During the roll out of vaccines during a pandemic, questions regarding vaccine safety often arise. This was surely true during the SARS-CoV-2 pandemic. Different tools and capabilities exist during ...the pre-authorization phase and post introduction each with its strengths and limitations. Here we review the various tools and their strengths and limitations and discuss what functioned well in high income settings and the limitations that unequal vaccine safety pharmacovigilance capacity imposed upon middle and low income countries.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The Green Revolution dwarfing genes, Rht-B1b and Rht-D1b, encode mutant forms of DELLA proteins and are present in most modern wheat varieties. DELLA proteins have been implicated in the response to ...biotic stress in the model plant, Arabidopsis thaliana. Using defined wheat Rht near-isogenic lines and barley Sln1 gain of function (GoF) and loss of function (LoF) lines, the role of DELLA in response to biotic stress was investigated in pathosystems representing contrasting trophic styles (biotrophic, hemibiotrophic, and necrotrophic). GoF mutant alleles in wheat and barley confer a resistance trade-off with increased susceptibility to biotrophic pathogens and increased resistance to necrotrophic pathogens whilst the converse was conferred by a LoF mutant allele. The polyploid nature of the wheat genome buffered the effect of single Rht GoF mutations relative to barley (diploid), particularly in respect of increased susceptibility to biotrophic pathogens. A role for DELLA in controlling cell death responses is proposed. Similar to Arabidopsis, a resistance trade-off to pathogens with contrasting pathogenic lifestyles has been identified in monocotyledonous cereal species. Appreciation of the pleiotropic role of DELLA in biotic stress responses in cereals has implications for plant breeding.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
ABSTRACT
More than 50 per cent of solar-mass stars form in multiple systems. It is therefore crucial to investigate how multiplicity affects the star and planet formation processes at the ...protostellar stage. We report continuum and C18O (2–1) observations of the VLA 1623–2417 protostellar system at 50 au angular resolution as part of the ALMA (Atacama Large Millimeter/submillimeter Array) Large Program FAUST. The 1.3 mm continuum probes the discs of VLA 1623A, B, and W, and the circumbinary disc of the A1 + A2 binary. The C18O emission reveals, for the first time, the gas in the disc envelope of VLA 1623W. We estimate the dynamical mass of VLA 1623W, Mdyn = 0.45 ± 0.08 M⊙, and the mass of its disc, Mdisc ∼ 6 × 10−3 M⊙. C18O also reveals streamers that extend up to 1000 au, spatially and kinematically connecting the envelope and outflow cavities of the A1 + A2 + B system with the disc of VLA 1623W. The presence of the streamers, as well as the spatial (∼1300 au) and velocity (∼2.2 km s−1) offsets of VLA 1623W, suggests that either sources W and A + B formed in different cores, interacting between them, or source W has been ejected from the VLA 1623 multiple system during its formation. In the latter case, the streamers may funnel material from the envelope and cavities of VLA 1623AB on to VLA 1623W, thus concurring to set its final mass and chemical content.
ABSTRACT
The ALMA interferometer has played a key role in revealing a new component of the Sun-like star forming process: the molecular streamers, i.e. structures up to thousands of au long ...funnelling material non-axisymmetrically to discs. In the context of the FAUST ALMA LP, the archetypical VLA1623-2417 protostellar cluster has been imaged at 1.3 mm in the SO(56–45), SO(66–55), and SiO(5–4) line emission at the spatial resolution of 50 au. We detect extended SO emission, peaking towards the A and B protostars. Emission blue-shifted down to 6.6 km s−1 reveals for the first time a long (∼ 2000 au) accelerating streamer plausibly feeding the VLA1623 B protostar. Using SO, we derive for the first time an estimate of the excitation temperature of an accreting streamer: 33 ± 9 K. The SO column density is ∼ 1014 cm−2, and the SO/H2 abundance ratio is ∼ 10−8. The total mass of the streamer is 3 × 10−3M⊙, while its accretion rate is 3–5 × 10−7M⊙ yr−1. This is close to the mass accretion rate of VLA1623 B, in the 0.6–3 × 10−7M⊙ yr−1 range, showing the importance of the streamer in contributing to the mass of protostellar discs. The highest blue- and red-shifted SO velocities behave as the SiO(5–4) emission, the latter species detected for the first time in VLA1623-2417: the emission is compact (100–200 au), and associated only with the B protostar. The SO excitation temperature is ∼ 100 K, supporting the occurrence of shocks associated with the jet, traced by SiO.
