Respiratory syncytial virus (RSV) is the leading cause of hopitalisation in young children with respiratory tract infections (RTI). The aim of this research project was to analyse RSV genotypes and ...the diversification of RSV strains among hospitalised children in Heidelberg, Germany.
We prospectively analysed nasopharyngeal swabs (NPS) from children who were hospitalised with acute RTI at the University Hospital Heidelberg, Germany, during winter seasons 2014 to 2017. RSV RT-PCR and RSV sequence analysis of the G gene coding for the attachment glycoprotein were performed. Clinical data was obtained using a standardised questionnaire.
RSV was detected in 405 out of 946 samples from hospitalised children. Most RSV positive children were below the age of two years (84.4%) and had a lower RTI (78.8%). The majority of RSV positive children was male, significantly younger than RSV negative children with a median age of 0.39 years and with more severe respiratory symptoms. Out of 405 positive samples, 317 RSV strains were successfully sub-grouped into RSV subtypes A (57.4%; 182/317) and B (42.6%; 135/317). Both RSV subtypes cocirculated in all analysed winter seasons. Phylogenetic analysis of 317 isolates revealed that the majority of RSV-A strains (180/182) belonged to the ON1 genotype, most RSV-B strains could be attributed to the BAIX genotype (132/135). ON1 and BAIX strains showed a sub-differentiation into different lineages and we were able to identify new (sub)genotypes.
Analysis of the molecular epidemiology of RSV from different seasons revealed the cocirculation and diversification of RSV genotypes ON1 and BAIX.
•RSV is an important cause for hospitalization of children in Heidelberg/Germany.•RSV subtypes A and B cocirculated in all winter seasons 2014–2017.•The majority of RSV-A strains belonged to the ON1 genotype.•Most RSV-B strains could be attributed to the BAIX genotype.•Genotypes ON1 and BAIX cocirculation and diversified across all seasons.
Compact substructure is expected to arise in a starless core as mass becomes concentrated in the central region likely to form a protostar. Additionally, multiple peaks may form if fragmentation ...occurs. We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 2 observations of 60 starless and protostellar cores in the Ophiuchus molecular cloud. We detect eight compact substructures which are from the nearest Spitzer young stellar object. Only one of these has strong evidence for being truly starless after considering ancillary data, e.g., from Herschel and X-ray telescopes. An additional extended emission structure has tentative evidence for starlessness. The number of our detections is consistent with estimates from a combination of synthetic observations of numerical simulations and analytical arguments. This result suggests that a similar ALMA study in the Chamaeleon I cloud, which detected no compact substructure in starless cores, may be due to the peculiar evolutionary state of cores in that cloud.
We present new measurements of the dust emissivity index, β, for the high-mass, star-forming OMC 2/3 filament. We combined 160−500 μm data from Herschel with long-wavelength observations at 2 mm and ...fit the spectral energy distributions across a ≃2 pc long, continuous section of OMC 2/3 at 15 000 AU (0.08 pc) resolution. With these data, we measured β and reconstructed simultaneously the filtered-out large-scale emission at 2 mm. We implemented both variable and fixed values of β, finding that β = 1.7−1.8 provides the best fit across most of OMC 2/3. These β values are consistent with a similar analysis carried out with filtered Herschel data. Thus, we show that β values derived from spatial filtered emission maps agree well with those values from unfiltered data at the same resolution. Our results contradict the very low β values (~0.9) previously measured in OMC 2/3 between 1.2 mm and 3.3 mm data, which we attribute to elevated fluxes in the 3.3 mm observations. Therefore, we find no evidence of rapid, extensive dust grain growth in OMC 2/3. Future studies with Herschel data and complementary ground-based long-wavelength data can apply our technique to obtain reliable determinations of β in nearby cold molecular clouds.
We have detected bright HC7N J = 21 − 20 emission towards multiple locations in the Serpens South cluster-forming region using the K-Band Focal Plane Array at the Robert C. Byrd Green Bank Telescope. ...HC7N is seen primarily towards cold filamentary structures that have yet to form stars, largely avoiding the dense gas associated with small protostellar groups and the main central cluster of Serpens South. Where detected, the HC7N abundances are similar to those found in other nearby star-forming regions. Towards some HC7N 'clumps', we find consistent variations in the line centroids relative to NH3 (1,1) emission, as well as systematic increases in the HC7N non-thermal line widths, which we argue reveal infall motions on to dense filaments within Serpens South with minimum mass accretion rates of M ∼ 2-5 M Myr−1. The relative abundance of NH3 to HC7N suggests that the HC7N is tracing gas that has been at densities n ∼ 104 cm−3 for time-scales t 1-2 × 105 yr. Since HC7N emission peaks are rarely co-located with those of either NH3 or continuum, it is likely that Serpens South is not particularly remarkable in its abundance of HC7N, but instead the serendipitous mapping of HC7N simultaneously with NH3 has allowed us to detect HC7N at low abundances in regions where it otherwise may not have been looked for. This result extends the known star-forming regions containing significant HC7N emission from typically quiescent regions, like the Taurus molecular cloud, to more complex, active environments.
Stilbene phytoalexins are identified as defence response in pathogen–grapevine interactions, but little information is available on the role of stilbenes on
Erysiphe necator, causal agent of ...grapevine powdery mildew. Analysis of stilbenes in artificially infected leaf discs from susceptible to highly resistant cultivars was performed and compared to the development of the pathogen. Results indicate that stilbene synthesis is confined in infected cells, penetrated by an appressorium–peg. Stilbene amounts expressed by infection site allow discriminating susceptible and resistant cultivars. Highest viniferins concentrations on resistant cultivars are in correspondence with the observed inhibition of the pathogen growth. The analysis of stilbenes at the infection site and viniferins accumulation in grapevine defence reaction is discussed.
