514 research outputs found

    Invasive Streptococcus pyogenes Infections in <3-Month-Old Infants in France: Clinical and Laboratory Features.

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    Few data are available on invasive group A Streptococcus (GAS) infections (IGASIs) in infants. We described initial clinical and laboratory features and outcomes of <3-month-old infants hospitalized for an IGASI between 2007 and 2016 in France. Patients were identified from the French National Reference Centre for streptococci. IGASI was defined by the isolation of GAS from blood cultures or from other usually sterile sites. Data collection was performed by assessing the patients' hospitalization reports. Twenty-six patients (15 males; 57.7%) were included. Among 19 cases with available data, 14 (73.7%) were household contacts of a GAS infection, reaching 8/9 (88.9%) in neonates. The diagnoses were bacteremia (n = 18; 69.2%), pleural effusion or pneumonia (n = 6; 23.1%), meningitis with brain abscess (n = 1; 3.8%), and septic arthritis (n = 1; 3.8%). Fever (n = 10; 38.5%), hemodynamic disorders (n = 11; 42.3%), respiratory disorders (n = 7; 26.9%), thrombocytopenia (n = 7; 26.9%), and neutropenia (n = 5; 19.2%) were frequently observed. The main emm-genotype was emm-1 (n = 8; 30.8%). Thirteen (50.0%) infants have been admitted to the intensive care unit, and two (7.7%) died. Respiratory disorders, high C-reactive protein level, and the need for transfusion were significantly associated with severity. IGASI remains uncommon in <3-month-old children but leads to a high morbidity. Whether an antibiotic prophylaxis for contact neonates of a patient with GAS infection decreases the risk of infection remains to be determined

    A beginner's introduction to Fukaya categories

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    The goal of these notes is to give a short introduction to Fukaya categories and some of their applications. The first half of the text is devoted to a brief review of Lagrangian Floer (co)homology and product structures. Then we introduce the Fukaya category (informally and without a lot of the necessary technical detail), and briefly discuss algebraic concepts such as exact triangles and generators. Finally, we mention wrapped Fukaya categories and outline a few applications to symplectic topology, mirror symmetry and low-dimensional topology. This text is based on a series of lectures given at a Summer School on Contact and Symplectic Topology at Universit\'e de Nantes in June 2011.Comment: 42 pages, 13 figure

    Effect of Neighborhood Sanitation Coverage on Fecal Contamination of the Household Environment in Rural Bangladesh.

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    Enteric pathogens can be transmitted within the household and the surrounding neighborhood. The objective of this study was to understand the effect of neighborhood-level sanitation coverage on contamination of the household environment with levels of fecal indicator bacteria in rural Bangladesh. We conducted spot-check observations of sanitation facilities in neighboring households (NHs) within a 20-m radius of target households with children aged 6-24 months. Sanitation facilities were defined as improved (a private pit latrine with a slab or better) or unimproved. Fecal coliforms (FCs) on children's hands and sentinel toy balls were measured and used as indicators of household-level fecal contamination. We visited 1,784 NHs surrounding 428 target households. On average, sentinel toy balls had 2.11(standard deviation [SD] = 1.37) log10 colony-forming units (CFUs) of FCs/toy ball and children's hands had 2.23 (SD = 1.15) log10 CFU of FCs/two hands. Access to 100% private improved sanitation coverage in the neighborhood was associated with a small and statistically insignificant difference in contamination of sentinel toy balls (difference in means = -0.13 log10 CFU/toy ball; 95% confidence intervals [CI]: -0.64, 0.39; P = 0.63) and children's hands (difference in means = -0.11 log10 CFU/two hands; 95% CI: -0.53, 0.32; P = 0.62). Improved sanitation coverage in the neighborhood had limited measurable effect on FCs in the target household environment. Other factors such as access to improved sanitation in the household, absence of cow dung, presence of appropriate water drainage, and optimal handwashing practice may be more important in reducing FCs in the household environment

    An exact sequence for contact- and symplectic homology

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    A symplectic manifold WW with contact type boundary M=∂WM = \partial W induces a linearization of the contact homology of MM with corresponding linearized contact homology HC(M)HC(M). We establish a Gysin-type exact sequence in which the symplectic homology SH(W)SH(W) of WW maps to HC(M)HC(M), which in turn maps to HC(M)HC(M), by a map of degree -2, which then maps to SH(W)SH(W). Furthermore, we give a description of the degree -2 map in terms of rational holomorphic curves with constrained asymptotic markers, in the symplectization of MM.Comment: Final version. Changes for v2: Proof of main theorem supplemented with detailed discussion of continuation maps. Description of degree -2 map rewritten with emphasis on asymptotic markers. Sec. 5.2 rewritten with emphasis on 0-dim. moduli spaces. Transversality discussion reorganized for clarity (now Remark 9). Various other minor modification