Binary and multiple star systems are a frequent outcome of the star formation process and as a result almost half of all stars with masses similar to that of the Sun have at least one companion star. ...Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large-scale fragmentation of turbulent gas cores and filaments or smaller-scale fragmentation of a massive protostellar disk due to gravitational instability. Observational evidence for turbulent fragmentation on scales of more than 1,000 astronomical units has recently emerged. Previous evidence for disk fragmentation was limited to inferences based on the separations of more-evolved pre-main sequence and protostellar multiple systems. The triple protostar system L1448 IRS3B is an ideal system with which to search for evidence of disk fragmentation as it is in an early phase of the star formation process, it is likely to be less than 150,000 years old and all of the protostars in the system are separated by less than 200 astronomical units. Here we report observations of dust and molecular gas emission that reveal a disk with a spiral structure surrounding the three protostars. Two protostars near the centre of the disk are separated by 61 astronomical units and a tertiary protostar is coincident with a spiral arm in the outer disk at a separation of 183 astronomical units. The inferred mass of the central pair of protostellar objects is approximately one solar mass, while the disk surrounding the three protostars has a total mass of around 0.30 solar masses. The tertiary protostar itself has a minimum mass of about 0.085 solar masses. We demonstrate that the disk around L1448 IRS3B appears susceptible to disk fragmentation at radii between 150 and 320 astronomical units, overlapping with the location of the tertiary protostar. This is consistent with models for a protostellar disk that has recently undergone gravitational instability, spawning one or two companion stars.
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IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
FAUST Vastel, C.; Alves, F.; Ceccarelli, C. ...
Astronomy and astrophysics (Berlin),
08/2022, Volume:
664, Issue:
1
Journal Article
Peer reviewed
Open access
Aims.
Methanol is a ubiquitous species commonly found in the molecular interstellar medium. It is also a crucial seed species for the build-up of chemical complexity in star forming regions. Thus, ...understanding how its abundance evolves during the star formation process and whether it enriches the emerging planetary system is of paramount importance.
Methods.
We used new data from the ALMA Large Program FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar protostars) to study the methanol line emission towards the BHB2007 11 protobinary system (sources A and B), where a complex structure of filaments connecting the two sources with a larger circumbinary disc has previously been detected.
Results.
Twelve methanol lines have been detected with upper energies in the 45–537 K range along with one
13
CH
3
OH transition and one methyl formate (CH
3
OCHO) line blended with one of the methanol transitions. The methanol emission is compact (FWHM ~ 0.5″) and encompasses both protostars, which are separated by only 0.2″ (28 au). In addition, the overall methanol line emission presents three velocity components, which are not spatially resolved by our observations. Nonetheless, a detailed analysis of the spatial origin of these three components suggests that they are associated with three different spatial regions, with two of them close to 11B and the third one associated with 11A. A radiative transfer analysis of the methanol lines gives a kinetic temperature of 100–140 K, an H
2
volume density of 10
6
–10
7
cm
−3
and column density of a few 10
18
cm
−2
in all three components with a source size of ~0.15″. Thus, this hot and dense gas is highly enriched in methanol with an abundance as high as 10
−5
. Using previous continuum data, we show that dust opacity can potentially completely absorb the methanol line emission from the two binary objects.
Conclusions.
Although we cannot firmly exclude other possibilities, we suggest that the detected hot methanol is resulting from the shocked gas from the incoming filaments streaming towards BHB2007 11A and B, respectively. Higher spatial resolution observations are necessary to confirm this hypothesis.
