Aims.
Our aim was to directly detect the thermal emission of the putative exoring system responsible for the complex deep transits observed in the light curve for the young Sco-Cen star 1SWASP ...J140747.93-394542.6 (V1400 Cen, hereafter J1407), confirming it as the occulter seen in May 2007, and to determine its orbital parameters with respect to the star.
Methods.
We used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the field centred on J1407 in the 340 GHz (Band 7) continuum in order to determine the flux and astrometric location of the ring system relative to the star. We used the VLT/NACO camera to observe the J1407 system in March 2019 and to search for the central planetary mass object at thermal infrared wavelengths.
Results.
We detect no point source at the expected location of J1407, and derive an upper limit 3
σ
level of 57.6
μ
Jy. There is a point source detected at an angular separation consistent with the expected location for a free-floating ring system that occulted J1407 in May 2007, with a flux of 89
μ
Jy consistent with optically thin dust surrounding a massive substellar companion. At 3.8
μ
m with the NACO camera, we detect the star J1407 but no other additional point sources within 1.3 arcsec of the star, with a lower bound on the sensitivity of 6
M
Jup
at the location of the ALMA source, and down to 4
M
Jup
in the sky background limit.
Conclusions.
The ALMA upper limit at the location of J1407 implies that a hypothesised bound ring system is composed of dust smaller than 1 mm in size, implying a young ring structure. The detected ALMA source has multiple interpretations, including: (i) it is an unbound substellar object surrounded by warm dust in Sco-Cen with an upper mass limit of 6
M
Jup
, or (ii) it is a background galaxy.
As part of annual cross-sectional Streptococcus pneumoniae carriage surveys in Fiji (2012–2015), we detected pneumococci in over 100 nasopharyngeal swabs that serotyped as ‘11F-like’ by microarray. ...We examined the genetic basis of this divergence in the 11F-like capsular polysaccharide (cps) locus compared to the reference 11F cps sequence. The impact of this diversity on capsule phenotype, and serotype results using genetic and serologic methods were determined.
Genomic DNA from representative 11F-like S. pneumoniae isolates obtained from the nasopharynx of Fijian children was extracted and subject to whole genome sequencing. Genetic and phylogenetic analyses were used to identify genetic changes in the cps locus. Capsular phenotypes were evaluated using the Quellung reaction and latex agglutination.
Compared to published 11F sequences, the wcwC and wcrL genes of the 11F-like cps locus are phylogenetically divergent, and the gct gene contains a single nucleotide insertion within a homopolymeric region. These changes within the DNA sequence of the 11F-like cps locus have modified the antigenic properties of the capsule, such that 11F-like isolates serotype as 11A by Quellung reaction and latex agglutination.
This study demonstrates the ability of molecular serotyping by microarray to identify genetic variants of S. pneumoniae and highlights the potential for discrepant results between phenotypic and genotypic serotyping methods. We propose that 11F-like isolates are not a new serotype but rather are a novel genetic variant of serotype 11A. These findings have implications for invasive pneumococcal disease surveillance as well as studies investigating vaccine impact.
Like many Sub-Saharan countries, Angola struggles with a shortage of trained health professionals, especially for primary care. In 2021, the Angolan Ministry of Health in collaboration with the ...Angolan Medical Council launched the National Program for the Expansion of Family Medicine as a long-term strategy for the provision, fixation and training of family physicians in community health centres. Of the 425 residents 411 (96.7%) who entered the programme in 2021 will get their diplomas in the following months and will be certified as family physicians. Three main aspects make this National Programme unique in the Angolan context: (1) the common effort and engagement of the Ministry of Health with the Angolan Medical Council and local health authorities in designing and implementing this programme; (2) decentralisation of the training sites, with residents in all 18 provinces, including in rural areas and (3) using community health centres as the main site of practice and training. Despite this undeniable success, many educational improvements must be made, such as expanding the use of new educational resources, methodologies and assessment tools, so that aspects related to knowledge, practical skills and professional attitudes can be better assessed. Moreover, the programme must invest in faculty development courses aiming to create the next generation of preceptors, so that all residents can have in every rotation one preceptor or tutor responsible for the supervision of their clinical activities, case discussions and sharing their clinical duties, both at community health centres and municipal hospitals.
