were spatially mapped onto known cytoarchitectonic tissue classes. Posterior regions became more morphometrically similar with increasing age, while peri-cingulate and medial temporal regions became more dissimilar. Network strength was associated with age: Within-network similarity increased over age suggesting emerging network distinction. These changes in cortical network architecture over an 8-week period are consistent with, and likely underpin, the highly dynamic processes occurring during this critical period. The resulting cortical profiles might provide normative reference to investigate atypical early brain development
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