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FMFMET, NUK, UL, UM, UPUK
We present high spatial resolution observations of the multiple protostellar system IRAS 16293-2422 using the Submillimeter Array (SMA) at 300 GHz and the Very Large Array (VLA) at frequencies from ...1.5 to 43 GHz. This source was already known to be a binary system with its main components, A and B, separated by 65". The new SMA data now separate source A into two submillimeter continuum components, which we denote Aa and Ab. The strongest of these, Aa, peaks between the centimeter radio sources A1 and A2, but the resolution of the current submillimeter data is insufficient to distinguish whether this is a separate source or the centroid of submillimeter dust emission associated with A1 and A2. Archival VLA data spanning 18 yr show proper motion of sources A and B of 17 mas yr super(-1), associated with the motion of the r Ophiuchi cloud. We also find, however, significant relative motion between the centimeter sources A1 and A2, which excludes the possibility that these two sources are gravitationally bound unless A1 is in a highly eccentric orbit and is observed at periastron, the probability of which is low. A2 remains stationary relative to source B, and we identify it as the protostar that drives the large-scale northeast-southwest CO outflow. A1 is shock-ionized gas that traces the location of the interaction between a precessing jet and nearby dense gas. This jet probably drives the large-scale east-west outflow, and indeed its motion is consistent with the wide opening angle of this flow. The origin of this jet must be located close to A2 and may be the submillimeter continuum source Aa. Thus, source A is now shown to comprise three (proto)stellar components within 1". Source B, on the other hand, is single, exhibits optically thick dust emission even at 8 GHz, has a high luminosity, and yet shows no sign of outflow. It is probably very young and may not even have begun a phase of mass loss yet. The SMA spectrum of IRAS 16293-2422 reports the first astronomical identification of many lines of organic and other molecules at 300 and 310 GHz. The species detected are typical of hot cores, the emission from which is mainly associated with source A. The abundances of second-generation species, especially of sulphur-bearing molecules, are significantly higher than predicted by chemical models for this source to date, and we suggest that shocks are probably needed to explain these enhancements. The peaks in the integrated emission from molecules having high rotation temperatures coincide with the centimeter source A1, also highlighting the key role of shocks in explaining the nature of hot cores. Finally, we use the high brightness temperature of the submillimeter dust emission from source B to demonstrate the unambiguous detection of infall by observing redshifted SO (7 sub(7)-6 sub(6)) absorption against the emission from its dust disk.
Gastroschisis is a significant birth defect that in many countries has shown an increased prevalence in recent decades, and the change has affected primarily younger mothers. Despite numerous ...epidemiological studies no other consistent associated risk factor has been identified. In this paper we review the five main theories related to the pathogenesis of this malformation and outline the reasons why we think none fully explains the embryogenesis of gastroschisis. We briefly present some clinical observations we have made that we consider germane to the pathogenesis and outline a hypothesis that we think can account for the origins of this malformation. Our proposal is that the determining defect in gastroschisis is failure of the yolk sac and related vitelline structures to be incorporated into the umbilical stalk. Otherwise, ventral closure of the lateral abdominal walls occurs normally, thus orphaning the vitelline duct and yolk sac outside both the main body stalk and the abdominal wall. Thus, in addition to the umbilicus, the abdominal wall has a separate perforation through which the midpoint of the gut is attached to the exteriorized vitelline structures. This connection through the ventral wall prevents normal egress of the gut into the umbilical cord during the second month of development and acts as the egress point for the gut resulting in gastroschisis.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The transforming growth factor beta (TGFβ) superfamily member Nodal is an established regulator of early embryonic development, with primary roles in endoderm induction, left-right asymmetry, and ...primitive streak formation. Nodal signals through TGFβ family receptors at the plasma membrane and induces signaling cascades leading to diverse transcriptional regulation. While conceptually simple, the regulation of Nodal and its molecular effects are profoundly complex and context dependent. Pioneering work by developmental biologists has characterized the signaling pathways, regulatory components, and provided detailed insight into the mechanisms by which Nodal mediates changes at the cellular and organismal levels. Nodal is also an important factor in maintaining pluripotency of embryonic stem cells through regulation of core transcriptional programs. Collectively, this work has led to an appreciation for Nodal as a powerful morphogen capable of orchestrating multiple cellular phenotypes. Although Nodal is not active in most adult tissues, its reexpression and signaling have been linked to multiple types of human cancer, and Nodal has emerged as a driver of tumor growth and cellular plasticity.
In vitro
and
in vivo
experimental evidence has demonstrated that inhibition of Nodal signaling reduces cancer cell aggressive characteristics, while clinical data have established associations with Nodal expression and patient outcomes. As a result, there is great interest in the potential targeting of Nodal activity in a therapeutic setting for cancer patients that may provide new avenues for suppressing tumor growth and metastasis. In this review, we evaluate our current understanding of the complexities of Nodal function in cancer and highlight recent experimental evidence that sheds light on the therapeutic potential of its inhibition.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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