Optical images of the nearby star Fomalhaut show a ring of dust orbiting the central star. This dust is in many respects expected to be similar to the zodiacal dust in the solar system. The ring ...displays a clear brightness asymmetry, attributed to asymmetric scattering of the central starlight by the circumstellar dust grains. Recent measurements show that the bright side of the Fomalhaut ring is oriented away from us. This implies that the grains in this system scatter most of the light in the backward direction, in sharp contrast to the forward-scattering nature of the grains in the solar system. In this letter, we show that grains considerably larger than those dominating the solar system zodiacal dust cloud provide a natural explanation for the apparent backward scattering behavior. In fact, we see the phases of the dust grains in the same way as we can observe the phases of the Moon and other large solar system bodies. We outline how the theory of the scattering behavior of planetesimals can be used to explain the Fomalhaut dust properties. This indicates that the Fomalhaut dust ring is dominated by very large grains. The material orbiting Fomalhaut, which is at the transition between dust and planetesimals, can, with respect to their optical behavior, best be described as micro-asteroids.
The freeze-out of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as ...carbon monoxide (CO), the freeze-out of various carriers of elements with abundances < 10-5 has not yet been well studied. We observed transitions of HCl and Hsub 2Clsup + towards OMC-2 FIR 4 using the Herschel Space Observatory and Caltech Sub-millimeter Observatory facilities. Our analysis makes use of state of the art chlorine gas-grain chemical models and newly calculated Hcl-Hsub 2 hyperfine collisional excitation rate coefficients. Gas-phase HCl is the tip of the chlorine iceberg in protostellar cores. Using a gas-grain chemical model, we show that the hydrogenation of atomic chlorine on grain surfaces in the dark cloud stage sequesters at least 90% of the volatile chlorine into HCl ice, where it remains in the protostellar stage. About 10% of chlorine is in gaseous atomic form.
Context. Despite intensive studies of protoplanetary disks, there is still no reliable way to determine their total (gast+dust) mass and their surface density distribution, quantities that are ...crucial for describing both the structure and the evolution of disks up to the formation of planets. Aims. The goal of this work is to use less-abundant CO isotopologues, such as 13CO, C18O and C17O, detection of which is routine for ALMA, to infer the gas mass of disks. Isotope-selective effects need to be taken into account in the analysis, because they can significantly modify CO isotopologues’ line intensities. Methods. CO isotope-selective photodissociation has been implemented in the physical-chemical code DALI (Dust And LInes) and more than 800 disk models have been run for a range of disk and stellar parameters. Dust and gas temperature structures have been computed self-consistently, together with a chemical calculation of the main atomic and molecular species. Both disk structure and stellar parameters have been investigated by varying the parameters in the grid of models. Total fluxes have been ray-traced for different CO isotopologues and for various low J-transitions for different inclinations. Results. A combination of 13CO and C18O total intensities allows inference of the total disk mass, although with non-negligible uncertainties. These can be overcome by employing spatially resolved observations, that is the disk’s radial extent and inclination. Comparison with parametric models shows differences at the level of a factor of a few, especially for extremely low and high disk masses. Finally, total line intensities for different CO isotopologue and for various low-J transitions are provided and are fitted to simple formulae. The effects of a lower gas-phase carbon abundance and different gas-to-dust ratios are investigated as well, and comparison with other tracers is made. Conclusions. Disk masses can be determined within a factor of a few by comparing CO isotopologue lines observations with the simulated line fluxes provided in this paper, modulo the uncertainties in the volatile elemental abundances.
Context. Broadband spectral surveys of protostars offer a rich view of the physical, chemical and dynamical structure and evolution of star-forming regions. The Herschel Space Observatory opened up ...the terahertz regime to such surveys, giving access to the fundamental transitions of many hydrides and to the high-energy transitions of many other species. Aims. A comparative analysis of the chemical inventories and physical processes and properties of protostars of various masses and evolutionary states is the goal of the Herschel CHEmical Surveys of Star forming regions (CHESS) key program. This paper focusses on the intermediate-mass protostar, OMC-2 FIR 4. Methods. We obtained a spectrum of OMC-2 FIR 4 in the 480 to 1902 GHz range with the HIFI spectrometer onboard Herschel and carried out the reduction, line identification, and a broad analysis of the line profile components, excitation, and cooling. Results. We detect 719 spectral lines from 40 species and isotopologs. The line flux is dominated by CO, H sub(2)O, and CH sub(3)OH. The line profiles are complex and vary with species and upper level energy, but clearly contain signatures from quiescent gas, a broad component likely due to an outflow, and a foreground cloud. Conclusions. We find abundant evidence for warm, dense gas, as well as for an outflow in the field of view. Line flux represents 2% of the 7 Lmiddot in circle luminosity detected with HIFI in the 480 to 1250 GHz range. Of the total line flux, 60% is from CO, 13% from H sub(2)O and 9% from CH sub(3)OH. A comparison with similar HIFI spectra of other sources is set to provide much new insight into star formation regions, a case in point being a difference of two orders of magnitude in the relative contribution of sulphur oxides to the line cooling of Orion KL and OMC-2 FIR 4.
