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Determining infectious cross-transmission events in healthcare settings involves manual surveillance of case clusters by infection control personnel, followed by strain typing of clinical/environmental isolates suspected in said clusters. Recent advances in genomic sequencing and cloud computing now allow for the rapid molecular typing of infecting isolates.
To facilitate rapid recognition of transmission clusters, we aimed to assess infection control surveillance using whole-genome sequencing (WGS) of microbial pathogens to identify cross-transmission events for epidemiologic review.
Clinical isolates of Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, and Klebsiella pneumoniae were obtained prospectively at an academic medical center, from September 1, 2016, to September 30, 2017. Isolate genomes were sequenced, followed by single-nucleotide variant analysis; a cloud-computing platform was used for whole-genome sequence analysis and cluster identification.
Most strains of the 4 studied pathogens were unrelated, and 34 potential transmission clusters were present. The characteristics of the potential clusters were complex and likely not identifiable by traditional surveillance alone. Notably, only 1 cluster had been suspected by routine manual surveillance.
Our work supports the assertion that integration of genomic and clinical epidemiologic data can augment infection control surveillance for both the identification of cross-transmission events and the inclusion of missed and exclusion of misidentified outbreaks (ie, false alarms). The integration of clinical data is essential to prioritize suspect clusters for investigation, and for existing infections, a timely review of both the clinical and WGS results can hold promise to reduce HAIs. A richer understanding of cross-transmission events within healthcare settings will require the expansion of current surveillance approaches.
, and let
be a Lagrangian embedding of
into the cotangent bundle
that agrees with the cotangent fiber
over a point
outside a compact set. Assume that
is disjoint from the cotangent fiber at the origin. The projection of
to the base extends to a map of the
. We show that this map is homotopically trivial, answering a question of Eliashberg. We give a number of generalizations of this result, including homotopical constraints on embedded Lagrangian disks in the complement of another Lagrangian submanifold, and on two-component links of immersed Lagrangian spheres with one double point in
, under suitable dimension and Maslov index hypotheses. The proofs combine techniques from Ekholm and Smith [Exact Lagrangian immersions with a single double point, J. Amer. Math. Soc. 29 (2016), 1–59] and Ekholm and Smith [Exact Lagrangian immersions with one double point revisited, Math. Ann. 358 (2014), 195–240] with symplectic field theory.
Twelve accelerator mass spectrometry (AMS) radiocarbon dates from the shell-matrix site of Canímar Abajo (Matanzas, Cuba) are reported. Eleven were obtained directly from human bone collagen in burials and one was obtained from charcoal recovered from a burial context. The site stratigraphy presents two episodes of burial activity separated by a shell midden layer. The AMS dates fall into two compact clusters that correlate remarkably well with the stratigraphy. The older burial dates to between 1380–800 cal BC (2σ) and the younger one to between cal AD 360–950 (2σ). The AMS dates are compared to eight conventional 14C dates previously obtained on shell and charcoal. One of the conventional dates on charcoal (5480–5380 cal BC; 2σ) has been reported as the oldest 14C date in the Caribbean region; its context and reliability are clarified. The suite of AMS dates provides one of the most reliable chronometric dating of a cultural context during this timeframe in Cuba. The correlation of 14C and stratigraphy establishes a solid chronology for investigating the important economic and ritual features of Canímar Abajo.
We present an analysis of the parsec-scale jet structure of the quasar 4C+21.35 with a resolution of 0.1 milliarcseconds based on 63 epochs of Very Long Baseline Array observations at 43 GHz from 2007 June to 2014 May along with the Fermi LAT γ-ray light curve and multi-frequency optical photometric and polarimetric data. We find that the innermost jet of the quasar consists of a very compact core of size ~0.03 mas, as well as feature A1 located 0.16 ± 0.03 mas from the core. The distance of A1 remains fairly stable, but its position angle with respect to the core changes from -10 to +10 deg. We detect 4 superluminal knots in the inner jet with apparent speeds ranging from 10c to 20c. The first two components appeared in the jet during the high γ-ray state of the quasar from mid-2010 to early 2011, while the fourth knot appears to be connected with the γ-ray active state in late 2013 - early 2014. The first knot can be associated with the dramatic VHE flare in 2010 June and possesses an extreme Doppler factor ~60. We find that maxima in the γ-ray light curve coincide with epochs of interaction between the moving knots and the core and feature A1. This suggests that the core and A1 are recollimation shocks where γ-ray flares occur. The Chandra 0.5-6 keV image reveals the existence of X-ray emission in the kiloparsec scale jet of the quasar that can be explained via inverse Compton scattering off the cosmic microwave background by relativistic electrons if no deceleration occurs between the parsec- and kiloparsec-scale jets.
Ideas from conformal field theory are applied to symplectic four-manifolds through the use of modular functors to ‘linearise’ Lefschetz fibrations. In Chern–Simons theory, this leads to the study of parabolic vector bundles of conformal blocks. Motivated by the Hard Lefschetz theorem, the author shows that the bundles of SU(2) conformal blocks associated to Kähler surfaces are Brill–Noether special, although the associated flat connexions may be irreducible if the surface is simply connected and not spin.
We have investigated the properties of main-sequence O-type stars in the SMC. Mass-loss rates, luminosities and Teff are much smaller for these stars than for Galactic ones, resulting in a steeper wind-momentum relation.
This study examined how one aspect of intensive cultivation, double digging by hand (loosening the planting bed to 50 cm deep), contributed to crop productivity and nutrient uptake in bush beans (1994 and 1995) and red beets (1995 only). Comparison beds were prepared with the soil cultivated to 25 cm (single dig) and 6 cm (surface cultivation). Although there were significant differences (1994 beans) between the surface cultivated beds and other cultivation types for leaf mass and chlorophyll content, there were no significant differences in the total mass of beans (whole fruit) produced. There were no significant differences in beet green or root (edible portion) biomass among cultivation methods. Levels of Ca, Mg, and K in the bean fruits and beet roots were not significantly different among cultivation methods. This study demonstrated that deep cultivation significantly alters the soil profile as measured by penetrometer resistance, but that this change does not necessarily alter productivity or nutrient uptake. We suggest that deep hand tillage has little effect on crop productivity in well-watered and moderate to high fertility soils. These results are similar to those found in mechanically subsoiled systems.
Although NLTE model atmospheres have been shown to resolve most of the equivalent width (EW) discrepancies for blue He I lines (Auer and Mihalas 1972, 1973), Wolff and Heasley (1984, 1985) have demonstrated that discrepancies remain for the leading members of the singlet/triplet 2P – nD series, viz. λ6678 and λ5876. These two lines are the strongest nonresonance He I transitions and are important because they respond to thermal changes in the superficial atmosphere (τ~ 10-3) of early B stars. In order to understand the observed rapid variations of the λ6678 line in mild Be stars, we undertook a survey of EWs of λ6678 and λ4388, namely the first and third member of the same series. These two lines have a log gf ratio of 15 but have similar EWs in B star spectra. Our new observations confirm the red line discrepancy noted by WH85 and point to additional EW differences among various groups of B stars not noted hitherto.