Core accretion models of massive star formation require the existence of stable massive starless cores, but robust observational examples of such objects have proven elusive. We report ...subarcsecond-resolution Submillimeter Array (SMA) 1.3 mm, 1.1 mm, and 0.88 mm and Very Large Array 1.3 cm observations of an excellent massive starless core candidate, G11.92-0.61-MM2, initially identified in the course of studies of GLIMPSE Extended Green Objects (EGOs). Separated by ~7".2 from the nearby MM1 protostellar hot core, MM2 is a strong, compact dust continuum source (submillimeter spectral index alpha = 2.6 + or - 0.1), but is devoid of star formation indicators. In contrast to MM1, MM2 has no masers, no centimeter continuum, and no (sub)millimeter wavelength line emission in ~24 GHz of bandwidth observed with the SMA, including N sub(2)H super(+)(3-2), HCO super(+)(3-2), and HCN(3-2). Additionally, there is no evidence for an outflow driven by MM2. The (sub)millimeter spectral energy distribution of MM2 is best fit with a dust temperature of ~17-19K and luminosity of ~5-7 L sub(middot in circle). The combined physical properties of MM2, as inferred from its dust continuum emission, are extreme; M > ~ 30 M sub(middot in circle) within a radius < 1000 AU, N sub(H2) > 10 super(25) cm super(-2) and n sub(H), > 10 super(9) cm super(-3). Comparison of the molecular abundance limits derived from our SMA observations with gas-grain chemical models indicates that extremely dense (n(H) >> 10 super(8) cm super(-3)), cold (<20 K) conditions are required to explain the lack of observed (sub)millimeter line emission, consistent with the dust continuum results. Our data suggest that G11.92-0.61-MM2 is the best candidate for a bonafide massive prestellar core found to date, and a promising target for future higher-sensitivity observations.
Background and Aims
Plasmopara viticola development in bunches of two grapevine cultivars, the resistant Divico and the susceptible Chasselas, was studied by using microscopy and molecular detection ...to investigate tissue susceptibility and the extent of colonisation.
Methods and Results
Bunches were inoculated with P. viticola at four phenological stages, and the development of downy mildew was recorded. Visible symptoms were evident after the first three inoculation stages for Chasselas. Inoculation at inflorescence swelling resulted in the desiccation of the inflorescence and at the end of flowering led to desiccation of parts of the bunches with some berries developing normally until ripening. After inoculation of pea‐sized berries, brown rot symptoms appeared, whereas no infections were observed after inoculation at veraison. Histological and molecular examination showed that downy mildew invaded almost all bunch tissues but required an active stomata as an infection site. Mycelium and haustoria, however, were never observed in the vascular tissues. For Divico, inoculation at early stages of development resulted in sparse infections with limited colonisation.
Conclusion
Downy mildew systemic development occurs only between adjacent tissues meaning that as the stomata lose function the severity of the infection is reduced.
Significance of the Study
Limited infection justifies the maintenance of a fungicide control program for the resistant cultivar Divico.
Using far-infrared emission maps taken by IRAS and Spitzer and a near-infrared extinction map derived from 2MASS data, we have made dust temperature and column density maps of the Perseus molecular ...cloud. We show that the emission from transiently heated very small grains (VSGs) and the big grain dust emissivity vary as a function of extinction and dust temperature, with higher dust emissivities for colder grains. This variable emissivity cannot be explained by temperature gradients along the line of sight or by noise in the emission maps, but it is consistent with grain growth in the higher density and lower temperature regions. By accounting for the variations in the dust emissivity and VSG emission, we are able to map the temperature and column density of a nearby molecular cloud with better accuracy than has previously been possible.
We present single-dish observations of the L1689-SMM16 core in the Ophiuchus molecular cloud in NH sub(3) (1,1) and (2, 2) emission using the Green Bank Telescope, in N sub(2)H super(+) (1-0) ...emission using the Nobeyama Radio Observatory, and in NH sub(2)D (1a sub(1,1)-1s sub(0,1)), HCN (1-0), HNC (1-0), H super(l3)CO super(+) (1-0), and HCO+ (1-0) emission using the Mopra telescope. The morphologies of the integrated NH sub(3) (1, 1) and N sub(2)H super(+) (1-0) emission well match that of 250 mu m continuum emission. Line widths of NH sub(3) (1, 1) and N sub(2)H super(+) (1-0) show the presence of transonic turbulence across the core. Jeans and virial analyses made using updated measurements of core mass and size confirm that L1689-SMM16 is prestellar, i.e., gravitationally bound. It also has accumulated more mass compared to its corresponding Jeans mass in the absence of magnetic fields and therefore is a "super-Jeans" core. The high levels of X(NH sub(3))/X(N sub(2)H super(+)) and deuterium fractionation reinforce the idea that the core has not yet formed a protostar. Comparing the physical parameters of the core with those of a Bonnor-Ebert sphere reveals the advanced evolutionary stage of L1689-SMM16 and shows that it might be unstable to collapse. We do not detect any evidence of infall motions toward the core. Instead, red asymmetry in the line profiles of HCN (1-0) and HNC (1-0) indicates the expansion of the outer layers of the core at a speed of ~0.2 km s super(-1) to 0.3 km s super(-1). For a gravitationally bound core, expansion in the outer layers might indicate that the core is experiencing oscillations.
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