In 2012, Fiji introduced the 10-valent pneumococcal conjugate vaccine (PCV10). We assessed the impact of PCV10 on invasive pneumococcal disease (IPD), probable bacterial or pneumococcal meningitis ...(PBPM), meningitis and sepsis 3-5 years post-introduction.
Laboratory-confirmed IPD and PBPM cases were extracted from national laboratory records. ICD-10-AM coded all-cause meningitis and sepsis cases were extracted from national hospitalisation records. Incidence rate ratios were used to compare outcomes pre/post-PCV10, stratified by age groups: 1-23m, 2-4y, 5-9y, 10-19y, 20-54y, ≥55y. To account for different detection and serotyping methods in the pre-and post-PCV10 period, a Bayesian inference model estimated serotype-specific changes in IPD, using pneumococcal carriage and surveillance data.
There were 423 IPD, 1,029 PBPM, 1,391 all-cause meningitis and 7,611 all-cause sepsis cases. Five years post-PCV10 introduction, IPD declined by 60% (95%CI: 37%, 76%) in children 1-23m months old, and in age groups 2-4y, 5-9y, 10-19y although confidence intervals spanned zero. PBPM declined by 36% (95%CI: 21%, 48%) among children 1-23 months old, and in all other age groups, although some confidence intervals spanned zero. Among children <5y of age, PCV10-type IPD declined by 83% (95%CI; 70%, 90%) and with no evidence of change in non-PCV10-type IPD (9%, 95%CI; -69, 43%). There was no change in all-cause meningitis or sepsis. Post-PCV10, the most common serotypes in vaccine age-eligible and non-age eligible people were serotypes 8 and 23B, and 3 and 7F, respectively.
Our study demonstrates the effectiveness of PCV10 against IPD in a country in the Asia-Pacific of which there is a paucity of data.
This study was support by the Department of Foreign Affairs and Trade of the Australian Government and Fiji Health Sector Support Program (FHSSP). FHSSP is implemented by Abt JTA on behalf of the Australian Government.
Context. The Orion A molecular complex is a nearby (420 pc), very well studied stellar nursery that is believed to contain examples of triggered star formation. Aims. As part of the Herschel ...guaranteed time key programme CHESS, we present the discovery of a diffuse gas component in the foreground of the intermediate-mass protostar OMC-2 FIR 4, located in the Orion A region. Methods. Making use of the full HIFI spectrum of OMC-2 FIR 4 obtained in CHESS, we detected several ground-state lines from OH+, H2O+, HF, and CH+, all of them seen in absorption against the dust continuum emission of the protostar’s envelope. We derived column densities for each species, as well as an upper limit to the column density of the undetected H3O+. In order to model and characterise the foreground cloud, we used the Meudon PDR code to run a homogeneous grid of models that spans a reasonable range of densities, visual extinctions, cosmic ray ionisation rates and far-ultraviolet (FUV) radiation fields, and studied the implications of adopting the Orion Nebula extinction properties instead of the standard interstellar medium ones. Results. The detected absorption lines peak at a velocity of 9 km s-1, which is blue-shifted by 2 km s-1 with respect to the systemic velocity of OMC-2 FIR 4 (VLSR = 11.4 km s-1). The results of our modelling indicate that the foreground cloud is composed of predominantly neutral diffuse gas (nH = 100 cm-3) and is heavily irradiated by an external source of FUV that most likely arises from the nearby Trapezium OB association. The cloud is 6 pc thick and bears many similarities with the so-called C+ interface between Orion-KL and the Trapezium cluster, 2 pc south of OMC-2 FIR 4. Conclusions. We conclude that the foreground cloud we detected is an extension of the C+ interface seen in the direction of Orion KL, and interpret it to be the remains of the parental cloud of OMC-1, which extends from OMC-1 up to OMC-2.
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