    On BPS preons, generalized holonomies and D=11 supergravities

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    We develop the BPS preon conjecture to analyze the supersymmetric solutions of D=11 supergravity. By relating the notions of Killing spinors and BPS preons, we develop a moving G-frame method (G=GL(32,R), SL(32,R) or Sp(32,R)) to analyze their associated generalized holonomies. As a first application we derive here the equations determining the generalized holonomies of k/32 supersymmetric solutions and, in particular, those solving the necessary conditions for the existence of BPS preonic (31/32) solutions of the standard D=11 supergravity. We also show that there exist elementary preonic solutions, i.e. solutions preserving 31 out of 32 supersymmetries in a Chern--Simons type supergravity. We present as well a family of worldvolume actions describing the motion of pointlike and extended BPS preons in the background of a D'Auria-Fre type OSp(1|32)-related supergravity model. We discuss the possible implications for M-theory.Comment: 11 pages, RevTeX Typos corrected, a short note and references adde

    A Cross Sectional Study of the Association between Sanitation Type and Fecal Contamination of the Household Environment in Rural Bangladesh.

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    We conducted a cross sectional study to assess 1) the association between access to basic sanitation and fecal contamination of sentinel toy balls and 2) if other sanitation factors such as shared use and cleanliness are associated with fecal contamination of sentinel toy balls. We assessed sanitation facilities in 454 households with a child aged 6-24 months in rural Bangladesh. We defined "basic" sanitation as access to improved sanitation facilities (pit latrine with a slab or better) not shared with other households. In each household, an identical toy ball was given to the target child. After 24 hours, the balls were rinsed to enumerate fecal coliforms as an indicator of household fecal contamination. Households with basic sanitation had lower fecal coliform contamination than households with no access to basic sanitation (adjusted difference in means: -0.31 log10 colony forming units [CFU]/toy ball; 95% confidence interval [CI]: -0.61, -0.01). Shared sanitation facilities of otherwise improved type were more likely to have visible feces on the latrine slab compared with private facilities. Among households with access to improved sanitation, households with no visible feces on the latrine slab had less toy ball contamination than households with visible feces on the latrine slab (adjusted difference in means: -0.38 log10 CFU/toy ball; 95% CI: -0.77, 0.02). Access to basic sanitation may prevent fecal contamination of the household environment. An Improved sanitation facility used by an individual household may be better in preventing household fecal contamination compared with improved facilities shared with other households

    Vacuum interpolation in supergravity via super p-branes

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    We show that many of the recently proposed supersymmetric p-brane solutions of d=10 and d=11 supergravity have the property that they interpolate between Minkowski spacetime and a compactified spacetime, both being supersymmetric supergravity vacua. Our results imply that the effective worldvolume action for small fluctuations of the super p-brane is a supersingleton field theory for (adS)p+2(adS)_{p+2}, as has been often conjectured in the past.Comment: 8p

    The Geometry of D=11 Killing Spinors

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    We propose a way to classify all supersymmetric configurations of D=11 supergravity using the G-structures defined by the Killing spinors. We show that the most general bosonic geometries admitting a Killing spinor have at least a local SU(5) or an (Spin(7)\ltimes R^8)x R structure, depending on whether the Killing vector constructed from the Killing spinor is timelike or null, respectively. In the former case we determine what kind of local SU(5) structure is present and show that almost all of the form of the geometry is determined by the structure. We also deduce what further conditions must be imposed in order that the equations of motion are satisfied. We illustrate the formalism with some known solutions and also present some new solutions including a rotating generalisation of the resolved membrane solutions and generalisations of the recently constructed D=11 Godel solution.Comment: 36 pages. Typos corrected and discussion on G-structures improved. Final version to appear in JHE

    Marginal Deformations of Field Theories with AdS_4 Duals

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    We generate new AdS_4 solutions of D=11 supergravity starting from AdS_4 x X_7 solutions where X_7 has U(1)^3 isometry. We consider examples where X_7 is weak G_2, Sasaki-Einstein or tri-Sasakian, corresponding to d=3 SCFTs with N=1,2 or 3 supersymmetry, respectively, and where the deformed solutions preserve N=1,2 or 1 supersymmetry, respectively. For the special cases when X_7 is M(3,2), Q(1,1,1) or N(1,1)_I we identify the exactly marginal deformation in the dual field theory. We also show that the volume of supersymmetric 5-cycles of N(1,1)_I agrees with the conformal dimension predicted by the baryons of the dual field theory.Comment: 28 pages, 2 figures; v2. typos correcte

    Intersections of quadrics, moment-angle manifolds, and Hamiltonian-minimal Lagrangian embeddings

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    We study the topology of Hamiltonian-minimal Lagrangian submanifolds N in C^m constructed from intersections of real quadrics in a work of the first author. This construction is linked via an embedding criterion to the well-known Delzant construction of Hamiltonian toric manifolds. We establish the following topological properties of N: every N embeds as a submanifold in the corresponding moment-angle manifold Z, and every N is the total space of two different fibrations, one over the torus T^{m-n} with fibre a real moment-angle manifold R, and another over a quotient of R by a finite group with fibre a torus. These properties are used to produce new examples of Hamiltonian-minimal Lagrangian submanifolds with quite complicated topology.Comment: 14 pages, published version (minor changes
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